[Show abstract][Hide abstract] ABSTRACT: Purpose: Detection and quantification of coronary artery
calcium (CAC) has a prognostic value for future cardiovascular events,
beyond that accrued from other cardiovascular risk factors. CAC is
conventionally measured as an Agatston score from an EKG-gated
non-contrast CT of the heart using special software. The predominant
indication for coronary CT angiography (CCTA) in clinical practice
is to evaluate obstructive coronary artery disease (CAD) in a low to
intermediate pretest probability population. At present there is no
commercially available software for CAC measurement on CCTA scans.
The purposes of this study were twofold. First, the study examines the
correlation of estimated CAC from CCTA, using a novel method of visual
scoring on the CCTA exam and comparing with the measured Agatston
score from a non-contrast CAC score scan. Second, the study evaluates
the performance of such estimation of CAC across radiologists with
varying degrees of experience.
Methods: Two cardiac radiologists and a chest radiologist, with
varying degrees of experience, evaluated 100 coronary CT angiograms
for visual scoring of CAC. The three major coronary vascular segments;
left anterior descending artery (LAD) including left main coronary
artery (LM), left circumflex coronary artery (LCX) and right coronary
artery (RCA) were examined and scored for linear extent (0-4) as well
as thickness (0-3). The linear and thickness scores for each segment was
multiplied to get a vessel score (0-12) and total CAC score was derived
by adding all the vessel scores (0-36). Statistical analysis was performed
using Kappa statistic and Spearman Rank Correlation for the agreement
with the Agatston scores from non contrast EKG gated calcium score
CT scans performed at the same time as the CCTA. The scores of the
senior cardiac radiologist with 30 years of experience were used for the
primary analysis and the readings from the other two radiologists were
used to calculate the inter-reader variability.
Results: Overall, 59 % and 57 % of patients had CAC detected by
Agatston score and visual score respectively. CAC by visual score on
CCTA strongly correlated with the Agatston score (Spearman correlation
coefficient 0.88, P < 0.001). In 7 cases visual scoring failed to detect
minimal CAC with low Agatston CAC score (mean 4.1, range 1-13).
Visual score of > 7 identified CAC > 100 with an area under the curve of
0.965, sensitivity of 0.88 and a specificity of 0.92. A visual score of > 12
identified CAC > 300 with an area under the curve of 0.970, sensitivity
of 0.95 and specificity of 0.90. The inter-reader agreement with the
other cardiac and chest radiologist was high, with Spearman correlation
coefficients of 0.90 & 0.91 (p < 0.001).
Conclusion: The visual estimation and stratification of CAC on CCTA
is feasible and correlates well with the Agatston score and shows good
inter-reader correlation. This additional information from CCTA will be
useful for cardiovascular risk stratification and management.
[Show abstract][Hide abstract] ABSTRACT: To determine whether the presence of bone bars (BB) identified on anteroposterior hip radiographs are more prevalent in patients that have had a hip fracture as compared to patients without a fracture.
Ninety-two Caucasian women with a unilateral proximal femur fracture were retrospectively evaluated and randomly selected using radiology database records to comprise the investigational group. Ninety-eight age-matched Caucasian women without hip fracture were selected as a control group. Anteroposterior hip radiographs were evaluated for the presence of BBs by two musculoskeletal radiologists. Chi-square tests were used to assess whether fractures were more prevalent in patients with BB than those without BB.
The patient population was comprised Caucasian women with a mean age of 79.8 ± 6.4 years in the control group and 79.9 ± 6.6 years in the investigational group. Regardless of the reader, BB were identified in a significantly higher percentage of women with a fracture (75 versus 39%, p < 0.001 or 53 versus 38%, p = 0.041) as compared to those without a fracture.
BB are associated with hip fracture. Their presence is a trigger for requesting a dual-energy x-ray absorptiometry (DXA) examination to confirm or refute a diagnosis of low bone mineral density (BMD) and a subsequent increased risk of fracture.
[Show abstract][Hide abstract] ABSTRACT: To measure reader variability related to the evaluation of screening chest radiographs (CXRs) for findings of primary lung cancer.
From the National Lung Screening Trial (NLST), 100 cases were randomly selected from baseline CXR examinations for retrospective interpretation by 9 NLST radiologists; images with noncalcified lung nodules (NCNs) or other abnormalities suspicious for lung cancer as determined by the original NLST reader were oversampled. Agreement on the presence of pulmonary nodules and abnormalities suspicious for cancer and recommendations for follow-up were assessed by the multirater κ statistic.
