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5 Cardiovascular Magnetic Resonance Imaging

Adult Cardiac MR Cases

FIGURE 5-1 Nonobstructive hypertrophic cardiomyopathy.

Cardiac MRI is used to evaluate the severity and location of hypertrophy and fibrosis in HCM. Cine imaging is used to evaluate dynamic outflow tract obstruction from the systolic anterior motion of the anterior mitral valve leaflet.

Cardiac MRI was performed to evaluate a 20-year-old white male presenting with worsening exertional dyspnea and near-syncope. His brother died suddenly at age 23. An echocardiogram showed symmetric hypertrophy without evidence of a dynamic outflow tract obstruction. A, The horizontal WB long-axis image shows diffuse hypertrophic changes of the LV walls. Postcontrast vertical (B) and horizontal (C) long-axis images demonstrate areas of hyperenhancement (arrow) from myocardial fibrosis at the cardiac apex. This fibrosis is associated with increased risk of heart failure and sudden death.

FIGURE 5-2 Valvular disease.

Though echocardiography is the primary imaging modality used to assess valvular structures, regurgitation, and stenosis, cardiac MRI is useful in patients with suboptimal echocardiographic images. Valve leaflet thickness and mobility can be assessed. In addition, quantification of valvular regurgitation may be completed using phase and volumetric techniques.

A, Mitral regurgitation. A 72-year-old African American male with longstanding hypertension presented with progressive heart failure. On cardiac MRI, this WB LV inflow view demonstrates an enlarged LV with significant mitral regurgitation, represented by the black jet in the white blood extending from the valve into the left atrium.

B, Tricuspid stenosis. A 30-year-old female presented with symptoms of progressive right heart failure, increasing abdominal pain, ascites, and lower extremity edema over the past few months. Cardiac MRI demonstrated a normal RV but thickened tricuspid valve leaflets. The right atrium is markedly enlarged, and an incidental right pleural effusion can be seen on this WB horizontal long-axis view.

C, Ebstein anomaly. Cardiac MRI demonstrates a markedly enlarged right atrium and RV on this WB horizontal long-axis view. The tricuspid valve leaflets are not well visualized. The leftward bowing of the atrial septum is consistent with increased right-sided pressures. The patient was a 70-year-old female who presented with a vague history of cardiac murmur and 6-month history of abdominal swelling and lower extremity edema. Echocardiography demonstrated inferior displacement of the septal leaflet of the tricuspid valve, a dilated right atrium and RV, and severe tricuspid regurgitation consistent with Ebstein anomaly.

FIGURE 5-3 Restrictive cardiomyopathy.

WB horizontal long-axis image obtained from a 60-year-old male whot had felt poorly for several years but had become more dyspneic over the past 3 months. The patient’s history includes Hodgkin lymphoma as a teenager with mantle radiation. Cardiac MRI, completed to help determine if the patient had restrictive cardiomyopathy versus constrictive pericarditis, demonstrated normal LV and RV cavity sizes and systolic function. Both left and right atria are massively enlarged. No significant valvular regurgitation was seen. The pericardium is of normal thickness. The patient was diagnosed with restrictive cardiomyopathy.

FIGURE 5-4 Left atrial myxoma.

A 45-year-old Native American male evaluated for a several-month history of night sweats and several episodes of positional near-syncope, particularly when he goes bowling. TTE had demonstrated a left atrial mass, and cardiac MRI confirmed that the large left atrial mass occupying the superior portion of the left atrium was a myxoma (arrows). The mass appears homogeneous and smooth with a capsule. WB vertical long-axis (A) and axial (B) images demonstrate the left atrial myxoma. Often, contrast is administered to help differentiate cardiac masses. For example, lymphomas are usually markedly enhancing, whereas myxomas usually do not significantly enhance.

FIGURE 5-5 Noncompaction cardiomyopathy.

A 35-year-old white female presented with heart failure and no prior cardiac history. TTE was technically challenging, but demonstrated a normal LV size with prominent trabeculations at the apex. WB T2-weighted images in short-axis (A), vertical long-axis (B), and horizontal long-axis (C) demonstrate a thickened LV wall secondary to thickened trabeculations. Blood is clearly viewed within the thick trabeculations. This patient was diagnosed with noncompaction cardiomyopathy.

FIGURE 5-6 Anomalous LCA.

A 20-year-old African American female presented with recurrent exertional chest pain. This fat-suppressed T2-weighted axial image reveals an abnormal course of the LCA (arrow) between the aorta and main PA trunk. This is a known risk factor for sudden cardiac death in young adults during exercise. The LCA may be compressed between the aorta and PA during episodes of increased cardiac output.

