Focal Spot, Spring 2002

https://digitalcommons.wustl.edu/focal_spot_archives/1090/thumbnail.jp

Coronary Computed Tomography Angiography—A Promising Imaging Modality in Diagnosing Coronary Artery Disease

BackgroundTraditionally, information on coronary artery lesions is obtained from invasive coronary angiography (CAG). The clinical applicability and diagnostic performance of the newly developed 64-slice multislice computed tomography (MSCT) scanner in coronary angiographic evaluation is not well evaluated.MethodsCoronary computed tomography angiography (CCTA) was performed in 345 patients (119 women, 226 men; mean age, 59.64 ±11.67 years). Concomitant CAG was performed in 53 patients. The diagnostic performance of CCTA for detecting significant lesions was compared with that of CAG by 3 independent cardiologists.ResultsAll CCTA was performed without complication. Comparison between CCTA and CAG was made in the 53 patients who underwent both studies. Sensitivity, specificity and the positive and negative predictive values for the 53 patients were: 81%, 99%, 87% and 99%, respectively.ConclusionThe 64-slice MSCT, developed in recent years, allows reliable noninvasive evaluation of coronary artery morphology, including plaque, stenosis and congenital anomaly. The diagnostic accuracy of MSCT scans for detecting lesions makes it a good imaging substitute for CAG in the evaluation of these coronary segments. [J Chin Med Assoc 2008;71(5):241–246

Correlation of Agatston Score in Patients with Obstructive and Nonobstructive Coronary Artery Disease Following Stemi.

Coronary artery calcification (CAC) is noticed in the early atherosclerotic lesions that appear in the second and third decades of life, but it is more often found in the advanced atherosclerotic lesions and in older age. Coronary arterial calcification is a change occurring almost exclusively in atherosclerotic arteries, and is absent in the normal vessel wall. Hence the presence of any CAC is nearly 100% specific for atheromatous coronary plaque. Since both obstructive and nonobstructive lesions can have calcification present in the intima, CAC is not specific for obstructive coronary disease. The site and the amount of coronary artery calcium and the percent of coronary luminal narrowing at the same anatomic site, the relation is nonlinear and has large confidence limits. As the occurrence of calcification reflects an advanced stage of plaque development, some researchers have proposed that the correlation between coronary calcification and acute coronary events may be suboptimal based largely on angiographic series. In order to understand this apparent conflict between the stability of a calcified lesion and CHD event rates, one must recognize the association between atherosclerotic plaque extent and more frequent calcified and non-calcified plaque. That is, patients who have calcified plaque are also more likely to have non-calcified or "soft" plaque that is prone to rupture and acute coronary thrombosis. CONCLUSION : 1) Sixty four slice MDCT derived Agatston score is a useful tool to assess angiographic severity in Post MI population. 2) Agatston score shows poor correlation in differentiating the obstructive and nonobstructive coronary artery disease following STEMI. 3) Agatston scores showed good correlation in patients with obstructive CAD especially in Elderly, Diabetics and in those with a family history of CAD. 4) There is less correlation of Agatston score with regards to other conventional risk factors like Gender, Hypertension and Smoking in both obstructive and non obstructive CAD. 5) Agatston score was not useful to identity infarct related artery. 6) There was no linear correlation between Agatston score and the number of vessel involvement. 7) There was a significant negative correlation in hypertensive patients among non obstructive CAD population

Significance of coronary artery calcium scoring in patients with obstructive and non-obstructive coronary artery disease following stemi.

Coronary artery calcification (CAC) occurs in small amounts in the early lesions of atherosclerosis that appear in the second and third decades of life, but it is found more frequently in advanced lesions and in older age. C o r o n ary arterial calcification is part of the development of atherosclerosis, occurs almost exclusively in atherosclerotic arteries, and is absent in the normal vessel wall A positive CT study (defined as presence of any CAC) is nearly 100% specific for atheromatous coronary plaque. Since both obstructive and nonobstructive lesions can have calcification present in the intima, CAC is not specific for obstructive coronary disease. The site and the amount of coronary artery calcium and the percent of coronary luminal narrowing at the same anatomic site, the relation is nonlinear and has large confidence limits. As the occurrence of calcification reflects an advanced stage of plaque development, some researchers have proposed that the correlation between coronary calcification and acute coronary events may be suboptimal based largely on angiographic series5. In order to understand this apparent conflict between the stability of a calcified lesion and CHD event rates, one must recognize the association between atherosclerotic plaque extent and more frequent calcified and noncalcified plaque. That is, patients who have calcified plaque are also more likely to have non-calcified or "soft" plaque that is prone to rupture and acute coronary thrombosis. AIM OF THE STUDY: To compare CAC (coronary artery calcium) score in patients with Obstructive and Non obstructive CAD. To compare CAC score in patients with single and multivessel disease. To compare CAC score in males and females. To compare CAC score in those with and without HT, Smoking and Diabetes. To compare CAC score between IRA and other vessels in multivessel disease. CONCLUSION: 1) Sixty four slice MDCT derived CAC score is a useful tool to assess angiographic severity in Post MI population. 2) CAC scores showed good correlation in patients with obstructive CAD especially in Elderly, Diabetics and in those with a family history of CAD. 3) There is less correlation of CAC score with regards to other conventional risk factors like Gender, Hypertension and Smoking in both obstructive and non obstructive CAD. 4) CAC score was not useful to identity infarct related artery. 5) There was no linear correlation between CAC score and the number of vessel involvement. 6) There was a significant negative correlation in hypertensive patients among non obstructive CAD population

