Ultrasound Correlates Highly With Cross Sectional Imaging for Small Renal Masses in a Contemporary Cohort

To determine the correlation between ultrasound (US), cross-sectional imaging, and pathological renal mass sizes.Between January 2011 and January 2021, a cohort of patients from 14 academic institutions who had an US and cross-sectional imaging within 8 weeks of each other and within 6 months of surgery were identified. A second cohort of patients with small renal masses (≤4 cm) who had US and cross-sectional imaging within 8 weeks of each other were also examined, regardless of their treatment modality. Correlation coefficients, Bland-Altman plots, and sensitivity tables were generated.A total of 1464 patients were included in the surgical cohort and 1582 patients (1921 imaging pairs) were included in the small renal mass (SRM) cohort. Pearson correlation coefficients between computed tomography (CT)/magnetic resonance imaging (MRI) and pathologic size was 0.93 (P.0001) and between US and pathological size was 0.90 (P.0001). The correlation between US and CT/MRI was 0.93 (P.0001). Bland-Altman plots demonstrated a greater agreement for smaller renal masses. For the SRM cohort when comparing US to CT/MRI, 1441 (75%) SRM measurements were within 0.5 cm and only 149 (7.8%) were greater than 1 cm in difference. Subgroup analysis demonstrated that correlation between US and CT/MRI for SRMs were higher in patients with lower body mass index.There is a strong correlation between US and cross-sectional imaging in 75% of patients at baseline imaging. Our study provides support for utilization of US for active surveillance.