James D. Stensby MD, Presenter: Nothing to Disclose

Cree Michael Gaskin MD, Abstract Co-Author: Author with royalties, Oxford University Press Author with royalties, Thieme Medical Publishers, Inc

David Ansley Lawrence MD, Abstract Co-Author: Nothing to Disclose

To determine trends in incidentally detected age- and gender-associated sacroiliac fusion and chondrocalcinosis on pelvic CT. 

IRB approved. We identified CT scans of the pelvis performed 2009-2013 and selected 20 patients of each gender at the center of each decade of life (age 5, 15, 25, . . .95 years) for a total of 400 pelvic CTs. We reviewed the electronic health record of each patient and excluded those with low back or sacroiliac pain; known afflictions of the pelvis joints or systemic rheumatologic conditions; history of sacroiliitis, ankylosing spondylitis, inflammatory bowel disease, HLA B27 arthropathy, hemochromatosis, hyperparathyroidism, Wilson’s disease, or hypothyroidism. We backfilled for any excluded patients to maintain 20 subjects in each set. CTs were reviewed in consensus by 2 MSK radiologists for SI joint fusion and chondrocalcinosis of any pelvic joint. Logistic regression was used to predict the presence/absence of SI fusion and chondrocalcinosis as a function of patient age and gender. The model predictors included a classification variable to identify patient gender, and linear and non-linear restricted cubic-spline functions of patient age.  

SI fusion was associated with both patient age (P=0.003) and patient gender (P<0.001). SI joint fusion was seen more frequently in both older males and females, although at any particular age the odds of SI fusion was predicted to be 7.1 times greater (95% CI: [3.2, 15.7]) for males than females (P<0.001). The presence/absence of chondrocalcinosis was found to be associated with patient age (P=0.016) but not patient gender (P=0.929). (Fig.) (445)

Incidentally detected SI joint fusion is common in older patients, particularly in men. It is an uncommon finding in patients <45 years of age, particularly in women, and may warrant clinical evaluation. Chondrocalcinosis is more prevalent in older patients, without a gender predilection and is infrequently identified in patients younger than age 50. 

When SI joint fusion is detected in older male patients it likely reflects an age and gender related phenomenon rather than sequela of disease. For patients <45 years age, particularly women, SI joint fusion is suggestive of underlying disease process. 

Stensby, J, Gaskin, C, Lawrence, D, Arthritis or Aging? A Review of the CT Findings in the Osseous Pelvis in an Aging Population.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14008120.html