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ABSTRACT: This paper presents a new method for detecting the impact location in a buried gas duct. Gas leakage is often caused by the
mechanical impact forces of construction equipment. In order to prevent gas leakage due to an impact force, it is necessary
to detect the impact location at an early stage. For the detection of the impact location in a pipeline system, the correlation
method has been used as the conventional method. For the application of the correlation method, the diameter of a duct should
be small so that the acoustic wave inside the duct can propagate with non-dispersive characteristics, in the form of, for
example, a plane wave. However, when the diameter of the duct is large, the acoustic waves inside the duct propagate with
dispersive characteristics owing to the reflection of the acoustic wave off of the wall of the duct. This dispersive characteristic
is related to the acoustic modes inside a duct. Therefore, the correlation method does not work correctly for the detection
of the impact location. This paper proposes new methods of accurately measuring the arrival time delay between two sensors
attached to duct line system. This method is based on the time-frequency analyses of the short time Fourier transform (STFT)
and continuous wavelet transform (CWT). These methods can discriminate direct waves (non-dispersive waves) and reflective
waves (dispersive waves) from the measured wave signals through the time-frequency analysis. The direct wave or the reflective
wave is used to estimate the arrival time delay. This delay is used for the identification of the impact location. This systematic
method can predict the impact location due to the impact forces of construction equipment with more accuracy than the correlation
method.
KeywordsTime-frequency–Impact location–Cut-off frequency–Gas duct–Acoustic mode
Experimental Mechanics 05/2012; 51(6):947-958. · 1.52 Impact Factor
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ABSTRACT: To determine the efficacy of percutaneous transcatheter embolization in the management of patients with spermatic varicocoeles persisting or recurring after surgery.
Over a period of 10 years, 28 patients (age range 13-55 years) were referred for percutaneous transcatheter embolization of postsurgical, recurrent varicocoeles. Medical documents were retrospectively reviewed to evaluate past surgical history, subjective symptoms, and results of scrotal examination, ultrasound, and semen parameters. Pre-embolization venograms were analysed to assess the anatomy of the testicular vein. The technical and clinical outcomes of embolization were then determined.
The 28 patients included in the study had undergone laparoscopic varicocoelectomy (39.3%), high retroperitoneal ligation (25%), or inguinal ligation (25%). Subjective symptoms were scrotal pain (60.7%) and a palpable scrotal mass (50%) exclusively on the left side. Venograms revealed abnormalities of the left testicular vein in all cases. Embolization was technically successful in all but two cases, thus yielding an occlusion rate of 93%; a single case of suspected thrombophlebitis was the only complication. After excluding two, technically unsuccessful cases and one patient who was lost to follow-up, 25 patients underwent scrotal examination after embolization, which revealed complete resolution in 20 cases (80%), partial improvement in four cases (16%), and no improvement in a single case (4%). Among the follow-up group of patients, of the 12 who initially presented with scrotal pain, six (50%) were symptom-free and four (33.3%) had partial improvement.
Percutaneous transcatheter embolization of the testicular vein is technically feasible and effective for managing postsurgical recurrent varicocoeles.
Clinical radiology 12/2011; 67(4):359-65. · 1.65 Impact Factor
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ABSTRACT: Cytomegalovirus (CMV) can reactivate causing serious clinical problems during immunosuppression. CMV-specific CD8(+) T cells play an important role in the control of CMV reactivation. Using pentameric major histocompatibility complex (MHC) peptide complexes, we investigated cellular immune responses to CMV among healthy individuals and kidney transplantation recipients in Korea, which is an endemic area of CMV infection.
Analysis of CMV-specific T cells was performed on 28 healthy individuals and 40 recipients who bore human leukocyte antigen (HLA)-A2 or -A24. CMV pp65 pentamer-binding cells incubated with various monoclonal antibodies were measured by four-color flow cytometry.
