Purpose: To assess the impact of integrated parallel acquisition technique (iPAT) on signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), venous contamination, and overall image interpretability for peripheral magnetic resonance (MR) angiography with use of a dedicated phased-array coil system.
Materials and methods: Three-dimensional contrast material-enhanced conventional MR angiography and iPAT peripheral MR angiography was performed at three stations (pelvis, thigh, calf) in 38 consecutive patients on a 1.5-T high-performance cardiovascular system (conventional MR angiography, n=19; iPAT MR angiography, n=19). A total of 29 vessel segments per patient were analyzed. For each segment, arterial, muscle, and background signal were measured; SNR and CNR were calculated; and repeated-measures analysis of variance was performed. For each of the three stations, the degree of venous contamination and the overall confidence of interpretability were analyzed with use of ordinal logistic regression analysis accounting for correlated outcome data.
Results: A total of 1,018 vessel segments were available for analysis (477 with conventional MR angiography, 541 with iPAT MR angiography). Compared with conventional MR angiography, iPAT MR angiography resulted in decreased SNR and CNR in the pelvis and thigh stations but no change in the calf station. The difference in the pelvis was statistically significant (P<.007 for SNR and P<0.01 for CNR). Venous contamination in the calf station was significantly less on iPAT MR angiography (P<.003), with no significant differences in the other stations. The overall confidence of interpretability with iPAT MR angiography was significantly better on the lower station (P<.008).
Conclusions: iPAT MR angiography leads to reduced SNR and CNR in the pelvis and thigh, but this does not affect interpretability of images obtained at these stations. The temporal gain results in significantly increased interpretability as a result of less venous contamination in the calf station. iPAT MR angiography is superior to conventional MR angiography for peripheral imaging.