The potential value of a pictorial atlas for aid in the visual diagnosis of ¹²³I FP-CIT SPECT scans

Summary

The aim of our study was to evaluate the value of a pictorial atlas of ¹²³I FP-CIT SPECT images for aid in the visual diagnosis. Patients, materials, methods: Sixty patients, of whom 20 were clinically diagnosed as ‘non-parkinsonian’ and 40 as having Parkinson's disease or any related disorder, were included in the study. An atlas consisting of 12 ¹²³I FP-CIT SPECT images was constructed first. Validity of the atlas was investigated by performing a receiver operating characteristic (ROC) analysis with the clinical diagnosis as the gold standard. The remaining 48 SPECT images were visually assessed twice by 5 observers, first with and secondly without consulting the atlas, or vice versa. The added value of the atlas was investigated by comparing the diagnostic accuracy and the interobserver variability for both methods. Results: ROC analysis performed on the atlas yielded an area under the curve of 1 for a threshold discriminating between clinically non-parkinsonian and parkinsonian patients that was situated between image 4 and 5 of the atlas. For the diagnostic accuracy, we found that the area under the ROC curve was systematically higher if observers had access to the atlas compared to when they had not (Wilcoxon's test, p<0.05). Also, the interobserver variability was significantly lower when observers used the atlas when compared to when they did not (p = 0.05). Conclusion: Diagnostic accuracy was significantly higher and interobserver variability significantly lower if observers had access to the atlas compared to when they had not. Hence, having a pictorial atlas available may facilitate the visual assessment of ¹²³I FP-CIT SPECT scans.

Zusammenfassung

Ziel: Nutzeneinschätzung eines Bildatlas mit ¹²³I-FP-CIT-SPECT-Abbildungen als Unterstützung der visuellen Diagnostik. Patienten, Material, Methoden: 60 Patienten, von denen 20 als asklinisch “nicht-parkinsonkrank” und 40 mit M. Parkinson oder verwandten Erkrankungen diagnostiziert waren, wurden in die Studie eingeschlossen. Zuvor wurde ein Atlas, bestehend aus 12 ¹²³I-FP-CIT-SPECT-Abbildungen, zusammengestellt. Dessen Validität wurde mit einer Receiver-Operating-Characteristic( ROC)-Analyse mit der klinischen Diagnose als Goldstandard geprüft. Die verbleibenden 48 SPECT-Bilder wurden von fünf Gutachtern zweimal visuell beurteilt, erst mit, dann ohne Atlas, oder umgekehrt. Der Zusatznutzen des Atlas wurde untersucht, indem man die diagnostische Exaktheit und die Variabilität zwischen den Gutachtern für beide Methoden verglich. Ergebnisse: Die ROC-Analyse bezüglich des Atlas ergab eine Fläche unter der Kurve (AUC) von 1 für eine zwischen Abbildung 4 und 5 des Atlas liegende Schwelle, die zwischen klinisch nicht Parkinsonkranken und Parkinson-Patienten diskriminierte. Hinsichtlich der diagnostischen Exaktheit wurde festgestellt, dass die Fläche unter der ROC-Kurve systematisch höher war, wenn die Gutachter Zugriff auf den Atlas hatten, als wenn sie diesen nicht hatten (Wilcoxon Test, p < 0,05). Auch die Variabilität zwischen den Gutachtern war signifikant niedriger, wenn sie den Atlas benützten (p = 0,05). Schlussfolgerung: Die diagnostische Exaktheit war signifikant höher und die Variabilität zwischen den Gutachtern signifikant niedriger, wenn diese Zugriff auf den Atlas hatten als wenn sie ihn nicht hatten. Daher könnte ein Bildatlas die visuelle Diagnostik von ¹²³I FP-CIT-SPECT-Scans erleichtern.

Keywords

¹²³I FP-CIT - single photon emission computed tomography - visual diagnosis - pictorial atlas

Schlüsselwörter

¹²³I FP-CIT - Single-Photon-Emissionscomputertomographie - visuelle Diagnostik - Bildatlas

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