Renal cell carcinoma: diffusion-weighted MR imaging for subtype differentiation at 3.0 T

Area of Science:

• Radiology
• Oncology
• Medical Imaging

Background:

• Renal cell carcinoma (RCC) comprises various subtypes with distinct clinical behaviors.
• Accurate preoperative characterization of RCC subtypes is crucial for optimal treatment planning.
• Diffusion-weighted (DW) magnetic resonance (MR) imaging offers insights into tissue microstructure.

Purpose of the Study:

• To evaluate the utility of apparent diffusion coefficients (ADCs) derived from 3.0-T DW MR imaging in differentiating subtypes of renal cell carcinoma (RCC).
• To determine if ADCs can reliably distinguish between clear cell, papillary, and chromophobic RCC.
• To assess the diagnostic performance of ADCs in preoperative RCC characterization.

Main Methods:

• Retrospective analysis of DW MR imaging data from 83 patients with 85 renal masses.
• DW imaging was performed at 3.0 T using b values of 0 and 500 sec/mm(2), and 0 and 800 sec/mm(2).
• Apparent diffusion coefficients (ADCs) were calculated and compared across RCC subtypes using statistical analysis, including receiver operating characteristic (ROC) curve analysis.

Main Results:

• Clear cell RCC exhibited significantly higher mean ADCs compared to papillary and chromophobic RCC at b values of 0 and 500 sec/mm(2).
• At b values of 0 and 800 sec/mm(2), clear cell RCC consistently showed the highest mean ADC, with significant differences between all subtype pairs.
• ROC analysis demonstrated high accuracy (area under the curve = 0.973) for differentiating clear cell from non-clear cell RCC using ADCs with b values of 0 and 800 sec/mm(2), achieving 95.9% sensitivity and 94.4% specificity at a threshold of 1.281 × 10(-3) mm(2)/sec.

Conclusions:

• Diffusion-weighted imaging (DWI) at 3.0 T, particularly with b values of 0 and 800 sec/mm(2), enables sensitive and specific differentiation of major RCC subtypes.
• Apparent diffusion coefficients (ADCs) are valuable quantitative biomarkers for characterizing RCC.
• DW imaging holds promise as a non-invasive tool for preoperative assessment and subtyping of renal cell carcinoma.