Cardiac Computed Tomography Methods and Systems Using Fast Exact / Quasi Exact Filtered Back Projection Algorithms

The present invention provides systems, methods, and devices for improved computed tomography. More specifically, the present invention includes methods for improved cone-beam computed tomography (CBCT) resolution using improved filtered back projection (FBP) algorithms, which can be used for cardiac tomography and across other tomographic modalities. Embodiments provide methods, systems, and devices for reconstructing an image from projection data provided by a computed tomography scanner using the algorithms disclosed herein to generate an image with improved temporal resolution

Application of Dual-Energy Computed Tomography to the Evalution of Coronary Atherosclerotic Plaque

Atherosclerotic coronary artery disease is responsible for around 50 of cardiovascular deaths in USA. Early detection and characterization of coronary artery atherosclerotic plaque could help prevent cardiac events. Computed tomography (CT) is an excellent modality for imaging calcifications and has higher spatial resolution than other common non-invasive modalities (e.g MRI), making it more suitable for coronary plaque detection. However, attenuation-based classification of non-calcified plaques as fibrous or lipid is difficult with conventional CT, which relies on a single x-ray energy. Dual-energy CT (DECT) may provide additional attenuation data for the identification and discrimination of plaque components. The purpose of this research was to evaluate the feasibility of DECT imaging for coronary plaque characterization and further, to explore the limits of CT for non-invasive plaque analysis. DECT techniques were applied to plaque classification using a clinical CT system. Saline perfused coronary arteries from autopsies were scanned at 80 and 140 kVp, prior to and during injection of iodinated contrast. Plaque attenuation was measured from CT images and matched to histology. Measurements were compared to assess differences among plaque types. Although calcified and non-calcified plaques could be identified and differentiated with DECT, further characterization of non-calcified plaques was not possible. The results also demonstrated that calcified plaque and iodine could be discriminated. The limits of x-ray based non-calcified plaque discrimination were assessed using microCT, a pre-clinical x-ray based high spatial resolution modality. Phantoms and tissues of different composition were scanned using different tube voltages (i.e., different energies) and resulting attenuation values were compared. Better vessel wall visualization and increase in tissue contrast resolution was observed with decrease in x-ray energy. Feasibility of calcium quantification from contrast-enhanced scans by creating virtual n

Application of Dual-Energy Computed Tomography to the Evalution of Coronary Atherosclerotic Plaque

Atherosclerotic coronary artery disease is responsible for around 50 of cardiovascular deaths in USA. Early detection and characterization of coronary artery atherosclerotic plaque could help prevent cardiac events. Computed tomography (CT) is an excellent modality for imaging calcifications and has higher spatial resolution than other common non-invasive modalities (e.g MRI), making it more suitable for coronary plaque detection. However, attenuation-based classification of non-calcified plaques as fibrous or lipid is difficult with conventional CT, which relies on a single x-ray energy. Dual-energy CT (DECT) may provide additional attenuation data for the identification and discrimination of plaque components. The purpose of this research was to evaluate the feasibility of DECT imaging for coronary plaque characterization and further, to explore the limits of CT for non-invasive plaque analysis. DECT techniques were applied to plaque classification using a clinical CT system. Saline perfused coronary arteries from autopsies were scanned at 80 and 140 kVp, prior to and during injection of iodinated contrast. Plaque attenuation was measured from CT images and matched to histology. Measurements were compared to assess differences among plaque types. Although calcified and non-calcified plaques could be identified and differentiated with DECT, further characterization of non-calcified plaques was not possible. The results also demonstrated that calcified plaque and iodine could be discriminated. The limits of x-ray based non-calcified plaque discrimination were assessed using microCT, a pre-clinical x-ray based high spatial resolution modality. Phantoms and tissues of different composition were scanned using different tube voltages (i.e., different energies) and resulting attenuation values were compared. Better vessel wall visualization and increase in tissue contrast resolution was observed with decrease in x-ray energy. Feasibility of calcium quantification from contrast-enhanced scans by creating virtual n