Sacro-iliac joint scanning with technetium-99 diphosphonate

Area of Science:

• Nuclear Medicine
• Rheumatology
• Radiology

Background:

• Radio-isotope bone scanning offers quantitative assessment of joint inflammation.
• Previous studies highlight its utility in early sacro-iliitis detection.
• Quantitative sacro-iliac (SI) joint scanning with 99TcMDP is explored for evaluating SI disease.

Purpose of the Study:

• To evaluate sacro-iliac disease using quantitative SI joint scans.
• To assess the diagnostic utility of 99TcMDP scans in various low back pain patient groups.

Main Methods:

• Quantitative SI joint scans performed using 99TcMDP.
• Patient groups included controls, ankylosing spondylitis, mechanical low back pain, and seronegative arthritis.
• Radio-isotope index was calculated and compared across groups.

Main Results:

• Elevated 99TcMDP uptake (index > 1.5) observed in active ankylosing spondylitis.
• Some seronegative arthritis patients (HL-A B27 positive) and mechanical low back pain patients showed elevated uptake.
• Elevated uptake in mechanical low back pain was unassociated with B27.

Conclusions:

• Interpretation of abnormal SI joint scans requires caution due to non-specific findings.
• Quantitative bone scanning can assess inflammatory activity but needs careful correlation with clinical and other diagnostic data.
• Findings suggest potential for false positives in SI joint scans for low back pain patients without inflammatory arthritis.