Value of Semiquantitative Analysis for Clinical Reporting of¹²³I-2-β-Carbomethoxy-3β-(4-Iodophenyl)-N-(3-Fluoropropyl)Nortropane SPECT Studies

Abstract

Clinical 123 I-2-b-carbomethoxy-3b-(4-iodophenyl)-N-(3-fluoropropyl)nortropane ( 123 I-FP-CIT) SPECT studies are commonly performed and reported using visual evaluation of tracer binding, an inherently subjective method. Increased objectivity can potentially be obtained using semiquantitative analysis. In this study, we assessed whether semiquantitative analysis of 123 I-FP-CIT tracer binding created more reproducible clinical reporting. A secondary aim was to determine in what form semiquantitative data should be provided to the reporter. Methods: Fifty-four patients referred for the assessment of nigrostriatal dopaminergic degeneration were scanned using SPECT/CT, followed by semiquantitative analysis calculating striatal binding ratios (SBRs) and caudate-to-putamen ratios (CPRs). Normal reference values were obtained using 131 healthy controls enrolled on a multicenter initiative backed by the European Association of Nuclear Medicine. A purely quantitative evaluation was first performed, with each striatum scored as normal or abnormal according to reference values. Three experienced nuclear medicine physicians then scored each striatum as normal or abnormal, also indicating cases perceived as difficult, using visual evaluation, visual evaluation in combination with SBR data, and visual evaluation in combination with SBR and CPR data. Intra-and interobserver agreement and agreement between observers and the purely quantitative evaluation were assessed using k-statistics. The agreement between scan interpretation and clinical diagnosis was assessed for patients with a postscan clinical diagnosis available (n 5 35). Results: The physicians showed consistent reporting, with a good intraobserver agreement obtained for the visual interpretation (mean k 6 SD, 0.95 6 0.029). Although visual interpretation of tracer binding gave good interobserver agreement (0.80 6 0.045), this was improved as SBRs (0.86 6 0.070) and CPRs (0.95 6 0.040) were provided. The number of striata perceived as difficult to interpret decreased as semiquantitative data were provided (30 for the visual interpretation; 0 as SBR and CPR values were given). The agreement between physicians' interpretations and the purely quantitative evaluation showed that readers used the semiquantitative data to different extents, with a more experienced reader relying less on the semiquantitative data. Good agreement between scan interpretation and clinical diagnosis was seen. Conclusion: A combined approach of visual assessment and semiquantitative analysis of tracer binding created more reproducible clinical reporting of 123 I-FP-CIT SPECT studies. Physicians should have access to both SBR and CPR data to minimize interobserver variability.

Individual-Reader Diagnostic Performance and Between-Reader Agreement in Assessment of Subjects with Parkinsonian Syndrome or Dementia Using 123I-Ioflupane Injection (DaTscan) Imaging

“…Several of the studies summarized in this analysis were performed more than 10 y ago, when there was limited experience with 123 I-ioflupane SPECT imaging. Training methods available today (13,14) had not yet been developed or validated, and nuclear medicine physicians had not yet acquired extensive experience in reading the images (18). However, the strong between-reader agreement observed supports previous conclusions (1) that, on the basis of correct imaging procedures and processing, the visual interpretation of the image is independent of the expert conducting the analysis.…”

Safety Analysis of 10 Clinical Trials and for 13 Years After First Approval of Ioflupane 123I Injection (DaTscan)

“…On the contrary, therapeutic indications have been expanded in Europe to include DLB versus AD (in 2006) and early PS (in 2013). As we learn more about it (17,37), DaTscan SPECT appears to be becoming more useful; under indicated circumstances, it is recommended by the European Federation of Neurologic Societies, Movement Disorders Society-EU Section, and European Neurologic Society (38)(39)(40), the Society of Nuclear Medicine and Molecular Imaging (29), and the U.K. National Institute for Health and Clinical Excellence (41).…”

Overview of Dopamine Transporter Imaging in Parkinson’s Disease, Dementia with Lewy Bodies and Other Dementias

“…A combined approach of visual assessment and semiquantitative analysis of tracer binding is often practised and may reduce inter-observer variability [1]. However, both techniques are operator dependent and may introduce small degrees of variability in reporting of results.…”

“…The main clinical application for [(123)I]N-omegafluoropropyl-2beta-carbomethoxy-3beta- [1] nortropane ( 123 I FP-CIT, also called ioflupane) SPECT imaging in clinical use is in distinguishing those cases of tremor (often with possible parkinsonism) where it is clinically difficult to differentiate idiopathic Parkinson's disease (PD) from essential tremor, dystonic tremor or drug-induced parkinsonism. However, this imaging modality cannot differentiate between PD and Parkinson-plus syndromes such as multiple system atrophy (MSA), progressive supranuclear palsy (PSP) and corticobasal ganglionic degeneration (CBGD).…”