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Biomedical subjects

Jafar Golzarian

Publications and source records attributed to Jafar Golzarian.

13 recordsLinked to original sources
PubMed2006

Nonvariceal upper gastrointestinal bleeding.

Nonvariceal upper gastrointestinal bleeding (NUGB) remains a major medical problem even after advances in medical therapy with gastric acid suppression and cyclooxygenase (COX-2) inhibitors. Although the incidence of upper gastrointestinal bleeding presenting to the emergency room has slightly decreased, similar decreases in overall mortality and rebleeding rate have not been experienced over the last few decades. Many causes of upper gastrointestinal bleeding have been identified and will be reviewed. Endoscopic, radiographic and angiographic modalities continue to form the basis of the diagnosis of upper gastrointestinal bleeding with new research in the field of CT angiography to diagnose gastrointestinal bleeding. Endoscopic and angiographic treatment modalities will be highlighted, emphasizing a multi-modality treatment plan for upper gastrointestinal bleeding.

Angiography↗
PubMed2006

Bolus characteristics based on Magnetic Resonance Angiography.

BACKGROUND: A detailed contrast bolus propagation model is essential for optimizing bolus-chasing Computed Tomography Angiography (CTA). Bolus characteristics were studied using bolus-timing datasets from Magnetic Resonance Angiography (MRA) for adaptive controller design and validation. METHODS: MRA bolus-timing datasets of the aorta in thirty patients were analyzed by a program developed with MATLAB. Bolus characteristics, such as peak position, dispersion and bolus velocity, were studied. The bolus profile was fit to a convolution function, which would serve as a mathematical model of bolus propagation in future controller design. RESULTS: The maximum speed of the bolus in the aorta ranged from 5-13 cm/s and the dwell time ranged from 7-13 seconds. Bolus characteristics were well described by the proposed propagation model, which included the exact functional relationships between the parameters and aortic location. CONCLUSION: The convolution function describes bolus dynamics reasonably well and could be used to implement the adaptive controller design.

Computer Simulation↗
PubMed2006

Endoleakage after endovascular treatment of abdominal aortic aneurysms: Diagnosis, significance and treatment.

Endoleak, also called leakage, leak and Perigraft leak, is a major complication and its persistence represents a failure of endovascular aortic aneurysm repair. Its detection and treatment is therefore of primary importance, since endoleak can be associated with pressurization (increase in pressure) of the sac, resulting in expansion and rupture of the aneurysm. The aim of this paper is to discuss the definition, significance, diagnosis and different options to treat endoleak.

Aortic Aneurysm, Abdominal↗
PubMed2005

Introduction to biomechanics related to endovascular repair of abdominal aortic aneurysm.

Biomechanical issues of practical relevance to the physician in the clinical management of patients undergoing endovascular repair (EVR) of their abdominal aortic aneurysms (AAA) is discussed. Following a brief description of key terms in vascular biomechanics, background on the current state of knowledge in the biomechanics of AAA pathogenesis and rupture is provided. This is followed by a discussion of key issues of biomechanical relevance in EVR such as the mechanics of endotension, the notion of intraaneurysmal sac pressure and potential pitfalls of techniques used to measure them, mechanics of graft fracture/kinking, and graft migration. The discussions are intended to provide an overview of this field to physicians.

Aortic Aneurysm, Abdominal↗
PubMed2005

Endoleak: treatment options.

Endoleak, also called leakage, leak, and Perigraft leak, is a major complication and its persistence represents a failure of endovascular aortic aneurysm repair (EVAR). Its detection and treatment is therefore of primary importance since endoleak is associated with pressurization (increases pressure) of the sac, resulting in expansion and rupture of the aneurysm. The aim of this article was to discuss the different options to treat endoleak.

Aortic Aneurysm, Abdominal↗
PubMed2003

Original report. Late myocardial enhancement in hypertrophic cardiomyopathy with contrast-enhanced MR imaging.

OBJECTIVE: Contrast-enhanced MR imaging has great clinical value as a means of characterizing myocardial tissue in patients with ischemic heart disease. The purpose of our study was to evaluate use of this technique in the assessment of patients with hypertrophic cardiomyopathy. CONCLUSION: On late-enhancement MR imaging, the various types or patterns of enhancement found in patients with hypertrophic cardiomyopathy are related to differences in morphology and regional function. Enhancement in hypertrophied areas likely reflects the presence of abundant connective tissue, foci of myocardial necrosis, or a combination of both.

