MR Imaging of the Thoracic Aorta.

Pre- and postoperative evaluation, serial follow-up studies, and screening examinations of the aorta are performed with noninvasive cross-sectional imaging modalities like CT and MR imaging. MR imaging allows for dedicated comprehensive evaluation without exposure to iodinated contrast or ionizing radiation. The additional advantage of MR imaging is that it can provide not only morphologic but also functional information. The purpose of this article is to advance knowledge and understanding of MR imaging techniques and their application to common aortic pathologies.

MR Imaging of Thoracic Veins.

MR imaging of thoracic veins is performed to evaluate the heart and thoracic vasculature. The protocol can be customized to the clinical question. In the embryo, systemic and pulmonary vein development is closely related to heart development. Congenital anomalies of the thoracic veins are strongly associated with other cardiac and situs abnormalities. Acquired venous abnormalities are often iatrogenic, or secondary to malignancy. This article discusses development and anatomy of the thoracic venous systems, clinical MR imaging methods for their evaluation, and illustrates the MR imaging appearance of congenital and acquired abnormalities of systemic thoracic veins, coronary sinus, and pulmonary veins.

Thoracic aorta (multidetector computed tomography and magnetic resonance evaluation).

Electrocardiographic gating, multidetector computed tomography (CT), dual-energy CT, parallel magnetic resonance imaging techniques, and advanced postprocessing methods are some of the many recent advancements that have revolutionized cross-sectional imaging of thoracic aorta. Imaging appearances of aortic disease can be complex and variable. Normal findings may simulate abnormalities, and many abnormalities may be asymptomatic. Knowledge and understanding of the imaging techniques, imaging findings of acute thoracic aortic syndromes, natural history of aortic diseases, and aortic surgical techniques may help to appropriately perform and interpret aorta-specific radiology studies.

Congenital and hereditary causes of sudden cardiac death in young adults: diagnosis, differential diagnosis, and risk stratification.

Sudden cardiac death is defined as death from unexpected circulatory arrest-usually a result of cardiac arrhythmia-that occurs within 1 hour of the onset of symptoms. Proper and timely identification of individuals at risk for sudden cardiac death and the diagnosis of its predisposing conditions are vital. A careful history and physical examination, in addition to electrocardiography and cardiac imaging, are essential to identify conditions associated with sudden cardiac death. Among young adults (18-35 years), sudden cardiac death most commonly results from a previously undiagnosed congenital or hereditary condition, such as coronary artery anomalies and inherited cardiomyopathies (eg, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy [ARVC], dilated cardiomyopathy, and noncompaction cardiomyopathy). Overall, the most common causes of sudden cardiac death in young adults are, in descending order of frequency, hypertrophic cardiomyopathy, coronary artery anomalies with an interarterial or intramural course, and ARVC. Often, sudden cardiac death is precipitated by ventricular tachycardia or fibrillation and may be prevented with an implantable cardioverter defibrillator (ICD). Risk stratification to determine the need for an ICD is challenging and involves imaging, particularly echocardiography and cardiac magnetic resonance (MR) imaging. Coronary artery anomalies, a diverse group of congenital disorders with a variable manifestation, may be depicted at coronary computed tomographic angiography or MR angiography. A thorough understanding of clinical risk stratification, imaging features, and complementary diagnostic tools for the evaluation of cardiac disorders that may lead to sudden cardiac death is essential to effectively use imaging to guide diagnosis and therapy.

Pilot study of cardiac magnetic resonance imaging for detection of embolic source after ischemic stroke.

BACKGROUND: Transesophageal echocardiography (TEE) is the standard for evaluating cardioembolic sources of stroke, although many strokes remain cryptogenic after TEE. Cardiac magnetic resonance (CMR) imaging may have advantages over TEE. We performed a prospective pilot study comparing CMR to TEE after stroke to assist in planning future definitive studies. METHODS: Individuals with nonlacunar stroke within 90 days of undergoing clinical TEE were prospectively identified and underwent a 1.5 Tesla research CMR scan. Exclusion criteria included >50% relevant cervical vessel stenosis and inability to undergo nonsedated CMR. A descriptive comparison of cardioembolic source (intracardiac thrombus/mass, aortic atheroma ≥ 4 mm, or patent foramen ovale [PFO]) by study type was performed. RESULTS: Twenty patients underwent CMR and TEE a median of 6 days apart. The median age was 51 years (interquartile range [IQR] 40, 63.5), 40% had hypertension, 15% had diabetes, 25% had a previous stroke/transient ischemic attack, 5% had atrial fibrillation, and none had coronary disease or heart failure. No patient had intracardiac thrombus or mass detected on either study. Aortic atheroma ≥ 4 mm thick was identified by TEE in 1 patient. CMR identified aortic atheroma as <4 mm in this patient (3 mm on CMR compared with 5 mm on TEE). PFO was identified in 6 of 20 patients on TEE; CMR found only 1 of these. CONCLUSIONS: In this pilot study, TEE identified more potential cardioembolic sources than CMR imaging. Future studies comparing TEE and CMR after stroke should focus on older subjects at higher risk for cardiac disease to determine whether TEE, CMR, or both can best elucidate potential cardioembolic sources.

