Section V Cardiac Radiology

Transcription

1 Section V Cardiac Radiology Figure Based on the diagram (Figure 1), which of the following vessels typically supplies the anterolateral cardiac segment? A. Left anterior descending B. Circumflex artery C. Right coronary artery D. Posterior descending artery You are shown a segmental diagram of the heart with anatomic labels. A: The left anterior descending artery supplies the anterior and anteroseptal cardiac segments. B: The circumflex artery supplies the anterolateral and inferolateral cardiac segments. C: The right coronary artery supplies the inferolateral and inferior cardiac segments. D: The posterior descending artery supplies the inferior cardiac segment.

2 Horizontal long axis MIP Figure What is the MOST LIKELY diagnosis (Figure 2)? A. Lipomatous hypertrophy of the interatrial septum B. Sinus venosus atrial septal defect C. Septum primum atrial septal defect D. Septum secundum atrial septal defect Horizontal long axis MIP from a contrast-enhanced cardiac CT scan shows a defect high in the interatrial septum consistent with a sinus venosus atrial septal defect. A: The image shows an abnormal connection between the superior aspect of the right atrium and the left atrium, consistent with sinus venosus atrial septal defect. A small amount of fat is present in the interatrial septum and can be a normal finding. When lipomatous hypertrophy of the interatrial septum is present, there is sparing of the fossa ovalis. However, the fossa ovalis is more centrally located in the interatrial septum. B: The image shows an abnormal connection between the superior aspect of the right atrium and the left atrium, consistent with sinus venosus atrial septal defect. C: The image shows an abnormal connection between the superior aspect of the right atrium and the left atrium, consistent with sinus venosus atrial septal defect. Septum primum defects are located close to the atrioventricular valve plane. D: The image shows an abnormal connection between the superior aspect of the right atrium and the left atrium, consistent with sinus venosus atrial septal defect. Septum secundum atrial septal defects are located at the foramen ovale.

3 Transverse FDG-PET CT image Figure Based on the findings shown in the CT image (Figure 3), what is the next BEST step in the patient s management? A. Coronary artery bypass grafting B. Coronary artery angioplasty C. Medical management D. Coronary artery stenting Transverse image from an FDG-PET CT scan shows absence of uptake in the anteroseptal and septal portions of the left ventricular myocardium, consistent with transmural infarct. A: Coronary artery bypass grafting would not improve cardiac function based on the image provided as there is no viable myocardium in the affected area. B: Percutaneous coronary intervention would not improve cardiac function based on the image provided as there is no viable myocardium in the affected area. C: Medical management to optimize the patient's cardiac function is this patient's best choice as surgical or percutaneous intervention would offer no benefit. D: Percutaneous coronary intervention would not improve cardiac function based on the image provided as there is no viable myocardium in the affected area.

4 Figure What abnormality is depicted in this CT image (Figure 4)? A. Pulmonary agenesis B. Pulmonic stenosis C. Absent pericardium D. SVC thrombus Contrast-enhanced CT of the chest reveals lung tissue interposed between the aorta and the main pulmonary artery. Because this area is intrapericardial (superior pericardial recess), this finding can only be seen in the absence of the pericardium. A: Pulmonary agenesis refers to the absence of the lung, and its bronchial and vascular supply. In the setting of pulmonary agenesis, there is resultant shift of the mediastinum to the affected side. The right pulmonary artery is not visualized on this image because it is more superiorly located compared to the left pulmonary artery. The other findings of pulmonary agenesis are not present. B: Pulmonic stenosis results in dilatation of the left pulmonary artery, which is thought to be secondary to the effect of the jet of blood coursing through the stenotic pulmonary valve. The right pulmonary artery is typically spared since it arises at an angle from the main pulmonary artery whereas the left pulmonary artery continues in line with the main pulmonary artery. The main pulmonary artery and left pulmonary artery are normal in caliber in this case. C: In patients with congenital absence of the pericardium there are indirect cross-sectional imaging findings that can lead to the diagnosis. If the sternopericardial ligaments are absent, the heart is mobile and falls towards the left hemithorax. Lung tissue becomes interposed between the aorta and the main pulmonary artery, as in this example, replacing the superior aortic recess of the pericardial sac. If the defect is small, the left atrial appendage may herniate through the defect causing it to extend beyond the mediastinal margin. D: The apparent filling defect in the superior vena cava is secondary to the mixing of opacified and unopacified blood. This is a common artifact and should not be mistaken for thrombus.

