Academic Radiology - Articles in Press

Hyperpolarized 129Xe Magnetic Resonance Imaging: Tolerability in Healthy Volunteers and Subjects with Pulmonary Disease - Corrected Proof

2012-05-16

Rationale and Objectives: The objective of this study was to evaluate the tolerability of hyperpolarized 129Xe gas inhaled from functional residual capacity and magnetic resonance imaging in healthy subjects and those with pulmonary disease.Materials and Methods: Twelve healthy volunteers (mean age, 59 ± 17 years), seven subjects with asthma (mean age, 47 ± 7 years), 10 subjects with chronic obstructive pulmonary disease (mean age, 74 ± 4 years), three subjects with cystic fibrosis (mean age, 27 ± 10 years), and a single subject with radiation-induced lung injury (age, 66 years) were enrolled and evaluated over 43 visits with 136 anoxic inhalations of 500 mL 129Xe gas mixed with 500 mL 4He gas. Oxygen saturation and heart rate were monitored during the breath-hold and imaging; subjects were queried for adverse events (AEs) before and immediately following gas inhalation and for 24 hours after the last dose.Results: No subjects withdrew from the study or reported serious, hypoxic, or severe AEs. Over the course of 136 dose administrations, two mild AEs (1%) were reported in two different subjects (two of 33 [6%]). One of these AEs (light-headedness) was temporally related and judged as possibly related to 129Xe administration and resolved without treatment within 2 minutes. Statistically significant but clinically insignificant changes in oxygen saturation and heart rate were observed after inhalation (P < .001), and both resolved 1 minute later, with no difference between subject groups.Conclusions: Inhalation of hyperpolarized 129Xe gas and subsequent magnetic resonance imaging were well tolerated in healthy subjects and ambulatory subjects with obstructive and restrictive pulmonary disease.

Engineering and Radiology: Implications for Education - Corrected Proof

Richard B. Gunderman, Todd A. Rickett — 2012-05-16

There is considerable common ground between radiology and engineering. The imaging equipment radiologists use each day was designed and is maintained by engineers. Innovation in radiology, such as the development of a new magnetic resonance imaging pulse sequence or a new modality such as positron emission tomography/magnetic resonance imaging, requires close collaboration between radiologists and engineers. In fact, with a few notable exceptions such as Godfrey Hounsfield, engineers are frequently the unsung heroes of medical progress.

Radiofrequency Ablation of Retroperitoneal Metastatic Lymph Nodes from Hepatocellular Carcinoma - Corrected Proof

Fei Gao, Yangkui Gu, Jinhua Huang, Ming Zhao, Peihong Wu — 2012-05-16

Rationale and Objectives: To retrospectively evaluate effectiveness and safety of radiofrequency (RF) ablation with retroperitoneal metastatic lymph nodes from hepatocellular carcinoma (HCC).Materials and Methods: Thirty-two patients with retroperitoneal metastatic lymph node recurrence from HCC were enrolled in our study and the patients stratified into two groups based on the treatment. Nineteen patients in Group A were percutaneously treated and each metastatic lymph node was ablated with computed tomographic (CT) guidance. Thirteen patients in Group B only underwent RF ablation for hematogenous metastases, but did not undergo RF ablation or any other treatment for metastatic lymph nodes. Follow-up contrast material–enhanced CT or positron emission tomographic scans were reviewed and Kaplan-Meier survival estimates were analyzed.Results: There were no significant differences between characteristics of the two groups. Kaplan-Meier analysis indicated the patients of Group A had an overall survival of 26.3% at 1 year compared with 7.7% for those of Group B. Mantel-Cox log rank test showed the 1-year survival rate of Group A was significantly higher than that of Group B (P = .029). In Group A, the local control rate of 3, 6, 10, and 15 months was 78.9%, 73.3%, 41.7%, and 25.0%, respectively. Sixteen, 12, 6, and 2 patients showed no evidence of local progression for 3, 6, 10, and 15 months, respectively. There was no thermal injury of gastrointestinal tract or bile duct during RF ablation in all the 19 patients of Group A.Conclusion: RF ablation is effective and may be safely applied to retroperitoneal metastatic lymph nodes from HCC.

Semi-Automatic Segmentation Software for Quantitative Clinical Brain Glioblastoma Evaluation - Corrected Proof

2012-05-16

Rationale and Objectives: Quantitative measurement provides essential information about disease progression and treatment response in patients with glioblastoma multiforme (GBM). The goal of this article is to present and validate a software pipeline for semi-automatic GBM segmentation, called AFINITI (Assisted Follow-up in NeuroImaging of Therapeutic Intervention), using clinical data from GBM patients.Materials and Methods: Our software adopts the current state-of-the-art tumor segmentation algorithms and combines them into one clinically usable pipeline. Both the advantages of the traditional voxel-based and the deformable shape-based segmentation are embedded into the software pipeline. The former provides an automatic tumor segmentation scheme based on T1- and T2-weighted magnetic resonance (MR) brain data, and the latter refines the segmentation results with minimal manual input.Results: Twenty-six clinical MR brain images of GBM patients were processed and compared with manual results. The results can be visualized using the embedded graphic user interface.Conclusion: Validation results using clinical GBM data showed high correlation between the AFINITI results and manual annotation. Compared to the voxel-wise segmentation, AFINITI yielded more accurate results in segmenting the enhanced GBM from multimodality MR imaging data. The proposed pipeline could be used as additional information to interpret MR brain images in neuroradiology.

Radiofrequency Ablation of the Liver: Effect of Variation of Portal Venous Blood Flow on Lesion Size in an In-vitro Perfused Bovine Liver - Corrected Proof

Liping Huang, Gerald D. Dodd III, Anthony C. Lanctot — 2012-05-16

Rationale and Objectives: An in vitro perfused bovine liver model was used to evaluate the relationship between the sizes of radiofrequency ablation lesions and variation in portal venous blood flow.Materials and Methods: Fourteen bovine livers were perfused with autologous heparinized blood at 37°C and 40% to 50% oxygenation via the portal vein. Flow rates were adjusted from 10 to 50 mL/min/100 g tissue. A 480-kHz generator and a 3.0-cm monopolar internally cooled electrode were used to create 57 ablations. The long-axis diameter, short-axis diameter (SAD), and volume of each ablation zone were measured and calculated from the dissected livers. Correlations between SAD, long-axis diameter, and volume versus blood flow were assessed using linear regression analysis.Results: SAD and lesion volume demonstrated inverse linear correlations with blood flow (for SAD, y = −0.044x + 3.925, r = 0.836, P < .001; for volume, y = −0.556x + 31.574, r = 0.842, P < .001). A 10 mL/min/100 g change in flow rate produced an average 4.4 ± 0.4 mm change in SAD and an average 5.6 ± 0.5 cm3 change in volume. Long-axis diameter was not correlated with blood flow (y = −0.7694x + 4.1899, r = 0.2173, P = .111).Conclusions: The SAD and volume of radiofrequency ablation lesions have statistically significant inverse linear correlations with portal venous blood flow, with an average 4.4-mm change in SAD and an average 5.6-cm3 change in volume for each 10 mL/min/100 g change in flow rate.

