Posted online August 15, 2014 at http:// www. ada. org / epubs / highroad / jadaRadiology / 081314. html # one Copyright © 2014 American Dental Association. All rights reserved. Reprinted with permission.
Are consumer, tablet and 6MP displays equally useful for detecting anatomical and pathological structures?
It depends on who is interpreting the images, research published in the July 2014 issue of Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology says.
With new technologies come potentially useful mobile devices and radiology applications. However, scientists in Finland could find only one study evaluating the effect of liquid-crystal displays on diagnostic performance of panoramic radiographs and none on tablet use.
Their aim, therefore, was to compare observer performance in detecting both anatomical and pathological structures in panoramic radiographs using consumer grade and tablet displays under suboptimal conditions as compared to the 6MP( megapixels) display calibrated with Gray Scale Standard Display Function under low ambient light conditions. Their research hypothesis was that medical display in low ambient light conditions is better than consumer grade display or tablet under high ambient light.
To investigate, the researchers selected 30 panoramic radiographs showing clearly visible structures. After an hour of training on how to use viewing programs, two observers with different levels of interpreting experience evaluated all images on each of the three display types.
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Observer 1 was an oral and maxillofacial radiologist with eight years of experience. Observer 2 was a resident in oral and maxillofacial radiology with two years of interpreting experience. They evaluated images on the consumer grade display and the tablet during the first session and on the 6MP display three weeks later. They were each allowed one minute per image to evaluate seven different anatomical structures and pathological lesions from the left side of the jaw.
The observers used a five-point scaling system:
1. definitely not a finding; 2. probably not a finding; 3. unable to evaluate; 4. probably a finding; 5. definitely a finding.
When successful ratings were tallied, researchers found that the less experienced observer performed significantly worse on a 30.4 inch tablet as compared to a 30.4 inch 6MP display in identifying dentinal caries in the lower molar and periapical lesions in the upper molar in panoramic radiographs under bright-light conditions. The more experienced observer performed similarly on the tablet and 6MP display.
In discussion, the researchers noted that other studies evaluating the accuracy of radiographic methods have shown significant differences in diagnostic performance between individual observers and have attributed this to differences in experience, training or visual perception.
“ With regards to visual perception, in low lighting conditions the rods in the eye are activated and small differences in gray scale between pixels on the monitor can be seen. Conversely, at bright lighting levels, the rods are less active and small contrast differences are more difficult to observe,” the authors explained in discussion.
They cited previous supporting research.“ To associate with differences in experience, training or visual perception, it seems that a more experienced radiologists sees more shades of gray.”
They concluded that a dentist in the early phases of training in interpreting panoramic images may be more dependent on a high-quality medical display used under optimal viewing conditions, while an experienced dentist can achieve high diagnostic standards using suboptimal diagnostic technology. �