ABSTRACT
ObjectiveTo compare the brain imaging characteristics in patients with knee osteoarthritis (KOA) and low back pain (LBP) based on amplitude of low frequency fluctuation (ALFF) of functional magnetic resonance imaging. MethodsFrom August, 2015 to September, 2021, 16 KOA patients and 16 healthy subjects (controls 1) with similar age and gender were recruited from the communities of Fuzhou, Fujian. Other 27 patients with LBP and 32 healthy subjects (controls 2) with similar age and gender were obtained from the Openpain database. The ALFF were analyzed. KOA patients were assessed the pain with Brief Pain Inventory (BPI), and LBP patients were assessed with Visual Analogue Scale (VAS). The correlation between ALFF and pain scores was analyzed. ResultsCompared with their own controls, the ALFF decreased in the left anterior insula for both KOA and LBP patients. The ALFF decreased in the hippocampus and posterior cingulate cortex in KOA patients, while increased in LBP patients. ALFF in the left precuneus, left middle cingulate cortex and right periaqueductal gray matter decreased in KOA patients, and ALFF increased in the right precentral/postcentral gyrus. ALFF of bilateral anterior cingulate cortex, bilateral orbital anterior frontal cortex, left dorsolateral prefrontal cortex and right medial prefrontal cortex decreased in LBP patients, and ALFF increased in the right parahippocampal gyrus and right amygdala. ALFF of the left middle cingulate cortex negatively correlated with BPI score in KOA patients (r = -0.73, P = 0.003), and ALFF of the right hippocampus/amygdala positively correlated with VAS score in LBP patients (r = 0.73, P = 0.003). ConclusionThere are common and specific brain imaging features in different types of chronic pain. The alteration in the left anterior insula, hippocampus and posterior cingulate gyrus may be the common mechanism for KOA and LBP.