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Measuring tissue sodium concentration: Cross-vendor repeatability and reproducibility of 23 Na-MRI across two sites.
Riemer, F, McHugh, D, Zaccagna, F, Lewis, D, McLean, MA, Graves, MJ, Gilbert, FJ, Parker, GJM, Gallagher, FA
Journal of magnetic resonance imaging : JMRI. 2019;(4):1278-1284
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Abstract
BACKGROUND Sodium MRI (23 Na-MRI)-derived biomarkers such as total sodium concentration (TSC) have the potential to provide information on tumor cellularity and the changes in tumor microstructure that occur following therapy. PURPOSE To evaluate the repeatability and reproducibility of TSC measurements in the brains of healthy volunteers, providing evidence for the technical validation of 23 Na-MRI-derived biomarkers. STUDY TYPE Prospective multicenter study. SUBJECTS Eleven volunteers (32 ± 6 years; eight males, three females) were scanned twice at each of two sites. FIELD STRENGTH/SEQUENCE Comparable 3D-cones 23 Na-MRI ultrashort echo time acquisitions at 3T. ASSESSMENT TSC values, quantified from calibration phantoms placed in the field of view, were obtained from white matter (WM), gray matter (GM), and cerebrospinal fluid (CSF), based on automated segmentation of coregistered 1 H T1 -weighted images and hand-drawn regions of interest by two readers. STATISTICAL TESTS Coefficients of variation (CoVs) from mean TSC values were used to assess intrasite repeatability and intersite reproducibility. RESULTS Mean GM TSC concentrations (52.1 ± 7.1 mM) were ∼20% higher than for WM (41.8 ± 6.7 mM). Measurements were highly repeatable at both sites with mean scan-rescan CoVs between volunteers and regions of 2% and 4%, respectively. Mean intersite reproducibility CoVs were 3%, 3%, and 6% for WM, GM, and CSF, respectively. DATA CONCLUSION These results demonstrate technical validation of sodium MRI-derived biomarkers in healthy volunteers. We also show that comparable 23 Na imaging of the brain can be implemented across different sites and scanners with excellent repeatability and reproducibility. LEVEL OF EVIDENCE 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:1278-1284.
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Analysis of Discrepancy Between Diagnostic Clinical Examination Findings and Corresponding Evaluation of Digital Images in the Telemedicine Approaches to Evaluating Acute-Phase Retinopathy of Prematurity Study.
Quinn, GE, Ells, A, Capone, A, Hubbard, GB, Daniel, E, Hildebrand, PL, Ying, GS, ,
JAMA ophthalmology. 2016;(11):1263-1270
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Abstract
IMPORTANCE As effective treatments for potentially blinding retinopathy of prematurity (ROP) have been introduced, the importance of consistency in findings has increased, especially with the shift toward retinal imaging in infants at risk of ROP. OBJECTIVE To characterize discrepancies in findings of ROP between digital retinal image grading and examination results from the Telemedicine Approaches to Evaluating Acute-Phase Retinopathy of Prematurity study, conducted from May 2011 to October 2013. DESIGN, SETTING, AND PARTICIPANTS A poststudy consensus review of images was conducted by 4 experts, who examined discrepancies in findings between image grades by trained nonphysician readers and physician examination results in infants with referral-warranted ROP (RW-ROP). Images were obtained from 13 North American neonatal intensive care units from eyes of infants with birth weights less than 1251 g. For discrepancy categories with more than 100 cases, 40 were randomly selected; in total, 188 image sets were reviewed. MAIN OUTCOMES AND MEASURES Consensus evaluation of discrepant image and examination findings for RW-ROP components. RESULTS Among 5350 image set pairs, there were 161 instances in which image grading did not detect RW-ROP noted on clinical examination (G-/E+) and 854 instances in which grading noted RW-ROP when the examination did not (G+/E-). Among the sample of G-/E+ cases, 18 of 32 reviews (56.3%) agreed with clinical examination findings that ROP was present in zone I and 18 of 40 (45.0%) agreed stage 3 ROP was present, but only 1 of 20 (5.0%) agreed plus disease was present. Among the sample of G+/E- cases, 36 of 40 reviews (90.0%) agreed with readers that zone I ROP was present, 23 of 40 (57.5%) agreed with readers that stage 3 ROP was present, and 4 of 16 (25.0%) agreed that plus disease was present. Based on the consensus review results of the sampled cases, we estimated that review would agree with clinical examination findings in 46.5% of the 161 G-/E+ cases (95% CI, 41.6-51.6) and agree with trained reader grading in 70.0% of the 854 G+/E- cases (95% CI, 67.3-72.8) for the presence of RW-ROP. CONCLUSIONS AND RELEVANCE This report highlights limitations and strengths of both the remote evaluation of fundus images and bedside clinical examination of infants at risk for ROP. These findings highlight the need for standardized approaches as ROP telemedicine becomes more widespread.
