Effect of color visualization and display hardware on the visual assessment of pseudocolor medical images

Abstract

Purpose: Even though the use of color in the interpretation of medical images has increased significantly in recent years, the ad hoc manner in which color is handled and the lack of standard approaches have been associated with suboptimal and inconsistent diagnostic decisions with a negative impact on patient treatment and prognosis. The purpose of this study is to determine if the choice of color scale and display device hardware affects the visual assessment of patterns that have the characteristics of functional medical images. Methods: Perfusion magnetic resonance imaging (MRI) was the basis for designing and performing experiments. Synthetic images resembling brain dynamic-contrast enhanced MRI consisting of scaled mixtures of white, lumpy, and clustered backgrounds were used to assess the performance of a rainbow ("jet"), a heated black-body ("hot"), and a gray ("gray") color scale with display devices of different quality on the detection of small changes in color intensity. The authors used a two-alternative, forced-choice design where readers were presented with 600 pairs of images. Each pair consisted of two images of the same pattern flipped along the vertical axis with a small difference in intensity. Readers were asked to select the image with the highest intensity. Three differences in intensity were tested on four display devices: a medical-grade three-million-pixel display, a consumer-grade monitor, a tablet device, and a phone. Results: The estimates of percent correct show that jet outperformed hot and gray in the high and low range of the color scales for all devices with a maximum difference in performance of 18% (confidence intervals: 6%, 30%). Performance with hot was different for high and low intensity, comparable to jet for the high range, and worse than gray for lower intensity values. Similar performance was seen between devices using jet and hot, while gray performance was better for handheld devices. Time of performance was shorter with jet.Conclusions: Our findings demonstrate that the choice of color scale and display hardware affects the visual comparative analysis of pseudocolor images. Follow-up studies in clinical settings are being considered to confirm the results with patient images. [http://dx

Interoperable slide microscopy viewer and annotation tool for imaging data science and computational pathology

“…First, grayscale images are typically acquired with 12-bit or 16-bit cameras and stored as 16-bit unsigned integer values, which usually exceed the bit depth of consumer-grade monitors and the sensitivity of the human visual system to differences in signal intensities, requiring intensity values to be rescaled for display and visual interpretation by human readers 48 . Second, grayscale images are often pseudocolored, which can aid in visual interpretation, but can also sometimes mislead human readers 49 . To facilitate display of fluorescence microscopy images, Slim implements the DICOM VOI LUT Transformation and the DICOM Advanced Blending Transformation, which parametrize the conversion of grayscale images with various bit depths into 8-bit pseudocolor images for display on ordinary color monitors and the additive blending of two or more pseudocolor images into a false color image, respectively.…”

“…Of note, Segmentation and Parametric Map objects also allow for the inclusion of VOI and palette color LUTs, enabling the developer or manufacturer of the image analysis algorithm to specify exactly how algorithm outputs should be presented to human readers for visual interpretation. This is critical, because the colormap can have a strong effect on the visual assessment of pseudocolor images by human readers 49 . Slim automatically applies provided LUTs to transform the grayscale images and displays a colorbar along with the generated pseudocolor images to aid the reader in interpreting the data.…”

T2 mapping in myocardial disease: a comprehensive review

“…Rainbow-like color palettes corresponding to colors of the visible spectrum are often the default choice in most post-processing and image visualization toolkits. Although this is useful to highlight small differences in tissue characteristics due to the sharp transitions in color [ 53 ], it can also introduce artificial borders if the myocardial T2 relaxation time change corresponds to a color transition but not necessarily a pathological change. In addition, a small myocardial T2 relaxation time change may be obscured if it is within a given color range [ 54 ].…”

Basal and Acetazolamide Brain Perfusion SPECT in Internal Carotid Artery Stenosis

“…Brain perfusion SPECT images are usually displayed as pseudo-color images converted from grayscale images to improve the diagnostic performance of the interpreters [93]. EANM guideline recommends the use of continuous color tables [55].…”