7T-TGA - High-resolution MRI imaging in TGA patients: a retrospective and prospective study

In transient global amnesia (TGA), the patients affected suffer from a disorder of the anterograde and also of the retrograde memory, so that what has been newly learned or experienced is not memorized. Classically, patients become conspicuous by asking repetitive questions about location and situation. The duration of the acute phase is usually between 4-8 hours, after 24 hours the symptoms are regredient and there is an amnesty gap.

TGA is reported in systematic epidemiological studies with an incidence of approx. 3-8/100,000 inhabitants, 75% of the affected patients being between 50 and 70 years old. Typically, amnesia is preceded by an episode of physical and psychological tension. The underlying pathophysiology of TGA remains unclear. In the past a broad spectrum of different causes have been discussed and investigated, including ischemia, epileptic seizures, migraine attacks and venous congestion, without clear clarification.
Before the availability of high-resolution MRI imaging, no proof of a structural cause had been possible. In recent years, it has been possible to demonstrate structural lesions in the hippocampus in the CA1 region due to the higher resolution, finer stratification and optimization of the measurement timing after the event.

The aim of this study is to use ultra-high-resolution MRI images (7-Tesla) to obtain a more precise classification of the aforementioned lesions in the hippocampus and possibly other extrachippocampal lesions and to correlate them with the neuropsychological test results.

Patients who have already experienced a TGA episode in the past will undergo a high-resolution MRI examination and neuropsychological testing.
In addition, in the prospective group, we will examine patients within 24-72 hours after an acute TGA episode, 30 days and 1 year in MRI and neuropsychology to assess acute lesions and their progression.

Principle Investigator: Prof. Dr. Gabor Petzold
Start of the study: 2015
Status: monocentric (DZNE Bonn), retrospective and prospective study