Optimization of Reformatting Angle Using Orbitomeatal Base Line in Dopamine Transporter Scintigraphy

Recently, dopamine transporter (DaT) scintigraphy, which contributes to the early diagnosis of Parkinson's disease and Lewy body dementia, has been widely spread. It has been revealed that analytical results can be affected by the image-reformatting angle, and a horizontal section is recommended for the anterior commissure-posterior commissure (AC-PC) line according to the clinical guidelines for ioflupane. However, it is difficult to identify AC-PC line visually, as there is no remarkable accumulation in the cerebral parenchyma in DaT scintigraphy with poor contrast resolution. The objective of this study was to establish and optimize an adjustment method for the image-reformatting angle by using orbitomeatal base line (OM line). Evaluations were made on items such as comparison of image reformatting angles by an analyst, comparison of measurement angles of OM line, the angle formed by the intersection of OM line and AC-PC line, and the change in specific biding ratio (SBR) according to the difference in the image-reformatting angle. Consequently, the difference in analytical results among technicians became smaller, and consistent results were obtained by adjusting the image-reformatting angle.