FIGURE 5-7 Cor triatriatum sinistrum.

A 27-year-old white male presented with dyspnea and a heart murmur. The T1-weighted axial cardiac MRI shown here demonstrates cor triatriatum sinistrum. The left atrium is partitioned into two segments by a fibromuscular membrane (arrow). The posterosuperior portion usually receives the pulmonary venous return, and the anteroinferior portion contains the left atrial appendage and mitral valve. In this image, the LV appears normal in size. The RV is prominent with low normal function on cine imaging. Depending on the presence and size of the communication(s) present, pulmonary hypertension may develop secondary to obstruction of pulmonary venous flow. In symptomatic patients, the membrane can be surgically resected. There are several theories of development of cor triatriatum sinistrum, including malincorporation, malseptation, and entrapment.

Adult Congenital MR Cases

FIGURE 5-8 Aortic arch anomalies can occasionally escape detection until adulthood if symptoms are mild. A, A double aortic arch that forms a vascular ring (posterior view of surface-rendered image). Black blood axial (B) and coronal (C) images of a right aortic arch with a Kommerell diverticulum and mirror image branching of the brachiocephalic vessels. This anomaly also forms a vascular ring. Kommerell diverticulum is the bulb-like dilatation of the distal origin of the left subclavian artery from the descending thoracic aorta. D, A left aortic arch with retro-esophageal right subclavian artery. This is not a vascular ring but may cause mild dysphagia. 1, Ascending aorta; 2, descending aorta, with Kommerell diverticulum in part C; 3, trachea at bifurcation; 4, right arch; 5, left arch; 6, descending aorta; 7, anomalous right subclavian artery; 8, SVC.

FIGURE 5-9 Associated defects of aortic arch anomalies should always be potentially investigated. A, A surface-rendered posterior view of a patient who has previously undergone subclavian flap repair of coarctation. Note absence of a left subclavian artery and bilateral SVC. B, In this three-chamber view, an enlarged aortic root and ascending aortic aneurysm are apparent. C, The aortic valve was determined to be bicuspid on short-axis imaging. Coarctation of the aorta is commonly associated with bicuspid aortic valve. 1, Left SVC; 2, right SVC; 3, descending aorta; 4, aortic root enlargement; 5, bicuspid aortic valve; 6, left atrium; 7, right atrium; 8, RV; 9, LV.

FIGURE 5-10 When a child is born with inadequate ventricle or AV valve size, a 1½ ventricle repair may be completed. Horizontal (A) and short-axis (B) images of the cardiac chambers. In this patient, the RV was dysfunctional and the right atrium was enlarged. Therefore, the patient underwent a Glenn operation, which allows blood to flow passively from the SVC to the PAs (arrow). The pulmonary arteries are confluent in this patient; however, secondary to asymmetric gadolinium enhancement, part C lends the impression of a classic unidirectional Glenn shunt, instead of a bidirectional Glenn shunt. After the Glenn shunt, the RV only receives IVC flow and pumps this blood through the pulmonary artery. 1, Right atrium; 2, left atrium; 3, RV; 4, LV; 5, SVC; 6, right PA; 7, right pulmonary veins.

FIGURE 5-11 A patient with tricuspid atresia and a tiny RV who has undergone a staged palliation culminating in a Fontan procedure. A, The Fontan procedure results in venous blood from both the SVC and IVC passively flowing to the pulmonary circulation, bypassing a pumping chamber. Horizontal long-axis (B), short-axis (C), and three-chamber (D) images of the functional single ventricle that pumps to the systemic circulation. The TV is absent and the RV is hypoplastic and hypertrophied. 1, Left atrium; 2, LV; 3, hypoplastic/hypertrophied RV; 4, pulmonary veins; 5, Fontan pathway; 6, PAs.

FIGURE 5-12 Cardiovascular MRI is an excellent tool to follow aortopathies such as occur with Marfan syndrome. These WB short-axis (A) and three-chamber (B) images depict a trileaflet aortic valve with aortic root dilation. 1, Aortic valve in systole; 2, aortic root; 3, left atrium; 4, LV; 5, mitral valve.

