Ocular Volumetry Using Fast High-Resolution MRI during Visual Fixation

Sequential contiguous half-Fourier single-shot RARE images of the right eye of a female volunteer. Two radiologists manually measured the areas of the anterior chamber and the whole eyeball (enclosed with a gray and a white freehand line in the centered figure, respectively) on each image and calculated their volumes by multiplying the sum of the areas by each section thickness.

Imaging and intraobserver reproducibility on ocular MR volumetry. The right eyes of 15 volunteers were scanned twice in 1 week. Bland-Altman analysis shows the comparison of the volumes of the anterior chamber or whole eyeball between the first and second scans. Data are shown for each of the 2 observers. The central line (mean) indicates the bias, and the outer broken lines (mean ± 2 SDs) indicate the limits of agreement.

Boxplots showing volumetric data measured by each of the 2 observers in the first and second scans (A, anterior chamber. B, whole eyeball). Although no interobserver difference for the measured anterior chamber volumes was evident, volumes of the whole eyeball measured by observer B were higher than those measured by observer A.

Half-Fourier single-shot RARE images in the follow-up of a 7-year-old girl with Sturge-Weber syndrome. In the first (A) and the second (B) scans, contiguous half-Fourier single-shot RARE images show the convex-shaped relatively low-signal-intensity subretinal fluid and relatively high-signal-intensity choroidal hemangioma in the left eye. The measured volumes of the whole eyeball, the tumor, and the subretinal fluid in the first scan were 6.55 × 10³ mm³, 1.32 × 10³ mm³, and 0.61 × 10³ mm³, respectively. The corresponding volumes in the second scan were 6.50 × 10³ mm³, 1.33 × 10³ mm³, and 0.34 × 10³ mm³, respectively. Although no notable change in the volumes of the whole eyeball and the tumor were found, the volume of subretinal fluid decreased by 44% after 11 weeks.