Interobserver reproducibility of the interpretation of I-123 FP-CIT single-photon emission computed tomography
Marianne C. Tondeura, Anne-Sophie Hambyeb, Sophie Dethyc and Hamphrey R. Hamd
Objectives I-123 ioflupane (FP-CIT) single-photon emission computed tomography is a recognized tool in the diagnosis of Parkinsonian syndromes. In practice, data interpretation relies onvisual and semiquantitative analyses. Good interobserver reproducibility is a prerequisite before claiming the robustness of a technique. This study aimed at evaluating interobserver reproducibility of this approach. Methods Thirty nuclear medicine physicians participated in the study. Data included FP-CIT images and semiquantitative measurements of 12 cases, covering a wide spectrum ofscintigraphic patterns and for which a ‘true’ clinical diagnosis based on long-term follow-up was available. Interobserver agreement was defined, for each case, as the highest percentage reached among the three proposed answers with complete agreement arbitrarily set at 80% or more. Variability in an individual observer’s sensitivity to assess data as normal, equivocal or abnormal was scored using athree-point scale. Results Response rate was 99.7%. Among the three possible answers, ‘normal’ accounted for 41.2% of the total, ‘abnormal’ for 49.8% and ‘equivocal’ for 8.1%. The mean interobserver agreement was 76% (range: 37–100%), with complete agreement being reached only in five cases. The interpretation proposed by most observers accorded to clinical diagnosis in 75% of the cases. Abnormalities ofthe central nervous system were encountered in all the cases with disagreement between the observer’s interpretation and clinical diagnoses. An important variability in the observers’ sensitivity was seen. Conclusion In the particular setting of this preliminary study evaluating the reproducibility of FP-CIT single-photon emission computed tomography interpretation in a group of nuclear medicinephysicians with various experiences, interobserver agreement was suboptimal. Collegial discussion and standardized interpretation criteria could contribute to an improved c reproducibility. Nucl Med Commun 31:717–725 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins.
Nuclear Medicine Communications 2010, 31:717–725 Keywords: agreement, I-123 ioflupane single-photon emission computedtomography, interobserver, Parkinson, reproducibility
a Service des Radio-Isotopes, CHU Saint-Pierre, Bruxelles, bService des ` Radio-Isotopes, cService de Neurologie, CHU de Tivoli, La Louviere and d UZ Gent, Dienst Isotopen, De Pintelaan 185, Gent, Belgium
Correspondence to Marianne Tondeur, Service des Radio-Isotopes, CHU Saint-Pierre, Rue Haute 322, 1000 Bruxelles, Belgium Tel: + 32 2 535 4598; fax: + 32 2 535 31 37; e-mail: Marianne_Tondeur@stpierre-bru.be Received 12 February 2010 Revised 28 April 2010 Accepted 28 April 2010
Until recently, differentiation between idiopathic Parkinson’s disease (IPD) from Parkinsonian syndromes relied on clinical symptoms, pharmacological tests and response to treatment. Misdiagnosis was, however, not rare especially early in thecourse of the disease, as shown in a large neuropathological study published in the early 1990s, in which an error rate of 24% was reported between clinical diagnosis and neuropathological findings [1,2]. The introduction of PET and single-photon emission computed tomography (SPECT) tracers for noninvasive imaging of the nigrostriatal system has dramatically modified the deal and improved thediagnostic accuracy, especially in doubtful cases. I-123 ioflupane (DaTSCAN, GE Healthcare Ltd, Little Chalfont, UK or FP-CIT), a cocaine derivative with high affinity for the dopamine transporter, has now a wellestablished role in the differential diagnosis of Parkinsoc 0143-3636 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins
nian syndromes [3–9], with a sensitivity of above 95% and...
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