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Utility of CT oral contrast administration in the emergency department of a quaternary oncology hospital: diagnostic implications, turnaround times, and assessment of ED physician ordering

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Purpose: To compare studies with and without oral contrast on performance of multidetector computed tomography (CT) and the order to CT examination turnaround time in cancer patients presenting to the emergency department (ED). To the best of our knowledge, oral contrast utility has not previously been specifically assessed in cancer patients presenting to the emergency department. Materials & methods: Retrospective review of CT abdomen examinations performed in oncology patients presenting to the emergency department during one month. CT examinations performed with and without oral contrast were rated by two consensus readers for degree of confidence and diagnostic ability. Correlations were assessed for primary cancer type, age, sex, chief complaint/examination indication, body mass index, intravenous contrast status, repeat CT examination within 4 weeks, and disposition. Turnaround times from order to the start of the CT examination were calculated. Results: The studied group consisted of 267 patients (127 men and 140 women) with a mean age of 56 years and a mean body mass index of 27.8 kg/m(2). One hundred sixty CT examinations were performed without oral contrast, and 107 CT examinations were performed with oral contrast. There was no significant difference between cases with oral contrast and cases without oral contrast in the number of cases rated as "improved confidence" (odds ratio [OR] 0.54, 95% confidence interval [CI] 0.23-1.31, P = 0.17), "improved diagnosis" (OR 0.58, 95% CI 0.20-1.64, P = 0.3), "impaired confidence" (OR 3.92, 95% CI 0.46-33.06, P = 0.21), or "impaired diagnosis" (OR 2.63, 95% CI 0.29-23.89, P = 0.39). The turnaround time in the group receiving oral contrast (mean, 141 min; standard deviation, 49.8 min) was significantly longer than that in the group not receiving oral contrast (mean, 109.2 min; standard deviation, 64.8 min) with a mean difference of 31.8 min (P < 0.0001). Conclusion: On the basis of our findings and prior studies, targeted rather than default use of oral contrast shows acceptable diagnostic ability in the emergency setting for oncology patients. Benefit from oral contrast use is suggested in scenarios such as suspected fistula/bowel leak/abscess, hypoattenuating peritoneal disease, prior bowel surgery such as gastric bypass, and the absence of intravenous contrast administration. Improvement through the use of targeted oral contrast administration also supports the emergency department need for prompt diagnosis and disposition.
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Utility of CT oral contrast administration
in the emergency department of a quaternary
oncology hospital: diagnostic implications,
turnaround times, and assessment of ED
physician ordering
Corey T. Jensen,
1
Katherine J. Blair,
1
Ott Le,
1
Jia Sun,
2
Wei Wei,
2
Brinda Rao Korivi,
1
Ajaykumar C. Morani,
1
Nicolaus A. Wagner-Bartak
1
1
Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, 1400 Pressler Street, Unit 1473,
Houston, TX 77030-4009, USA
2
Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
Abstract
Purpose: To compare studies with and without oral
contrast on performance of multidetector computed
tomography (CT) and the order to CT examination
turnaround time in cancer patients presenting to the
emergency department (ED). To the best of our knowl-
edge, oral contrast utility has not previously been
specifically assessed in cancer patients presenting to the
emergency department.
Materials & methods: Retrospective review of CT abdo-
men examinations performed in oncology patients pre-
senting to the emergency department during one month.
CT examinations performed with and without oral
contrast were rated by two consensus readers for degree
of confidence and diagnostic ability. Correlations were
assessed for primary cancer type, age, sex, chief com-
plaint/examination indication, body mass index, intra-
venous contrast status, repeat CT examination within
4 weeks, and disposition. Turnaround times from order
to the start of the CT examination were calculated.
Results: The studied group consisted of 267 patients (127
men and 140 women) with a mean age of 56 years and a
mean body mass index of 27.8 kg/m
2
. One hundred sixty
CT examinations were performed without oral contrast,
and 107 CT examinations were performed with oral
contrast. There was no significant difference between
cases with oral contrast and cases without oral contrast
in the number of cases rated as ‘‘improved confidence’’
(odds ratio [OR] 0.54, 95%confidence interval [CI]
0.23–1.31, P= 0.17), ‘‘improved diagnosis’’ (OR 0.58,
95%CI 0.20–1.64, P= 0.3), ‘‘impaired confidence’’ (OR
3.92, 95%CI 0.46–33.06, P= 0.21), or ‘‘impaired
diagnosis’’ (OR 2.63, 95%CI 0.29–23.89, P= 0.39).
The turnaround time in the group receiving oral contrast
(mean, 141 min; standard deviation, 49.8 min) was
significantly longer than that in the group not receiving
oral contrast (mean, 109.2 min; standard deviation,
64.8 min) with a mean difference of 31.8 min
(P<0.0001).
Conclusion: On the basis of our findings and prior
studies, targeted rather than default use of oral contrast
shows acceptable diagnostic ability in the emergency
setting for oncology patients. Benefit from oral contrast
use is suggested in scenarios such as suspected fistula/
bowel leak/abscess, hypoattenuating peritoneal disease,
prior bowel surgery such as gastric bypass, and the
absence of intravenous contrast administration.
Improvement through the use of targeted oral contrast
administration also supports the emergency department
need for prompt diagnosis and disposition.
Key words: Oral contrast—Emergency—
Abdominal—Turnaround time—Bowel
Increasing emergency department (ED) patient volumes
are an ongoing issue that can result in long waiting times
Correspondence to: Corey T. Jensen; email: cjensen@mdanderson.org
ª
Springer Science+Business Media New York 2017
Abdominal
Radiology
Abdom Radiol (2017)
DOI: 10.1007/s00261-017-1175-7
and overcrowding. Increased patient volume has led to a
concomitant increase in imaging utilization as imaging
plays an essential role in triaging many of these patients
to determine or exclude a diagnosis and allow for
appropriate patient disposition. Abdominal complaints
including pain, nausea, and vomiting represent common
chief complaints in the ED that often lead to the use of
computed tomography (CT) for further evaluation. This,
typically necessary, imaging step inherently adds to the
time a patient may spend in the ED. In an attempt to
improve ED disposition times and throughput, oral
contrast optimization has been an area of interest [1,2].
Historically, the administration of oral contrast has
been recommended in most CT examinations of the ab-
domen, especially with the use of older-generation
scanners [3]. Even recent data still support the use of oral
contrast. Kammerer et al. reported that with positive
oral contrast, the odds of a diagnostic improvement are
4.66 times higher (95%confidence interval [CI]
1.36–15.97, P= 0.0144) than with no oral contrast. The
probability of a diagnostic improvement from the use of
neutral oral contrast is increased by an odds ratio of 4.63
(95%CI 1.35–15.87, P= 0.7470) [4]. However, other
studies have recently shown that diagnostic ability can be
maintained without oral contrast in certain patient
groups [5,6].
There is evidence for omitting oral contrast from CT
protocols in many scenarios such as renal colic and
major trauma to aid in the rapid diagnosis and treatment
of patients [7,8]. Even long-standing assumptions that
most bowel trauma evaluations benefit from oral con-
trast have been challenged [911]. Oral contrast
extravasation is one of the least sensitive signs for bowel
injury [12,13]. Strong evidence also supports the omis-
sion of oral contrast in other clinical scenarios such as
appendicitis in which maintained diagnostic accuracy has
been shown [14]. Importantly, a large retrospective study
by Harieaswar et al. demonstrated equivalent diagnostic
capability of multidetector CT performed without oral
contrast compared with CT performed with positive oral
contrast for routine oncologic CT follow-up [6]. In an
ED study of patients with acute non-traumatic abdomi-
nal pain, CT without intravenous or oral contrast had an
overall accuracy of 95.6%and a negative predictive value
of 95.1%[15].
