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 cm3polygonal 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.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging