<p>Altered amplitude of low-frequency fluctuation and regional cerebral blood flow in females with primary dysmenorrhea: a resting-state fMRI and arterial spin labeling study</p>

Abstract

Purpose: The current study aimed to explore the central mechanism of primary dysmenorrhea (PD) by investigating the alterations in resting state amplitude of low-frequency fluctuation (ALFF) and regional cerebral blood flow (CBF) between PD patients and healthy controls (HCs). Patients and methods: A total of 34 female subjects including 20 PD patients and 14 HCs underwent resting-state functional magnetic resonance imaging (rs-fMRI) and arterial spin labeling technique (ASL) MRI during menstrual phase. Subsequently, the differences in ALFF and CBF were compared in the two groups. The visual analog scores for pain (VAS-P) and for anxiety (VAS-A) were applied to assess cramping pain and related symptoms in PD patients. Finally, Pearson’s correlation analysis was performed to analyze relationships between the neuroimaging findings and clinical characteristics. Results: Compared to HCs, PD patients had decreased ALFF in the right cerebellum posterior lobe, right middle temporal gyrus, right parahippocampal gyrus, right hippocampus, right brainstem and left parietal lobe. In addition, elevated CBF values were observed in the right inferior frontal gyrus, right precentral gyrus, and right superior temporal gyrus. There was no significant correlation between ALFF, CBF values and clinical characteristics including onset age of dysmenorrhea, VAS-A, and VAS-P in PD patients. Conclusion: The preliminary alterations of ALFF and CBF values in PD patients were observed in different pain-related brain regions, which were involved in multiple dimensions of pain and pain modulation. The combination of rs-fMRI and ASL MRI might provide complementary information for a better understanding of the central mechanism in PD.

Altered Posterior Cerebellar Lobule Connectivity With Perigenual Anterior Cingulate Cortex in Women With Primary Dysmenorrhea

“…Previously, individuals with chronic low back-related leg pain(22) and low back pain(23) showed changed local connectivity and GM volume in the posterior cerebellum. Furthermore, the altered spontaneous activity(31) and glycometabolism(61) in the right posterior cerebellum lobe were detected in the PDM patients that further supported the results of abnormal posterior cerebellar connectivity in our study. Taken together, abnormal connectivity between the pACC and posterior cerebellum may reveal dysfunction in the ACC-cerebellar cognitive and emotion processing circuit in PDM.…”

“…A recent study of the rat model of recurrent headache (30) further demonstrated increased connectivity between the cerebellum and ACC, suggesting the participation of the cerebellum-ACC connectivity in the painrelated process. In PDM women, decreasing spontaneous activity in the right cerebellum posterior lobe (31) and increasing GM volume in the cerebellar tonsil (right VIIIa) (8) have been found. However, whether the cerebellum-ACC connection is aberrant and different cerebellum-ACC circuits correspond to different pain-related processes in PDM remain unknown.…”

Immediate Analgesic Effect of Acupuncture in Patients With Primary Dysmenorrhea: A fMRI Study

“…The precentral gyrus contributes to the provision of pain relief ( Lefaucheur et al, 2001 ). An arterial spin labeling study reported aberrant precentral gyrus activity in patients with PDM ( Zhang et al, 2019 ). Thus, a reduction in the rACC–left precentral gyrus resting-state FC may be the mechanism by which acupuncture affects pain modulation.…”

Altered intrinsic brain activity and regional cerebral blood flow in patients with chronic neck and shoulder pain

“…A study on classical trigeminal neuralgia by Chen et al [41] showed that the ALFF value of the right precentral gyrus was significantly higher in CTN patients when compared to HCs. Zhang et al [21] found that elevated CBF value was observed in the right precentral gyrus of females with primary dysmenor rhea.…”

“…Hence, ALFF does not completely explain the pathophysiological mechanism of pain. Recent studies have explored the relationship between CBF and rs-fMRI metrics [20,21]. Arterial spinlabelled (ASL) perfusion MRI permits noninvasive quantification of CBF, which can be grouped into three types: continuous labelling, pulsed labelling, and velocity selective labelling [22].…”