Читать книгу Interventional Cardiology - Группа авторов - Страница 271

CMR is useful for the initial evaluation of cardiac structure and function for known or suspected heart failure (HF), patients who are undergoing or are scheduled to begin chemotherapy, patients with familial or genetic dilated cardiomyopathies, suspected pulmonary hypertension, and to determine candidacy for implantation of permanent pacemakers and/or defibrillators [54].

It offers a more accurate assessment of function and morphology than most other imaging modalities. Cine sequences are used to visualize and quantify global atrial and ventricular systolic function relative to reference datasets. The pattern of scarring on late gadolinium enhancement (LGE) allows for accurate discrimination of ischemic from non‐ischemic cardiomyopathies [55]. Ischemic scar is subendocardial or transmural. Non‐ischemic cardiomyopathies either do not have detectable scars or have a non‐subendocardial distribution. In hypertrophic cardiomyopathy (HCM), LGE is patchy and intramyocardial, typically in the hypertrophied regions and in the interventricular septum close to the right ventricular (RV) insertion areas [56, 57] (Figure 10.4a–f). In dilated cardiomyopathy, a mid‐myocardial stripe of septal fibrosis is typical and is of strong prognostic value [58]. T2‐weighted CMR may be useful to detect myocardial inflammation due to acute myocarditis [59, 60]. Quantification of T2* relaxation times have proven useful for estimating intramyocardial iron content [61]. Non‐compaction cardiomyopathy is characterized by a thin compacted myocardium in the mid and apical segments of the LV. An end‐diastolic ratio of the non‐compacted to compacted LV myocardium of ≥2.3 is considered diagnostic [62]. ARVC is characterized by global or regional dilatation of the RV (and in some cases the LV) [63]. Cardiac amyloidosis has the classic appearance of a low signal “dark” blood pool and a very high signal intensity in the myocardium that is difficult to “null” on LGE images [64].

Figure 10.1 (a) Severe stenosis in the proximal RCA on CTA with high‐risk CT features such as positive remodeling and atherosclerotic plaque with low attenuation, (b) Stent in the proximal LAD without in‐stent restenosis. The lumen is well‐visualized, (c) Patent LIMA graft to the distal LAD, (d) Patent LIMA graft to LAD with a stent in the proximal LAD. Lumen of the LAD stent is difficult to visualize due to partial voluming artifact.

Figure 10.2 (a) Post‐TAVR, a bioprosthetic valve is seen in aortic position, (b) TAVR leaflets appear thickened, (c) Right coronary leaflet has restricted motion.