[CT and MR Imaging Findings of Structural Heart Diseases Associated with Sudden Cardiac Death]

Abstract

Sudden cardiac death is an unexpected death originating from the heart that occurs within an hour of the onset of symptoms. The main cause of sudden cardiac death is arrhythmia; however, diagnosing underlying structural heart disease significantly contributes to predicting the long-term risk. Cardiovascular CT and MR provide important information for diagnosing and evaluating structural heart disease, enabling the prediction and preparation of the risk of sudden cardiac death. Therefore, we would like to focus on the various structural heart diseases that increase the risk of clinically-important sudden cardiac death and the importance of imaging findings.

Fig. 1. Cases of vulnerable plaque.

A. Curved MPR CCTA image shows significant stenosis with a noncalcified plaque (arrow) with central low attenuation (inlet, arrowhead) and positive remodeling in proximal right coronary artery. B. Curved MPR CCTA image shows significant stenosis with mixed calcified and noncalcified plaque (arrow) with peripheral contrast rim or napkin ring sign (inlet, arrowhead) and positive remodeling in proximal left anterior descending coronary artery. CCTA = coronary CT angiography, MPR = multiplanar reformat

Fig. 2. A 55-year-old male who had an acute myocardial infarction and underwent percutaneous coronary intervention.

A, B. Delayed contrast-enhanced cardiac MR images show transmural delayed enhancement (arrows) and perfusion defect (arrowheads), corresponding to the transmural extent of myocardial infarction and microvascular occlusion in the basal to mid inferior and inferolateral LV wall. Pericardial effusion is also noted. C, D. T1 and T2 mapping images show transmural high T1 and T2 values (arrows) and low T1 and T2 values (arrowheads) in the basal to mid inferior and inferolateral LV walls. LV = left ventricle

Fig. 3. A 81-year-old female with LV free wall rupture.

A. Non-contrast CT image shows acute hemopericardium (arrowheads). B–D. Contrast-enhanced axial (B), short-axis (C), and two-chamber (D) multiplanar reformat CT images show patchy contrast filled outpouching lesion (arrows) surrounded by a low signal intensity in mid anterior LV wall (arrowheads) E. Curved MRP coronary CT angiography image shows significant stenosis with a noncalcified plaque in the proximal left anterior descending coronary artery (arrows). LV = left ventricle

Fig. 4. A 79-year-old male with LV free wall rupture.

A. Non-contrast axial CT image shows acute hemopericardium (arrows). B. Contrast-enhanced axial CT image shows patchy contrast-filled outpouching lesion (arrow) in the lateral LV wall. C, D. Cardiac CT obtained 1 week later show no contrast leakage in the LV lateral wall on early phase three-chamber MPR image (C) and patchy hypoenhancement (arrow) in the basal lateral LV wall on a 5 min delayed phase three-chamber MPR image (D). E. Curved MPR coronary CT angiography image shows occlusion in the distal left circumflex artery (arrow). F, G. Delayed contrast-enhanced short axis (F) and three-chamber (G) cardiac MR images show transmural delayed enhancement (arrows) with central low signal intensity (arrowheads) in the basal to mid-lateral wall LV wall. LV = left ventricle, MPR = multiplanar reformat

Fig. 5. A 61-year-old male with anomalous origin of coronary artery arising from the opposite sinus of Valsalva.

A, B. Double oblique maximum intensity projection images of the aortic valve show the RCA (arrows) originating from the opposite sinus of Valsalva and passing between the aorta and the pulmonary trunk and show a dynamic slit-like luminal narrowing of the proximal RCA at mid-diastole (A) and end-systole (B). RCA = right coronary artery

Fig. 6. A 35-year-old male with anomalous origin of coronary artery arising from the opposite sinus of Valsalva and acute myocardial infarction.

A. A curved MPR CCTA image shows an RCA (arrow) arising from the left sinus of Valsalva with an interarterial course between the aortic root and the pulmonary trunk and luminal narrowing of the proximal RCA without atherosclerotic plaque. Insignificant stenosis with a noncalcified plaque is also noted in the proximal RCA (arrowhead). B, C. Two-phase short-axis MPR CT images show transmural early hypoattenuation and delayed hyperenhancement (arrows) in the mid inferoseptal and inferior left ventricle wall. D. Conventional coronary angiography shows the RCA (arrows) arising from the left sinus of Valsalva. CCTA = coronary CT angiography, MPR = multiplanar reformat, RCA = right coronary artery

Fig. 7. A 55-year-old male with hypertrophic cardiomyopathy.

