The detection of white matter alterations in obsessive–compulsive disorder revealed by TRActs Constrained by UnderLying Anatomy (TRACULA)

Figures & data

Figure 1 An example of reconstructed 18 white matter pathways: the corticospinal tract (violet), inferior longitudinal fasciculus (orange), uncinate fasciculus (blue), anterior thalamic radiation (yellow), cingulum cingulate gyrus (supracallosal) bundle (green), cingulum angular (infracallosal) bundle (CAB) (light green), superior longitudinal fasciculus parietal bundle (gray), superior longitudinal fasciculus temporal bundle (cyan), corpus callosum forceps major (FMaj) (red, posterior), and corpus callosum forceps minor (red, anterior).

Notes: Figures show an axial slice (A) and a sagittal slice (B).

Table 1 Demographic and clinical characteristics

Variables	OCD, n=25	HC, n=27	p-value
Age (years)	35.0 (±8.9)	32.4 (±6.7)	0.235
Gender (male/female)	7/18	13/14	0.163
Handedness (right/left)	23/2	26/1	0.603
Years of education	14.3 (±2.2)	15.4 (±2.0)	0.062
Age of onset (years)	25.9 (±8.6)	N/A	N/A
Duration of illness (years)	8.6 (±5.9)	N/A	N/A
Y-BOCS–total	22.2 (±6.7)	N/A	N/A
Y-BOCS–obsessions	11.0 (±3.1)	N/A	N/A
Y-BOCS–compulsions	11.1 (±3.8)	N/A	N/A
HAM-D 17	3.8 (±3.4)	N/A	N/A
HAM-A	5 (±4.5)	N/A	N/A

Note: Values represent the mean (±SD).

Abbreviations: HAM-A, Hamilton Anxiety Rating Scale; HAM-D, Hamilton Depression Rating Scale; HC, healthy control; N/A, not applicable; OCD, obsessive–compulsive disorder; Y-BOCS, Yale-Brown Obsessive Compulsive Scale.

Table 2 RD values of white matter tracts which showed significance in logistic regression analysis

White matter tract	RD (×10^−3 mm^2/s)		B	p-value
	OCD	HC
Forceps major	0.5756 (0.5437–0.6218)	0.5382 (0.4979–0.5910)	14,083	0.020
rh. cingulum angular (infracallosal) bundle	0.7557 (0.7360–0.7761)	0.7838 (0.7657–0.8031)	−36,150	0.004

Notes: Values represent the median (interquartile range).

Abbreviations: HC, healthy control; OCD, obsessive–compulsive disorder; RD, radial diffusivity; rh., right.

Figure 2 Reconstruction of the forceps major (FMaj, red) and the right cingulum-angular (infracallosal) bundle (CAB, cyan) in a representative OCD patient.

Notes: Figures show an axial (A) and a sagittal slice (C). Box plots show RD values of the FMaj (B) and the right CAB (D).
Abbreviations: HC, healthy control; OCD, obsessive–compulsive disorder; RD, radial diffusivity.

Table 3 Regression coefficient and p-values of two white matter tracts showing significance in Table 2, including (A) age and (B) age, gender, and handedness

Parameter in the tract	B	p-value
(A)
RD in forceps major (×10^−3 mm^2/s)	13,799	0.023
RD in rh. cingulum angular (infracallosal) bundle (×10^−3 mm^2/s)	−36,020	0.005
(B)
MD in forceps major (×10^−3 mm^2/s)	17,844	0.040
RD in rh. cingulum angular (infracallosal) bundle (×10^−3 mm^2/s)	−43,631	0.006

Abbreviations: MD, mean diffusivity; rh., right; RD, radial diffusivity.