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Lung nodule detection in pediatric chest CT: Quantitative relationship between image quality and radiologist performance
Author(s) -
Li Xiang,
Samei Ehsan,
Barnhart Huiman X.,
Gaca Ana Maria,
Hollingsworth Caroline L.,
Maxfield Charles M.,
Carrico Caroline W. T.,
Colsher James G.,
Frush Donald P.
Publication year - 2011
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3582975
Subject(s) - hounsfield scale , nodule (geology) , receiver operating characteristic , medicine , radiology , image quality , nuclear medicine , image noise , lung , lung cancer , computed tomography , pathology , image (mathematics) , paleontology , artificial intelligence , computer science , biology
Purpose : To determine the quantitative relationship between image quality and radiologist performance in detecting small lung nodules in pediatric CT.Methods : The study included clinical chest CT images of 30 pediatric patients (0–16 years) scanned at tube currents of 55–180 mA. Calibrated noise addition software was used to simulate cases at three nominal mA settings: 70, 35, and 17.5 mA, resulting in quantum noise of 7–32 Hounsfield Unit (HU). Using a validated nodule simulation technique, lung nodules with diameters of 3–5 mm and peak contrasts of 200–500 HU were inserted into the cases, which were then randomized and rated independently by four experienced pediatric radiologists for nodule presence on a continuous scale from 0 (definitely absent) to 100 (definitely present). The receiver operating characteristic (ROC) data were analyzed to quantify the relationship between diagnostic accuracy (area under the ROC curve, AUC) and image quality (the product of nodule peak contrast and displayed diameter to noise ratio,CDNR display).Results : AUC increased rapidly from 0.70 to 0.87 whenCDNR displayincreased from 60 to 130 mm, followed by a slow increase to 0.94 whenCDNR displayfurther increased to 257 mm. For the average nodule diameter (4 mm) and contrast (350 HU), AUC decreased from 0.93 to 0.71 with noise increased from 7 to 28 HU.Conclusions : We quantified the relationship between image quality and the performance of radiologists in detecting lung nodules in pediatric CT. The relationship can guide CT protocol design to achieve the desired diagnostic performance at the lowest radiation dose.]