الفهرس 
Gross and CT anatomy of coronary arteriesOnly 14 pages are availabe for public view
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Abstract
Myocardial re-vascularization is one of the fundamental steps in the
clinical history of patients with coronary atherosclerotic disease.
Solving the symptoms of angina, improving tolerance to effort, and a
global gain in terms of reduced morbidity and mortality are the general
goals that coronary re-vascularization has tried to achieve since its
beginning.
Coronary stenting is the most widely used non-surgical coronary revascularization
procedure (537,000 interventional procedures in the USA
in 2002) and completes the dilatation performed during angioplasty.
Despite the use of newer and more sophisticated stents and drugeluting
stents, the risk of long term re-stenosis arising from in-stent
development of neointimal hyperplasia is high, varying between 4 and
40%. This high incidence justifies the use of diagnostic procedures to reevaluate
the stent in follow-up examinations. (P.Pavone, et al, 2009).
The surgical approach to coronary artery disease has evolved
significantly over the past several years.
The developments in this field have led to increased interest in the
use of newer imaging procedures, before and after graft placement.
(P.Pavone, et al, 2009)
In addition , Patients with multivessel disease generally don’t become
symptomatic until several bypasses are occluded. Nearly every third
patient has an asymptomatic bypass occlusion or stenosis 5 years after
CABG. ( Nikolaou K et al., 2006 )
Therefore; these patients need periodic assessment of the coronary
arterial tree through a reliable method with high sensitivity and
specificity. (Türkvatan A et al., 2009)
Conventional coronary angiography is considered the reference
standard for evaluation of coronary artery disease . however the risk of
potentially serious adverse effects and the cost associated with such
effects have led to search for noninvasive alternative. ( Sutton , 2003).
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This makes finding a noninvasive method for assessment of these
patient condition an urgent demand worldwide.
Multidetector Computed Tomography (MDCT) is now an established
modality for noninvasive cardiac imaging.
Advances in both the speed at which the X-ray source rotates and the
number of detectors have improved the ability of CT to resolve smaller
anatomic detail and have enabled imaging of the native coronary arterial
tree (P.Pavone, et al, 2009).
The 2 major recent advancements in multidetector CT technology
are dual-source 64-slice CT and single-source 256- and 320-slice CT.
Both of these techniques offer the possibility of reduced radiation dose
compared with single-source 64-slice CT. Dual-source CT allows
coronary CT angiography (CCTA) to be performed at higher heart rates.
Another advantage is that if the data can be acquired in one heartbeat,
phase misregistration artifacts arising from irregular heartbeats are not an
issue. (Eugene C Lin et al, 2009)
But , most of the literature reports refer only to the use of 64-row
detector CT and there are, as yet, essentially no data available for higherlevel
equipment (128, 256, 320 rows).(P.Pavone, et al, 2009)
In conclusion , the accuracy of CT angiography to detect obstructive
graft disease is almost 100%. Comprehensive post-bypass surgery
evaluation should also include the assessment of the native coronary
arteries, which may prove challenging as a result of advanced, diffuse
coronary artery disease. .(Pim J de Feyter et al, 2008)
In the presence of a chronic coronary atherosclerotic plaque,
coronary CTA is a viable diagnostic option to detect the presence of
coronary plaques (calcific and non-calcific) and to rule out significant
stenosis and can provide information about the composition (calcific
and non-calcific) of the plaque and then the success of a coronary
angioplasty. (P.Pavone, et al, 2009)
In addition , Multidetector CT is a useful mean for mapping the
course of a left IMA graft before repeat surgery ,thereby minimizing the
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risk of injury to the graft vessel during surgical reentry.(Frank J. R. et
al, 2008)
For stents , Current 16- and 64-slice CT technology allows reliable
assessment of large-diameter (≥3 mm) coronary artery stents. Metalrelated
artifacts preclude the correct evaluation of stents with smaller
diameters. In parallel with new technical developments in MSCT
technology, the preferable use of thin strut or low-density metal stents
will further improve overall stent imaging. .(Pim J de Feyter et al, 2008)