OBJECTIVES To explore the role of the available midbrain-based MRI morphometric assessments in (1) differentiating among progressive supranuclear palsy (PSP) subtypes (PSP Richardson's syndrome (PSP-RS), PSP with predominant parkinsonism (PSP-P) and the other variant syndromes of PSP (vPSP)), and (2) supporting the diagnosis of PSP subtypes compared with Parkinson's disease (PD) and healthy controls (HC). METHODS Seventy-eight patients with PSP (38 PSP-RS, 21 PSP-P and 19 vPSP), 35 PD and 38 HC were included in the present analysis. Available midbrain-based MRI morphometric assessments were calculated for all participants. RESULTS Current MRI midbrain-based assessments do not display an adequate sensitivity and specificity profile in differentiating PSP subtypes. On the other hand, we confirmed MR Parkinsonism Index (MRPI) and pons area to midbrain area ratio (P/M) have adequate diagnostic value to support PSP-RS clinical diagnosis compared with both PD and HC, but low sensitivity and specificity profile in differentiating PSP-P from PD as well as from HC. The same measures show acceptable sensitivity and specificity profile in supporting clinical diagnosis of vPSP versus HC but not versus PD. Similar findings were detected for the newer MRPI and P/M versions. CONCLUSIONS Further studies are warranted to identify neuroimaging biomarkers supporting the clinical phenotypic categorisation of patients with PSP. MRPI and P/M have diagnostic value in supporting the clinical diagnosis of PSP-RS. CLASSIFICATION OF EVIDENCE This study provides class III evidence that available MRI midbrain-based assessments do not have diagnostic value in differentiating the Movement Disorder Society PSP subtypes.

中文翻译：

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进行性核上性麻痹亚型的中脑MRI评估。

目的探讨可用的基于中脑的MRI形态计量学评估在（1）区分进行性核上性麻痹（PSP）亚型（PSP理查森综合征（PSP-RS），具有主要帕金森病（PSP-P）的PSP和其他变体中的作用PSP综合征（vPSP）），以及（2）与帕金森氏病（PD）和健康对照（HC）相比，支持PSP亚型的诊断。方法本研究纳入了78例PSP患者（38例PSP-RS，21例PSP-P和19例vPSP），35例PD和38例HC。为所有参与者计算了可用的基于中脑的MRI形态计量学评估。结果当前基于MRI中脑的评估不能在区分PSP亚型中显示出足够的敏感性和特异性。另一方面，我们证实，与帕金森病和HC相比，MR帕金森病指数（MRPI）和脑桥面积与中脑面积之比（P / M）具有足够的诊断价值，可支持PSP-RS临床诊断，但在区分PSP-P和PD方面具有较低的敏感性和特异性PD以及HC。相同的方法在支持vPSP与HC而非PD的临床诊断中显示出可接受的敏感性和特异性。对于较新的MRPI和P / M版本，也发现了类似的发现。结论有必要进行进一步的研究，以鉴定支持PSP患者临床表型分类的神经影像生物标志物。MRPI和P / M在支持PSP-RS的临床诊断中具有诊断价值。