While many studies have demonstrated maintained
CT performance without the use of oral contrast in
specific clinical scenarios, there are also known benefits
to neutral and/or no oral contrast. For example, assess-
ing mucosal enhancement (hyper or hypoenhancement)
can be useful in multiple settings for which positive oral
contrast would often preclude this evaluation such as
Crohn disease, bowel ischemia, and hyperenhancing tu-
mors [1619]. These benefits of not using oral contrast
are amplified by the time savings.
The administration of oral contrast typically requires
a 60–90-min delay before imaging to allow for distal
bowel opacification. Huynh et al. reported a difference in
order-to-scan times of 68 min between CT protocols
performed with and without oral contrast [1]. Studies
have shown that eliminating oral contrast can increase
patient throughput and improved overall patient expe-
rience, while maintaining diagnostic accuracy [1,5,8,
20]. In rare instances, beyond the discomfort of drinking
large quantities of liquid, there can even be safety con-
cerns such as contrast allergy when using water-soluble
iodinated contrast and aspiration.
Variable opacification of the gastrointestinal tract is
another limitation when oral contrast is administered.
The cause of this variation is multifactorial, with one
main factor being poor tolerance of oral contrast
resulting in varied degree of intake. In a satisfaction
survey, the administration of oral contrast was rated to
be the least favorite part of a CT examination, even be-
low that of intravenous cannulation [6]. Importantly,
there can also be marked differences in bowel motility
between patients, which contribute to the variable
opacification. Laituri et al. evaluated patients with
appendicitis and revealed that oral contrast did not reach
the region of interest, the terminal ileum, in 30%of pa-
tients [21].
In certain patient cohorts, the administration of oral
contrast remains the preferred protocol. For example,
thin patients with a paucity of intraabdominal fat are a
known group for whom the administration of oral con-
trast is still suggested owing to less inherent separation of
bowel loops [20]. Evaluations for possible anastomotic
leak, fistula, extramural hematoma, or abscess should
typically include positive oral contrast [4,22]. Hypoat-
tenuating peritoneal disease adjacent to bowel loops can
also be difficult to evaluate without oral contrast. Lastly,
cases imaged without intravenous contrast have been
shown to generally benefit from oral contrast adminis-
tration since the soft tissue delineation provided by
intravenous contrast administration is not present [6].
At our institution, a quaternary oncologic center, we
currently perform all ED abdominal imaging studies with-
out oral contrast unless contrast is specifically requested by
the ED clinician. To the best of our knowledge, no prior
evaluations have specifically assessed oral contrast utility in
cancer patients presenting to the emergency department.
The purpose of our study was to retrospectively compare
between studies with and without oral contrast the perfor-
mance of CT and the order to CT examination turnaround
time in this specific patient group.
Materials and methods
This retrospective study was approved by our institu-
tional review board as Health Insurance Portability and
C. T. Jensen et al.: Utility of CT oral contrast administration in the emergency
Accountability Act compliant and the need for informed
consent was waived.
Patient selection
On the basis of a power analysis performed before the
study, we reviewed a contiguous set of patients who
underwent ED CT scanning of the abdomen/pelvis dur-
ing April 2016. This was the first month of patient
scanning after the implementation of a new oral contrast
policy for CT imaging of the abdomen; the previous
default administration of water-soluble, positive oral
contrast was changed to no oral contrast unless re-
quested otherwise by an ED clinician.
The patients’ primary cancer, age, sex, chief com-
plaint/examination indication, body mass index, and
disposition from the ED were recorded. For each CT
examination, the presence or absence of intravenous and
oral contrast was noted and was compared with the
original physician order. The official radiology reports
were reviewed to identify any comments made as to
perceived limitations of the study, particularly those re-
lated to the presence or absence of oral contrast. A re-
cord was made if a patient underwent additional CT
scanning that included the abdomen/pelvis within
4 weeks of the incident scan.
Imaging technique
All patients underwent CT of the abdomen/pelvis with
an identical imaging protocol performed on a 128-slice
dual-source CT system (Somatom Definition Flash;
Siemens Healthineers, Erlangen, Germany) with gantry
speed of 0.5 s, pitch of 0.6:1, table speed of 23 mm/ro-
tation, beam collimation of 38.4 mm with detector con-
figuration of 128 90.6 mm, and 120 kVp using tube
current modulation. When intravenous contrast was or-
dered, 125 mL of Omnipaque 350 (GE Healthcare,
Chicago, IL) was injected at 2.5–3 mL/sec with bolus
tracking using a Hounsfield unit trigger value of 100 in
the abdominal aorta at the level of the celiac artery and a
scan delay of 45 s. When oral contrast was ordered,
40 mL of Omnipaque 350 was mixed into water for a
total administration of 800 mL with a target scan time of
approximately 60 min after the start of administration.
Imaging review
Three-millimeter axial image sets were used for primary
review (2-mm coronal and sagittal reconstructions were
available for correlation) using a picture archiving and
communication system diagnostic reading station with
two consensus readers in a non-blinded, randomized
fashion over 10 sessions. Each reader was fellowship-
trained in abdominal imaging with 5 subsequent years
(C.J.) and 6 subsequent years (N.W.-B.) of experience
reading abdominal CT. No time limit was set for review.
A five-point Likert scale was used by the readers to
qualitatively grade the impact of enteric contrast status
on confidence and on diagnosis as follows: 5, Definitely
Improved; 4, Improved; 3, No Consequence; 2, Im-
paired; 1, Definitely Impaired. A score of 5 for a patient
with oral contrast indicated that the readers felt that the
presence of oral contrast definitely improved diagnosis or
confidence. For a case without oral contrast, however, a
score of 5 indicated that the absence of oral contrast
definitely improved diagnosis or confidence. When
assessing confidence, factors such as the degree with
which oral contrast status affected mucosal detail, ana-
tomic delineation such as separation of bowel loops from
adjacent anatomy, and delineation of pathology (when
applicable) were used as criteria during scoring.
Readers utilized studies performed before and after
the scan of interest and any available clinical notes in
their assessment.
Turnaround time assessment
The electronic medical record was queried for CT order
time and examination start time to calculate the turn-
around time between the order and the oral contrast
administration.
Statistical analysis
Patient and imaging characteristics were summarized
using mean, standard deviation (SD), and range. Pearson
Chi square test, Fisher exact test, and two-sample ttest
were used to assess the associations of oral contrast,
patient disposition, and whether CT was repeated within
4 weeks status with other covariates. All tests were two-
sided, and P-values of 0.05 or less were considered sta-
tistically significant. Statistical analysis was carried out
using SAS version 9.3 (SAS Institute, Cary, NC).
Results
Patient characteristics
The studied group consisted of 267 patients (127 men
and 140 women) with a mean age of 56 years (range
19–57 years). Mean body mass index was 27.8 kg/m
2
(range 12.8-59.5 kg/m
2
). One hundred and sixty CT
examinations were performed without oral contrast, and
107 CT examinations were performed with oral contrast.
Forty-one CT examinations were performed without
intravenous contrast and 226 CT examinations were
performed with intravenous contrast. One hundred and
ninety-seven of the patients were admitted to the inpa-
tient service, and the other 70 were discharged home. The
top three diagnoses were breast cancer, colon cancer, and
leukemia, and the top three chief complaints were
C. T. Jensen et al.: Utility of CT oral contrast administration in the emergency
abdominal pain, nausea, and vomiting. No significant
correlation was identified between age, sex, body mass
index, chief complaint, cancer diagnosis, disposition
status, or repeat CT examination.
