Radiological Symmetry of Brain and Head Images: Comparison and Applications

Abstract

Most existing image-based approaches neglect the difference in radiological symmetry between the human brain and head. Thus, it is important to analyze and quantify the spatial relationship between the brain symmetry plane (BSP) and the head symmetry plane (HSP) on radiological images. The HSP and BSP were calculated through maximizing local symmetry within the head or cerebrum followed by outlier removal. The HSPs and BSPs for 145 diversified MRI datasets (80 normal, 23 pathological, and 42 synthesized) were extracted and compared. The average angular and distance deviations between the HSP and BSP were 0.49° and 1.65 mm, respectively. These deviations are dependent upon ethnicity and gender, being: (1) (0.56°, 1.85 mm) and (0.42°, 0.91 mm) for Caucasians and Asians, respectively; and (2) (0.33°, 1.17 mm) and (0.51°, 1.58 mm) for males and females, respectively. The HSP is generally different from the BSP on MR images. Statistically, they can be used interchangeably if accuracy of (0.49°, 1.65 mm) is acceptable. The BSP is preferred for a high accuracy Talairach transformation and localization of the anterior and posterior commissures. Either BSP or HSP can be used for medium accuracy Talairach transform. The HSP is preferred for detecting intracranial pathology.