Non-contrast-enhanced MR angiography of the foot with flow spoiled-fresh blood imaging (FS-FBI): feasibility study and comparison of different scanning parameters

Abstract

To evaluate the feasibility of foot arteries using flow-spoiled-fresh blood imaging (FS-FBI) and to investigate how the FS-FBI scanning parameters affect the flow sensitivity and impact the depiction of pedal arteries. The study included 46 young healthy volunteers examined by FS-FBI using 1.5T MRI scanner. Additional FS-FBI examination with different flip angles (FA) of the radiofrequency refocusing pulse and echo time (TE) was performed on 36 volunteers. Two radiologists separately analyzed and graded the venous contamination, image quality, displaying rate, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) values of foot arteries. Multi-sample Friedman test and paired two-sided Student’s t test were used for statistical analysis (P < 0.05). Average image quality and venous contamination score of all arteries was good. The demonstration rate of distal anterior and posterior tibial artery, and lateral plantar artery was 100%. Dorsalis pedis artery, first dorsal metatarsal artery, medial plantar artery, and plantar arch were demonstrated at a rate above 90%. The demonstration rate of medial tarsal artery was 73.9%, whereas arcuate artery was detected with a rate of only 5.4%. Significant differences in image quality, SNR, and CNR of distal arterial area were observed between different FA and TE. Non-contrast-enhanced MR angiography of foot using FS-FBI enables clear separation of veins from arteries, and yields reliable depiction of the foot arterial tree in healthy volunteers. Distal arterial branches of foot can be better depicted by appropriate adjustment of the flow-sensitivity parameters.