Detectable levels of pentamer(+) CD8(+) T cells were present in 109/139 samples (78.4%) that stained with the A*02NLV-pentamer, while 15/67 samples (22.4%) stained with the A*24QYD-pentamer (P < .01). Among patients with HLA-A2, 22/24 (91.7%) samples showing positive CMV antigenemia revealed detectable pentamer(+) CD8(+) T cells, while 87/115 (75.7%) displaying negative CMV antigenemia had detectable pentamer(+) CD8(+) T cells (P = .04). There was no significant difference in percentages of pentamer(+) CD8(+) T cells between patients who did versus who did not experience episodes of CMV infection. The subpopulation of CMV-specific CD8(+) T cells in transplantation recipients was evaluated using phenotypic markers; memory cells comprised the majority of the CMV-specific CD8(+) T-cell population.
The A*02NLV-pentamer complex was useful to monitor CMV-specific T cells. However, MHC pentamer-based techniques did not provide a clear distinction between patients who are or are not at risk for CMV infection.
Transplantation Proceedings 09/2011; 43(7):2636-40. · 1.00 Impact Factor
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J M Kim,
S-K Lee,
S J Kim,
J-W Joh,
C H D Kwon,
Y H Choe,
M Shin, E Y Kim,
J I Moon,
G O Jung,
G-S Choi
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ABSTRACT: Epstein-Barr virus (EBV) infections, associated with posttransplant lymphoproliferative disorder (PTLD) are known to develop in cytomegalovirus (CMV)-infected transplant recipients due to the indirect effects of CMV. This study evaluated risk factors for PTLD among pediatric liver transplant recipients with CMV infections. We reviewed the medical records of 119 patients<or=18 years old who underwent liver transplantation between September 1996 and April 2009. Sixty-six subjects (55.5%) displayed CMV antigenemia during the study period; 15 (12.6%) developed PTLD. Of these, 10 developed PTLD after CMV antigenemia. The other patients (n=5) were excluded due to negative CMV antigenemia. The incidence of PTLD influenced by CMV infection was not significantly different from the incidence of PTLD without underlying CMV (P=.258). There were no differences in age, gender, antiviral prophylaxis, type of liver transplantation, or acute rejection episodes in the incidence of between patients with versus without PTLD. EBV but not CMV high-risk groups were a predictor for the development of PTLD (P=.035). CMV syndrome, tissue-invasive CMV disease, and CMV peak titer were not associated with an increased risk of PTLD. The primary risk factor for PTLD was EBV high-risk patients (donor positive/recipient negative). CMV disease was not associated with PTLD in pediatric liver transplant recipients with CMV infections.
Transplantation Proceedings 04/2010; 42(3):895-9. · 1.00 Impact Factor
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ABSTRACT: There is some controversy regarding the exact cytomegalovirus (CMV) antigenemia titer that should be used as a guideline for preemptive anti-CMV therapy. We performed 634 consecutive kidney transplantations between January 2000 and June 2007. Preemptive therapy employed intravenous gancyclovir treatment when the CMV antigenemia titer was >or=50/4x10(5) leukocytes after kidney transplantation. The 634 recipients were allocated into 2 groups according to the peak CMV antegenemia: group A, CMV antigenemia titer<50/4x10(5) (n=550); and group B, >or=50/40x10(5) (n=84). Among the 634 recipients, 264 were positive for CMV antigenemia, and 61 developed symptomatic CMV infections. The incidence of symptomatic CMV infections in group B was significantly higher than in group A. Two cases in both groups developed tissue-proven CMV disease: group A CMV colitis and CMV nephritis, and group B, 2 cases of CMV colitis. Graft and patient survival rates in groups A and B at 5 years posttransplantation were not different. The authors concluded that a CMV antigenemia titer of >or=50/4x10(5) leukocytes can be considered an appropriate guideline for preemptive anti-CMV therapy.
Transplantation Proceedings 04/2010; 42(3):804-10. · 1.00 Impact Factor
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ABSTRACT: Portal vein complications (PVC) after pediatric living donor liver transplantation (LDLT) have rarely been reported. We evaluated the long-term incidence and of the risk factors for PVC after pediatric LDLT.
From April 1997 to November 2008, 96 pediatric patients underwent LDLT using left lateral segments or left lobes. We investigated recipient factors, donor factors, and operative factors through medical records. The portal vein sizes in 96 recipients ranged from 2.7 mm to 13.0 mm (median=5.0 mm). Portal vein reconstruction was usually performed with the graft portal vein anastomosed to the bifurcation of the recipient right and left portal veins, the so-called "branch patch".
