Citation: Tellouck L, Durieux M, Coupé P, et al. Optic radiations microstructural changes in glaucoma and association with severity: a study using 3Tesla-magnetic resonance diffusion tensor imaging. Invest Ophthalmol Vis Sci. 2016;57:6539-6547. DOI:10.1167/iovs.16-19838 PURPOSE. To compare microstructural changes along the optical radiations and brain structure volumes between glaucoma and control subjects using in vivo magnetic resonance imaging and to analyze their association with severity of the disease. METHODS.A total of 50 open-angle glaucoma subjects and 50 healthy age-and sex-matched controls underwent detailed ophthalmologic examinations (including visual field testing [VF], funduscopy, and spectral-domain optical coherence tomography) as well as diffusion tensor imaging (DTI) using 3.0-Tesla magnetic resonance imaging. Fractional anisotropy (FA), mean diffusivity, radial diffusivity (RD), and axial diffusivity (AD) were quantified semiautomatically along the optical radiations. DTI parameters and volumes of specific brain structures were compared between cases and controls using conditional logistic regression. Association between DTI metrics and the severity of the disease was studied using linear mixed regression analyses. RESULTS.In glaucoma subjects, optic radiations FA was significantly lower (0.57 vs. 0.59; P ¼ 0.02) and RD was significantly higher (52.78 10 -5 mm 2 /s vs. 49.74 10 -5 mm 2 /s; P ¼ 0.03) than in controls. Optic radiations FA was significantly correlated with homolateral functional and structural damage of glaucoma (mean deviation of VF [P ¼ 0.03], retinal nerve fiber layer thickness [P ¼ 0.03], vertical cup to disc ratio [P ¼ 0.0007]). Volume and DTI parameters of other brain structures (including hippocampus) were not significantly different between glaucoma patients and controls.CONCLUSIONS. We evidenced microstructural modifications along visual pathways of glaucoma patients and these alterations were correlated with disease severity. The association of glaucoma with other neurodegenerative alterations would need further exploration and a prospective follow-up of our cohort of subjects. (ClinicalTrials.gov number, NCT01621841).

BACKGROUND AND PURPOSE:In multiple sclerosis, gadolinium enhancement is used to classify lesions as active. Regarding the need for a standardized and accurate method for detection of multiple sclerosis activity, we compared 2D-spin-echo with 3D-gradient-echo T1WI for the detection of gadolinium-enhancing MS lesions.

We sought to evaluate the accuracy of myocardial perfusion imaging (MPI) using cadmium-zinc-telluride (CZT) SPECT cameras for the measurement of left ventricular (LV) global and regional function, and the performance of absolute wall motion (WM) and wall thickness (WT) measurements for the detection of myocardial scarring, using cardiac MR as a reference. Methods: Sixty patients with known or suspected coronary artery disease underwent MPI using a CZT SPECT camera, as well as cine and delayed enhanced cardiac MR. Gated MPI data were processed using quantitative gated SPECT software. LV global function was assessed by measuring LV end-diastolic volume (EDV), endsystolic volume (ESV), and ejection fraction (EF). Regional function was assessed by quantifying segmental WM and WT according to the 17-segment model. Myocardial scarring was quantified on each segment using delayed enhanced cardiac MR. Agreement between SPECT and cardiac MR was assessed using Pearson correlation and Bland-Altman analyses. The influence of measurement magnitude on the agreement was analyzed using Spearman correlation coefficients between the mean and SD of measurements. The performance of WM and WT for the detection of segments with more than 25% scar transmurality was assessed using receiver-operating-characteristic analysis. Results: Correlation between methods was excellent for EF (R 5 0.81, P , 0.0001) and ESV (R 5 0.88, P , 0.0001) and was good for EDV (R 5 0.71, P , 0.0001). Agreement was good for EF (bias, 22.7%; limits of agreement, 215.5 to 110.1) but was lower for EDV (bias, 229.7 mL; limits of agreement, 268.3 to 18.9) and ESV (bias, 29.9 mL; limits of agreement, 230.7 to 110.9). Correlation between methods was fair for WM (R 5 0.49, P , 0.0001) and WT (R 5 0.48, P , 0.0001). SPECT underestimated WT (bias, 241%; limits of agreement, 2108 to 126), with an error depending on thickening magnitude (r 5 0.70, P , 0.0001). The agreement in WM measurement was higher (bias, 21.4 mm; limits of agreement, 26.9 to 14) and independent of motion magnitude (r 5 0.006, P 5 0.86). WM and WT were equally able to identify scarred segments (area under the receiver-operating-characteristic curve, 0.74 6 0.03 and 0.74 6 0.03, respectively). Conclusion: MPI using CZT SPECT cameras and quantitative gated SPECT analysis accurately quantifies EF but still underestimates LV volumes. WM shows a higher agreement with cardiac MR than does WT, with errors in WT measurement increasing at greater thicknesses. Absolute quantification of segmental WM and WT can equally be used to identify myocardial scarring.

No abstract

3.