Chalk up another study demonstrating the superiority of magnetic resonance imaging (MRI) in visualizing changes in the sacroiliac joints, one of the criteria used to diagnose spondylitis. This study’s researchers sought to compare a new MRI scoring system of the sacroiliac joints in early spondylitis.

The sacroiliac joints are the firm, small joints that lie at the junction of the spine and the pelvis. They are centrally involved in spondylitis, most clearly in ankylosing spondylitis, in which most patients are affected early in the disease. Sacroiliac changes do not always show up with other diagnostic tools (e.g. CAT scan, x-rays).

Magnetic resonance imaging (MRI) uses radio frequency waves and a strong magnetic field rather than x-rays to provide remarkably clear and detailed pictures of internal organs and tissues. Because MRI can give such clear pictures of soft-tissue structures near and around bones, it is the most sensitive exam for spinal and joint problems.

Participants
Forty-one patients (24 males, 17 females) with an average age of 26-years-old and an average duration of inflammatory low back pain of 19 months took part. They all fulfilled the European Spondyloarthropathy Study Group (ESSG) criteria for spondylitis, which includes the following: inflammatory spinal pain or synovitis and any one of the following -- positive family history, psoriasis, inflammatory bowel disease, alternative buttock pain, enthesopathy.

Results

• 95% of the participants had inflammation and/or destructive bone change of the sacroiliac joints at MRI
  
• No correlation was found between MRI pathology and clinical findings
  
• MRI demonstrated significantly greater severity of both inflammation and destruction of the sacroiliac joints in HLA-B27 positive patients than in the HLA-B27 negative patients.

The researchers conclude that in people with early disease, MRI was able to detect inflammatory and destructive changes of the sacroiliac joints in spondylitis, but the changes were not associated to clinical findings (meaning that a doctor cannot see the findings upon clinical evaluation). They point out that the results suggest a role of MRI in the detection of early-stage sacroiliitis.

Source -- Magnetic resonance imaging of sacroiliitis in early seronegative spondyloarthropathy. Abnormalities correlated to clinical and laboratory findings. Rheumatology (Oxford). 2003 Sep 16. Puhakka KB, Jurik AG, Schiottz-Christensen B, Hansen GV, Egund N, Christiansen JV, Stengaard-Pedersen K.