A post-processing protocol for three-dimensional visualization of the inner ear using the volume-rendering technique based on a standard magnetic resonance imaging protocol

A superior diagnostic quality compared to other post-processing (PP) techni ques for three-dimensional (3D) inner ear imaging has been attributed to vo lume rendering (VR). We defined and assessed a VR protocol for 3D visualiza tion of the inner ear in a routine imaging setting. Following definition of a VR protocol by using low cr threshold values, surface shading, perspecti ve views and related parameters. standardized 3D views of the inner ear. we re generated and evaluated in 32 patients suffering from sensorineural or c ombined hearing loss. Comprehensive inner ear visualization was achieved in 28 patients by means of two 3D shaded-surface views. Incomplete data acqui sition (1/32), motion and pulsation artefacts (2/32) and interposed fluid-r etaining mastoid cells (1/32) were responsible for non-diagnostic image qua lity in 4/32 patients. In 5/32 patients modifications of the PP protocol in volving the threshold value and depth-cueing parameters helped to establish diagnostic image quality. Mean post-processing time amounted to 5.8 min pe r site. 3D imaging with the VR technique is suitable for routine inner ear assessment if direct VR, predefined PP protocols and standardized labyrinth ine views are used.