FIGURE 5-13 Many patients born with D-transposition before the late 1980s underwent surgical repair with a Mustard or Senning operation. This operation leaves the great vessels transposed and places the RV as the systemic pump. This operation involves placing an intra-atrial baffle to direct pulmonary venous return to the systemic RV and systemic venous blood to the subpulmonary LV. A, Short-axis view of the ventricles showing RV enlargement, hypertrophy, and flattening of the septum. B, Horizontal long-axis image demonstrating the anterior RV receiving flow via the pulmonary views pathway. C, Axial (short-axis) image of pulmonary venous pathway. D, Sagittal view of the cardiac chambers. Note the RV is the systemic pumping chamber connected to the aorta. It is severely enlarged and hypertrophied. The LV is connected to the pulmonary artery. Note the absence of hypertrophy of this chamber’s walls. 1, RV; 2, LV; 3, pulmonary venous pathway; 4, systemic venous pathway; 5, aorta (anterior); 6, PA (posterior); 7, LCA.

FIGURE 5-14 ASDs are occasionally associated with PAPVR. Both result in right-sided volume overload and RV enlargement. A, Paraxial image demonstrating the RUPV draining into the right atrium. B, Horizontal long-axis (four-chamber) image showing the right lower pulmonary vein emptying into a massively enlarged right atrium. A large secundum ASD is present. Also note the biventricular hypertrophy and RV cavity dilatation. Anomalous pulmonary venous drainage is relatively rare in patients with secundum ASDs. However, sinus venosus ASDs are nearly always associated with PAPVR, most commonly involving the RUPV, as shown in part C. In this oblique coronal view, the RUPV is draining into a severely enlarged right atrium. 1, Right atrium; 2, left atrium; 3, RV; 4, LV; 5, aorta; 6, right upper pulmonary vein; 7, right lower pulmonary vein; 8, ASD; 9, PA.

FIGURE 5-15 Postoperative evaluation of tetralogy of Fallot frequently involves the use of cardiac MRI. After transannular repair of the RVOT, patients may develop significant RV pathology, including enlargement, fibrosis, poor function, or areas of dyskinesis. MRI can also be used to quantify flow and calculate a regurgitant fraction. This data is important in decision making for replacement of the pulmonary valve. A, WB paracoronal image demonstrating marked RV enlargement in a patient with a history of repair for tetralogy of Fallot. B and C, Short-axis images from different patients with tetralogy of Fallot repairs showing RV enlargement. The patient in part C also has developed aneurismal dilatation of the RVOT. D, Delayed enhancement short-axis image showing fibrosis in the RV outflow region. 1, RV; 2, LV; 3, aorta; 4, delayed enhancement; 5, RVOT aneurysm.

FIGURE 5-16 Aortic coarctation can be treated surgically or in older children and adults by transcatheter therapy. Aortic coarctation beyond the early childhood years is frequently treated with endovascular stent placement. Current stents (arrows) may cause significant signal void on WB images; however, useful information can be obtained using black blood images. Sagittal black blood (A) and white blood (B) images in a patient after endovascular treatment of aortic coarctation. Note the signal void caused by the stent on the WB image. Cardiac MRI/MRA is the modality of choice to longitudinally follow repaired coarctations; the major concerns are recurrent coarctation and aneurysm formation.

FIGURE 5-17 Native coarctation presents with upper extremity hypertension. In an older child or young adult extensive aortic collaterals are often present with enlargement of vessels proximal to the obstruction such as internal mammary arteries. Aortic coarctation is frequently associated with relative hypoplasia of the transverse aortic arch. A, Gadolinium-enhanced MRA in the sagittal plane. B, Surface-rendered image viewed from the left chest perspective. Note the large internal mammary arteries (arrows) and hypoplasia of the transverse arch just before the coarctation. If left untreated, significant transverse arch hypoplasia may be associated with right arm and cerebral circulation hypertension.

FIGURE 5-18 Ostium secundum ASD can sometimes escape detection until adulthood. Short-axis (A) and horizontal long-axis (B) images demonstrate the marked RV enlargement characteristically seen in patients with large unrepaired ASDs. In part B, the secundum ASD is readily apparent. It can also be used to define tissue rims if consideration of transcatheter intervention is entertained. The inferior or IVC rim is the most difficult to image with echocardiography but is shown well on appropriate MRI images, as noted in part C. D, Enface imaging of the atrial septum can provide information about the defect shape and relationship if more than one defect is suspected. 1, Right atrium; 2, left atrium; 3, ASD; 4, inferior rim; 5, RV; 6, LV.

Peripheral Vascular MRA Cases

FIGURE 5-19 Infrarenal AAA with bilateral iliac stenoses.

