# Transient Global Amnesia and High-Grade Styloidogenic Jugular Vein Stenosis

## TL;DR

This study suggests that high-grade jugular vein stenosis may be a new imaging risk factor for transient global amnesia.

## Contribution

The study identifies high-grade styloidogenic jugular vein stenosis as a potential novel imaging marker for transient global amnesia.

## Key findings

- Right-sided and combined bilateral jugular vein stenosis were significantly greater in TGA patients compared to controls.
- A 70% stenosis threshold in right or bilateral internal jugular veins may serve as a risk factor for TGA.
- MRI assessment of jugular vein stenosis could improve diagnostic accuracy for atypical TGA cases.

## Abstract

Could styloidogenic jugular vein compression (SJVC) severity represent a novel adjunctive imaging risk factor associated with a transient global amnesia (TGA) diagnosis?

In this case-control study of 84 patients, right-sided SJVC stenosis (70% vs 52%) and combined right and left stenosis (68% vs 55%) were significantly greater in patients with TGA vs healthy controls.

The findings of this study suggest that TGA is associated with high-grade SJVC in patients with small-caliber internal jugular veins, with a right-sided or bilateral stenosis of approximately 70% as a potential risk factor for TGA.

This case-control study assesses whether unilateral or bilateral styloidogenic jugular vein compression severity could serve as a novel adjunctive imaging factor associated with a transient global amnesia diagnosis.

Pathogenesis of focal hippocampal ischemia in transient global amnesia (TGA) remains unclear but may be of venous origin. Brain magnetic resonance imaging (MRI)–restricted diffusion has considerable limitations as the only current TGA imaging marker, highlighting a critical need for more reliable disease determinants.

To assess whether the severity of unilateral or bilateral styloidogenic jugular vein compression (SJVC), which can impair intracranial venous drainage, could serve as a novel adjunctive imaging risk factor associated with TGA diagnosis.

This retrospective case-control study of patients with TGA and hippocampal-restricted diffusion and without TGA but with hippocampal-restricted diffusion and healthy controls was conducted from May 2016 to June 2024 in a single large academic medical center.

A brain MRI including diffusion-weighted imaging and extended multiplanar volumetric postcontrast sequences revealing the internal jugular veins (IJVs) in the upper neck.

Calculations of cross-sectional areas and the percentage of SJVC stenosis in both IJVs were assessed. The primary outcome was the association of right, left, and combined bilateral SJVC stenosis with TGA status. Secondary measures included IJV baseline size and asymmetry.

There were 84 approximately age-matched and sex-matched patients and healthy controls (mean [SD] age, 66 [11.7] years) included in this study; 44 (52.4%) were female, and 40 (47.6%) were male. All participants had brain MRIs: 28 with clinical TGA and hippocampal-restricted diffusion (TGA+/MRI+), 28 without clinical TGA but with incidental hippocampal-restricted diffusion (TGA−/MRI+), and 28 controls without TGA or restricted diffusion (TGA−/MRI−). Right IJVs were larger in all groups, left IJVs were significantly smaller in TGA+/MRI+ than in controls (mean [SD] axial area, 45.0 [30.0] mm2 vs 60.7 [27.5] mm2; P = .04), and the combined IJV caliber was significantly smaller in TGA+/MRI+ than in controls (mean [SD] axial areas, 126.7 [37.1] mm2 vs 150.6 [28.8] mm2; P = .009). Left SJVC stenosis was not associated with patient cohort, but right mean (SD) SJVC stenosis was significantly greater in TGA+/MRI+ than in TGA−/MRI+ (70.4% [30.7%] vs 56.7% [24.1%]; P = .01) and in controls (70.4% [30.7%] vs 51.8% [20.1%]; P = .001). Combined mean (SD) stenosis was also greater in TGA+/MRI+ than in controls (67.5% [24.9%] vs 54.6% [16.1%]; P = .01). Logistic regression demonstrated that right SJVC stenosis (odds ratio, 1.36 [95% CI, 1.06-1.75]; P = .007) and combined stenosis (odds ratio, 1.38 [95% CI, 1.02-1.86]; P = .02) were associated with TGA when compared with controls.

In this case-control study of patients with TGA vs healthy participants, TGA was associated with high-grade SJVC in the presence of small-caliber IJVs, with an approximately 70% right-sided or bilateral IJV stenosis threshold emerging as a promising imaging covariate for supporting the clinical diagnosis of TGA. These results suggest that MRI assessment of SJVC severity may improve diagnostic accuracy in atypical TGA presentations.