Intrathecal gadolinium-enhanced magnetic resonance cisternography with three-dimensional fluid-attenuated inversion recovery and T1-weighted imaging: new perspectives on arachnoid cysts.

内容摘要

To assess the communication status of arachnoid cysts (ACs) and examine the findings of intrathecal gadolinium-enhanced magnetic resonance cisternography (IGMRC) using three-dimensional (3D) T1-weighted (T1W) and fluid-attenuated inversion recovery (FLAIR) sequences. A total of 44 cases of ACs that underwent IGMRC were included in the study. The degree of opacification was assessed on both early-phase (EP) and late-phase (LP) 3D T1W and 3D FLAIR images. Opacification levels on EP- and LP-FLAIR sequences were evaluated in cysts classified as complete, incomplete, or non-communicating (NC) based on 3D T1W imaging findings. The opacification rate was 54.5% on EP-T1, 79.5% on EP-FLAIR, 79.5% on LP-T1, and 95.4% on LP-FLAIR. Significantly higher-grade opacification was observed on EP-FLAIR than on EP-T1 and on LP-FLAIR than on LP-T1. Completely communicating cysts exhibited higher-grade opacification on EP-T1 than on EP-FLAIR, whereas incompletely communicating cysts showed higher-grade opacification on both EP- and LP-FLAIR than on T1 images. Opacification was detected on LP-FLAIR in 77.8% of cysts initially categorized as NC according to 3D T1W imaging. Combining both T1W and FLAIR sequences provides the most comprehensive evaluation and may reduce the need for LP imaging. Considering that most cysts that appear NC on T1W imaging demonstrate opacification on LP-FLAIR, it is suggested that the majority of ACs may be connected to the cerebrospinal fluid (CSF) spaces in some manner. However, due to factors such as cyst location and size and the dose of contrast agent used, they may not opacify sufficiently in cisternography studies. FLAIR sequences demonstrate higher sensitivity for detecting intrathecal contrast within ACs and may reveal communication with CSF spaces that cannot be identified using conventional T1W imaging alone.