Faculty Bibliography

PURPOSE/OBJECTIVE:The aim of this study was to evaluate the utility of added DWI sequences as an adjunct to traditional MR imaging in the evaluation of abnormal placentation in patients with suspicion for placenta accreta spectrum abnormality or morbidly adherent placenta (MAP). MATERIALS AND METHODS/METHODS:The study was approved by local ethics committee. The subjects included pregnant women with prenatal MRI performed between July 2013 to July 2015. All imaging was performed on a Philips 1.5T MR scanner using pelvic phased-array coil. Only T2-weighted and diffusion-weighted imaging (DWI) series were compiled for review. Two randomized imaging sets were created: set 1 included T2-weighted series only (T2W); set 2 included T2W with DWI series together (T2W + DWI). Three radiologists, blinded to history and pathology, reviewed the imaging, with 2 weeks of time between the two image sets. Sensitivity, specificity, and overall accuracy for MAP were calculated and compared between T2W only and T2W + DWI reads. Associations between imaging findings and invasion on pathology were tested using the Chi-squared test. Confidence scores, inter-reader agreement, and systematic differences were documented. RESULTS:A total of 17 pregnant women were included in the study. 8 cases were pathologically diagnosed with MAP. There were no significant differences in the diagnostic accuracy between T2W and T2W + DWI in the diagnosis of MAP in terms of overall accuracy (62.7% for T2W vs. 68.6% for T2W + DWI, p = 0.68), sensitivity (70.8% for T2W vs. 95.8% for T2W + DWI, p = 0.12), and specificity (55.6% for T2W vs. 44.4% for T2W + DWI, p = 0.49). There was no significant difference in the diagnostic confidence between the review of T2W images alone and the T2W + DWI review (mean 7.3 ± 1.8 for T2W vs. 7.5 ± 1.8 for T2W + DWI, p = 0.37). CONCLUSION/CONCLUSIONS:With the current imaging technique, addition of DWI sequence to the traditional T2W images cannot be shown to significantly increase the accuracy or reader confidence for diagnosis of placenta accreta spectrum abnormality. However, DWI does improve identification of abnormalities in the placental-myometrial interface.

Provided methodologic training, more imagers can contribute to the evidence basis on improved health outcomes and value in diagnostic imaging. The Value of Imaging Through Comparative Effectiveness Research Program was developed to provide hands-on, practical training in five core areas for comparative effectiveness and big biomedical data research: decision analysis, cost-effectiveness analysis, evidence synthesis, big data principles, and applications of big data analytics. The program's mixed format consists of web-based modules for asynchronous learning as well as in-person sessions for practical skills and group discussion. Seven diagnostic radiology subspecialties and cardiology are represented in the first group of program participants, showing the collective potential for greater depth of comparative effectiveness research in the imaging community.

OBJECTIVE: The purpose of this study is to assess differences in patient distress, risk perception, and treatment preferences for incidental renal findings with descriptive versus combined descriptive and numeric graphical risk information. MATERIALS AND METHODS: A randomized survey study was conducted for adult patients about to undergo outpatient imaging studies at a large urban academic institution. Two survey arms contained either descriptive or a combination of descriptive and numeric graphical risk information about three hypothetical incidental renal findings at CT: 2-cm (low risk) and 5-cm (high risk) renal tumors and a 2-cm (low risk) renal artery aneurysm. The main outcomes were patient distress, perceived risk (qualitative and quantitative), treatment preference, and valuation of lesion discovery. RESULTS: Of 374 patients, 299 participated (79.9% response rate). With inclusion of numeric and graphical, rather than only descriptive, risk information about disease progression for a 2-cm renal tumor, patients reported less worry (3.56 vs 4.12 on a 5-point scale; p < 0.001) and favored surgical consultation less often (29.3% vs 46.9%; p = 0.003). The proportion choosing surgical consultation for the 2-cm renal tumor decreased to a similar level as for the renal artery aneurysm with numeric risk information (29.3% [95% CI, 21.7-36.8%] and 27.9% [95% CI, 20.5-35.3%], respectively). Patients overestimated the absolute risk of adverse events regardless of risk information type, but significantly more so when given descriptive information only, and valued the discovery of lesions regardless of risk information type (range, 4.41-4.81 on a 5-point scale). CONCLUSION: Numeric graphical risk communication for patients about incidental renal lesions may facilitate accurate risk comprehension and support patients in informed decision making.