PVC occurred in 11 patients (11.5%) including early PVC (n=3), late PVC (n=8). The disease-free survivals at 1, 5, and 10 years after LDLT were 94.7%, 88.7%, and 86.0%. Upon univariate analysis, a portal vein size<5 mm graft-to-recipient weight ratio (GRWR)>or=4%, transfusion volume>or=270 mL were significant risk factors for PVC. Body weight<8 kg and previous operative history tendes to be adverse for PVC. Upon multivariate analysis by Cox regression, portal vein size<5 mm was a highly significant factor for PVC after pediatric LDLT (hazard ratio=5.627, P=.027).
The disease-free survival at 10 years after LDLT was 86.0%. If the recipient's portal vein size<5 mm received a large-for-size graft (GRWR>or=4%), it is important to observe by regular Doppler ultrasonography follow-up to detect PVC.
Transplantation Proceedings 04/2010; 42(3):871-5. · 1.00 Impact Factor
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ABSTRACT: Patients with unresectable, beyond Milan criteria, hepatocellular carcinoma (HCC) invariably undergo palliative transarterial chemoembolization (TACE). The aim of this study was to compare the outcomes of conventional TACE versus liver transplantation (LT) in unresectable (beyond Milan criteria) HCC. Twelve patients underwent LT and 86 TACE for unresectable, beyond Milan criteria HCC. The inclusion criteria were a single tumor<or=6.5 cm or <or=5 tumors and all tumors<or=5 cm based on initial radiologic findings. We excluded patients with double primary cancers, age>60 years, vascular invasion, or extrahepatic spread. Survival rates were calculated using the Kaplan-Meier method. Multivariate analysis showed that TACE was a prognostic factor for survival (hazard ratio, 16.66, P=.000). The LT group showed significantly better survival than the TACE cohort. Two cases (16.7%) in the LT group recurred at a median time of 13.5 months. Survival rates at 1, 3, and 5 years were 100%, 88.9%, and 76.2% in the LT group, and 85.6%, 45.6%, and 21.4% in the TACE group, respectively. Patients with unresectable, beyond Milan criteria HCC should be given the option to receive LDLT, because LT offers a significantly better likelihood of survival than TACE.
Transplantation Proceedings 04/2010; 42(3):821-4. · 1.00 Impact Factor
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G O Jung,
M R Yoon,
S-J Kim,
M J Sin, E Y Kim,
J I Moon,
J M Kim,
G-S Choi,
C H D Kwon,
J-W Cho,
S K Lee
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ABSTRACT: The aim of this study was to analyze risk factors for delayed graft function (DGF) after deceased donor kidney transplantation and to compare the clinical outcomes of non-DGF versus DGF recipients.
From January 2004 to June 2008, 75/154 kidneys were transplanted into 74 recipients. We classified the recipients into two groups: group 1 (n=61) without DGF and group 2 (n=13) with DGF.
On univariate analysis, recipient age (P=.048) cause of brain death (traumatic brain injury vs disease, P=.016), blood urea nitrogen (P=.002), serum creatinine (P=.001), arterial pH (P=.019), and serum sodium level (P=.012) just before organ procurement showed significant differences. On multivariate analysis, the cause of brain death (P=.015, hazard ratio [HR]: 7.086), the terminal serum creatinine>or=1.5 mg/dL before organ procurement (P=.007, HR: 10.132), and recipient age over >or=50 years (P=.021, HR: 7.767) were independent risk factors for the development of DGF. Graft failures occurred among 5/74 recipients with 5-year graft survivals between group 1 and group 2 of 91.7% and 84.6%, respectively. Patient death occurred in five cases, most by due to infection. The 5-year patient survival between groups 1 and 2 were 93.9% and 84.6%, respectively (P = .106).
The independent risk factors for DGF were the cause of brain death, the terminal creatinine level, and the recipient age. In deceased donor kidney transplantation, DGF may have less effect on long-term patient and graft survivals.