Correlation between Dynamic Contrast-enhanced Perfusion MRI Relative Cerebral Blood Volume and Vascular Endothelial Growth Factor Expression in Meningiomas - Corrected Proof

Daniel T. Ginat, Rajiv Mangla, Gabrielle Yeaney, Pamela W. Schaefer, Henry Wang — 2012-05-16

Purpose: To determine whether there is a correlation between vascular endothelial growth factor (VEGF) expression and cerebral blood flow (CBV) measurements in dynamic contrast-enhanced susceptibility perfusion magnetic resonance imaging (MRI) and to correlate the perfusion characteristics in high- versus low-grade meningiomas.Methods and Materials: A total of 48 (24 high-grade and 24 low-grade) meningiomas with available dynamic susceptibility–weighted MRI were retrospectively reviewed for maximum CBV and semiquantitative VEGF immunoreactivity. Correlation between normalized CBV and VEGF was made using the Spearman rank test and comparison between CBV in high- versus low-grade meningiomas was made using the Wilcoxon test.Results: There was a significant (P = .01) correlation between normalized maximum CBV and VEGF scores with a Spearman correlation coefficient of 0.37. In addition, there was a significant (P < .01) difference in normalized maximum CBV ratios between high-grade meningiomas (mean 12.6; standard deviation 5.2) and low-grade meningiomas (mean 8.2; standard deviation 5.2).Conclusion: The data suggest that CBV accurately reflects VEGF expression and tumor grade in meningiomas. Perfusion-weighted MRI can potentially serve as a useful biomarker for meningiomas, pending prospective studies.

Improved Detection of Parenchymal Cysticercal Lesions in Neurocysticercosis with T2*-weighted Angiography Magnetic Resonance Imaging - Corrected Proof

2012-05-14

Rationale and Objectives: Magnetic resonance imaging (MRI) is an important tool for the diagnosis and management of various central nervous system infections. In the present study, we investigated the role of T2*-weighted angiography (SWAN) imaging in the diagnosis of neurocysticercosis (NCC) viz-a-viz conventional MRI.Methods: Symptomatic (n = 46) and asymptomatic (n = 88) cases from a pig-farming community were imaged using both conventional and SWAN MRI between July 2009 and May 2011. Two experienced neuroradiologists independently reviewed all the images to characterize the lesions as well as detection of the scolex.Results: A total of 250 lesions were detected in 70 individuals. On conventional MRI, the lesion and scolex visibility was 82.4% (206/250) and 60% (150/250), respectively, which increased to 96.8% and 81%, respectively, using SWAN imaging. On combining SWAN with conventional MRI, the scolex visibility increased to 85% (213/250) of the total 250 lesions detected. Overall, adding SWAN to conventional MRI increased the lesion detection and scolex visibility up to 18% (206 vs. 250) and 30% (150 vs. 213), respectively.Conclusion: SWAN imaging when added to the conventional MRI protocol for population screening for NCC in endemic regions improves both lesion detection and definitive diagnosis of neurocysticercosis.

CT Scans of the Chest in Carriers of Human T-cell Lymphotropic Virus Type 1: Presence of Interstitial Pneumonia - Corrected Proof

2012-05-14

Rationale and Objectives: To evaluate pulmonary findings on computed tomography (CT) scans in carriers of human T-lymphotropic virus type 1 (HTLV-1).Materials and Methods: This retrospective study was approved by the Institutional Review Board at each institution, and informed consent was waived. Patients who were diagnosed with adult T-cell lymphoma/leukemia or collagen vascular disease were excluded from the study. Chest CT of 106 HTLV-1 carriers (54 females and 52 males; age range 44–94 years) were initially evaluated by two chest radiologists. Assessed CT findings included centrilobular nodules, thickening of bronchovascular bundles, ground-glass opacity, bronchiectasis, interlobular septal thickening, consolidation, honeycombing, crazy-paving appearance, enlarged lymph nodes, pleural effusion, and pericardial effusion. Three chest radiologists secondarily evaluated the CT scans with the abnormal findings to judge the presence of interstitial pneumonia patterns or a bronchiolitis/bronchitis pattern.Results: Abnormal CT findings were found in 65 (61.3%) patients, including ground-glass opacity (n = 33), bronchiectasis (n = 28), centrilobular nodules (n = 25), and interlobular septal thickening (n = 19). Honeycombing (n = 5) and crazy-paving appearance (n = 3) were also observed. Based on the CT findings, 10 subjects were diagnosed with interstitial pneumonia (usual interstitial pneumonia pattern, n = 3; nonspecific interstitial pneumonia pattern, n = 5; organizing pneumonia pattern, n = 2; respectively). Twenty subjects were diagnosed with the bronchitis/bronchiolitis pattern.Conclusion: Although the bronchiolitis/bronchitis pattern is predominant on chest CT in HTLV-1 carriers, the HTLV-1 infection is associated with various interstitial pneumonias.

