Zarine K. Shah

New cross-sectional imaging feature definitions and standardized reporting recommendations for chronic pancreatitis will allow a more standardized approach to diagnosis and assessment of disease severity for clinical trials. Chronic pancreatitis is an inflammatory condition of the pancreas with clinical manifestations ranging from abdominal pain, acute pancreatitis, exocrine and/or endocrine dysfunction, and pancreatic cancer. There is a need for longitudinal studies in well-phenotyped patients to ascertain the utility of cross-sectional imaging findings of chronic pancreatitis for diagnosis and assessment of disease severity. CT and MR cholangiopancreatography are the most common cross-sectional imaging studies performed for the evaluation of chronic pancreatitis. Currently, there are no universal reporting standards for chronic pancreatitis. Several features of chronic pancreatitis are applied clinically, such as calcifications, parenchymal T1 signal changes, focal or diffuse gland atrophy, or irregular contour of the gland. Such findings have not been incorporated into standardized diagnostic criteria. There is also lack of consensus on quantification of disease severity in chronic pancreatitis, other than by using ductal ...

Purpose To apply k‐means clustering of two pharmacokinetic parameters derived from 3T dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) to predict the chemotherapeutic response in bladder cancer at the mid‐cycle timepoint. Materials and Methods With the predetermined number of three clusters, k‐means clustering was performed on nondimensionalized Amp and k_ep estimates of each bladder tumor. Three cluster volume fractions (VFs) were calculated for each tumor at baseline and mid‐cycle. The changes of three cluster VFs from baseline to mid‐cycle were correlated with the tumor's chemotherapeutic response. Receiver‐operating‐characteristics curve analysis was used to evaluate the performance of each cluster VF change as a biomarker of chemotherapeutic response in bladder cancer. Results The k‐means clustering partitioned each bladder tumor into cluster 1 (low k_ep and low Amp), cluster 2 (low k_ep and high Amp), cluster 3 (high k_ep and low Amp). The changes of all three cluster VFs were found to be associated with bladder tumor response to chemotherapy. The VF change of cluster 2 presented with the highest area‐under‐the‐curve value (0.96) and the highest sensitivity/specificity/accuracy (96%/100%/97%) with a selected cutoff value. Conclusion The k‐means clustering of the two DCE‐MRI pharmacokinetic parameters can characterize the complex microcirculatory changes within a bladder tumor to enable early prediction of the tumor's chemotherapeutic response. J. Magn. Reson. Imaging 2015;41:1374–1382.

Objectives The objective of this study was to assess the capability of T2-weighted magnetic resonance imaging (T2W-MRI) and the additional diagnostic value of dynamic contrast-enhanced MRI (DCE-MRI) using multitransmit 3 T in the localization of bladder cancer. Materials and Methods This prospective study was approved by the local institutional review board. Thirty-six patients were included in the study and provided informed consent. Magnetic resonance imaging scans were performed with T2W-MRI and DCE-MRI on a 3-T multitransmit system. Two observers (with 12 and 25 years of experience) independently interpreted T2W-MRI before DCE-MRI data (maps of pharmacokinetic parameters) to localize bladder tumors. The pathological examination of cystectomy bladder specimens was used as a reference criteria standard. The McNemar test was performed to evaluate the differences in sensitivity, specificity, and accuracy. Scores of κ were calculated to assess interobserver agreement. Results The sensitivity, specificity, and accuracy of the localization with T2W-MRI alone were 81% (29/36), 63% (5/8), and 77% (34/44) for observer 1 and 72% (26/36), 63% (5/8), and 70% (31/44) for observer 2. With additional DCE-MRI available, these values were 92% (33/36), 75% (6/8), and 89% (39/44) for observer 1 and 92% (33/36), 63% (5/8), and 86% (38/44) for observer 2. Dynamic contrast-enhanced MRI significantly (P < 0.01) improved the sensitivity and accuracy for observer 2. For the 23 patients treated with chemotherapy, DCE-MRI also significantly (P < 0.02) improved the sensitivity and accuracy of bladder cancer localization with T2W-MRI alone for observer 2. Scores of κ were 0.63 for T2W-MRI alone and 0.78 for additional DCE-MRI. Of 7 subcentimeter malignant tumors, 4 (57%) were identified on T2W images and 6 (86%) were identified on DCE maps. Of 11 malignant tumors within the bladder wall thickening, 6 (55%) were found on T2W images and 10 (91%) were found on DCE maps. Conclusions Compared with conventional T2W-MRI alone, the addition of DCE-MRI improved interobserver agreement as well as the localization of small malignant tumors and those within bladder wall thickening.

