Characterizing solid renal neoplasms with MRI in adults

Abstract

Until recently, most solid renal neoplasms without macroscopic fat were presumed to represent renal cell carcinoma and were indiscriminately treated with nephrectomy. Expanding surgical options and ablative technologies, a growing acceptance of renal mass biopsy, the advent of targeted molecular agents, and advances in our understanding of tumor biology have challenged the wisdom of this approach and are ushering in a potential new era in which therapy is linked to histologic subtype and cytogenetics. This approach mandates evolution of our diagnostic algorithm beyond the distinction between solid and cystic and enhancing and nonenhancing. Computed tomography (CT) has traditionally been the imaging technique of choice for evaluating potential solid renal tumors, in large part due to its widespread availability, high spatial resolution, calcium discrimination, and multiphase, enhanced imaging capabilities. For the most part, however, CT is limited to characterization based upon the attenuation and enhancement characteristics of a lesion and necessitates exposure of patients to ionizing radiation. For these latter reasons, multiparametric magnetic resonance imaging (MRI) is being increasingly used to characterize solid renal masses. The purpose of this manuscript is to review our imaging approach to solid renal masses in adults utilizing MRI with an emphasis on a multiparametric approach augmented by clinical data.

Renal Mass Biopsy in the Era of Surgical Alternatives

“…They may show signal loss on opposed-phase MR imaging [17,18]. Most RCCs, particularly the clear cell subtype, have high signal intensity on T2-weighted images and enhance avidly [17,19]. Some clear cell RCCs show signal loss on chemical shift imaging [17,20], but the other MRI features are distinctively different from AMLs.…”

“…Most RCCs, particularly the clear cell subtype, have high signal intensity on T2-weighted images and enhance avidly [17,19]. Some clear cell RCCs show signal loss on chemical shift imaging [17,20], but the other MRI features are distinctively different from AMLs. Papillary RCCs do have MRI features that overlap with AMLs, in particular low signal intensity on T2-weighted MR images [17,19,21], and hence biopsy is used to distinguish these from AMLs.…”

“…AMLs usually have low signal intensity on T2-weighted images and variable enhancement after gadolinium injection [15][16][17]. They may show signal loss on opposed-phase MR imaging [17,18]. Most RCCs, particularly the clear cell subtype, have high signal intensity on T2-weighted images and enhance avidly [17,19].…”

“…Fat-poor AMLs have MR features that can suggest biopsy rather than unneeded resection or ablation. AMLs usually have low signal intensity on T2-weighted images and variable enhancement after gadolinium injection [15][16][17]. They may show signal loss on opposed-phase MR imaging [17,18].…”

Nichtinvasive Phänotypisierung von Nierentumoren – aktueller Stand

“…In über 50 % der Fälle zeigt es eine zentrale, radspeichenartige Narbe, welche ebenfalls hypointens in der T1w und hyperintens in der T2w ist und Kontrastmittel aufnimmt. Die KMAffinität des Onkozytoms ist kräftig, die KM-Dynamik variabel: Es können Areale mit initial starker und solche mit verzögerter KM-Aufnahme im selben Tumor vorkommen [1,12]. Die DWI ist zur Unterscheidung zwischen dem Onkozytom und dem RCC aufgrund starker Überschneidungen insbesondere zum klarzelligen RCC nur eingeschränkt Der Radiologe 10 · 2018 903…”