Influence of Hematocrit Level on the Visibility of the Venous Network in Magnetic Susceptibility Imaging

N/AUnknownNCT05192135

Fondation Hôpital Saint-Joseph65 enrolled

Overview

Magnetic susceptibility imaging is a magnetic resonance imaging (MRI) technique that uses the magnetic properties of tissues and the BOLD (blood oxygen level-dependent) effect. It allows a better visualization of venous structures and hemorrhagic lesions. These sequences are now used in clinical routine. The extreme sensitivity of these sequences to the oxy/deoxyhemoglobin ratio makes it possible to describe a new MRI semiology, particularly in the context of cerebral ischemia. The interest of the analysis of the venous network signal, which can reflect cerebral perfusion, has been reported. However, the influence of the hematocrit level on the signal of the venous network in magnetic susceptibility imaging has not been evaluated at present. It seems important to better define the influence of hematocrit level on the signal of the veins with this sequence to avoid potential diagnostic errors.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Stroke

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Patient whose age ≥ 18 years * Patient referred to GHPSJ for suspected stroke * Patient who had a brain MRI including the magnetic susceptibility sequence * Patient for whom a blood count with hematocrit was performed at the same time (within 7 days between the MRI and the blood test) * French-speaking patient Exclusion Criteria: * Patient under guardianship or curatorship * Patient deprived of liberty * Patient under court protection * Elimination of potential biases: recent injection (48 h) of gadolinium, pathology likely to modify the venous signal in magnetic susceptibility imaging (notably arterial occlusion or stenosis), high flow oxygenation, sickle cell disease, thalassemia. * Patient objecting to the use of his/her data for this research

Outcomes

Primary Outcomes

Specific influence of the hematocrit level on the visibility of the venous network

This outcome corresponds to the visibility of the venous network in magnetic susceptibility imaging using a visual scale allowing comparison between patients with normal hematocrit, anemia or polycythemia.

Time frame: Day 1

Secondary Outcomes

Inter-observer agreement of the visual analysis of the venous network

This outcome corresponds to the correlation of visual scales between different observers.