Turnaround times
The turnaround time in the group receiving oral contrast
(mean, 141 min; SD, 49.8 min) was significantly longer
than in the group not receiving oral contrast (mean,
109.2 min; SD, 64.8 min), with a mean difference of
31.8 min (P<0.0001).
ED physician ordering
Of the 267 patients, the ED physician requested oral
contrast for 88 patients, requested no oral contrast for 93
patients, and made no comment in 86 patients; for cases
without such a comment, our current default protocol is
to use no oral contrast. Brief review of ED ordering in
the subsequent 2 months revealed 88 and 69 requests,
respectively, for oral contrast; 58 and 56 specific requests,
respectively, for no oral contrast; and 104 and 129 cases,
respectively, in which no specific comment was made in
the order regarding oral contrast. Following the oral
contrast protocol requested by the EC physician, only six
patients were identified as inferior in reader confidence
and/or diagnosis. In the five patients without oral con-
trast, limitations were related to cachexia, peritoneal
implant mimicking small bowel, matted tumor in the
pelvis, fistula, and two cases that were performed without
intravenous contrast, one of which had peritoneal disease
from colon carcinoma. In the one patient with oral
contrast that was rated to be inferior, there was peri-
toneal disease in a patient with endometrial carcinoma.
Imaging review
For patients not receiving vs. receiving oral contrast,
there were more cases rated as impaired confidence (6
cases:1 case) (Odds ratio (OR) 3.92, 95%Confidence
Interval (CI) 0.46–33.06, P= 0.21) and impaired diag-
nosis (4:1) (OR 2.63, 95%CI 0.29–23.89, P= 0.39) in
relation to ratings of no consequence. Conversely, there
were fewer cases rated as improved confidence (10:12)
(OR 0.54, 95%CI 0.23–1.31, P= 0.17) and improved
diagnosis (7:8) (OR 0.58, 95%CI 0.20–1.64, P= 0.3) in
relation to ratings of no consequence. For patients not
receiving vs. receiving oral contrast in relation to im-
paired vs. improved cases, there also was no statistical
Fig. 1. Reader scores for
the impact of oral contrast
status on confidence
(A) and diagnosis (B)inCT
scans. Enteric contrast
status was of no
consequence in the
overwhelming majority of
cases.
C. T. Jensen et al.: Utility of CT oral contrast administration in the emergency
significance for confidence (OR 7.20, 95%CI 0.74–70.20,
P= 0.089) or diagnosis (OR 4.57, 95%CI 0.41–51.1,
P= 0.22) (Fig. 1).
For patients not receiving intravenous contrast vs.
those receiving intravenous contrast, controlling for oral
contrast status, there were more cases rated as impaired
confidence (P= 0.0169) and impaired diagnosis
(P<0.0014) when no oral contrast was administered. No
significant difference between intravenous contrast grou ps
was identified when oral contrast was administered.
Cross-tabulations were performed on each cancer
type with sample size greater than or equal to 5 with
respect to reader scores; there were 18 cancer types that
were assessed: bladder, endometrial, colon, lymphoma,
leukemia, breast, carcinoma of unknown primary, cer-
vical, cholangiocarcinoma, gastric, lung, melanoma,
neuroendocrine, ovarian, pancreatic, prostate, renal, and
sarcoma. No significant correlations were identified
through cross-tabulations.
Four scans were specifically described as suboptimal in
the radiology report owing to lack of oral contrast; these
cases were of typhlitis, obstructive uropathy, parastomal
hernia with possible strangulation, and progression of
peritoneal disease. Lack of oral contrast for these four
studies was rated as ‘‘no consequence’’ except for the last
case, which notably was performed without intravenous
contrast. Readers rated that case as ‘‘likely impaired.’’ In the
radiology reports of these 4 scans, only the case of typhlitis
described a specific limitation which was due to the absence
of positive oral contrast precluding fistula assessment.
Fifty-two patients underwent CT examination within
4 weeks after the incident scan. Every scan reviewed had
a prior or subsequent study for comparison. No missed
findings by the original reader related to the status of
oral contrast were identified during imaging review.
Discussion
Our study evaluated an oncologic population presenting
to the emergency department who underwent CT of the
abdomen for abdominal complaints; no statistical dif-
ference in reader confidence or diagnosis was identified
related to whether or not patients received oral contrast
and there was a significant reduction in turnaround time
for patients without oral contrast. This is in agreement
with prior studies that have evaluated other patient
populations [1,2,6,14].
Previous studies of CT oral contrast have been nar-
row in scope, focusing primarily on trauma, renal colic,
and appendicitis [1,2,4,17,18,20]. Some evaluations
Fig. 2. Intravenous
contrast-enhanced CT
examination examples from
various patients in our study
demonstrate the benefits of
not having positive oral
contrast. Gastric wall
thickening with differential
enhancement (A), small
bowel thickening with
mucosal hyperenhancement
(B), hypervascular
metastasis to the small
bowel from renal cell
carcinoma (C), and sarcoma
metastases (D) are
scenarios where no oral
contrast or neutral contrast
can be helpful (arrows).
C. T. Jensen et al.: Utility of CT oral contrast administration in the emergency
have studied outpatient and undifferentiated oncologic
patient groups with mixed results [4,6]. Harieaswar et al.
[6] audit of 447 patients presenting for oncologic follow-
up revealed 94.9%of studies to be deemed adequate
without oral contrast; when correlating the other cases
with follow-up, only 1.6%of cases were ultimately clas-
sified as ‘‘bowel not clearly identified.’’
In our study, while most cases of oral contrast status
were rated as ‘no consequence,’ similar benefits and
limitations of using and withholding oral contrast were
identified. For example, without oral contrast, readers
noted that bowel enhancement, certain cases of bowel
wall thickening, surgical clips, hemorrhage, and hyper-
enhancing bowel/peritoneal tumors were better seen
(Figs. 2and 3). It is possible that, had these cases been
performed with oral water, improvement may have been
seen relative to positive oral contrast, as described by
Krammerer et al. [4]. Conversely, cases of matted tumor,
post-operative cases involving the bowel, fistulas, leaks,
certain duodenal stents, perforations, and hypoattenu-
ating bowel/peritoneal tumors were limited in their
evaluation by the lack of oral contrast and were generally
better evaluated with oral contrast (Fig. 4). Additionally,
as described by Harieaswar et al., examinations in which
intravenous contrast is otherwise contraindicated often
benefit from the administration of oral contrast [6]. Some
lesions were seen similarly in cases with and without oral
contrast (Fig. 5).
Importantly, in addition to considerations of diag-
nostic accuracy and timeliness, the limitations of oral
contrast should be understood. One of the most frequent
limitations that has been reported and that we noted was
the variable distribution of administered oral contrast; a
patient in our study who waited over an hour during the
administration of oral contrast still did not have oral
contrast at the site of bowel fistula in the pelvis and
another patient with a bowel leak did not have oral
contrast reach the site of interest. Much of this variation
likely relates to differences in bowel transit between pa-
tients and is at least partially influenced by patient tol-
erance of oral contrast [6,21]. In the literature and in our
study, positive oral contrast has obscured lesions
including primarily hyperenhancing bowel/peritoneal
implants and hematomas, and it generally precludes the
assessment of bowel wall enhancement [16].
