الفهرس 
Radiological Anatomy of Coronory ArteriesOnly 14 pages are availabe for public view
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Abstract
Coronary CT imaging of coronary artery stents evolved as a reliable tool in the diagnostic workup of patients after coronary revascularization therapy. With 64 slice or newer generation, CT scanners cardiac CT is well suited to rule out Instent restenosis and stent occlusion in the presence of coronary stents with a diameter equal to or exceeding 3 mm. In these patients, cardiac CT has to be considered in clinical pathways as an alternative to invasive coronary angiography for the workup of patients with suspected Instent restenosis or stent complications after revascularization.
The development and evaluation of comprehensive examination protocols assessing morphology and hemodynamic significance of potential stent complications will further enhance the diagnostic potential of cardiac CT after coronary stenting.
The objective of the study was to evaluate patency of coronary artery stents by the 128 slice multi slice CT and to show the correlation between complicated stents and major coronary artery risk factors.
40 patients with known history of CAD and stent implantation were scheduled for elective multislice CT coronary angiography between December 2012 and June 2013, They were referred to the CT unit in Cairo radiology center (Cairo scan) for CT coronary angiography for stent evaluation and follow up of CAD.
58 stents were examined 2 stents were excluded from data and considered as non evaluable because of strong artifact and thick stent strut with difficulty in assessing the lumen patency.
from 56 stents 6 stents were complicated,2 stents with instent restenosis and 4 occluded stents, the stents were visualized using the standard filter implemented in the scanner and viewing angles obtained in curved multiplanner reformats,the protocol is used for Definition dual source (Siemens Medical Solutions, Forchheim, Germany) with 300 ms gantry rotation time and 128 multi-detector slices dual source of energy.Calicium score is not done.
The contrast-enhanced ECG gated scan was obtained within one single breath-hold (average 10s, 64 x 0.6 mm, tube current up to 430 mA at 120 kV).
All complicated stents were in patients having diabetes, diabetic patients have high incidence of neointimal hyperplasia and revascularization failure,in our patients the poor control of diabetes play a major role in this high incidence rates and because we have limited number of population and our study was in one center in Cairo (Egypt) so we could not generalize the results.
In our study we found that diabetic patients show highly significant difference to those non diabetics with regard to stent complications,40% of diabetics (n=6) out of 15 diabetics show complicated stents and there’s 0% non diabetics has stents with (p value 0.001),and this means that all non diabetics in our study populations have no stent complication.
The type of stents used were drug eluting stents in all patients of diabetes and other patients were having metallic stents,the stent lumen is seen in different angles and post stent run off of contrast is seen clearly in patent stents, any hypodensity in the stent lumen is considered neointimal hyperplasia and measurement of the hypodense area in relation to cross sectional area of the lumen to consider the instent restenosis and if the lumen is blocked by the thrombus so an occlusion is considered. In our study we didn’t measure the accuracy of 128 slice MDCT but we depend on it as a non invasive tool taking into consideration the previous studies about accuracy, in comparison to previous studies we found very close figures with regard to evaluating stent numbers and exluding instent restenosis.
We found that there’s a significant difference between females and males with regard to stent patency we found that 5 females 33.3% have complicated stents while 1 male 4% has complicated stent, this shows different results in previously published reports by (Zhang et al., 2010) which shows that no significant difference for ages after 55 years.
Smoking, hypertension, hyperlipidemia, and positive family history shows no significant statistical correlation with regard to stent patency.
In our study we found that the site of stent in the coronary artery is showing significant stastical difference being in LAD 33.3% LCX 33.3% and RCA 0% with p=0.48.
In our study we found there’s higher incidence of stent complications in single stent than double stents with 27.3% n=6 for single versus 0% n=18 for double stents with p=0.024.
In our study we found that theres high statistically significant difference with regard to age the mean age of patients with patent stents (52.3 ± 7.2 SD) while the mean age of patients with complicated stents was (60.5± 6.7 SD) with p value =0.01.