POMD01 Blinded analysis of conventional MRI in a cohort of pathologically confirmed parkinsonian illnesses

Abstract

BackgroundAlthough conventional MRI (cMRI) has been reported to show specific abnormalities in parkinsonism, the diagnosis of the underlying pathology can be challenging. We report the radiological diagnostic accuracy, and the sensitivity, specificity, positive (PPV) and negative predictive values (NPV) of cMRI abnormalities in a pathologically confirmed cohort of Parkinson's disease (PD), progressive supranuclear palsy (PSP), multiple system atrophy (MSA) and corticobasal degeneration (CBD).MethodcMRI of donors to a neurological brain bank was reviewed by two experienced neuroradiologists blinded to clinical details. Images were systematically reviewed for the presence of specific reported abnormalities.Results48 pathologically confirmed cases (23 PSP, 6 PD, 13 MSA and 6 CBD) and nine controls were studied. The final clinical diagnosis was supported in 68% and the radiological diagnosis in 60%. Using cMRI 55% of PSP, 67% of PD, and 77% of MSA were correctly identified. In this study the Hummingbird sign has 68% sensitivity, 100% specificity and PPV for PSP and the Hot Cross Bun has 62% sensitivity, 100% specificity and PPV for MSA.ConclusionThe confirmation that using cMRI key diagnostic features with very high specificity and PPV have low sensitivity endorses the development of newer MR techniques (e.g., high field diffusion tensor imaging) as useful biomarkers early in disease.

Signo del colibrí

“…También hay ovillos neurofibrilares con apariencia globosa y pérdida neuronal y glial mesencefálica.Hallazgos imagenológicosEl signo del colibrí se observa en el plano sagital de la RM de encéfalo en pacientes con atrofia del mesencé-falo sin compromiso significativo de la protuberancia. Tiene una especificidad cercana al 100% y una sensibilidad variable, dado que se hace evidente en estadios tardíos de la enfermedad5 . Su ausencia en pacientes con atrofia multisistémica y enfermedad de Parkinson es fundamental para el diagnóstico diferencial de estas entidades con sintomatología similar 2,4 .…”