CT algorithm for clear-cell renal cell carcinoma in small solid masses

American Roentgen Ray Society

Leesburg, VA, June 29, 2022—According to ARRS’ American Journal of Roentgenology (AJR), a 5-tiered CT scoring algorithm may represent a clinically useful tool for diagnosis of clear-cell renal cell carcinoma (RCC) in small (≤4 cm) solid renal masses.

“A 5-tiered renal CT algorithm, including mass-to-cortex corticomedullary attenuation ratio and heterogeneity score, had substantial inter-observer agreement, moderate AUC and PPV, and high NPV for diagnosing clear-cell RCC,” concluded Nicola Schieda from the department of medical imaging at Canada’s Ottawa Hospital.

Schieda and colleagues’ study included 148 patients (mean age, 58 years; 73 men, 75 women) with 148 small (≤4 cm) solid (>25% enhancing tissue) renal masses that underwent renal-mass CT (unenhanced, corticomedullary, and nephrographic phases) before resection between January 2016 and December 2019. Two radiologists independently evaluated CT examinations and recorded calcification, mass attenuation in all phases, mass-to-cortex corticomedullary attenuation ratio, and heterogeneity score (5-point Likert scale, assessed in corticomedullary phase).

Ultimately, Schieda et al’s 5-tiered CT scoring algorithm—including mass-to-cortex corticomedullary attenuation ratio and heterogeneity score—had substantial interobserver agreement (weighted kappa=0.71) and achieved AUC for diagnosing clear-cell RCC of 0.75 (95% CI, 0.68-0.82) for reader 1 and 0.72 (95% CI, 0.66-0.82) for reader 2.

“If validated,” the authors of this AJR article acknowledged, “the CT algorithm may represent a useful clinical tool for diagnosing clear-cell renal cell carcinoma.”


North America’s first radiological society, the American Roentgen Ray Society (ARRS) remains dedicated to the advancement of medicine through the profession of medical imaging and its allied sciences. An international forum for progress in radiology since the discovery of the x-ray, ARRS maintains its mission of improving health through a community committed to advancing knowledge and skills with the world’s longest continuously published radiology journal—American Journal of Roentgenology—the ARRS Annual Meeting, InPractice magazine, topical symposia, myriad multimedia educational materials, as well as awarding scholarships via The Roentgen Fund®.

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