Transplantation Proceedings 04/2010; 42(3):705-9. · 1.00 Impact Factor
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ABSTRACT: Cytomegalovirus (CMV) infection is not only a common complication after liver transplantation but also a significant contributing factor to morbidity and mortality. We investigated whether preemptive therapy can prevent CMV syndrome or tissue-invasive CMV disease in an endemic area. Preemptive therapy was initiated when more than 10 positive CMV pp65 antigen-positive cells per 400,000 white blood cells were detected, regardless of clinical manifestations. Intravenous ganciclovir as preemptive therapy was administered daily for 10 to 14 days until negative results were achieved. The incidence of initial CMV antigenemia and CMV syndrome during the posttransplantation period was 49.7% (353/710) and 5.2% (37/710), respectively. One hundred eight-two patients (51.6%) received ganciclovir as preemptive therapy. Patients with CMV antigenemia who received preemptive therapy had high Model for End-Stage Liver Disease score, repeat operation, renal dysfunction, infection, low hemoglobin concentration, low platelet count, low albumin concentration, high international normalized ratio, high total bilirubin value, high aspartate transaminase concentration, and high CMV peak titer. Cytomegalovirus syndrome and tissue-invasive CMV disease were more common in these patients. The survival curve in patients without CMV syndrome was better than that in those with CMV syndrome (P=.000). Patients with more than 10 pp65 antigen-positive cells per 400,000 white blood cells should be treated aggressively with an antiviral agent as preemptive therapy because CMV infection is common in CMV-endemic areas and patients with CMV syndrome demonstrate poor survival rates.
Transplantation Proceedings 04/2010; 42(3):825-9. · 1.00 Impact Factor
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ABSTRACT: The delayed onset of cytomegalovirus (CMV) infection after liver transplantation can place patients at risk for graft failure and mortality.
We compared early versus delayed onset of CMV infection to identify risk factors for mortality among liver transplant recipients in an endemic area.
Among 710 consecutive adult liver transplant recipients, incidence of CMV infection was 47.5% (337/710). Male gender, biliary complications, acute rejection episodes, antilymphocyte antibodies high hemoglobin, and high total bilirubin were significantly different among patients with delayed versus early onset CMV infections. The overall incidence of early versus delayed CMV infections was 43.1% (306/710) versus 4.4% (31/710). Among them, 11.1% (34/306) and 25.8% (8/31) of patients developed CMV disease.
These results showed that a higher proportion of patients developed disease among delayed CMV infected patients (P=.039). The overall and graft survival curves for patients with early onset CMV infections were better than those of patients who had delayed onset CMV infections (P=.026 and P=.014). Recurrence of hepatitis B virus, hepatic dysfunction, and retransplantation were associated with increased mortality among patients who had a delayed CMV infection.
Transplantation Proceedings 04/2010; 42(3):884-9. · 1.00 Impact Factor
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ABSTRACT: Sinonasal organized hematoma (OH) is an uncommon, nonneoplastic benign condition that can be locally aggressive. The purpose of this work was to characterize the CT and MR imaging findings of sinonasal OH.
CT (n = 11) and MR (n = 10) images of 12 patients (9 men and 3 women; mean age, 41 years; range, 12-76 years) with pathologically proved sinonasal OH were retrospectively reviewed. Particular attention was put on the location, shape, size, extent, internal architecture, and enhancement pattern of the lesion and associated sinus wall change.
The lesions were seen as an expansile (n = 9) or nonexpansile (n = 3) mass, ranging in size from 2.2 to 6.0 cm (mean, 4.2 cm), primarily involving the maxillary sinus (n = 11) or nasal cavity (n = 1) unilaterally. The ipsilateral nasal cavity was also involved in 9 of 11 maxillary sinus lesions. Smooth sinus wall erosion other than the medial maxillary sinus wall was noted in 8 lesions. The internal architecture was best displayed on T2-weighted MR images on which all of the lesions were seen as a mixture of marked heterogeneous hypointensity and isointensity, surrounded by a hypointense peripheral rim, reflecting histologic heterogeneity of the lesion composed of hemorrhage, fibrosis, and neovascularization. Marked irregular nodular, papillary, or frondlike enhancement at the areas of neovascularization was also a typical finding seen in all of the lesions.
An expansile soft tissue mass, smooth sinus wall erosion, marked heterogeneous signal intensity with a hypointense peripheral rim on T2-weighted MR images, and marked irregular nodular, papillary, or frondlike enhancement are characteristic CT and MR imaging findings of sinonasal OH.
