THE EFFICACY OF NON-ECHO PLANAR DWI COMBINED WITH MR CISTERNOGRAPHY IN THE DIAGNOSIS OF CHOLESTEATOMA EXTENSION

Abstract

　Diffusion-weighted imaging (DWI) provides surgeons with a superior imaging tool to more accurately diagnosis cholesteatoma which are to be treated using transcanal endoscopic ear surgery (TEES). Two different DWI techniques are currently in use: non-echo planar (non-EPI) and echo planar (EPI) DWI. In the comparison of preoperative evaluation for cholesteatoma and intraoperative findings by non-EPI DWI and EPI DWI, both positive predictive value (PPV) and negative predictive value (NPV) of non-EPI DWI were high. PPV of EPI DWI was high, however NPV of EPI DWI was low. Therefore, non-EPI DWI is more reliable in identifying cholesteatomas than EPI DWI. Non-EPI DWI can be even further enhanced by the incorporation of MR cisternography (MRC). We combined a 1-mm thin slice non-EPI DWI with MRC and performed color mapping to enhance the visualization of the cholesteatoma by this color mapped fusion imaging (CMFI). Both PPV and NPV were high in the comparison of the preoperative evaluation for cholesteatomas and intraoperative findings. We found that CMFI is a reliable tool for preoperative evaluation of the anatomical location of a cholesteatoma and to determine whether a patient is indicated for TEES to treat cholesteatomas.