Signal Intensity Gradient in Cerebral Arteries

Study Overview
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Brief Summary
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Arterial wall shear stress (WSS) contributes to atherosclerosis from its inception, progression, and disruption of plaque. However, there is no previous study for an association between cerebral artery WSS and clinical outcome in patients with ischemic stroke in lenticulostriate artery. The researchers aimed to investigate whether the signal intensity gradient (SIG) from Time-of-Flight Magnetic Resonance Angiography (TOF MRA) in cerebral arteries, as a surrogate measure of arterial WSS, is associated with clinical outcome, which was determined with modified Rankin Scale (mRS). The patients (n=294) with the lenticulostriate artery infarction were collected in 3 hospitals with variable locations and sizes (Gunsan, Jeonju, and Seoul). For a clinical outcome, National Institute of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) were checked serially from the date of admission. The mRS 2 or less at the 7th day or discharge was defined as a favorable outcome. The arterial SIGs were measured concurrently in both internal carotid, anterior/middle/posterior cerebral, vertebral arteries, and basilar artery from TOF MRA on initial diagnosis. The independent association between the clinical outcome and cerebral arterial SIG was analyzed adjusting for all the possible potential confounders.

Official Title
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Association Between Signal Intensity Gradient of Cerebral Arteries From Time-of-flight Magnetic Resonance Angiography and Clinical Outcome in Patients With Lenticulostriate Artery Infarction

Conditions
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Ischemic Stroke, Acute

Intervention / Treatment
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* Diagnostic Test: Signal intensity gradient


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients aged 18 years or older who had brain magnetic resonance imaging (MRI) for acute ischemic stroke within 3 days Patients who underwent diffusion-weighted imaging (DWI) and apparent diffusion coefficient of the cerebral parenchyma, and cerebral angiographic measurements, in which, intracranial arteries should be examined by time-of-flight (TOF) techniques A patient with high signal intensity lesions in the unilateral LSA territory on DWI. Exclusion Criteria: Patients younger than 18 years of age Patients with moderate to severe (>50%) stenosis or occlusion of the major intracranial and extracranial arteries, including internal carotid artery (ICA), middle cerebral artery (MCA), anterior cerebral artery (ACA), posterior cerebral artery (PCA), basilar artery (BA), and vertebral artery (VA) Patients whose ischemic stroke was due to or related with cardiac or rare etiology (e.g., arterial dissection, moyamoya disease).

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Grouped as the favorable outcome<br><3 mRS of discharge or 7th day in the patients with the lenticulostriate artery infarction | Diagnostic Test: Signal intensity gradient<br>* In time-of-flight (TOF) MRA, The signal intensities at the iso-point (Φa; signal intensity at position A [Xa] along the arterial contour line) and at the inner point (Φb; signal intensity at position B [Xb]) were calculated by using a trilinear interpolation algorithm based on the positions and signal intensities in the eight neighboring voxels. The signal intensities of TOF-MRA were normalized to eliminate the offset and scale effects across the MRA datasets of participants. For each iso-point (position A), the SIG was calculated from the difference in signal intensities between points A and B as follows: Scalar SIG, SI/mm = (Φb - Φa) / │Xb - Xa│ (1) Vector SIG, SI/mm = (Φb - Φa) n / │Xb - Xa│ (2)<br>|
| Grouped as the unfavorable outcome<br>≥3 mRS of discharge or 7th day in the patients with the lenticulostriate artery infarction | Diagnostic Test: Signal intensity gradient<br>* In time-of-flight (TOF) MRA, The signal intensities at the iso-point (Φa; signal intensity at position A [Xa] along the arterial contour line) and at the inner point (Φb; signal intensity at position B [Xb]) were calculated by using a trilinear interpolation algorithm based on the positions and signal intensities in the eight neighboring voxels. The signal intensities of TOF-MRA were normalized to eliminate the offset and scale effects across the MRA datasets of participants. For each iso-point (position A), the SIG was calculated from the difference in signal intensities between points A and B as follows: Scalar SIG, SI/mm = (Φb - Φa) / │Xb - Xa│ (1) Vector SIG, SI/mm = (Φb - Φa) n / │Xb - Xa│ (2)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change of signal intensity gradient at discharge or 7th day in the patients with the lenticulostriate artery infarction | Degrees of the signal intensity gradient (SIG) from brain TOF-MRA in major cerebral arteries are measured in the patients with the lenticulostriate artery infarction at discharge or 7th day. | Approximately 1 week | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Cerebral artery, Lenticulostriate artery infarction, Signal intensity gradient, Signal intensity gradient, Wall shear stress