Diagnostic Performance of 64-Channel Multislice Computed Tomography in Assessment of Significant Coronary Artery Disease in Symptomatic Subjects

The recent development of 64-channel multislice computed tomography (MSCT) has resulted in noninvasive coronary artery imaging improvement. This study was conducted to determine the accuracy of 64-slice MSCT in a relatively unselected group of 143 patients with presentations suggestive of coronary artery disease, including those with unstable angina pectoris, who underwent both coronary computed tomographic angiography and invasive coronary angiography. No arrhythmia was considered an exclusion criterion except for atrial fibrillation or frequent extrasystoles. In patients with fast heart rates, a β blocker was administered orally. Data were obtained using electrocardiography gated 64-slice MSCT. Computed tomographic angiography and invasive coronary angiography findings of each coronary segment were compared to determine the sensitivity, specificity, positive predictive value, and negative predictive value of MSCT in the detection of their normalcy or insignificant (<50 diameter decrease) stenosis versus significant (�50 diameter decrease) stenosis or total occlusion. In per-patient assessment, the calculated sensitivity, specificity, positive predictive value, and negative predictive value of MSCT were 96, 67, 91, and 83, respectively. These values in per-artery evaluation were 94, 94, 87, and 97, and corresponding values in per-segment analysis were 92, 97, 77, and 99, respectively. In conclusion, computed tomographic angiography has high diagnostic performance in the assessment of significant coronary artery disease in most patients in a daily routine practice, including those presenting with unstable angina pectoris symptoms. © 2007 Elsevier Inc. All rights reserved

Identification of New Alleles and the Determination of Alleles and Genotypes Frequencies at the CYP2D6 Gene in Emiratis

CYP2D6 belongs to the cytochrome P450 superfamily of enzymes and plays an important role in the metabolism of 20–25% of clinically used drugs including antidepressants. It displays inter-individual and inter-ethnic variability in activity ranging from complete absence to excessive activity which causes adverse drug reactions and toxicity or therapy failure even at normal drug doses. This variability is due to genetic polymorphisms which form poor, intermediate, extensive or ultrarapid metaboliser phenotypes. This study aimed to determine CYP2D6 alleles and their frequencies in the United Arab Emirates (UAE) local population. CYP2D6 alleles and genotypes were determined by direct DNA sequencing in 151 Emiratis with the majority being psychiatric patients on antidepressants. Several new alleles have been identified and in total we identified seventeen alleles and 49 genotypes. CYP2D6*1 (wild type) and CYP2D6*2 alleles (extensive metaboliser phenotype) were found with frequencies of 39.1% and 12.2%, respectively. CYP2D6*41 (intermediate metaboliser) occurred in 15.2%. Homozygous CYP2D6*4 allele (poor metaboliser) was found with a frequency of 2% while homozygous and heterozygous CYP2D6*4 occurred with a frequency of 9%. CYP2D6*2xn, caused by gene duplication (ultrarapid metaboliser) had a frequency of 4.3%. CYP2D6 gene duplication/multiduplication occurred in 16% but only 11.2% who carried more than 2 active functional alleles were considered ultrarapid metabolisers. CYP2D6 gene deletion in one copy occurred in 7.5% of the study group. In conclusion, CYP2D6 gene locus is heterogeneous in the UAE national population and no significant differences have been identified between the psychiatric patients and controls

The effect of arterial wall deformability on hemodynamics of CABG

In this study, hemodynamic forces in a threedimensional (3D) computational model of Coronary Artery Bypass Grafting (CABG) with deformable and rigid walls were compared. A physiologic pulsatile non-Newtonian blood flow was considered in the arteries for both models. The artery walls in the distensible model were considered to be hyper-elastic with nonlinear strain dependent Young’s module and axial and radial degrees of freedom, while the deformability in all directions of the rigid model was restricted. The velocity distributions and magnitudes, vortex motions and the occurrence of recirculation zones were selected as the primary hemodynamic parameters in order to show the effect of deformability in the arterial wall and in calculating differences versus the rigid wall model. It was found that during systolic, the velocity magnitude at the host artery bed could vary by up to 80% depending on the longitudinal distance from the center of the anastomosis junction

Design and fabrication of reconstructive mandibular models using fused deposition modeling

Combination of advanced imaging, designing and manufacturing techniques has been rapidly developed in recent years for diagnostic and therapeutic purposes for medical devices. The purpose of this paper is to present a methodology for design and fabrication procedure of medical models using computer-aided design (CAD) and fused deposition modeling (FDM) technique for application in the mandibular reconstructive surgery. Case studies of patients with mandibular defects are examined using CAD model construction including data acquisition from computerized tomography scan and data processing. Furthermore, the effect of advanced manufacturing parameters settings in FDM methodology is investigated. The models were used in assisting the surgeons in their reconstruction planning. A significant improvement regarding the success and convenience in surgery planning been reported. This paper explores the application and viability of FDM rapid prototyping technology for fabrication of complex mandibular models used for reconstructive surgery