Cardiac MRI in Ischemic Heart Disease

Abstract

he first ECG-gated magnetic resonance (MR) images of the heart were acquired more than 25 years ago, and MR imaging (MRI) was initially used to evaluate the morphology and motion of the heart. With developments of late gadolinium-enhanced (LGE) MRI and myocardial perfusion MRI, the application of MRI in ischemic heart disease (IHD) has been considerably expanded in the past 10 years. Because MRI has high spatial resolution and excellent image contrast, subendocardial infarction and myocardial ischemia can be clearly visualized. In addition, MRI does not expose the patient to ionizing radiation nor require the administration of iodinated contrast medium, which is potentially nephrotoxic. Coronary MR angiography (MRA) is rapidly evolving and has emerged as a possible alternative to multidetector-row computed tomography (MDCT) for noninvasive visualization of coronary artery disease (CAD). In this review, we describe recent advances of cardiac MRI and coronary MRA, and demonstrate the usefulness of MRI for the diagnosis and risk stratification in patients with IHD. Assessment of Cardiac FunctionBreath-hold cine MRI with steady-state free precession (SSFP) sequence and segmented k-space acquisition has become the standard method of evaluating the morphology and function of the heart. Right ventricular (RV) function, as well as left ventricular (LV) function and mass, can be accurately determined with cine MRI. 1,2 Compared with cardiac MDCT, excellent delineation of blood and myocardium can be obtained on SSFP cine MRI without contrast administration. 3,4 With the use of cardiac multichannel receiver coils and parallel imaging techniques, such as sensitivity encoding (SENSE), the imaging time of SSFP cine MRI has been considerably shortened. Compared with echocardiography, MRI is not influenced by lung air, allowing the acquisition of high-quality cine MRI of the entire heart in any desired double oblique imaging planes, even in patients with pulmonary emphysema. Cine MRI is less operator-dependent and shows high inter-study reproducibility in the assessment of ventricular volumes and mass. This allows a considerable reduction in the patient numbers required to prove a hypothesis in research studies, offering a potential saving in costs. 5 High-dose dobutamine stress echo (≈40 μg · kg -1 · min -1 ) has become a well-established method for the diagnosis of myocardial ischemia. However, dobutamine stress echo has several disadvantages, including operator dependency and poor endocardial delineation in the basal lateral and inferior segments in a certain percentage of patients. Cine MRI allows noninvasive assessment of altered regional wall motion during dobutamine stress in all segments of the LV, with high spatial and temporal resolution. The respective sensitivity and specificity of high-dose dobutamine stress cine MRI were 83% and 83% by Hundley et al, 6 86% and 86% by Nagel et al, 7 89% and 75% by Jahnke et al, 8 and 78% and 88% by Paetsch et al 9 for the detection of significant CAD. A recent meta-analysis of dobu...

Multimodality Assessment of Cardiac Involvement in Churg-Strauss Syndrome Patients in Clinical Remission

“…The LGE phenomenon likely reflects irreversible myocardial injury caused by the substitution of viable heart tissue by either necrosis or fibrosis. 26, 27 The patients with a higher number of segments affected by LGE also more often demonstrated a decreased LVEF (≤50%), positive ECG stress test and ventricular arrhythmias on Holter monitoring as compared with the rest of the CSS group; findings already observed in other cardiomyopathies. 28-30 These results also indicate that LGE changes (and their location ie, infra) detected in CSS patients in remission carry important clinical consequences.…”

Left Ventricular Pseudo-False Aneurysm Detected With ECG-Gated Multidetector Computed Tomography and Cardiac Magnetic Resonance Imaging

“…5 Additionally, it is known that an imaging approach combining the LGE-mode and T2-weighted CMR can differentiate acute from chronic myocardial infarction, because T2-weighted CMR depicts infarct-related myocardial edema. 5 In conclusion, the combination of cardiac MDCT and CMR imaging is valuable for diagnosing pseudo-false aneurysm complicating acute myocardial infarction.…”

Evaluation of Cardiac Allograft Vasculopathy by Multidetector Computed Tomography and Whole-Heart Magnetic Resonance Coronary Angiography

“…12 The whole-heart, 3-dimensional (D), steady-state free precession (SSFP) technique, different from earlier methods of MRCA, is currently widely used, and has been well-validated for assessing patients with CAD. 13 The technique provides superior signal-to-noise and contrast-to-noise ratios, decreases dependence on the inflow of unsaturated protons, and facilitates multiplanar reconstructions. However, the feasibility of this whole-heart technique for detecting CAV has not been reported.…”