The identification of spinal pathology in chronic low back pain using single photon emission computed tomography.

Bone scintigraphy with single photon emission computed tomography (SPECT) offers improved lesion detection and localization when compared to conventional planar imaging. The SPECT findings were investigated in 80 consecutive patients (aged 18-70 years, median 44) referred to a rheumatology outpatient clinic with low back pain persisting for more than 3 months. Lesions of the lumbar spine were demonstrated in 60% of patients using SPECT but in only 35% with planar imaging. Fifty-one per cent of all lesions were only detected by SPECT, and lesions visualized on SPECT could be precisely localized to the vertebral body, or different parts of the posterior elements. Fifty per cent of lesions involved the facetal joints of which almost 60% were identified on SPECT alone. X-rays of the lumbar spine, with posterior oblique views, failed to demonstrate abnormalities corresponding to almost all SPECT posterior element lesions although it identified abnormalities corresponding to over 60% of anterior SPECT lesions. Computed tomography (CT) was performed in 30 patients with a SPECT lesion and sites of facetal joint activity corresponded to facetal osteoarthritis in 82%. It is concluded that bone scintigraphy with SPECT in patients with chronic low back pain demonstrates many lesions not seen with either X-ray or conventional planar imaging. In addition anatomical localization is greatly enhanced with bone SPECT. The technique offers improved diagnosis in a group of patients often difficult to evaluate, and in particular a means of detecting apophyseal joint pathology which may be responsive to treatment.