Detection of delayed focal MR changes in the lateral hippocampus in transient global amnesia

Abstract

The study confirms the involvement of hippocampal parenchyma in the pathophysiology of TGA. The delayed detectability of the lesions may explain the incongruence of previous MR DWI studies in TGA patients.

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

“…This result concurred with the study by Sedlaczek et al, 9 in which the lesion-detection rate was 6% within 8 hours of onset and increased up to 84% at 48 hours after onset. The pathogenesis of TGA is uncertain, and various etiologic hypotheses have been proposed, including thromboembolism, 9,10 cerebral venous congestion induced by Valsalva-like activities, [18][19][20] and vasoconstriction caused by hyperventilation. 21 Whatever its etiology, several authors have suggested that delayed neuronal injury in the hippocampus is the cause of the delayed appearance of the lesions on DWI.…”

“…6 Recent diffusion-weighted imaging (DWI) studies have indicated the presence of focal hyperintensities involving the hippocampus in TGA. [7][8][9][10][11] The lesions detected by DWI are small and punctate (1-3 mm) and located within the lateral portion of the hippocampus. 9,11,12 Since Strupp et al 13 first detected hyperintense lesions in the hippocampus in TGA by using DWI, the frequency of lesions detected on DWI has been reported in a range of 0%-84%.…”

“…[7][8][9][10][11] The lesions detected by DWI are small and punctate (1-3 mm) and located within the lateral portion of the hippocampus. 9,11,12 Since Strupp et al 13 first detected hyperintense lesions in the hippocampus in TGA by using DWI, the frequency of lesions detected on DWI has been reported in a range of 0%-84%. 9,10,14,15 According to a recent study, this discrepancy in detection rates appears to be attributable to the different timing of imaging from the onset of symptoms.…”

“…9,11,12 Since Strupp et al 13 first detected hyperintense lesions in the hippocampus in TGA by using DWI, the frequency of lesions detected on DWI has been reported in a range of 0%-84%. 9,10,14,15 According to a recent study, this discrepancy in detection rates appears to be attributable to the different timing of imaging from the onset of symptoms. 9 In this previous study, a detection rate of only 6% by DWI was achieved within several hours of symptom onset, but this increased up to 84% at 48 hours post-symptom onset.…”

“…9,10,14,15 According to a recent study, this discrepancy in detection rates appears to be attributable to the different timing of imaging from the onset of symptoms. 9 In this previous study, a detection rate of only 6% by DWI was achieved within several hours of symptom onset, but this increased up to 84% at 48 hours post-symptom onset.…”