An optimization based on simulation approach to the patient admission scheduling problem: diagnostic imaging department case study.

The growing influx of patients in healthcare providers is the result of an aging population and emerging self-consciousness about health. In order to guarantee the welfare of all the healthcare stakeholders, it is mandatory to implement methodologies that optimize the healthcare providers' efficiency while increasing patient throughput and reducing patient's total waiting time. This paper presents a case study of a conventional radiology workflow analysis in a Portuguese healthcare provider. Modeling tools were applied to define the existing workflow. Re-engineered workflows were analyzed using the developed simulation tool. The integration of modeling and simulation tools allowed the identification of system bottlenecks. The new workflow of an imaging department entails a reduction of 41 % of the total completion time.

3D lacunarity in multifractal analysis of breast tumor lesions in dynamic contrast-enhanced magnetic resonance imaging.

Dynamic contrast-enhanced magnetic resonance (DCE-MR) of the breast is especially robust for the diagnosis of cancer in high-risk women due to its high sensitivity. Its specificity may be, however, compromised since several benign masses take up contrast agent as malignant lesions do. In this paper, we propose a novel method of 3D multifractal analysis to characterize the spatial complexity (spatial arrangement of texture) of breast tumors at multiple scales. Self-similar properties are extracted from the estimation of the multifractal scaling exponent for each clinical case, using lacunarity as the multifractal measure. These properties include several descriptors of the multifractal spectra reflecting the morphology and internal spatial structure of the enhanced lesions relatively to normal tissue. The results suggest that the combined multifractal characteristics can be effective to distinguish benign and malignant findings, judged by the performance of the support vector machine classification method evaluated by receiver operating characteristics with an area under the curve of 0.96. In addition, this paper confirms the presence of multifractality in DCE-MR volumes of the breast, whereby multiple degrees of self-similarity prevail at multiple scales. The proposed feature extraction and classification method have the potential to complement the interpretation of the radiologists and supply a computer-aided diagnosis system.

Impact of peginterferon alpha-2b and ribavirin treatment on liver tissue in patients with HCV or HCV-HIV co-infection.

OBJECTIVE: To evaluate the effect of treatment with peginterferon alpha-2b and ribavirin on liver histology in patients with chronic hepatitis C (CHC) with or without HIV infection. METHODS: Patients received peginterferon alpha-2b (1.5 micro/kg/week during the first 4 weeks; 1.0 micro/kg/week thereafter) plus ribavirin (800-1200 mg/day, adjusted for weight) for 24 (genotypes 2/3) or 48 weeks (genotypes 1/4). Paired liver biopsy specimens were obtained at baseline and at the end of follow-up. RESULTS: 108 paired biopsy specimens were available: 67 from HCV-monoinfected and 41 from co-infected patients. At the end of follow-up, necroinflammatory activity (NIA) was significantly reduced (P<0.001), and fibrosis scores improved by > or = 1 point (Ishak et al criteria) in 65.7% of HCV-monoinfected patients. In co-infected patients, NIA was significantly reduced (P<0.001), and fibrosis scores improved by > or = 1 point in 42.5% of cases. In both groups, results were better for patients who attained sustained virological response (SVR). HCV RNA was undetectable in the second biopsy specimens of all patients who attained SVR. CONCLUSION: Liver fibrosis is reduced significantly after a course of therapy in patients with chronic hepatitis C. Reduction of fibrosis is more significant in patients who are monoinfected with HCV and in those who attained SVR.