Transient global amnesia: Signal alteration in 2D/3D T2-FLAIR sequences

• Published in: Clinical imaging Vol. 78; pp. 154 - 159
• Main Authors: You, Sung-Hye, Kim, Byungjun, Kim, Bo Kyu
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.10.2021; Elsevier Limited
• Subjects: Age; Amnesia; Amnesia, transient global; Diffusion magnetic resonance imaging; Hippocampus; Ischemia; Lesions; Magnetic resonance imaging; Medical imaging; Neurology; Patients; Sequences; Amnesia, transient global; Magnetic resonance imaging; Ischemia; Diffusion magnetic resonance imaging; CA; TGA
• ISSN: 0899-7071; 1873-4499
• DOI: 10.1016/j.clinimag.2021.03.029

Transient global amnesia (TGA) is one of the most enigmatic syndromes in clinical neurology. The detection rate of TGA lesions in 2D/3D FLAIR sequences has not been evaluated. A total of 201 patients (44 men and 157 women; mean age, 60.34 ± 9.23 years; range, 22–91 years) diagnosed with TGA, who underwent diffusion-weighted imaging (DWI; b = 1000 s/mm2, b = 2000 s/mm2, 4 mm) and/or 2D/3D-FLAIR sequences (4 mm, 0.9 mm; respectively) using 3-T MRI within 28 days after onset of TGA symptoms, were included in this single-center, retrospective, cross-sectional study. Hippocampal lesions were visually assessed in all sequences and detection rates were analyzed according to imaging timing (1 day, 2–4 days, 5–7 days, 8–11 days, and 12–28 days) and kinds of sequences. The detection rates were highest 2–4 days after symptom onset in all sequences, and that was higher in order of b = 2000 (75.28% [67/89]), b = 1000 (63.92% [62/97]), 3D-FLAIR (59.38% [19/32]), and 2D-FLAIR (15.15% [15/99]). On FLAIR sequences, detectability was lower 5–7 days after onset than that 2–4 days after onset (2D-FLAIR, 15.15% [15/99] vs. 5.56% [1/18]; 3D-FLAIR, 59.38% [19/32] vs. 0.00% [0/1]). FLAIR signal changes occur in approximately 60% of TGA patients 2–4 days after symptom onset, and decrease after 5 days. It is postulated that the pathophysiology of TGA might differ from common ischemic changes. •The imaging finding of TGA on the T2-FLAIR image was not negative.•The detection rates of TGA lesion on 2D and 3D FLAIR images were 15% and 60% at days 2–4, and they decreased on days 5–7.•This signal alteration pattern differs from arterial ischemia and coincide more with the focal energy failure mechanism.