الفهرس 
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Abstract
Cardiac magnetic resonance (CMR) imaging is a non-invasive technique that is considered the reference standard for the measurement of global ventricular quantitative parameters, as well as for regional qualitative wall motion assessment, because of its high accuracy. Accurate assessment of left ventricular ejection fraction (EF) is essential for prognosis and evaluating therapeutic responses in patients with ischemic cardiomyopathy.
The aim of this study was to emphasize the role of CMR in the evaluation of patients with ischemic cardiomyopathy to assess myocardial viability and accurate assessment of LV function at both regional and global levels.
During a 40 months period, from February 2016 till June 2019, we conducted a prospective study comprising 56 patients with two groups, “group A” represent 28 patients who are known to be chronic ischemic cardiomyopathy, while “group B” fulfilled the remaining 28 patients who presented with acute atypical chest pain as first presentation.
There were 42 (75%) males and 14 (25%) females with mean age of group Awas 59.1 ± 7.5 while the mean age of group B was 53.5 ± 11.8, ranging from 40 to 70 years.
All the patients in this study had one or more risk factors in both groups (A and B) such as diabetes mellitus (78.6% and 57.1%), arterial hypertension (57.1% and 57.1%), smoking (60.7% and 57.1%) and obesity with BMI ≥ 25 (82% and 75%).
According to the echocardiogram data in both groups (A and B), the mean LVESD was (4.3 cm and 3.6 cm) while the mean LVEDD was (5.4 cm and 4.7 cm). The mean EF was (32.3% and 40.1%). The wall motion (WM) abnormality was (100% and 75%). The sum of wall motion (WM) abnormality segments was calculated in both groups (A and B). Hypokinetic segments were presented in (36.8% and 65.1%) while the akinetic segments were presented in (53.8% and 18.1%).
Regarding the CMR data in both groups (A and B), the mean LVESD was (4.4 cm and 3.7 cm) while the mean LVEDD was (5.6 cm and 4.8 cm). The mean EF was (30.4% and 39.1%). The mean LVESV was (170.6 mL and 97.5mL) while the mean LVEDV was (237.1 mL and 154.3mL). The WM abnormality was (96.4% and 100%).
The sum of WM abnormality segments was calculated in both groups (A and B). Hypokinetic segments were presented in (40% and 65.9%) while the akinetic segments were presented in (47.3% and 25.3%).
The myocardial segment viability of the patients in group A that estimated via LGE technique revealed that the patients with LGE < 50% who were eligible for revascularization procedures represented about 39.3%. While, patients with LGE > 50% who were not eligible for revascularization procedures and not having any viable segment represented 60.7%. It was found that (LAD) was the most diseased in this group 78.6% followed by (RCA) was 50%, and (LCX) was 39.3%. The mean infarct size core was 22.96 in this group and 16 patients have post MI complications (57.1%).
Regarding the pattern of late gadolinium enhancement (LGE) in group B, it was revealed that patients with ischemic CMR criteria represented about 54%. According to the myocardial segment viability of the patients in this group that estimated via LGE technique revealed that the patients with LGE < 50 represented about 60%. While, patients with LGE > 50% represented 40%. It was found that (LAD) was the most diseased in this group 53.3% followed by (RCA) was 33.3%, and (LCX) was 26.6%. The mean infarct size core was 22.96 in this group and the patients who have post MI complications were 32.1% and those who have MVO were 28.6%. The estimated SIR of the ischemic patients revealed that patients who had good SIR were 66.7%.
It was found that the EFs detected by echocardiography were overestimated relative to MRI with statistically significant difference (p=0.004). LV diameters detected by echocardiography were underestimated relative to MRI with statistically significant difference with (p=0.003). CMR was much more sensitive than Echo to detection of segmental wall motion abnormalities (p < 0.001).
The Bland Altman Plot for measuring the agreement between Echocardiography and MRI for estimation of ejection fraction (EF) was noted. Among 56 patients, the mean EF by MRI was 34.8% and the mean EF by echocardiography was 36.2% with a mean difference of 4.6%. SD of bias was of 3.67 and 95% limits of agreement were 9.94: –7.83
In our study, there was positive very high correlation between the two modalities (CMR and 2D Echo) in evaluation of LV Functionality indices (WMA Segment Number, LVESD, LVEDD and LVEF) with Pearson’s Correlation Coefficient (0.824, 0.914, 0.969 and 0.952 respectively) andstatistically significant difference in all parameters (p < 0.001).
There is good agreement between cardiac magnetic resonance and echocardiography regarding segmental wall motion with Cohen’s Kappa is (0.76), P value of (0.011). Per-segment agreement between echocardiography and MRI as regards the detection of segmental wall motion abnormality in the 476 segments in our study, it was found that there was high agreement between the two modalities in evaluation of the SWMA as both cardiac MRI and 2D Echo detected 1.8% with no motion abnormality, hypokinesia in 28.6% of patients and Akinesia in 3.6% of total patients.
This study results reported that there was an agreement between the two modalities (CMR and conventional coronary angiography) with very high kappa agreement (0.814) and statistically significant Chi-square (p=0.001). Both modalities detected (LAD) affected territory only in 26% of the 28 patients while (LAD & LCX) diseased territories seen in 11% and (LAD & RCA) diseased territories seen in 18.5%.
MRI was of value in diagnosis of post MI complications & other cardiac abnormalities using echocardiography as the reference standard. MRI showed a NPV of 89.4% for the evaluation of the left ventricle (LV) enlargement, for left atrial (LA) enlargement of NPV was 85.7%, LV cavitary thrombus was 97.6% and as for valvular lesions, NPV was 95.2%.
Conclusion