Demonstration of correlations between clinical and physical image quality measures in chest and lumbar spine screen-film radiography

The ability to predict clinical image quality from physical measures is use ful for optimization in diagnostic radiology. In this work, clinical and ph ysical assessments of image quality are compared and correlations between t he two are derived. Clinical assessment has been made by a group of expert radiologists who evaluated fulfilment of the European image criteria for ch est and lumbar spine radiography using two scoring methods: image criteria score (ICS) and visual grading analysis score (VGAS). Physical image qualit y measures were calculated using a Monte Carlo simulation model of the comp lete imaging system. This model includes a voxelized male anatomy and was u sed to calculate contrast and signal-to-noise ratio of various Important an atomical details and measures of dynamic range. Correlations between the ph ysical image quality measures on the one hand and the ICS and VGAS on the o ther were sought. 16 chest and 4 lumbar spine imaging system configurations were compared in frontal projection. A statistically significant correlati on with clinical image quality was found in chest posteroanterior radiograp hy for the contrast of blood vessels in the retrocardiac area and a measure of useful dynamic range. In lumbar spine anteroposterior radiography, a si milar significant correlation with clinical image quality was found between the contrast and signal-to-noise ratio of the trabecular structures in the L1-L5 vertebrae. The significant correlation shows that clinical image dua lity can, at least in some cases, be predicted from appropriate measures of physical image quality.