In-Phase Signal Intensity Loss in Solid Renal Masses on Dual-Echo Gradient-Echo MRI: Association With Malignancy and Pathologic Classification

Abstract

Visible in-phase signal intensity loss is relatively common within solid renal masses and was associated with RCC and particularly papillary RCC (among all RCCs) in our population. Quantitative analysis in lesions without visible signal intensity loss was not predictive of RCC. Further work should be performed to validate the usefulness of this additional imaging parameter to help characterize renal masses and to determine the impact of this finding on imaging techniques potentially sensitive to susceptibility effects.

Evaluation of T1-Weighted MRI to Detect Intratumoral Hemorrhage Within Papillary Renal Cell Carcinoma as a Feature Differentiating From Angiomyolipoma Without Visible Fat

“…The greater the decrease in SI on in-phase images versus opposed-phase images, the more negative the value of the SI loss index was likely to be. The expected loss of SI related to the longer TE of the in-phase sequence was considered negligible in the present study, as has been reported in previously published studies [36,37]. Standardized ROI placement was used, rather than measurement of areas of a visible decrease in SI, to determine whether there is any additional benefit of quantitative versus subjective analysis.…”

“…Yoshimitsu et al [36] first reported the use of chemical-shift MRI (i.e., detection of susceptibility artifact on the longer-TE in-phase image, compared with the shorter-TE opposed-phase image) as a finding associated with RCC and, in particular, with papillary RCC [36]. More recently, this finding was reevaluated by Childs et al [37], who also concluded that this finding was specific for RCC and that it was more common in papillary tumors, with histologic analysis confirming its association with the presence of intratumoral hemorrhage.…”

“…The lesion characteristics used in the histopathologic diagnosis of papillary RCC and AML have been described elsewhere [6,[40][41][42]. We did not reevaluate the papillary RCCs for the presence of intratumoral hemorrhage at the time of histopathologic analysis because this finding had been validated repeatedly elsewhere [23,34,36,37].…”

“…The SI ratios on T2-weighted and fat-suppressed T1-weighted MR images were calculated using the following equation: SI tumor / SI cortex [17]. For chemical-shift MRI, the SI loss index was calculated as described elsewhere [37], with the use of the following equation: [(SI tumorIP − SI tumorOP ) / SI tumorOP ] × 100, where IP denotes the in-phase image and OP denotes the opposed-phase image. The greater the decrease in SI on in-phase images versus opposed-phase images, the more negative the value of the SI loss index was likely to be.…”

Renal Mass Biopsy in the Era of Surgical Alternatives

“…A recent study suggests that the detection of intracellular hemosiderin with MRI is highly specific for the diagnosis of renal malignancies; in particular papillary RCCs [35]. Hemosiderin is characterized by relative signal loss within a tumor on in-phase MR images, and its detection obviates the need for biopsy (Fig.…”