Cross-specialty Integrated Resident Conferences: An Educational Approach to Bridging the Gap - Corrected Proof

2012-05-14

Rationale and Objectives: Radiologists play a pivotal role in patient management, primarily through interacting with referring clinicians. Despite this extensive cross-specialty interaction, radiology resident education rarely involves direct education from clinicians outside the department. We surveyed resident attitudes toward integrated conferences with subspecialty referring physicians both before and after a pilot lecture series at our institution.Materials and Methods: Three thoracic-themed multidisciplinary conferences were organized, which involved a variety of clinicians lecturing during normal resident conference times. Resident surveys were administered before and after the complete lectures series as well as immediately after each individual lecture.Results: The prelecture series survey indicated residents felt neutral about their confidence in knowing what clinicians want from radiology reports and the current level of “clinician-focus” in the curriculum. Residents indicated a desire for more clinician involvement in lectures. After completion of the series, residents expressed that the integrated conferences were useful and that they had greater confidence in understanding the clinicians' expectation of reports. Resident interest in clinician participation in lectures was higher after series completion. Most residents indicated that prespecified, self-identified learning objectives were met by the lectures. After the completion of the series, most residents indicated that they wanted the series to continue, with the most commonly indicated desired frequency being once or twice a month.Conclusion: Subspecialty clinician participation in a cross-specialty integrated resident lecture series was highly favored and well received. An “Integrated Clinical Lecture Series” may be a beneficial addition to radiology residency curriculums.

Systems for Lung Volume Standardization during Static and Dynamic MDCT-based Quantitative Assessment of Pulmonary Structure and Function - Corrected Proof

Matthew K. Fuld, Randall W. Grout, Junfeng Guo, John H. Morgan, Eric A. Hoffman — 2012-05-03

Rationale and Objectives: Multidetector-row computed tomography (MDCT) has emerged as a tool for quantitative assessment of parenchymal destruction, air trapping (density metrics), and airway remodeling (metrics relating airway wall and lumen geometry) in chronic obstructive pulmonary disease (COPD) and asthma. Critical to the accuracy and interpretability of these MDCT-derived metrics is the assurance that the lungs are scanned during a breathhold at a standardized volume.Materials and Methods: A computer monitored turbine-based flow meter system was developed to control patient breathholds and facilitate static imaging at fixed percentages of the vital capacity. Because of calibration challenges with gas density changes during multibreath xenon CT, an alternative system was required. The design incorporated dual rolling seal pistons. Both systems were tested in a laboratory environment and human subject trials.Results: The turbine-based system successfully controlled lung volumes in 32/37 subjects, having a linear relationship for CT measured air volume between repeated scans: for all scans, the mean and confidence interval of the differences (scan1-scan2) was −9 mL (−169, 151); for total lung capacity alone 6 mL (−164, 177); for functional residual capacity alone, −23 mL (−172, 126). The dual-piston system successfully controlled lung volume in 31/41 subjects. Study failures related largely to subject noncompliance with verbal instruction and gas leaks around the mouthpiece.Conclusion: We demonstrate the successful use of a turbine-based system for static lung volume control and demonstrate its inadequacies for dynamic xenon CT studies. Implementation of a dual-rolling seal spirometer has been shown to adequately control lung volume for multibreath wash-in xenon CT studies. These systems coupled with proper patient coaching provide the tools for the use of CT to quantitate regional lung structure and function. The wash-in xenon CT method for assessing regional lung function, although not necessarily practical for routine clinical studies, provides for a dynamic protocol against which newly emerging single breath, dual-energy xenon CT measures can be validated.

Identification of Noncalcified Plaque in Young Persons with Diabetes: An Opportunity for Early Primary Prevention of Coronary Artery Disease Identified with Low-dose Coronary Computed Tomographic Angiography - Corrected Proof

2012-04-30

Purpose: Coronary computed tomographic angiography (CTA) is a valuable tool for assessing coronary artery disease (CAD). Although statin use is widely recommended for persons with diabetes older than age 40, little is known about the presence and severity of CAD in younger patients with diabetes mellitus (DM). We evaluated coronary artery calcium (CAC) and coronary CTA in young persons with both DM1 and DM2 in an attempt to detect the earliest objective evidence of arteriosclerosis eligible for primary prevention.Methods and Materials: We prospectively enrolled 40 persons with DM (25 type 1 and 15 type 2) between the ages of 19 and 35 presenting with diabetes for 5 years or longer. All patients underwent coronary CTA and CAC scans to evaluate for early atherosclerotic disease. Each plaque in the coronary artery was classified as noncalcified or calcified-mixed. We also evaluated all segments with stenosis, dividing them into mild (<50%), moderate (50–70%), and severe (>70%).Results: The average age of the DM1 subjects were 26 ± 4 (SD) years and 30 ± 4 years for DM2 patients (P < .01), with duration of diabetes of 8 ± 5 years and average HbA1c% of 8.7 ± 1.6 (norm = 4.6–6.2). Abnormal scans were present in 57.5%, noncalcified in 35% and calcified-mixed plaque in 22.5%. Persons with DM2 had a higher prevalence of positive coronary CTA scans than DM1: 80% versus 44% (P < .03) and more positive CAC scores 53% versus 4%, (P < .01). The total segment score of 2.1 ± 3.4 (P < .01) and total plaque score 1.9 ± 2.8 (P < .01) were highly correlated to each other. Plaque was almost uniformly absent below age 25, and became increasingly common in individuals over the age of 25 years for both groups. The average radiation exposure was 2.5 ± 1.3 mSv.Conclusion: Our study verifies that early CAD can be diagnosed with coronary CTA and minimal radiation exposure in young adults with DM. A negative CAC score was not sufficient to exclude early CAD as we observed a preponderance of noncalcified plaque in this cohort. Coronary CTA in young DM patients older than age 25 may provide earlier identification of disease than does a CAC because only noncalcified plaque is frequently present. Coronary CTA provides an opportunity to consider initiation of earlier primary CAD prevention rather than waiting for the age of 40 as currently recommended by the American Diabetes Association guidelines.

Comparison of Radiologist Performance with Photon-Counting Full-Field Digital Mammography to Conventional Full-Field Digital Mammography - Corrected Proof

