Combination of optical coherence tomography (OCT) and OCT angiography increases diagnostic efficacy of Parkinson's disease

Abstract

Background: To assess the diagnostic efficacy of optical coherence tomography (OCT) and OCT angiography (OCTA) in Parkinson's disease (PD).

Methods: OCT was used to obtain macular parameters and peripapillary retinal nerve fiber layer (RNFL) thickness. The macular superficial retinal vessel and foveal avascular zone (FAZ) were quantified with OCTA. The area under the receiver operating characteristic curve (AUC) indicated the diagnostic efficacy of the parameters.

Results: Thirty-five eyes from 35 PD patients and 35 eyes from 35 age-matched healthy subjects who served as controls were evaluated. The mean RNFL thickness overall and the thicknesses of the other three quadrants were similar in PD patients compared with controls (P≥0.358). The RNFL thickness at the temporal quadrant, total macular volume (TMV), macular retinal thickness (MRT), and ganglion cell-inner plexiform layer complex (GCL-IPL) thickness were reduced in the eyes of PD patients (P≤0.046). There was no difference between the CMT of PD patients compared with control subjects (P=0.163). The vessel length density (VLD) in the central, inner and full regions; vessel perfusion density (VPD) in all regions; and the FAZ circularity index in PD patients were significantly lower than in controls (P≤0.049). The AUC of the VLD in PD in the central, inner and full regions were 0.712, 0.728, and 0.650, respectively; The VPD in the central, inner and full region were 0.711, 0.756, and 0.682, respectively. The mean RNFL thickness in the temporal quadrant, TMV and MRT revealed an AUC of 0.718, 0.693 and 0.699, respectively. The VPD in the outer region, FAZ circularity and GCL-IPL thickness did not have diagnostic ability in distinguishing PD from normal eyes (P≥0.05). The AUCs of a combination of the VLD in the inner region and TMV, the VLD in the inner region and MRT, the VPD in the inner region and TMV, and the VPD in the inner region and MRT, were 0.843, 0.849, 0.849, and 0.848, respectively (P≤0.001).

Conclusions: Decreased OCT and OCTA parameters were detected in the eyes of PD patients. Combined non-invasive measurements of OCT and OCTA had better diagnostic ability than either alone, and may provide an additional biomarker for PD progression.

Keywords: OCT angiography (OCTA); Parkinson’s disease (PD); diagnostic efficacy; optical coherence tomography (OCT).

Figure 1

Macular area measurement map. The central area is the center region. The inner, outer and full regions were calculated separately at various distances from the fovea: inner (1–3 mm diameter region), outer (3–6 mm diameter region) and full (6 mm diameter region).

Figure 2

ROC curve analysis of the OCT and OCTA parameters for discriminating PD patients from healthy controls. (A) ROC curve analysis of single OCTA parameters; (B) ROC curve analysis of single OCT parameters; (C) ROC curve of the combined assessment of VLD inner and TMV was 0.843 (95% CI: 0.750–0.936); (D) ROC curve of the combined assessment of VLD inner and MRT was 0.849 (95% CI: 0.757–0.941); (E) ROC curve of the combined assessment of VPD inner and TMV was 0.849 (95% CI: 0.759–0.939); (F) ROC curve of the combined assessment of VPD inner and MRT was 0.848 (95% CI: 0.757–0.940). OCT, optical coherence tomography; OCTA, OCT angiography; PD, Parkinson’s disease; AUC, area under the ROC curve; ROC, receiver-operating characteristic; VLD, vessel length density; VPD, vessel perfusion density; RNFL, retinal nerve fiber layer; GCL-IPL, ganglion cell-inner plexiform layer complex; TMV, total macular volume; MRT, macular retinal thickness.