Optimizing three-dimensional gadolinium-enhanced magnetic resonance angiography. Original investigation

RATIONALE AND OBJECTIVES: This primarily theoretical work examines three-dimensional gadolinium-enhanced magnetic resonance angiography f8p4Gd-MRA) with the goal of understanding how to achieve the best possible images with respect to signal to noise ratio (SNR) and k-space induced artifacts. Patient variables, contrast injection schemes, and pulse sequence parameters are considered for this purpose. METHODS: A theoretical analysis, including computer simulation, describes how contrast material injection profiles influence 3D Gd-MRA images, both in terms of intravascular signal and resultant artifacts. Further theoretical analysis of the spoiled gradient refocused pulse sequence describes how to maximize SNR. Clinical imaging complements computer modeling. RESULTS: Equations were derived relating contrast injection parameters and pulse sequence variables to SNR and artifacts. For present imaging equipment, administering contrast material over a duration of 60% to 80% of the total imaging time and using fractional echo techniques gives the best SNR without significantly sacrificing image quality. CONCLUSIONS: Three-dimensional Gd-MRA can be tailored to a specific clinical situation and imaging system through the use of proper breath-holding, bolus timing, Gd administration, and pulse sequence design.