الفهرس 
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Abstract
Survivors of previous myocardial infarction (MI) face an increased risk of new cardiovascular events, there is great focus on detecting and accurately assessing the infarcted region. Important aspects of this assessment include determining the infarct’s location, size, and transmural extent. Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) has been considered the reference standard in the non-invasive assessment of myocardial viability for almost two decades now. Its ability to clearly depict areas of myocardial infarction from viable myocardium is well established, making LGE a widely accepted component of standard clinical CMR protocols.
This was an observational study conducted at the diagnostic and interventional radiology department, Faculty of Medicine, Beni-Suef University Hospital to evaluate the role of magnetic resonance imaging pattern of myocardial enhancement in diagnosis of ischemic cardiomyopathy.
The study was conducted on 30 patients with clinical and echocardiographic evidence of ischemic cardiomyopathy, examined by cardiac MRI for the assessment of cardiac ventricular function and tissue characterization. The study images included static Cine CMR images and Late gadolinium enhancement (LGE) after intravenous infusion of gadolinium chelate contrast material (0.1-0.2 mmol\kg) followed 10-30 minutes later by a cardiac –gated T1 weighted pulse sequence using a segmented inversion recovery prepared fast gradient echo sequence.
The main findings of the current study are:
The mean age of patients was 55.2 + 11.9 years and most of them were males 23 (76.7%).
As regards the risk factors for ischemic heart diseases, our study observed that, 13 patients were smokers (43.3%), 17 were hypertensive (56.7%), 15 had
diabetes (50%), 12 had dyslipidemia (40%) and 19 had previous history of myocardial infarction (63%). There was a significant association of higher median number of segments of SE (LGE<50%) with female sex, higher median number of segments TM (LGE>50%) and male sex. Unexpectedly, non-hypertensive patients had significantly higher median number of segments with TM (LGE>50%). In addition, patients without history of previous ischemia had higher number of segments with SE (LGE<50%).
The median scar size was 12 ml and the median percentage was 13.5%. There was a significant negative correlation between the scar size and percentage and the number of segments with no LGE, while the number of segments with TM (LGE>50%) had a strong positive correlation.
The distribution of segments as detected by CMR with LGE in our study showed that, out of the total 510 segments, 230 segments showed LGE (scarred myocardial segments) while the remaining 280 segments did not show any enhancement (non-scared myocardial segments). Among the detected diseased segments, transmural segments were 135 (54.9%) and subendocardial segments were 95 (18.6%). The mean number of segments detected in each case with LGE was 4.5±3.1 for transmural segments and 3.2±2.9 for subendocardial segments. The most affected segment with subendocardial enhancement (SE) was segment 7
(Mid-anterior) and the most affected segment with transmural enhancement (TM) was segment 17 (Apex).
Analysis of myocardial wall motion by CMR with LGE in our study with examination of CINE images, out of the total 510 segments, 143 segments showed normokinesia with a median number (5), 213 segments showed hypokinesia with a median number (6), 147 segments showed akinesia with a median number (5) and
7 segments showed dyskinesia with a median number (0). The most affected segment with hypokinesia was segment 1 (basal-anterior), the most affected segment with akinesia was segment 14 (Apical-septal) and the most affected segment with dyskinesia was segment 17 (Apex). Our study also found that out of the 95 segments showing subendocardial enhancement SE (LGE<50%), 49 (51.6%) segments showed hypokinesia, 11 (11.6%) segments showed normal wall motion, 35 (36.8%) showed akinesia and none of the segments showed dyskinesia. Out of the 135 segments showing transmural enhancement TM (LGE>50%), 33 (24.4%) segments showed hypokinesia, 94 (69.6%) segments showed akinesia, and 7 (5.2%) segments showed dyskinesia. Hence, as the degree of LGE increases, the severity of wall motion abnormality also increases. There was a significant association between the non LGE and normokinesia and hypokinesia while the transmural LGE >50% was significantly associated with akinesia and dyskinesia.
The left anterior descending artery (LAD) was found to be the most commonly affected coronary artery, showing myocardial scar along its perfusion territory in 26 patients (86.7%), followed by the right coronary artery (RCA) in 9 (30%) patients then the left circumflex (LCX) in 8 (26.7%) patients.
There was an agreement between echocardiography and CMR for the estimation of left ventricular ejection fraction (LVEF). The mean EF by CMR was
(29.4±7.7) and the mean EF by echocardiography was (30.9±6.6) which means that the two tests are more or less equivalent.
CMR was able to measure all cardiac volumes and functions and values were as follows: the median LVEF (32), LVEDV (235.5), LVESV (163.5), LVEDVI (131.5), LVESVI (85.5), LV SV (73.5), RVEF (51.5), RVEDV (149), RVESV
(70.5), RVEDVI (78.5), RVESVI (35.5), RVSV (66.5) and CO (5.25).
There were insignificant differences between cases with SE lesions only, TM lesions only and TM+SE lesions regarding the LVEF, LVEDV, LVESV, LV SV (P- value>0.05). There was a moderate positive correlation between LVESV, LVEDVI and LVESVI and number of segments with TM enhancement (LGE>50%), while there is significant negative correlation between the LVEDV and LVESV and the number of segments with no LGE. It also showed that there was a moderate positive correlation between LVEDV and LVESV and added number of segments with SE to TM.
As regards microvascular occlusion and LV thrombus detection in our study, there was only one case with MVO while the LT ventricular thrombus was present in 8 cases (26.7%). There was an insignificant association between the LV thrombus and the number of segments with no LGE, number of segments with SE (LGE<50%) and the number of segments with TM (LGE>50%). In spite of being statistically insignificant, there was increased number of segments with TM (LGE>50%) in cases with LV thrombus, which it is still clinically significant.