Subtractive non‐contrast‐enhanced MRI of lower limb veins using multiple flow‐dependent preparation strategies

Abstract

Purpose To evaluate the performance of acceleration‐dependent vascular anatomy for non‐contrast‐enhanced MR venography (ADVANCE‐MRV) in femoral veins and to investigate whether venous signal uniformity can be improved by applying multiple acquisitions with different flow suppressions or multiple flow suppressions in 1 acquisition. Methods The ADVANCE‐MRV method uses flow‐sensitized modules to acquire a dark‐artery image set and a dark‐artery vein set, which are subsequently subtracted. Ten healthy volunteers were imaged using the ADVANCE‐MRV sequence with improved venous suppression uniformity in the dark‐artery vein images achieved by applying multiple flow suppressions in the same acquisition or by combining multiple images acquired with different flow suppressions. The performance of the improved technique was also evaluated in 13 patients with lower‐limb deep venous thrombosis. Results Multiple‐preparation and multiple‐acquisition approaches all improved venous signal uniformity and reduced the signal void artifacts observed in the original ADVANCE‐MRV images. The multiple‐acquisition approaches achieved excellent blood signal uniformity and intensity, albeit at the cost of an increase in the total acquisition time. The double‐preparation approach demonstrated good performance in all measurements, providing a good compromise between signal uniformity and acquisition time. The blood signal spatial variation and its variation using different gradient amplitudes were reduced by 20% and 29%. All patient images showed uniform and bright venous signal in nonoccluded sections of vein. Conclusion The enhanced ADVANCE‐MRV methods substantially improved signal uniformity in healthy volunteers and patients with known deep venous thrombosis. The double‐preparation approach gave good‐quality femoral vein images, providing improved venous signal uniformity without increasing acquisition time in comparison to the original sequence.

Highly accelerated subtractive femoral non‐contrast‐enhanced MRA using compressed sensing with k‐space subtraction, phase and intensity correction

“…Subtractive NCE‐MRA is a class of techniques that displays vasculature by subtracting dark‐blood (DB) images from bright‐blood (BB) images. Typical subtractive NCE‐MRA techniques include cardiac‐gated 3D fast spin echo (FSE) (also called fresh‐blood imaging), 4,5 flow‐sensitive dephasing, 6‐9 and arterial spin labeling 10,11 …”

“…2,3 Subtractive NCE-MRA is a class of techniques that displays vasculature by subtracting dark-blood (DB) images from bright-blood (BB) images. Typical subtractive NCE-MRA techniques include cardiac-gated 3D fast spin echo (FSE) (also called fresh-blood imaging), 4,5 flow-sensitive dephasing, [6][7][8][9] and arterial spin labeling. 10,11 Most NCE-MRA methods have a much longer acquisition time than CE-MRA, which not only limits the clinical acceptance of these techniques, but also renders them sensitive to artifacts from patient motion.…”

Subtractive NCE‐MRA: Improved background suppression using robust regression‐based weighted subtraction

“…6,7 Subtractive NCE-MRA is a class of techniques that acquires two image sets (dark blood images [DBIs] and bright blood images [BBIs]) with different vascular signal intensity (SI), which are later subtracted to generate angiograms. Typical subtractive NCE-MRA techniques include flow-sensitive dephasing (FSD) [8][9][10][11][12] and fresh blood imaging (FBI). 13,14 FSD dephases moving blood spins by applying specially designed flow-sensitive preparation schemes.…”