Novel ultrasonographic evaluation of microvascular blood flow for the non-operative management of uncomplicated acute appendicitis in children

Abstract

Abstract Background: Superb microvascular imaging (SMI), in contrast to power Doppler (PD), enables visualization of microvascular blood flow (BF). We compared PD and SMI to determine whether SMI is superior in detecting appendiceal BF in uncomplicated acute appendicitis patients. Methods: We prospectively reviewed all pediatric patients with acute appendicitis initially treated non-operatively and clinically evaluated using PD and SMI to determine the case severity, monitor appendiceal BF, and assess the reversibility of appendicitis. Complicated acute cases were excluded. Severity was classified using B-mode, PD ultrasonography, and additional SMI: Grade I - smooth wall/normal BF, Grade IIa - irregular wall/increased BF, Grade IIb - irregular wall/decreased BF, and Grade III - absence of wall/loss of BF. SMI results were compared with those of PD alone. Results: 129 patients with acute appendicitis were reviewed; 29 were excluded. In 100 patients (Grade I: 10, IIa: 29, IIb: 55, III: 6), no differences were observed between PD and SMI in appendiceal BF for Grades I and IIa, which all fully recovered. In all 55 patients with Grade IIb and decreased appendiceal BF on PD, SMI effectively detected appendiceal BF, and 52 recovered. Neither PD nor SMI were able to detect BF in Grade III patients who developed abscesses and for whom non-operative management failed. Conclusions: SMI can accurately detect BF, even when decreased BF is observed by PD. SMI showed a higher sensitivity in detecting appendiceal BF compared to PD and may serve as a tool for patient selection for non-operative management of acute appendicitis.