Radiography Intravenous Urography There is no relevant literature regarding the use of IVU for the evaluation of indeterminate renal masses. US Abdomen with IV Contrast CEUS using microbubble agents is emerging as a useful way to characterize previously indeterminate renal lesions [16-18]. In one study of 1,018 indeterminate renal lesions, CEUS had a per patient sensitivity of 100% (126 of 126 patients), specificity of 95% (132 of 139 patients), positive predictive value of 94.7% (126 of 133 patients), and negative predictive value of 100% (132 of 132 patients) for classifying benign versus malignant renal masses [16]. In that study, any echogenic masses with enhancement at least of normal renal cortex and wash-out, as well as any masses with blood flow, were considered malignant. In another study, CEUS successfully classified 95.7% (90 of 94) previously indeterminate lesions, and had an accuracy of 90.2% (37 of 41 lesions) when compared with the reference standard, including histopathology and follow-up [18]. In the subgroup analysis, CEUS was definitive for 94.4% (17 of 18) of cases referred because of equivocal enhancement at CT [18]. In that same study, CEUS was able to classify lesions in 100% (10 of 10) of the cases in which the lesions were indeterminate on prior MRI [18]. Another study of CEUS in 83 CT indeterminate renal masses reported that the accuracy of characterization by CEUS was 95.2% compared with 42.2% using unenhanced US [17]. In a prospective CEUS study of 94 solid renal lesions, excluding lipid-rich AML, hypovascularity of small solid renal masses relative to the cortex in the arterial phase has 100% specificity for detecting malignancy, especially for detecting papillary RCC [66]. Quantitative analysis of CEUS has also been reported to be useful to stratify RCC and benign renal tumors [67,68]. Supporting Documents The evidence table, literature search, and appendix for this topic are available at https://acsearch. acr.org/list.
Indeterminate Renal Mass. Radiography Intravenous Urography There is no relevant literature regarding the use of IVU for the evaluation of indeterminate renal masses. US Abdomen with IV Contrast CEUS using microbubble agents is emerging as a useful way to characterize previously indeterminate renal lesions [16-18]. In one study of 1,018 indeterminate renal lesions, CEUS had a per patient sensitivity of 100% (126 of 126 patients), specificity of 95% (132 of 139 patients), positive predictive value of 94.7% (126 of 133 patients), and negative predictive value of 100% (132 of 132 patients) for classifying benign versus malignant renal masses [16]. In that study, any echogenic masses with enhancement at least of normal renal cortex and wash-out, as well as any masses with blood flow, were considered malignant. In another study, CEUS successfully classified 95.7% (90 of 94) previously indeterminate lesions, and had an accuracy of 90.2% (37 of 41 lesions) when compared with the reference standard, including histopathology and follow-up [18]. In the subgroup analysis, CEUS was definitive for 94.4% (17 of 18) of cases referred because of equivocal enhancement at CT [18]. In that same study, CEUS was able to classify lesions in 100% (10 of 10) of the cases in which the lesions were indeterminate on prior MRI [18]. Another study of CEUS in 83 CT indeterminate renal masses reported that the accuracy of characterization by CEUS was 95.2% compared with 42.2% using unenhanced US [17]. In a prospective CEUS study of 94 solid renal lesions, excluding lipid-rich AML, hypovascularity of small solid renal masses relative to the cortex in the arterial phase has 100% specificity for detecting malignancy, especially for detecting papillary RCC [66]. Quantitative analysis of CEUS has also been reported to be useful to stratify RCC and benign renal tumors [67,68]. Supporting Documents The evidence table, literature search, and appendix for this topic are available at https://acsearch. acr.org/list.