A 67-year-old Native American male presented with progressive lower extremity claudication and several necrotic toes. Patient had a history of diabetes, tobacco use, and hyperlipidemia. This single coronal postcontrast MIP MRA shows a large infrarenal AAA with mild circumferential clot (arrow). The aneurysm begins 5.6 mm inferior to the main right renal artery and extends 7.8 cm inferiorly to the iliac bifurcation. The maximum diameter is 4.7 cm. There is a 70% stenosis of the proximal right common iliac artery and 40% stenosis of the proximal left common iliac artery.

FIGURE 5-20 Infrarenal AAA with right common iliac artery stent.

A 72-year-old African American male with known PVD, CAD, hypertension, and diabetes mellitus underwent MRA to further evaluate an AAA found on a duplex study. He had previous right lower extremity claudication and had undergone placement of a right common iliac stent. He had emboli to both feet recently. Single coronal noncontrast MIP MRA shows a large infrarenal AAA that begins 4.1 cm inferior to the origin of the left main renal artery and extends to the iliac bifurcation. The maximum dimension of the AAA is 5.3 cm. Stent artifact is seen in the proximal right common iliac artery (arrow); therefore, it is not possible to evaluate the right SFA at the stent location.

FIGURE 5-21 Carotid occlusive disease with significant left internal carotid artery stenosis: two coronal postcontrast MIP MRA.

A 65-year-old white male with hypertension and diabetes presented with transient right hand weakness. Carotid duplex imaging suggested a severe (60% to 79%) stenosis of the proximal left ICA. A and B, With just slightly different angles, are two coronal postcontrast MIP MRA images showing a 70% to 80% stenosis of the proximal left ICA (arrows). There is also a 40% to 50% stenosis of the proximal left subclavian artery (arrowheads). In addition, there is a 30% stenosis of the proximal right ICA that is not well-visualized on these images.

FIGURE5-22 Infrarenal AAA with occluded distal aorta and bilateral common iliac stents.

A 56-year-old Native American male who uses tobacco and has uncontrolled hypertension and diabetes presented with progressive bilateral lower extremity claudication. He has had previous treatment of PVD with stents placed to both common iliac arteries. Abdominal ultrasound diagnosed a large AAA. This coronal postcontrast MIP MRA delineates a large infrarenal AAA arising 3.2 cm below the origins of the renal arteries, extending 6.2 cm distally, and having a maximum dimension of 4 cm in an oblique plane. There is minimal clot within the aneurysm. Note that the aorta distal to the aneurysm is occluded.

FIGURE 5-23 Bilateral occluded superficial femoral arteries.

A 70-year-old white female with hypertension and hyperlipidemia presented with resting and exercise-induced bilateral lower extremity discomfort. She has had progressive claudication over the years, which has become more noticeable over the past few months. Additionally, she now has intermittent rest discomfort. This coronal postcontrast MIP MRA demonstrates 100% occlusion of the proximal right and left SFAs, which reconstitute distally (arrows). Corkscrew arteries are present, suggestive of chronic occulusion with collateral development.

FIGURE 5-24 Right renal artery stenosis with stenosis of the superior mesenteric artery.

A 22-year-old white female with a history of Takayasu arteritis is evaluated for hypertension and abdominal pain. She has a history of cold, cyanotic hands as well as pain in both lower extremities. On occasion, she also has abdominal pain. Coronal noncontrast MIP MRA shows thickening of the abdominal aortic wall and narrowing of the aortic lumen beginning at the level of the superior mesenteric artery and extending distally to the bifurcation (the narrowing is best visualized distally). She has a 60% stenosis of the proximal right renal artery (arrow) and an 80% to 90% stenosis of the proximal superior mesenteric artery, which is not well visualized on this image.

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5 Cardiovascular Magnetic Resonance Imaging

Adult Cardiac MR Cases

FIGURE 5-1 Nonobstructive hypertrophic cardiomyopathy.

Cardiac MRI is used to evaluate the severity and location of hypertrophy and fibrosis in HCM. Cine imaging is used to evaluate dynamic outflow tract obstruction from the systolic anterior motion of the anterior mitral valve leaflet.

Cardiac MRI was performed to evaluate a 20-year-old white male presenting with worsening exertional dyspnea and near-syncope. His brother died suddenly at age 23. An echocardiogram showed symmetric hypertrophy without evidence of a dynamic outflow tract obstruction. A, The horizontal WB long-axis image shows diffuse hypertrophic changes of the LV walls. Postcontrast vertical (B) and horizontal (C) long-axis images demonstrate areas of hyperenhancement (arrow) from myocardial fibrosis at the cardiac apex. This fibrosis is associated with increased risk of heart failure and sudden death.

