Table 2.

Regions showing significant differences in ALFF between older patients with KOA and postoperative patients in comparison with healthy controls.

Cluster name	Brain region	Cluster size	MNI coordinates			Z valueb
			xa	ya	za
KOA patients (n = 23) vs. healthy controls (n = 23)
Cluster 1		4512
	Left precuneus gyrus		−11	−66	51	−5.80
	Right precuneus gyrus		12	−76	47	−5.82
	Left angular gyrus		−54	−60	30	−7.47
	Right angular gyrus		53	−54	38	−5.42
Cluster 2		1244
	Left medial superior frontal gyrus		−12	63	12	−5.56
	Right medial superior frontal gyrus		13	59	20	−5.06
Cluster 3		8682
	Left cerebelum_9		−18	−51	−51	8.21
	Right cerebelum_8		28	−53	−52	6.96
	Left amygdala		−26	0	−11	6.60
	Right amygdala		25	4	−16	7.29
Postoperative patients (n = 15) vs. healthy controls (n = 23)
Cluster 4		5241
	Left precuneus gyrus		−7	−71	41	−5.70
	Right precuneus gyrus		8	−63	46	−5.63
	Left angular gyrus		−54	−60	30	−7.53
	Right angular gyrus		54	−60	34	−5.29
Cluster 5		1310
	Left medial superior frontal gyrus		−9	63	12	−5.43
	Right medial superior frontal gyrus		13	62	4	−4.31
Cluster 6		8591
	Left cerebelum_9		−21	−42	−45	7.36
	Right cerebelum_8		24	−54	−42	6.82
	Left amygdala		−24	1	−13	6.38
	Right amygdala		25	1	−17	6.70

ALFF, amplitude of low frequency fluctuation; KOA, knee osteoarthritis. The results were considered significant at p < 0.025 (two tailed, voxel-wise p < 0.001, GRF corrected).

^aCoordinates indicate location of maximum Z-scores for clusters or location of local maxima.

^bZ value: Maximum Z value of cluster or Z statistic of local maxima.