5 Lateral chest radiograph Figure What is the MOST LIKELY diagnosis (Figure 5)? A. Right aortic arch with mirror image branching B. Left aortic arch with aberrant right subclavian artery C. Pulmonary artery sling D. Double aortic arch On this lateral chest radiograph, there is anterior displacement and bowing of the trachea by a mediastinal opacity occupying Raider triangle, the clear space above the aortic arch bordered by the vertebral column and posterior to the trachea and esophagus. A: The abnormality shown in the chest radiograph is caused by the aberrant course of a subclavian artery. In patients with a left aortic arch with normal origin of the great vessels or in patients with a right aortic arch with mirror image branching, the great vessels do not cause this appearance. B: This is the most common of the aortic arch vessel anomalies. In these cases, the right subclavian artery does not arise from the innominate artery but originates as the last branch from the aortic arch. The aberrant subclavian then takes a retroesophageal route to its destination. The aberrant right subclavian artery frequently arises from a dilated segment of the proximal descending aorta, the diverticulum of Kommerell, which can be mass-like on conventional radiography. C: This abnormality occurs when the left main pulmonary artery arises from the right pulmonary artery instead of originating from the main pulmonary artery. The left pulmonary artery courses cephalad to the right mainstem bronchus, and travels between the trachea and esophagus to supply the left lung. On barium esophagram, the aberrant left pulmonary artery causes an anterior impression on the midesophagus. The abnormality in this case lies at and above the aortic arch whereas the pulmonary arteries lie below the aortic arch. D: The classic double aortic arch anatomy develops when involution of the distal right fourth arch does not take place. The right and left aortic arches encircle the trachea and esophagus. Double aortic arch is better appreciated on the PA chest radiograph.

6 Figure What is the MOST LIKELY diagnosis (Figure 6)? A. Teratoma B. Lipoma C. Lipomatous hypertrophy of the interatrial septum D. Liposarcoma Axial contrast-enhanced CT image of the heart shows increased fat attenuation within the interatrial septum with sparing of the fossa ovalis. A: Cardiac teratomas are usually large tumors and are rare. B: Lipomatous hypertrophy of the interatrial septum (LHIS) has a characteristic location and dumbbellshaped appearance. It does not represent a discrete lipoma as it lacks a capsule. Histologically, LHIS is composed of brown fat and may be hypermetabolic on PET. Intracardiac lipomas do not typically involve the interatrial septum. C: Lipomatous hypertrophy of the interatrial septum (LHIS) is not a true neoplasm and histologically consists of nonencapsulated brown fat. LHIS is typically located in the interatrial septum, sparing the fossa ovalis, which causes a characteristic dumbbell-shaped appearance. D: Liposarcomas are rare tumors that usually fill the entire cardiac chamber. Often these tumors present with localized invasion of neighboring structures, demonstrate mass effect and localized metastasis.

7 Figure What abnormality is shown on this reconstructed CT image (Figure 7)? A. Truncus arteriosus B. Diverticulum of Kommerell C. Patent ductus arteriosus D. Aortic coarctation There is a vascular structure connecting the inferior aspect of the posterior aortic arch and the main pulmonary artery consistent with a patent ductus arteriosus. A: The image shows a connection between the posterior aortic arch and the main pulmonary artery consistent with patent ductus arteriosus. In truncus arteriosus, there is a single great vessel which is located over a ventricular septal defect. Two great vessels are shown in this case. B: The image shows a connection between the posterior aortic arch and the main pulmonary artery consistent with patent ductus arteriosus. The diverticulum of Kommerell occurs at the origin of an aberrant right subclavian artery arising from the aorta. There is normal great vessel anatomy in this case. C: The image shows a connection between the aorta and main pulmonary artery consistent with patent ductus arteriosus. D: The image shows a connection between the aorta and main pulmonary artery consistent with patent ductus arteriosus. The aorta is normal in appearance.

