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 objective of our study was to perform a systematic review and meta-analysis of the diagnostic performance of MRI in differentiation of papillary renal cell carcinoma (RCC) from other renal masses. MATERIALS AND METHODS/METHODS:We performed searches of three electronic databases for studies that used MRI techniques to differentiate papillary RCC from other renal lesions. Methodologic quality was assessed, and diagnostic test accuracy was summarized using bivariate random-effects modeling or with construction of a summary ROC (SROC) curve. RESULTS:Thirteen studies involving 275 papillary RCC lesions and 758 other renal masses met the inclusion criteria. Resulting summary estimates for the performance of MRI to differentiate papillary RCC from other renal lesions were a sensitivity of 79.6% (95% CI, 62.3-90.2%) and specificity of 88.1% (95% CI, 80.1-93.1%). In subgroup analysis, quantitative pooling of seven studies using enhancement in the corticomedullary phase resulted in a sensitivity of 85.6% (95% CI, 67.8-94.4%), specificity of 91.7% (95% CI, 76.0-97.5%), and area under the SROC curve of 0.894. Four studies used tumor appearance on T2-weighted imaging to detect papillary RCC, and results showed a pooled sensitivity of 89.9% (95% CI, 73.0-96.7%) and specificity of 84.9% (95% CI, 69.0-93.4%). Three studies used signal loss on T1-weighted in-phase imaging to detect papillary RCC but marked heterogeneity precluded pooling. CONCLUSION/CONCLUSIONS:Meta-analysis supports moderate sensitivity and excellent specificity of quantitative enhancement in the corticomedullary phase for differentiating papillary RCC from other tumors. The accuracy of combining enhancement and T2 signal-intensity characteristics merits further evaluation as a potential aid for management decisions.

PURPOSE/OBJECTIVE:The aim of this study was to assess changing Medicare volumes of, and coverage for, secondary interpretations of diagnostic imaging examinations stratified by modality and body region service families. METHODS:Medicare Physician/Supplier Procedure Summary Master Files for 2003 to 2016 were obtained. Aggregate Part B fee-for-service claims frequency and payment data were isolated for noninvasive diagnostic imaging and stratified by service family. Using published Medicare payment rules, secondary interpretations were identified as studies billed using both modifiers 26 and 77. Billed and denied services volumes were calculated and compared across modality and body region service families. RESULTS:Seven service families showed a compound annual growth rate from 2003 to 2016 of >20% (an additional 12 service families, >10% growth). For select high-volume service families (chest radiography and fluoroscopy [R&F], brain MRI, and abdominal and pelvic CT), relative growth in billed secondary interpretation services exceeded that for primary interpretations. In 2016, body region and modality service families with the most billed secondary interpretations were chest R&F (674,124), abdominal and pelvic R&F (65,566), brain CT (45,642), extremity R&F (34,560), abdominal and pelvic CT (14,269), and chest CT (10,914). All service families had secondary interpretation denial rates <25% in 2016 (15 service families, <10%). CONCLUSIONS:Among Medicare beneficiaries, the frequency of billed secondary interpretation services for diagnostic imaging services increased from 2003 to 2016 across a broad range of modalities and body regions, often dramatically. Payment denial rates were consistently low across service families. As CMS continues to seek input on appropriate coverage for these services, these findings suggest increasing clinical demand for and payer acceptance of these value-added radiologist services.

Purpose To retrospectively assess whether there is an association between screening mammography and the use of a variety of preventive services in women who are enrolled in Medicare. Materials and Methods U.S. Medicare claims from 2010 to 2014 Research Identifiable Files were reviewed to retrospectively identify a group of women who underwent screening mammography and a control group without screening mammography in 2012. The screened group was divided into positive versus negative results at screening, and the positive subgroup was divided into false-positive and true-positive findings. Multivariate logistic regression models and inverse probability of treatment weighting were used to examine the relationship between screening status and the probabilities of undergoing Papanicolaou test, bone mass measurement, or influenza vaccination in the following 2 years. Results The cohort consisted of 555 705 patients, of whom 185 625 (33.4%) underwent mammography. After adjusting for patient demographics, comorbidities, geographic covariates, and baseline preventive care, women who underwent index screening mammography (with either positive or negative results) were more likely than unscreened women to later undergo Papanicolaou test (odds ratio [OR], 1.49; 95% confidence interval: 1.40, 1.58), bone mass measurement (OR, 1.70; 95% confidence interval: 1.63, 1.78), and influenza vaccine (OR, 1.45; 95% confidence interval: 1.37, 1.53). In women who had not undergone these preventive measures in the 2 years before screening mammography, use of these three services after false-positive findings at screening was no different than after true-negative findings at screening. Conclusion In beneficiaries of U.S. Medicare, use of screening mammography was associated with higher likelihood of adherence to other preventive guidelines, without a negative association between false-positive results and cervical cancer screening.

