Systematic CT perfusion acquisition in acute stroke increases vascular occlusion detection and thrombectomy rates

Abstract

BackgroundIn patients with stroke, current guidelines recommend non-invasive vascular imaging to identify intracranial vessel occlusions (VO) that may benefit from endovascular treatment (EVT). However, VO can be missed in CT angiography (CTA) readings. We aim to evaluate the impact of consistently including CT perfusion (CTP) in admission stroke imaging protocols.MethodsFrom April to October 2020 all patients admitted with a suspected acute ischemic stroke underwent urgent non-contrast CT, CTA and CTP and were treated accordingly. Hypoperfusion areas defined by time-to-maximum of the tissue residue function (Tmax) >6 s, congruent with the clinical symptoms and a vascular territory, were considered VO (CTP-VO). In addition, two experienced neuroradiologists blinded to CTP but not to clinical symptoms retrospectively evaluated non-contrast CT and CTA to identify intracranial VO (CTA-VO).ResultsOf the 338 patients included in the analysis, 157 (46.5%) presented with CTP-VO (median Tmax >6s: 73 (29–127) mL). CTA-VO was identified in 83 (24.5%) of the cases. Overall CTA-VO sensitivity for the detection of CTP-VO was 50.3% and specificity was 97.8%. Higher hypoperfusion volume was associated with increased CTA-VO detection (OR 1.03; 95% CI 1.02 to 1.04). EVT was performed in 103 patients (30.5%; Tmax >6s: 102 (63–160) mL), representing 65.6% of all CTP-VO. Overall CTA-VO sensitivity for the detection of EVT-VO was 69.9% and specificity was 95.3%. Among patients who received EVT, the rate of false negative CTA-VO was 30.1% (Tmax >6s: 69 (46–99.5) mL).ConclusionSystematically including CTP in acute stroke admission imaging protocols may increase the diagnosis of VO and rate of EVT.

Cost-effectiveness of CT perfusion for the detection of large vessel occlusion acute ischemic stroke followed by endovascular treatment: A model-based health economic evaluation study

“…The value of CTP-based screening might be higher for physicians with less experience in neuroimaging assessments. In this study we reported a wide variety of sensitivity differences as the current evidence comparing NCCT+CTA+CTP with NCCT+CTA based LVO detection is limited by a small sample size and suboptimal research designs (1)(2)(3)(4). Third, we used conservative ORs for the EVT treatment effect based on the MR CLEAN trial (12).…”

“…Brain tissue perfusion maps derived from computed tomography perfusion (CTP) have been suggested to improve occlusion detection in acute ischemic stroke (AIS) patients if used in addition to CT angiography (CTA) and non-contrast CT (NCCT) (1)(2)(3)(4). Although CTP is primarily considered to select patients for endovascular treatment (EVT) (5), screening all suspected AIS patients presenting within six hours after symptom onset with CTP could also enhance the detection of patients with a large vessel occlusion (LVO) EVT; resulting in more patients who benefit from EVT and less missed occlusions (6).…”

Commentary on ‘Systematic CT perfusion acquisition in acute stroke increases vascular occlusion detection and thrombectomy rates’

“…An important finding of Olive-Gadea et al is that the likelihood of identifying a vessel occlusion on CTA alone was under 50% for hypoperfusion volumes (Tmax >6 s) less than 90 mL, whereas the probability of undergoing EVT in these patients was 88.4% 1. This is surprising, because given that the patient has such a high probability of undergoing EVT, one would expect a high likelihood of identifying a vessel occlusion on CTA.…”

“…In their JNIS study, Olive-Gadea et al present a retrospective single-center study demonstrating that inclusion of systematic CT perfusion (CTP) in acute stroke imaging protocols improves the detection of intracranial vessel occlusions and helps to identify additional endovascular treatment (EVT) candidates compared with using CT angiography (CTA) alone 1. Their sample group consisted of 338 consecutive patients with suspected acute ischemic stroke who underwent urgent non-contrast CT, CTA, and CTP.…”

“…This is surprising, because given that the patient has such a high probability of undergoing EVT, one would expect a high likelihood of identifying a vessel occlusion on CTA. Interestingly, they found that a hypoperfusion volume (Tmax >6 s) cut-off point greater than 13 mL predicted an indication for EVT with a sensitivity of 99% and a specificity of 87.2% 1…”