Eckel, Laurence J.

Purpose: Obesity is a major public health concern, and fat comprises a substantial portion of the orbital volume. We aimed to evaluate the relationship between body mass index (BMI) and orbital fat volume, and to assess whether BMI is associated with radiographic proptosis. Methods: We conducted a cross-sectional study of 99 orbits from patients who underwent orbital CT imaging between January 1 and December 31, 2018. Patients with systemic diseases affecting the orbits were excluded. When applicable, only the healthy orbit was analyzed. Subjects were evenly stratified into normal-weight, overweight, and obese groups by BMI. Using Visage Imaging Software, orbital structure volumes were measured. Orbital fat volume was calculated by subtracting extraocular muscle, globe, and optic nerve volumes from the total orbital volume. Multivariable linear regression, adjusted for age, gender, and race, assessed associations between BMI and orbital measurements. Results: Among individuals with BMI 17 to 25, total orbital volume increased by 1.20 cm 3 and orbital fat volume by 1.05 cm 3 per unit BMI. For BMI >25, both increased at a flatter slope. Obese patients had nearly double the orbital fat volume of normal-weight patients (10.7 vs. 5.4 cm 3 , p < 0.001). Radiographic proptosis trended higher in obese patients by 1.7 mm ( p = 0.114). Males had larger orbital structures and greater mean proptosis than females. Conclusions: Total orbital and fat volumes increased with BMI, particularly in the normal-to-overweight range. These findings support the need to update normative proptosis data and suggest weight loss may aid in managing mild symptomatic proptosis.

Dilated perivascular spaces (PVSs) are common and easily recognized on imaging. However, rarer giant tumefactive PVSs (GTPVSs) can have unusual multilocular cystic configurations, and are often confused for other pathologic entities, including neoplasms, cystic infarctions, and neuroepithelial cysts. Because GTPVSs are scarcely encountered and even more infrequently operated upon, many radiologists are unaware of the imaging and pathologic features of these lesions. Here, a case of a resected GTPVS is presented, highlighting both its radiologic and histologic characteristics, and discussing how such lesions can be differentiated from their closest mimickers on imaging.

Purpose Imaging changes in the pituitary volume during pregnancy remains scantly researched. This study set out to assess the differences in total, anterior, and posterior pituitary volume in pregnant women compared to nulliparous and post-partum women. Materials and Methods A retrospective review was completed of women that had undergone MRI imaging of the brain. Patients were divided into three cohorts: pregnant, nulliparous, and post-partum (defined as being within 12 months of delivery). Anterior and posterior pituitary volumes were manually measured. Results 171 patients were included, of which 68 were pregnant, 52 were post-partum, and 51 were nulliparous. The average anterior (621.0 ± 171.6 mm 3 ) and total (705.4 ± 172.2 mm 3 ) pituitary volumes were significantly larger in pregnant patients than nulliparous women (522.6 ± 159.8 mm 3 and 624.5 ± 163.7 mm 3 , respectively) ( p = .002 and p = .01, respectively). The posterior pituitary volume was significantly smaller in pregnant women (84.4 ± 32.9 mm 3 ) compared to both post-partum (101.2 ± 42.0 mm 3 ) and nulliparous (102.0 ± 46.1 mm 3 ) women ( p = .02 for both). Conclusions The anterior and total pituitary volumes are significantly larger during pregnancy persisting into the post-partum period. The posterior pituitary volume, conversely, decreases during pregnancy, and returns to its normal size in the post-partum period.