Our study, similar to prior reports, showed a de-
creased order to examination turnaround time for pa-
tients not receiving oral contrast compared with those
receiving contrast. CT examinations without oral con-
trast were performed a mean of 31.8 min earlier from
time of order entry than those receiving oral contrast.
This amount of time is less than our protocol-targeted
delay of 60 min after start of oral contrast. Variation in
this timing points to the complexity of the ED care
pathway. Wang et al. detailed the complex process of
length of stay and turnaround time assessments [2].
While the above-mentioned time savings are desired if
the diagnostic performance is adequate, patients clearly
have varied transit pathways through the ED, and a
more detailed analysis would likely be useful.
Though not explored in this study, keeping radiation
dose as low as reasonably achievable should be considered
in relation to oral contrast. Wang et al. demonstrated that
patients receiving positive oral contrast had a volume CT
dose index that was 11%higher than that of patients
receiving oral water alone [23]. While the significance of
this dose savings will vary depending on patient age and
clinical status, it remains important to note as another
benefit of foregoing positive oral contrast.
The limitations of our study include the retrospective
design, but importantly, our findings agree with most
prior studies. Consensus reading has inherent limitations
Fig. 3. A metastatic implant in the midabdomen contained
hyperdense active hemorrhage (arrow) and was associated with
a hematocrit level (dashed arrow)(A). A CT examination per-
formed 7 days earlier demonstrated multiple findings, but oral
contrast obscured this lesion that was likely already bleeding,
thus producing a hyperdense appearance (arrow)(B).
C. T. Jensen et al.: Utility of CT oral contrast administration in the emergency
as well, but use of the official radiology report and
prior/subsequent CT examinations were helpful to sup-
plement evaluation. The goal of this study was to assess
our new policy in which oral contrast administration is
no longer the default in ED CT scanning of the abdo-
men/pelvis; thus, there was an inherent bias in the study
population based on variation in ED physician requests
for oral contrast. ED physician ordering is generally in
agreement with our radiology department recommen-
dations that patients with suspected bowel pathology
including fistula, abscess, or leak receive positive oral
contrast; however, there is certainly variation in these
orders. Lastly, consensus evaluation infers significance,
or lack thereof, based on knowledge of known benefits
and limitations of oral contrast; for example, the authors
may have rated a case with positive oral contrast as ‘‘no
consequence,’’ but it is not possible to know whether
underlying mucosal hyperenhancement was been present.
This limitation was mitigated by detailed review of cur-
rent and follow-up clinical notes, review of pertinent
prior, and subsequent scans, and the attempt to identify
other features such as bowel wall thickening in the case
of potentially obscured mucosal hyperenhancement.
On the basis of our findings and prior studies, tar-
geted rather than default use of oral contrast shows
acceptable diagnostic ability in the emergency setting for
oncology patients. Benefit from oral contrast use is
suggested in scenarios such as suspected fistula/bowel
leak/abscess, hypoattenuating peritoneal disease, prior
bowel surgery such as gastric bypass, and the absence of
intravenous contrast administration. Improvement
through the use of targeted oral contrast administration
Fig. 4. Examples of CT examinations from our study per-
formed in three different patients demonstrate the benefits of
oral contrast administration. In the first patient (A,B), a duo-
denal perforation was confirmed by the extravasation of oral
contrast (arrow). Two other patients (CF) underwent CT
examinations that were performed within a short time period
of one another, one without oral contrast and the other with
oral contrast. In each case, a diagnosis of tumor fistula with
bowel was directly identified only on the examinations with
oral contrast (arrows).
C. T. Jensen et al.: Utility of CT oral contrast administration in the emergency
also supports the emergency department need for prompt
diagnosis and disposition. While some of the above
conditions that may benefit from positive oral contrast
may not always be suspected clinically during ordering
and thus may not receive such contrast, it appears that
more cases will benefit from discriminant oral contrast
use. Certainly other nuances of protocols can be con-
sidered, such as shorter administration time of oral
contrast. Further prospective evaluations of oral contrast
protocols are needed.
Compliance with ethical standards
Funding This study was supported by institutional CCSG (cancer
center support Grant) from the NIH/National Cancer Institute under
award number P30CA016672.
Conflict of interest The authors declare that they have no conflict of
interest.
Ethical approval All procedures performed in studies involving human
participants were in accordance with the ethical standards of the
institutional and/or national research committee and with the 1964
Helsinki declaration and its later amendments or comparable ethical
standards. For this type of study formal consent is not required.
Informed consent This retrospective study was approved by our insti-
tutional review board as Health Insurance Portability and Accountability
Act compliant and the need for informed consent was waived.
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C. T. Jensen et al.: Utility of CT oral contrast administration in the emergency
... This could be translated to an estimated $18.18 (USD) in savings per single CT requiring enteric contrast. Meanwhile, studies have reported a time delay of 60 to 90 minutes following oral contrast administration for optimal distal bowel opacification (37). These studies have also found an improved examination completion rate and overall patient experience through the elimination of oral contrast use (36,37). ...
... Meanwhile, studies have reported a time delay of 60 to 90 minutes following oral contrast administration for optimal distal bowel opacification (37). These studies have also found an improved examination completion rate and overall patient experience through the elimination of oral contrast use (36,37). Finally, previous studies on blunt abdominal trauma have suggested the use of enteric contrast may preclude assessment of the bowel mucosa for enhancement, which may also be the case in penetrating trauma (9,39). ...
Article
Background: Scarce evidence exists on the diagnostic benefit of enteric contrast for abdominopelvic CT performed in the setting of penetrating trauma. Objectives: The purpose of this systematic review and meta-analysis is to compare the diagnostic accuracy of CT using enteric contrast, with that of CT not using enteric contrast, in penetrating traumatic abdominopelvic injury in adults. Evidence Acquisition: A protocol was registered a priori (PROSPERO CRD42019139613). MEDLINE and EMBASE were searched until June 25, 2019. Studies were included that evaluated the diagnostic accuracy of abdominopelvic CT either with or without enteric (oral and/or rectal) contrast in patients presenting with penetrating traumatic injury. Relevant study data metrics and risk of bias were assessed. Bivariate random-effects meta-analyses and meta-regression modeling were performed to assess and compare diagnostic accuracies. Evidence Synthesis: From an initial sample of 829 studies, 12 studies were included that reported on 1,287 patients with penetrating injury (389 with confirmed bowel, mesenteric, or other abdominopelvic organ injury). The enteric contrast group (seven studies; 506 patients, 124 with confirmed penetrating injury) demonstrated a sensitivity of 83.8% (95% confidence interval [CI], 73.7%, 90.5%) and specificity of 93.8% (95% CI, 83.6%, 7.8%). The non-enteric contrast group (six studies; 781 patients, 265 with confirmed penetrating injury) demonstrated a sensitivity of 93.0% (95% CI, 86.8%, 96.4%) and a specificity of 90.3% (95% CI, 81.4%, 95.2%). No statistically significant difference was identified for sensitivity (p=0.07) or specificity (p=0.37) between the enteric and non-enteric contrast groups based on meta-regression. Nine of 12 studies demonstrated risk of bias in at least one QUADAS-2 domain (most frequently limited reporting of blinding of radiologists or lack of blinding of radiologists, insufficient clinical follow-up for the reference standard, and limited reporting of sampling methods). Conclusions: The use of enteric contrast for CT does not provide a significant diagnostic benefit for penetrating traumatic injury. Clinical Impact: Eliminating enteric contrast for CT in penetrating traumatic injury can prevent delays in imaging and surgery, as well as reduce cost.
... This could be translated to an estimated $18.18 (USD) in savings per single CT requiring enteric contrast. Meanwhile, studies have reported a time delay of 60 to 90 minutes following oral contrast administration for optimal distal bowel opacification (37). These studies have also found an improved examination completion rate and overall patient experience through the elimination of oral contrast use (36,37). ...
... Meanwhile, studies have reported a time delay of 60 to 90 minutes following oral contrast administration for optimal distal bowel opacification (37). These studies have also found an improved examination completion rate and overall patient experience through the elimination of oral contrast use (36,37). Finally, previous studies on blunt abdominal trauma have suggested the use of enteric contrast may preclude assessment of the bowel mucosa for enhancement, which may also be the case in penetrating trauma (9,39). ...
Article
Background: Transarterial chemoembolization (TACE) has synergistic properties when combined with ablative therapies for hepatocellular carcinoma (HCC). Objective: To compare outcomes for inoperable HCC between TACE with percutaneous thermal ablation (T-TA) and TACE with stereotactic body radiotherapy (T-SBRT) using propensity-score-weighted cohorts. Methods: This retrospective study included 190 patients with a single inoperable HCC treated from 2007 to 2018 by either T-SBRT (n=90) or T-TA (n=100). The primary outcome was overall survival (OS). Secondary outcomes included progression-free survival (PFS) and hepatotoxicity (defined as Child Pugh elevation of ≥ 2 within two to six months post-treatment). Fine-Gray competing risk models with propensity score weighting and transplantation as the competing risk factor were used to model OS and PFS. Results: The median follow-up time was 48.2 months. OS and PFS were both significantly higher for T-TA (77% and 76%, respectively, at 2 years) than T-SBRT (49% and 50%, respectively, at 2 years) in the propensity weighted multivariate model (OS: subdistributed hazard ratio [sHR] 2.70, p<0.001; PFS: sHR: 1.71, p=0.016). Treatment-related hepatotoxicity occurred in 9% for T-TA vs. in 27% for T-SBRT (p=0.010). For the subset of patients with Barcelona Clinic Liver Cancer A HCC and Child-Pugh A cirrhosis (T-SBRT [n=36], T-TA [n=55] T-TA), OS (p=0.108) and PFS (p=0.189) were not significantly different between the two treatment modalities. Conclusion: Compared to T-SBRT, T-TA demonstrated superior OS and PFS, possibly from lesser hepatotoxicity. The two strategies did not differ in OS and PFS in patients with the earliest-stage HCC and preserved liver function. Clinical impact: Across all patients, T-TA may be superior to T-SBRT for inoperable HCC.
... Due to the broad and potentially insidious etiology of acute abdominal pain, early and accurate diagnosis is essential to avoid misclassification and treatment error [2]. Consequently, computed tomography (CT) is frequently performed, historically with administration of both positive oral contrast media (POCM) and intravenous (IV) contrast media [3][4][5]. ...
Article
Full-text available
Objective Evaluate the impact of positive oral contrast material (POCM) for non-traumatic abdominal pain on diagnostic confidence, diagnostic rate, and ED throughput. Materials and methods ED oral contrast guidelines were changed to limit use of POCM. A total of 2,690 abdominopelvic CT exams performed for non-traumatic abdominal pain were prospectively evaluated for diagnostic confidence (5-point scale at 20% increments; 5 = 80–100% confidence) during a 24-month period. Impact on ED metrics including time from CT order to exam, preliminary read, ED length of stay (LOS), and repeat CT scan within 7 days was assessed. A subset of cases (n = 729) was evaluated for diagnostic rate. Data were collected at 2 time points, 6 and 24 months following the change. Results A total of 38 reviewers were participated (28 trainees, 10 staff). 1238 exams (46%) were done with POCM, 1452 (54%) were performed without POCM. For examinations with POCM, 80% of exams received a diagnostic confidence score of 5 (mean, 4.78 ± 0.43; 99% ≥ 4), whereas 60% of exams without POCM received a score of 5 (mean, 4.51 ± 0.70; 92% ≥ 4; p < .001). Trainees scored 1,523 exams (57%, 722 + POCM, 801 -POCM) and showed even lower diagnostic confidence in cases without PCOM compared with faculty (mean, 4.43 ± 0.68 vs. 4.59 ± 0.71; p < 0.001). Diagnostic rate in a randomly selected subset of exams (n = 729) was 54.2% in the POCM group versus 56.1% without POCM (p < 0.655). CT order to exam time decreased by 31 min, order to preliminary read decreased by 33 min, and ED LOS decreased by 30 min (approximately 8% of total LOS) in the group without POCM compared to those with POCM (p < 0.001 for all). 205 patients had a repeat scan within 7 days, 74 (36%) had IV contrast only, 131 (64%) had both IV and oral contrast on initial exam. Findings were consistent both over a 6-month evaluation period as well as the full 24-month study period. Conclusion Limiting use of POCM in the ED for non-traumatic abdominal pain improved ED throughput but impaired diagnostic confidence, particularly in trainees; however, it did not significantly impact diagnostic rates nor proportion of repeat CT exams. Graphical abstract
... Also, delineation of ovaries from nonopacified bowel loops can be difficult in lean children. At the same time, some recent studies have argued against the benefits of oral contrast during CT of the abdomen and pelvis for different reasons [6][7][8]. The choice between MRI and CT should take into account the need to sedate and the radiation risk. ...
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Full-text available
The spectrum of ovarian tumors in the pediatric population differs significantly from that in adults. Germ cell tumors are the predominant class of ovarian tumors in children, whereas epithelial tumors are the most common in adults. Ultrasonography is the modality of choice for the initial evaluation of pediatric ovarian tumors. Determining the diagnosis based on imaging may prove difficult, and combining the imaging findings with the clinical scenario is very helpful in reaching a differential diagnosis during clinical practice. We will discuss the spectrum of ovarian neoplasms in the pediatric population and describe their clinical, pathologic, and imaging characteristics. A few unique entities related to ovarian tumors, such as growing teratoma syndrome, anti–N-methyl-d-aspartate receptor encephalitis, and hereditary ovarian tumor syndromes, are also discussed. In addition, we will review several entities that may mimic ovarian neoplasms as well as their distinct imaging features.
Chapter
Ovarian cancer usually affects postmenopausal females and is sporadic in 90% of cases. It remains the deadliest gynecologic cancer. Although tumors originating in the ovary, fallopian tube, and covering peritoneum fall under this category, their staging/prognosis may defer. Epithelial tumors account for 90% of ovarian malignancy overall. Other types of ovarian tumors include germ cell tumors, being most common in young females, and exemplified by cystic teratoma; and sex cord-stromal tumors, exemplified by granulosa cell tumor that is known for hormonal secretion. The role of screening in detecting ovarian cancer is still limited and controversial; and imaging is no different. The FIGO staging system was revised in 2014, with modification of the substages and definitions so to reflect current understanding and advances. The most common mode of ovarian cancer spread is intraperitoneal, and approximately 70% of patients have peritoneal metastases at staging laparotomy. The primary role of imaging in ovarian neoplasia is to detect the mass, identify malignancy features, and predict spread. MRI and PET/CT–in particular–have the greatest role in detecting recurrence. Management is a combination of staging cytoreductive surgery and chemotherapy. Some improvement in median survival time has been achieved over the last 3 decades, however the overall prognosis–particularly for patients presenting beyond stage II–remains unfavorable.
