# A case of atypical meningioma presenting spontaneous infarction: the findings of magnetic resonance imaging, including amide proton transfer-chemical exchange saturation transfer imaging

## TL;DR

This paper presents a case of an atypical meningioma with spontaneous infarction, using MRI and APT-CEST imaging to assess tumor viability and changes.

## Contribution

The study demonstrates the utility of APT-CEST imaging in evaluating tumor viability during infarction or ischemia.

## Key findings

- MRI showed spontaneous infarction with no enhancement and severe diffusion restriction.
- APT-CEST imaging revealed decreased signal during infarction, possibly due to acidosis and loss of viable tumor.
- Recurrent tumor showed increased APT-CEST signal and moderate diffusion restriction.

## Abstract

We report the MRI findings of a patient with an atypical meningioma who presented with spontaneous infarction. A 67-year-old man with histories of recurrent meningioma complained of left ocular protrusion and a subsequent biopsy revealed atypical meningioma. Contrast-enhanced CT showed a uniformly enhancing tumour in the left ethmoid sinus, but MRI 2 days later showed no enhancement on Gd-T1WI and severe diffusion restriction on DWI, indicating spontaneous infarction. APT-CEST imaging showed slight hypointensity in comparison to the normal brain with a mean MTR asymmetry value of 0.48%. Tumour regrowth was confirmed on MRI after 2 months. The recurrent tumour showed moderate diffusion restriction on DWI and hyperintensity with a mean MTR asymmetry value of 2.59% on APT-CEST imaging. The decreased signal on APT-CEST at the time of spontaneous infarction may have been attributed to intratumoral acidosis and loss of viable tumour. APT-CEST imaging is useful for evaluating the intratumoral condition and tumour viability of the infarcted or ischemic tumour.