Thick-section, single breath-hold magnetic resonance pulmonary angiography.
OBJECTIVE
Approaches to performing magnetic resonance angiography (MRA) of the pulmonary vasculature are described using very fast (repetition time [TR] less than 13 mseconds) radiofrequency (rf)-spoiled, gradient-recalled pulse sequences and the standard quadrature body imaging coil of a commercial 1.5-T MR imaging system.


RESULTS
Signal-to-noise (SNR) is improved by signal averaging (Nex greater than or equal to 4) in a two-dimensional, single thick-section approach and by volume acquisition (Nex = 1) in a three-dimensional approach. Blood signal loss is minimized by using short, asymmetric echoes (echo time [TE] less than or equal to 2.7 mseconds). Respiratory motion is eliminated by keeping the scan time short enough (approximately 15 seconds) for image acquisition within a single breath-hold. Cardiac motion artifacts are reduced with section orientations that avoid intersecting the heart and/or use of small flip angle (alpha less than or equal to 25 degrees).


CONCLUSIONS
Images of healthy volunteers showed that while single thick sections have superior SNR, the three-dimensional approach appears to produce better visualization of the peripheral vascular segments and offers improved ability to process the images to remove overlapping structures.
MacFall
J R
JR
Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710.
Sostman
H D
HD
Foo
T K
TK
D000328:Adult; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011651:Pulmonary Artery / Q000033:anatomy & histology*; D011667:Pulmonary Veins / Q000033:anatomy & histology*; D012016:Reference Values