Maximum intensity projection (MIP) imaging using slice‐stacking MRIa)

Purpose:To evaluate the feasibility of acquiring maximum intensity projection (MIP) images using a novel slice‐stacking MRI (SS‐MRI) technique.Methods:The proposed technique employed a steady state acquisition sequence to image multiple axial slices. At each axial slice, the scan is repeated throughout one respiratory cycle. Four objects (small, medium, and large triangles, and a cylinder) moving with a patient breathing trajectory were imaged repeatedly for six times using the slice‐stacking MRI and 4D‐CT. and were reconstructed. The internal target volume (ITV) was segmented for each object on the six scans and compared between and . The medium triangle was also imaged with various motion patterns using slice‐stacking MRI, 4D‐CT, and sagittal cine‐MRI. The corresponding MIP images were reconstructed and volume/area measurements were performed and compared between different imaging methods. Three healthy volunteers underwent the slice‐stacking MRI and sagittal cine‐MRI scans. A region of interest (ROI) was selected and contoured for each subject in both and . The area of the selected ROI was computed and compared.Results:Volume comparison between and showed statistically insignificant ( in all cases) difference in the mean ITVs for all four objects. For the study of the medium triangle with multiple motion patterns, there was a good agreement in the measured ITVs between and (, correlation ), with a mean difference of . The area measurements between and also showed good agreement (, correlation ), with a mean difference of . For the healthy volunteer study, the average difference in the area of selected ROI was between and .Conclusions:These preliminary results showed good agreement in volume/area measurements between the slice‐stacking MRI technique and 4D‐CT/cine‐MRI, indicating that it is feasible to use this technique for MIP imaging.