Article
Background: Data are limited regarding utility of positive oral contrast material for peritoneal tumor detection on CT. Objective: To compare positive versus neutral oral contrast material for detection of malignant deposits in nonsolid intraabdominal organs on CT. Methods: This retrospective study included 265 patients (133 men, 132 women; median age, 61 years) who underwent an abdominopelvic CT examination where the report did not suggest presence of malignant deposits and subsequent CT examination within 6 months where the report indicated at least one unequivocal malignant deposit. Examinations used positive (iohexol; n=100) or neutral (water; n=165) oral agents. A radiologist reviewed images to assess whether the deposits were visible (despite clinical reports indicating no deposits) on unblinded comparison with the follow-up examinations; identified deposits were assigned to one of seven intraabdominal compartments. The radiologist also assessed adequacy of bowel filling with oral contrast material. Two additional radiologists independently reviewed examinations in blinded fashion for malignant deposits. NPV was assessed of clinical CT reports and blinded retrospective readings for detection of malignant deposits visible on unblinded comparison with follow-up examinations. Results: Unblinded review identified malignant deposits in 58.1% (154/265) of examinations. In per-patient analysis of clinical reports, NPV for malignant deposits was higher for examinations with adequate bowel filling with positive oral contrast material [65.8% (25/38)] than for examinations with inadequate bowel filling with positive oral contrast material [45.2% (28/62]], p=.07) or with neutral oral contrast material regardless of bowel filling adequacy [35.2% (58/165), p=.002]. In per-compartment analysis of blinded interpretations, NPV was higher for examinations with adequate and inadequate bowel filling with positive oral contrast material than for examinations with neutral oral contrast regardless of bowel filling adequacy [reader 1: 94.7% (234/247) and 92.5% (382/413) vs 88.3% (947/1072), both p=.045; reader 2: 93.1% (228/245) and 91.6% (361/394) vs 85.9% (939/1093), both p=.01]. Conclusion: CT has suboptimal NPV for malignant deposits in intraabdominal nonsolid organs. Compared to neutral material, positive oral contrast material improves detection, particularly with adequate bowel filling. Clinical Impact: Optimization of bowel preparation for oncologic CT may help avoid potentially severe clinical consequences of missed malignant deposits.
Article
Abdominal pain represents 5% to 7% of all emergency department presentations. Many patients require imaging for diagnosis, and choosing the appropriate imaging modality is a crucial decision point. Modern medicine offers a fantastic array of options including abdominal radiograph, computed tomography, MRI, and ultrasonography, but the plethora of alternatives can be paralyzing. This article introduces the commonly available modalities, discusses the advantages and disadvantages, and presents current recommendations for commonly diagnosed conditions.
Article
Background: The value of dual-energy CT (DECT) for bowel wall assessment is increasingly recognized. While technical improvements have been shown to reduce peristalsis artifact in conventional CT, the effects of peristalsis on DECT image reconstructions remain poorly studied. Objectives: To evaluate the influence of different DECT scanners and enteric contrast agents on the severity of bowel peristalsis artifact in vitro. Methods: To simulate bowel peristalsis, a 3-cm diameter corrugated hollow "bowel" tube was oscillated constantly in z-axis within a larger water-filled cylinder. The bowel was serially filled with air, water, and iodinated or experimental dark contrast material and scanned on four different DECT platforms (spectral-detector, rapid-kVp-switching, split-filter and dual-source) to reconstruct 120-kVp-like and iodine images. Two readers rated each image reconstruction for artifact severity from 0 (none) to 3 (severe) and recorded the ability of iodine images to reveal bowel wall hyperattenuation on 120-kVp-like images as artifactual. Artifact severity scores were compared using ANOVA with Bonferroni correction. Results: Interrater agreement for artifact scores was excellent, with intraclass correlation coefficient (ICC) of 0.82 [95%-CI: 0.79-0.84]. For 120-kVp-like images, mean peristalsis artifact scores were lower (all p<.001) for split-filter (1.47) and dual-source (1.86) scanners than for spectral-detector (2.58) or rapid-kVp-switching (2.74) scanners. Compared with 120-kVp images, peristalsis artifacts for iodine images were lower for spectral-detector (1.03, p<.001) and rapid-kVp-switching (2.09, p<.001), but more severe for dual-source (2.77, p<.001) and split-filter (2.62, p<.001) systems. Peristalsis artifact was minimized by use of experimental dark bowel contrast (1.79) compared to other bowel contrast agents (all p<.001). Iodine images helped identify bowel wall hyperattenuation as artifactual in 94.6% and 40.7% of reviewed cases for spectral-detector and rapid-kVp-switching scanners, respectively. Conclusions: For spectral-detector and rapid-kVp-switching DECT, iodine images minimize peristalsis artifact, but for dual-source and split-filter DECT, mixed 120-kVp-like images are preferred. Experimental dark bowel contrast material reduces peristalsis artifact compared to iodinated contrast material or water. Clinical impact: Knowledge of the preferred images to reduce peristalsis artifact can lessen the impact of peristalsis on clinical dual-energy CT interpretation. Dark enteric contrast agents, once clinically available, may further reduce the effects of peristalsis.
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The pattern of disease causing acute abdominal pain has changed over last few decades, some of this has been attributed to intraabdominal cancers. The most common acute abdominal complaints in cancer patients are related to the gastrointestinal system. Abdominal emergencies in cancer patients can result from the underlying malignancy itself, cancer therapy and/or result from the standard pathologies causing acute abdomen in otherwise healthy population. Therapy-related or disease-related immunosuppression or high dose analgesics often blunt many of the findings which are usually expected in non-cancer general population. This complicates the clinical picture rendering the clinical exam less reliable in many cancer patients, and resulting in different pathologies which clinicians and the radiologists should remain aware of. This article focuses on imaging illustrations with differential diagnosis for various emergency scenarios related to acute abdomen specifically in oncologic settings.
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Trauma affects all sociodemographic profiles and is a major cause of morbidity and mortality particularly in patients less than forty years of age. A variety of endoscopic tools and techniques initially used for iatrogenic etiologies (post-operative bile or pancreatic duct leaks, intra-procedural perforation) have been adopted for use in the gastrointestinal trauma victim. The purpose of this review is to highlight a variety gastrointestinal traumatic complications where endoscopy can serve a complement and/or definitive management strategy.
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High body mass index (BMI) values generally correlate with a large proportion of intra-peritoneal adipose tissue. Because intra-peritoneal infectious and inflammatory conditions manifest with abnormalities of the adipose tissue adjacent to the inflamed organ, it is presumed that with a larger percentage of adipose surrounding a given organ, visualization of the inflammatory changes would be more readily apparent. Do higher BMI values sufficiently enhance the ability of a radiologist to read a computed tomography (CT) of the abdomen and pelvis, so that the need for oral contrast to be given is precluded? FORTY SIX PATIENTS WERE INCLUDED IN THE STUDY: 27 females, and 19 males. They underwent abdominal/pelvic CTs without oral or intravenous contrast in the emergency department. Two board certified radiologists reviewed their CTs, and assessed them for radiographic evidence of intra-abdominal pathology. The patients were then placed into one of four groups based on their body mass index. Kappa analysis was performed on the CT reads for each group to determine whether there was significant inter-rater agreement regarding contrast use for the patient in question. There was increasingly significant agreement between radiologists, regarding contrast use, as the study subject's BMI increased. In addition, there was an advancing tendency of the radiologists to state that there was no need for oral or intravenous contrast in patients with higher BMIs, as the larger quantity of intra-peritoneal adipose allowed greater visualization and inspection of intra-abdominal organs. Based on the results of this study, it appears that there is a decreasing need for oral contrast in emergency department patients undergoing abdominal/pelvic CT, as a patient's BMI increases. Specifically, there was statistically significant agreement, between radiologists, regarding contrast use in patients who had a BMI greater than 25.