The use of an endorectal coil is an essential part of the prostate 1.5T MR imaging protocol. However endorectal coil MRI is limited by availability, cost, patient discomfort, motion, and claustrophobia. MRI at 3T has a theoretical advantage of twice as much signal-to-noise as MRI at 1.5T. This study is performed to compare the prostate imaging quality at 3T with a surface coil to that of endorectal 1.5T imaging.

Purpose: To evaluate the capability of amide proton transfer (APT) MR imaging for detection of prostate cancer that typically shows a higher tumor cell proliferation rate and cellular density leading to an MRI‐detectable overall elevated mobile protein level in higher grade tumors.Materials and Methods: Twelve patients with biopsy‐proven prostate cancer were imaged on a 3 Tesla MR imaging system before prostatectomy. APT‐MR images were acquired by means of a single‐slice single‐shot turbo spin echo sequence with a saturation prepulse preparation using 33 different frequency offsets (−8 to 8 ppm, interval 0.5 ppm). For quantification we used the APT ratio (APTR) based on the asymmetry of the magnetization transfer ratio at 3.5 ppm in respect to the water signal. Tumor and peripheral zone benign regions of interest (ROIs) were delineated based on whole mount pathology slides after prostatectomy.Results: APTR in prostate cancer ROIs was 5.8% ± 3.2%, significantly higher than that in the peripheral zone benign regions (0.3% ± 3.2%, P = 0.002).Conclusion: APT‐MR imaging is feasible in prostate cancer detection and has the potential to discriminate between cancer and noncancer tissues. J. Magn. Reson. Imaging 2011;33:647–654.

Predictive value of multi-detector computed tomography for accurate diagnosis of serous cystadenoma: Radiologic-pathologic correlation

The purpose of the study was to compare the quality of stomach and small bowel marking/labeling using 1,350 ml of low-density barium alone (VoLumen) with 900 ml of low-density barium and 450 ml of water for 16-MDCT scans of the abdomen and pelvis and assess cost benefits with the two protocols. In this IRB approved study, 80 consecutive patients scheduled for routine CECT (contrast-enhanced CT) of the abdomen-pelvis were studied. Patients were randomized into two groups and were administered either 1,350 ml of VoLumen (two bottles at 20-min intervals, one half bottle at 50 min and the last half on the table) or 900 ml of VoLumen (two bottles at 20-min intervals and 450 ml water on the table). Portal venous phase scanning (detector collimation = 0.625 mm, speed = 18.75 mm, thickness = 5 mm) was subsequently performed. Images were reconstructed in axial and coronal plane at the CT console. Two blinded readers used a pre-designed template to assess distension and wall characteristics of the stomach and small bowel on a 5-point scale. Median scores with the two protocols were compared using the Wilcoxon rank sum test. The stomach and small bowel labeling was rated fair to optimal in all patients and did not differ significantly in the two protocols. The mean scores for distension of the small bowel and stomach were comparable. Inter-observer agreement for bowel labeling was found to be excellent (k 0.81). With the use of coronal images there was increased reader confidence in tracing the small bowel with both protocols. Acceptance for two bottles of VoLumen and water was greater among patients as compared to three bottles of VoLumen. Use of two bottles of VoLumen and water combination cost less than three bottles of VoLumen. Stomach and small bowel labeling with administration of 900 ml of VoLumen followed by 450 ml of water is cost effective and compares well to 1,350 ml of VoLumen alone.