Complex motion tomography of the sacroiliac joint. An anatomical and roentgenological study.

To find a better method for diagnosing sacroiliac (SI) joint disease, an anatomical approach was combined with conventional roentgenology, complex motion tomography and computed tomography. Complex motion tomography is suggested as the method of choice in the investigation of the SI-joint. Because of its complex (sinusoidal) form, the dorsal portion of the joint has to be tomographed in frontal projection and the middle and ventral portions in oblique projection. In 56 patients, referred for probable ankylosing spondylitis, 72 SI joints were investigated. Based on plain radiography six and on frontal tomography five SI joints were diagnosed as normal. However, based on oblique tomography 31 joints were diagnosed as normal.