Comparison of superb micro-vascular imaging (SMI) and conventional Doppler imaging techniques for evaluating testicular blood flow

Purpose: Superb micro-vascular imaging (SMI) is a new blood flow (BF) technique recently developed to outface the limitations of conventional Doppler imaging techniques (CDIT). SMI can observe micro-vascular BF and low-velocity BF. SMI is available in two modes as color SMI (cSMI) and monochrome SMI (mSMI). To evaluate testicular BF, we have compared color Doppler (CD), power Doppler (PD), cSMI, and mSMI techniques. Patients and methods: A total of 156 patients (310 testes) were included in the study. We evaluated BF in the testes via CD, PD, cSMI, and mSMI techniques in a heterogenous patient group. Doppler examination was performed by observing the whole testis parenchyma within the examination area at the testicular hilus level at all examinations. Spot and linear flow color encoding determined in testis parenchyma were separately counted for every examination. Results: SMI was found to be superior in all age groups and testis volumes for showing the BF. When we sequenced the examinations to show the BF in testis according to their priorities, it was found that mSMI > cSMI > PD > CD. As the testis volume decreases, a significant increase is observed in mSMI when compared to other examinations in showing vascularity in pediatric age groups, in cases diagnosed with undescended testis, and in cases that underwent surgery for undescended testis. Conclusions: SMI renders more detailed vascular information on BF in the testes than CDIT. In particular, as the testis volume decreases, the priority of SMI showing BF increases. SMI should be a part of vascular examination in pediatric patients with small testis volume.