document: Three-dimensional spiral MR imaging : application to renal multiphase contrast-enhanced angiography A fast MR pulse sequence with spiral in-plane readout and conventional 3D partition encoding was developed for multiphase contrast-enhanced magnetic resonance angiography -LRB- CE-MRA -RRB- of the renal vasculature . Compared to a standard multiphase 3D CE-MRA with FLASH readout , an isotropic in-plane spatial resolution of 1.4 * 1.4 mm/sup 2 / over 2.0 * 1.4 mm/sup 2 / could be achieved with a temporal resolution of 6 sec . The theoretical gain of spatial resolution by using the spiral pulse sequence and the performance in the presence of turbulent flow was evaluated in phantom measurements . Multiphase 3D CE-MRA of the renal arteries was performed in five healthy volunteers using both techniques . A deblurring technique was used to correct the spiral raw data . Thereby , the off-resonance frequencies were determined by minimizing the imaginary part of the data in image space . The chosen correction algorithm was able to reduce image blurring substantially in all MRA phases . The image quality of the spiral CE-MRA pulse sequence was comparable to that of the FLASH CE-MRA with increased spatial resolution and a 25 % reduced contrast-to-noise ratio . Additionally , artifacts specific to spiral MRI could be observed which had no impact on the assessment of the renal arteries
doc_bio_tags: O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O
extractive_keyphrases: deblurring 3d partition encoding renal vasculature image quality spatial resolution
abstractive_keyphrases: 3d spiral mri renal multiphase contrast-enhanced angiography flow artifacts fast pulse sequence spiral in-plane readout off-resonance frequencies reduced contrast-to-noise ratio image reconstruction flash sequence