Faculty Bibliography

OBJECTIVE: Dual-source CT improves temporal resolution, and theoretically improves the diagnostic image quality of coronary artery examinations without requiring preexamination beta-blockade. The purpose of our study was to show the improved diagnostic image quality of dual-source CT compared with single-source CT despite the absence of preexamination beta-blockade in the dual-source CT group. MATERIALS AND METHODS: We performed a retrospective analysis of consecutive patients who underwent coronary artery evaluation with either single-source CT or dual-source CT at our institution between February 2005 and October 2006. Examination reports were analyzed for the presence of image artifacts, and image quality was graded on a 3-point scale (no, mild, or severe artifact). Type of artifact (motion, calcium, quantum mottle) was also noted. RESULTS: Examinations (339 single-source CT and 126 dual-source CT) of 465 patients were analyzed. Artifact was reported in 39.8% of examinations using single-source CT and in 29.4% of examinations using dual-source CT (p < 0.05). The number of examinations with motion artifact was significantly higher with single-source CT than with dual-source CT (15.9% vs 4.8%; p < 0.001) despite significantly higher heart rates in the dual-source CT group (59.4 +/- 8.4 vs 68.6 +/- 14.6 beats per minute; p < 0.001). No patients in the dual-source CT group received preexamination beta-blockade compared with 81% of patients in the single-source CT group. The presence of severe (nondiagnostic) calcium artifact was also significantly reduced in the dual-source CT group (13.0% vs 3.2%; p < 0.001). CONCLUSION: Dual-source CT provides significantly better diagnostic image quality than single-source CT despite higher heart rates in the dual-source CT group. These findings support the use of dual-source CT for coronary artery imaging without the need for preexamination beta-blockade

PURPOSE: To retrospectively evaluate the sensitivity and specificity of several morphologic findings that may be seen with cystic pancreatic lesions, in the diagnosis of pseudocyst at magnetic resonance (MR) imaging. MATERIALS AND METHODS: This study was institutional review board approved and HIPAA compliant. From January 1, 2005, to December 31, 2007, electronic radiology and pathology databases were searched to identify patients with pancreatic cystic neoplasms or pseudocysts who underwent pancreatic MR imaging. Twenty-two patients with cystic pancreatic neoplasms that were confirmed at surgical resection (n = 12) or endoscopic ultrasonography (US) with cystic fluid analysis (n = 10) were identified. Of 20 patients with pancreatic pseudocysts, seven had pseudocysts that were identified at pathologic resection and 13 had a clinical history of pancreatitis, with initial computed tomography (CT) revealing no pancreatic cyst and subsequent follow-up MR imaging depicting cystic lesions. Two abdominal radiologists independently and randomly evaluated each case for presence or absence of septa and internal dependent debris and for external cyst morphology on axial and coronal T2-weighted images and three-dimensional gradient-echo T1-weighted images obtained before and after intravenous contrast agent administration. Logistic regression for correlated data was used to assess the usefulness of internal debris, external morphology, and septa for differentiating cystic neoplasms from pseudocysts. RESULTS: The readers' assessments of the presence or absence of cystic debris were concordant for 40 (95%) of the 42 patients, with a kappa coefficient of 0.889, which indicated nearly perfect agreement. Thirteen (93%) of 14 lesions found to have debris by either or both readers were pseudocysts, and only one (4%) of the 22 cystic neoplasms had debris. Both readers were more likely to identify septa within cystic neoplasms than within pseudocysts; however, the difference was not significant for either reader. The readers were more likely to observe microlobulated morphology in cystic neoplasms than in pseudocysts, with the difference between these lesion types, in terms of prevalence of microlobulated morphology, exhibiting a trend toward-but not reaching-statistical significance (P = .0627). CONCLUSION: Presence of internal dependent debris appears to be a highly specific MR finding for the diagnosis of pancreatic pseudocyst