American Journal of Neuroradiology 07/2008; 29(6):1204-8. · 2.93 Impact Factor
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J H Shin,
S K Lee,
H-Yo Song,
J-S Kim,
H Choe,
E-H Kim,
I J Lee,
T-H Kim, E-Y Kim,
C-W Woo,
K Hoon Nah
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ABSTRACT: The objective of the study was to evaluate the efficacy of beta-radiation using a rhenium-188-mercaptoacetyltriglycine ((188)Re-MAG(3))-filled balloon for preventing tissue hyperplasia secondary to bare stent placement in a rabbit oesophageal model. Immediately following bare stent placement in 30 rabbits, 10 underwent conventional contrast-filled balloon dilation (control group, Group I), and 20 underwent (188)Re-MAG(3)-filled balloon dilation, with half of these receiving 20 Gy (Group II) and half receiving 40 Gy (Group III) at a 1 mm tissue depth. Diameter percentage stenosis was calculated using oesophagography performed before sacrifice 6 weeks later. Gross and microscopic findings were obtained at both an area of untreated oesophageal tissue and a mid-stent area. Apoptosis and an apoptotic index in the mid-stent area were evaluated in two rabbits from each group. 13 rabbits survived the scheduled 6-week stent placement. Diameter percentage stenosis for Groups II and III was significantly lower than for Group I. The oesophageal mucosa showed nodularity in Group I and smoothness in Groups II and III. Oesophageal mucosal erythema (n = 9) and perforations (n = 10) were observed in Groups II and III only. Mid-stent epithelial layer thickness and muscularis propria destruction differed between the three groups (p<0.05). Apoptosis was increased and the apoptotic index was higher in Groups II and III than in Group I. In conclusion, (188)Re-MAG(3)-filled balloon dilation was effective in preventing tissue hyperplasia secondary to bare stent placement, but at the cost of an increased risk of radiation-induced mucosal inflammation and perforation, in a rabbit oesophageal model. Apoptosis may be the mechanism underlying this irradiation-induced suppression of tissue hyperplasia.
The British journal of radiology 06/2008; 81(965):413-21. · 2.11 Impact Factor
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ABSTRACT: Cornelia de Lange syndrome is a rare developmental malformation syndrome with a high prevalence of hearing impairment. The purposes of this study were to describe the characteristic temporal bone CT findings in patients with Cornelia de Lange syndrome and to correlate audiometric data with radiologic findings in these patients. Materials and
Ten children (6 girls and 4 boys; mean age, 42.0 months) who were clinically diagnosed with Cornelia de Lange syndrome (classic, n = 5; mild form, n = 5) were enrolled. Temporal bone CT was prospectively performed, and 32 aspects of each temporal bone CT were analyzed, 21 by direct measurement and 11 by visual inspection. Twenty age-matched children (n = 20 ears) with normal temporal bone CT scans served as a control group. Audiologic tests were also performed on all patients.
Characteristic temporal bone CT findings of Cornelia de Lange syndrome were external auditory canal stenosis, soft-tissue opacification of the hypoplastic tympanomastoid cavity, dysmorphic ossicle, hypoplastic cochlea, and dysplastic vestibule, all of which were more prevalent in patients with the classic form of the disease than in those with the mild form. Children who had more severe structural abnormalities on temporal bone CT had worse hearing levels compared with those without structural abnormalities.
Temporal bone CT scans in Cornelia de Lange syndrome could document combined structural abnormalities of the external, middle, and inner ear, which were one of the characteristic clinical manifestations; CT abnormalities were well correlated with the audiometric data.
American Journal of Neuroradiology 04/2008; 29(3):569-73. · 2.93 Impact Factor
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ABSTRACT: Although the hyperattenuated middle cerebral artery sign is known to be related to acute infarction, the volume of clot associated with it is not known. We investigated whether the presence or absence of hyperattenuated artery sign (HAS) on noncontrast CT (NCCT) can predict the thrombus volume.
We enrolled 90 consecutive patients with acute infarction who underwent both 5- and 1.25-mm NCCT and CT angiography (CTA). HAS was determined on 5-mm NCCT retrospectively. According to the location of thrombi, the patients were classified into ICA (ICA terminus/ICA and others), M1 (M1/both M1 and M2), and M2 (M2) groups. Thrombus volumes were measured by 1.25-mm NCCT and were compared between patients with and without HAS.
