The ALFF Alterations of Spontaneous Pelvic Pain in the Patients of Chronic Prostatitis/Chronic Pelvic Pain Syndrome Evaluated by fMRI

Abstract

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a challenging entity with complicated symptoms for treatment in the male crowd. Accumulating evidence revealed the dysfunction in the central system should be a critical factor for the pathogenesis and development in the CP/CPPS. Therefore, we recruited 20 patients of CP/CPPS and 20 healthy male volunteers, aged 20 to 50 years. Through resting-state functional magnetic resonance imaging (fMRI), we analyzed the mean amplitude of low-frequency fluctuations (mALFF) and the mean fractional amplitude of low-frequency fluctuations (mfALFF) to reflect the spontaneous abnormal activated regions in the brains of CP/CPPS patients. Compared to the healthy controls, the group with CP/CPPS had significantly increased mALFF values in the thalamus and augmented fALFF values in the inferior parietal lobule and cingulate gyrus. Significant positive correlations were observed in the extracted mALFF values in the midbrain periaqueductal gray matter (PAG) and the pain intensity (r = 0.2712, p = 0.0019), mALFF values in the thalamus and the scores of Hospital Anxiety and Depression Scale (HADS) anxiety subscale (r = 0.08477, p = 0.0461), and mfALFF values in the superior frontal gyrus (SFG) and the scores of the HADS anxiety subscale (r = 0.07102, p = 0.0282). Therefore, we delineated the clinical alterations in patients of CP/CPPS that might be attributed to the functional abnormality of the thalamus, inferior parietal lobule, and cingulate gyrus. Among these regions, the PAG, thalamus, and SFG may further play an important role in the pathogenesis, with their regulating effect on pain or emotion.

Keywords: amplitude of low-frequency fluctuation; chronic prostatitis/chronic pelvic pain syndrome; fractional amplitude of low-frequency fluctuation; functional magnetic resonance imaging.

Figure 1

Significant alterations of mALFF between the PT and HC groups (p < 0.05, FDR Correction, p < 0.05) in the transverse position. The abnormal regions of increased mALFF values were marked in red colors. The darkness of red color implied the intensity of mALFF. mALFF: mean amplitude of low-frequency fluctuation, FDR: False Discovery Rates, PT: patient group, HC: healthy control.

Figure 2

Significant alterations in mfALFF between the PT and HC groups (p < 0.05, FDR Correction, p < 0.05) in the transverse position. Regions of red colors represented these areas had increased high values of mfALFF. Likewise, the darker the red color, the higher intensities of mfALFF. mfALFF: mean fractional amplitude of low-frequency fluctuation, FDR: False Discovery Rates, PT: patient group, HC: healthy control.

Figure 3

The Outcomes of Correlation Analysis among ROIs and Clinical Scale Scores. (a) The correlation between the scores of NRS and mALFF values in PAG (r = 0.2712, p = 0.0019, R² = 0.4620). (b) The correlation between the scores of HADS anxiety subscale and mALFF values in thalamus (r = 0.08477, p = 0.0461, R² = 0.2261). (c) The correlation between the scores of HADS anxiety subscale and mfALFF values in superior frontal gyrus (r = 0.07102, p = 0.0282, R² = 0.2667). There was no correlation between the relative values of mALFF and mALFF in the other ROIs and the scores of clinical scales. ROIs: regions of interest, NRS: Numeric Rating Scale, mALFF: mean amplitude of low-frequency fluctuation, PAG: periaqueductal gray matter, HADS: Hospital Anxiety and Depression Scale, mfALFF: mean fractional amplitude of low-frequency fluctuation.