Elodia B. Cole, Alicia Y. Toledano, Mats Lundqvist, Etta D. Pisano — 2012-04-26

Rationale and Objectives: The purpose of this study was to assess the performance of a MicroDose photon-counting full-field digital mammography (PCM) system in comparison to full-field digital mammography (FFDM) for area under the receiver-operating characteristic (ROC) curve (AUC), sensitivity, specificity, and feature analysis of standard-view mammography for women presenting for screening mammography, diagnostic mammography, or breast biopsy.Materials and Methods: A total of 133 women were enrolled in this study at two European medical centers, with 67 women who had a pre-existing 10–36 months FFDM enrolled prospectively into the study and 66 women who underwent breast biopsy and had screening PCM and diagnostic FFDM, including standard craniocaudal and mediolateral oblique views of the breast with the lesion, enrolled retrospectively. The case mix consisted of 49 cancers, 17 biopsy-benign cases, and 67 normal cases. Sixteen radiologists participated in the reader study and interpreted all 133 cases in both conditions, separated by washout period of ≥4 weeks. ROC curve and free-response ROC curve analyses were performed for noninferiority of PCM compared to FFDM using a noninferiority margin Δ value of 0.10. Feature analysis of the 66 cases with lesions was conducted with all 16 readers at the conclusion of the blinded reads. Mean glandular dose was recorded for all cases.Results: The AUC for PCM was 0.947 (95% confidence interval [CI], 0.920–0.974) and for FFDM was 0.931 (95% CI, 0.898–0.964). Sensitivity per case for PCM was 0.936 (95% CI, 0.897–0.976) and for FFDM was 0.908 (95% CI, 0.856–0.960). Specificity per case for PCM was 0.764 (95% CI, 0.688–0.841) and for FFDM was 0.749 (95% CI, 0.668–0.830). Free-response ROC curve figures of merit were 0.920 (95% CI, 0.881–0.959) and 0.903 (95% CI, 0.858–0.948) for PCM and FFDM, respectively. Sensitivity per lesion was 0.903 (95% CI, 0.846–0.960) and 0.883 (95% CI, 0.823–0.944) for PCM and FFDM, respectively. The average false-positive marks per image of noncancer cases were 0.265 (95% CI, 0.171–0.359) and 0.281 (95% CI, 0.188–0.374) for PCM and FFDM, respectively. Noninferiority P values for AUC, sensitivity (per case and per lesion), specificity, and average false-positive marks per image were all statistically significant (P < .001). The noninferiority P value for free-response ROC was <.025, from the 95% CI for the difference. Feature analysis resulted in PCM being preferred to FFDM by the readers for ≥70% of the cases. The average mean glandular dose for PCM was 0.74 mGy (95% CI, 0.722–0.759 mGy) and for FFDM was 1.23 mGy (95% CI, 1.199–1.262 mGy).Conclusions: In this study, radiologist performance with PCM was not inferior to that with conventional FFDM at an average 40% lower mean glandular dose.

CAD-associated Reader Error in CT Colonography - Corrected Proof

Vadim S. Koshkin, J. Louis Hinshaw, Kristen Wroblewski, Abraham H. Dachman — 2012-04-26

Rationale and Objectives: Computed tomographic colonographic interpretation with computer-aided detection (CAD) may be superior to unaided viewing, although polyp characteristics may influence accuracy. Reader error due to polyp characteristics was evaluated in a multiple-case, multiple-reader trial of computed tomographic colonography with CAD.Materials and Methods: Two experts retrospectively reviewed 52 positive cases (74 polyps) and categorized them as hard, moderate, or easy to detect. Each case was evaluated without and with CAD. Features that may influence a reader's ability to detect a polyp or to accept or reject a CAD mark were tabulated. The association between polyp characteristics and detection rates in the trial was assessed. The difference in detection rates (CAD vs unassisted) was calculated, and regression analysis was performed.Results: Of 64 polyps found by CAD, experts categorized 20 as hard, 28 as moderate, and 16 as easy to detect. Reader characterization errors predominated (47.3%) over other errors. Factors associated with lower detection rates included small size, flat morphology, and resemblance to a thickened fold. CAD was superior for polyps resembling lipomas compared to those that did not resemble lipomas (average increase in detection rate with CAD, 12.8% vs 5.5%; P < .05).Conclusions: Polyp characteristic may impair computed tomographic colonographic interpretation augmented by CAD. Readers can avoid errors of measurement by evaluating diminutive polyp candidates with sample measurements. Caution should be taken when evaluating focally thick folds and when using visual impression to dismiss a polyp candidate as a lipoma when it is submerged in densely tagged fluid.

Improved Understanding of Human Anatomy through Self-guided Radiological Anatomy Modules - Corrected Proof

Andrew W. Phillips, Sandy G. Smith, Callum F. Ross, Christopher M. Straus — 2012-04-26

Rationale and Objective: To quantifiably measure the impact of self-instructed radiological anatomy modules on anatomy comprehension, demonstrated by radiology, gross, and written exams.Materials and Methods: Study guides for independent use that emphasized structural relationships were created for use with two online radiology atlases. A guide was created for each module of the first year medical anatomy course and incorporated as an optional course component. A total of 93 of 96 eligible students participated. All exams were normalized to control for variances in exam difficulty and body region tested. An independent t-test was used to compare overall exam scores with respect to guide completion or incompletion. To account for aptitude differences between students, a paired t-test of each student's exam scores with and without completion of the associated guide was performed, thus allowing students to serve as their own controls.Results: Twenty-one students completed no study guides; 22 completed all six guides; and 50 students completed between one and five guides. Aggregate comparisons of all students' exam scores showed significantly improved mean performance when guides were used (radiology, 57.8% [percentile] vs. 45.1%, P < .001; gross, 56.9% vs. 46.5%, P = .001; written, 57.8% vs. 50.2%, P = .011). Paired comparisons among students who completed between one and five guides demonstrated significantly higher mean practical exam scores when guides were used (radiology, 49.3% [percentile] vs. 36.0%, P = .001; gross, 51.5% vs. 40.4%, P = .005), but not higher written scores.Conclusions: Radiological anatomy study guides significantly improved anatomy comprehension on radiology, gross, and written exams.

Awareness and Level of Knowledge of Interventional Radiology Among Medical Students at a Canadian Institution - Corrected Proof

Lauren O'Malley, Sriharsha Athreya — 2012-04-23

Purpose: To assess the awareness and level of exposure of interventional radiology (IR) among medical students at a Canadian medical school. To understand how IR can be better described and introduced to medical students.Materials and Methods: Electronic anonymous surveys were sent to 542 medical students in their first, second, and third years at a Canadian 3-year medical school. A total of 103 students (19%) responded. Each survey contained 17 questions assessing knowledge, interest, and perception of IR.Results: Fifty-three percent (55/103) of respondents reported “poor” knowledge of IR and only 18% (19/103) said they would consider a career in IR. Respondents cited lack of knowledge (48%, 37/77) or lack of interest (43%, 33/77) as the main reasons why they would not consider IR as a career. Although 92% (95/103) of respondents could name at least one IR procedure, many (54%, 56/103) were unclear as to the duties of an interventional radiologist within the hospital. Seventy-four percent (76/103) of students stated that a mandatory 2-week rotation in radiology during clerkship would be beneficial, whereas 71% (73/103) stated that they would be interested in a 2-week IR selective during their mandatory core surgery rotation.Conclusions: The knowledge and exposure to IR in medical school is limited. Students were eager to learn more about IR and expressed a desire for more exposure. Early exposure of medical students to IR should be introduced to attract future interventional radiologists as well as increase awareness among future referring physicians.

