A new visual rating scale for Ioflupane imaging in Lewy body disease

Abstract

BackgroundDopaminergic loss on 123I-Ioflupane brain imaging is a recognised biomarker for dementia with Lewy bodies. It is usually assessed using a visual rating scale developed for Parkinson's disease, which may not be optimal for dementia with Lewy bodies, as patterns of dopaminergic loss can be different.ObjectivesWe aimed to develop a new visual rating scale for 123I-Ioflupane brain images in Lewy body disease that encompasses appearances seen in dementia with Lewy bodies, and validate this against autopsy diagnosis.MethodsFour experienced observers developed and tested a new scale consisting of two metrics, reflecting overall loss and heterogeneity of loss. 66 subjects were used during development including clinical diagnoses of Alzheimer's disease (n = 14), Parkinson's disease (n = 9), Parkinson's disease dementia (n = 9), dementia with Lewy bodies (n = 15) and normal controls (n = 19). The scale was then tested on an independent group of 46 subjects with autopsy confirmed diagnosis: Alzheimer's disease (n = 11), Parkinson's disease (n = 3), Parkinson's disease dementia (n = 15), dementia with Lewy bodies (n = 12), normal controls (n = 4) and Frontotemporal dementia (n = 1).ResultsIn the autopsy validation the sensitivity and specificity of the new scale for Lewy body disease was 97% and 100% respectively, compared with the standard scale which had the same sensitivity (97%), but lower specificity (80%). The new scale had excellent inter rater reliability (intra-class correlation coefficient 0.93).ConclusionA new robust and reliable rating scale is described that straightforwardly captures the visual appearance of 123I-Ioflupane brain images. It demonstrated high accuracy in autopsy confirmed cases and offers advantages over the existing visual rating scale.

Dementia with Lewy bodies: an update and outlook

“…FP-CIT SPECT images can be rated visually using a scale developed for PD [42], though many cases of DLB are difficult to classify using this scale (Fig. 1a) [43]. Clinical reports often use a combination of visual interpretation and semi-quantitative analysis, which has been shown to increase reader confidence [44, 45].…”

Accuracy of dopaminergic imaging as a biomarker for mild cognitive impairment with Lewy bodies

“…Mild balanced loss of dopaminergic uptake throughout both striata was designated as within normal limits, as this pattern was seen in controls in our paper using autopsy-confirmed diagnoses. 32 Moderate-to-severe balanced loss was rated abnormal. After rating all scans, any scan where there was not agreement between at least four raters was then subsequently reviewed at a panel meeting, where a full consensus rating of normal or abnormal was agreed.…”

Impact of the size of the normal database on the performance of the specific binding ratio in dopamine transporter SPECT

“…This does not rule out that the other conventional semi-quantitative parameters might provide additional information beyond the putaminal SBR in other patient samples, for example, in samples with more borderline cases or a larger fraction of atypical neurodegenerative PS (multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration), or in the differentiation between dementia with Lewy bodies and Alzheimer's disease [42]. Authors' contributions HSS did the data analysis, interpretation of study results, and manuscript drafting.…”