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BACKGROUND: A major driver of individual variation in long-term outcomes following a large vessel occlusion (LVO) stroke is the degree of collateral arterial circulation. We aimed to develop and evaluate machine-learning models that quantify LVO collateral status using admission computed tomography angiography (CTA) radiomics. METHODS: We extracted 1116 radiomic features from the anterior circulation territories from admission CTAs of 600 patients experiencing an acute LVO stroke. We trained and validated multiple machine-learning models for the prediction of collateral status based on consensus from two neuroradiologists as ground truth. Models were first trained to predict (1) good vs. intermediate or poor, or (2) good vs. intermediate or poor collateral status. Then, model predictions were combined to determine a three-tier collateral score (good, intermediate, or poor). We used the receiver operating characteristics area under the curve (AUC) to evaluate prediction accuracy. RESULTS: We included 499 patients in training and 101 in an independent test cohort. The best-performing models achieved an averaged cross-validation AUC of 0.80 ± 0.05 for poor vs. intermediate/good collateral and 0.69 ± 0.05 for good vs. intermediate/poor, and AUC = 0.77 (0.67-0.87) and AUC = 0.78 (0.70-0.90) in the independent test cohort, respectively. The collateral scores predicted by the radiomics model were correlated with (rho = 0.45, p = 0.002) and were independent predictors of 3-month clinical outcome (p = 0.018) in the independent test cohort. CONCLUSIONS: Automated tools for the assessment of collateral status from admission CTA-such as the radiomics models described here-can generate clinically relevant and reproducible collateral scores to facilitate a timely treatment triage in patients experiencing an acute LVO stroke.
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Background: Although response in pediatric low-grade glioma (pLGG) includes volumetric assessment, more simplified 2D-based methods are often used in clinical trials. The study's purpose was to compare volumetric to 2D methods. Methods: An expert neuroradiologist performed solid and whole tumor (including cyst and edema) volumetric measurements on MR images using a PACS-based manual segmentation tool in 43 pLGG participants (213 total follow-up images) from the Pacific Pediatric Neuro-Oncology Consortium (PNOC-001) trial. Classification based on changes in volumetric and 2D measurements of solid tumor were compared to neuroradiologist visual response assessment using the Brain Tumor Reporting and Data System (BT-RADS) criteria for a subset of 65 images using receiver operating characteristic (ROC) analysis. Longitudinal modeling of solid tumor volume was used to predict BT-RADS classification in 54 of the 65 images. Results: There was a significant difference in ROC area under the curve between 3D solid tumor volume and 2D area (0.96 vs 0.78, P = .005) and between 3D solid and 3D whole volume (0.96 vs 0.84, P = .006) when classifying BT-RADS progressive disease (PD). Thresholds of 15-25% increase in 3D solid tumor volume had an 80% sensitivity in classifying BT-RADS PD included in their 95% confidence intervals. The longitudinal model of solid volume response had a sensitivity of 82% and a positive predictive value of 67% for detecting BT-RADS PD. Conclusions: Volumetric analysis of solid tumor was significantly better than 2D measurements in classifying tumor progression as determined by BT-RADS criteria and will enable more comprehensive clinical management.
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Background: Treatment of brain metastases can be tailored to individual lesions with treatments such as stereotactic radiosurgery. Accurate surveillance of lesions is a prerequisite but challenging in patients with multiple lesions and prior imaging studies, in a process that is laborious and time consuming. We aimed to longitudinally track several lesions using a PACS-integrated lesion tracking tool (LTT) to evaluate the efficiency of a PACS-integrated lesion tracking workflow, and characterize the prevalence of heterogenous response (HeR) to treatment after Gamma Knife (GK). Methods: We selected a group of brain metastases patients treated with GK at our institution. We used a PACS-integrated LTT to track the treatment response of each lesion after first GK intervention to maximally seven diagnostic follow-up scans. We evaluated the efficiency of this tool by comparing the number of clicks necessary to complete this task with and without the tool and examined the prevalence of HeR in treatment. Results: A cohort of eighty patients was selected and 494 lesions were measured and tracked longitudinally for a mean follow-up time of 374 days after first GK. Use of LTT significantly decreased number of necessary clicks. 81.7% of patients had HeR to treatment at the end of follow-up. The prevalence increased with increasing number of lesions. Conclusions: Lesions in a single patient often differ in their response to treatment, highlighting the importance of individual lesion size assessments for further treatment planning. PACS-integrated lesion tracking enables efficient lesion surveillance workflow and specific and objective result reports to treating clinicians.
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INTRODUCTION: 25 (OH) vitamin D plays an important role in many places through the body. Its deficien- cy can cause rickets or osteomalacia. This is particularly im- portant in hemodialysis (HD) patients who are at icreased risk due to decreased sunlight exposure and deterioration of their mineral homeostasis. OBJECTIVES: To determine the prevalence of 25 (OH) vitamin D deficiency in HD patients at Rafic Hariri University Hospital (RHUH), compared to a sample of the general population matched for gender and age, and to evaluate the effectiveness of 25 (OH) vitamin D supplementation in HD deficient group. METHODS: This is a cross sectional study conducted since December 2012, comparing the prevalence of 25 (OH) vitamin D deficiency in HD patients in the dialysis center at RHUH, with patients from the general population who sought medical attention at RHUH for purposes other than HD, matched for age and gender. 25 (OH) vitamin D levels were measured with radio- immunoassay method (LOINC) at CIC European Lab, Bar- celona, Spain. A pilot study was conducted with the 34 HD patients who turned out to be deficient or insufficient in 25 (OH) vitamin D. We supplemented them with cholecalciferol over 6 months. We then assessed their vitamin D levels, and biochemistry parameters. RESULTS: The prevalence of 25 (OH) vitamin D deficiency in the sample of HD patients at baseline was 32% while that of insufficiency was 36%. The prevalence of 25 (OH) vitamin D deficiency in the sample of general population was 67%. No correlation was found be- tween 25 (OH) vitamin D levels and the studied parameters. In the pilot study, after six months of cholecalciferol supple- mentation, there was a significant improvement in 25 (OH) vitamin D levels in the deficient and insufficient groups. CONCLUSION: The sample studied in the general population showed high prevalence of 25 (OH) vitamin D deficiency (67%). The sample studied in HD patients showed a preva- lence of 25 (OH) vitamin D deficiency of 32% and insuffi- ciency of 36%. The pilot study showed that 25 (OH) vitamin D supplementation in the form of cholecalciferol is beneficial in HD patients.
