Faculty Bibliography

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.

OBJECTIVE: To determine whether patient-specific 3D printed renal tumor models change pre-operative planning decisions made by urological surgeons in preparation for complex renal mass surgical procedures. MATERIALS AND METHODS: From our ongoing IRB approved study on renal neoplasms, ten renal mass cases were retrospectively selected based on Nephrometry Score greater than 5 (range 6-10). A 3D post-contrast fat-suppressed gradient-echo T1-weighted sequence was used to generate 3D printed models. The cases were evaluated by three experienced urologic oncology surgeons in a randomized fashion using (1) imaging data on PACS alone and (2) 3D printed model in addition to the imaging data. A questionnaire regarding surgical approach and planning was administered. The presumed pre-operative approaches with and without the model were compared. Any change between the presumed approaches and the actual surgical intervention was recorded. RESULTS: There was a change in planned approach with the 3D printed model for all ten cases with the largest impact seen regarding decisions on transperitoneal or retroperitoneal approach and clamping, with changes seen in 30%-50% of cases. Mean parenchymal volume loss for the operated kidney was 21.4%. Volume losses >20% were associated with increased ischemia times and surgeons tended to report a different approach with the use of the 3D model compared to that with imaging alone in these cases. The 3D printed models helped increase confidence regarding the chosen operative procedure in all cases. CONCLUSIONS: Pre-operative physical 3D models created from MRI data may influence surgical planning for complex kidney cancer.

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.

PURPOSE: The purpose of the study is to perform a meta-analysis of studies investigating the diagnostic performance of apparent diffusion coefficient (ADC) values in separating high-risk from low-risk prostate cancer (PCa). METHODS: MEDLINE and EMBASE databases were searched in December 2015 for studies reporting diagnostic performance of ADC values for discriminating high-risk from low-risk PCa and providing sufficient data to construct 2 x 2 contingency tables. Diagnostic performance was quantitatively pooled using a bivariate random-effects model including subgroup analysis and assessment of study heterogeneity and methodological quality. RESULTS: 13 studies were included, providing 1107 tumor foci in 705 patients. Heterogeneity among studies was moderate (tau2 = 0.222). Overall sensitivity was 76.9% (95% CI 68.6-83.6%); overall specificity was 77.0% (95% CI 69.9-82.8%); and summary AUC was 0.67. Inverse correlation between sensitivity and specificity (rho = -0.58) indicated interstudy heterogeneity was partly due to variation in threshold for test positivity. Primary biases were readers' knowledge of Gleason score during ADC measurement, lack of prespecified ADC thresholds, and lack of prostatectomy as reference in some studies. Higher sensitivity was seen in studies published within the past 2 years and studies not using b value of at least 2000; higher specificity was associated with involvement of one, rather than two, readers measuring ADC. Field strength, coil selection, and advanced diffusion metrics did not significantly impact diagnostic performance. CONCLUSION: ADC values show moderate accuracy in separating high-risk from low-risk PCa, although important biases may overestimate performance and unexplained sources of heterogeneity likely exist. Further studies using a standardized methodology and addressing identified weaknesses may help guide the use of ADC values for clinical decision-making.

Incidental and secondary findings have become an important by-product of diagnostic testing, and their ramifications affect clinical care, research, and policy. Given parallels in the reporting and management of such findings on diagnostic imaging, radiologists may draw from ongoing discussions in medical genetics to rethink more patient-centered approaches to analogous clinical, ethical, and medicolegal dilemmas. Low-risk incidental findings in particular may be drivers of unnecessary testing, invasive procedures, and overtreatment, with associated financial, psychological, and clinical consequences. As radiologists act in patients' best interests by strengthening standardized guidelines on how each finding merits further diagnostic testing or treatment, perhaps the greatest challenge for producing such guidelines is for low-risk incidental findings, for which adverse consequences are unlikely but associated with substantial uncertainty because of the lack of strong evidence on which to base the recommendations. More uniform recommendations for managing low-risk radiologic incidental findings should therefore aim to provide reasonable options that apply across a spectrum of patient preferences. These will require evaluation through research and will ultimately influence the quality of care. Specific areas for exploration may include (1) better gauging of patient attitudes and preferences regarding low-risk incidental findings, (2) using patient preferences to inform more uniform recommendations for low-risk findings that apply across a spectrum of preferences and help guide shared decision making, and (3) when patients endorse a strong preference not to discover low-risk incidental findings, how it might be possible for professional standards to curtail their generation in specific circumstances.

