Bosniak Classification of Cystic Renal Masses, Version 2019: An Update Proposal and Needs Assessment.

Cystic renal cell carcinoma (RCC) is almost certainly overdiagnosed and overtreated. Efforts to diagnose and treat RCC at a curable stage result in many benign neoplasms and indolent cancers being resected without clear benefit. This is especially true for cystic masses, which compared with solid masses are more likely to be benign and, when malignant, less aggressive. For more than 30 years, the Bosniak classification has been used to stratify the risk of malignancy in cystic renal masses. Although it is widely used and still effective, the classification does not formally incorporate masses identified at MRI or US or masses that are incompletely characterized but are highly likely to be benign, and it is affected by interreader variability and variable reported malignancy rates. The Bosniak classification system cannot fully differentiate aggressive from indolent cancers and results in many benign masses being resected. This proposed update to the Bosniak classification addresses some of these shortcomings. The primary modifications incorporate MRI, establish definitions for previously vague imaging terms, and enable a greater proportion of masses to enter lower-risk classes. Although the update will require validation, it aims to expand the number of cystic masses to which the Bosniak classification can be applied while improving its precision and accuracy for the likelihood of cancer in each class.

Effect of Fixed-Volume and Weight-Based Dosing Regimens on the Cost and Volume of Administered Iodinated Contrast Material at Abdominal CT.

PURPOSE: To determine the magnitude of subject-level and population-level cost savings that could be realized by moving from fixed-volume low-osmolality iodinated contrast material administration to an effective weight-based dosing regimen for contrast-enhanced abdominopelvic CT. METHODS: HIPAA-compliant, institutional review board-exempt retrospective cohort study of 6,737 subjects undergoing contrast-enhanced abdominopelvic CT from 2014 to 2015. Subject height, weight, lean body weight (LBW), and body surface area (BSA) were determined. Twenty-six volume- and weight-based dosing strategies with literature support were compared with a fixed-volume strategy used at the study institution: 125 mL 300 mgI/mL for routine CT, 125 mL 370 mgI/mL for multiphasic CT (single-energy, 120 kVp). The predicted population- and subject-level effects on cost and contrast material utilization were calculated for each strategy and sensitivity analyses were performed. RESULTS: Most subjects underwent routine CT (91% [6,127/6,737]). Converting to lesser-volume higher-concentration contrast material had the greatest effect on cost; a fixed-volume 100 mL 370 mgI/mL strategy resulted in $132,577 in population-level savings with preserved iodine dose at routine CT (37,500 versus 37,000 mgI). All weight-based iodine-content dosing strategies (mgI/kg) with the same maximum contrast material volume (125 mL) were predicted to contribute mean savings compared with the existing fixed-volume algorithm ($4,053-$116,076/strategy in the overall study population, $1-$17/strategy per patient). Similar trends were observed in all sensitivity analyses. CONCLUSIONS: Large cost and material savings can be realized at abdominopelvic CT by adopting a weight-based dosing strategy and lowering the maximum volume of administered contrast material.

Indirect Cost and Harm Attributable to Oral 13-Hour Inpatient Corticosteroid Prophylaxis before Contrast-enhanced CT.

