Citations

Abstract Channelized Hotelling model observer (CHO) methods were developed to assess performance of an x-ray angiography system. The analytical methods included correction for known bias error due to finite sampling. Detectability indices ( d ′ ) corresponding to disk-shaped objects with diameters in the range 0.5–4 mm were calculated. Application of the CHO for variable detector target dose (DTD) in the range 6–240 nGy frame −1 resulted in d ′ estimates which were as much as 2.9× greater than expected of a quantum limited system. Over-estimation of d ′ < ∼ 3.0 was presumed to be a result of bias error due to temporally variable non-stationary noise. Statistical theory which allows for independent contributions of ‘signal’ from a test object (o) and temporally variable non-stationary noise (ns) was developed. The theory demonstrates that the biased d β ′ is the sum of the detectability indices associated with the test object ( d o ′ ) and non-stationary noise ( d ns ′ ). Given the nature of the imaging system and the experimental methods, d o ′ cannot be directly determined independent of d ns ′ . However, methods to estimate d ns ′ independent of d o ′ were developed. In accordance with the theory, d ns ′ was subtracted from experimental estimates of d β ′ , providing an unbiased estimate of d o ′ . Estimates of d o ′ exhibited trends consistent with expectations of an angiography system that is quantum limited for high DTD and compromised by detector electronic readout noise for low DTD conditions. Results suggest that these methods provide d o ′ estimates which are accurate and precise for d o ′ ⩾ ∼ 1.0 . Further, results demonstrated that the source of bias was detector electronic readout noise. In summary, this work presents theory and methods to test for the presence of bias in Hotelling model observers due to temporally variable non-stationary noise and correct this bias when the temporally variable non-stationary noise is independent and additive with respect to the test object signal.

Lymphoma patients are at increased risk of thromboembolic events but thromboprophylaxis in these patients is largely underused. We sought to develop and validate a simple model, based on individual clinical and laboratory patient characteristics that would designate lymphoma patients at risk for thromboembolic event. The study population included 1,820 lymphoma patients who were treated in the Lymphoma Departments at the Clinics of Hematology, Clinical Center of Serbia and Clinical Center Kragujevac. The model was developed using data from a derivation cohort (n = 1,236), and further assessed in the validation cohort (n = 584). Sixty‐five patients (5.3%) in the derivation cohort and 34 (5.8%) patients in the validation cohort developed thromboembolic events. The variables independently associated with risk for thromboembolism were: previous venous and/or arterial events, mediastinal involvement, BMI>30 kg/m2, reduced mobility, extranodal localization, development of neutropenia and hemoglobin level < 100g/L. Based on the risk model score, the population was divided into the following risk categories: low (score 0‐1), intermediate (score 2‐3), and high (score >3). For patients classified at risk (intermediate and high‐risk scores), the model produced negative predictive value of 98.5%, positive predictive value of 25.1%, sensitivity of 75.4%, and specificity of 87.5%. A high‐risk score had positive predictive value of 65.2%. The diagnostic performance measures retained similar values in the validation cohort. Developed prognostic Thrombosis Lymphoma – ThroLy score is more specific for lymphoma patients than any other available score targeting thrombosis in cancer patients. Am. J. Hematol. 91:1014–1019, 2016. © 2016 Wiley Periodicals, Inc.

