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The evaluation and diagnosis of thoracic aortic disease using magnetic resonance imaging, including magnetic resonance angiography, is assuming an increasing role in clinical practice. Comparison with other modalities, including computed tomography and echocardiography, is discussed. Newer magnetic resonance imaging techniques, including 3-D breath-hold time-of-flight sequences are highlighted, as well as imaging strategies using standard magnetic resonance imaging techniques. Thoracic aortic disease entities covered include aneurysm, dissection, penetrating ulcers and intramural hematoma, aortitis and infection, tumors, and congenital aortic disease.

Congenital variations in the development of the thoracic aorta are common. Although there is a spectrum of disease in all age groups, arch anomalies that present in childhood and those that present in the adult tend to be of differing types. Imaging of the arch and its branches, the descending aorta, and the ductus arteriosus or ligamentum arteriosum define the morphology of the arch and permit a reasonable prediction of accompanying congenital heart disease and/or vascular ring.

To evaluate right ventricular abnormalities with magnetic resonance (MR) imaging in patients with arrhythmia but without arrhythmogenic dysplasia.In 53 patients being evaluated for right ventricular arrhythmia and 15 control subjects, MR imaging was performed to evaluate fixed thinning, fatty replacement, or reduced systolic wall thickening or motion. A diagnosis of idiopathic right ventricular outflow tract tachycardia or indeterminate was assigned for each patient, and the severity of arrhythmia was categorized.Right ventricular abnormalities were revealed in 32 (60%) of the 53 patients: fixed thinning in 27 (84%), fatty replacement in eight (25%), and reduced wall thickening or motion in 31 (97%). Right ventricular abnormalities were found in 35 (76%) of 46 patients with idiopathic right ventricular outflow tract tachycardia and in seven (39%) of 18 patients with indeterminate diagnoses (P = .022).Mild right ventricular abnormalities are likely sources for arrhythmias, even in the absence of arrhythmogenic right ventricular dysplasia.

To evaluate magnetic resonance (MR) imaging findings of intramural hematoma of the thoracic aorta and their relationship to prognosis.MR images of 22 patients with intramural hematoma of the thoracic aorta were reviewed retrospectively. Site, thickness, degree of mural involvement, and signal intensity on spin-echo (SE) and cine gradient-echo (GRE) images of the hematoma were noted. MR findings of patients who did and those who did not develop complications were compared.Hematoma site was the only MR finding that correlated significantly with patient outcome. Complication frequencies in four (80%) of five patients with hematoma of the ascending aorta (type A) and in two (12%) of 17 patients with hematoma of the descending aorta (type B) were significantly different (P = .009). There were moderately strong correlations between days after symptom onset and signal intensity of the hematoma on SE (r = 0.78) and GRE (r = 0.72) images. MR images of two of three patients who developed early-subacute complications showed signal intensity changes of the hematoma that were consistent with recurrent bleeding.Patients with MR findings consistent with type A intramural hematoma of the thoracic aorta should undergo surgery. In cases of type B intramural hematoma of the thoracic aorta, MR imaging can be useful for detecting complete resolution or impending complications of the hematoma.