Neuropathologic Validation and Diagnostic Accuracy of Presynaptic Dopaminergic Imaging in the Diagnosis of Parkinsonism.

BACKGROUND AND OBJECTIVES: Degeneration of the presynaptic nigrostriatal dopaminergic system is one of the main biological features of Parkinson disease (PD), multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD), which can be measured using single-photon emission CT imaging for diagnostic purposes. Despite its widespread use in clinical practice and research, the diagnostic properties of presynaptic nigrostriatal dopaminergic (DAT) imaging in parkinsonism have never been evaluated against the diagnostic gold standard of neuropathology. The aim of this study was to evaluate the diagnostic parameters of DAT imaging compared with pathologic diagnosis in patients with parkinsonism. METHODS: Retrospective cohort study of patients with DAT imaging for the investigation of a clinically uncertain parkinsonism with brain donation between 2010 and 2021 to the Queen Square Brain Bank (London). Patients with DAT imaging for investigation of pure ataxia or dementia syndromes without parkinsonism were excluded. Those with a pathologic diagnosis of PD, MSA, PSP, or CBD were considered presynaptic dopaminergic parkinsonism, and other pathologies were considered postsynaptic for the analysis. DAT imaging was performed in routine clinical practice and visually classified by hospital nuclear medicine specialists as normal or abnormal. The results were correlated with neuropathologic diagnosis to calculate diagnostic accuracy parameters for the diagnosis of presynaptic dopaminergic parkinsonism. RESULTS: All of 47 patients with PD, 41 of 42 with MSA, 68 of 73 with PSP, and 6 of 10 with CBD (sensitivity 100%, 97.6%, 93.2%, and 60%, respectively) had abnormal presynaptic dopaminergic imaging. Eight of 17 patients with presumed postsynaptic parkinsonism had abnormal scans (specificity 52.9%). DISCUSSION: DAT imaging has very high sensitivity and negative predictive value for the diagnosis of presynaptic dopaminergic parkinsonism, particularly for PD. However, patients with CBD, and to a lesser extent PSP (of various phenotypes) and MSA (with predominant ataxia), can show normal DAT imaging. A range of other neurodegenerative disorders may have abnormal DAT scans with low specificity in the differential diagnosis of parkinsonism. DAT imaging is a useful diagnostic tool in the differential diagnosis of parkinsonism, although clinicians should be aware of its diagnostic properties and limitations. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that DAT imaging does not accurately distinguish between presynaptic dopaminergic parkinsonism and non-presynaptic dopaminergic parkinsonism.

Core surgical training: The influence of time and date on interview outcome.

INTRODUCTION: Core Surgical Training has become increasingly competitive over the last 5 years with the competition ratio reaching 4.16 in 2021 compared to 2.31 in 2015. This is thought to be due to two key factors: a large yearly increase in the number of applicants and an unchanging number of jobs. Steps are taken by HEE to ensure the process is as standardised and fair as possible. Interview date and time selection remains the only aspect of the process that candidates currently control. We aim to explore whether time and date of an interview has any impact on interview scores within CST. METHODS: This study is a national, retrospective cohort study. A freedom of information act request was submitted to HEE to acquire anonymised interview scores and date/time of interview for all CST interviews conducted for the 2022-2023 cohort. RESULTS: Across the two-week period whereby interviews were held 1264 interviews were undertaken. Candidates with morning interviews had a mean score of 111 (±16) and candidates in the afternoon had a mean score of 108 (±18.5) (p = 0.023). Candidates interviewing in week 1 had a mean score of 107 (±18) and candidates interviewing in week 2 had a mean score of 112 (±16.4) (p < 0.001). DISCUSSION: A small difference in score has a significant impact for candidates with their geographical location, specialty choice or event enrolment in the core training programme potentially impacted. It is therefore imperative that these findings receive further evaluation going forward to ensure the process is fair and robust for all participants.