Value of fat suppression in the MRI evaluation of suspected arrhythmogenic right ventricular dysplasia

OBJECTIVE: Arrhythmogenic right ventricular dysplasia (ARVD) is characterized by intramyocardial fibrofatty change. Fat suppression performed during conventional spin-echo imaging has been used to confirm fatty infiltration. The utility of fat suppression for enhancing the interpretation of studies of suspected ARVD has not previously been formally tested. We investigated the value of fat suppression for enhancing the interpretation of intramyocardial fatty infiltration. MATERIALS AND METHODS: Twenty-six consecutive patients clinically referred for evaluation of possible ARVD underwent cardiac MRI. Two independent observers reviewed the images retrospectively. Intramyocardial areas (n = 101) that had increased signal intensity relative to normal surrounding myocardium on T1-weighted conventional spin-echo images ("index areas") were identified. The index areas were interpreted for presence of fatty infiltration using two sets of images: The first set was obtained without fat suppression, and the second set was obtained with fat suppression. Agreement between reviewers and confidence of interpretation were determined and compared. RESULTS: Interobserver agreement was measured using a 5-point scale: 1, definitely not fat; 2, probably not fat; 3, equivocal; 4, probably fat; and 5, definitely fat. The resulting kappa values were 0.35 for non-fat-suppressed images and 0.55 for fat-suppressed images. Interobserver kappa increased from 0.67 without fat suppression to 0.90 with fat suppression using a 3-point scale: 1, not fat; 2, equivocal; and 3, fat. Confidence in the diagnosis increased from 7.2 without fat suppression to 8.8 with fat suppression (p < 0.0001) on a 10-point scale ranging from 1, not confident, to 10, very confident. CONCLUSION: The use of fat-suppressed in addition to non-fat-suppressed conventional T1-weighted spin-echo imaging increased interobserver agreement and confidence in diagnosis and evaluation of intramyocardial fatty infiltration in patients who were suspected to have ARVD.     

Evaluation of efficacy of 64-slice multidetector computed tomography in patients with congenital coronary fistulas

OBJECTIVE: To evaluate the efficacy of 64-slice coronary multidetector computed tomography (MDCT) in the assessment of congenital coronary artery fistula (CCAF). METHODS: Two readers prospectively evaluated the 64-slice coronary MDCT appearances of CCAF in 10 patients (5 men and 5 women; mean age, 58.6 years; range, 19-82 years). Fistula origin, course, distal entry site, and maximal receiving chamber/vessel dimensions were determined using retrospective multisegment reconstructions at 10% increments of the cardiac cycle. RESULTS: Origin, course, and distal vessel entry site of CCAF were clearly outlined in all patients. The distal vessel draining site involved multiple small entry vessels in 5 patients and a single entry vessel in 5 patients. The right atrium in 3 patients and right ventricle in all patients were enlarged. Contrast opacification of the receiving chamber (contrast shunt sign) was detected in 4 patients, indicating patency and site of fistula entry. CONCLUSION: Cardiac 64-slice MDCT provides excellent visualization of the origin, course, and distal vessel entry site of CCAF and the size of the receiving chamber.