薬物関連顎骨壊死に対する定量的骨SPECT/CTの臨床現場での有用性

Usefulness of quantitative bone SPECT/CT for medication-related osteonecrosis of the jaw in clinical settings.

抄録

目的:

本研究は、薬物関連顎骨壊死（MRONJ）に対する定量的骨単一光子コンピューター断層撮影法（SPECT/CT）の検出および分類の臨床的有用性を検討するために実施された。

OBJECTIVE: This study was conducted to investigate the clinical utility of quantitative bone single-photon computed tomography-computed tomography (SPECT/CT) for detection and classification for medication-related osteonecrosis of the jaw (MRONJ).

材料と方法:

日本口腔外科学会専門医4名がAAOMS診断基準により臨床的にMRONJと診断し，骨SPECT/CTを施行した59例（69病変）を登録した。読影者1名がGI-BONEソフトウェアパッケージを用い，最大（SUVmax），ピーク（SUVpeak），平均（SUVmean）を含む標準摂取値（SUV），閾値以上の総量を表す代謝骨量（MBV），MBV×SUVmeanとして計算した総骨摂取量（TBU）を測定した．臨床病期間の定量値の比較には，一元配置反復測定分散分析とそれに続くポストホック分析を用いた。数値の再現性を確認するため、別の読影医が定量値を算出した。

MATERIALS AND METHODS: Fifty-nine patients (69 lesions) clinically diagnosed as MRONJ by four specialists of Japanese Society of Oral Surgery according to the AAOMS diagnostic criteria and who underwent bone SPECT/CT were enrolled. One reader determined standard uptake values (SUVs), including maximum (SUVmax), peak (SUVpeak), and mean (SUVmean), as well as metabolic bone volume (MBV), representing total volume above threshold, and total bone uptake (TBU), calculated as MBV × SUVmean, using the GI-BONE software package. One-way repeated-measures analysis of variance and subsequent post hoc analysis were employed to compare quantitative values between clinical stages. To check reproducibility of values, another reader calculated these quantitative values.

結果:

ステージ0（n=21）、1（n=13）、2（n=25）、3（n=10）のSUVmax平均値はそれぞれ5.82±3.20、5.46±3.79、8.16±3.93、10.57±8.43、MBVの値は9.8。MBVは9.52±6.33、11.36±7.32、12.4±8.21、17.84±16.94、TBUは40.60±46.97、53.70±77.26、62.37±42.91、102.01±74.52であった。SUVmax、SUVpeak、SUVmeanは臨床病期によって有意差があった（それぞれp=0.024, p=0.027, p=0.039）。また、ポストホック解析の結果、ステージ3のSUVmaxとSUVpeakはステージ0のそれよりも有意に高かった（それぞれ、p=0.046、0.045）。MBVとTBUはstageが上がるにつれて増加する傾向を示したが、stage間の差は有意ではなかった（それぞれp=0.15, p=0.053)。SUVmax、SUVpeak、SUVmean、MBV、TBUの平均値は、2人の読影医の間でほとんど差がなかった（それぞれ、-3.10％、-0.26％、-4.24％、0.69％、-3.42％）。SUVmax，SUVpeak，SUVmean，MBV，TBUのクラス内相関係数（ICC）はそれぞれ0.985，0.990，0.980，0.994（すべての数値でほぼ完全）であった。

RESULTS: Mean SUVmax values for stage 0 (n = 21), 1 (n = 13), 2 (n = 25), and 3 (n = 10) were 5.82 ± 3.20, 5.46 ± 3.79, 8.16 ± 3.93, and 10.57 ± 8.43, respectively, while values for MBV were 9.52 ± 6.33, 11.36 ± 7.32, 12.4 ± 8.21, and 17.84 ± 16.94, respectively, and for TBU were 40.60 ± 46.97, 53.70 ± 77.26, 62.37 ± 42.91, and 102.01 ± 74.52, respectively. There were significant differences for SUVmax, SUVpeak, and SUVmean between clinical stages (p = 0.024, p = 0.027, p = 0.039, respectively). Subsequent post hoc analysis showed that SUVmax and SUVpeak of stage 3 were significantly higher than those of stage 0 (p = 0.046, 0.045, respectively). MBV and TBU showed a tendency to increase with increased stage, though differences between stages were not significant (p = 0.15, p = 0.053, respectively). Little differences of mean SUVmax, SUVpeak, SUVmean, MBV, and TBU between two readers were observed (- 3.10%, - 0.26%, - 4.24%%, 0.69%, and - 3.42%, respectively). The intraclass correlation coefficients (ICCs) of SUVmax, SUVpeak, SUVmean, MBV, and TBU were 0.985, 0.990, 0.980, 0.994, and 0.994, respectively (almost perfect for all values).

結論:

定量的な骨SPECT/CTの結果から得られるSUVmaxとSUVpeakは、客観的で信頼性の高い指標として、MRONJ患者の病期診断のみならず、早期状態の検出にも有用である。

CONCLUSION: As objective and reliable indicators, SUVmax and SUVpeak derived from quantitative bone SPECT/CT results are useful for detection of early status disease, as well as staging in MRONJ patients.