Fig 1.
Grading of compression/stenosis using Contrast-enhanced MR (magnetic resonance) imaging.
(A): Grading of IJV (internal jugular vein) compression/stenosis by Contrast T1 (contrast-enhanced axial T1-weighted MR imaging). Grade 0: normal round or ovoid (a), Grade 1: mild flattening (b, c); Grade 2: moderate flattening (d); Grade 3: severe flattening (e), pinpoint (f) or not visualized. (B): Grading of left BCV (brachiocephalic vein) compression/stenosis by TRICKS (time-resolved imaging of contrast kinetics). Grade 0: normal (a, arrowhead), Grade 1: BCV with mild filling defect by the aortic compression (b, arrowhead); Grade 2: left BCV interrupted at the aortic arch (c, arrowhead) with filling defect, but without collateral; Grade 3: left BCV compression/occlusion (d-e, arrowhead) with different types of venous collaterals filling and reflux: Venous flow drains across the midline into the right IJV through the anterior cervical veins from left subclavian vein (d, vertical arrow); Reflux of IJV (d, horizontal arrow), the contrast medium injected from left subclavian vein appeared retrograde into left IJV; Collaterals of vertebral venous system, presence of collaterals of vertebral venous system, from the left subclavian vein draining directly through intrarachidian anastomoses to contralateral side at different levels (e, arrows). (C): Grading of TS (transverse sinus) asymmetry by MRV (magnetic resonance venography) (C a–C d). Grade 0: symmetrical TS (a); Grade 1: TS asymmetry≤50%(b); Grade 2: TS asymmetry >50% (c); and Grade 3 aplasia or signal absent (arrowhead pointing locations for comparison) (d). Grading of TS asymmetry by Contrast T1(C e–C h). Grade 0: symmetrical TS (e), Grade 1: TS asymmetry≤50% (f); Grade 2: TS asymmetry>50%(g); and Grade 3:aplasia or signal absent(arrowhead pointing locations for comparison) (h).
Table 1.
Demographic Data and Clinical Features of TGA Patients and Controls.
Table 2.
Comparison of the Degree of Venous Compression in the Internal Jugular Vein (IJV) and Brachiocephalic Vein (BCV) in Magnetic Resonance (MR) Imaging in TGA Patients and Controls.
Fig 2.
Differences between TGA (transient global amnesia) patients and controls in the frequencies of any significant venous compression of the venous outflow route on an individual basis.
** P<0.01, *** P<0.001. BCV left brachiocephalic vein compression, IJV internal jugular vein, Upper IJV Upper IJV compression at either side, Middle IJV Middle IJV compression at either side, B/U/Mat least one site of venous compression/stenosis at left BCV or either side of Upper IJV or Middle IJV.
Table 3.
The Diameters of Transverse Sinus (TS) and TS h\Hypoplasia by Magnetic Resonance Venography (MRV) and Contrast-enhanced axial T1-weighted magnetic resonance imaging (Contrast T1) in TGA Patients and Controls.
Fig 3.
Display of Doppler spectra in IJV (internal jugular vein) during VM (Valsalva maneuver) in sitting.
(A) Patient 1. Anterograde flow in right IJV during VM in sitting (upper panel, A) suggests the pressure can be released by the reopening IJV in a 42-year-old healthy woman with IJV patency. (B)Patient 2. No flow in right IJV during VM in sitting (lower panel, B)with transient venous reflux (arrow, B) indicates the intracranial venous pressure can’t be effectively relieved through the reopening of the IJV in a 53-year-old TGA patient with significant IJV stenosis/obstruction. Arrows indicate beginning of VM, arrowheads indicate end of VM.