Hypoperfusion of Amygdala in Chronic Migraine: An Exploratory Quantitative Perfusion Imaging Using 3D Pseudo-Continuous Arterial Spin Labeling.

BACKGROUND: Although the amygdala has structural and functional abnormalities in Chronic Migraine (CM), less is known about the altered perfusion of the amygdala in CM.

OBJECTIVE: The current study aimed to assess amygdala perfusion in CM using a contrast agent-free and quantitative approach.

METHODS: 15 Normal Controls (NC) and 13 patients with CM during the migraine interval were assessed for brain structure and subjected to 3D Pseudo- Continuous Arterial Spin Labeling (3D-PCASL) MR imaging. The Cerebral Blood Flow (CBF) value of the amygdala was automatically extracted based on the individual amygdala mask for all participants. The independent sample t-test, Receiver Operating Characteristic (ROC) curve, and correlation analysis were used to evaluate the perfusion changes in CM.

RESULTS: Bilateral amygdala cerebral perfusion was lower in CM (left amygdala, 42.21±4.49 ml/100mg/min; right amygdala, 42.38±4.41 ml/100mg/min) than in NC (left amygdala, 48.31±6.92 ml/100mg/min; right amygdala, 47.88±6.53 ml/100mg/min) (left, p = 0.01; right, p = 0.02). There was no significant correlation between the perfusion of bilateral amygdalas and the clinical variables. Also, there was no significant difference in the volume of bilateral amygdalas between the two groups. The Area Under the Curve (AUC) of the CBF values of the left and right amygdala was 0.78 (95%CI: 0.58-0.91) and 0.75 (95%CI: 0.55-0.89), respectively. The cut-off value was 44.24 ml/100mg/min (left amygdala, with sensitivity 76.90% and specificity 78.70%) and 46.75 ml/100mg/min (right amygdala, with sensitivity 92.3% and specificity 58.80%), respectively.

CONCLUSION: CM presented bilateral hypoperfusion in the amygdala, offering potential diagnostic value in distinguishing CM from NC. The 3D-PCASL could be regarded as a simple and efficient neuroimaging tool to assess the perfusion status in CM patients.