PURPOSE: To estimate the effect of an oral 13-hour inpatient corticosteroid premedication regimen on length of stay, hospital cost, and hospital-acquired infections (HAIs) by using a combination of real and hypothetical study populations. MATERIALS AND METHODS: Institutional review board approval was obtained and informed consent waived for this HIPAA-compliant retrospective study. Inpatients who received an oral 13-hour corticosteroid premedication regimen before contrast material-enhanced CT (n = 1424) from 2008 to 2013 were matched by age, sex, and year when CT was performed to a control cohort (n = 1425) of patients who underwent contrast-enhanced CT without premedication and who had similar rates of 13 comorbid diseases. Length of stay in the hospital and time from admission to CT were compared by using the Mann-Whitney U test. Rates of prospectively reported HAIs were compared by using χ(2) tests. The indirect cost and risk of HAI with premedication were estimated by using published data. RESULTS: Premedicated inpatients had a significantly longer median length of stay (+25 hours; 158 vs 133 hours, P < .001), a significantly longer median time to CT (+25 hours, 42 vs 17 hours, respectively; P < .001), and a significantly greater risk of HAI (5.1% [72 of 1424] vs 3.1% [44 of 1424], respectively; P = .008) compared with nonpremedicated control subjects. On the basis of these data and existing references, the prolonged length of stay was estimated to result in 0.04 HAI-related deaths and a cost of $159 131 (in U.S. dollars) for each prevented reaction of any severity and 32 HAI-related deaths and a cost of $131 211 400 for each prevented reaction-related death. CONCLUSION: Oral 13-hour inpatient corticosteroid prophylaxis is associated with substantial cost relative to its modest benefit, and may cause more indirect harm than the direct harm that it prevents.

Assessment of 1 mSv urinary tract stone CT with model-based iterative reconstruction.

OBJECTIVE: The purpose of this study was to evaluate stone detection, assessment of secondary signs of stone disease, and diagnostic confidence utilizing submillisievert CT with model-based iterative reconstruction (MBIR) in a North American population with diverse body habitus. MATERIALS AND METHODS: Fifty-two adults underwent stone CT using a split-dose protocol; weight-based projected volume CT dose index (CTDIvol) and dose-length product (DLP) were divided into two separate acquisitions at 80% and 20% dose levels. Images were reconstructed with MBIR. Five blinded readers counted stones in three size categories and rated "overall diagnostic confidence" and "detectability of secondary signs of stone disease" on a 0-4 scale at both dose levels. Effective dose (ED) in mSv was calculated as DLP multiplied by conversion coefficient, k, equal to 0.017. RESULTS: Mean ED (80%, 3.90±1.44 mSv; vs 20%, 0.97±0.34 mSv [p<0.001]) and number of stones detected (80%, 193.6±25.0; vs 20%, 154.4±15.4 [p=0.03]) were higher in scans at 80% dose level. Intrareader correlation between scans at 80% and 20% dose levels was excellent (0.83-0.97). With 80% scans as reference standard, mean sensitivity and specificity at 20% varied with stone size (<3 mm, 74% and 77%; ≥3 mm, 92% and 82%). The 20% scans scored lower than 80% scans in diagnostic confidence (2.46±0.50; vs 3.21±0.36 [p<0.005]) and detectability of secondary signs (2.41±0.39; vs 3.19±0.29 [p<0.005]). CONCLUSION: Aggressively dose-reduced (~1 mSv) MBIR scans detected most urinary tract stones of 3 mm or larger but underperformed the low-dose reference standard (3-4 mSv) scans in small (<3 mm) stone detection and diagnostic confidence.

Contrast medium-induced nephrotoxicity risk assessment in adult inpatients: a comparison of serum creatinine level- and estimated glomerular filtration rate-based screening methods.