A. Cardiac MR LVOT image shows asymmetrical septal hypertrophy (arrows) with a maximal thickness of 27 mm at diastole. B, C. Cardiac MR LVOT images show pencil-like mitral regurgitation flow back (arrowheads) into the left atrium at early systole (B) and near complete collapse of the LV cavity (arrow) and flow turbulence at the level of stenosis of the LVOT at mid-systole (C). In this case, the mitral regurgitant volume is the difference (7 mL) between the LV stroke volume (63 mL) and the aortic forward stroke volume (55 mL) measured by phase-contrast cardiac MR. The mitral regurgitation fraction is the ratio (0.11) of the mitral regurgitant volume (7 mL) divided by the LV stroke volume (63 mL). The peak velocity of the flow jet in the LVOT measured by phase-contrast cardiac MR was 1.6 m/sec. D. Cardiac MR short-axis image measures the cross-sectional area of the LVOT (1.5 cm²). E. Delayed contrast-enhanced short-axis cardiac MR image shows diffuse mid-wall delayed enhancement (arrows) in the mid anterior and anteroseptal LV wall. F. T1 mapping image shows high T1 values (arrows) in the mid-layer of the interventricular septum of the left mid-ventricle. LV = left ventricle, LVOT = left ventricular outflow tract

Fig. 8. A 62-year-old male with dilated cardiomyopathy.

A. Cardiac MR four-chamber image shows dilated LV and left atrium with decreased LV wall thickness except for mid septum and reveals pleural effusion and pericardial effusion. B. Delayed contrast-enhanced short-axis cardiac MR image shows diffuse mid-wall delayed enhancement (arrows) in mid septum, anterior and inferior LV wall. C. T1 mapping image shows high T1 values in the mid-wall of the entire middle LV (arrows). LV = left ventricle

Fig. 9. A 26-year-old male with acute myocarditis.

A. Cardiac MR short-axis T2 weighted image shows subepicardial high signal intensity (arrows) in the mid-lateral LV wall. B, C. Delayed contrast-enhanced short-axis (B) and four-chamber (C) cardiac MR images show a delayed enhancement in mid to apical lateral LV wall (long arrows), mid-wall patchy delayed enhancement in the mid septum (arrowhead), and subendocardium in the apical septum (short arrow). LV = left ventricle

Fig. 10. A 61-year-old male with cardiac amyloidosis.

A. Cardiac MR four-chamber image shows asymmetric LV septal hypertrophy, pleural effusion, and pericardial effusion. B, C. Delayed contrast-enhanced four-chamber (B) and short-axis (C) cardiac MR images show diffuse, circumferential subendocardial delayed enhancement (arrows) in all four cardiac chambers (B), particularly global transmural delayed enhancement in the LV wall (C, arrowheads). D. T1 mapping image shows high T1 values in the entire LV wall (arrowheads). LV = left ventricle

Fig. 11. A 74-year-old male with cardiac sarcoidosis.

A. Early contrast-enhanced four-chamber MPR CT image shows concentric LV wall hypertrophy. B. Delayed contrast-enhanced short-axis MPR CT image shows diffuse transmural and mesocardial delayed enhancement in mid-LV wall (arrows). C. Delayed contrast-enhanced short-axis cardiac MR image shows diffuse mesocardial enhancement in the septum and multifocal patchy mesocardial enhancement in mid anterior, lateral, and inferior LV wall (arrows). LV = left ventricle, MPR = multiplanar reformat

Fig. 12. A 57-year-old male with cardiac sarcoidosis.

A, B. Delayed contrast-enhanced four-chamber (A) and short-axis (B) cardiac MR images show subepicardial enhancement in the mid anterior, septal, and lateral LV wall (arrows) and mid-wall enhancement in the mid inferior LV wall (arrowheads). LV = left ventricle

Fig. 13. A 74-year-old female with severe aortic valve stenosis.

