Automatic Initialization Of Contour For Level Set Algorithms Guided By Integration Of Multiple Views To Segment Abdominal CT Scans

This paper presents a new automatic initialization procedure for a level-set based segmentation algorithm that works on all slices for a given CT dataset

To determine the incidence of post-operative deep vein thrombosis in general surgical patients of Hospital Universiti Sains Malaysia

Apparent rarity of post-operative DVT and pulmonary embolism in Asian patients was first reported since 1964. Very few literature and clinical studies were done for post-operative DVT in Asian population as well as in Malaysia.Compared to the Western hemisphere,low incidence 2.6% to 15.3% was reported from Japan, Hong Kong, Thailand, Singapore and Malaysian studies.Conflicting results of high incidence in orthopaedic patients was reported in two other Asian studies from Hong Kong and Malaysia.To find out the incidence of post-operative deep vein thrombosis (DVT) in our general surgical patients after major surgical procedures.To find out the subgroups of patients at special risk to post-operative DVT.To reviewthe policy of withholding routine DVT prophylaxis in Malaysian patients

Computational fluid dynamics study of pull and plug flow boundary condition on nasal airflow

The recent advances in the computer based computational fluid dynamics (CFD) software tools in the study of airflow behavior in the nasal cavity have opened an entirely new field of medical research. This numerical modeling method has provided both engineers and medical specialists with a clearer understanding of the physics associated with the flow in the complicated nasal domain. The outcome of any CFD investigation depends on the appropriateness of the boundary conditions applied. Most researchers have employed plug boundary condition as against the pull flow which closely resembles the physiological phenomenon associated with the breathing mechanism. A comparative study on the effect of using the plug and pull flow boundary conditions are evaluated and their effect on the nasal flow are studied. Discretization error estimation using Richardson's extrapolation (RE) method has also been carried out. The study is based on the numerical model obtained from computed tomographic data of a healthy Malaysian subject. A steady state Reynold averaged Navier–Stokes and continuity equations is solved for inspiratory flow having flow rate 20 L/min representing turbulent boundary conditions. Comparative study is made between the pull and plug flow model. Variation in flow patterns and flow features such as resistance, pressure and velocity are presented. At the nasal valve, the resistance for plug flow is 0.664 Pa-min/L and for pull flow the value is 0.304 Pa-min/L. The maximum velocity at the nasal valve is 3.28 m/s for plug flow and 3.57 m/s for pull flow model

Review: A critical overview of limitations CFD Modeling in nasal airflow.

Computational fluid dynamics (CFD) modeling of nasal airflow has been carried out by several researchers. Virtual surgical treatment and aerosol deposition studies have also been conducted. However, the appropriateness of such modeling practices with regards to modeling and medical constraints needs careful consideration. The current numerical models for the study of nasal airflow, developed from the scanned images obtained from computed tomography or magnetic resonance imaging, are influenced by postural changes. These models neglect the mucous layer, other vital anatomical features, and nasal cycle effects, CFD studies make numerous assumptions that seriously limit their usefulness. Unless these constraints can be addressed, the interpretation of results from a CFD output cannot be considered as an appropriate definition of the flow behavior. This review provides a critical overview of the limit actions of the CFD mode ling of nasal air-low. Some of the limitations and constraints associated with CFD modeling are reviewed and possible studies that could be carried out in the future to ascertain the effect of neglecting these parameters are discussed. This study also proposes a standard station of the computational modeling procedure, which is necessary for studying airflow inside the nasal cavity

Determination of optimum combination of voxel size and b-value for brain diffusion tensor imaging

Optimum combination of voxel size resolution and b-value for whole brain imaging has been determined. Data images were acquired using a 1.5T magnetic resonance imaging (MRI) system (GE Signa HDxt). Diffusion tensor imaging (DTI) scan was performed on phantom and a human volunteer. Six protocols which consist of various combination of voxel size and b-value were evaluated. Measurement of signal-to-noise ratio (SNR) and DTI parameter indices were carried out for both phantom and in-vivo studies. Due consideration was given to a combination of parameters yielding sufficient SNR with DTI values comparable to those obtained from previous reported studies. For the phantom study, SNR ≥ 20 was found in all of the protocols except for a combination of voxel size of 2.0 × 2.0 × 2.0 mm3 with b-value of 1200 s/mm2 (V2.0 B1200) and that of voxel size of 2.0 × 2.0 × 2.0 mm3 with b-value of 1000 s/mm2 (V2.0 B1000). For in-vivo study, all protocols presented SNR > 20. It was found that a combination of voxel size of 2.5 × 2.5 × 2.5 mm3 with b-value of 1000 s/mm2 (V2.5 B1000) and that of voxel size of 2.5 × 2.5 × 2.5 mm3 with b-value of 700 s/mm2 (V2.5 B700) displayed the most comparable ADC and FA values with references. In terms of anatomic coverage, V2.5 B700 was found better than V2.5 B1000 as it assures coverage of the whole brain. In conclusion, a combination of voxel size of 2.5 × 2.5 × 2.5 mm3 with b-value of 700 s/mm2 was considered as optimum parameters for brain DTI