8 Axial balanced steady-state free precession Axial contrast-enhanced fat-suppressed T1W Figure 8 Figure A 42-year-old man presents with chest pain and dyspnea (Figures 8 and 9). What is the MOST LIKELY diagnosis? A. Angiosarcoma B. Pericarditis C. Pericardial cyst D. Rhabdomyoma Images A and B (axial balanced steady-state free precession and axial contrast-enhanced fat-suppressed T1) show an enhancing mass arising from the right heart, with associated pericardial fluid. A: Angiosarcoma is the most common malignant cardiac neoplasm in adults. It typically affects the right heart, often involving the pericardium. Cardiac angiosarcomas frequently demonstrate areas of heterogeneous T1 signal intensity, attributed to episodes of previous hemorrhage and typically demonstrate heterogeneous contrast enhancement. Because angiosarcomas frequently involve the pericardium, patients may present with symptoms of tamponade. B: Although an abnormal amount of pericardial fluid is present in this case, the images do not support the diagnosis of pericarditis. Pericarditis will result in thickening of the pericardium, however, it typically does not present with a discrete mass, as noted in this case. C: Although there is loculated pericardial fluid, which can mimic the appearance of a pericardial cyst, there is also an enhancing mass, consistent with neoplasm. D: Rhabdomyomas are the most common primary cardiac neoplasm in children, but are rare in adults. Rhabdomyomas typically present within the ventricular myocardium.

9 Contrast-enhanced CT of the chest reformatted into the short axis of the heart Figure What physiologic condition can be inferred by this CT image (Figure 10)? A. Increased systemic afterload B. Pulmonary venous hypertension C. Elevated right heart pressure D. Pericardial tamponade This contrast-enhanced short axis reformatted CT image shows an enlarged right ventricle with thickened walls, causing the ventricular septum to bow into the left ventricular lumen. A: Increased afterload occurs in the setting of increased aortic pressure, as can be seen in aortic valve stenosis or systemic hypertension. This typically results in concentric left ventricular hypertrophy. In this example, the left ventricle is not thick-walled, but rather is partially collapsed by the high-pressure right ventricle. B: Pulmonary venous hypertension, as typically noted in left heart failure or volume overload, is typically manifested by left atrial and left ventricular dilation. This example instead shows a small left ventricle and a dilated right ventricle. C: The image shows a thick-walled right ventricle with the ventricular septum deviated toward the lumen of the left ventricle. In the normal physiologic state, the left ventricle should retain a round configuration as viewed in the short axis plane throughout systole and diastole, owing to the left heart s higher pressure. To see the septum deviated toward the left ventricle indicates significantly elevated right heart pressures. In this case, the patient had a long-standing history of primary pulmonary hypertension. D: Tamponade may result in ventricular deformation, though this typically affects the right heart to a greater degree, owing to its lower pressure compared to the left ventricle. Also, there is no significant pericardial fluid shown in this image.

10 TI=150 msec TI=200 msec Figure 11 Figure 12 TI=250 msec TI=300 msec Figure 13 Figure Based on the images obtained 1 minute after administration of gadolinium (Figures 11-14), what is the ideal inversion time (TI) for this subject? A. 150 msec B. 200 msec C. 250 msec D. 300 msec The following short axis inversion recovery T1-weighted images were performed on a normal subject 1 minute after administration of gadolinium. Figures A and B demonstrate findings of an inversion time that is too short, manifested by central myocardial hyperintensity with a hypointense rim. Figure C demonstrates an ideal inversion time, with uniform nulling of the myocardium. Figure D demonstrates an inversion time that is too long, with the myocardium appearing diffusely intermediate in signal intensity. A: The myocardium in this example shows central relative hyperintensity with a rim of T1 hypointensity. This indicates that the TI used in this example is too short. An ideal TI will uniformly null the normal myocardium, resulting in a uniformly black appearance. B: The myocardium in this example shows central relative hyperintensity with a rim of T1 hypointensity. This indicates that the TI used in this example is too short. An ideal TI will uniformly null the normal myocardium, resulting in a uniformly black appearance. C: The myocardium in this example shows appropriate nulling, with a uniform black appearance. A 180º inversion pulse is applied to the imaged volume in delayed, contrast-enhanced viability imaging to heighten the conspicuity of abnormal enhancement. As the imaged volume undergoes T1 relaxation to realign with the main magnetic field, each component of the volume will recover to zero based on the tissue s intrinsic T1. If the imaging pulse used for the viability sequence is applied at the point where normal myocardium has recovered to zero, the normal myocardium will appear black, and pathologic enhancement will be conspicuously bright. D: The myocardium in this example is diffusely intermediate in signal intensity. This indicates that the TI is too long. An ideal TI will uniformly null the myocardium, resulting in a uniformly black appearance in normal myocardium.

