TREATMENT OF HYPOTONY WITH AN INTRAVITREAL GAS BUBBLE.

PURPOSE: To describe a case of successful resolution of severe hypotony and choroidal detachments following nonfiltering glaucoma surgery with an intravitreal injection of C 3 F 8 gas after a poor response to topical steroids and cycloplegia. METHODS: Retrospective chart review of a case report. RESULTS: 89 year-old male presented with a central retinal vein occlusion, hyphema, vitreous hemorrhage and neovascular glaucoma. After initial intravitreal injection of aflibercept he was treated with pars plana vitrectomy with panretinal photocoagulation and endocyclophotocoagulation to the ciliary body, but he continued to have elevated intraocular pressure. Subsequent external cyclophotocoagulation was performed but severe hypotony with inflammation, choroidal detachments, and corneal edema developed one week later without response to cycloplegic and steroid medications. A therapeutic injection of perfluorpropane (C3F8) gas led to resolution of the hypotony and choroid detachment and long-term maintenance of intraocular pressure. DISCUSSION/CONCLUSION: An intravitreal gas bubble can be a very useful outpatient procedure to immediately reverse hypotony, resolve choroidal detachment, and decrease associated inflammation. When hypotony does not respond to medical therapy with cycloplegic drops and steroid medications, then an intravitreal gas bubble can rapidly resolve these complications and result in stabilization of intraocular pressure long-term.

Comparing radiomic classifiers and classifier ensembles for detection of peripheral zone prostate tumors on T2-weighted MRI: a multi-site study.

BACKGROUND: For most computer-aided diagnosis (CAD) problems involving prostate cancer detection via medical imaging data, the choice of classifier has been largely ad hoc, or been motivated by classifier comparison studies that have involved large synthetic datasets. More significantly, it is currently unknown how classifier choices and trends generalize across multiple institutions, due to heterogeneous acquisition and intensity characteristics (especially when considering MR imaging data). In this work, we empirically evaluate and compare a number of different classifiers and classifier ensembles in a multi-site setting, for voxel-wise detection of prostate cancer (PCa) using radiomic texture features derived from high-resolution in vivo T2-weighted (T2w) MRI. METHODS: Twelve different supervised classifier schemes: Quadratic Discriminant Analysis (QDA), Support Vector Machines (SVMs), naïve Bayes, Decision Trees (DTs), and their ensemble variants (bagging, boosting), were compared in terms of classification accuracy as well as execution time. Our study utilized 85 prostate cancer T2w MRI datasets acquired from across 3 different institutions (1 for discovery, 2 for independent validation), from patients who later underwent radical prostatectomy. Surrogate ground truth for disease extent on MRI was established by expert annotation of pre-operative MRI through spatial correlation with corresponding ex vivo whole-mount histology sections. Classifier accuracy in detecting PCa extent on MRI on a per-voxel basis was evaluated via area under the ROC curve. RESULTS: The boosted DT classifier yielded the highest cross-validated AUC (= 0.744) for detecting PCa in the discovery cohort. However, in independent validation, the boosted QDA classifier was identified as the most accurate and robust for voxel-wise detection of PCa extent (AUCs of 0.735, 0.683, 0.768 across the 3 sites). The next most accurate and robust classifier was the single QDA classifier, which also enjoyed the advantage of significantly lower computation times compared to any of the other methods. CONCLUSIONS: Our results therefore suggest that simpler classifiers (such as QDA and its ensemble variants) may be more robust, accurate, and efficient for prostate cancer CAD problems, especially in the context of multi-site validation.

Component alignment after minimally invasive total knee arthroplasty: results of the first 100 cases performed.

It has been suggested that minimally invasive total knee arthroplasties increase the risk of component malalignment. Results during the period of initial learning curve on component malalignment are relatively unknown but should be addressed. This study reports the component alignment data of the first 100 minimally invasive total knee arthroplasties performed by a single surgeon from the very start of a community-based practice immediately after fellowship training. The results indicate that the initial learning curve produces results comparable to reported results of standard total knee arthroplasties.