Local Maximum Intensity Projection (LMIP

PURPOSE: The purpose of our study was to demonstrate a new visualization method (local maximum intensity projection; LMIP) that can clearly depict densitometric as well as geometric information in vascular visualization from 3D data such as obtained from MR and CT angiography. METHOD: LMIP is an extended version of maximum intensity projection (MIP). However, LMIP differs from MIP in that the latter method selects the maximum value along an optical ray, whereas LMIP selects the first local maximum value encountered that is larger than a preselected threshold value along an optical ray from a viewpoint in the viewing direction. RESULTS AND CONCLUSION: Examples are presented in which LMIP is used to visualize renal vessels from CT angiography data and cerebral vessels in the vicinity of an aneurysm from phase-contrast MR angiography data. We demonstrate that LMIP can clearly depict geometric information, as shaded surface display does, and densitometric information, as is done by volume rendering, in a straightforward and objective manner.