Subchondral bone strength of the sacroiliac joint-a combined approach using computed tomography osteoabsorptiometry (CT-OAM) imaging and biomechanical validation

Computed tomography osteoabsorptiometry-based investigation on subchondral bone plate alterations in sacroiliac joint dysfunction

“…Previous studies showed complete SIJ non-conformity and denser mineralization patterns on the iliac side 12 . High mineralization zones (≥ 700 HU) were found around the borders, apex and the corners of the auricular surfaces 12 , 20 . As asymmetrical gait and abnormal biomechanics are typically observed in SIJD patients, likely as a compensatory mechanism 21 , changes in bone mineralization patterns may reflect on the auricular surfaces caused by the abnormal loads instigated by SIJD.…”

“…CT-OAM was evaluated using a specific image analysis program (Analyze, v7.4, Biomedical Imaging Resources, Mayo Foundation, Rochester, NY, USA). According to a previous study 12 , the sacral and iliac sides of each SIJ were manually segmented within the CT datasets before the data were false color-coded and superimposed on the 3-dimensionally reconstructed ilia and sacra for anatomical localization of the mineral bone density creating a bone mineral density ‘densitogram’. The maximum intensity projection revealed the HU of each pixel to a depth of 3 mm 14 and threshold values were chosen according to previous studies to be ≤ 200 to ≥ 1200 HU 12 , 13 .…”

“…The subchondral bone (SCB) is known to adjust to long-term repetitive load transfer through an increase in bone mineralization which can be observed in CT-osteoabsorptiometry (CT-OAM) densitograms 11 – 14 . Given the effects of Wolff’s law, resulting in bone aligning to mechanical loading, the SCB adjusts to the load transfer though an increase in bone mineralization seen in CT-OAM 11 , 12 , 15 . CT-OAM provides colour-mapped densitograms using Hounsfield units (HU) to illustrate the bone mineralization of an articular surface 12 – 14 , 16 – 19 .…”

“…Given the effects of Wolff’s law, resulting in bone aligning to mechanical loading, the SCB adjusts to the load transfer though an increase in bone mineralization seen in CT-OAM 11 , 12 , 15 . CT-OAM provides colour-mapped densitograms using Hounsfield units (HU) to illustrate the bone mineralization of an articular surface 12 – 14 , 16 – 19 . Previous studies showed complete SIJ non-conformity and denser mineralization patterns on the iliac side 12 .…”

“…CT-OAM provides colour-mapped densitograms using Hounsfield units (HU) to illustrate the bone mineralization of an articular surface 12 – 14 , 16 – 19 . Previous studies showed complete SIJ non-conformity and denser mineralization patterns on the iliac side 12 . High mineralization zones (≥ 700 HU) were found around the borders, apex and the corners of the auricular surfaces 12 , 20 .…”