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The purpose of this study is to calculate the negative predictive value (NPV) CT of the abdomen in patients presenting to the emergency department (ED) with undifferentiated upper abdominal pain. Approved by the hospital research ethics board, this retrospective study examined consecutive patients presenting to the ED with undifferentiated upper abdominal pain whose intravenous contrast-enhanced CT of the abdomen was reported as "normal" from June 2006-August 2010. Exclusion criteria included active malignancy, trauma, and known inflammatory bowel disease. True-negative (TN) vs. false-negative (FN) cases were categorized by consensus opinion of radiologist and emergency physician using a composite reference standard including clinical, laboratory, imaging, surgery, pathology, and patient self-reporting via phone questionnaire. The NPV was calculated with confidence intervals of 95%. The TN and FN groups were compared based on gender, age, site of pain, oral contrast use, and laboratory values. One hundred twenty-seven patients were included for analysis. The NPV was 64% (95% CI 55-72). The FN group had a higher proportion of patients with epigastric pain (p = 0.02) and a lower proportion of patients with left upper quadrant pain (p = 0.02). The WBC, lipase, and ALT were all higher in the FN group compared with the TN group. The most commonly missed pathologies were inflammatory conditions of the biliary tract and upper gastrointestinal systems. The NPV of CT for evaluation of undifferentiated upper abdominal pain in the ED was low at 64%. Physicians should consider this limitation and the commonly missed pathology when discharging patients with a "normal" CT report.
Article
Objective: The purpose of this study was to quantify and integrate key emergency department (ED) and radiology department workflow time intervals within the ED length of stay (LOS) for patients presenting with acute abdomen who require CT. Materials and methods: An 11-month retrospective review was performed of all patients presenting to the ED with an acute abdomen who required abdominal CT. Nine key time points associated with ED LOS and CT workflow were collected: triage, physician assessment, CT request, porter schedule, CT start, CT complete, provision of first CT report, ED disposition decision, and physical discharge. The median and 90th percentile times for each interval were reported. Results: Ninety-six percent (2194/2292) of ED encounters during the study period met the inclusion criteria. The median ED LOS was 9.22 hours (90th percentile, 15.7 hours). Intervals associated with CT workflow accounted for 29% of the total LOS. Radiology turnaround time accounted for 32% of the entire CT workflow interval. Timeline analysis found three unique patterns of ED disposition: disposition after initial imaging report, disposition before report, and disposition before CT. Conclusion: To our knowledge, this study is the first to quantify the contribution of CT-related workflow time intervals within the context of ED LOS. We have shown that patients do not have identical ED transit pathways, and this may under- or overestimate time interval calculations. These results show the importance of site-specific ED LOS timeline analysis to identify potential targets for quality improvement and serve as baseline targets for measuring future quality improvement initiatives.
Article
Hypothesis Oral contrast solution (OC) is unnecessary in the acute computed tomographic (CT) evaluation of the patient with blunt abdominal trauma.Design Randomized controlled clinical trial.Setting Level I trauma center at a university-affiliated teaching hospital.Patients Five hundred adult patients sustaining blunt abdominal trauma and requiring urgent resuscitation and CT evaluation of the abdomen were eligible for the study. Those patients who were younger than 18 years, pregnant, or in police custody were excluded. One hundred six patients were excluded from the analysis (15 for inappropriate enrollment, 9 because a CT scan had not been performed, 1 owing to inability to accept a nasogastric tube, and 81 owing to missing or incomplete records). Three hundred ninety-four patients with an average age of 36 years, an average Revised Trauma Score of 10, and an average Glasgow Coma Scale score of 12 are included in the analysis.Interventions Patients were randomized via computer-generated assignment to 1 of 2 groups either receiving OC or not receiving OC (no OC) after placement of a nasogastric tube. All patients received intravenous contrast solution and then underwent helical CT scan of the abdomen and pelvis using the GE HiSpeed Advantage CT scanner (GE Medical Systems, Milwaukee, Wis).Main Outcome Measures Abnormal CT results, need for laparotomy, missed gastrointestinal tract and solid organ injuries, nausea, and vomiting.Results There were 199 patients in the OC group and 195 patients in the no OC group. Vomiting occurred in 12.9% of patients and the incidence was not different between groups. One hundred five abnormal scans (50 OC and 55 no OC) were obtained and 33 patients with abnormal scans (19 OC and 14 no OC) underwent laparotomy. There was 1 nontherapeutic laparotomy in each group. There was 1 missed small-bowel injury in the OC group (sensitivity, 86%) and no missed small-bowel injuries in the no OC group (sensitivity, 100%). Six bowel injuries were identified at laparotomy in the OC group. Two of the injuries were perforations without contrast extravasation but with pneumoperitoneum in 1. Three bowel injuries were identified in the no OC group, none of which were perforations. Seven of the 9 patients with bowel injury at laparotomy had associated intra-abdominal injury. Specificity for solid organ injury was 94% in the OC group and 57.1% in the no OC group. Sensitivity for solid organ injury was 84.2% in the OC group and 88.9% in the no OC group. The average time to abdominal CT scanning after placement of a nasogastric tube was 39.02 ± 18.73 minutes in the no OC group and 45.92 ± 24.17 minutes in the OC group (P=.008).Conclusion The addition of OC to the acute CT protocol for the evaluation of the patient with blunt abdominal trauma is unnecessary and delays time to CT scanning.
Article
To evaluate the diagnostic accuracy of CT in postoperative colorectal anastomotic leakage (AL). Two independent blinded radiologists reviewed 153 CTs performed for suspected AL within 60 days after surgery in 131 consecutive patients, with (n = 58) or without (n = 95) retrograde contrast enema (RCE). Results were compared to original interpretations. The reference standard was reoperation or consensus (a radiologist and a surgeon) regarding clinical, laboratory, radiological, and follow-up data after medical treatment. AL was confirmed in 34/131 patients. For the two reviewers and original interpretation, sensitivity of CT was 82 %, 87 %, and 71 %, respectively; specificity was 84 %, 84 %, and 92 %. RCE significantly increased the positive predictive value (from 40 % to 88 %, P = 0.0009; 41 % to 92 %, P = 0.0016; and 40 % to 100 %, P = 0.0006). Contrast extravasation was the most sensitive (reviewers, 83 % and 83 %) and specific (97 % and 97 %) sign and was significantly associated with AL by univariate analysis (P < 0.0001 and P < 0.0001). By multivariate analysis with recursive partitioning, CT with RCE was accurate to confirm or rule out AL with contrast extravasation. CT with RCE is accurate for diagnosing postoperative colorectal AL. Contrast extravasation is the most reliable sign. RCE should be performed during CT for suspected AL. • CT accurately diagnosed clinically suspected colorectal AL and showed good interobserver agreement • Contrast extravasation was the most sensitive and specific CT sign • Retrograde contrast enema during CT improved positive predictive value • Retrograde contrast enema decreased false-negative or indeterminate original CT interpretations.
