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.

T 1 maps obtained with modified Look-Locker inversion recovery (MOLLI) can be used to measure myocardial T 1 . We aimed to evaluate the potential of MOLLI T 1 mapping for the assessment of acute and chronic myocardial infarction (MI). A total of 24 patients with a first MI underwent MRI within 8 days and after 6 months. T 1 mapping was performed at baseline and at selected intervals between 2-20 min following administration of gadopentetate dimeglumine (Gd-DTPA). Delayed-enhancement (DE) imaging served as the reference standard for delineation of the infarct zone. On T 1 maps the myocardial T 1 relaxation time was assessed in hyperenhanced areas, hypoenhanced infarct cores, and remote myocardium. The planimetric size of myocardial areas with standardized T 1 threshold values was measured. Acute and chronic MI exhibited different T 1 changes. Precontrast threshold T 1 maps detected segmental abnormalities caused by acute MI with 96% sensitivity and 91% specificity. Agreement between measurements of infarct size from T 1 mapping and DE imaging was higher in chronic than in acute infarcts. Precontrast In present imaging techniques for in vivo infarct sizing, such as cardiac magnetic resonance (CMR) and singlephoton emission computed tomography (SPECT), the viewing window (i.e., the range of gray/color values to be selected for viewing) is determined arbitrarily before reporting, and thus requires a subjective preassessment of the images.In CMR the delayed-enhancement (DE) method produces high contrast between infarcted and noninfarcted myocardium (bright ϭ dead). The observable high contrast is reliant upon the imaging strategy employed. A preparatory inversion-recovery pulse in a T 1 -weighted gradientecho sequence nulls signal from noninfarcted myocardium, while infarcted myocardium, which retains a higher concentration of a gadolinium (Gd)-based extracellular contrast agent, returns higher signal due to its reduced spin-lattice relaxation time (T 1 time) (1). The contrast between infarcted and noninfarcted areas on the resulting images is therefore enhanced over and above the underlying physical differences in T 1 relaxation properties between these areas. The apparent degree of enhancement is dependent on the effectiveness of the nulling process, which is a function of the inversion time (TI) selected for the preparation pulse. Incomplete nulling will cause reduced contrast and create significant variation in the signal of remote myocardium, which is used as the reference to determine the threshold between infarcted and noninfarcted myocardium (2). The choice of TI therefore ultimately influences the infarct size as measured with DE techniques.T 1 -mapping CMR techniques circumvent the influences of windowing and variations in signal enhancement by directly measuring the underlying T 1 relaxation times of the different areas of the myocardium. At a given magnetic field strength, each tissue has a normal range for spinlattice T 1 relaxation time (3,4), much like the normal ranges of tissue X-ray attenuation in c...

Segment-based myocardial T1 mapping has the potential for showing differences between relaxation times in aortic regurgitation and in normal hearts, suggesting the existence of a diffuse myocardial fibrotic process.

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