Comparative analysis of superb microvascular imaging and contrast-enhanced ultrasound in diagnosis of small renal masses

Abstract

Objective: To explore the value of superb microvascular imaging (SMI) and contrast- enhanced ultrasound (CEUS) in differential diagnosis of small renal masses. Methods: A total of 84 patients with 86 lesions of renal masses were collected from October 2016 to March 2018 in Tianjin Medical University Cancer Institute and Hospital. There were 56 males and 28 females,aged from 29 to 76 years old,with an average age of (54±10) years old. These tumors were all examined by using SMI and CEUS. And the imaging diagnostic results were compared based on the pathological results. Adler semi quantitative analysis of blood flow grading of the tumors were evaluated in SMI,and the evaluation standard was as follows:0-1 grade was benign, 2-3 grade was malignant. Besides,the patterns and enhancement of the small renal masses were observed in CEUS. The main diagnostic criteria of malignant tumors were "fast forward" , "rapid regression" and "high perfusion" . Some special types of renal cell carcinoma were diagnosed by "slow in" , "rapid regression" and "hypo-perfusion" . Benign tumors were diagnosed by "slow in" , "slow down" and "hypo-perfusion" . Results: Among 86 cases, 76 cases were confirmed as malignant masses and 10 cases were confirmed as benign masses by pathological diagnosis. By SMI, Adler grade of 89.5% (68/76) malignant tumors were 2-3, Adler grade of 6/10 benign tumors were 0-1. By CEUS, 77.6% (59/76) of malignant tumors were "fast forward" , 82.9% (63/76) were "rapid regression" , 76.3% (58/76) were "high perfusion" ; 7/10 of benign tumors were "slow in" , 5/10 were "slow down" and 6/10 were "low perfusion" . The accuracy, sensitivity, specificity, positive predictive value, negative predictive value and AUC of SMI were 86.0%,89.5%, 60.0%, 94.4%,42.9% and 0.747 respectively. The values for CEUS were 89.5%, 92.1%, 70.0%,95.9%, 53.8% and 0.811 respectively.There was no statistical difference in diagnostic efficacy between CEUS and SMI (P=0.288). Conclusions: Although there is no statistical significance between SMI and CEUS, the accuracy, sensitivity and positive predictive value of SMI in the diagnosis of small renal masses are higher,which can clearly show micro-vessels and exquisitely detect the low-velocity blood flow in small renal masses. In brief,SMI provides a new method in the differential diagnosis of small renal masses.