Visualisation of focal renal lesions on ultrasound: A review of 518 lesions with contrast CT correlation.

introductionConventional ultrasound (US) is a common imaging investigation of the kidneys; however, the current diagnostic performance of US in the visualisation of focal renal lesions is unknown.

methodsThis study was a retrospective sequential review of 518 focal renal lesions (FRLs) in 200 patients aged 50 years or older who received an US of the kidneys followed by contrast-enhanced computed tomography (CECT).

resultsPatient's age ranged from 50 to 94 years. The majority were hospital inpatients. 518 FRLs were identified on CECT ranging from 3 to 165 mm (median 8 mm). The majority of FRLs (96.1%) were benign. The visualisation rate of FRLs on US was size-dependent: <5 mm, 10.2%; 5-9 mm, 22.3 mm; 10-14 mm, 48.0%; 15-19 mm, 82.1%; and 20-24 mm, 100%. The visualisation of simple cysts was 49.1% and hyperdense lesions 81.8%. Follow-up was available on 58% of lesions. Benign lesions generally remained stable. Seven patients had concerning heterogeneous hyperdense masses on CECT, and US had visualised six of these (85.7%).

conclusionVisualisation of FRLs is size-dependent. High rate of visualisation is achieved once the lesion exceeds 15 mm in size. Small FRLs are associated with a low rate of visualisation on ultrasound; however, they are rarely concerning. Hyperdense lesions on CECT that carry high suspicion of malignancy are associated with a high rate of US visualisation.