Tmax Mismatch Ratio to Identify Intracranial Atherosclerotic Stenosis‐Related Large‐Vessel Occlusion Before Endovascular Therapy

Abstract

Background We aimed to clarify which time‐to‐maximum of the tissue residue function (Tmax) mismatch ratio is useful in predicting anterior intracranial atherosclerotic stenosis (ICAS)–related large‐vessel occlusion (LVO) before endovascular therapy. Methods and Results Patients with ischemic stroke who underwent perfusion‐weighted imaging before endovascular therapy for anterior intracranial LVO were divided into those with ICAS‐related LVO and those with embolic LVO. Tmax ratios of >10 s/>8 s, >10 s/>6 s, >10 s/>4 s, >8 s/>6 s, >8 s/>4 s, and >6 s/>4 s were considered Tmax mismatch ratios. Binominal logistic regression was used to identify ICAS‐related LVO, and the adjusted odds ratio (aOR) and 95% CI for each Tmax mismatch ratio increase of 0.1 were calculated. A similar analysis was performed for ICAS‐related LVO with and without embolic sources, using embolic LVO as the reference. Of 213 patients (90 women [42.0%]; median age, 79 years), 39 (18.3%) had ICAS‐related LVO. The aOR (95% CI) per 0.1 increase in Tmax mismatch ratio in ICAS‐related LVO with embolic LVO as reference was lowest with Tmax mismatch ratio >10 s/>6 s (0.56 [0.43–0.73]). Multinomial logistic regression analysis also showed the lowest aOR (95% CI) per 0.1 increase in Tmax mismatch ratio with Tmax >10 s/>6 s (ICAS‐related LVO without embolic source: 0.60 [0.42–0.85]; ICAS‐related LVO with embolic source: 0.55 [0.38–0.79]). Conclusions A Tmax mismatch ratio of >10 s/>6 s was the optimal predictor of ICAS‐related LVO compared with other Tmax profiles, with or without an embolic source before endovascular therapy. Registration clinicaltrials.gov . Identifier NCT02251665.

Patchy profile sign in RAPID software: a specific marker for intracranial atherosclerotic stenosis in acute ischemic stroke

“…The study found that ICAS-related LVO had smaller areas of hypoperfusion compared to embolization-related LVO, which is consistent with prior investigations ( 22 , 32 ). Contrary to embolization-related LVO, EVT for ICAS-related LVO is associated with a higher incidence of intraoperative reocclusion, an extended operating time, elevated mortality rates, and reduced revascularization rates ( 33 ).…”

Emergent Large Vessel Occlusion due to Intracranial Stenosis: Identification, Management, Challenges, and Future Directions

“…Owing to robust collaterals, patients with ICAS-LVO are more likely to present with fluctuating symptoms and lower stroke severity compared with embolic LVO patients. 56,57 While the diagnosis of ICAS-LVO is commonly made intraprocedurally, some preprocedural imaging findings are important to evaluate and could help in establishing early diagnosis. On noncontrast computed tomography scan, the presence of calcification could be suggestive of ICAS.…”

“…The investigators found that a lower Tmax mismatch ratio of >10 seconds/>6 seconds (indicative of good collaterals) to be the optimal predictor of ICAS-LVO. 56 Finally, a number of studies attempted to provide prediction models to identify ICAS-LVO; however, most studies have modest sensitivity and specificity. [61][62][63][64] In a posthoc analysis of the DIRECT-MT trial (Endovascular Thrombectomy With or Without Intravenous Alteplase in Acute Stroke), the investigators created a predictive model for early diagnosis of ICAS-LVO, 65 which included the presence of atrial fibrillation history, hyperdense sign, and M2 occlusion to be negatively correlated with ICAS-LVO whereas the presence of hypertension, smoking, lower clot burden score, and occlusion of the M1.…”

“…Owing to robust collaterals, patients with ICAS-LVO are more likely to present with fluctuating symptoms and lower stroke severity compared with embolic LVO patients. 56,57…”

Clinico-radiological features of intracranial atherosclerosis-related large vessel occlusion prior to endovascular treatment

“…However, the diagnostic performance of clinical and radiological biomarkers to detect underlying ICAD before EVT has not been systematically studied. Previous studies suggest that automated parameters of computed tomography perfusion (CTP) associated with a good collateral status are associated with underlying ICAD 5 – 9 .…”