Optimization of magnetic resonance imaging protocol for the diagnosis of transient global amnesia

Abstract

Objective: To emphasize the most appropriate magnetic resonance imaging (MRI) diffusion protocol for the detection of lesions that cause transient global amnesia, in order to perform an accurate examination, as well as to determine the ideal time point after the onset of symptoms to perform the examination. Materials and Methods: We evaluated five patients with a diagnosis of transient global amnesia treated between 2012 and 2015. We analyzed demographic characteristics, clinical data, symptom onset, diffusion techniques, and radiological findings. Examination techniques included a standard diffusion sequence (b value = 1000 s/mm2; slice thickness = 5 mm) and a optimized diffusion sequence (b value = 2000 s/mm2; slice thickness = 3 mm). Results: Brain MRI was performed at 24 h or 36 h after symptom onset, except in one patient, in whom it was performed at 12 h after (at which point no changes were seen) and repeated at 36 h after symptom onset (at which point it showed alterations in the right hippocampus). The standard and optimized diffusion sequences were both able to demonstrate focal changes in the hippocampi in all of the patients but one, in whom the changes were demonstrated only in the optimized sequence. Conclusion: MRI can confirm a clinical hypothesis of transient global amnesia. Knowledge of the optimal diffusion parameters and the ideal timing of diffusion-weighted imaging (> 24 h after symptom onset) are essential to improving diagnostic efficiency.

Sensitivity of diffusion‐weighted magnetic resonance imaging in transient global amnesia as a function of time from symptom onset

“…After screening the titles and abstracts, we identified 81 potentially relevant studies. After full‐text review, 23 studies with a total of 1,688 subjects met inclusion criteria 7,10–31 . All studies were case series of adult patients clinically diagnosed with acute TGA who underwent DW‐MRI.…”

Posterior cingulate gyri metabolic alterations in HIV-positive patients with and without memory deficits

“…Recent studies conducted in Brazil have highlighted the importance of imaging methods in the evaluation of diseases affecting the central nervous system (24)(25)(26)(27)(28)(29) . Spectroscopy in the posterior cingulate gyrus is extensively studied in Alzheimer's disease, in which previous studies showed lower NAA/Cr ratio in patients with Alzheimer's disease than in individuals with mild cognitive impairment and controls.…”

Two Patients With Transient Global Amnesia in Which Repeated Diffusion-Weighted Imaging Revealed Hippocampal Hyperintensity: Case Reports

“…Diffusion-weighted magnetic resonance imaging (DW-MRI) can usually help to detect the lesions in the brain. In early stages of TGA, a DW-MRI may not generate any findings so the MRI may need to be repeated (1). We present two patients in which DW-MRI revealed hip-pocampal lesions because the detection of these lesions changes the treatment strategies.…”