11 99. For a 3D cardiac CT image dataset acquired at 0.5 mm slice thickness, which of the following is MOST LIKELY to occur if the reconstruction interval is altered from 0.5 mm to 0.3 mm? A. Increased patient dose B. Decreased patient dose C. Increased data set D. Increased scan time A. Patient dose is unaffected by the changes in reconstruction interval as it does not affect scan acquisition. B. Patient dose is unaffected by the changes in reconstruction interval as it does not affect scan acquisition. C. If the reconstruction interval is decreased, it results in higher number of slices yielding higher image size for 3D images. D. Changes in reconstruction interval only affects reconstruction time but not the scan time Which one of the following conditions is MOST closely associated with aortic dissection? A. Systemic hypertension B. Bicuspid aortic valve C. Marfan s syndrome D. Prior cardiac surgery 101. Where is the crista supraventricularis located? A. At the junction of the left atrial appendage and the left pulmonary vein B. Between the right ventricular free wall and the interventricular septum C. Between the inflow and outflow portions of the right ventricle D. Between the right atrial appendage and the right atrium A: The Coumadin ridge is located at the junction of the left atrial appendage and the left superior pulmonary vein and may cause the appearance of a filling defect. B: The moderator band is located at the apex of the right ventricle and extends from the right ventricular free wall to the interventricular septum. C: The crista supraventricularis is one of a series of muscular bands that separates the inflow and outflow portions of the right ventricle. D: The crista terminalis is a muscular ridge of varying prominence that separates the trabeculated right atrial appendage from the smooth-walled right atrium.

12 102. What is the MOST common cause of mitral valve stenosis? A. Left atrial myxoma B. Endocarditis C. Mitral annular calcification D. Rheumatic heart disease A: Although a left atrial myxoma can prolapse through the mitral valve and result in functional mitral valve stenosis, it is not the most common cause of mitral stenosis. B: Infective endocarditis with large vegetations may cause obstruction of the mitral valve orifice. However, the most common cause of mitral stenosis is rheumatic fever. C: Mitral annular calcification is a very common occurrence, particularly in older women. Only in severe cases does mitral annular calcification lead to mitral valve leaflet thickening and subsequent mitral stenosis. D: Rheumatic heart disease is the most common cause of mitral stenosis and usually develops 5-10 years following rheumatic endocarditis.

13 103. Regarding congenital absence of the pericardium, which of the following statements is TRUE? A. Right pericardial involvement is more common than left. B. Most patients have associated cardiopulmonary defects. C. Total absence of the pericardium occurs most commonly. D. Partial defects risk cardiac herniation and strangulation. A: Total or partial absence of the left pericardium accounts for about 70% of cases. This is believed to be caused by early atrophy of the left duct of Cuvier, which supplies the embryonic pleuropericardial membrane. The right duct of Cuvier forms the superior vena cava, and, as a result, the right pleuropericardial membrane usually receives adequate nutrition. B: Only about 30% of individuals with congenital pericardial absence have associated defects such as patent ductus arteriosus, atrial septal defect, tetralogy of Fallot, and pulmonary sequestration. C: Total congenital absence of the pericardium is extremely rare. D: Although generally a benign condition, cardiac herniation with or without strangulation can occur when a partial congenital pericardial defect is present. With a partial left pericardial defect, the left atrial appendage is at risk for strangulation Regarding myocardial bridges, which of the following statements is TRUE? A. The circumflex artery is most commonly affected. B. They require surgical treatment. C. CT depicts them better than angiography. D. They occur in less than 10% of autopsy specimens. A: Myocardial bridges are most commonly encountered affecting the left anterior descending artery. B: In most cases, myocardial bridges are clinically silent. C: Because multiplanar reformatted images can be acquired from the original CT dataset, CT is better able to detect the intramuscular course of the coronary artery. D: In autopsy series, myocardial bridging, an intramuscular course of the coronary artery, occurs in almost 30% of specimens.