Diagnosis of Breast Diseases: Integrating the Findings of Clinical Presentation, Mammography, and Ultrasound - Corrected Proof

Karen C. Chen — 2012-04-23

This book is an authorized, revised, and enlarged translation of the second German edition published and copyrighted in 2006 by the same publisher. It is a comprehensive text of the clinical and radiological management of breast diseases. Diagnosis of Breast Diseases was largely written by a single author, Volker Barth, and has contributions from five colleagues at the Breast Imaging Center, Esslingen, Germany, and two specialists from a different institution. The authors provide the radiologist with the fundamentals of breast imaging for the differential diagnosis of breast diseases using a case-based approach with abundant illustrations, tables, photographs, mammograms, and ultrasound.

Computed Tomography Scans in the Evaluation of Fatty Liver Disease in a Population Based Study: The Multi-Ethnic Study of Atherosclerosis - Corrected Proof

2012-04-23

Rationale and Objectives: Fatty liver disease is a common clinical entity in hepatology practice. This study evaluates the prevalence and reproducibility of computed tomography (CT) measures for diagnosis of fatty liver and compares commonly used CT criteria for the diagnosis of liver fat.Materials and Methods: The study includes 6814 asymptomatic participants from a population-based sample. The ratio of liver-to-spleen (L/S) Hounsfield units (HU) <1.0 and liver attenuation <40 HU were used for diagnosing and assessing the severity of liver fat content. Participants with heavy alcohol intake (>7 drinks/week for women and >14 drinks/week for men) were excluded. Final analysis was performed on participants where images of both liver and spleen were available on the scans.Results: The overall prevalence of fatty liver (4175 subjects included in final analysis) was 17.2% (using L/S ratio <1.0), with 6.3% (with <40 HU cutoff) of the population having moderate to severe steatosis (>30% liver fat content). The prevalence was high in participants with dyslipidemia (70.4%), hypertension (56.8%), and obesity (53%). Diabetic patients had 24.1% prevalence of fatty liver. The prevalence provided by L/S ratio <1.0 (17.2%) was comparable to prevalence provided by <51 HU (17.3%), whereas prevalence obtained by <40 HU (6.3%) cutoff corresponded to L/S ratio of <0.8 (6.5%). The measurements of liver and spleen HU attenuations were highly reproducible (0.96, 0.99 and 0.99, 0.99 for intra- and inter-reader variability, respectively) in a sample of 100 scans.Conclusion: Fatty liver can be reliably diagnosed using nonenhanced CT scans.

Inflammatory Bowel Disease in Children and Adolescents: Assessing the Diagnostic Performance and Interreader Agreement of Magnetic Resonance Enterography Compared to Histopathology - Corrected Proof

2012-04-23

Rationale and Objectives: The purpose of this study was to determine the accuracy of magnetic resonance enterography (MRE) compared to histopathology in the evaluation of pediatric inflammatory bowel disease and to assess interreader reliability for image interpretation.Materials and Methods: All magnetic resonance enterography studies performed for known or suspected inflammatory bowel disease between July 2009 and July 2010 were retrospectively reviewed by two pediatric radiologists. Exams were evaluated for signs of enteric inflammation and extraenteric disease. A five-point, Likert-type scale was used to assess the overall likelihood of active inflammation, with scores ≥ 3 considered positive. Cohen's κ coefficient was calculated to assess interreader agreement. A subset of patients who had undergone ileocolonoscopy or surgery with confirmed histopathology within 45 days of MRE were used to assess the accuracy of MRE for detecting active inflammation in the terminal ileum and large bowel.Results: A total of 91 magnetic resonance enterography studies were reviewed. Of these, 45 had comparison histopathology within 45 days. The overall sensitivity of MRE for detecting active inflammation compared to ileocolonoscopy was 92% for both readers, while specificity was 100% for reader 1 and 75% for reader 2. Of the individual parameters evaluated, mucosal hyperenhancement and bowel wall thickening were the most sensitive indicators of active inflammation, each having sensitivity of 86% and specificity of 88%. Cohen's κ coefficient was 0.59, indicating moderate agreement between the readers.Conclusions: MRE has high overall diagnostic accuracy for detecting active bowel inflammation in pediatric patients compared to ileocolonoscopy and demonstrates moderate interreader reliability.

A Comparative Study of HRCT Image Metrics and PFT Values for Characterization of ILD and COPD - Corrected Proof

2012-04-20

Rationale and Objectives: The aim of this study was to compare the performance of various image-based metrics computed from thoracic high-resolution computed tomography (HRCT) with data from pulmonary function testing (PFT) in characterizing interstitial lung disease (ILD) and chronic obstructive pulmonary disease (COPD).Materials and Methods: Fourteen patients with ILD and 11 with COPD had undergone both PFT and HRCT within 3 days. For each patient, 93 image-based metrics were computed, and their relationships with the 21 clinically used PFT parameters were analyzed using a minimal-redundancy-maximal-relevance statistical framework. The first 20 features were selected among the total of 114 mixed image metrics and PFT values in the characterization of ILD and COPD.Results: Among the best-performing 20 features, 14 were image metrics, derived from attenuation histograms and texture descriptions. The highest relevance value computed from PFT parameters was 0.47, and the highest from image metrics was 0.52, given the theoretical bound as [0, 0.69]. The ILD or COPD classifier using the first four features achieved a 1.92% error rate.Conclusions: Some image metrics are not only as good discriminators as PFT for the characterization of ILD and COPD but are also not redundant when PFT values are provided. Image metrics of attenuation histogram statistics and texture descriptions may be valuable for further investigation in computer-assisted diagnosis.

