Grading image quality in chest radiography

We attempted to grade image quality using three different criteria namely Anatomical (A), Physical (P) and Overall (O), with a total score of 100 for each. The anatomic criterion included grading in terms of the extent of visualisation optimal, adequate, poor or nil, on both sides, one side, or no visualisation, etc.) of cortical margins, trabecule, diaphragm, trachea, retrocardiac area (left diaphragm and spine), retrodiaphragmatic lung tissue and pulmonary vasculature. The physical criteria included contrast, density, positioning and details. Evaluation of 184 chest radiographs demonstrated that all the three criteria matched only in 33% of the cases indicating that no criterion alone is sufficient. If A was assumed to be 100% accurate, then P was 84% and O, 76%. Image quality analysis showed that the poorly shown areas were the spine, trachea and retrodiaphragmatic lung tissue. This helped us change our technique so as to optimise the quality of all regions in the radiograph besides providing an index of quality and making day-to-day monitoring of quality possible in a more objective manner.

Duke Scholars

Author Madan Mohan Rehani Radiology