Small solid renal masses: Characterization by diffusion-weighted MRI at 3 T

DWI for Renal Mass Characterization: Systematic Review and Meta-Analysis of Diagnostic Test Performance

“…Unclear risks arose from methods in four studies in which readers measured ADC values in consensus or in which the authors did not specify whether readers worked independently or in consensus [18,19,22,23]. Risks were considered unclear in four studies using 3-T scanners instead of 1.5-T scanners [8,16,19,21].…”

“…In one study, all malignancies were solid lesions only and all benign lesions were cysts and abscesses [7]; in another study, only lesions that appeared hyperintense on T1-weighted imaging were tested [6]. Two studies performed at 3 T [16,19] performed substantially worse than studies performed at 1.5 T. After logistic transformation, the summary and difference plot analyses revealed substantial heterogeneity in test performance in these four studies after controlling for variable ADC thresholds.…”

“…Unclear risks of bias arose in several studies that allowed different reference standards for the diagnosis of positive and negative disease. These differences in reference standards included the use of surgical pathology versus percutaneous biopsy results, the use of imaging only for lesions considered to be Bosniak category II cysts, or the use of follow-up imaging for establishing benignity of Bosniak IIF cystic lesions [5,7,[16][17][18][19]. These differences in reference standards may have allowed incorrect classification in which lesions were presumed benign but possibly were indolent malignancies (e.g., oncocytic tumors diagnosed at biopsy or on imaging follow-up of variable lengths for complex renal cystic lesions) [20].…”

Multiparametric MRI of solid renal masses: pearls and pitfalls

“…Both classic triphasic AML and minimalfat AMLs may show profound diffusion restriction, 56 with similar ADC values compared to p-RCC. In classic AML, the presence of macroscopic fat is diagnostic (Fig 10).…”

Imaging of renal cell carcinoma

“…There are encouraging solutions, however, to this potential limitation as chronic cysts can be readily detected on T1W MRI as hyperintense lesions, which often remain stable over several imaging examinations and infectious etiology can be determined based on patient history and laboratory findings [46,[51][52][53]. Furthermore, certain types of AML may exhibit restricted diffusion as well, such as those containing minimal fat [54]. These subtypes may have ADC values comparable to those of pRCCs; however, minimal fat and fat-poor variants constitute only 5% of AMLs [55][56][57].…”