Characteristics of Signal Intensity Gradient in Subarachnoid Hemorrhage After Aneurysmal Rupture

Study Overview
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Brief Summary
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10-20% of patients with subarachnoid hemorrhage die before they arrive at the hospital, and about 25% die within 24 hours. About 1% of patients are diagnosed with cerebral aneurysms in imaging tests for health checkups, and many of them experience aneurysmal rupture during their lifetime, so it is not a rare disease. Wall shear stress is known to be a factor that reflects the state of blood vessels, and particularly plays an important role in the patency of the intima of blood vessels. In the meantime, computed fluid dynamics (CFD), a representative method for calculating wall shear stress, assumes a virtual rigid pipe and applies a preset value. This does not accurately reflect the physiological and dynamic state of the actual blood vessel. The investigators intend to measure the patient's wall shear stress using the SIG of the MRA-TOF technique, which reflects the physiological characteristics of individual patients, and to analyze the association with rupture of the intracranial aneurysm.

Official Title
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Analysis of Hemodynamic Characteristics Using Signal Intensity Gradient of Brain Magnetic Resonance Imaging in Patients With Subarachnoid Hemorrhage After Rupture of Intracranial Aneurysm

Conditions
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Aneurysmal Rupture

Intervention / Treatment
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* Diagnostic Test: Signal intensity gradient


Participation Criteria
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Eligibility Criteria
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<Ruptured group> Inclusion Criteria: 1) Patients over 18 years of age who visited our hospital for acute subarachnoid hemorrhage due to rupture of a intracranial aneurysm (2) Among patients satisfying (1), who had intracranial magnetic resonance imaging (time-of-flight (TOF) technique applied; diffusion-weighted imaging, including apparent diffusion coefficient) before subarachnoid hemorrhage occurred. Exclusion Criteria: Patients under the age of 18 Patients with subarachnoid hemorrhage due to causes other than rupture of intracranial aneurysm Patients with poor imaging quality due to artifacts caused by patient movement during brain magnetic resonance imaging examination <Unruptured group> Inclusion Criteria: Magnetic resonance imaging performed during the screening period (Time-of-Flight (TOF) technique is applied to intracranial vessel imaging; It also includes diffusion-weighted imaging and apparent diffusion coefficient) Patients diagnosed with unruptured intracranial aneurysm in the final reading of brain MR test Patients who remain without aneurysmal rupture on follow-up intracranial magnetic resonance imaging Exclusion Criteria: Patients under the age of 18 Patients with poor imaging quality due to artifacts caused by patient movement during brain magnetic resonance imaging examination

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 |
| --- | --- |
| Ruptured group<br>Group of subarachnoid hemorrhage after rupture of intracranial aneurysm | 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>|
| Unruptured group<br>Group of inexperience of aneurysmal rupture during specific period | 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 |
| --- | --- | --- |
| Degree of signal intensity gradient in aneurysmal sac | The investigators will measure the degree of signal intensity gradient (SIG) from brain TOF-MRA in aneurysmal sac. The measured SIG in ruptured group would be lower than that in unruptured group. | Average 4-6 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Signal intensity gradient, Wall shear stress, Aneurysmal rupture, Time-of-Flight MRI