CHICAGO - Personal preference as a metric of usability may sometimes seem arbitrary and contrived. However, researchers at M.D. Anderson Cancer Center in Houston, TX designed a study to measure radiologists' preference for film-screen x-rays vs. images acquired via digital x-ray that removed the capability for capriciousness.
Dr. Bradley Sabloff presented the work of his team during the chest digital radiography session at the RSNA late Monday afternoon. Sabloff and his colleagues assessed radiologists' image preference in a paired discriminatory setting by comparing normal anatomic structures depicted on chest radiographs acquired with conventional film screen against those acquired with amorphous silicon flat panel digital radiography (DR).
The study gathered conventional film-screen and DR posteroanterior (PA) and lateral chest radiography performed on 50 patients (28 men and 22 women), following informed consent. All images were obtained with dedicated chest units: film-screen with a Siemens Thoramat, DR on a GE Revolution that had similar x-ray tube and generator characteristics.
The images were then processed according to established parameters. The DR image processing included a pre-commercial version of GE's tissue-equalization software, a program to improve contrast in dense areas without compromising overall image quality.
The film-screen images were printed on a Sterling/Agfa Ultravision Rapid/Ultravision Ci. The DR images were printed on a Fuji FDPL dry printer using Fuji dry film. The images were displayed using a side-by-side format alternating technologies in the center position. There were 11 PA sets and 5 lateral sets of images for review.
The cases were read independently by five board-certified radiologists (three trained in thoracic fellowships and two trained in musculoskeletal fellowships). The visualization of anatomic structures, lungs, mediastinum, pleura, and bone were graded on a 5-point scale. The reader's preference for the overall image was also assessed.
On PA radiographs, a strong grading trend (61%) favoring the DR images was noted with respect to the retrocardiac region, the subdiaphragmatic region, and the pulmonary vasculature. Bony detail of the ribs and the spine were also scored higher for DR on both PA and lateral (53%) radiographs. DR PA images were graded higher than conventional film-screen images at the lung apices, the pulmonary hila, and the azygo-espohageal region, and for visualization of the fissures.
Sabloff reported that with respect to image noise, film-screen images were preferred. But at equivalent speed settings the PA and lateral radiograph film-screen combination had a 84% greater patient x-ray exposure than DR, and the PA film-screen alone had a 109% exposure.
Sabloff and his colleagues found that printed DR images were scored higher than printed film-screen images in all areas by their group of radiologists. Overall image preference favored the DR images processed with tissue equalization, rather than those obtained via conventional film-screen technique.
By Jonathan S. Batchelor
AuntMinnie.com staff writer
November 27, 2001
For the rest of our coverage of the 2001 RSNA meeting, go to our RADCast@RSNA 2001.
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