Faculty Bibliography

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.

Purpose To determine the performance of dynamic contrast material-enhanced magnetic resonance (MR) imaging in the diagnosis of small (/= .122). At pairwise meta-regression analysis with either study origin from Asia or performance of hepatobiliary phase imaging, only gadoxetate disodium contrast agent showed significant independent association with higher sensitivity (P = .002-.007). Conclusion Results of this meta-analysis suggest that dynamic contrast-enhanced MR imaging has moderate sensitivity and excellent specificity in the detection of HCC up to 2 cm. Gadoxetate disodium contrast agent showed the strongest association with increased sensitivity. (c) RSNA, 2015 Online supplemental material is available for this article.

OBJECTIVE: The purpose of this study was to retrospectively investigate associations between baseline CT findings in suspected acute appendicitis and subsequent hospital resource utilization. MATERIALS AND METHODS: One hundred thirty-eight patients (76 male and 62 female patients; mean [+/- SD] age, 40 +/- 21 years) who were admitted for suspected acute appendicitis and underwent baseline CT were included. A single radiologist reviewed CT examinations for appendiceal-related findings. Linear and logistic regressions were performed to identify independent predictors of payer and hospital resource utilization. Combined performance of identified independent factors for predicting outcomes was determined. RESULTS: Greater age, lower Charlson comorbidity index (CCI), lesser appendiceal wall thickness, absence of loculated fluid collection, and absence of periappendiceal fluid were significant independent predictors of inpatient surgery (joint sensitivity, 92.7%; specificity, 65.8%). Smaller appendiceal diameter, absence of periappendiceal fluid, and laparoscopic surgery were significant independent predictors of same-day discharge (joint sensitivity, 79.1%; specificity, 64.2%). Greater CCI, greater wall thickness, and presence of periappendiceal fluid were significant independent predictors of repeat abdominopelvic CT (joint sensitivity, 82.5%; specificity, 68.1%). Presence of an appendicolith was the only significant predictor of repeat emergency department visit within 30 days (sensitivity, 61.2%; specificity, 68.8%) and the only significant predictor of repeat inpatient admission within 30 days (sensitivity, 63.6%; specificity, 68.5%). Greater appendiceal diameter and presence of free air were significant predictors of inpatient costs, and predicted costs were as follows: $8047 + ($745 x appendiceal diameter) if free air was absent; and $-39,261 + ($4426 x appendiceal diameter) if free air was present. However, costs were poorly predicted when greater than $45,000. Sex, WBC count, and payer category were not independent predictors, relative to CT findings, of any outcome. CONCLUSION: Admission CT findings serve as independent predictors of hospital resource utilization in suspected acute appendicitis.

OBJECTIVE: The objective of our study was to perform a systematic review and meta-analysis of the test performance of DWI in the characterization of renal masses. MATERIALS AND METHODS: We performed searches of three electronic databases for studies on renal mass characterization using DWI. Methodologic quality was assessed for each study. We quantitatively analyzed test performance for three clinical problems: first, benign versus malignant lesions; second, clear cell renal cell carcinoma (RCC) versus other malignancies; and, third, high-versus low-grade clear cell RCCs. We summarized performance as a single pair of sensitivity and specificity values or a summary ROC curve. RESULTS: The studies in the literature were limited in both quantity and quality. For classification of benign versus malignant lesions, four studies with 279 lesions yielded a single summary estimate of 86% sensitivity and 78% specificity. For differentiation of clear cell RCC from other malignancies, five studies showed marked heterogeneity not conducive to meta-analysis. For differentiation of high-from low-grade clear cell RCCs, three studies with 110 lesions showed a threshold effect appropriate for summary ROC construction: The AUC was 0.83. CONCLUSION: Evidence suggests moderate accuracy of DWI for the prediction of malignancy and high-grade clear cell cancers, whereas DWI performance for ascertaining clear cell histologic grade remains unclear. To develop DWI as a noninvasive approach for the evaluation of solid renal masses, prospective studies with standardized test parameters are needed to better establish DWI performance and its impact on patient outcomes.

OBJECTIVE. The objective of this study was to quantify the effects of radiation-induced cancer risks in patients with Bosniak category IIF lesions undergoing CT versus MRI surveillance. MATERIALS AND METHODS. We developed a Markov-Monte Carlo model to determine life expectancy losses attributable to radiation-induced cancers in hypothetical patients undergoing CT versus MRI surveillance of Bosniak IIF lesions. Our model tracked hypothetical patients as they underwent imaging surveillance for up to 5 years, accounting for potential lesion progression and treatment. Estimates of radiation-induced cancer mortality were generated using a published organ-specific radiation-risk model based on Biological Effects of Ionizing Radiation VII methods. The model also incorporated surgical mortality and renal cancer-specific mortality. Our primary outcome was life expectancy loss attributable to radiation-induced cancers. A sensitivity analysis was performed to assess the stability of the results with variability in key parameters. RESULTS. The mean number of examinations per patient was 6.3. In the base case, assuming 13 mSv per multiphase CT examination, 64-year-old men experienced an average life expectancy decrease of 5.5 days attributable to radiation-induced cancers from CT; 64-year-old women experienced a corresponding life expectancy loss of 6.9 days. The results were most sensitive to patient age: Life expectancy loss attributable to radiation-induced cancers increased to 21.6 days in 20-year-old women and 20.0 days in 20-year-old men. Varied assumptions of each modality's (CT vs MRI) depiction of lesion complexity also impacted life expectancy losses. CONCLUSION. Microsimulation modeling shows that radiation-induced cancer risks from CT surveillance for Bosniak IIF lesions minimally affect life expectancy. However, as progressively younger patients are considered, increasing radiation risks merit stronger consideration of MRI surveillance.

AIM: To evaluate the performance of multidetector computed tomography (MDCT) in the measurement of endometrial thickness and assessment for endometrial disease. MATERIALS AND METHODS: Seventy-nine MDCT examinations, including sagittal reformats from isotropic data, were retrospectively evaluated for the presence of endometrial abnormality, endometrial thickness, and recommendation for transvaginal ultrasound (TVUS) after CT. The endometrial thickness was measured on sagittal images using two different methods, between the inner-to-inner hypoattenuating stripe, and when visible, between the outer-to-outer hyperattenuating stripe. TVUS performed within 48 h of CT in premenopausal and 1 month in postmenopausal patients served as reference standard. Interobserver agreement for endometrial thickness and abnormalities was assessed using concordance correlation (CC) and kappa statistics. RESULTS: Interobserver agreement for endometrial thickness on sagittal CT images was excellent (CC 0.98), and highly accurate using the inner-to-inner measurement. For determination of abnormal thickening, the positive predictive value and negative predictive value were 67-100% and 99.5-100%. For detection of any endometrial abnormality, the positive predictive value and negative predictive value were 79-90% and 84-95%, respectively. False-negative missed abnormalities included small volume hydrometra, a polyp, and endometrial distortion by a fibroid. CONCLUSION: At MDCT, sagittal reformatted images provide reliable endometrial measurement using the inner-to-inner hypoattenuating stripe and are accurately categorized as normal or abnormal thickness using the same numerical criteria as at sonography.