PURPOSE/OBJECTIVE:To conduct a meta-analysis of studies investigating discrepancy rates and clinical impact of imaging secondary interpretations and to identify factors influencing these rates. METHODS:EMBASE and PubMed databases were searched for original research investigations reporting discrepancy rates for secondary interpretations performed by radiologists for imaging examinations initially interpreted at other institutions. Two reviewers extracted study information and assessed study quality. Meta-analysis was performed. RESULTS:Twenty-nine studies representing a total of 12,676 imaging secondary interpretations met inclusion criteria; 19 of these studies provided data specifically for oncologic imaging examinations. Primary risks of bias included availability of initial interpretations, other clinical information, and reference standard before the secondary interpretation. The overall discrepancy rate of secondary interpretations compared with primary interpretations was 32.2%, including a 20.4% discrepancy rate for major findings. Secondary interpretations were management changing in 18.6% of cases. Among discrepant interpretations with an available reference standard, the secondary interpretation accuracy rate was 90.5%. The overall discrepancy rates by examination types were 28.3% for CT, 31.2% for MRI, 32.7% for oncologic imaging, 43.8% for body imaging, 39.9% for breast imaging, 34.0% for musculoskeletal imaging, 23.8% for neuroradiologic imaging, 35.5% for pediatric imaging, and 19.7% for trauma imaging. CONCLUSION/CONCLUSIONS:Most widely studied in the context of oncology, imaging secondary interpretations commonly result in discrepant interpretations that are management changing and more accurate than initial interpretations. Policymakers should consider these findings as they consider the value of, and payment for, secondary imaging interpretations.

Purpose: To compare the effectiveness of standard treatment using partial nephrectomy and personalized management strategies for small renal tumors using a simulation model.
Material(s) and Method(s): A decision-analytic model was constructed to compare life expectancy of management strategies for small renal tumors using: (1) uniform treatment with partial nephrectomy; or personalized options incorporating (2) percutaneous ablation; (3) biopsy, with triage of renal cell carcinoma (RCC) to nephron-sparing therapy; (4) watchful waiting for growth; and (5) MRI-based selection of papillary RCC for watchful waiting. The model included patient age, gender, chronic kidney disease (CKD) stage, renal functional decline specific to treatment type, comorbidities, benign and malignant tumors, RCC subtypes, and differential risks of cancer progression. Decisionmaking based on histologic subtype from biopsy was tested in sensitivity analysis.
Result(s): Partial nephrectomy was favored in patients of all ages with normal renal function. Otherwise, personalized strategies improved life expectancy compared with partial nephrectomy. The favorability of personalized therapy depended upon CKD stage, tumor anatomy and comorbidities. For example, patients with CKD stages 2 or 3a and moderate or high tumor anatomic complexity were most effectively treated with MRI-based management when they had no comorbidities (+ 2.57 years for MRI vs. partial nephrectomy in CKD 3a, Nephrometry Score 10), but with Charlson Comorbidity Index >=1, biopsy or watchful waiting for growth were most effective. Biopsy-based management became most effective in multiple patient subcategories when histologic subtype guided treatment selection.
Conclusion(s): Personalized treatment selection for small renal tumors likely improves life expectancy for patients with abnormal renal function

In the management of epithelial ovarian cancers, imaging is used for cancer detection and staging, both before and after initial treatment. The decision of whether to pursue initial cytoreductive surgery for ovarian cancer depends in part on accurate staging. Contrast-enhanced CT of the abdomen and pelvis (and chest where indicated) is the current imaging modality of choice for the initial staging evaluation of ovarian cancer. Fluorine-18-2-fluoro-2-deoxy-d-glucose PET/CT and MRI may be appropriate for problem-solving purposes, particularly when lesions are present on CT but considered indeterminate. In patients who achieve remission, clinical suspicion for relapse after treatment prompts imaging evaluation for recurrence. Contrast-enhanced CT is the modality of choice to assess the extent of recurrent disease, and fluorine-18-2-fluoro-2-deoxy-d-glucose PET/CT is also usually appropriate, as small metastatic foci may be identified. If imaging or clinical examination confirms a recurrence, the extent of disease and timing of disease recurrence then determines the choice of treatments, including surgery, chemotherapy, and radiation therapy. 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.

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.