The multirater κ statistic for interreader agreement on the presence of at least 1 NCN was 0.38. Rates at which readers reported the presence of at least 1 NCN ranged from 32% to 63% (mean, 41%); among 16 subjects with NCN and a cancer diagnosis within 1 year of the CXR examination, an average of 87% (range, 81% to 94%) of cases were classified as suspicious for cancer across all readers. The multirater κ for agreement on follow-up recommendations was 0.34; pairwise κ values ranged from 0.15 to 0.64 (mean, 0.36). For all subjects, readers recommended a follow-up procedure classified as high level (computed tomography, fluorodeoxyglucose-positron emission tomography, or biopsy) 42% of the time on average (range, 30% to 67%); this increased to 84% (range, 52% to 100%) when readers reported an NCN and 88% (range, 82% to 94%) for subjects with cancer.
Reader agreement for screening CXR interpretation and follow-up recommendations is fair overall but is high for malignant lesions.
[Show abstract][Hide abstract] ABSTRACT: Our goal was to investigate the effect of displayed image magnification on perception of the size of hepatic lesions on abdominal computed tomography (CT) scans. Institutional review board approval and informed observer consent were obtained. Three experienced radiologists reviewed 90 CT image pairs in one session. Each image pair demonstrated a solitary, well-defined hypodense hepatic lesion measuring greater than 1 cm obtained at two points in time. The image pairs were presented three times in random order, once with the left image magnified, once with the right image magnified, and once with neither image magnified. The radiologists were asked to determine on which image the lesion was smaller or if there was no difference. The responses were analyzed statistically. The proportion of correct responses increased significantly as the difference in lesion size increased (p < 0.001). The percent of correct responses was higher when neither CT image was magnified. Magnification of one image decreased the accuracy of the readers' performance, especially at smaller differences, both of which were statistically significant (p < 0.001). Thus, accuracy of detecting lesion size differences was degraded when the images were presented at differing magnification. This should be kept in mind when evaluating serial CT scans for growth or regression of tumors and other lesions.
Journal of Digital Imaging 07/2011; 25(2):266-70. DOI:10.1007/s10278-011-9403-0 · 1.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The contribution of nitric oxide (NO) to the pathophysiology of asthma remains incompletely defined despite its established pro- and anti-inflammatory effects. Induction of the inducible nitric oxide synthase (iNOS), arginase, and superoxide pathways is correlated with increased airway hyperresponsiveness in asthmatic subjects. To determine the contributions of these pathways in proximal and distal airways, we compared bronchial wash (BW) to traditional bronchoalveolar lavage (BAL) for measurements of reactive nitrogen/oxygen species, arginase activation, and cytokine/chemokine levels in asthmatic and normal subjects. Levels of NO were preferentially elevated in the BAL, demonstrating higher level NOS activation in the distal airway compartment of asthmatic subjects. In contrast, DHE(+) cells, which have the potential to generate reactive oxygen species, were increased in both proximal and distal airway compartments of asthmatics compared to controls. Different patterns of cytokines and chemokines were observed, with a predominance of epithelial cell-associated mediators in the BW compared to macrophage/monocyte-derived mediators in the BAL of asthmatic subjects. Our study demonstrates differential production of reactive species and soluble mediators within the distal airways compared to the proximal airways in asthma. These results indicate that cellular mechanisms are activated in the distal airways of asthmatics and must be considered in the development of therapeutic strategies for this chronic inflammatory disorder.
Free Radical Biology and Medicine 03/2011; 50(11):1679-88. DOI:10.1016/j.freeradbiomed.2011.03.015 · 5.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Pediatric acute care nurses questioned the practice of weighing disposable infant diapers immediately after voiding. This study asked the research question, "Does volume of saline, diaper configuration, and/or size of diaper statistically effect changes in diaper weights over time?" The method was an experimental, laboratory model. Pre-set volumes of saline were added to disposable diapers that were then left folded or unfolded. Each diaper was weighed immediately post-wetting and re-weighed at hourly intervals for seven hours. Data were analyzed using a repeated measures analysis of variance (RMANOVA) with balanced data (F-test). Diaper weight changes over time were statistically significant for all time points and for all volumes regardless of diaper size; however, the changes in weight were small and without clinical significance. It is appropriate to weigh diapers at the end of eight hours without risk of altering subsequent fluid management of patients in open-air, non-humidified environments. This practice has led to more efficient use of nurses' time with fewer interruptions for patients and families.