PURPOSE: To compare the performance of apparent diffusion coefficient (ADC) measurement obtained with diffusion-weighted (DW) magnetic resonance (MR) imaging in the characterization of non-fat-containing T1 hyperintense renal lesions with that of contrast material-enhanced MR imaging, with histopathologic analysis and follow-up imaging as the reference standards. MATERIALS AND METHODS: Institutional review board approval was obtained for this HIPAA-compliant retrospective study, and the informed consent requirement was waived. Two independent observers retrospectively assessed MR images obtained in 41 patients with non-fat-containing T1 hyperintense renal lesions. The MR examination included acquisition of DW and contrast-enhanced T1-weighted images. For each index lesion, the observers assessed the (a) mean (+/- standard deviation) of ADC, (b) enhancement ratio, and (c) subtracted images for the presence of enhancement (confidence score, 1-5). Histopathologic analysis of renal cell carcinomas (RCCs) and follow-up imaging for benign lesions were the reference standards. ADCs of benign lesions and RCCs were compared. Receiver operating characteristic (ROC) curve analysis was performed to assess the accuracy of DW imaging, enhancement ratio, and subtraction for the diagnosis of RCC. Results: A total of 64 lesions (mean diameter, 3.9 cm), including 38 benign T1 hyperintense cysts and 26 RCCs, were assessed. Mean ADCs of RCCs were significantly lower than those of benign cysts ([1.75 +/- 0.57] x 10(-3) mm(2)/sec vs [2.50 +/- 0.53] x 10(-3) mm(2)/sec, P < .0001). ADCs of solid and cystic portions of complex cystic RCCs were significantly different ([1.37 +/- 0.55] x 10(-3) mm(2)/sec vs [2.45 +/- 0.63] x 10(-3) mm(2)/sec, P < .0001). When data from both observers were pooled, area under the ROC curve, sensitivity, and specificity were 0.846, 71%, and 91%, respectively, for DW imaging; 0.865, 65%, and 96%, respectively, for enhancement ratio (at the excretory phase); and 0.861, 83%, and 89%, respectively, for subtraction (P = .48 and P = .85, respectively). The combination of DW imaging and subtraction resulted in area under the ROC curve, sensitivity, and specificity of 0.893, 87%, and 92%, respectively, with significantly improved reader confidence compared with subtraction alone (P = .041). CONCLUSION: The performance of DW imaging was equivalent to that of enhancement ratio in the characterization of T1 hyperintense renal lesions, with both methods having lower sensitivity than image subtraction without reaching significance

OBJECTIVE: This study aims to compare the image quality and potential diagnostic accuracy of paranasal sinus CT scans generated by flat panel cone beam CT at three specific data acquisition times. STUDY DESIGN: Prospective, single blinded analysis. SUBJECTS AND METHODS: Eleven patients without previous radiologic evaluation were selected based on history and findings suspicious for chronic sinusitis. Each patient was scanned at three different acquisition times: 10, 20, and 40 seconds. A panel of neuroradiologists and otolaryngologists, blinded to the scan acquisition time, individually reviewed images and rated overall image quality and visualization of specific anatomic sites. Image noise values were also calculated. Techniques were compared with a Wilcoxon matched-pairs signed ranks test. RESULTS: Compared to the 10-second acquisition time, the 40- and 20-second acquisition time techniques had significantly better image quality (P < 0.05) and image noise (P < 0.05). No difference in image quality and image noise existed between the 20- and 40-second techniques. No difference in visualization of specific anatomic structures existed between any of the time techniques. CONCLUSION: The quality of flat panel CT imaging of the sinuses directly relates to scan time and thus radiation dose