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Comparison of digital and film grading of diabetic retinopathy severity in the diabetes control and complications trial/epidemiology of diabetes interventions and complications study.
Hubbard, LD, Sun, W, Cleary, PA, Danis, RP, Hainsworth, DP, Peng, Q, Susman, RA, Aiello, LP, Davis, MD, ,
Archives of ophthalmology (Chicago, Ill. : 1960). 2011;(6):718-26
Abstract
OBJECTIVE To compare diabetic retinopathy (DR) severity as evaluated by digital and film images in a long-term multicenter study, as the obsolescence of film forced the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study (DCCT/EDIC) to transition to digital after 25 years. METHODS At 20 clinics from 2007 through 2009, 310 participants with type 1 diabetes with a broad range of DR were imaged, per the Early Treatment Diabetic Retinopathy Study (ETDRS) protocol, with both film and digital cameras. Severity of DR was assessed centrally from film and tonally standardized digital cameras. For retinopathy outcomes with greater than 10% prevalence, we had 85% or greater power to detect an agreement κ of 0.7 or lower from our target of 0.9. RESULTS Comparing DR severity, digital vs film yielded a weighted κ of 0.74 for eye level and 0.73 for patient level ("substantial"). Overall, digital grading did not systematically underestimate or overestimate severity (McNemar bias test, P = .14). For major DR outcomes (≥3-step progression on the ETDRS scale and disease presence at ascending thresholds), digital vs film κ values ranged from 0.69 to 0.96 ("substantial" to "nearly perfect"). Agreement was 86% to 99%; sensitivity, 75% to 98%; and specificity, 72% to 99%. Major conclusions were similar with digital vs film gradings (odds reductions with intensive diabetes therapy for proliferative DR at EDIC years 14 to 16: 65.5% digital vs 64.3% film). CONCLUSION Digital and film evaluations of DR were comparable for ETDRS severity levels, DCCT/EDIC design outcomes, and major study conclusions, indicating that switching media should not adversely affect ongoing studies.
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Impact of olmesartan on progression of coronary atherosclerosis a serial volumetric intravascular ultrasound analysis from the OLIVUS (impact of OLmesarten on progression of coronary atherosclerosis: evaluation by intravascular ultrasound) trial.
Hirohata, A, Yamamoto, K, Miyoshi, T, Hatanaka, K, Hirohata, S, Yamawaki, H, Komatsubara, I, Murakami, M, Hirose, E, Sato, S, et al
Journal of the American College of Cardiology. 2010;(10):976-82
Abstract
OBJECTIVES The aim of this study was to evaluate the impact of olmesartan on progression of coronary atherosclerosis. BACKGROUND Prior intravascular ultrasound (IVUS) trial results suggest slowing of coronary atheroma progression with some medicines but have not shown convincing evidence of regression with angiotension-II receptor blocking agents. METHODS A prospective, randomized, multicenter trial-OLIVUS (Impact of OLmesartan on progression of coronary atherosclerosis: evaluation by IntraVascular UltraSound)-was performed in 247 stable angina pectoris patients with native coronary artery disease. When these patients underwent percutaneous coronary intervention for culprit lesions, IVUS was performed in their nonculprit vessels (without angiographically documented coronary stenosis [<50%]). Patients were randomly assigned to receive 10 to 40 mg of olmesartan or control and treated with a combination of beta-blockers, calcium channel blockers, diuretics, nitrates, glycemic control agents, and/or statins per physician's guidance. Serial IVUS examinations (baseline and 14-month follow-up) were performed to assess coronary atheroma volume. Volumetric IVUS analyses included lumen, plaque, vessel volume, percent atheroma volume (PAV), percent change in total atheroma volume (TAV) and PAV. RESULTS Patient characteristics and blood pressure control were identical between the 2 groups. However, follow-up IVUS showed significantly decreased TAV and percent change in PAV in the olmesartan group (5.4% vs. 0.6 % for TAV and 3.1% vs. -0.7% for percent change in PAV, control vs. olmesartan, p < 0.05 for all). CONCLUSIONS These observations suggest a positive role in a potentially lower rate of coronary atheroma progression through the administration of olmesartan, an angiotension-II receptor blocking agent, for patients with stable angina pectoris.