FIGURE 5-2 Valvular disease.

Though echocardiography is the primary imaging modality used to assess valvular structures, regurgitation, and stenosis, cardiac MRI is useful in patients with suboptimal echocardiographic images. Valve leaflet thickness and mobility can be assessed. In addition, quantification of valvular regurgitation may be completed using phase and volumetric techniques.

A, Mitral regurgitation. A 72-year-old African American male with longstanding hypertension presented with progressive heart failure. On cardiac MRI, this WB LV inflow view demonstrates an enlarged LV with significant mitral regurgitation, represented by the black jet in the white blood extending from the valve into the left atrium.

B, Tricuspid stenosis. A 30-year-old female presented with symptoms of progressive right heart failure, increasing abdominal pain, ascites, and lower extremity edema over the past few months. Cardiac MRI demonstrated a normal RV but thickened tricuspid valve leaflets. The right atrium is markedly enlarged, and an incidental right pleural effusion can be seen on this WB horizontal long-axis view.

C, Ebstein anomaly. Cardiac MRI demonstrates a markedly enlarged right atrium and RV on this WB horizontal long-axis view. The tricuspid valve leaflets are not well visualized. The leftward bowing of the atrial septum is consistent with increased right-sided pressures. The patient was a 70-year-old female who presented with a vague history of cardiac murmur and 6-month history of abdominal swelling and lower extremity edema. Echocardiography demonstrated inferior displacement of the septal leaflet of the tricuspid valve, a dilated right atrium and RV, and severe tricuspid regurgitation consistent with Ebstein anomaly.

FIGURE 5-3 Restrictive cardiomyopathy.

WB horizontal long-axis image obtained from a 60-year-old male whot had felt poorly for several years but had become more dyspneic over the past 3 months. The patient’s history includes Hodgkin lymphoma as a teenager with mantle radiation. Cardiac MRI, completed to help determine if the patient had restrictive cardiomyopathy versus constrictive pericarditis, demonstrated normal LV and RV cavity sizes and systolic function. Both left and right atria are massively enlarged. No significant valvular regurgitation was seen. The pericardium is of normal thickness. The patient was diagnosed with restrictive cardiomyopathy.

FIGURE 5-4 Left atrial myxoma.

A 45-year-old Native American male evaluated for a several-month history of night sweats and several episodes of positional near-syncope, particularly when he goes bowling. TTE had demonstrated a left atrial mass, and cardiac MRI confirmed that the large left atrial mass occupying the superior portion of the left atrium was a myxoma (arrows). The mass appears homogeneous and smooth with a capsule. WB vertical long-axis (A) and axial (B) images demonstrate the left atrial myxoma. Often, contrast is administered to help differentiate cardiac masses. For example, lymphomas are usually markedly enhancing, whereas myxomas usually do not significantly enhance.

FIGURE 5-5 Noncompaction cardiomyopathy.

A 35-year-old white female presented with heart failure and no prior cardiac history. TTE was technically challenging, but demonstrated a normal LV size with prominent trabeculations at the apex. WB T2-weighted images in short-axis (A), vertical long-axis (B), and horizontal long-axis (C) demonstrate a thickened LV wall secondary to thickened trabeculations. Blood is clearly viewed within the thick trabeculations. This patient was diagnosed with noncompaction cardiomyopathy.

FIGURE 5-6 Anomalous LCA.

A 20-year-old African American female presented with recurrent exertional chest pain. This fat-suppressed T2-weighted axial image reveals an abnormal course of the LCA (arrow) between the aorta and main PA trunk. This is a known risk factor for sudden cardiac death in young adults during exercise. The LCA may be compressed between the aorta and PA during episodes of increased cardiac output.

FIGURE 5-7 Cor triatriatum sinistrum.

A 27-year-old white male presented with dyspnea and a heart murmur. The T1-weighted axial cardiac MRI shown here demonstrates cor triatriatum sinistrum. The left atrium is partitioned into two segments by a fibromuscular membrane (arrow). The posterosuperior portion usually receives the pulmonary venous return, and the anteroinferior portion contains the left atrial appendage and mitral valve. In this image, the LV appears normal in size. The RV is prominent with low normal function on cine imaging. Depending on the presence and size of the communication(s) present, pulmonary hypertension may develop secondary to obstruction of pulmonary venous flow. In symptomatic patients, the membrane can be surgically resected. There are several theories of development of cor triatriatum sinistrum, including malincorporation, malseptation, and entrapment.

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