Parkinson病型進行性核上性麻痺とParkinson病における核医学画像の比較

Comparison of nuclear medicine images between progressive supranuclear palsy-parkinsonism and Parkinson’s disease

Parkinson病（Parkinson disease：PD）はα-synuclein蛋白蓄積によるLewy小体形成により中脳黒質を中心とした神経変性を呈する疾患で，臨床症状として運動緩慢や筋強剛，安静時振戦をはじめとした左右差を伴うparkinsonismを呈し，進行期には姿勢保持障害が出現する^1）。一方で，進行性核上性麻痺（progressive supranuclear palsy：PSP）は異常リン酸化tau蛋白が脳幹や基底核を中心に蓄積し，Richardson症候群（以下，PSP-RS）と呼ばれる典型例では初期から姿勢保持障害の強いparkinsonismや眼球上下転障害など特徴的な症状を呈する^2）。しかし，Parkinson病型PSP（以下，PSP-P）では運動症状がPDに類似しており，両者の鑑別が困難な場合が多い^3）。PSP-Pは臨床経過とともにPSP-RSに類似した症候に進展しPDと比較すると予後は不良であり^2），これらの鑑別が臨床上の課題である。今回我々はPSP-PおよびPD症例における核医学画像の鑑別に有用な所見の検討を行った。

We retrospectively collected the image data of patients admitted to our hospital from January 2017 to June 2019 and consistent with Movement Disorder Society diagnostic criteria of progressive supranuclear palsy-parkinsonism（PSP-P）or Parkinson’s disease（PD）. All included patients underwent both ¹²³I-MIBG myocardial scintigraphy and ¹²³I-FP-CIT SPECT. Patients whose images were taken more than a year before the hospitalization were excluded. These images were statistically compared between the two groups. We also performed receiver operating characteristic curve analysis. Image data of 11 PSP-P patients and 25 PD patients were collected. Significant differences were found in the early and delayed heart-to-mediastinum ratio and washout ratio of ¹²³I-MIBG myocardial scintigraphy. The areas under the curve were 0.9236, 0.9600, and 0.8764, respectively. ¹²³I-MIBG myocardial scintigraphy possibly differentiates PSP-P from PD.