J P Finn

Magnetic resonance angiography demonstration of congenital heart disease in adults

OBJECTIVE There are limitations when using spin-echo MR imaging to evaluate congenital heart disease (CHD). These include limited ability to detect small shunts, long acquisition times, in-plane or slow flow signal and limited ability to represent complicated three-dimensional (3D) anatomy. However, MR angiography can image flow direction and disturbances, assess function and easily represents 3D anatomy. This may be valuable when evaluating adults with CHD. PATIENTS AND METHODS Fifty consecutive adult patients were referred for MR evaluation of possible or known CHD using time-of-flight MR angiography. Cine, breathhold and presaturation cine MR angiography were acquired as appropriate, with 3D (MIP) reconstruction of all extracardiac anomalies. RESULTS Forty-nine patients had a diagnostic examination (one was unsatisfactory because of arrhythmia). Correlation with alternative imaging (TTE = 36, TOE = 13, cardiac catheter = 16) or surgery was available in 39 patients (MR angiography correct in 36 patients). MRA demonstrated or excluded all confirmed congenital valve (12/12), aortic (9/9), and venous (7/7) anomalies. Thirty-five patients were evaluated for shunts. MR angiography detected 31/33 confirmed shunts (shunts present in 26 patients, sensitivity 94%, specificity 95%). Although not used in all cases, spin-echo was unreliable in demonstrating shunts as signal loss in the region of the secundum septum frequently mimicked atrial septal defects (reducing accuracy for excluding intracardiac shunts, specificity 58%). CONCLUSION MR angiography accurately defines intra- and extra-cardiac anatomy and is superior to spin-echo in detecting or excluding shunts. MR angiography safely and accurately demonstrates many aspects of CHD in adults.

Body magnetic resonance angiography and its effect on the use of alternative imaging--experience in 1026 patients.

Time-of-flight magnetic resonance (MR) angiography has been described for numerous applications but the number of patients described in published reports is usually relatively small. There is little information concerning the general utility of MR angiography in the body, outside the cranial circulation, or its effect on use of other imaging studies. Utilization of two-dimensional (2D) time-of-flight MR angiography over a 3 year period was reviewed to determine its accuracy and impact on other imaging modalities. Cranial and cardiac studies were excluded. Correlation was made with alternative imaging and surgical findings. Between January 1990 and December 1992 2D time-of-flight MR angiography was used to examine 1026 patients. MR angiography was used most frequently to examine the venous system. There was a slight reduction in the use of alternative imaging with two exceptions. When chest MR venography was performed, alternative imaging was completely abolished. Also, contrast portal venography was virtually eliminated. Five errors (0.2% of total MR angiography examinations) were recorded. Time-of-flight MR angiography, especially MR venography, is accurate and can replace contrast venography for abdominal and thoracic applications. Cost and limited availability means that other imaging, usually ultrasound, often precedes MR angiography.