Investigation of optimal viewing size for detecting nodular ground-glass opacity on high-resolution computed tomography with cine-mode display

Abstract

We evaluated the effect of the displayed image sizes on observers' ability to detect nodular ground-glass opacity (n-GGO) on CT and investigated the optimal viewing size for soft-copy reading at CT screening for lung cancer. A total of 46 patients' high-resolution computed tomography (HRCT) images (22 patients with one GGO; 24 without GGO) were displayed on a monochromatic liquid crystal display monitor at a resolution of 1,200 × 1,600. HRCT was presented on the screen with cine-mode display. We compared two viewing sizes (original size, i.e., the image displayed with a zoom factor of 1 in which each pixel value in the image is displayed as one pixel on the display: 13 cm × 13 cm; fit size, i.e., by zooming the captured image until it occupies the entire screen: 30 cm × 30 cm) in terms of radiologists' performance for detecting n-GGO on HRCT and the viewing times required for soft-copy reading decisions. Observer performance was analyzed in terms of the receiver operating characteristic (ROC) curve. A statistically significant improvement was found with the original size in the average area-under-the-ROC curve values for the accuracy of diagnosis and the viewing times compared to the fit size (P < 0.05). The original size with cine-mode display leads to increased lung GGO detection at CT screening for lung cancer, and the reduced time spent performing the diagnosis offers cost savings.

Image Size Influences Visual Search and Perception of Hemorrhages When Reading Cranial CT

“…The magnitude of the difference in the JAFROC FOM is roughly comparable to the difference found by Gur et al (2006). However, Yamaguchi et al (2011) found much greater, statistically significant differences between small and large images. Although the size of the images used in their study is comparable to the size of the images used in our experiment, a possible reason for this difference might be the use of different types of stimulus material.…”

“…The empirical evidence with regard to the influence of image size on performance is mixed: Several studies that used tile-mode CT, meaning that slices were presented next to each other on a light box (Schaefer at al., 1992;Seltzer, Judy, Feldman, Scarff, & Jacobson, 1998), or single radiographs (Bessho, Yamaguchi, Fujita, & Azuma, 2009) showed disadvantages for small images (12 × 12 cm to 15 × 15 cm) compared to large images (30 × 30 cm), as measured by the area under the receiver operating characteristic (ROC) curve. However, two studies that were conducted to ascertain performance relative to image size differences have shown slight advantages for small images (Gur et al, 2006;Yamaguchi et al, 2011). In these experiments, stackmode CT images were used, meaning that slices were presented individually on the monitor and radiologists scrolled through them at their own pace.…”

Does preference influence performance when reading different sizes of cranial computed tomography?

“…Interestingly, the participants nonetheless rated the large images as more comfortable to interpret. Yamaguchi et al 4 also found a statistically significant advantage for small images (13 × 13 cm) compared with enlarged ones (30 × 30 cm) regarding the area under the ROC curve when identifying nodular ground-glass opacity on CT displayed in cine mode. Although Yamaguchi et al did not report a systematic evaluation of comfort, they mentioned that all seven interpreters strongly indicated that the original image size of 13 × 13 cm was easier to interpret.…”

“…To date, there is only a very limited number of studies that have focused on the effects of image size and its importance for diagnostic performance. [1][2][3][4][5] Interestingly, the results of these studies are mixed.…”