Longitudinal Monitoring of Cerebral Connectivity 3T MRI in Patients With a Transcient Global Amnesia

Summary

The transient global amnesia (IA) is defined clinically as a temporary suspension and isolated from the ante and retrograde memory, totally regressing within 24 hours. The causes of AI remain unknown. The diagnosis of IA is based on consensus clinical criteria including the absence of associated location marks. In clinical practice, the MRI is often performed in conjunction with clinical examination because it ensures the absence of differential diagnoses, including stroke.

The visualization of MRI signal abnormalities related to AI directly dependent on the completion time of the review in relation to the onset of symptoms. Typically, no signal abnormality is visible in the hyperacute phase (ie D0-D1) while punctate appear hyperintense on diffusion sequences in hippocampal structures from J2 to J7 to disappear completely. It has been previously demonstrated that the use of higher values of b and / or a better spatial resolution significantly increases the sensitivity of the broadcasting sequence for the detection of these abnormalities hippocampal signal. At St. Joseph Hospital, Investigators explore the AI suspected patients with diffusion tensor sequence (DTI) on our high resolution 3T MRI.

Compared to the classical diffusion sequence, DTI is characterized by the use of a greater number of directions in which the diffusion gradients are applied. One advantage of this technique is to be able to perform tractography of white matter fibers. Thus the "connectome" is a new technique for post-processing of DTI images based tractography and to assess all the networks of nerve fibers in the brain. By this technique, the values of average diffusivity (MD) and fractional anisotropy (FA) can be measured along each of the studied nerve fibers. Group studies thus become feasible to compare quantitatively healthy subjects and patients groups in terms of structural differences within the connectome. The contribution of this technique was recently highlighted in patients with temporal lobe epilepsy.

Conditions

• Amnesia

Interventions

PROCEDURE

achieving a neuropsychological examination in the acute amnesic phase

achieving a neuropsychological examination in the acute phase in addition to the normal protocole

PROCEDURE

Neurological consultation with neuropsychological evaluation

Neurological consultation with neuropsychological evaluation one year after the acute amnesic phase

RADIATION

MRI

Brain MRI with the same protocol or an acquisition time of 15 minutes without gadolinium, one year after the acute amesic phase

Sponsors & Collaborators

• Fondation Hôpital Saint-Joseph

  lead OTHER

Principal Investigators

• Jerome HODEL, MD · Fondation Hôpital Saint-Joseph

Study Design

Allocation

NA

Purpose

BASIC_SCIENCE

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2015-09-02

Primary Completion

2018-12-31

Completion

2018-12-31

Countries

• France

Study Locations