Optimal Diffusion-Weighted Imaging Protocol for Lesion Detection in Transient Global Amnesia

Abstract

BACKGROUND AND PURPOSE: Diffusion-weighted imaging (DWI) can depict small punctate hyperintense lesions in the hippocampus in transient global amnesia (TGA). The purpose of this study was to find an optimal DWI protocol for lesion detection in TGA by investigating various imaging parameters and imaging timing after symptom onset.

CTP in Transient Global Amnesia: A Single-Center Experience of 30 Patients

“…1,2,14 We hypothesize that disruption of the corticohippocampal circuitry without direct involvement of the mesiotemporal region may have caused a clinical syndrome indistinguishable from classic TGA. In both SPECT and PET studies, perfusion abnormalities in the basal ganglia have been reported for TGA but were associated with concomitant medial temporal lobe hypoperfusion.…”

High-Resolution Diffusion-Weighted Imaging Increases Lesion Detectability in Patients with Transient Global Amnesia

“…However, previous studies reported relatively lower incidence of multiplicity, ranging from 5% to 38%. 7,10,22,23 This may be due to increased detectability of high-resolution DWI for smaller lesions, which were missed on lower resolution by partial volume averaging effects. 7,9,22 Therefore, we think that high-resolution DWI with less partial volume averaging might improve lesion contrast in our study.…”

“…High b-value (ie, 2000 -3000 seconds/mm 2 ), thin section thickness (ie, 3 mm), and imaging 48 -72 hours after the onset of symptoms increased lesion detectability of DWI. 7,10,18 However, until now, there has been no well-designed study to evaluate the influence of the resolution of DWI on lesion detectability in TGA. In this study, we investigated whether punctuate TGA lesions can be detected more often by increasing the resolution of DWI.…”

“…[2][3][4][5] Many recent studies have reported that 1-to 5-mm punctuate high-signal intensity lesions have frequently been found in the lateral portion of the hippocampus, that is, the CA1 region, on DWI in TGA. [6][7][8][9][10][11] Although imaging detection of the lesions in TGA may not change the clinical course of this self-resolving disorder or affect treatment planning, an optimal DWI protocol may help to exclude other possible urgent differential diagnoses that might clinically mimic the symptoms of TGA, such as transient ischemic attack, seizure, drug-induced amnesia, and other causes of altered awareness. [12][13][14][15] The detection rate of TGA lesions on DWI has been reported as a wide range between 0%-84%.…”

“…[12][13][14][15] The detection rate of TGA lesions on DWI has been reported as a wide range between 0%-84%. 6,7,10,16,17 These variable rates of lesion detection are attributable to different imaging parameters such as section thickness, b-value, and imaging timing from the onset of symptoms. High b-value (ie, 2000 -3000 seconds/mm 2 ), thin section thickness (ie, 3 mm), and imaging 48 -72 hours after the onset of symptoms increased lesion detectability of DWI.…”