gms | German Medical Science

Objective: We evaluated the ability of contrast-enhanced ultrasound perfusion imaging (UPI) to detect normo-, hypo-, and non-perfused brain regions after acute ischemic stroke (middle cerebral artery syndrome).

Method: We prospectively acquired high mechanical index (HighMI) contrast-enhanced UPI and perfusion weighted imaging (PWI) or perfusion computed tomography (CTP) data in 30 acute stroke patients prior to endovascular therapy. This was a single-center study. Time-to-peak intensity of 10 regions of interest (ROIs) in the ischemic hemisphere were compared with 4 standard ROIs from the non-ischemic hemisphere of the same patient and were categorized as normal perfused, hypoperfused, or non-perfused (UPI threshold: 3s; PWI/CTP threshold: 4s).

Results: Sixteen patients were used for the final analysis. Among UPIs with HighMI detected from 160 ROIs in the ischemic hemisphere, 98 ROIs were normal perfused and 52 were hypoperfused and non-perfused (10 ROIs were excluded because of artifacts); these numbers significantly correlated with the PWI/CTP ROIs detection (Pearson's chi-squared test 79.119, p<0.001). Eighteen ROIs showed no perfusion, correlating with the diffusion-weighted imaging positive ROIs on MRI (Pearson's chi-squared test 42.307, p<0.001). Analysis of receiver operating characteristics proved a high sensitivity of HighMI UPI in the diagnosis of hypoperfused (AUC = 0.917; p<0.001) and non-perfused (AUC = 0.830; p<0.001) tissue in comparison with PWI (hypoperfused) and diffusion-weighted imaging (non-perfused) sequences.

Conclusions: Our study establishes UPI with HighMI as a highly specific and sensitive method for detecting hypoperfused and non-perfused areas, when compared with the gold standard in a setting of acute ischemic stroke.