Anatomical variations with joint space measurements on CT

Area of Science:

• Radiology
• Anatomy
• Medical Imaging

Background:

• Sacroiliac joint anatomical variations are not fully understood.
• Factors like age, gender, BMI, and childbirth may influence these variations.
• Understanding these variations is key for accurate interpretation of sacroiliac joint imaging.

Purpose of the Study:

• To determine the type and frequency of sacroiliac joint anatomical variations.
• To investigate the relationship between these variations and patient demographics (age, gender, BMI, childbirth).
• To assess the impact of anatomical variants on sacroiliac joint space uniformity and width.

Main Methods:

• Pelvic CT scans of 400 patients (age ≥ 15) without sacroiliac complaints were analyzed.
• Observed anatomical variants included accessory joints, iliosacral complex, bipartite iliac plate, defects, crescent plates, and ossification centers.
• Joint space width and uniformity were measured and correlated with demographic data.

Main Results:

• Common variants: accessory sacroiliac joint (17.5%), iliosacral complex (9.5%).
• Mean joint space width was 1.72 mm, narrower in older adults (1.47 mm) vs. younger adults (2.49 mm).
• Joints with variants (79.6%) showed non-uniform space and were narrower (<2 mm in 93.7%).

Conclusions:

• Sacroiliac joint anatomical variations are prevalent and independently associated with age, gender, BMI, and childbirth.
• These variations significantly impact sacroiliac joint space characteristics.
• Findings aid in the interpretation of sacroiliac computed tomography images.