Faculty Bibliography

Clinical data such as history, physical examination, and laboratory tests are useful in identifying patients with biliary obstruction and biliary sources of infection. However, if intervention is planned, noninvasive imaging is needed to confirm the presence, location, and extent of the disease process. Currently, the most commonly available and used noninvasive modalities are ultrasound (US), computed tomography (CT), magnetic resonance (MR), and nuclear medicine hepatobiliary scintigraphy (HIDA). US is quick, portable, readily available, and is commonly the first imaging modality used when biliary pathology is suspected. It is excellent in the detection of cholelithiasis and acute cholecystitis but is limited in detecting choledocholithiasis. CT is excellent at detecting infected postoperative fluid collections, bilomas, biliary obstruction, and biliary infection but is limited in the detection of cholelithiasis. Therefore, US may be more useful than CT for the initial screening of acute biliary disease. MR has inherent advantages over CT, as it does not use ionizing radiation, can be done without intravenous contrast, and its detection of cholelithiasis is not affected by the internal composition of the stone. Magnetic resonance cholangiopancreatography can be used to determine the cause and location of biliary obstruction but is limited in the detection of small stones and the evaluation of the biliary tract near the ampulla. HIDA is used to evaluate for cholecystitis, biliary obstruction, and bile leaks. The main limitation is its lack of anatomical detail, and it is therefore frequently performed in conjunction with other described modalities.

OBJECTIVES:To evaluate and compare the ability of DW-MRI and CT to detect sites of peritoneal dissemination in gynecologic malignancies. The reproducibility of DW-MRI and CT interpretation between radiologists was also assessed. METHODS:Single institution prospective cohort study of women with suspected advanced gynecologic cancer who underwent surgical staging from 2010 to 2013. Participants underwent both DW-MRI and contrast-enhanced CT prior to surgery. Radiologists and surgeons were blinded, respectively, to surgical and DW-MRI results. The area under the receiver operator characteristic curve (AUC) was calculated for each disease site for CT and DW-MRI and compared to surgical findings. Kappa statistics quantified interobserver agreement between both radiologists. RESULTS:Twenty seven patients were enrolled. Mean age at surgery was 59years. Ninety percent of participants had stage IIIC/IV disease. For right diaphragm disease, the AUC for DW-MRI was 0.95 compared to 0.81 for CT. For left diaphragm disease, the AUC was 0.89 for DW-MRI compared to 0.74 for CT. The AUC was similar for DW-MRI and CT for omental disease (0.79 versus 0.64); the liver surface (0.61 versus 0.67); bowel mesentery (0.73 versus 0.64); and cul de sac (0.75 versus 0.64). Interobserver agreement for DW-MRI was greater than CT for omental, Morrison's pouch, liver surface, and right diaphragm disease. CONCLUSIONS:DW-MRI detects right diaphragmatic disease found at surgery with greater accuracy than CT. For other disease sites key to surgical planning, DW-MRI is equivalent to CT. Interobserver agreement was superior for a majority of disease sites evaluated by DW-MRI compared to CT.

The past decade has seen a significant growth in diagnostic CT imaging as a direct result of the clinical value provided by CT imaging. At the same time, many new techniques and resources are now available to make CT imaging safe. This article presents the basics of CT dosimetry and their usage in clinical practices, methods to implement CT dose reduction, followed by a summary of legislation, and guidelines related to patient safety in diagnostic CT imaging. Also, CT radiation dose diagnostic reference levels from published regional and national surveys are reviewed and applied in a CT dose tracking and monitoring program.

Quality assurance has increasingly become an integral part of medicine, with tandem goals of increasing patient safety and procedural quality, improving efficiency, lowering cost, and ultimately improving patient outcomes. This article reviews quality assurance methodology, ranging from the PDSA cycle to the application of lean techniques, aimed at operational efficiency, to continually evaluate and revise the health care environment. Alignment of goals for practices, hospitals, and healthcare organizations is critical, requiring clear objectives, adequate resources, and transparent reporting. In addition, there is a significant role played by regulatory bodies and oversight organizations in determining external benchmarks of quality, practice, and individual certification and reimbursement. Finally, practical application of quality principles to practice improvement projects in abdominal imaging will be presented.

