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

American Journal of Neuroradiology

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Fig 1.
A 49-year-old woman (patient 8) with TGA. A, Initial DWIs obtained at 11 hours 15 minutes after the onset of symptoms show no lesion at b = 1000/5 mm, but a subtle bright lesion in the right hippocampal body (arrows) at b = 1000/3 mm, b = 2000/3 mm, and b = 3000/3 mm, with increasing lesion conspicuity by increasing the b-value. B, Follow-up DWIs after 3 days show a much brighter lesion (arrows) in all sequences.
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Fig 2.
A 50-year-old woman (patient 3) with TGA. All initial DWIs (A) obtained at 4 hours 30 minutes after the onset of symptoms and follow-up DWIs (B) after 3 days at b = 1000/5 mm do not show the lesion. Follow-up DWIs at b = 1000/3 mm, b = 2000/3 mm, and b = 3000/3 mm show a bright lesion (arrows) in the right hippocampal body, though the signal intensity-to-noise ratio becomes poor by increasing the b-value.

Patient summary and lesion detection on 8 different DWIs

Patient No.	Sex/Age	Time Lapse to Initial MRI	Lesion No.	Location	Initial DWI b-Value (sec/m²)/Section Thickness (mm)^*				Follow-up DWI b-Value (sec/m²)/Section Thickness (mm)^†
Patient No.	Sex/Age	Time Lapse to Initial MRI	Lesion No.	Location	1000/5	1000/3	2000/3	3000/3	1000/5	1000/3	2000/3	3000/3
1	F/59	3:00	3	R body	-	-	-	-	+	+	+	+
				L head	-	-	-	-	-	+	+	+
				R temporal	-	-	-	-	-	+	+	+
2	M/63	4:30	1	L body	-	-	+	+	+	+	+	+
3	F/50	4:30	1	R body	-	-	-	-	-	+	+	+
4	F/54	4:30	3	L head	-	+	+	+	+	+	+	+
				R body	-	-	-	-	+	+	+	+
				L body	-	-	-	-	+	+	+	+
5	F/65	5:30	1	L body	-	-	-	-	+	+	+	+
6	F/69	7:00	1	R body	-	-	-	-	+	+	+	+
7	F/69	9:00	4	R head	-	+	+	+	+	+	+	+
				R body	-	+	+	+	+	+	+	+
				L head	-	+	+	+	+	+	+	+
				R body	-	-	-	-	-	-	+	+
8	F/49	11:15	1	R head	-	+	+	+	+	+	+	+
9	M/60	14:30	2	R head	+	+	+	+	+	+	+	+
				L head	-	-	+	+	-	+	+	+
10	F/52	19:15	2	R body	-	-	+	+	+	+	+	+
				L body	-	-	-	-	-	+	+	+
11	F/64	19:15	1	L body	-	-	-	-	-	-	+	+
12	F/61	19:30	3	R head	+	+	+	+	+	+	+	+
				R body	+	+	+	+	+	+	+	+
				L head	-	-	+	+	+	+	+	+
13	F/57	22:15	1	R head	-	+	+	+	+	+	+	+

Note:—MRI, indicates MR imaging; R, right; L, left; temporal, temporal lobe; +, lesion detected; −, lesion not detected.
* Detection rates: 1000/5 = 13%, (3/24); 1000/3 = 38% (9/24); 2000/3 = 54% (13/24); 3000/3 = 54% (13/24).
† Detection rates: 1000/5 = 71% (17/24); 1000/3 = 92% (22/24); 2000/3 = 100% (24/24); 3000/3 = 100% (24/24).