HIR and Tmax mismatch ratios were associated with acute steno-occlusive ICA due to atherosclerotic disease before EVT, suggesting perfusion imaging may facilitate early identification of underlying etiology to enable a more tailored cervical approach during endovascular treatment.
Key Findings
Results
Patients with atherosclerotic ICA lesions had significantly lower median volumes of CBF <20% compared to nonatherosclerotic cases.
Median CBF <20% volume was 0 mL in atherosclerotic cases versus 4 mL in nonatherosclerotic cases.
The study included 78 patients who met inclusion criteria, of whom 53 (67.9%) had atherosclerotic ICA lesions.
All patients had ≥70% extracranial ICA stenosis and underwent CT perfusion imaging prior to EVT.
Patients were drawn from a retrospective cohort of 622 consecutive EVT stroke patients from January 2019 to December 2022.
Results
Atherosclerotic ICA lesions were associated with significantly lower hypoperfusion intensity ratio (HIR) compared to nonatherosclerotic cases.
Median HIR was 0.27 in atherosclerotic cases versus 0.47 in nonatherosclerotic cases (P < .01).
In multivariable logistic regression, lower HIR was independently associated with atherosclerotic ICA disease (adjusted OR 0.01; 95% CI: 0.00–0.16).
HIR is a perfusion parameter reflecting collateral status in patients with acute ischemic stroke due to anterior large-vessel occlusion.
The lower HIR in atherosclerotic cases suggests better collateral flow, potentially reflecting chronic adaptation to stenosis.
Results
Multiple Tmax mismatch ratios were independently associated with atherosclerotic ICA lesions in multivariable analysis.
All four Tmax mismatch ratios showed reduced values in atherosclerotic compared to nonatherosclerotic cases.
Methods
The study population had a median age of 68 years with a moderate-to-severe stroke severity at presentation.
Median age was 68 years (IQR 60–76); 39.7% were women.
Median NIHSS score was 15 (IQR 10–18), indicating moderate-to-severe stroke.
Of 622 patients who underwent EVT, 78 met inclusion criteria (≥70% extracranial ICA stenosis with CT perfusion imaging).
Patients were categorized into atherosclerotic (n=53, 67.9%) and nonatherosclerotic (n=25, 32.1%) groups based on clinical and radiologic characteristics.
Discussion
Perfusion imaging parameters, particularly HIR and Tmax mismatch ratios, may help identify the etiology of extracranial ICA lesions before endovascular therapy.
The role of perfusion imaging in identifying etiology of extracranial ICA lesions before EVT was previously underexplored.
Early identification of atherosclerotic versus nonatherosclerotic etiology 'may facilitate a more tailored cervical approach during endovascular treatment.'
CBF, CBV, time-to-maximum (Tmax), and Tmax mismatch ratios were all compared between groups.
The study design was a retrospective single-institution cohort, which limits generalizability.
What This Means
This research suggests that CT perfusion imaging — a type of brain scan commonly used during stroke evaluation — can provide clues about the underlying cause of a blockage in the carotid artery (the main artery supplying blood to the brain) before doctors begin endovascular treatment (a procedure to physically remove or open the blockage). Specifically, the study found that two perfusion measurements — the hypoperfusion intensity ratio (HIR) and certain Tmax mismatch ratios — were significantly lower in patients whose carotid artery blockage was caused by atherosclerosis (hardening of the arteries from plaque buildup) compared to those with other causes. Among 78 stroke patients who had severe carotid artery narrowing and received endovascular therapy, about 68% had atherosclerotic disease, and these patients showed distinctly different perfusion patterns on their brain scans.
This matters because the treatment approach for carotid artery blockages caused by atherosclerosis may differ from other causes — for example, atherosclerotic lesions may require special techniques like angioplasty or stenting during the endovascular procedure. Currently, doctors often cannot determine the exact cause of the blockage until they are already performing the procedure. This research suggests that analyzing perfusion imaging data collected before the procedure could give physicians earlier insight into what type of lesion they are likely to encounter, potentially allowing them to better plan and tailor their approach.
The study was retrospective (looking back at existing records) and conducted at a single institution with a relatively small sample of 78 patients, so further research with larger and more diverse populations would be needed to confirm these findings. Nevertheless, the results highlight a potentially valuable and previously underexplored use of routine perfusion imaging in acute stroke care.
Quispe-Orozco D, Galecio-Castillo M, Cruz-Criollo L, Abdelhakim N, Brito A, Kontowicz E, et al.. (2026). Perfusion Parameters to Identify Acute Steno-occlusive Carotid Artery Disease Due to Atherosclerosis Prior to Endovascular Therapy.. AJNR. American journal of neuroradiology. https://doi.org/10.3174/ajnr.A9156