A Framework of MRI Fat Suppressed Imaging Fusion System for Femur Abnormality Analysis

AbstractShort T1 Inversion Recovery (STIR) is a fat suppressed technique commonly used in Magnetic Resonance Imaging (MRI) to suppress fat signals from tissues. The technique is to improve visual inspection during diagnosis. Suspected fluids will appear bright in STIR to identify the abnormality. Due to hardware limitation, tissue contrast and signal-to-noise ratio are reduced. We propose a framework of image fusion system which mimics the MRI machine to produce a fused ‘STIR’ image. The resultant fused ‘STIR’ image has high similarity index (0.989971), small mean square error (0.1092), high peak signal-to-noise ratio (106.9173) and good Pearson correlation coefficient (0.696)

Diagnostic Cerebral Angiography in Spontaneous Intracranial Haemorrhage: A Guide for Developing Countries

ObjectiveSpontaneous intracranial haemorrhage constitutes 18-40% of all stroke cases. Indications for cerebral angiography to find underlying potentially treatable vascular abnormalities are not clear. This study determined which intracranial haemorrhage patients need cerebral angiography by correlating computed tomography (CT) findings, age and hypertension history with cerebral angiography findings.MethodsA total of 54 patients (8-79 years) with intracranial haemorrhage who underwent both CT examination and six-vessel cerebral angiography were studied over a 2-year period. Cerebral angiography was repeated within 6 weeks if the first angiogram was negative.ResultsAngiography detected vascular lesions in 50% of cases (aneurysm 38.9% and arteriovenous malformation, AVM, 11.1%). In the aneurysm group, angiographic yield was 34.3% whereas in the AVM group, it was 37.9%. Subarachnoid haemorrhage (SAH) combined with other types of haemorrhage (such as intracerebral haemorrhage, ICH) was not significantly correlated with the likelihood of finding a vascular lesion, both aneurysm and AVM (p = 0.157). Age less than 50 years had significant correlation (p = 0.021) in the AVM group as well as in the aneurysm group (p < 0.001). A history of hypertension was associated with both aneurysm (p = 0.039) and AVM (p = 0.008). No patients with deep intracerebral haematoma had vascular lesions. The presence of an intraventricular haemorrhage (IVH) had significant correlation with aneurysm (p = 0.008) but not AVM. There was no significant difference in mean age between patients with and without a vascular lesion (p = 0.134).ConclusionCerebral angiography is justified in patients with pure SAH (p = 0.001). Other factors associated with finding a vascular lesion were a history of hypertension and the presence of IVH. Diagnostic cerebral angiography is indicated for patients with ICH and SAH and IVH with a history of hypertension, regardless of age

The Determination Of Local Malay Female Bone Mineral Density And Its Correlation With Geometric Properties In The Evaluation Of Skeletal Status.

To establish bone mineral density ( BMD ) reference data for local Malay female population and to determine the correlation of BMD and geometric properties Methoelology: A total of 137 Malay female volunteers who have given a written informed consent have undergone DEXA of the spine, dual femur and total body using LUNAR PRODIGY, GE Medical Systems

Analysis of pediatric subdural empyema outcome in relation to computerized tomography brain scan

A cross-sectional study was conducted to predict the outcome in patients with subdural empyema, using initial and post-treatment CT scan brain parameters. Data collection was done on those children who were diagnosed to have subdural empyema by CT scan of the brain with contrast, who underwent burrhole evacuation, from February 2000 until April 2002. Numerous factors, such as coma or loss of unconsciousness at diagnosis, age, types of antibiotic, microbiology, extension of empyema, associated cerebral infarction and ventriculitis, were analyzed. Poor prognosis was associated with loss of consciousness, and hypodensity by CT scan at presentation (p < 0.005). Patients with an extensive subdural empyema will have a good outcome if they are treated early and aggressively with antibiotics and burrhole evacuation