New research warns patients under 40 about accuracy of CT Scans for low back pain.

Doctors at Tel Aviv University say

• A total of 484 lumbar spine CT examinations (272 men, 212 women; average age, 31 years; age range, 18-40 years) of patients with low back pain in which the entire sacroiliac joint or SI joint (SIJ) were visualized were retrospectively reviewed.
• SIJs were scored (consensus) by two senior radiologists (study reading) for the presence of post-inflammatory structural sacroiliac joint findings or other sacroiliac joint alterations.
• The original reports were compared to the study reading. Fifty CT examinations were re-evaluated for reliability assessment
• Results
  • A total of 150 (31%) abnormal sacroiliac joint examinations were registered
  • suspected sacroiliitis = 50 (10.2%);
  • definite sacroiliitis = 16 (3.3%);
  • osteitis-condensans-ilii (soft-tissue hardening) = 38 (7.8%);
  • diffuse idiopathic skeletal hyperostosis = 24 (5%);
  • degenerative changes = 22 (4.5%);
  • accessory sacroiliac joint = 22 (4.5%);
  • and tumor = 1.
• The sacroiliac joint were referenced 39 times (8.0%) in the original readings: pathological findings (15); and normal sacroiliac joint (24). Total diagnostic accuracy for these reports only and for the entire readings were 49% and 69%, respectively, and 13% and 1.3%, respectively, for the pathological findings.
• Conclusion Sacroiliitis and other sacroiliac joint alterations are prevalent in young individuals with low back pain, albeit, the majority of these alterations are not recognized nor reported by senior radiologists thus may delay effective treatment.

Prevalence and awareness of sacroiliac joint alterations on lumbar spine CT in low back pain patients younger than 40 years.
1 Klang E, Lidar M, Lidar Z, Aharoni D, Eshed I. Prevalence and awareness of sacroiliac joint alterations on lumbar spine CT in low back pain patients younger than 40 years. Acta Radiol. 2017 Apr;58(4):449-455. [Pubmed]