Paramagnetic contrast enhancement of coronary atherosclerotic lesions in ECG-gated study of the heart by using open MRI-scanners

The aim of the study was to evaluate the capabilities of contrast-enhanced magnetic resonance imaging (MRI) with the use of open MRI scanners for detection of atherosclerotic plaques in patients with extensive atherosclerosis and myocardial infarction which occurred two to six months prior the examination. Twenty four patients with angiologically verified coronary atherosclerosis comprised the patient’s group including 11 patients with predominant involvement of right coronary artery (RCA) and 13 patients with predominant atherosclerosis of left circumflex coronary artery. All patients received contrast-enhanced MRI study of the heart by using T1-weighted spin-echo with end-diastolic ECG gating (MRI scanners AZ-360 with 0.38T field and Magnetom Open with 0.22T) Thin 7-8-mm axial slices of the whole heart were obtained in four-chamber position in all patients; short axis slices were obtained in 16 out of 24 patients. Acquisition parameters were as follows: repetition time (TR) of 450-890 ms; echo time (ET) of 15-25 ms; 256х256 matrix; slice thickness of 7-8 mm; cross-dimension field of view of 25х25 cm; and voxel size of 0.1 to 0.12 mm. Paramagnetic (Optimark, Mallinckrodt Inc.) was injected as 2 mL of 0.5-M solution per 10 kg of body weight. For the atherosclerotic plaque itself and arterial wall beyond the plaque, the index of image enhancement (IE) was calculated as follows: IE = intensity of T1 w SE scan with paramagnetic / Intensity of T1 w sE scan initial. When analyzed visually, the T1-weighted contrast-enhanced MRI images in patients with coronary atherosclerosis provided clear delineation of coronary artery stenosis due to the significant uptake of paramagnetic by the plaque itself. In patients from the control group free of atherosclerosis, the RCA IE and LCA IE were 1.08+0.06 and 1.09±0.07, respectively. The atherosclerotic plaque in infarction-related LCA demonstrated IE as high as 1.52+0.23, whereas the plaque in infarction-related RCA was enhanced with IE=1.43±0.17. Also, the plaque-free areas of infarction-related arteries demonstrated mild but elevated enhancement with IE=1.18+0.10. In this small group, no significant correlations were revealed between IE and degree of stenosis or LV contractility indices. The authors conclude that contrast-enhanced MRI of coronary atherosclerotic plaques is recommended as an addition to inversion recovery protocol that provides effective imaging of paramagnetic uptake by damaged myocardium.

магнитно-резонансная томография сердца, атеросклероз, парамагнитное контрастирование, коронарная бляшка, magnetic resonance imaging, paramagnetic contrast enhancement, atherosclerosis, coronary plaque

1. Бобрикова Е.Э., Щербань Н.В., Ханеев В.Б. и др. Оценка состояния атеросклеротических бляшек брахиоцефальных артерий средствами высокоразрешающей контрастированной МРТ: взаимосвязь с ишемическим повреждением головного мозга // Мед. визуализация. - 2013. - № 1. - С. 26-34.

2. Гарганеева А.А., Округин С.А., Зяблов Ю.И. Программа ВОЗ “Регистр острого инфаркта миокарда”: 25-летнее эпидемиологическое изучение инфаркта миокарда в среднеурбанизированном городе Западной Сибири // Сибирский медицинский журнал (Томск) - 2012. - Т. 25, № 2. - C. 44-48.

3. Усов В.Ю., Шелковникова Т.А., Лукъяненок П.И. и др. ЭКГ-синхронизированная контрастированная МРТ миокарда на открытом МР-томографе в оценке ишемического повреждения миокарда у пациентов перед аортокоронарным шунтированием // Мед. визуализация. - 2011. - № 5. - С. 114-122.

4. Carlier S., Kakadiaris I.A., Dib N. et al. Vasa vasorum imaging: a new window to the clinical detection of vulnerable atherosclerotic plaques // Cur. Atheroscler. Rep. - 2005. -Vol. 7, No. 2. - P. 164-169.

5. Edelman R.R. Contrast-enhanced MR imaging of the heart // Radiology. - 2004. - Vol. 232, No. 3. - P. 653-668.

6. Harrison A., Adluru G., Damal K. et al. Rapid ungated myocardial perfusion cardiovascular magnetic resonance: preliminary diagnostic accuracy // J. Cardiovasc. Magn. Reson. - 2013. -Vol. 27, No. 15(1). - P. 26-30.

7. Kerwin W.S., Liu F., Yarnykh V. Signal features of the atherosclerotic plaque at 3,0 Tesla versus 1,5 Tesla: impact on automatic classification // J. Magn. Reson. Imaging. - 2008. -Vol. 28, No. 4. - P. 987-995.

8. Li F., McDermott M.M., Li D. et al. The association of lesion eccentricity with plaque morphology and components in the superficial femoral artery: a high-spatial-resolution multicontrast weighted CMR study // J. Cardiovasc. Magn. Reson. -2010. - No. 7. - P. 12-37.

9. Li T., Zhao X., Liu X. et al. Evaluation of the early enhancement of coronary atherosclerotic plaque by contrast-enhanced MR angiography // Eur. J. Radiol. - 2011. - Vol. 80, No. 1. - P. 136-142.

10. Maintz D., Ozgun M., Hoffmeier A. et al. Selective coronary artery plaque visualization and differentiation by contrast-enhanced inversion prepared MRI // Eur. Heart J. - 2006, Jul. - Vol. 27, No. 14. - P. 1732-1736.

11. Millon A., Mathevet J.L., Boussel L. et al. High-resolution magnetic resonance imaging of carotid atherosclerosis identifies vulnerable carotid plaques // J. Vasc. Surg. - 2013. - Vol. 57, No. 4. - P. 1046-1051.

12. Uemura S. Invasive imaging of vulnerable atherosclerotic plaques in coronary artery disease // Circ. J. - 2013. - Vol. 77. -P. 869-875.

13. Worthley S.G., Helft G., Fuster V. et al. Noninvasive in vivo magnetic resonance imaging of experimental coronary artery lesions in a porcine model // Circulation. - 2000. - Vol. 101. - P. 2956-2961.