CT and MR imaging findings in patients with acquired heart disease at risk for sudden cardiac death.

Noninvasive imaging is an important screening and diagnostic tool in conditions associated with sudden cardiac death. The most common cause of sudden cardiac death is coronary artery disease, with myocarditis, cardiac sarcoidosis, and dilated and infiltrative cardiomyopathies being less common acquired causes. Common risk factors for sudden cardiac death, regardless of the disease process, include severe ventricular dysfunction and the presence of macroscopic scar seen at delayed contrast material-enhanced imaging. Recent advances in electrocardiographically (ECG) gated cardiac magnetic resonance (MR) imaging and multidetector computed tomography (CT) have led to increased referrals for cross-sectional imaging; thus, cardiac radiologists should be familiar with the disease entities associated with sudden cardiac death. Inflammatory processes and cardiomyopathies are best depicted with cardiac MR imaging. Steady-state free precession cine sequences coupled with inversion-recovery prepared gradient-echo T1-weighted sequences performed after the intravenous administration of gadolinium-based contrast material should form the basis of cardiac MR imaging protocols for cardiomyopathy. A clinical history that is suggestive of myocardial ischemia, specific requests to exclude coronary artery disease, or contraindications for MR imaging may imply that multidetector CT would be more appropriate. Nevertheless, both cardiac MR imaging and ECG-gated multidetector CT offer robust diagnosis and risk stratification for individual disease processes associated with sudden cardiac death.

Under-reporting of osteoporotic vertebral fractures on computed tomography.

PURPOSE: Osteoporotic vertebral fractures are frequently asymptomatic. They are often not diagnosed clinically or radiologically. Despite this, prevalent osteoporotic vertebral fractures predict future osteoporotic fractures and are associated with increased mortality and morbidity. Appropriate management of osteoporosis can reduce future fracture risk. Fractures on lateral chest radiographs taken for other conditions are frequently overlooked by radiologists. Our aim was to assess the value of computed tomography (CT) in the diagnosis of vertebral fracture and identify the frequency with which significant fractures are missed. MATERIALS AND METHODS: The thoracic CT scans of 100 consecutive male and 100 consecutive female patients over 55 years were reviewed. CT images were acquired on General Electric Lightspeed multi-detector (MD) CT scanners (16 or 32 row) using 1.25mm slice thickness. Midline sagittal images were reconstructed from the 3D volume images. The presence of moderate (25-40% height loss) or severe (>40% height loss) vertebral fractures between T1 and L1 was determined using an established semi-quantitative method and confirmed by morphological measurement. Results were compared with the formal CT report. RESULTS: Scans of 192 patients were analysed (95 female; 97 male); mean age 70.1 years. Thirty-eight (19.8%) patients had one or more moderate to severe vertebral fractures. Only 5 (13%) were correctly reported as having osteoporotic fractures in the official report. The sensitivity of axial CT images to vertebral fracture was 0.35. CONCLUSION: Incidental osteoporotic vertebral fractures are under-reported on CT. The sensitivity of axial images in detecting these fractures is poor. Sagittal reformations are strongly recommended to improve the detection rate.

MR imaging of cardiac tumors.

Magnetic resonance (MR) imaging is an important tool in the evaluation of cardiac neoplasms. T1-weighted, T2-weighted, and gadolinium-enhanced sequences are used for anatomic definition and tissue characterization, whereas cine gradient-echo imaging is used to assess functional effects. Recent improvements in pulse sequences for cardiac MR imaging have led to superior image quality, with reduced motion artifact and improved signal-to-noise ratio and tissue contrast. Although there is some overlap in the MR imaging appearances of cardiac tumors, particularly of primary malignancies, differences in characteristic locations and features should allow confident differentiation between benign and malignant tumors. Indicators of malignancy at MR imaging are invasive behavior, involvement of the right side of the heart or the pericardium, tissue inhomogeneity, diameter greater than 5 cm, and enhancement after administration of gadolinium contrast material (as a result of higher tissue vascularity). Concomitant pericardial or pleural effusions are rare in benign processes but occur in about 50% of cases of malignant tumors. MR imaging offers improved resolution, a larger field of view, and superior soft-tissue contrast compared with those of echocardiography, suggesting that knowledge of the MR imaging features of cardiac neoplasms is important for accurate diagnosis and management.