Gadolinium contrast-enhanced three-dimensional MRA of peripheral arteries with multiple bolus injection: scan optimization in vitro and in vivo

In this study, a scanning protocol was developed to image the arterial bed of the pelvis and both legs along their entire length in patients with peri pheral arterial disease, using standard hard-and software. Three adjacent s tations are acquired consecutively, with some small overlap; per station; o ne Gadolinium contrast bolus is administered. The scanning protocol was opt imized in an in vitro phantom study. The optimal flip angle was found to be 50 degrees. Also, the optimal scan delay was chosen to be equal to the arr ival time of the contrast bolus thereby minimizing artifacts. Three contras t bolus injections showed sufficient enhancement of the vessels after image subtraction. Finally, stenosis quantification by manual caliper was perfor med by five observers in the MRA images and correlated with the percent dia meter reduction determined by quantitative angiography from corresponding X -ray images. The results of the MRA measurements were reproducible and intr a- and inter-observer variabilities were statistically non-significant (p = 0.54 and p = 0.12, respectively). Stenosis quantification performed by fou r observers showed a good correlation with the X-ray derived values (r(p) > 0.90, p < 0.02); the results from one observer were not significantly corr elated. Five patients with proven peripheral disease were investigated with this new MRA scanning protocol. The images were of good quality which allo wed adequate clinical evaluation; the original diagnoses obtained from X-ra y examinations, were confirmed with MRA. In conclusion, peripheral arterial disease can be evaluated adequately with this MR scanning protocol.