The Presence of Portal Vein Thrombosis Alters the Classic Enhancement Associated with Diagnosis of Hepatocellular Carcinoma

Digestive Diseases and Sciences - To determine whether the presence of portal vein thrombosis (PVT) where venous flow within the liver may be altered may delay the diagnosis of HCC and be...     

Finite-element models of the human head

A review is presented of the existing finite-element (FE) models for the biomechanics of human head injury. Finite element analysis can be an important tool in describing the injury biomechanics of the human head. Complex geometric and material properties pose challenges to FE modelling. Various assumptions and simplifications are made in model development that require experimental validation. More recent models incorporate anatomic details with higher precision. The cervical vertebral column and spinal cord are included. Model results have been more qualitative than quantitative owing to the lack of adequate experimental validation. Advances include transient stress distribution in the brain tissue, frequency responses, effects of boundary conditions, pressure release mechanism of the foramen magnum and the spinal cord, verification of rotation and cavitation theories of brain injury, and protective effects of helmets. These theoretical results provide a basic understanding of the internal biomechanical responses of the head under various dynamic loading conditions. Basic experimental research is still needed to determine more accurate material properties and injury tolerance criteria, so that FE models can fully exercise their analytical and predictive power for the study and prevention of human head injury.     

Semi-quantitative planar scintigraphy using thallium 201 for detection and localization of coronary artery disease: correlation with coronary angiography.

Thallium 201 exercise redistribution planar myocardial perfusion scan using semiquantitative technique was performed in 80 symptomatic patients undergoing coronary angiography. Out of the 240 vessels studied by angiography, more than 70% luminal narrowing was detected in 87 vessels, borderline stenosis was found in 49 arteries and the remaining 104 vessels were normal. Thallium scan correctly identified the significant stenosis in 76 vessels and the absence of stenosis in 102 vessels. In addition, perfusion abnormality was found in relation with 21 vessels of borderline stenosis. The sensitivity and specificity of Thallium scan were estimated as 92% and 95% for left anterior descending artery (LAD), 79% and 98% for left circumflex artery (LCX), 88% and 100% for right coronary artery (RCA) and 87% and 98% for all coronary arteries combined together (ACA).