Functional cardiac MR imaging with true fast imaging with steady-state free precession before and after intravenous injection of contrast medium: comparison of image quality and accuracy.

OBJECTIVE

To compare image quality and accuracy of left ventricular function of cine SSFP (steady-state free precession) images before and after injection of Gd-DTPA.

METHODS

In 30 patients T1 times of LV blood and myocardium were measured before and after injection of 0.2 mmol/kg body weight Gd-DTPA. Signal intensity of myocardium and left ventricular blood were measured on SSFP images and the contrast calculated. In 20 additional patients short axis images completely covering the left ventricle were acquired before and after injection of Gd-DTPA and parameters of left ventricular function compared. Image quality and regional function were assessed using the 17-segment model.

RESULTS

Image quality after injection of contrast medium did not significantly change compared with unenhanced images. Contrast between myocardium and LV blood decreased from 0.6 ± 0.01 to 0.4 ± 0.03 after injection while the T1 value of myocardium decreased from 1121 ± 21 ms to 389 ± 14 ms (blood 1413 ± 48 ms to 222 ± 8 ms). Assessment of regional and global left ventricular function revealed similar results before and after the injection of contrast medium.

CONCLUSION

Cine SSFP can be obtained after injection of contrast medium without loss of accuracy for regional and global LV ventricular function. This protocol can be used to decrease imaging time for thorough cardiac examination.