Utility of Apparent Diffusion Coefficient Ratios in Distinguishing Common Pediatric Cerebellar Tumors - Corrected Proof

2012-04-19

Rationale and Objectives: The aim of this study was to identify clinically useful tumor/normal brain apparent diffusion coefficient (ADC) ratios for distinguishing common pediatric cerebellar tumors.Materials and Methods: Review of medical records revealed 79 patients with cerebellar tumors who underwent preoperative magnetic resonance imaging, including diffusion-weighted imaging sequences, and surgery. There were 31 pilocytic astrocytomas, 27 medulloblastomas, 14 ependymomas, and seven atypical teratoid/rhabdoid tumors. ADC values were measured by placing regions of interest on the solid tumor and normal brain parenchyma by two reviewers. Tumor/normal brain ADC ratios were calculated.Results: Mean ADC values of the pilocytic astrocytomas were greater than those of ependymomas, whose mean ADC values were greater than those of medulloblastomas and atypical teratoid/rhabdoid tumors. Using a tumor/normal brain ADC ratio threshold of 1.70 to distinguish pilocytic astrocytomas from ependymomas, sensitivity of 92% and specificity of 79% were achieved. A tumor/normal brain ADC ratio threshold of 1.20 enabled the sorting of ependymomas from medulloblastomas with sensitivity of 93% and specificity of 88%.Conclusions: Tumor/normal brain ADC ratios allow the distinguishing of common pediatric cerebellar tumors.

MR Elastography in Renal Transplant Patients and Correlation with Renal Allograft Biopsy: A Feasibility Study - Corrected Proof

2012-04-16

Rationale and Objectives: Magnetic resonance elastography (MRE) images the propagation of mechanical shear waves in tissue and uses that information to generate quantitative measures of tissue stiffness. Hepatic MRE has been successfully performed in thousands of patients, with good correlation between histologic grade of fibrosis and tissue stiffness. There has been no prior investigation of the utility of MRE for the assessment of kidney transplants. The aims of this study were to prospectively evaluate the feasibility of MRE in a small group of kidney transplant recipients and to correlate the measured magnetic resonance elastographic stiffness values with biopsy-proven histopathologic fibrosis.Materials and Methods: MRE of renal transplants was performed in 11 patients returning for protocol allograft biopsies. Calculated tissue stiffness values were compared to histologic degree of fibrosis in nine of the 11 patients.Results: The mean stiffness of two patients with moderate interstitial fibrosis was higher than the mean of six patients with mild interstitial fibrosis, but not significantly so (90 Hz, P = .12; 120 Hz, P = .17; 150 Hz, P = .26). The mean stiffness of the two patients with moderate interstitial fibrosis was slightly greater than the mean of one patient with no significant interstitial fibrosis at 90 Hz (P = .78) and slightly less at 120 and 150 Hz (P = .88 and P = .76). The mean stiffness of the six patients with mild interstitial fibrosis did not differ significantly from that of the one patient with no interstitial fibrosis (90 Hz, P = .35; 120 Hz, P = .22; 150 Hz, P = .16).Conclusions: Preliminary results demonstrate feasibility and support known multifactorial influences on renal stiffness.

Proton MR Spectroscopy of Central Neurocytoma Using Short and Long Echo Time: New Proofs for the Existence of Glycine and Glutamate - Corrected Proof

2012-04-16

Rationale and Objectives: Central neurocytomas (CNCs) are rare benign tumors typically located in the lateral ventricle of the central nervous system. The authors report five patients with CNCs and review 16 previously published studies that included 52 patients with CNCs to explore the magnetic resonance spectroscopic features of CNCs.Materials and Methods: Five patients with CNCs were retrospectively reviewed. They were examined using point-resolved spectroscopic series with short and/or long echo times. The integrals of choline, creatine, and the 3.55-ppm peak were determined using Magnetic Resonance User Interface software, and the metabolite ratios relative to creatine were obtained. In two cases, T2 relaxation times of choline and the metabolite resonance at 3.55 ppm were calculated using data points acquired with different echo times and an exponential decay model.Results: Consistent with previously published studies, all five patients showed highly increased choline and reduced N-acetylaspartate and creatine. Four patients in the present study and 35 in published data demonstrated prominent peaks at 3.55 ppm, which were assigned to glycine because of its relaxation pattern and long T2 relaxation time. In addition, increased in vivo glutamate and glutamine was also confirmed in three patients examined with short echo times. Alanine and lactate peaks were observed in three and two patients, respectively.Conclusions: The present study shows that the 3.55-ppm peak characteristic of CNC should be assigned to glycine according to its T2 relaxation time. Besides increased glycine and choline, the presence of glutamate or glutamine, which appears on series with short echo times, may further confirm the diagnosis of CNC.

Healthy Aging: An Automatic Analysis of Global and Regional Morphological Alterations of Human Brain - Corrected Proof

2012-04-16

Rationale and Objectives: Morphologic changes of the human brain during healthy aging provide useful reference knowledge for age-related brain disorders. The aim of this study was to explore age-related global and regional morphological changes of healthy adult brains.Materials and Methods: T1-weighted magnetic resonance images covering the entire brain were acquired for 314 subjects. Image processing of registration, segmentation, and surface construction were performed to calculate the volumes of the cerebrum, cerebellum, brain stem, lateral ventricle, and subcortical nuclei, as well as the surface area, mean curvature index, cortical thickness of the cerebral cortex, and subjacent white matter volume using FreeSurfer software. Mean values of each morphologic index were calculated and plotted against age group for sectional analysis. Regression analysis was conducted using SPSS to investigate the age effects on global and regional volumes of human brain.Results: Overall global and regional volume loss was observed for the entire brain during healthy aging. Moderate atrophy was observed in subcortical gray matter structures, including the thalamus (R2 = 0.476, P < .001), nucleus accumbens (R2 = 0.525, P < .001), pallidum (R2 = 0.461, P < .001), and putamen (R2 = 0.533, P < .001). The volume of hippocampus showed a slight increase by 40 years of age, followed by a relatively faster decline after the age of 50 years (R2 = 0.486, P < .001). Surface area and mean curvature were less affected by aging relative to cortical thickness and subjacent white matter volume. Significant cortical thinning was mainly found in the parietal (R2 = 0.553, P < .001) and insula regions (R2 = 0.405, P < .001).Conclusions: Morphologic alterations of human brain manifested regional heterogeneity in the scenario of general volume loss during healthy aging. The age effect on the hippocampus demonstrated a unique evolution. These findings provide informative reference knowledge that may help in identifying and differentiating pathologic aging and other neurologic disorders.

