Transient global amnesia: Diffusion MRI findings

Tarun P Jain; Ronak Patel; Yash Gawarikar

doi:10.4103/ijri.IJRI_12_17

Indian Journal of Radiology and Imaging, Table of Contents

CC BY-NC-ND 4.0 · Indian J Radiol Imaging 2018; 28(01): 6-9
DOI: 10.4103/ijri.IJRI_12_17

Neuroradiology & Head and Neck Imaging

Transient global amnesia: Diffusion MRI findings

Authors

Tarun P Jain

Universal Medical Imaging, Canberra
Ronak Patel

Stroke Service, Calvary Public Hospital, Bruce
Yash Gawarikar

Stroke Service, Calvary Public Hospital, Bruce

Australian National University, Canberra, ACT, Australia

Subject Editor:

Abstract

Introduction: Aim of this study is to identify and describe the MRI findings in patients with Transient Global Amnesia (TGA), specifically on Diffusion Weighted Imaging (DWI) sequence. Methods: MRI findings in 12 patients with clinical diagnosis of TGA were retrospectively analysed. MRI brain was performed with a 3T scanner on 11 patients and 1.5T scanner on 1 patient. DWI were acquired at B value of 1000 s/mm² in 4 patients, 2000 s/mm² in 2 patients and both 1000 and 2000 s/mm² in 6 patients. Results: There were 7 female and 5 male patients. The mean age was 65.67 years (range 61-74 years). The median time interval between the onset of symptom and MRI scan was 47.5 hours, range 25-114 hours. 11 of the 12 patients showed punctate foci of restricted diffusion in hippocampus (mean size 3.7 mm (range 2-6.5 mm). 10 patients showed foci in left hippocampus. Nine patients showed a single focus, 1 patient showed three foci and 1 patient showed four foci. In 6 patients who had DWI MRI at both B values, scans at B value of 1000 s/mm² revealed abnormality in 4 patients, while higher B value imaging improved sensitivity in one patient and one patient had a negative scan at both B values. Conclusion: We have highlighted the MRI finding of typical punctate foci of bright signal in hippocampus seen on DWI in patients diagnosed with TGA. Detection on a routine stroke MRI protocol can avoid need for dedicated TGA protocols or repeat scan, improving the workflow.

Keywords

Amnesia - diffusion MRI - transient global amnesia - hippocampus - neuroimaging

Full Text

References

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