Cardiovascular MR imaging of conotruncal anomalies.

Conotruncal anomalies are congenital heart defects that result from abnormal formation and septation of the outflow tracts of the heart and great vessels. The major conotruncal anomalies include tetralogy of Fallot, transposition of the great arteries, double-outlet right ventricle, truncus arteriosus, and interrupted aortic arch. Cardiovascular magnetic resonance (MR) imaging is an important modality for the evaluation of patients with these defects. Major advances in cardiovascular MR imaging equipment and techniques allow precise delineation of the cardiovascular anatomy and accurate quantitative assessment of ventricular function and blood flow. The data provided by cardiovascular MR imaging are useful for treatment planning and posttreatment monitoring, supplement information obtained with echocardiography, and in many cases obviate cardiac catheterization.

Cardiovascular magnetic resonance imaging of hypoplastic left heart syndrome in children.

Cardiovascular magnetic resonance imaging (CMR) plays an important complementary role to echocardiography and conventional angiography in the evaluation of hypoplastic left heart syndrome. This imaging modality is particularly useful for assessing cardiovascular postsurgical changes, extracardiac vascular anatomy, ventricular and valvular function, and a variety of complications. The purpose of this article is to provide a contemporary review of the role of CMR in the management of untreated and surgically palliated hypoplastic left heart syndrome in children.

Müllerian duct anomalies: comparison of MRI diagnosis and clinical diagnosis.

OBJECTIVE: The objective of our study was to assess agreement between MRI and clinical diagnosis of müllerian duct anomalies and identify causes of discrepancy. MATERIALS AND METHODS: Images of 103 patients who underwent MRI for suspected müllerian duct anomaly were reviewed. Imaging included axial T1-weighted spin-echo (SE) (TR/TE, 500/10) and sagittal, long-uterine-axis, and short-uterine-axis T2-weighted fast SE (5,000/80) sequences. Agreement between original MRI diagnosis and final clinical diagnosis was assessed using the kappa statistic. Two radiologists retrospectively reviewed all cases with inconsistent MRI and clinical diagnoses to identify causes of discrepancy. RESULTS: There was excellent agreement (kappa = 0.8) between MRI and clinical diagnoses of müllerian duct anomalies. For evaluation of the uterus, there was agreement in 83 of 103 patients, disagreement in 15 of 103, and agreement could not be determined in five of 103 because of uncertain MRI diagnoses. The main causes of disagreement were MRI diagnosis of septate uteri with two cervices clinically diagnosed as didelphic, partial septate uteri clinically diagnosed as arcuate, and complex anomalies with features of more than one class. The main difficulties for MRI were the detection of small uteri or remnants, characterization of cervical dysgenesis and rare anomalies, overestimation of cervical mucosal folds, characterization of anomalies in the presence of fibroids, and delineation of vaginal abnormalities. CONCLUSION: Despite excellent agreement between MRI and clinical diagnoses of müllerian duct anomalies, there are discrepancies and pitfalls resulting mostly from the absence of a precise and integrated classification scheme, unfamiliarity with rare and complex entities, and suboptimal depiction of some structures on MRI.

Cystic myometrial lesion in the uterus of an adolescent girl.

The clinical course and radiographic appearance of a cystic myometrial lesion in a 13-year-old adolescent girl are described. Hormone suppression with continuous oral contraceptive (OC) pills resulted in partial regression of the lesion, as well as control of symptoms.

Diagnostic imaging and vascular embolization for uterine leiomyomas.

This review article explains the relatively new therapy method of vascular embolization for leiomyomas of the uterus. The current concepts of diagnostic imaging of uterine leiomyomas with emphasis on preembolization imaging and postembolization follow-up are presented.

Effectiveness of MR imaging in characterizing small hepatic lesions: routine versus expert interpretation.

OBJECTIVE: The aim of our study was to compare the effectiveness of MR imaging characterization of small (