Magnetic resonance coronary angiography: Comparison between a Gd-BOPTA- and a Gd-DTPA-enhanced spoiled gradient-echo sequence and a non-contrast-enhanced steady-state free-precession sequence

Background: Several studies have demonstrated that the administration of contrast agents is advantageous in magnetic resonance coronary angiography (MRCA). Purpose: To compare a non-contrast-enhanced steady-state free-precession (SSFP) with a contrast-enhanced inversion recovery spoiled gradient-echo (IR-GE) sequence using two different contrast agents for MRCA. Material and Methods: Eight healthy volunteers were examined on a 1.5T MR scanner. For non-contrast-enhanced MRCA, a breath-hold three-dimensional (3D) SSFP sequence (repetition/echo time [TR/TE] 3.9/1.7 ms, flip angle [FA] 65) was used. Contrast-enhanced MRCA was performed repetitively in two imaging sessions over 30 min after injection of 0.2 mmol/kg body weight gadobenate dimeglumine (Gd-BOPTA) or gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) using a breath-hold 3D IR-GE sequence (TR/TE 4.1/1.7 ms, FA 15). The signal-to-noise ratios (SNR) of the coronary arteries, as well as the contrast-to-noise ratios (CNR) between coronary arteries and perivascular tissue, were calculated for all images. Blood T 1 values were repetitively estimated over 30 min using an SSFP sequence with incrementally increasing inversion times (TR/TE 2.4/1.0 ms, FA 50). Results: Gd-BOPTA-enhanced images showed significantly (P0.05) higher SNR and CNR compared to Gd-DTPA-enhanced images for all times after contrast injection (SNR: 1 min post injection [PI] 26.44.2 vs. 16.23.1; CNR: 1 min PI 21.43.7 vs. 13.22.6). Compared to the SSFP images, the Gd-BOPTA-enhanced images showed higher CNR values for all times after injection (1 min PI 21.43.7 vs. 13.85.5; P0.05), whereas the Gd-DTPA-enhanced images did not (1 min PI 13.22.6 vs. 13.85.5; P0.05). Blood T 1 estimates were not significantly different for either agent 1 min after administration (P0.05), but they were significantly lower for Gd-BOPTA (P0.05) from 7 to 25 min after injection. Conclusion: Compared to non-contrast-enhanced SSFP images, only Gd-BOPTA-enhanced images show a significantly improved contrast between the coronary arteries and the surrounding tissue.