The role of stem cell therapy in the treatment of hematologic and nonhematologic conditions is ever increasing. A thorough knowledge of the applications of stem cells and transplant physiology is essential for understanding the imaging manifestations. Stem cell imaging includes molecular imaging, and diagnostic and interventional radiology. It is possible to make a diagnosis of various complications and diseases associated with stem cell transplant. This article presents a simplified overview of stem cell applications and techniques with focus on hematopoietic stem cell transplant imaging.

Benign prostatic hyperplasia (BPH) is a common condition in middle-aged and older men and negatively affects the quality of life. An ultrasound classification for BPH based on a previous pathologic classification was reported, and the types of BPH were classified according to different enlargement locations in the prostate. Afterwards, this classification was demonstrated using magnetic resonance imaging (MRI). The classification of BPH is important, as patients with different types of BPH can have different symptoms and treatment options. BPH types on MRI are as follows: type 0, an equal to or less than 25 cm3 prostate showing little or no zonal enlargements; type 1, bilateral transition zone (TZ) enlargement; type 2, retrourethral enlargement; type 3, bilateral TZ and retrourethral enlargement; type 4, pedunculated enlargement; type 5, pedunculated with bilateral TZ and/or retrourethral enlargement; type 6, subtrigonal or ectopic enlargement; type 7, other combinations of enlargements. We retrospectively evaluated MRI images of BPH patients who were histologically diagnosed and presented the different types of BPH on MRI. MRI, with its advantage of multiplanar imaging and superior soft tissue contrast resolution, can be used in BPH patients for differentiation of BPH from prostate cancer, estimation of zonal and entire prostatic volumes, determination of the stromal/glandular ratio, detection of the enlargement locations, and classification of BPH types which may be potentially helpful in choosing the optimal treatment.

OBJECTIVE:The purpose of this study was to determine the diagnostic performance of magnetic resonance imaging (MRI) in the diagnosis of acute appendicitis during pregnancy in a multiinstitutional study. STUDY DESIGN/METHODS:In this multicenter retrospective study, the cases of pregnant women who underwent MRI evaluation of abdominal or pelvic pain and who had clinical suspicion of acute appendicitis between June 1, 2009, and July 31, 2014, were reviewed. All MRI examinations with positive findings for acute appendicitis were confirmed with surgical pathologic information. Sensitivity, specificity, negative predictive values, and positive predictive values were calculated. Receiver operating characteristic curves were generated, and area under the curve analysis was performed for each participating institution. RESULTS:Of the cases that were evaluated, 9.3% (66/709) had MRI findings of acute appendicitis. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive values were 96.8%, 99.2%, 99.0%, 92.4%, and 99.7%, respectively. There was no statistically significant difference between centers that were included in the study (pair-wise probability values ranged from 0.12-0.99). CONCLUSION/CONCLUSIONS:MRI is useful and reproducible in the diagnosis of suspected acute appendicitis during pregnancy.

