Initial experience with arterial spin-labeling MR imaging to assess histology of renal masses.

It is standard practice to presume that solid renal tumors are malignant and perform a nephrectomy without a biopsy. In many clinical situations, renal biopsies lack sufficient diagnostic accuracy to justify altering management. Lanzman and colleagues propose the use of arterial spin-labeling magnetic resonance imaging to assess renal histology and grade. They used histopathologic data as the reference standard, and reported a statistically significant difference in measured tumor perfusion between papillary renal tumor, oncocytomas, and all other histologic subtypes examined. If confirmed in larger studies, this imaging modality may play a role in triaging patients with solid renal masses for surgery or renal biopsy.