Occlusion of major arteries was seen on CTA in 78 patients. HAS was found in 46 patients (59.0%). The mean thrombus volume was significantly larger in patients with HAS than in those without except for the M2 group (ICA group: [n = 14], 188.7 +/- 122.5 mm(3) versus 39.4 +/- 12.1 mm(3) [P = .022]; M1 group: [n = 42], 128.1 +/- 119.2 versus 56.8 +/- 32.5 [P = .005]; M2 group: [n = 22], 34.7 +/- 32.2 versus 20.0 +/- 20.0 [P = .18]). Thrombus volumes determined by receiver operating characteristic curve analysis were 52.36 mm(3) in the ICA group (sensitivity, 90.9%; specificity, 100%) and 53.96 mm(3) in the M1 group (sensitivity, 88.0%; specificity, 58.8%).
Thrombus volumes were significantly larger in patients with HAS than in those without in ICA and M1 occlusions. The detection of HAS may provide an idea concerning rapid and dichotomized estimation of thrombus volume, which may be helpful for treatment decisions in potential candidates for thrombolysis.
American Journal of Neuroradiology 03/2008; 29(2):359-62. · 2.93 Impact Factor
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ABSTRACT: MR imaging features of metronidazole-induced encephalopathy (MIE) have not been fully established. This study was undertaken to determine the topographic distributions and diffusion-weighted imaging (DWI) findings of MIE.
We retrospectively evaluated the initial MR images (n = 7), including DWI (n = 5), and follow-up MR images (n = 4) after drug discontinuation in 7 patents with clinically diagnosed MIE. The topographic distributions of lesions were evaluated on MR images, and DWI signal intensities and apparent diffusion coefficient (ADC) values of the lesions were assessed.
MR images demonstrated bilateral symmetric T2 hyperintense lesions in the cerebellar dentate nucleus (n = 7), midbrain (n = 7), dorsal pons (n = 6), medulla (n = 4), corpus callosum (n = 4), and cerebral white matter (n = 1). Brain stem lesions involved the following: tectum (n = 5), tegmentum (n = 4), red nucleus (n = 3) of the midbrain, vestibular nucleus (n = 6), and a focal tegmental lesion involving the superior olivary nucleus (n = 6) and abducens nucleus (n = 4) of the pons and vestibular nucleus (n = 4) and inferior olivary nucleus (n = 1) of the medulla. DWI (n = 5) showed isointensity or hyperintensity of lesions, and the decreased ADC value was found only in the corpus callosum lesions (n = 2). All detected lesions were completely reversible at follow-up except for the single corpus callosum lesion with an initial low ADC value.
Brain lesions were typically located at the cerebellar dentate nucleus, midbrain, dorsal pons, medulla, and splenium of the corpus callosum. According to DWI, most of the lesions in MIE probably corresponded to areas of vasogenic edema, whereas only some of them, located in the corpus callosum, corresponded to cytotoxic edema.
American Journal of Neuroradiology 11/2007; 28(9):1652-8. · 2.93 Impact Factor
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ABSTRACT: Rhabdoid meningioma (RM) is a recently described variant of malignant meningioma, with radiologic features currently not well characterized in the medical literature. The purpose of this study was to describe and characterize clinical features and imaging findings associated with RM.
CT (n = 8) and MR (n = 15) images of 15 patients (4 men and 11 women; mean age, 52 years; range, 22-75 years) with 16 pathologically proved RMs along with associated clinical records were retrospectively reviewed. All of the patients underwent surgical resection and had additional radiation therapy except for 1 patient. After surgery, the patients had follow-up brain MR imaging to evaluate for tumor recurrence.
Nine lesions (56%) were located in the cerebral convexity, and 4 lesions (25%) were located in the parasagittal areas. The tumors were isointense (n = 15) to gray matter on T1-weighted images, whereas they were hyperintense (n = 14) on T2-weighted images. On gadolinium-enhanced T1-weighted images, homogeneous enhancement was seen in 10 lesions, and heterogeneous enhancement was seen in 6 lesions that had cysts. Cystic components were noted in 6 lesions (38%). Severe peritumoral edema was seen in 12 lesions (75%). Nine lesions (56%) had hyperostosis, and 5 of them also had bone destruction. Among the 8 cases with initial CT scans, only 1 had amorphous calcifications (13%). There was only 1 recurrence of RM found during the follow-up period after surgical resection.