PURPOSE: To compare serum creatinine (SCr) level- and estimated glomerular filtration rate (eGFR)-based screening methods for identifying adult inpatients at risk for contrast medium-induced nephrotoxicity (CIN). MATERIALS AND METHODS: Institutional review board approval was obtained; informed consent was waived for this HIPAA-compliant retrospective study. Computed tomographic examinations performed during 10 years in adult inpatients with stable renal function were identified (n = 28 390). The proportion of inpatients meeting various eGFR (≥60, <60, <45, <30, 30-44, 45-59 mL/min/1.73 m(2)) and SCr (<1.5, ≥1.5, ≥1.6, ≥1.7, ≥1.8, ≥1.9, ≥2.0 mg/dL) thresholds were contrasted with each other and with published guidelines (≥2.0 mg/dL [SCr] and <45 mL/min/1.73 m(2) [eGFR]) using McNemar and binomial tests. RESULTS: Most inpatients were considered low risk for CIN with commonly used thresholds: 92.6% (26 285 of 28 390) had SCr <1.5 mg/dL; 91.3% (25 922 of 28 390) had eGFR of ≥45 mL/min/1.73 m(2). Using SCr threshold of ≥1.5 mg/dL, identified inpatients had the following eGFRs: 19.6% (413 of 2105), 45-59 mL/min/1.73 m(2); 51.1% (1075 of 2105), 30-44 mL/min/1.73 m(2); 28.6% (603 of 2105), <30 mL/min/1.73 m(2); and 0.7% (14 of 2105), ≥60 mL/min/1.73 m(2) . Using SCr threshold of ≥2.0 mg/dL, identified inpatients had the following eGFRs: 100% (658 of 658), <45 mL/min/1.73 m(2); 74.6% (491 of 658), <30 mL/min/1.73 m(2). Threshold of SCr ≥2.0 mg/dL could not be used to identify eGFR <30 mL/min/1.73 m(2) in 0.4% (112 of 28 390) and <45 mL/min/1.73 m(2) in 6.4% (1810 of 28 390) of all inpatients. Using eGFR <45 mL/min/1.73 m(2) instead of SCr of ≥1.5 mg/dL would result in a significant but small increase in identified inpatients (8.7% [2468 of 28 390; 95% confidence interval: 8.4%, 9.0%] vs 7.4% [2105 of 28 390; 95% confidence interval: 7.1%, 7.7%]; P < .0001). CONCLUSION: Screening using eGFR <45 mL/min/1.73 m(2) instead of common SCr thresholds would significantly increase the number of inpatients identified to be at risk for CIN but would reduce misidentification of a large number of inpatients at low risk according to eGFR criteria.

Incorporating patient-centered outcomes in the analysis of cost-effectiveness: imaging strategies for renovascular hypertension.

OBJECTIVE: Our aim was to assess the contribution of patient-centered short-term disutilities and quality-of-life measures in the cost-effectiveness analysis of CT angiography, MR angiography, and conventional angiography in patients with medication-resistant hypertension. MATERIALS AND METHODS: A decision analytic model compared the life expectancy and incremental cost per life year using three initial diagnostic tests in a cohort of hypothetical individuals with medication-resistant hypertension over a range of renal artery stenosis probabilities: CT angiography (sensitivity, 96%; specificity, 96%; cost, $865); MR angiography (98%, 94%, $850); and conventional angiography (99%, 99%, $2,627). All imaging strategies were compared with a base case scenario mimicking the natural history of medication-resistant hypertension and with a scenario immediate enhanced medical therapy without prior imaging. Individuals without evidence of renal artery stenosis on initial testing underwent conventional angiography if enhanced medical therapy failed to control hypertension. Individuals diagnosed with renal artery stenosis on MR angiography required conventional angiography for definitive stent treatment ($11,1223). Blood pressure response to renal artery stenting or enhanced medical therapy varied according to blood pressure, as did the incidence of myocardial infarction and stroke resulting from hypertension. Patients who progressed to end-stage renal disease received dialysis ($60,000 per year). Quality-of-life adjustments were made for patients with hypertension, end-stage renal disease, myocardial infarction, and stroke. Short-term disutilities from undergoing an imaging test were included. The analysis accounted for direct costs derived from Medicare reimbursements and total costs derived from the literature. RESULTS: All imaging strategies were cost-effective compared with enhanced medical therapy alone or with natural history. When only direct costs were considered, MR angiography was the preferred strategy, with conventional angiography as a cost-effective alternative to MR angiography. When total costs were considered, conventional angiography dominated all other strategies. Adjusting for quality of life decreased the incremental cost-effectiveness ratios, making an already competitive strategy a more favorable alternative to the base case. Adjusting for test-related disutility did not significantly influence the cost-effectiveness of any of the imaging tests. Despite marked variation in the key clinical and cost variables, MR angiography remained the most cost-effective strategy. CONCLUSION: In the evaluation and treatment of medication-resistant hypertension, strategies that included preliminary imaging saved more lives than did the immediate institution of enhanced medical therapy at a lesser cost.