コンピュータを活用した頚椎後縦靱帯骨化巣計測法の計測者内および計測者間信頼性の検証

A Novel Computer-Assisted Measurement of the Size of Ossification in Patients with Ossification of the Posterior Longitudinal Ligament in the Cervical Spine. Development and Reliability

　われわれはコンピュータ画像処理技術を活用し，手作業の一部を自動化した計測システム「後縦靱帯骨化症（OPLL）骨化巣画像計測ソフトウェア」を開発し，実際の計測における計測者間ならびに計測者内での信頼性に関する検証を行った．その結果，計測者間での長軸方向の長さの相関係数は0.927，95％信頼区間0.883～0.955，腹背方向の幅の相関係数は0.964，95％信頼区間は0.946～0.976であり，同一計測者内の信頼性でも，長軸方向の長さは0.943～0.985，腹背方向の幅は0.957～0.991と極めて高い一致性の相関を認めた．以上より，本法は高い精度を持つ有用な頚椎OPLL骨化巣計測法であることが示された．

　We have developed a novel system for the computer-assisted measurement to automate the conventional and manual measurement of the size of ossification in patients with ossification of the posterior longitudinal ligament in the cervical spine；and evaluated its intra and interobserver reliabilities. Eight orthopaedic surgeons measured the sizes of the ossification on nine lateral cervical spine X-ray films using the novel computer-assisted system. Data for length and thickness obtained from observers underwent statistical analysis by calculating the interclass correlation coefficient with 95％ confidence between the two measurements by the same observer to determine intraobserver reliability. The interclass correlation coefficients were 0.927 and 0.964 with a 95％ coefficient intervals of 0.883～0.995 and 0.946～0.976 for length and thickness. The interclass correlation coefficients were 0.943～0.985 for length and 0.957～0.991 for thickness. These results indicate excellent intra and interobsever reliabilities of this novel measurement.