# Contrast Enhancement of the Olfactory Recess Using Heavily T2-Weighted 3D Fluid-Attenuated Inversion Recovery Imaging (FLAIR)

## TL;DR

This study shows that the olfactory recess can be enhanced using a specific MRI technique, which could help in understanding neurological disorders.

## Contribution

The study demonstrates novel contrast enhancement patterns in the olfactory recess using heavily T2-weighted 3D FLAIR imaging.

## Key findings

- Contrast enhancement of the olfactory recess was observed in most cases on postcontrast and delayed postcontrast images.
- The relative enhancement was highest in 4-hour delayed postcontrast images.
- The enhancement pattern resembled that of cerebrospinal fluid spaces around other cranial nerves.

## Abstract

Purpose

This study aimed to assess the contrast enhancement of the olfactory recess using heavily T2-weighted 3D fluid-attenuated inversion recovery (FLAIR) imaging after intravenous gadolinium administration.

Methods

This retrospective study included 35 patients. The overall contrast enhancement of the bilateral olfactory recess between the precontrast, postcontrast, and 4-h delayed postcontrast T2-weighted 3D FLAIR images were subjectively evaluated. In addition, serial changes in signal intensity in the olfactory recess and other structures (other cerebrospinal fluid spaces and the pons) were objectively assessed.

Results

Subjective analysis showed that contrast enhancement of the olfactory recess was observed in 61 (right: 28, left: 33) and 67 (right: 32, left: 35) of 70 ears from 35 patients on postcontrast and 4-h delayed postcontrast T2-weighted 3D FLAIR images, respectively. In the objective analysis, the relative enhancement of the olfactory recess was the highest for 4-h delayed postcontrast images, followed by postcontrast images. This enhancement pattern was similar to that of the cerebrospinal fluid spaces surrounding the other cranial nerves.

Conclusion

The olfactory recess was enhanced using T2-weighted 3D FLAIR imaging. These findings may provide novel insights into cerebrospinal fluid and solute dynamics and may contribute to optimizing imaging protocols for evaluating related neurological disorders.