Observer accuracy in the detection of pulmonary nodules on CT: effect of cine frame rate

Aim: To assess the effect of cine frame rate on the accuracy of the detection of pulmonary nodules at computed tomography (CT). Materials and methods: CT images of 15 consecutive patients with (n = 13) or without (n = 2) pulmonary metastases were identified. Initial assessment by two thoracic radiologists provided the 'actual' or reference reading. Subsequently, 10 radiologists [board certified radiologists (n = 4) or radiology residents (n = 6)] used different fixed cine frame rates for nodule detection. Within-subjects analysis of variance (ANOVA) was used to evaluate the data. Results: Eighty-nine nodules were identified by the thoracic radiologists (median 8, range 0-29 per patient; median diameter 9 mm, range 4-40 mm). There was a non-statistically significant trend to reduced accuracy at higher frame rates (p = 0.113) with no statistically significant difference between experienced observers and residents (p = 0.79). Conclusion: The accuracy of pulmonary nodule detection at higher cine frame rates is reduced, unrelated to observer experience.