Transparent color-coded three-dimensional diffusion-weighted magnetic resonance imaging for the numerical analysis of reversible and irreversible hyperacute ischemic stroke--case report.

Although diffusion-weighted (DW) magnetic resonance (MR) imaging can detect hyperacute ischemic parenchyma with high sensitivity, the ability of DW images to reveal subtle change in abnormal diffusion may be limited by the conventional visual evaluation. To overcome the limitation, we have developed a method of transparent color-coded three-dimensional (3D) DW MR imaging for the computer-aided numerical analysis of hyperacute ischemic stroke. The 3D images were reconstructed from volume data of source DW images by using a parallel volume-rendering algorithm with transluminal imaging technique. By selecting a threshold range from a signal intensity opacity chart of volume-rendering data set, several high signal intensity areas were depicted and assigned to different colors, transparently through contours of the brain. This imaging was applied in a case of a recanalized middle cerebral artery (M2) occlusion with partially reversible ischemic parenchyma accompanied by partial recovery from ischemic neurological deficit. Complex and dynamic change in hyperacute ischemic parenchyma, with regression of subtle high signal intensity areas and progression of ischemic parenchyma, was depicted three-dimensionally. Transparent color-coded 3D DW MR imaging may provide computer-aided numerical analysis of hyperacute ischemic stroke appearing as a high signal intensity area on the source DW images.