The strategy for improving the detection of minute renal cell carcinoma with contrast-enhanced ultrasonography / 中华超声影像学杂志

ABSTRACT

Objective:To investigate the value of contrast-enhanced ultrasonography (CEUS) in detecting minute renal cell carcinoma (MRCC) smaller than 15 mm (by ultrasonic measurement) and the strategy to improve its detection rate.Methods:Fifty-three pathologically confirmed MRCCs by surgery from November 2007 to October 2019 at Zhongshan Hospital of Fudan University were enrolled in this retrospectively study. All of them underwent both conventional ultrasound and CEUS examinations. The clinical and imaging data were collected and analyzed. Common features, such as tumor size, location, echogenicity, morphology, border, and blood flow signals were observed on conventional ultrasound. On CEUS, the presence of enhancement, wash in and wash out pattern, perfusion uniformity within the lesions were observed.Results:Post-operative pathology confirmed 48 clear cell carcinomas, 4 papillary carcinomas, and 1 chromophobe cell carcinoma. On conventional ultrasound, 12/53 lesions showed no protrusion out of the kidney, and 41/53 cases slightly protruded out of the kidney. There was considerable difficulty in the detection of ten lesions, which was achieved with the guidance of CT/MRI, due to their dorsal location of the kidney. On conventional ultrasound, solid, hyper-echoic, color flow signal with varying degrees were the main features of MRCC.The boundary could be well- or ill-defined, and cystic changes existed in part of cases. On CEUS, most MRCCs showed simultaneous enhancement in cortical phase, iso- to hyper-enhancement at peak, and rapid washout in parenchymal phase. The comparisons of imaging features demonstrated that the characteristics were significantly different between conventional ultrasound and CEUS with regard to boundaries, blood supply, and perfusion uniformity (χ 2=12.425, 20.247, 7.185; all P<0.01). Conclusions:CEUS can significantly improve the detection rate of MRCC, which is superior to conventional ultrasound.