There has been much interest in the identification of a successful ovarian cancer screening test, in particular, one that can detect ovarian cancer at an early stage and improve survival. We reviewed the currently available data from randomized and observational trials that examine the role of imaging for ovarian cancer screening in average-risk and high-risk women. We found insufficient evidence to recommend ovarian cancer screening, when considering the imaging modality (pelvic ultrasound) and population (average-risk postmenopausal women) for which there is the greatest available published evidence; randomized controlled trials have not demonstrated a mortality benefit in this setting. Screening high-risk women using pelvic ultrasound may be appropriate in some clinical situations; however, related data are limited because large, randomized trials have not been performed in this setting. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Purpose To investigate whether assessment of bone strength with quantitative computed tomography (CT) in combination with dual-energy x-ray absorptiometry (DXA) is cost-effective as a screening tool for osteoporosis in postmenopausal women. Materials and Methods A state-transition microsimulation model of osteoporosis for postmenopausal women aged 55 years or older was developed with a lifetime horizon and U.S. societal perspective. All model inputs were derived from published literature. Three strategies were compared: no screening, DXA with T score-dependent rescreening intervals, and a combination of DXA and quantitative CT with different intervals (3, 5, and 10 years) at different screening initiation ages (55-65 years). Oral bisphosphonate therapy was started if DXA hip T scores were less than or equal to -2.5, 10-year risk for hip fracture was greater than 3% (World Health Organization Fracture Risk Assessment Tool score, or FRAX), 10-year risk for major osteoporotic fracture was greater than 20% (FRAX), quantitative CT femur bone strength was less than 3000 N, or occurrence of first fracture (eg, hip, vertebral body, wrist). Outcome measures were incremental cost-effectiveness ratios (ICERs) in 2015 U.S. dollars per quality-adjusted life year (QALY) gained and number of fragility fractures. Probabilistic sensitivity analysis was also performed. Results The most cost-effective strategy was combined DXA and quantitative CT screening starting at age 55 with quantitative CT screening every 5 years (ICER, $2000 per QALY). With this strategy, 12.8% of postmenopausal women sustained hip fractures in their remaining life (no screening, 18.7%; DXA screening, 15.8%). The corresponding percentages of vertebral fractures for DXA and quantitative CT with a 5-year interval, was 7.5%; no screening, 11.1%; DXA screening, 9%; for wrist fractures, 14%, 17.8%, and 16.4%, respectively; for other fractures, 22.6%, 30.8%, and 27.3%, respectively. In probabilistic sensitivity analysis, DXA and quantitative CT at age 55 years with quantitative CT screening every 5 years was the best strategy in more than 90% of all 1000 simulations (for thresholds of $50 000 per QALY and $100 000 per QALY). Conclusion Combined assessment of bone strength and bone mineral density is a cost-effective strategy for osteoporosis screening in postmenopausal women and has the potential to prevent a substantial number of fragility fractures. (c) RSNA, 2017 Online supplemental material is available for this article.

Purpose To analyze the cost effectiveness of the American Society for Gastrointestinal Endoscopy (ASGE) risk stratification guidelines versus magnetic resonance (MR) cholangiopancreatography-based treatment of patients with possible choledocholithiasis. Materials and Methods A decision-analytic model was constructed to compare cost and effectiveness of three diagnostic strategies for gallstone disease with possible choledocholithiasis: noncontrast MR cholangiopancreatography, contrast material-enhanced MR imaging/MR cholangiopancreatography, and ASGE risk stratification guidelines for diagnostic evaluation recommending endoscopy (high risk), MR cholangiopancreatography (intermediate risk), or no test (low risk). Analysis was performed from a U.S. health system perspective over 1-year and lifetime horizons. The model accounted for benign and malignant causes of biliary obstruction and procedural complications. Cost information was based on Medicare reimbursements. Sensitivity analysis assessed the impact of parameter variability on model results. Results Noncontrast MR cholangiopancreatography was most cost-effective in 45-55-year-old patients (less than $100 000 per quality-adjusted life-year [QALY] gained), while contrast-enhanced MR imaging was favored in younger adults. Risk-stratified testing was less costly than MR cholangiopancreatography, with long-term savings of $1870 and $2068 versus noncontrast and contrast-enhanced MR cholangiopancreatography, respectively, but was also less effective (-0.1814, -0.1831 QALY, respectively). The lifetime incremental cost per QALY for noncontrast MR cholangiopancreatography was $10 311. Contrast-enhanced MR imaging was favored with pretest probabilities of biliary stricture or malignancy 0%-73% for patients aged 20-44 years. For patients older than 55 years, ASGE guidelines maximized QALYs at the lowest cost. Conclusion Although adults older than 55 years of age are optimally evaluated by using ASGE guidelines, younger patients suspected of having acute biliary obstruction likely benefit from MR cholangiopancreatography rather than risk-stratified diagnostic imaging because of improved detection of choledocholithiasis and alternative causes of biliary obstruction. (c) RSNA, 2017 Online supplemental material is available for this article.