Article
Purpose: Evaluation of diagnostic accuracy of abdominal CT depending on the type of enteric contrast agent. Methods and materials: Multislice CTs of 2,008 patients with different types of oral preparation (positive with barium, n = 576; neutral with water, n = 716; and no enteric contrast, n = 716) were retrospectively evaluated by two radiologists including delineation of intestinal segments and influence on diagnosis and diagnostic reliability exerted by the enteric contrast, using a three-point scale. Furthermore, diagnostic reliability of the delineation of selected enteric pathologies was noted. CT data were assigned into groups: oncology, inflammation, vascular, pathology, trauma and gastrointestinal pathology. Results: Delineation of the bowel was clearly practicable across all segments irrespective of the type of enteric contrast, though a slight impairment was observed without enteric contrast. Although delineation of intestinal pathologies was mostly classified "clearly delimitable" more difficulties occurred without oral contrast (neutral/positive/no contrast, 0.8 %/3.8 %/6.5 %). Compared to examinations without enteric contrast, there was a significant improvement in diagnosis that was even increased regarding the reader's diagnostic reliability. Positive opacification impaired detection of mucosal enhancement or intestinal bleeding. Conclusion: Water can replace positive enteric contrast agents in abdominal CTs. However, selected clinical questions require individual enteric contrast preparations. Pathology detection is noticeably impaired without any enteric contrast.
Article
OBJECTIVE. Our objective was to evaluate the impact of unenhanced CT on clinician diagnostic confidence and therapeutic efficacy in emergency department patients with clinically suspected renal colic. SUBJECTS AND METHODS. Questionnaires were completed on 93 patients who were referred to the radiology department with clinically suspected renal colic. We prospectively surveyed the clinician's diagnostic confidence and treatment plan before and after unenhanced abdominal and pelvic CT. RESULTS. Fifty-six patients (60%) had positive findings for calculi, 20 patients (22%) had normal findings, and alternative diagnoses were found in 17 patients (18%). The clinician's diagnostic certainty of stones before CT was variable with the largest frequencies at 41-60% (n = 30) and 71-90% (n = 35). The diagnostic certainty of stones after CT showed movement toward either less than or equal to 10% (n = 25) or greater than or equal to 91% (n = 51). The mean change in diagnostic confidence was 34%. Fifty-seven patients (61%) had a change in treatment plan. Specifically, the need for urology consultation as the initial treatment plan was reduced from 24 patients to one patient. Plans for admissions suggested before CT (n = 11) were nearly cut in half (n = 6) after imaging. Lastly, seven patients who would have initially been discharged were admitted to the hospital after imaging. CONCLUSION. CT significantly increased emergency department clinician diagnostic confidence and altered initial treatment decisions in patients with suspected renal colic. Most often, CT confirmed a ureteral stone and allowed appropriate discharge or urologic intervention. In a smaller subset of patients, CT established a significant alternative diagnosis that allowed the prompt initiation of appropriate treatment.
Article
The oral administration of a dilute positive iodinated contrast agent such as 2% Gastrografin is usually necessary to achieve optimal delineation of abdominal and pelvic organs. The amount of contrast agent administered and the timing of its administration depends on the site of suspected disease within the body. The simultaneous administration of antiperistaltic agents intravenously is generally unnecessary when utilizing the modern fast CT scanners. However, contrast agent-induced artifact may at times be troublesome, and we therefore suggest that lesions in the left lobe of the liver be scanned without positive contrast in the stomach. Negative contrast may also be useful in delineating disease: gas (carbon dioxide) has been shown to be useful in evaluating bladder tumors. We have also used air insufflation to facilitate the evaluation of small rectal tumors. Intravenous administration of contrast agent aids characterization of various disease entities and also facilitates the recognition of vascular structures (such as veins and arteries in the peripancreatic region). In our opinion both the infusion and bolus modes of contrast material administration have their place in the evaluation of abdominal and pelvic lesions by computed tomography. Newer techniques such as dynamic CT scanning will probably prove to be valuable both in delineating and characterizing disease.
Article
Study objective: To determine how frequently oral contrast medium (OC) is essential for computed tomography (CT) diagnosis of blunt intraabdominal injury and to quantify the delay associated with OC administration and the incidence of adverse effects. Methods: This retrospective chart review, with prospective reevaluation of CT scans for diagnostic value of OC, took place in a university teaching hospital and Level l trauma center. Participants were blunt-trauma victims admitted between June 1, 1988, and November 1, 1993, who had abdominal CT as part of their initial evaluation. Trauma registry records were used to identify study patients. Available charts and CTs were reviewed for all patients with intestinal/mesenteric and pancreatic injuries. Randomly selected cases of liver injury, spleen injury, and no intraabdominal injury were also reviewed. Blinded CT scans were reevaluated for quality of bowel opacification and value of OC to diagnostic impression. Results: During the study period, 2,162 blunt-trauma patients had an abdominal CT; 297 intraabdominal injuries were diagnosed in 248 patients. Full review was done on 124 charts, and 70 CT scans were reevaluated. Thirty-one (100%) of 31 liver and spleen injuries were diagnosed on CT, and OC was considered essential in none of these studies. One (4.5%) of 22 intestinal and mesenteric injuries was seen on CT, but this was the only such injury treated nonoperatively. None of 21 surgically confirmed intestinal/mesenteric injuries was seen on CT. Free air or free OC was seen in none of 7 cases of intestinal perforation. OC was judged essential in none of 20 scans in patients without intraabdominal injury. On 2 scans. OC was considered essential for the radiographic diagnosis. One of these was a normal pancreas at exploration (radiographic false-positive result). The only pancreatic injury requiring specific surgical treatment was missed on CT. Twenty-one percent of patients required placement of nasogastric tube for contrast administration after failing oral administration, and 23% vomited OC. One of 124 had documented aspiration of OC. Average additional time incurred in the ED for administration of OC was 144 minutes. Conclusion: OC is rarely essential for CT diagnosis of intraabdominal injury. It may improve sensitivity for pancreatic injury, but it does not help identify injuries requiring surgical treatment. Even with OC, CT is insensitive for intestinal injury. Vomiting and aspiration are significant risks. Use of OC adds a significant amount of time to ED evaluation. Adverse effects of OC administration, in this setting, may outweigh its benefits.
Article
To assess the effect of positive enteric contrast administration on automatic exposure control (AEC) CT radiation exposure in (1) a CT phantom, and (2) a retrospective review of patients. We scanned a CT phantom containing simulated bowel that was sequentially filled with water and positive enteric contrast, and recorded the mean volume CT dose index (CTDIvol). We also identified 17 patients who had undergone 2 technically comparable CT scans of the abdomen and pelvis, one with positive enteric contrast and the other with oral water. Paired Student's t-tests were used to compare the mean CTDIvol between scans performed with and without positive enteric contrast. Both the phantom and patient CT scans were performed using AEC with a fixed noise index. The mean CTDIvol for the phantom with simulated bowel containing water and positive enteric contrast were 8.2 ± 0.2 mGy, and 8.7 ± 0.1 mGy (6.1% higher than water, p=0.02), respectively. The mean CTDIvol for patients scanned with oral water and with positive enteric contrast were 11.8 mGy and 13.1 mGy, respectively (p=0.003). This corresponded to a mean CTDIvol which was 11.0% higher (range: 0.0-20.7% higher) in scans with positive enteric contrast than those with oral water in patients. When automatic exposure control is utilized for abdominopelvic CT, the radiation exposure, as measured by CTDIvol, is higher for scans performed with positive enteric contrast than those with oral water.