# Evaluation of meningeal lymphatic vessels with delayed contrast enhanced vessel-wall MRI in cerebral infarction

## TL;DR

This study uses MRI to observe how contrast agents clear in patients with cerebral infarction and Moyamoya disease, suggesting delayed enhancement may reflect altered brain clearance.

## Contribution

The study introduces a method using delayed contrast-enhanced VW-MRI to evaluate meningeal lymphatic vessels in cerebral infarction and MMD.

## Key findings

- Large infarctions showed delayed meningeal enhancement, while small ones did not.
- Delayed enhancement was not observed in MMD outside postoperative regions.
- DANTE T1-SPACE imaging parameters were validated for detecting subtle contrast enhancement.

## Abstract

Observation of the clearance of gadolinium-based contrast agents (GBCA) in patients with cerebral infarction and Moyamoya disease (MMD) using vessel-wall MRI (VW-MRI).

This prospective study included 11 patients with recent cerebrovascular disorder and 6 patients with MMD who were scheduled for VW-MRI. All participants underwent whole brain delay alternating with nutation for tailored excitation-prepared T1-weighted variable flip angle turbo spin echo (DANTE T1-SPACE) imaging before, immediately after, and 1–6 h after gadolinium injection. Additionally, a phantom experiment was conducted to assess the signal intensity according to T1 values using DANTE T1-SPACE and 3D real inversion recovery sequences.

All five large infarction cases (≥ 5 cm) had delayed meningeal enhancement on the ipsilateral side, while none of the remaining six small infarction cases (< 5 cm) exhibited delayed meningeal enhancement on MRI. More than half of the entire cases had delayed white matter enhancement adjacent to the infarction. No MMD cases showed delayed enhancement outside postoperative regions. In the phantom experiment, DANTE T1-SPACE (TR = 700–1300 ms) demonstrated stable signal intensity across a T1 range of approximately 500–1000 ms. This T1 range corresponds to signal intensity ≈ 200–600 typically observed in regions showing delayed enhancement in clinical stroke and MMD cases.

Delayed meningeal enhancement observed in patients with large cerebral infarctions likely reflects alterations in brain clearance pathways. The absence of such enhancement in MMD supports that these enhancements are not attributable to collateral circulation. Phantom validation confirmed that the imaging parameters used in the DANTE T1-SPACE sequence were sufficient to detect subtle contrast enhancement in the clinically relevant T1 range.