Thoracic and Abdominal Aortic Diameter Measurement by MRI Using Plain Axial Volumetric Interpolated Breath-hold Examination in Epidemiologic Research: A Validation Study - Corrected Proof

2012-04-16

Rationale and Objectives: This study evaluates the validity and reliability of measuring the diameters of the thoracic and abdominal aorta from plain volumetric interpolated breath-hold examination (VIBE) images.Materials and Methods: The study included 50 male subjects from the population-based Study of Health in Pomerania. They underwent imaging of the thoracic and abdominal aorta at 1.5 Tesla using a contrast-enhanced magnetic resonance angiography (CE-MRA) and plain VIBE sequence. Diameters were measured at five predefined anatomic sites from reformatted orthogonal CE-MRA images and axial plain VIBE images. The measurements were validated using Pearson correlation and Bland-Altman analysis. The Bland-Altman method was also used to assess reliability.Results: Comparison of the diameters measured from CE-MRA and VIBE images revealed strong correlation for the ascending, descending, suprarenal, and infrarenal aorta with r = 0.95 (P < .0001), r = 0.88 (P < .0001), 0.92 (P < .0001), and 0.87 (P < .0001), respectively. Measurement for the aortic arch was moderately correlated with r = 0.78 (P < .0001). Mean bias did not exceed 0.1 cm (6%). The 95% limits of agreement (LOA) were less than 0.5 cm (15%). Intra- and interobserver agreement showed a mean bias of less than 2%; the 95% LOA were less than 11%.Conclusions: Axial measurement of the diameters of the thoracic and abdominal aorta using a plain axial VIBE sequence is highly valid and reliable, making it suitable for use in epidemiologic research.

Flexible Image Evaluation: iPad versus Secondary-class Monitors for Review of MR Spinal Emergency Cases, A Comparative Study - Corrected Proof

Jonathan P. McNulty, John T. Ryan, Michael G. Evanoff, Louise A. Rainford — 2012-04-16

Rationale and Objectives: Studies have highlighted the potential of handheld viewing devices for rapid diagnosis and increased smartphone usage among physicians and radiologists is known as is the clinical applicability of hand-held devices for computed tomography (CT) spinal injury cases. Magnetic resonance (MR), however, is the accepted gold standard for spinal imaging, providing visualization of both ligament and spinal cord pathology. This study investigated the diagnostic accuracy of the iPad, the most probable alternative display device outside the radiology environment and financially viable alternative, when reviewing emergency spinal MR images, in comparison with secondary-class LCD devices in the case of the interpretation of CT and MR imaging examinations.Materials and Methods: In total 31 MR cases including both positives (n = 13) containing one of four possible presentations: spinal cord compression, cauda equine syndrome, spinal cord hemorrhage, or spinal cord edema and controls (n = 18) were reviewed. Ziltron iPad software facilitated the display of cases and the receiver operating characteristic (ROC) analysis. Thirteen American Board of Radiology board-certified radiologists reviewed all cases on both displays. Standardized viewing conditions were maintained.Results: Dorfman-Berbaum-Metz multireader-multicase (DBM MRMC) analysis was performed including random readers/random cases, fixed readers/random cases and random readers/fixed cases. No differences of statistical significance (P ≤ .05) could be found in terms of area under the curve, sensitivity and specificity between the iPad and secondary-class display.Conclusion: The iPad performed with equal diagnostic accuracy when compared with the secondary-class LCD device after DBM MRMC analysis, demonstrating the iPad as an option to aid initial review of MR spinal emergency cases.

Relationship between CT Findings and the Plasma Levels of Brain Natriuretic Peptide in 29 Patients with Acute Cardiogenic Pulmonary Edema - Corrected Proof

2012-04-16

Rationale and Objectives: Brain natriuretic peptide (BNP) is a useful biomarker for the assessment of cardiogenic pulmonary edema. This study evaluated the relationship between computed tomography (CT) findings and plasma BNP levels in patients with cardiogenic pulmonary edema.Materials and Methods: Twenty-nine consecutive outpatients with severe respiratory failure from cardiogenic edema presenting to emergency departments were enrolled. They underwent chest CT and plasma BNP levels were measured in the emergency room. CT findings were independently evaluated by two radiologists who were unaware of the patients’ clinical information.Results: The plasma BNP levels only correlated with the volume of pleural effusion in each side (right: rs = 0.519, P = .004; left: rs = 0.460, P = .012). No significant correlation was observed between the BNP levels and the findings of lung parenchyma or cardiovascular enlargement.Conclusion: Estimating the pleural effusion volume with CT may be a feasible method as well as measuring the plasma BNP level in the assessment of acute cardiogenic pulmonary edema.

Reduced Perfusion in Pulmonary Infiltrates of High-risk Hematologic Patients Is a Possible Discriminator of Pulmonary Angioinvasive Mycosis: A Pilot Volume Perfusion Computed Tomography (VPCT) Study - Corrected Proof

2012-04-13

Rationale and Objectives: The aim of this study was to assess perfusion parameters in atypical pneumonia of heavily immunocompromised hematologic patients suspected of having invasive mycosis using volume perfusion computed tomography and establish their diagnostic role.Materials and Methods: Volume perfusion computed tomographic data from 21 consecutive immunocompromised patients presenting with atypical parenchymal opacity of consolidation were analyzed with respect to the degree of perfusion of their pneumonias. All patients presented with clinical and laboratory signs of infection. Seventeen patients (10 men, seven women; mean age, 57 years; age range, 19–76 years) were found with proven (n = 9), probable (n = 2), or possible (n = 6) angioinvasive mycosis. One patient was diagnosed with bronchoinvasive aspergillosis. Four patients (all men; mean age, 71 years; age range, 67–79 years) were diagnosed with bacterial pneumonia. Volume perfusion computed tomography of the involved pulmonary areas was performed at 80 kV and 60 mAs, with 26 measurement points distributed over 65.9 seconds. Fifty milliliters of contrast material was injected at a rate of 5 mL/s, followed by a 50-mL saline chaser. Entire coverage of the pneumonic parenchymal consolidation was obtained in all patients, with the generation of parametric maps of blood flow (BF) using the maximal slope model and blood volume (BV) using Patlak analysis. The results of perfusion measurements were then analyzed and evaluated for all patients.Results: Patients with proven, probable, or possible angioinvasive pulmonary fungal infection revealed very low levels of perfusion of their parenchymal consolidations, with BFs ranging from 0.01 to 23.86 mL/100 mL tissue/min and BVs ranging from 0.88 to 10.67 mL/100 mL tissue, lower than those of the adjacent thoracic musculature and of bacterial pneumonias. Bacterial pneumonias showed all increased perfusion parameters, with BFs ranging from 30.49 to 41.65 mL/100 mL tissue/min and BVs ranging from 10.07 to 49.90 mL/100 mL tissue. The cutoff BF value for differentiation was 23.89 mL/100 mL tissue/min, and the cutoff BV value was 9.6 mL/100 mL tissue.Conclusions: Patients with angioinvasive pulmonary mycosis showed lower perfusion parameters on volume perfusion computed tomography compared to those experiencing bacterial pneumonia.

