Chen Z, et al. – This pilot MRI structural imaging study intended to examine altered periaqueductal gray (PAG) volume in episodic migraine (EM) patients based on high–resolution brain structural image. In EM, PAG volume expansion possibly served as the direct impairment evidence on the brain, and could be considered as a diagnostic and evaluated imaging biomarker in migraine.

• The authors obtained the brain structural images from 18 normal controls (NC), 18 EM patients and 16 chronic migraine (CM) on 3.0 T MR system.
• They created PAG template based on the ICBM152 gray matter template using MRIcron, and the individual PAG was created by applying the deformation field to the PAG template after structural image segment.
• They applied one-way analysis of covariance, partial correlation analysis, and Receiver operating characteristics (ROC) curve.

• Comapred to NC (P = 0.017) (0.32 ± 0.02 ml), EM had a larger PAG volume (0.35 ± 0.02 ml).
• The PAG volume of CM (0.33 ± 0.02 ml) was negatively correlated with the VAS score (P = 0.03).
• ROC analysis showed that PAG volume had higher diagnostic efficacy (AUC, 0.731; Sensitivity, 0.556; Specificity, 0.889) for NC vs. EM than that of NC vs. CM (AUC, 0.634; Sensitivity, 0.438; Specificity, 0.833) and EM vs. CM (AUC, 0.618; Sensitivity, 0.813; Specificity, 0.556).