# Differentiating mega cisterna magna from cisterna magna arachnoid cysts: The diagnostic utility of quantitative diffusion‐weighted imaging parameters

## TL;DR

This study shows that diffusion imaging can help distinguish between two similar brain conditions using specific imaging parameters.

## Contribution

The study demonstrates the diagnostic utility of ADC and eADC in differentiating mega cisterna magna from arachnoid cysts.

## Key findings

- MCM had significantly lower eADC values compared to CMAC and TAC.
- ADC values of MCM were significantly different from both CMAC and TAC.
- eADC did not significantly differentiate CMAC from TAC.

## Abstract

To explore the utility of diffusion‐weighted imaging (DWI)‐derived apparent diffusion coefficient (ADC) and exponential apparent diffusion coefficient (eADC) parameters in differentiating mega cisterna magna (MCM) from cisterna magna arachnoid cysts (CMAC).

Retrospective analysis of MRI data from 40 MCM patients, 46 CMAC patients (confirmed via clinical follow‐up and imaging criteria), and 36 temporal arachnoid cysts (TAC) as controls was performed. Independent sample t‐tests were used to compare ADC and eADC values among the three groups.

The eADC values of MCM, CMAC, and TAC were (3.75 ± 0.27) × 10−2, (4.53 ± 0.54)×10−2, and (4.35 ± 0.30) ×10−2 mm2/s, respectively. There was no significant difference in the eADC value between CMAC and TAC (p = 0.191). However, the eADC value of MCM was significantly different from the two groups (p = 0.000). The ADC values of MCM, CMAC, and TAC were (3.30 ± 0.08) × 10−3, (3.11 ± 0.12) ×10−3, and (2.97 ± 0.71) × 10−3 mm2/s, respectively. Significant differences in ADC were observed between MCM and both CMAC and TAC (p = 0.000/0.003).

DWI‐derived ADC and eADC parameters can effectively differentiate mega cisterna magna from cisterna magna arachnoid cysts.