A. Non-contrast electrocardiogram-gated calcium scan shows severe calcification of the aortic valve. B. Double oblique MPR image of the aortic valve shows severely narrowed aortic valve orifice (area of 97 mm²) at systole. C. Short-axis MPR CT image shows hypertrophied mid-LV wall, particularly asymmetric septal hypertrophy (arrows) at end-diastole (septum: 19 mm and lateral wall: 10 mm in thickness). D. Delayed contrast-enhanced short-axis cardiac MR image shows diffuse mid-wall delayed enhancement (arrows) in the septum and subendocardial delayed enhancement in anterior wall and anterolateral LV wall. E. T1 mapping image shows high T1 values (arrows) in mid-wall in the septum and subendocardium in the anterior, lateral, and inferior LV wall. LV = left ventricle, MPR = multiplanar reformat

Fig. 14. A 76-year-old male with prosthetic valve thrombosis.

A. Double oblique multiplanar reformat image of the aortic valve shows thrombi (arrows) in the prosthetic aortic valve. B. Static cine image of the aortic valve shows severe slit-like narrowing of the opening of the prosthetic valve at systole (arrows).

Fig. 15. A 49-year-old male with suspected cardiac hemangioma.

A. Contrast-enhanced axial CT image shows a large tumor with low attenuation and scattered patchy and dot-like hyperenhancement in the left ventricle wall (arrowheads). B, C. Short-axis cardiac MR images show large hyperintense tumors on T2 weighted image (B, arrows), mixed early contrast filling (arrowheads), and perfusion defect (arrows) on first-pass perfusion image (C). D, E. Delayed contrast-enhanced short-axis (D) and axial (E) cardiac MR images show delayed enhancement with multiple dark signal intensity (arrows) suggestive of an intracavitary blood pool. F. Conventional coronary angiography shows blood supply and tumor blush (arrows) from the left anterior descending coronary artery and left circumflex artery.

Fig. 16. A 59-year-old male with left atrial myxoma.

A. Non-contrast electrocardiogram-gated CT image shows a low-attenuation mass (arrow) without fat or calcification in the left atrium. B. Contrast-enhanced axial CT image shows a pedunculated tumor attached to the interatrial septum (arrow). C. Left atrial myxoma with a stalk on a surgical specimen.

Fig. 17. A 82-year-old male with acute type A aortic dissection.

A. Initial chest radiograph shows mediastinal widening, enlargement of cardiopericardial silhouette, and left pleural effusion. B. Non-contrast CT image after the discontinuation of cardiopulmonary resuscitation shows dissection flap (arrowheads) with hyperattenuating false lumen involving ascending and descending thoracic aorta, pericardial hematoma (short arrows), and left pleural hematoma (long arrows). C, D. Contrast-enhanced electrocardiogram-gated thoracic aorta CT images show acute type A aortic dissection (short arrows) with hemopericardium and severe compression of the right pulmonary artery (arrowheads). Aortic hemorrhage extends to the right lung (long arrows) and left hemothorax with compressive atelectasis in the left lower lobe.

Fig. 18. A 61-year-old male with acute type A aortic dissection and myocardial infarction.

A, B. Four-chamber MPR CT images show Stanford type A aortic dissection with compressed right coronary artery ostium (arrow) due to an intimal flap (A). Coronary artery spasm is noted in the left main coronary artery without the involvement of the dissected flap (B, arrow). C, D. Short-axis MPR images of the LV show a subendocardial perfusion defect (arrows) in the mid anterior, anteroseptal, and anterolateral wall of the LV with severe hypokinesia at end-systole (D). E. Curved MPR coronary CT angiography image obtained 3 weeks after replacement of the ascending aorta showing no stenosis in the left main coronary artery (arrow) but insignificant stenosis in the left anterior descending coronary artery ostium (arrowhead). F. Short-axis MPR image of the LV shows no hypoenhancement in the previous hypoenhanced and hypokinetic LV wall. LV = left ventricle, MPR = multiplanar reformat

Fig. 19. A 61-year-old male with acute type A aortic dissection and severe aortic valve regurgitation.

A, B. Oblique coronal MPR CT images through the aortic root show Stanford Type A aortic dissection with a circumferentially dissected intimal flap (arrows), which is parallel to the aortic wall on systole and is prolapsed into the left ventricle through the aortic valve (arrowheads) during diastole (B), causing aortic regurgitation. C. Double oblique MPR image of the thoracic aorta at systole, shows the circumferential nature of dissection (arrows). MPR = multiplanar reformat