Purpose: The purpose of this study was to characterize intradiploic dermoid and epidermoid orbital cysts to determine any differences in clinical, radiographic, or surgical features. Methods: A retrospective review was performed of patients presenting with intradiplopic dermoid or epidermoid cysts. Additionally, a complete review of the literature was performed to identify cases of intradiplopic orbital dermoid and epidermoid cysts. Data collected included age, sex, presenting symptoms, location of intradiplopic cyst, ophthalmic findings, treatment, and follow-up. Clinical features of dermoid versus epidermoid cyst were compared. Additionally, machine-learning algorithms were developed to predict histopathology based on clinical features. Results: There were 55 cases of orbital intradiploic cysts, 49 from literature review and six from our cohort. Approximately 31% had dermoid and 69% had epidermoid histopathology. Average age of patients with dermoid cysts was significantly lesser than that of patients with epidermoid cysts (23 vs. 35 years, respectively; P = 0.048). There was no difference between sex predilection, presenting symptoms, radiographic findings, or surgical treatment of dermoids and epidermoids. The majority of patients (64%) underwent craniotomy for surgical removal. Machine-learning algorithms KStar and Neural Network were able to distinguish dermoid from epidermoid with accuracies of 76.3% and 69%, respectively. Conclusion: Orbital intradiploic cysts are more commonly epidermoid in origin. Dermoid cysts presented in younger patients; however, there were no other significant differences in features including ophthalmic or radiographic findings. Despite similar features, machine learning was able to identify dermoid versus epidermoid with good accuracy. Future studies may examine the role of machine learning for clinical guidance as well as new surgical options for intervention.

Purpose: To identify risk factors for the development of new-onset, postoperative diplopia following orbital decompression surgery based on patient demographics, clinical exam characteristics, radiographic parameters, and surgical techniques. Methods: We conducted a multi-center retrospective chart review of patients who underwent orbital decompression for thyroid eye disease (TED). Patient demographics, including age, gender, smoking history, preoperative exophthalmometry, clinical activity score (CAS), use of peribulbar and/or systemic steroids, and type of orbital decompression were reviewed. Postoperative diplopia was determined at a minimum of 3 months postoperatively and before any further surgeries. Cross-sectional area ratios of each extraocular muscle to orbit and total fat to orbit were calculated from coronal imaging in a standard fashion. All measurements were carried out using PACS imaging software. Multivariable logistic regression modeling was performed using Stata 14.2 (StataCorp, College Station, TX). Results: A total of 331 patients without preoperative diplopia were identified. At 3 months postoperatively, 249 patients had no diplopia whereas 82 patients developed diplopia. The average postoperative follow-up was 22 months (range 3–156) months. Significant preoperative clinical risk factors for postoperative diplopia included older age at surgery, proptosis, use of peribulbar or systemic steroids, elevated clinical activity score, and presence of preoperative compressive optic neuropathy. Imaging findings of enlarged cross-sectional areas of each rectus muscle to the overall orbital area also conferred a significant risk of postoperative diplopia. Regarding surgical factors, postoperative diplopia was more common among those undergoing medial wall decompression, bilateral orbital surgery, and balanced decompression, whereas endoscopic medial wall decompression was found to be relatively protective. Conclusions: This study identifies risk factors associated with the development of diplopia following orbital decompression using multivariable data. This study demonstrates that several characteristics including age, clinical activity score, the cross-sectional muscle to orbit ratios, in addition to the type of orbital decompression surgery, are predictive factors for the development of new-onset postoperative diplopia.

Myxopapillary ependymomas (MPEs) have an indolent clinical course, corresponding to World Health Organization Grade I. A total of 13 pediatric MPEs have been reported in the literature with “anaplastic features,” including elevated proliferative activity (≥5 mitoses/10 high-power fields), necrosis, and microvascular proliferation. No consensus exists regarding the prognostic significance of such features. A retrospective clinicopathologic review of pediatric MPEs diagnosed between 1996 and 2018 at Mayo Clinic was performed. Totally, 8 pediatric MPEs (6 male; age: 7.52 to 16.88 y) were identified. Totally, 3 had disseminated disease at presentation. All patients underwent surgical resection (7 gross total; 1 subtotal). Totally, 5 cases harbored ≥5 mitoses/10 high-power fields (range: 5 to 9), 3 of which showed necrosis (2 with disseminated disease). Postsurgery, 2 patients received radiation; one with disseminated disease and another with increased mitotic activity/necrosis; neither has recurred (follow-up: 1.18 and 3.19 y). In all, 2 patients with disseminated disease, elevated mitotic activity, and necrosis had new metastatic disease/progression of nonresected metastatic foci (2.6 and 26.8 mo), received radiation therapy, and remain progression free (3.01 and 9.34 y). All patients are alive (median follow-up 1.31 y, range: 0.66 to 11.75). Among pediatric MPEs, the concurrent presence of elevated mitotic activity and necrosis may be associated with an aggressive clinical course, warranting closer surveillance and consideration of adjuvant therapies.