Zero-filling Interpolation Processing Technique Can Efficiently Suppress Segmental Stenosis Artifact On Small Artery Of Anatomical Phantoms

Objective: As a noninvasive method, conventional contrast-enhanced MR angiography has been widely applied in clinical practice. Because of lower spatial resolution and serious artifact, however, the application of conventional CE-MRA has been limited. The purpose of this study was to evaluate the zero-filling interpolation processing (ZIP) technique for contrast-enhanced MR angiography (CE-MRA).Methods and Materials: Phantoms of arteries were made with different lumen diameter. Gadolinium-enhanced three-dimensional MR angiography was performed on a GE 1.5T scanner. The parameters of FSPGR pulse sequence were: flip angle 30°, TR 6ms, TE 1.4ms, bandwidth 31.25kHz, slice thickness 1.2mm, matrix 256×256. The sequence parameters were kept constant for the studies, whereas four selections were chosen: Ⅰ . with ZIP 1024 and ZIP×4 techniques; Ⅱ. only with ZIP 1024 technique; Ⅲ. only with ZIP×4 technique; Ⅳ. without ZIP technique. For image quality evaluation, MR maximum intensity projection (MIP) images were created. Signal-to-noise ratio(SNR) was measured on MIP images. Vessel edge was determined using full width at half maximum (FWHM) for lumen diameter calculation. After MR angiography scanning, digital subtraction angiography was performed on a GE Advantx 1000mA X-ray machine 0 CE-MRA images were compared with DSA images by four radiologists oResults: The FWHM results of lumen measurements for all ZIP techniques were more accurate than conventional technique in all nine phantoms according to the actual lumen diameter, no matter which size the artery was. The vessel edge with ZIP 1024 technique was more distinct than conventional technique, especially the sequence with both ZIP 1024 and ZIPX4 techniques, but the difference between ZIPX4 sequences and conventional sequence was not obvious. Segmental stenosis artifacts on little phantoms of artery were seen in the images of high-spatial-resolution sequences only with ZIP 1024 technique and the conventional sequence, and there is no difference between them. These segmental stenosis artifacts on little phantoms of artery were efficiently suppressed with ZIPX4 technique, and no segmental stenosis artifacts was found on the little phantoms when the sequence with both ZIP 1024 and ZIPX4 technique. However, the highest average SNR (33.7±3.63) was obtained with conventional technique, the difference between ZIP 1024 sequences and conventional sequence was statisticallysignificant (PO.01), but there was no statistical significance (P>0.05) between ZIPX4 sequences and conventional sequence. The CE-MRA with ZIP 1024 and ZIP X 4 techniques were as good as DSA.Conclusion: ZIP technique is excellent for CE-MRA to obtain high quality MR angiography. It not only can improve the spatial resolution and the distinctness of the vessel edge on CE-MRA, but also can efficiently suppress segmental stenosis artifact on small artery of phantoms. CE-MRA with ZIP 1024 and ZIPX4 techniques both can acquire best images.