Purpose According to the lung cancer staging project, T1a (≤ 2 cm) non–small-cell lung cancer (NSCLC) should be additionally classified into ≤ 1 cm and > 1 to 2 cm groups. This study aimed to investigate the surgical procedure for NSCLC ≤ 1 cm and > 1 to 2 cm. Methods We identified 15,760 patients with T1aN0M0 NSCLC after surgery from the Surveillance, Epidemiology, and End Results database. Overall survival (OS) and lung cancer–specific survival (LCSS) were compared among patients after lobectomy, segmentectomy, or wedge resection. The proportional hazards model was applied to evaluate multiple prognostic factors. Results OS and LCSS favored lobectomy compared with segmentectomy or wedge resection in patients with NSCLC ≤ 1 cm and > 1 to 2 cm. Multivariable analysis showed that segmentectomy and wedge resection were independently associated with poorer OS and LCSS than lobectomy for NSCLC ≤ 1 cm and > 1 to 2 cm. With sublobar resection, lower OS and LCSS emerged for NSCLC > 1 to 2 cm after wedge resection, whereas similar survivals were observed for NSCLC ≤ 1 cm. Multivariable analyses showed that wedge resection is an independent risk factor of survival for NSCLC > 1 to 2 cm but not for NSCLC ≤ 1 cm. Conclusion Lobectomy showed better survival than sublobar resection for patients with NSCLC ≤ 1 cm and > 1 to 2 cm. For patients in whom lobectomy is unsuitable, segmentectomy should be recommended for NSCLC > 1 to 2 cm, whereas surgeons could rely on surgical skills and the patient profile to decide between segmentectomy and wedge resection for NSCLC ≤ 1 cm.

Objective To assess the feasibility of using MicroFil polymer perfusion to detect concomitant saccular aneurysms in an intracranial arterial dolichoectasia (IADE) model in mice, and to report detailed histomorphometric features of these aneurysms. Materials and methods IADE models were created in C57/BL6 mice via microsurgical injection of 25 mU elastase into the cisterna magna. The cerebral vasculature was perfused with MicroFil polymer and harvested at 1, 3, and 7 days, and 2 and 4 weeks (n=8 for each group). IADE was defined by a tortuosity index >10 combined with a 25% increase in diameter of the A1 segment of the anterior cerebral artery (ACA), internal carotid artery (ICA), or basilar artery compared with the baseline of controls, which received heat-inactivated elastase. Saccular aneurysm occurrence rate, location, and morphological parameters were investigated using macroscopic and microscopic analysis. Results IADE was present in 95% (36/38) of the subjects, with a mortality rate of 5% (2/40). Fifteen concomitant saccular aneurysms were detected in 8 (21%) of the 38 surviving mice, including 6 at the posterior communicating artery, 1 along the ACA, 2 along the anterior communicating artery complex, 3 along the ICA, and 3 along the middle cerebral artery. Rupture was confirmed in two aneurysms. Histological examination indicated that the aneurysms develop via arterial-wall remodelling, which is characterized by internal elastic lamina disruptions and muscular layer discontinuity in the media. Conclusions The proportion of subjects developing saccular aneurysms in addition to IADE in our mouse model is similar to the 15% of patients with IADE who have concomitant saccular aneurysms.

Although not yet ready for clinical application, methods based on Raman spectroscopy have shown significant potential in identifying, characterizing, and discriminating between noncancerous and cancerous specimens. Real-time and accurate medical diagnosis achievable through this vibrational optical method largely benefits from improvements in current technological and software capabilities. Not only is the acquisition of spectral information now possible in milliseconds and analysis of hundreds of thousands of data points achieved in minutes, but Raman spectroscopy also allows simultaneous detection and monitoring of several biological components. Besides demonstrating a significant Raman signature distinction between nontumorigenic (MCF-10A) and tumorigenic (MCF-7) breast epithelial cells, our study demonstrates that Raman can be used as a label-free method to evaluate epidermal growth factor activity in tumor cells. Comparative Raman profiles and images of specimens in the presence or absence of epidermal growth factor show important differences in regions attributed to lipid, protein, and nucleic acid vibrations. The occurrence, which is dependent on the presence of epidermal growth factor, of new Raman features associated with the appearance of phosphothreonine and phosphoserine residues reflects a signal transduction from the membrane to the nucleus, with concomitant modification of DNA/RNA structural characteristics. Parallel Western blotting analysis reveals an epidermal growth factor induction of phosphorylated Akt protein, corroborating the Raman results. The analysis presented in this work is an important step toward Raman-based evaluation of biological activity of epidermal growth factor receptors on the surfaces of breast cancer cells. With the ultimate future goal of clinically implementing Raman-guided techniques for the diagnosis of breast tumors (e.g., with regard to specific receptor activity), the current results just lay the foundation for further label-free optical tools to diagnose the disease.