How to Write a Critically Appraised Topic (CAT) - Corrected Proof

Gelareh Sadigh, Robert Parker, Aine Marie Kelly, Paul Cronin — 2012-04-05

Medical knowledge and the volume of scientific articles published have expanded rapidly over the past 50 years. Evidence-based practice (EBP) has developed to help health practitioners get more benefit from the increasing volume of information to solve complex health problems. A format for sharing information in EBP is the critically appraised topic (CAT). A CAT is a standardized summary of research evidence organized around a clinical question, aimed at providing both a critique of the research and a statement of the clinical relevance of results. In this review, we explain the five steps involved in writing a CAT for a clinical purpose (“Ask,” “Search,” “Appraise,” “Apply,” and “Evaluate”) and introduce some of the useful electronic resources available to help in creating CATs.

Reply - Corrected Proof

Heidi Roberts — 2012-04-05

We thank Dr. Satoh and colleagues for their interest in our article and their comments about our study. Our article presents a retrospective analysis of our cohort of screen-detected lung cancers, which comes with all the limitations of a retrospective study. For example, we did not have repeat computed tomography (CT) scans in all cases to actually measure the growth rate; these were only available in 63 of the 86 cancers. We did not perform a prospective analysis of lesions detected on low-dose screening CT scans, and as such are not able to give a correct estimate on the overall number of cancers with a long doubling time; this was not the target of our study. As such, our numbers might not be comparable with the numbers from other centers, which were acquired based on different methods.

Identifying Error-making Patterns in Assessment of Mammographic BI-RADS Descriptors among Radiology Residents Using Statistical Pattern Recognition - Corrected Proof

Maciej A. Mazurowski, Huiman X. Barnhart, Jay A. Baker, Georgia D. Tourassi — 2012-03-29

Rationale and Objective: The objective of this study is to test the hypothesis that there are patterns in erroneous assessment of BI-RADS features among radiology trainees when interpreting mammographic masses and that these patterns can be captured in individualized statistical user models. Identifying these patterns could be useful in personalizing and adapting educational material to complement the individual weaknesses of each trainee during his or her mammography education.Materials and Methods: Reading data of 33 mammographic cases containing masses was used. The cases were individually described by 10 radiology residents using four BI-RADS features: mass shape, mass margin, mass density and parenchyma density. For each resident, an individual model was automatically constructed that predicts likelihood (HIGH or LOW) of erroneously assigning each BI-RADS descriptor by the resident. Error was defined as deviation of the resident's assessment from the expert assessments. We evaluated the predictive performance of the models using leave-one-out crossvalidation.Results: The user models were able to predict which assessments have higher likelihood of error. The proportion of actual errors to the number of situations in which these errors could potentially occur was significantly higher (P < .05) when user-model assigned HIGH likelihood of error than when LOW likelihood of error was assigned for three of the four BI-RADS features. Overall, the difference between the HIGH and LOW likelihood of error groups was statistically significant (P < .0001) combining all four features.Conclusion: Error making in BI-RADS descriptor assessment appears to follow patterns that can be captured with statistical pattern recognition-based user models.

Clinicopathologic Significance of High Signal Intensity on Diffusion-weighted MR Imaging in the Ureter, Urethra, Prostate and Bone of Patients with Bladder Cancer - Corrected Proof

2012-02-20

Rationale and Objectives: The aim of this study was to determine the clinicopathologic significance of high-intensity areas in the ureter, urethra, prostate, and bone incidentally found on diffusion-weighted magnetic resonance imaging (DWI) for the staging of bladder cancer.Materials and Methods: Axial and sagittal DWI and T2-weighted imaging of the pelvis were evaluated in 157 patients with bladder cancer. Two observers assessed T2-weighted imaging with DWI independently. The observers pointed out 67 areas showing abnormal high signal intensity on DWI in the ureter (n = 17), urethra (n = 8), prostate (n = 20), and bone (n = 22). Of the 67 high-intensity areas, 33 lesions were confirmed histopathologically (ureter, n = 10; urethra, n = 7; prostate, n = 16), and 22 bone lesions were diagnosed using T1-weighted imaging and follow-up computed tomography. Thus, 55 lesions were evaluable for correlation with DWI findings.Results: Of the 55 high-intensity areas, 28 (53%) were synchronous or metastatic urothelial cancer or invasion of urothelial cancer. The remaining 27 (47%) were a ureteral clot in one, a ureteral stone granuloma in one, prostatic cancer in six, granulomatous prostatitis in three, and normal red bone marrow in 16.Conclusions: DWI is useful to comprehend the extent of bladder cancer and to detect incidentally coexisting diseases. Other imaging, endoscopic, and clinical findings would be useful to reduce false positivity.

Screen-detected Lung Cancer - Corrected Proof

Koichi Kurishima, Maki Kanashiki, Hiroaki Satoh — 2012-01-24

We read with great interest the article by Dhopeshwarkar et al on screen-detected lung cancer. In their discussion, the authors stated that not a small percentage of screen-detected lung cancers on computed tomography (CT) were indolent and that there may be so-called overdiagnosis in mass screening using chest CT, which was suggested by Lindell et al . We agree with this estimation. In their article, however, Dhopeshwarkar et al reported that only 8.3% of lung cancers had doubling times > 400 days in a screening program using chest CT. This very low rate is almost the same as in the Mayo Lung Project and in a study at the Memorial Sloan-Kettering Cancer Center, evaluated using chest radiography . Also, this low rate was apparently different from those in studies by Hasegawa et al and Sone et al , evaluated using chest CT, as in the study by Dhopeshwarkar et al. We are very interested in these differences in rates. We would like to hear from the authors regarding why these differences were observed and the reason for the difference among them, although these recent studies were evaluated using chest CT.