SU‐GG‐I‐140: Maximum Intensity Projection (MIP) Imaging Using Multi‐Slice Cine MRI

Abstract

Purpose: To propose a novel method of acquiring Maximum Intensity Projection (MIP) images using multi‐slice cine MRI, termed as MRI‐MIP, and to evaluate its feasibility in quantifying motion magnitude. Materials and Methods: MRI‐MIP images are acquired using a modified multi‐slice cine MR sequence in which each axial slice was imaged repeatedly throughout the duration of the respiratory cycle. A maximum intensity image was then constructed for each slice using all acquired images. For this study, we used a 1.5T clinical whole body MRI scanner (Signa, GE Healthcare, WI) and a sequence of fast imaging employed steady state acquisition (FIESTA) with a six channel phased array flexible coil to acquire 15 images in 6 seconds for each slice (flip angle= 50°, matrix= 192×128, FOV= 300×300mm, slice thickness= 0.5mm, TR/TE= 3.2/1.0ms). To test feasibility, MRI‐MIP, CT‐MIP, and single slice sagittal cine‐MR images were acquired of a 66 cm3 polygonal phantom placed on an MR compatible motion platform with Superior‐Inferior motion consisting of 2 analytical (peak‐to‐peak amplitude = 2.8cm, period = 5s) and 3 patient motion trajectories from Varian RPM. We also acquired MRI‐MIP and single slice sagittal cine‐MRI images for 3 healthy volunteers and compared the areas of interest. Results: Phantom volume from MRI‐MIP was well correlated with CT‐MIP, with the mean (± standard deviation) difference from CT MIP being 0.1%±2.9% and a max difference of −4.2%. For the analytical trajectories, area from MRI‐MIP matched cine‐MRI to within ±0.3%. For patient motion trajectories, the difference in phantom area between MRI‐MIP and cine‐MRI was −10.4%, −7.4%, and −6.6%. For patient images, the difference in contoured areas was −5.5%, 2.3%, and 4.8%. Conclusion: Preliminary results on phantom and healthy volunteers suggest using multi‐slice cine MRI to generate MIP is feasible. Motion information obtained from this technique is comparable to that from 4DCT‐MIP.