Vasculitis with Giant Coronary Artery Aneurysms: Role of Magnetic Resonance Imaging

Description of Clinical Presentation: A 6-year-old boy presented with a 4-month history of subacute fevers, polyarthralgia, weight loss, bilateral uveitis, headaches, and a heart murmur. Initial evaluation showed pancytopenia and bone marrow biopsy was negative. Initial screening echocardiogram and ECG were normal, and whole body magnetic resonance imaging (MRI) demonstrated normal caliber aorta. He had elevated inflammatory markers throughout his course without a unifying diagnosis.

He returned two months after initial presentation and repeat echocardiogram showed severe aneurysmal dilatation of the left main and left descending coronary arteries and irregularity of the distal descending aorta concerning for vasculitis. MR angiography of the chest, abdomen, and pelvis was ordered due to concern for vasculitis.

Diagnostic Techniques and Their Most Important Findings: MR angiography of the chest, abdomen, and pelvis (SIGNA Artist, GE Health, 1.5T) was performed. High resolution, post-contrast cardiac-gated 3D SSFP imaging of the chest (3D Whole Heart) was obtained and demonstrated marked irregularity and fusiform dilation of the aorta extending from the aortic arch through the iliac bifurcation (Image 1). There was severe dilatation of the left main coronary artery and proximal left anterior descending artery with normal sized coronary at the bifurcation (Image 2). Tissue characterization with fat-saturated pre- and post-contrast T1 weighted and T2 weighted sequences was performed. These demonstrated marked aortic wall thickening and enhancement consistent with active inflammation (Image 3). Findings were felt to be consistent with Takayasu arteritis with coronary involvement. He was started on heparin and methylprednisone and transitioned to clopidogrel, aspirin, rivaroxaban, optic and systemic prednisone, and infliximab infusion as an outpatient.

Learning Points from this Case: Takayasu arteritis (TAK) is a rare, inflammatory disorder involving the aorta and its branches, which is commonly characterized by thickening of arterial walls and narrowing or occlusion in the later stages of the disease.^1-4 TAK most commonly affects females in their second and third decades of life.² It is often difficult to diagnose due to non-specific signs and symptoms.³ Coronary involvement has been reported in up to 58% of patients, is more common in younger patients, and is associated with more severe disease.⁵ Patients will often present in the chronic phase with effects of tissue ischemia.⁴ MR angiography allows for detection and characterization of small and large vessel vasculitis etiologies including TAK while eliminating exposure to ionizing radiation, and is a means to monitor the disease progression and response to therapy over time.⁶ Early detection of TAK is vital to optimizing treatment and reducing need for surgical correction. This case highlights the utility of gated chest MR angiography in the early detection of TAK.

Image 1: Marked irregularity and fusiform dilation of the aorta extending from the aortic arch through the iliac bifurcation.
Image 2: Severe dilatation of the left main coronary artery and proximal left anterior descending artery with normal sized coronary at the bifurcation.
Image 3: Pre- and post-LAVA of descending aorta showing marked aortic wall thickening and enhancement consistent with active inflammation.