Adolescent↗
PubMed2002

Embolization of large aneurysms with long wire coils.

The authors report the experience of using long coils of 2 m length in the management of large aneurysms. Knowledge of the characteristics of these coils is of value for correct placement. These coils are safe and cost-effective for excluding large aneurysms.

Aged↗
PubMed2002

Evaluation of abdominal aortic aneurysm after endoluminal treatment: comparison of color Doppler sonography with biphasic helical CT.

OBJECTIVE: The purpose of this study is to compare color Doppler sonography with biphasic helical CT in the evaluation of abdominal aortic aneurysms after endovascular repair. MATERIALS AND METHODS: Fifty-five patients prospectively underwent both color Doppler sonography and helical CT within 7 days after treatment by endovascular stent-graft. Aneurysmal thrombosis, the patency of the grafts, and the presence of a leak were evaluated in all patients. When a perigraft leak was observed, an attempt was made to identify its origin and outflow vessels. Helical CT was considered the gold standard technique. RESULTS: Helical CT revealed aneurysmal thrombosis in 33 patients and a perigraft leak in 22 patients. In five patients, helical CT detected a small perigraft leak not shown by color Doppler sonography. In three patients with suboptimal examinations, color Doppler sonography revealed a suspected perigraft leak that was not confirmed by helical CT. In these eight patients, the perigraft leak was sealed or no longer observed during follow-up. Compared with enhanced helical CT, the sensitivity and specificity of color Doppler sonography for the diagnosis of a perigraft leak were 77% and 90%, respectively. In seven other patients, helical CT was superior to color Doppler sonography in detecting the origin of the perigraft leak and the outflow vessels. Two iliac artery dissections and one distal migration of the prosthesis were revealed only by helical CT. CONCLUSION: Although color Doppler sonography may detect substantial perigraft leaks, helical CT is superior for detecting the origin of the perigraft leak, the outflow vessels, and the detection of complications related to the procedure.

Aged↗
PubMed2002

Expression of members of the calcium-binding S-100 protein family in a rat model of cerebral basilar artery vasospasm.

OBJECT: The aim of this study was to investigate the role of S-100 proteins in the onset of vasospasm induced by subarachnoid hemorrhage (SAH), which leads to severe neurological morbidity and death. It has recently been argued that modifications in the levels of expression of some intracellular signaling elements controlling the organization of the actin cytoskeleton (including the rho A small guanosine triphosphatase and its related kinases) play significant roles in the induction of smooth-muscle cell contraction, a calcium-dependent process that is pathognomonic of SAH-induced vasospasm at the molecular level. Several members of the calcium-binding S-100 protein family are known to exercise significant control over the organization of the actin cytoskeleton. METHODS: The levels of expression of S-100 proteins in SAH-induced vasospasm have never been investigated. The authors therefore used a double-hemorrhage rat model of SAH-induced vasospasm to determine whether the levels of expression of S-100B, S-100A1, S-100A2, S-100A4, and S-100A6 proteins on immunohistochemical studies were significantly modified in this pathological condition. Quantitative determination of immunohistochemically confirmed expression of S-100 proteins (accomplished with the aid of computer-assisted microscopy) revealed that SAH-induced vasospasm is accompanied by a very significant increase in S-100B, S-100A2, and, to a lesser extent, in S-100A4 and S-100A6 expression, whereas this condition is not accompanied by significant modifications to S-100A1 expression. CONCLUSIONS: Such significant modifications in the levels of expression of different members of the S-100 protein family in SAH-induced vasospasm could relate to the various roles played by this specific class of calcium-binding proteins at the level of actin cytoskeleton organization. These modifications in S-100 protein expression seem relatively specific to SAH-induced vasospasm, because heparin-induced epilepsy-like symptoms were accompanied by dramatically distinct profiles of S-100 protein expression.

Animals↗
PubMedDate not supplied

Projection-based bolus detection for computed tomographic angiography.

Computed tomographic (CT) angiography is important for imaging studies on cardiovascular structures, peripheral vessels, and solid organs. In practice, a CT angiography scan is triggered by the bolus arrival at a prespecified anatomical location, which is determined using CT fluoroscopy. In this article, we propose a projection-based method adapted from the Grangeat formula to detect the bolus arrival. Then, we evaluate our new method in numerical and animal studies. Our results indicate that this method allows significantly better temporal resolution and is computationally more efficient, as compared with the image-based methods.

Algorithms↗