PURPOSE: Conventional noncontrast CT (NCCT) is insensitive to hyperacute cerebral infarction in the first 3 h. Our aim was to determine if CT perfusion (CTP) can improve diagnostic accuracy over NCCT for patients presenting with stroke symptoms in the 3-hour window. METHODS: Consecutive patients presenting to our emergency department with symptoms of ischemic stroke <3 h old and receiving NCCT and CTP as part of their triage evaluation were retrospectively reviewed. Patients with follow-up diffusion-weighted MRI (DWI) <7 days from ictus were included. Two readers rated the NCCT and CTP for evidence of acute infarct and its vascular territory. CTP selectively covered 24 mm of brain centered at the basal ganglia with low relative cerebral blood volume in a region of low cerebral blood flow or elevated time to peak as the operational definition for infarction. A third reader rated all follow-up DWI for acute infarct and its vascular territory as the reference standard. Sensitivity, specificity, and predictive values were calculated. An exact McNemar test and generalized estimating equations from a binary logistic regression model were used to assess the difference in detection rates between modalities. A two-sided p value <0.05 was considered significant. RESULTS: 100 patients were included. Sixty-five (65%) patients had follow-up DWI confirmation of acute infarct. NCCT revealed 17 (26.2%) acute infarcts without false positives. CTP revealed 42 (64.6%) acute infarcts with one false positive. Of the 23 infarcts missed on CTP, 10 (43.5%) were outside the volume of coverage while the remaining 13 (56.5%) were small cortical or lacunar type infarcts (<or=15 mm in size). CTP was significantly more sensitive (64.6 vs. 26.2%, p < 0.0001) and accurate (76.0 vs. 52%, p < 0.0001) and had a better negative predictive value (59.6 vs. 42.2%, p = 0.032) than NCCT. CONCLUSION: In a retrospective cohort of 100 patients with symptoms of hyperacute stroke in the 3-hour window, CTP provided improved sensitivity and accuracy over NCCT

OBJECTIVE: The purpose of this study was to evaluate morphologic features predictive of benign thyroid nodules. MATERIALS AND METHODS: From a registry of the records of 1,232 fine-needle aspiration biopsies performed jointly by the cytology and radiology departments at a single institution between 2005 and 2007, the cases of 650 patients were identified for whom both a pathology report and ultrasound images were available. From the alphabetized list generated, the first 500 nodules were reviewed. We analyzed the accuracy of individual sonographic features and of 10 discrete recognizable morphologic patterns in the prediction of benign histologic findings. RESULTS: We found that grouping of thyroid nodules into reproducible patterns of morphology, or pattern recognition, rather than analysis of individual sonographic features, was extremely accurate in the identification of benign nodules. Four specific patterns were identified: spongiform configuration, cyst with colloid clot, giraffe pattern, and diffuse hyperechogenicity, which had a 100% specificity for benignity. In our series, identification of nodules with one of these four patterns could have obviated more than 60% of thyroid biopsies. CONCLUSION: Recognition of specific morphologic patterns is an accurate method of identifying benign thyroid nodules that do not require cytologic evaluation. Use of this approach may substantially decrease the number of unnecessary biopsy procedures

OBJECTIVE: To assess cerebral blood flow (CBF) changes in patients with mild traumatic brain injury (MTBI) using an arterial spin labelling (ASL) perfusion MRI and to investigate the severity of neuropsychological functional impairment with respect to haemodynamic changes. MATERIALS AND METHODS: Twenty-one patients with MTBI and 20 healthy controls were studied at 3T MR. The median time since the onset of brain injury in patients was 24.6 months. Both patients and controls underwent a traditional consensus battery of neurocognitive tests. ASL was performed using true fast imaging with steady state precession and a flow-sensitive alternating inversion recovery preparation. Regional CBF were measured in both deep and cortical gray matter as well as white matter at the level of basal ganglia. RESULTS: The mean regional CBF was significantly lower in patients with MTBI (45.9 +/- 9.8 ml/100 g min(-1)) as compared to normal controls (57.1 +/- 8.1 ml/100 g min(-1); p = 0.002) in both sides of thalamus. The decrease of thalamic CBF was significantly correlated with several neurocognitive measures including processing and response speed, memory/learning, verbal fluency and executive function in patients. CONCLUSIONS: Haemodynamic impairment can occur and persist in patients with MTBI, the extent of which is more severe in thalamic regions and correlate with neurocognitive dysfunction during the extended course of disease