RMs tend to have prominent peritumoral edema, cystic components, and bone involvement.
American Journal of Neuroradiology 10/2007; 28(8):1462-5. · 2.93 Impact Factor
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ABSTRACT: Intracranial solitary fibrous tumors (ISFTs) are rare mesenchymal neoplasms originating in the meninges. The aim of this study was to describe the CT, MR imaging, and angiographic features of the solitary fibrous tumor and to identify imaging characteristics.
We retrospectively reviewed CT, MR, and angiographic findings in 6 cases of ISFT. We evaluated the size, shape, and location of the tumor; the internal content and margin of the lesion; the pattern of enhancement; and the change of the adjacent structures. Density on noncontrast CT scans, signal intensity on MR images, and angiographic features were also documented.
Each lesion appeared as a discrete extra-axial mass (size, 3-7 cm; mean, 5 cm). Five lesions were entirely solid, and 1 had peritumoral cyst. All 5 of the noncontrast CT scans showed hyperattenuated masses, and the tumors exhibited marked heterogeneous enhancement. No lesion contained calcification, and 2 cases showed bone invasions. On the MR images, 4 lesions showed mixed signal intensity on T2-weighted imaging. All of the lesions revealed marked heterogeneous enhancement. All of the tumors had thickening of the meninges adjacent to the tumor. Angiography showed delayed tumor blushing in all, and 3 of them had dysplastic dilation of the tumor vessels.
Although there are no pathognomonic imaging findings, some imaging features, such as the "black-and-white mixed" pattern on T2-weighted images and marked heterogeneous enhancement, might be helpful in the diagnosis of intracranial solitary fibrous tumor.
American Journal of Neuroradiology 10/2007; 28(8):1466-9. · 2.93 Impact Factor
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Clinical Radiology 05/2007; 62(5):491-4. · 1.95 Impact Factor
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ABSTRACT: Thin-section noncontrast CT (NCT) can detect thrombi in large arteries and can provide a measure of thrombus composition based on Hounsfield Units (HU). A study using polyethylene tubes as a model of intracranial arteries concluded that the HUs of platelet-rich thrombi are lower than those of erythrocyte-rich thrombi. Thrombus HUs were measured by NCT in 34 patients with acute ischemic stroke before thrombolysis. Thrombi with lower HU counts were resistant to thrombolytics.
Neurology 12/2006; 67(10):1846-8. · 8.31 Impact Factor
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ABSTRACT: We sought to determine whether an early CT ischemic lesion showing parenchymal hypoattenuation might be undetectable on diffusion-weighted imaging (DWI) in acute cerebral ischemia.
We retrospectively evaluated CT and MR images of 70 consecutive patients with acute middle cerebral artery (MCA) infarction. All patients underwent CT and MR imaging within 6 hours of symptom onset. We determined the presence of reversed discrepancy (RD), defined as an early ischemic lesion showing parenchymal hypoattenuation on CT but no hyperintensity on DWI. CT Hounsfield units (HU), apparent diffusion coefficients (ADCs), and perfusion parameters were calculated for RD lesions.
RD was found in 9 (12.9%) patients and at basal ganglia (89%). The mean HU of RD lesion was lower than that of normal tissue (DeltaHU, 2.33 +/- 0.74, P < .001). RD lesions showed no significant decrease of ADC (ADC ratio, 0.97 +/- 0.07, P = .059) and cerebral blood flow (relative CBF, 0.87 +/- 0.20, P > 0.05). Delayed DWI hyperintensity occurred in 8 (88.8%) RD lesions, and all lesions progressed to infarction. In 6 (66%) of 9 patients with RD, Alberto Stroke Program Early CT scores of ischemic lesions were lower on CT than those on DWI.
RD was uncommonly found mainly in basal ganglia, and all RD lesions progressed to infarction at follow-up. Early CT ischemic lesion showing parenchymal hypoattenuation may be undetectable on DWI, and DWI may underestimate extent of severe ischemic tissue in patients with acute MCA infarction.
American Journal of Neuroradiology 11/2006; 27(9):1990-5. · 2.93 Impact Factor
