Chapter 3, Problem 133P

Radiology

Mobile displays have the potential to increase the flexibility of consulting radiologists if they can be shown to be comparable to traditional display modalities. A study was performed comparing a mobile display iPad 2 with a larger liquid crystal display (LCD) for the diagnosis of tuberculosis (TB) on chest radiography (Abboud et al., [19]). De-identified images of 240 chest X-rays were transferred from a PACS workstation (LCD) to an iPad 2 tablet. The images were reviewed independently by 5 radiologists and were graded as positive or negative for TB on both the LCD and the iPad 2. The reviews occurred at different times to avoid recall bias.

A database of > 500 chest X-rays was created from TB screening films over a 4-month period. Of these, 200 cases originally interpreted as TB-negative and 40 cases originally interpreted as TB-positive were selected at random for study. The images were re-reviewed using both an LCD and an iPad 2 imaging display, albeit at different times. The results were as shown in Table 3.21.

Table 3.21 Comparison of TB screening results using an LCD and iPad 2 display

If we regard the LCD interpretation as the gold standard, then what is the specificity of the iPad 2 interpretation?