骨延長骨癒合組織のデジタルレントゲン写真における定量的評価：画像解析技術を用いたパイロットスタディ

Assessment of distraction osteogenesis (D.O.) regenerates has traditionally relied on qualitative assessment on plain radiographs. The commonly employed methods are qualitative and are prone to inter-observer bias. Quantitative methods like the pixel density ratio have been described, but these have certain limitations. This study aimed to describe a novel technique to quantify regenerates from plain digital radiographs and compare it with the conventional Bone Mineral Density.

This was a prospective study. Eleven subjects underwent distraction osteogenesis; each patient was followed up monthly with digital radiographs and regenerate bone mineral density (BMD ratio) assessment by DEXA scan monthly for a minimum of 6 months. Quantitative analysis was performed by a novel technique using the ImageJ software, and the Area Fraction (AF) & Fractal Dimension (FD) of the regenerates were determined and compared with the BMD ratio.

AF increased steadily and FD decreased steadily as the regenerate matured. A weak negative correlation was found between the BMD ratio and FD (AP view: r = -0.28, p = 0.1 and lateral view: r = -0.16, p = 0.36). A moderate correlation was found between BMD ratio and AF (AP view: r = 0.46, p = 0.005 and lateral view: r = 0.34, p = 0.004). There was a significant difference in AF and FD values in the initial and final regenerates.

Our novel quantitative image-based analysis technique using AF and FD has the potential to efficiently quantify and monitor distraction osteogenesis regenerates. However, these results must be validated in larger patient cohorts before this technique can be used in routine clinical practice.