OBJECTIVE: The purpose of this article is to compare the effectiveness of a treatment algorithm for small renal tumors incorporating the nephrometry score, a renal tumor anatomy scoring system developed by urologists, with the current standard of uniformly recommended partial nephrectomy in patients with mild-to-moderate chronic kidney disease (CKD). MATERIALS AND METHODS: We developed a state-transition microsimulation model to project life expectancy (LE) in hypothetic patients with baseline mild or moderate CKD undergoing treatment of small renal masses. Our model incorporated the nephrometry score, which is predictive of postsurgical renal function loss. The two tested strategies were uniform treatment with partial nephrectomy and selective treatment based on nephrometry score and CKD stage, including percutaneous ablation for CKD stages 2 or 3a and intermediate-to-high nephrometry score or stage 3b CKD and any nephrometry score; otherwise, partial nephrectomy was assumed for other CKD stages and nephrometry scores. The model accounted for benign and malignant lesions, renal function decline, recurrence, and metastatic disease rates specific to each treatment, mortality by CKD stage, and comorbidities. Sensitivity analysis tested the stability of results when varying key parameters. RESULTS: Selective treatment with partial nephrectomy resulted in an average LE benefit of 0.48 year (95% interpercentile range, 0.42-0.54 year) in 65-year-old men and 0.37 year (95% interpercentile range, 0.30-0.43 year) in 65-year-old women relative to nondiscriminatory surgery, due to worsening CKD and cardiovascular mortality associated with partial nephrectomy. Model results were most sensitive to the rate of renal function decline and CKD-related mortality. CONCLUSION: Nephron-sparing treatment selection for small renal masses based on nephrometry score may improve LE in patients with mild or moderate CKD.

Health outcomes research is essential to align radiology with current standards of high-value patient care, through the assessment of end results of diagnostic tests, interventions, or policy on patient health. To bridge studies of diagnostic test accuracy and health outcomes research, key considerations include: (1) how to determine when a diagnostic test merits evaluation of impact on outcomes, (2) when study of intermediate/surrogate outcomes can be useful, (3) how to consider the possible harms as well as potential benefits of a test, and (4) how to integrate evidence of an imaging test's efficacy/effectiveness with clinical data to assess outcomes. Due to challenges in conducting studies of long-term outcomes consequent to imaging use, intermediate health outcomes may capture a test's impact on successful diagnosis and therapy, and can provide readily measurable, incremental insights into the role of imaging in health-care delivery and efficiency. In an era marked by recognition of quality and value of care, outcomes research will provide essential evidence to inform radiologists' guidance of imaging use toward improved patient care, creation of clinical guidelines, and policy decisions.

Acute pelvic pain in premenopausal women frequently poses a diagnostic dilemma. These patients may exhibit nonspecific signs and symptoms such as nausea, vomiting and leukocytosis. The cause of pelvic pain includes a myriad of diagnostic possibilities such as obstetric, gynecologic, urologic, gastrointestinal, and vascular etiologies. The choice of the imaging modality is usually determined by a suspected clinical differential diagnosis. Thus the patient should undergo careful evaluation and the suspected differential diagnosis should be narrowed before an optimal imaging modality is chosen. Transvaginal and transabdominal pelvic sonography is the modality of choice, to assess for pelvic pain, when an obstetric or gynecologic etiology is suspected and computed tomography is often more useful when gastrointestinal or genitourinary pathology is thought to be more likely. Magnetic resonance imaging, when available in the acute setting, is favored over computed tomography for assessing pregnant patients for nongynecologic etiologies owing to its lack of ionizing radiation.The American College of Radiology Appropriateness Criteria(R) are evidence-based guidelines for specific clinical conditions that are reviewed every three years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

AIMS: Selective vascular endothelial growth factor receptor (VEGFR) inhibitors have the potential for greater potency and less off-target toxicity compared with multikinase tyrosine kinase inhibitors in the treatment of metastatic renal cell carcinoma. We carried out a meta-analysis to determine quantitatively the differences in comparative efficacy and tolerability between these newer, selective agents and the multikinase inhibitors. MATERIALS AND METHODS: We searched four electronic databases for published randomised controlled trials comparing selective VEGFR inhibitors with multikinase tyrosine kinase inhibitors for metastatic renal cell carcinoma and carried out a meta-analysis. Outcomes of interest were progression-free survival, objective response rate (ORR), overall survival, discontinuation of treatment due to adverse events (DAE) and occurrence of specific toxicities. RESULTS: Four trials involving the selective VEGFR inhibitors axitinib, tivozanib and dovitinib were analysed, all using sorafenib as the comparator. There was a 22% reduction in risk of disease progression with selective VEGFR inhibitors (relative risk 0.78; 95% confidence interval 0.69-0.87) compared with sorafenib, the tyrosine kinase inhibitor in all trials, and similar whether the agents were first-line or subsequent therapy. ORR was improved with selective VEGFR inhibitors, with 91% increased odds over sorafenib (odds ratio 1.91; 95% confidence interval 1.35-2.69). Overall survival was similar between groups (relative risk 1.03; 95% confidence interval 0.88-1.21) and DAE differed only in sensitivity analysis with exclusion of dovitinib (odds ratio 0.62; 95% confidence interval 0.41-0.94). Frequencies of the most common toxicities were overall similar, but differences included more frequent grade 3 or 4 fatigue and less frequent palmar-plantar erythrodysesthesia with selective VEGFR therapy. CONCLUSION: Although selective VEGFR inhibitors are associated with similar overall survival as multikinase inhibitor sorafenib, they show significant improvement in progression-free survival, regardless of first-line or later use, and ORR compared with sorafenib. Tolerability due to toxicities is similar.