OBJECTIVE: The purpose of our study was to evaluate the combination of dynamic contrast-enhanced T1-weighted and double-echo gradient-echo MR imaging to distinguish renal oncocytoma with high T2 signal intensity centrally from renal cell carcinoma (RCC).
MATERIALS AND METHODS: Between 2006 and 2011, 63 renal tumors (59 patients) presenting with a high signal intensity (SI) central area on T2-weighted sequences were imaged with dynamic contrast-enhanced sequences, including phases later than 5 minutes after contrast injection, and double-echo chemical-shift sequences were selected from our institutional database. Two experienced radiologists visually assessed presence and distribution of signal enhancement of central areas after injection and measured SI changes on opposed-phase images for calculation of the SI index and tumor-to-spleen ratio. Cutoff values were derived from the receiver operating characteristic (ROC) curve.
RESULTS: There were 19 oncocytomas (16 patients), 43 RCCs (42 patients), and one leiomyoma. Complete late enhancement of the central area was observed in 14 oncocytomas (74%) and in five RCCs (12%) (p = 0.05). The combination of complete enhancement and SI index lower than 2% (p = 0.02) or tumor-to-spleen ratio higher than -6% (p = 0.001) provided sensitivity of 36% and 55%, specificity of 95% and 97%, positive predictive value of 67% and 86%, and negative predictive value of 84% and 88%, respectively, for diagnosis of oncocytomas.
CONCLUSION: Absence of central area SI inversion or presence of a signal drop on chemical-shift imaging may rule out the diagnosis of oncocytoma.
Written by:
Cornelis F, Lasserre AS, Tourdias T, Deminière C, Ferrière JM, Le Bras Y, Grenier N. Are you the author?
Department of Radiology, Pellegrin Hospital, Pl Amélie Raba Léon, 33076 Bordeaux, France.
Reference: AJR Am J Roentgenol. 2013 Apr;200(4):830-8.
doi: 10.2214/AJR.12.9122
PubMed Abstract
PMID: 23521457
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