Perceived Color Gamut in Images: From Boundary to Difference.

A larger display color gamut volume (CGV) is expected to produce higher perceived brightness and colorfulness of the images displayed. However, display control algorithms such as gamut mapping and color conversion need to be carefully controlled to fully take advantage of the higher luminance and more saturated display primaries. Using RGBW displays (RGB plus a white channel) as a special case in contrast to RGB displays, it is demonstrated that a larger RGB display gamut enclosed by the boundary did not guarantee a larger color gamut perceived in images. Five gamuts with different white channel contributions were simulated, and seven different image contents were curated and rendered on each display. Using a paired comparison experiment with 33 observers, the perceived scales of color gamut as perceived brightness and colorfulness were derived. The results show more correlation with the image-wise than display-wise CGV and can be explained with image color differences. Our findings highlight the importance of considering image contents when optimizing display gamut volume, which can be guided by such image-wise analysis.

Quantitative assessment of the subepithelial collagen band does not increase the accuracy of diagnosis of collagenous colitis.

The thickness of eosinophilic band in collagenous colitis (CC) was assessed by 3 methods: histologic estimates (22 observers), conventional measurements using a calibrated micrometric scale (1 observer), and semiautomatic micrometric measurements (1 observer). By the histologic estimate technique, 7.4% of the results failed to diagnose CC; by calibrated micrometry, the failure was 6% and by semiautomatic micrometry, 6%. The main difficulty in measuring the thickness of the CC band is that the deeper border of the band appears fuzzy and hairy-irregular. CC should be defined not exclusively on the basis of the thickness of the collagen table, but as a microscopic constellation characterized by a distorted superficial cell arrangement, with areas of epithelial denudation and inflammatory cells in the superficial epithelium and the lamina propria. In agreement with Lazenby's statement: "Focusing solely on the collagen band can result in both over- and underdiagnosis"

The WHO classification of MDS does make a difference.

The purpose of this study was to determine the facility and reliability of the World Health Organization (WHO) classification of myelodysplastic syndromes (MDSs) with several observers reviewing the same diagnostic specimens. We also wanted to determine if the WHO classification provided additional information about predictability of clinical response outcome. To accomplish these goals we reviewed 103 previously diagnosed cases of low-risk MDS. We found 92% interobserver agreement (P <.001). Sixty-four of these patients had been entered into clinical trials using growth factors by the Nordic MDS Study Group. The WHO classification reliably predicted therapeutic response to the combination of granulocyte colony-stimulating factor (G-CSF) and erythropoietin (Epo). The response rate differed significantly between refractory anemia with ringed sideroblasts (RARS) and refractory anemia with multilineage dysplasia and ringed sideroblasts (RCMD/RS) with regard to therapeutic response (75% versus 9%; P =.003). Also, in the group of patients with less than 5% marrow blasts, there was a difference in median survival between patients with unilineage dysplasia (51% surviving at 67 months) and those with multilineage dysplasia (median survival, 28.5 months; P =.03).