A JAFROC study of nodule detection performance in CT images of a thorax acquired during PET/CT

Thompson, JD, Wareing, AK, Szczepura, K, Vinjamuri, S and Hogg, P 2017, 'A JAFROC study of nodule detection performance in CT images of a thorax acquired during PET/CT' , Radiography .

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Abstract

Purpose Two types of CT images (modalities) are acquired in PET/CT: for attenuation correction (AC) and diagnosis. The purpose of the study was to compare nodule detection and localization performance between these two modalities. Methods CT images, using both modalities, of an anthropomorphic chest phantom containing zero or more simulated spherical nodules of 5, 8, 10 and 12 mm diameters and contrasts −800, −630 and 100 HU were acquired. An observer performance study using nine observers interpreting 45 normal (zero nodules) images and 47 abnormal images (1–3 nodules; average 1.26) was conducted using the free-response receiver operating characteristic (FROC) paradigm. Data were analysed using an R software package implemented jackknife alternative FROC (JAFROC) analysis. Both empirical areas under the equally weighted AFROC curve (wAFROC) and under the highest rating inferred ROC (HR-ROC) curve were used as figures of merit (FOM). To control the probability of Type I error test alpha was set at 0.05. Results Nodule detection as measured by either FOM was significantly better on the diagnostic quality images (2nd modality), irrespective of the method of analysis, [reader averaged inter-modality wAFROC FOM difference = −0.07 (−0.11,−0.04); reader averaged inter-modality HR-ROC FOM difference = −0.05 (−0.09, −0.01)]. Conclusion Nodule detection was statistically worse on images acquired for AC; suggesting that images acquired for AC should not be used to evaluate pulmonary pathology. Keywords PET/CT; Nodule detection; JAFROC

Item Type: Article
Schools: Schools > School of Health Sciences > Centre for Health Sciences Research
Journal or Publication Title: Radiography
Publisher: Elsevier
ISSN: 1078-8174
Related URLs:
Depositing User: Dr JD Thompson
Date Deposited: 28 Mar 2017 10:57
Last Modified: 10 Aug 2017 13:27
URI: http://usir.salford.ac.uk/id/eprint/42023

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