PURPOSE: To compare the performance of non-contrast MRI with half-Fourier acquisition single-shot turbo spin echo (HASTE) vs. contrast-enhanced MRI/3D-MRCP for assessment of suspected choledocholithiasis in hospitalized patients. METHODS AND MATERIALS: 123 contrast-enhanced abdominal MRI/MRCP scans in the hospital setting for possible choledocholithiasis were retrospectively evaluated. Endoscopic retrograde cholangiopancreatography, intraoperative cholangiogram or documented clinical resolution served as the reference standard. Readers first evaluated the biliary tree using coronal and axial HASTE and other non-contrast sequences, and later reviewed the entire exam with post-contrast sequences and 3D-MRCP. Test performance for the image sets was compared for choledocholithiasis, acute hepatitis, cholangitis, and acute cholecystitis. Reader agreement, MRCP image quality, and confidence levels were also assessed. Clinical predictors of age and fever were tested for association with perceived need for contrast in biliary assessment. RESULTS: There were 27 cases of choledocholithiasis, 31 cases of acute hepatitis, 37 cases of acute cholecystitis, and 3 clinically diagnosed cases of acute cholangitis. Both the abbreviated and full contrast-enhanced/MRCP image sets resulted in high accuracy for choledocholithiasis (91.1-94.3% vs. 91.9-92.7%). There was no difference in sensitivity or specificity for either reader for any diagnosis between image sets (p > 0.40). 1 reader showed improved confidence (p < 0.001) with inclusion of MRCP and contrast-enhanced images, but neither confidence nor MRCP quality scores were associated with diagnostic accuracy. Patient age and fever did not predict the need for contrast-enhanced images. CONCLUSION: In hospitalized patients with suspected choledocholithiasis, performance of non-contrast abdominal MRI with HASTE is similar to contrast-enhanced MRI with 3D-MRCP, offering potential for decreased scanning time and improved patient tolerability.

BACKGROUND: Encapsulated non-invasive follicular variant papillary thyroid cancer (ENIFVPTC) has recently been re-termed noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). This designation specifically omits the word "cancer" to encourage conservative management since patients with NIFTP tumors have been shown to derive no benefit from completion thyroidectomy or adjuvant radioactive iodine (RAI) therapy. METHODS: IRB approved retrospective study of consecutive cases of tumors from 2007 to 2015 that met pathologic criteria for NIFTP. The Conservative Management (CM) group included patients managed with lobectomy alone or appropriately indicated total thyroidectomy. Those included in the Aggressive Management (AM) group received either completion thyroidectomy or radioactive iodine or both. RESULTS: From 100 consecutive cases of ENIFVPTC reviewed, 40 NIFTP were included for the final analysis. Of these, 10 (27%) patients treated with initial lobectomy received completion thyroidectomy and 6 of 37 (16%) also received post-surgical adjuvant RAI. The mean per-patient cost of care in the AM group was $17629+/-2865 nearly twice the $8637+/- 309 costs in the CM group, and was largely driven by the cost of completion thyroidectomy and RAI. CONCLUSIONS: The term NIFTP has been recently promulgated to identify a type of thyroid neoplasm, formerly identified as a low-grade cancer, for which initial surgery represents adequate treatment. We believe that since the new NIFTP nomenclature intentionally omits the word "cancer" the clinical indolence of these tumors will be better appreciated, and cost savings will result from a more conservative and appropriate clinical management.