BACKGROUND:Using hepatocyte-specific magnetic resonance imaging (MRI) contrast agents such as gadoxetate disodium, MRI can provide functional information regarding the patency of the cystic duct similar to hepatobiliary scintigraphy in addition to anatomic images. PURPOSE/OBJECTIVE:To describe the gadoxetate disodium enhanced MR cholangiography (GDE-MRC) findings in patients with acute cholecystitis and to compare them with findings in patients without acute cholecystitis and with normal hepatobiliary scintigraphy. MATERIAL AND METHODS/METHODS:This study was HIPAA compliant and institutional review board approved. Twenty-three patients (n = 14 diagnosed with acute calculous cholecystitis based on ultrasound [US] or computed tomography [CT]; n = 9 controls with normal hepatobiliary scintigraphy) were prospectively enrolled. All patients underwent GDE-MRC within 2 days of the US, CT, or hepatobiliary scintigraphy. GDE-MRC included axial gradient echo T1-weighted images before and 3, 10, 20, 30, and 60 min after injection of 10 mL of gadoxetate disodium. If excretion of contrast into the gallbladder was not noted at 60 min, intravenous morphine was administered (0.04 mg/kg) and images were acquired 30 min later. RESULTS:In all nine controls, gadoxetate disodium was excreted into the gallbladder within 60 min (7/9 in <30 min). Twelve out of 14 patients with acute cholecystitis completed the study. Six out of 12 (50%) patients demonstrated contrast in their gallbladder within 1 h of administration similar to the control group (2/6 in <30 min). In the remaining 6/12 patients, contrast was not present in the gallbladder within 1 h from injection. Following morphine augmentation, contrast was subsequently noted in the gallbladder in 2/6 patients. CONCLUSION/CONCLUSIONS:GDE-MRC can assess the patency of the cystic duct. Delayed (>60 min) or lack of filling of the gallbladder during GDE-MRC supports the diagnosis of acute cholecystitis. However, filling of the gallbladder with contrast in <60 min does not exclude the diagnosis of acute calculous cholecystitis.

PURPOSE/OBJECTIVE:To evaluate the performance and interobserver agreement of qualitative dynamic contrast material enhanced magnetic resonance (MR) imaging curve analysis as described in the Prostate Imaging Reporting and Data System (PI-RADS) for the differentiation of prostate cancer (PCa) from healthy prostatic tissue in the peripheral zone (PZ). MATERIALS AND METHODS/METHODS:This Health Insurance Portability and Accountability Act-compliant institutional review board-approved retrospective analysis included 120 consecutive pretreatment dynamic contrast-enhanced (DCE) MR imaging PCa examinations. Regions of interest (ROIs) were placed in 251 spots, including 95 (37.8%) in healthy PZ tissue and 156 (62.2%) in PCa, by using detailed histologic-multiparametric MR correlation review. Three radiologists reviewed the DCE time curves and assessed qualitative curve types as described in PI-RADS: type 1 (progressive), type 2 (plateau), or type 3 (washout). Receiver operating characteristic curve analysis was used to assess accuracy in differentiating PCa from healthy tissue on the basis of curve type, and κ was calculated to assess interobserver agreement. RESULTS:Receiver operating characteristic curves were similar for all observers, but mean areas under the receiver operating characteristic curve were poor (0.58 ± 0.04 [standard deviation] to 0.63 ± 0.04). No differences in accuracy were seen for varying DCE time resolution and imaging length. Observer agreement in assessment of type 3 versus types 1 or 2 curves was substantial (0.66 < κ < 0.79), better for PCa ROIs than for healthy-tissue ROIs. The agreement between type 1 and type 2 curves was moderate to substantial (0.49 < κ < 0.78). CONCLUSION/CONCLUSIONS:Qualitative DCE MR imaging time-curve-type analysis performs poorly for differentiation of PCa from healthy prostatic tissue. Interobserver agreement is excellent in assessment of type 3 curves but only moderate for type 1 and 2 curves.

OBJECTIVE:To predict biliary stent occlusion on computed tomography (CT) from the loss of pneumobilia. METHODS:A total of 66 patients with common bile duct stents with pneumobilia after initial stent placement had a follow-up CT and diagnostic endoscopic retrograde cholangiopancreatography (ERCP). Two readers evaluated all CT exams for pneumobilia. Resolution or decrease of pneumobilia on CT was compared with ERCP findings. RESULTS:Sensitivity and specificity was 60-64% and 95% with a positive predictive value of 97% and a negative predictive value of 49-51%. CONCLUSION/CONCLUSIONS:Resolution or reduction of pneumobilia after stent placement is specific (95%) and is moderately accurate (70-73%) for predicting biliary stent occlusion.