Background and Purpose-Different definitions have been proposed to define the ischemic penumbra from perfusion-CT (PCT) data, based on parameters and thresholds tested only in small pilot studies. The purpose of this study was to perform a systematic evaluation of all PCT parameters (cerebral blood flow, volume [CBV], mean transit time [MTT], time-to-peak) in a large series of acute stroke patients, to determine which (combination of) parameters most accurately predicts infarct and penumbra. Methods-One hundred and thirty patients with symptoms suggesting hemispheric stroke Յ12 hours from onset were enrolled in a prospective multicenter trial. They all underwent admission PCT and follow-up diffusion-weighted imaging/fluid-attenuated inversion recovery (DWI/FLAIR); 25 patients also underwent admission DWI/FLAIR. PCT maps were assessed for absolute and relative reduced CBV, reduced cerebral blood flow, increased MTT, and increased time-to-peak. Receiver-operating characteristic curve analysis was performed to determine the most accurate PCT parameter, and the optimal threshold for each parameter, using DWI/FLAIR as the gold standard. Results-The PCT parameter that most accurately describes the tissue at risk of infarction in case of persistent arterial occlusion is the relative MTT (area under the curveϭ0.962), with an optimal threshold of 145%. The PCT parameter that most accurately describes the infarct core on admission is the absolute CBV (area under the curveϭ0.927), with an optimal threshold at 2.0 mlϫ100 g

The goal of this study was to develop a technique to distinguish benign and malignant breast lesions in secondarily digitized mammograms. A set of 51 mammograms (two views/patient) containing lesions of known pathology were evaluated using six different morphological descriptors: circularity, mu R/sigma R (where mu R = mean radial distance of tumor boundary, sigma R = standard deviation); compactness, P2/A (where P = perimeter length of tumor boundary and A = area of the tumor); normalized moment classifier; fractal dimension; and a tumor boundary roughness (TBR) measurement (the number of angles in the tumor boundary with more than one boundary point divided by the total number of angles in the boundary). The lesion was segmented from the surrounding background using an adaptive region growing technique. Ninety-seven percent of the lesions were segmented using this approach. An ROC analysis was performed for each parameter and the results of this analysis were compared to each other and to those obtained from a subjective review by two board-certified radiologists who specialize in mammography. The results of the analysis indicate that all six parameters are diagnostic for malignancy with areas under their ROC curves ranging from 0.759 to 0.928. We observed a trend towards increased specificity at low false-negative rates (0.01 and 0.001) with the TBR measurement. Additionally, the diagnostic accuracy of a classification model based on this parameter was similar to that of the subjective reviewers.

BACKGROUND AND PURPOSE:The Patlak model has been applied to first-pass perfusion CT (PCT) data to extract information on blood-brain barrier permeability (BBBP) to predict hemorrhagic transformation in patients with acute stroke. However, the Patlak model was originally described for the delayed steady-state phase of contrast circulation. The goal of this study was to assess whether the first pass or the delayed phase of a contrast bolus injection better respects the assumptions of the Patlak model for the assessment of BBBP in patients with acute stroke by using PCT.

Introduction: Despite healthcare reforms mandating expanded insurance coverage and reduced out-of-pocket costs for preventive care, cancer screening rates remain relatively static. No study has measured cancer screening rates for multiple tests among non-Medicare patients. Methods: This retrospective, population-based claims analysis, conducted in 2016−2017, of commercially insured and Medicaid-insured women aged 30−59 years enrolled in IBM MarketScan Commercial and Medicaid Databases (containing approximately 90 and 17 million enrollees, respectively) during 2010−2015 describes screening rates for breast, cervical, and colorectal cancer. Key outcomes were (1) proportion screened for breast, cervical, and colorectal cancer among the age-eligible population compared with accepted age-based recommendations and (2) proportion with longer-than-recommended intervals between tests. Results: One half (54.7%) of commercially insured women aged 40−59 years (n=1,538,444) were screened three or more times during the 6-year study period for breast cancer; for Medicaid-insured women (n=78,897), the rates were lower (23.7%). One third (43.4%) of commercially insured and two thirds (68.9%) of Medicaid-insured women had a >2.5-year gap between mammograms. Among women aged 30−59 years, 59.3% of commercially insured women and 31.4% of Medicaidinsured women received two or more Pap tests. The proportion of patients with a >3.5-year gap between Pap tests was 33.9% (commercially insured) and 57.1% (Medicaid-insured). Among women aged 50−59 years, 63.3% of commercially insured women and 47.2% of Medicaid-insured women were screened at least one time for colorectal cancer. Almost all women aged 30−59 years (commercially insured, 99.1%; Medicaid-insured, 98.9%) had at least one healthcare encounter. Conclusions: Breast and cervical cancer screenings remain underutilized among both commercially insured and Medicaid-insured populations, with lower rates among the Medicaid-insured population. However, almost all women had at least one healthcare encounter, suggesting opportunities for better coordinated care.