Peripheral moving-table contrast-enhanced magnetic resonance angiography (CE-MRA) using a prototype 18-channel peripheral vascular coil and scanning parameters optimized to the patient's individual hemodynamics.
OBJECTIVE
To demonstrate that with a priori determination of individual patient hemodynamics, peripheral contrast-enhanced magnetic resonance angiography (pCE-MRA) can be customized to maximize signal-to noise ratio (SNR) and avoid venous enhancement.


METHODS
Using a 1.5T MRI scanner and prototype 18-channel peripheral vascular (PV) coil designed for highly accelerated parallel imaging, geometry (g)-factor maps were determined. SNR-maximized protocols considering the two-dimensional sensitivity encoding (2D SENSE) factor, TE, TR, bandwidth (BW), and flip angle (FA) were precalculated and stored. For each exam, a small aortic timing bolus was performed, followed by dynamic three-dimensional (3D)-MRA of the calf. Using this information, the aorta to pedal artery and calf arteriovenous transit times were measured. This enabled estimation of the maximum upper and middle station acquisition duration to allow lower station acquisition to begin prior to venous arrival. The appropriately succinct SNR-optimized protocol for each station was selected and moving-table pCE-MRA was performed using thigh venous compression and high-relaxivity contrast material.


RESULTS
The protocol was successfully applied in 15 patients and all imaging demonstrated good SNR without diagnosis-hindering venous enhancement.


CONCLUSIONS
By knowing each patient's venous enhancement kinetics, scan parameters can be optimized to utilize maximum possible acquisition time. Some time is added for the timing scans, but in return time-resolved calf CE-MRA, maximized SNR, and decreased risk of venous enhancement are gained.
Potthast
Silke
S
Department of Radiology, University of Washington, Seattle, Washington, USA.
Wilson
Gregory J
GJ
Wang
Maisie S
MS
Maki
Jeffrey H
JH
D001158:Arteries / Q000033:anatomy & histology* / Q000502:physiology; D001783:Blood Flow Velocity / Q000502:physiology; D003287:Contrast Media; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation*; D018810:Magnetic Resonance Angiography / Q000295:instrumentation* / Q000379:methods; D008280:Magnetics / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D009038:Motion; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012149:Restraint, Physical / Q000295:instrumentation*; D012680:Sensitivity and Specificity; D014159:Transducers
D003287:Contrast Media