Hyperdense Renal Lesion Characterization on Three DECT Technologies: Can Iodine Quantification Differentiate...

To evaluate the performance of dual-energy computed tomography (DECT) in differentiation of hyperattenuating renal cysts (HCs) from papillary renal cell cancers (pRCCs) on three different DECT technologies (dual-source [dsDECT], rapid kVp-switching [rsDECT], and dual-layer detector-based [dlDECT]).

In this institutional review board-approved retrospective study, we included 85 patients with a total of 108 incidental hyperdense renal lesions detected on contrast-enhanced DECT scans (dsDECT, n = 41; rsDECT, n = 42; and dlDECT, n = 25). The study cohort included HCs (n = 73) and pRCCs (n = 35). Final confirmation was obtained with histopathology for pRCCs and with magnetic resonance imaging within 6 months of the DECT for HCs. Quantitative iodine evaluation was performed with iodine concentration (IC) measured within the lesion and the abdominal aorta. Normalized IC (NIC) was generated for each lesion by normalizing the lesion IC to the aortic IC.

Both IC and NIC measurements yielded significant differences between HCs and pRCCs for the dsDECT and rsDECT techniques (P < 0.001) but not for the dlDECT (P > 0.05). Cutoff values with 100% sensitivity for pRCC detection were 0.30 and 0.60 mg/mL for dsDECT and rsDECT, respectively. Normalization to the abdominal aorta allowed creation of a uniform cutoff on both technologies, with an NIC value of 0.09 allowing 100% sensitivity for each.

Significant intertechnique differences exist for the differentiation of HCs from pRCCs. Normalization of IC to the aorta provides a uniform cutoff for differentiation of these lesions on dsDECT and rsDECT.