Jg. Hanly et al., SINGLE-PHOTON EMISSION COMPUTED-TOMOGRAPHY IN THE DIAGNOSIS OF INFLAMMATORY SPONDYLOARTHROPATHIES, Journal of rheumatology, 20(12), 1993, pp. 2062-2068
Objective. The role of bone scintigraphy in the evaluation of patients
with inflammatory spondyloarthropathy is controversial and previous s
tudies have reported a lack of sensitivity and specificity. The aim of
our study was to determine whether single photon emission computed to
mography (SPECT) scanning would enhance the clinical utility of bone s
cintigraphy in the detection of inflammatory axial disease, in particu
lar sacroiliitis. Methods. Twenty patients with definite sacroiliitis
(New York criteria >1) on plain film radiographs and 20 age matched co
ntrols were studied. Bone scintigraphy and SPECT scanning were carried
out 2 h after an intravenous injection of Tc-99m imidodiphosphonate (
IDP). A quantitative and qualitative assessment of radiopharmaceutical
uptake in the sacroiliac (SI) joints was derived from planar films an
d a qualitative analysis of uptake in the SI joints was derived from S
PECT scans. All films were read without knowledge of patient identific
ation. Results. Quantitative analysis of planar films did not identify
any difference between study and control groups (p>0.05). Qualitative
assessment of planar films identified features of!sacroiliitis more f
requently in patients than in controls (p<0.05) with a sensitivity of
25% and a specificity of 95%. SPECT scanning also revealed enhanced ra
diopharmaceutical uptake in the SI joints more frequently in patients
than in controls (p<0.001) with a sensitivity of 85% and a specificity
of 90%. Increased uptake in the lumbar facet joints and costovertebra
l joints was identified in 3 patients. Similar abnormalities were not
detected in the control group. Conclusion. Our results indicate that S
PECT scanning is both sensitive and specific for the detection of esta
blished sacroiliitis and may also identify inflammatory disease at oth
er sites in the spine.