Semiautomated MRI-Based Method for Orbital Volume and Contour Analysis.

OBJECTIVE: The architecture of the orbital cavity is intricate, and precise measurement of its growth is essential for managing ocular and orbital pathologies. Most methods for those measurements are by CT imaging, although MRI for soft tissue assessment is indicated in many cases, specifically pediatric patients. This study introduces a novel semiautomated MRI-based approach for depicting orbital shape and dimensions. DESIGN: A retrospective cohort study. PARTICIPANTS: Patients with at least 1 normal orbit who underwent both CT and MRI imaging at a single center from 2015 to 2023. METHODS: Orbital dimensions included volume, horizontal and vertical lengths, and depth. These were determined by manual segmentation followed by 3-dimensional image processing software. MAIN OUTCOME MEASURES: Differences in orbital measurements between MRI and CT scans. RESULTS: Thirty-one patients (mean age 47.7 ± 23.8 years, 21 [67.7%]) females, were included. The mean differences in delta values between orbital measurements on CT versus MRI were: volume 0.03 ± 2.01 ml, horizontal length 0.53 ± 2.12 mm, vertical length, 0.36 ± 2.53 mm, and depth 0.97 ± 3.90 mm. The CT and. MRI orbital measurements were strongly correlated: volume (r = 0.92, p < 0.001), horizontal length (r = 0.65, p < 0.001), vertical length (r = 0.57, p = 0.001), and depth (r = 0.46, p = 0.009). The mean values of all measurements were similar on the paired-samples t test: p = 0.9 for volume (30.86 ± 5.04 ml on CT and 30.88 ± 4.92 ml on MRI), p = 0.2 for horizontal length, p = 0.4 for vertical length, and p = 0.2 for depth. CONCLUSIONS: We present an innovative semiautomated method capable of calculating orbital volume and demonstrating orbital contour by MRI validated against the gold standard CT-based measurements. This method can serve as a valuable tool for evaluating diverse orbital processes.

Orbital Development in Children with Retinoblastoma: An Imaging-Based Study.

PURPOSE: To examine whether children treated for Retinoblastoma (Rb) have impaired orbital development. METHODS: A retrospective case series was performed among children with Rb treated at a single medical center from 2004 to 2020. Orbital volumes and measurements were assessed by 3-dimensional image processing software. The main outcome measures were differences in orbital growth between Rb and non-Rb eyes assessed at last follow-up. RESULTS: Among 44 patients included (mean age 16.09 ± 18.01 months), a positive correlation between age and orbital volume was observed only in the uninvolved, healthy eyes (p = .03). In unilateral cases, orbital growth in the horizontal, vertical, and depth planes was smaller on the affected side compared to the healthy eyes (p < .05). Orbits that underwent enucleation showed decreased growth over time compared to those treated conservatively (p = .017). CONCLUSIONS: Orbital growth rate is slower in the orbits of children treated for Rb compared to healthy orbits. Enucleation negatively affects orbital growth.

GRAding of functional and anatomical response to DExamethasone implant in patients with Diabetic Macular Edema: GRADE-DME Study.

To analyze functional and anatomical response patterns to dexamethasone (DEX) implant in diabetic macular edema (DME), to describe proportion of responders and non-responders, and to propose a new DME grading system. Retrospective, multicenter, observational cohort study. Naïve and non-naïve DME patients were treated with DEX, with visual acuity (VA) ≥ 0.2 logMAR and central subfield thickness (CST) of ≥ 300 µm. Functional and anatomical responses were graded after 2 and 4 months, and categorized as early and stable improvement, early and progressive improvement, pendular response, delayed improvement, and persistent non-response. 417 eyes were included (175 treatment naïve eyes). Compared to non-naïve eyes, naïve eyes showed a very good functional response (VA gain ≥ 10 letters) more frequently after 2 and 4 months (56% and 57% [naïve] vs. 33% and 28% [non-naïve], p < 0.001). A VA gain < 5 letters (non-response) after 2 and 4 months was seen in 18% and 16% of naïve eyes, and in 49% and 53% of non-naïve eyes (p < 0.001). A lack of anatomical response was rare in both groups, but more frequently in non-naïve eyes (12% vs. 4%, p = 0.003). Functionally and anatomically, naïve eyes showed most frequently an early and stable improvement (functionally: 77/175 44%; anatomically: 123/175 eyes, 70%). Most non-naïve eyes experienced no significant improvement functionally (97/242 eyes, 40%), despite a mostly early and stable improvement anatomical response pattern (102/242 eyes, 42%). Functional but not anatomical response patterns were influenced by baseline VA. Naïve and non-naïve eyes show different functional and anatomical response patterns to DEX implant. Functional non-responders are rare in naïve eyes, whereas anatomical non-response is unusual in both groups.