BACKGROUND: While immune system dysregulation has been postulated to play a role in Tourette's disorder (TD), most research has focused on the hypothesis of an autoimmune process similar to rheumatic fever. This study examined the potential role of cytokines, modulators of the immune system. We hypothesized that children with TD would have increased levels of tumor necrosis factor (TNF)-alpha, interleukin (IL)-12, IL-1 beta and IL-6, and decreased IL-2. We also explored whether comorbid obsessive compulsive disorder (OCD) had an effect on the cytokine profile of TD patients. METHOD: Thirty-two children and adolescents with TD (27 males, ages 7-18 years), 17 with comorbid OCD (14 males), and 16 healthy comparison subjects (7 males, ages 9-19), were enrolled. Plasma cytokines were examined using an enzyme-linked immunosorbent assay. The Mann-Whitney and binary logistic regression tests were used to compare the groups. RESULTS: Only patients with comorbid OCD (TD+OCD; n=17) had significantly elevated IL-12 plasma levels compared to controls (2.73+/-5.12 pg/ml vs. 0.55+/-0.88 pg/ml, rank statistic=222.5; p<0.04). IL-2 was significantly higher in the TD+OCD subgroup compared to the non-OCD TD subgroup (0.74+/-0.29 pg/ml vs. 0.49+/-0.24 pg/ml, rank statistics=108.5; p<0.03). There were no other significant cytokine differences between groups. CONCLUSIONS: Findings suggest a role for IL-12 and IL-2 in TD, and that the TD+OCD subgroup may involve different neuroimmunological functions than the TD-OCD subgroup. Larger studies with medication-free patients should follow

OBJECTIVE: Bilateral sequential cochlear implantation outcomes are dependent on many different factors. Newer technology in the second implanted ear may also contribute to outcome. This study examines the effect of cochlear implant technology on speech recognition outcomes in a population of adult patients who have undergone bilateral sequential implantation using different technologies in each ear. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral center. PATIENTS: Twenty adults who underwent bilateral sequential cochlear implantation with different technologies and processing strategies in each ear were patients for this study. Control Group A included patients (n = 8) who were simultaneously implanted, and Control Group B (n = 3) were patients who were sequentially implanted with the same technology. INTERVENTION: Bilateral sequential cochlear implantation. OUTCOME MEASURES: The outcome measure was the Consonant-Nucleus-Consonant monosyllabic word test administered in each implanted ear and in the binaural condition before and 1 year after operation. A multivariate analysis was performed to account for factors including duration of deafness, length of device usage, and severity of deafness. RESULTS: There was significant improvement from before to 1 year after the operation in word scores for the individual ears and in the binaural condition for all groups. All patients were consistent users of both devices, and the use of different technology in the second implanted ear did not affect the patients' ability to benefit from bilateral implantation despite the use of different devices and processing strategies. CONCLUSION: Bilateral sequential implantation with newer and/or differing technology in the second implanted ear did not reduce the benefits of bilateral stimulation and should not be considered a deterrent to second-sided implantation

BACKGROUND: Increased systemic cytokine levels, modulators of the immune system, have been repeatedly documented in adult and adolescent major depressive disorder (MDD). This preliminary study extends this work to test the role of cytokines in suicidal symptomatology in adolescent MDD. Hypotheses were that acutely suicidal depressed adolescents would have: (1) increased plasma levels of interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and IL-1beta, and (2) a proinflammatory/antiinflammatory cytokine imbalance (indexed by plasma IFN-gamma/IL-4), compared to nonsuicidal depressed adolescents and healthy controls. METHODS: Twelve suicidal adolescents with MDD (7 females [58%]; 5 medication-free/naive), 18 nonsuicidal adolescents with MDD (12 females [67%]; 8 medication-free/naive), and 15 controls (8 females [53%]) were enrolled. MDD had to be of at least 6 weeks duration, with a minimum severity score of 40 on the Children's Depression Rating Scale-Revised. Plasma cytokines were examined using enzyme-linked immunosorbent assays. Nonparametric tests were used to compare subject groups. RESULTS: Unexpectedly, suicidal adolescents with MDD had significantly decreased plasma TNF-alpha concentrations compared to nonsuicidal adolescents with MDD (1.33 +/- 2.95 pg/mL versus 30.9 +/- 110.9 pg/mL; p = 0.03). IFN-gamma was increased in both suicidal and nonsuicidal adolescents with MDD compared to controls (2.14 +/- 6.22 and 4.20 +/- 14.48 versus 0.37 +/- 0.64; p < 0.02, p = 0.005). Findings remained evident when controlled for age and gender. CONCLUSIONS: Our preliminary findings suggest that immune system dysregulation may be associated with suicidal symptomatology in adolescent MDD. These findings should be replicated in larger samples with medication-free adolescents