14 105. Enlargement of which of the following structures is the MOST reliable radiographic sign of pulmonary valve stenosis? A. Left pulmonary artery B. Bilateral pulmonary arteries C. Right ventricle D. Main pulmonary artery A: Enlargement of the left pulmonary artery, with or without pulmonary trunk enlargement, is the hallmark of pulmonary valve stenosis. B: Enlargement of both pulmonary arteries is characteristic of either pulmonary hypertension or overcirculation. Enlargement of the right pulmonary artery is not a feature of pulmonary valve stenosis. C: The right ventricle hypertrophies in response to the pressure caused by pulmonary valve stenosis. Ventricular dilatation only occurs if ventricular failure or tricuspid regurgitation is present. D: The pulmonary trunk can be either normal or enlarged on chest radiography in patients with pulmonary valve stenosis. Isolated pulmonary trunk enlargement can be seen in patients with idiopathic pulmonary artery dilation Which of the following structures contributes to the posterior border of the mediastinum on a normal lateral chest radiograph? A. Superior vena cava B. Inferior vena cava C. Main pulmonary artery D. Right atrium A: The superior vena cava contributes to the most superior aspect of the anterior border of the mediastinum on a lateral chest radiograph. B: The inferior vena cava contributes to the most inferior aspect of the posterior border of the mediastinum on a lateral chest radiograph. C: The main pulmonary artery contributes to the anterior border of the mediastinum on a lateral chest radiograph, and represents the superior portion of the convex curve largely created by the right ventricle. D: The right atrium is not typically seen in the lateral projection, but represents the inferior aspect of the right border of the mediastinum on a frontal chest radiograph.

15 107. Which one of the following findings is seen in the setting of constrictive pericarditis? A. Atrial collapse B. Globular configuration of the ventricles C. Dilation of the inferior vena cava D. Left ventricular hypertrophy A: Many of the findings seen in constrictive pericarditis are due to the physiologic changes that take place with impaired left ventricular filling. The impaired filling leads to dilation of the upstream chambers, the atria, and the superior and inferior vena cava. B: Many of the findings seen in constrictive pericarditis are due to the physiologic changes that take place with impaired left ventricular filling. This impaired filling leads to decreased ventricular volumes, and the ventricles typically take on a tubular configuration. C: Many of the findings seen in constrictive pericarditis are due to the physiologic changes that take place with impaired left ventricular filling. The impaired filling leads to dilation of the upstream chambers, the atria, and the superior and inferior vena cava. Normally, the superior vena cava should not be greater in diameter than the ascending aorta and the inferior vena cava should not be more than twice the diameter of the descending aorta. D: Many of the findings seen in constrictive pericarditis are due to the physiologic changes that take place with impaired left ventricular filling. This impaired filling leads to decreased ventricular volumes, and the ventricles typically take on a tubular configuration. Occasionally, constrictive pericarditis is accompanied by left ventricular atrophy, the etiology of which remains uncertain. This carries a higher degree of morbidity and mortality when present Diffuse subendocardial enhancement of the left ventricle on delayed contrast-enhanced MRI of the heart is MOST typical of what entity? A. Myocardial ischemia B. Myocardial infarction C. Amyloidosis D. Asymmetric septal hypertrophy A: Myocardial ischemia, in the absence of infarction, does not characteristically result in pathologic enhancement on delayed contrast-enhanced MRI of the heart. B: In the setting of myocardial infarction, there is enhancement of the subendocardium on delayed imaging. However, the enhancement is not diffuse and is typically confined to discrete coronary artery distributions. C: Amyloidosis is a systemic disorder that may affect the heart, resulting in a clinical picture of restrictive cardiomyopathy. At delayed contrast-enhanced MRI of the heart, amyloidosis frequently results in diffuse subendocardial enhancement. This can be differentiated from myocardial infarction by its distribution beyond coronary artery distributions. The degree of pathologic enhancement may be so significant and diffuse, that finding an appropriate inversion time to null normal myocardial signal for delayed contrast-enhanced sequences may be difficult. D: Asymmetric septal hypertrophy, or hypertrophic cardiomyopathy, may not manifest with abnormal enhancement, however when abnormal enhancement is present, it is typically confined to the septal myocardium.

16 109. Regarding sinus of Valsalva aneurysms, which one of the following statements is TRUE? A. They rarely involve the left coronary sinus. B. Hypertension is the most common acquired cause. C. Rupture usually causes pericardial tamponade. D. The majority are acquired. A: Sinus of Valsalva aneurysms occur most commonly in the right or noncoronary sinus and rarely in the left coronary sinus. B: Acquired sinus of Valsalva aneurysms are usually caused by a disruption of the aortic wall such as infection, trauma or connective tissue disorders. C: When rupture occurs, it is into the right atrium or ventricle resulting in symptoms of acute heart failure. D: Congenital sinus of Valsalva aneurysms are more common than acquired aneurysms.