A comparison of the performance of a 2.4 MP colour

A comparison of the performance of a 2.4 MP colour monitor and a 5.0 MP monochrome monitor in visualising low contrast detail using the CDRAD phantom Poster No.:

C-1358

Congress:

ECR 2018

Type:

Scientific Exhibit

Authors:

S. H. Al-Murshedi, P. Hogg, A. K. Abdullah, A. England; Manchester/UK

Keywords:

Radiographers, Thorax, Digital radiography, Observer performance

DOI:

10.1594/ecr2018/C-1358

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Aims and objectives Monochrome liquid crystal (LCD) display monitors are commonly utilised in diagnostic radiology for medical image viewing. The reason behind this is they have a high luminance compared with the colour liquid crystal display (LCD) monitors[1]. However monochrome LCD monitors are extremely expensive compared with colour LCD monitors; consequently, some institutions use the standard colour liquid crystal display (LCD) monitors even though they have lower luminance [2]. A high luminance is required for monitors utilised in diagnostic radiology[3] because it is important for visualising the entire grayscale, from black to white, of the medical image[2]. According to the American College of Radiology the luminance of a display monitor to be used for primary 2

interpretation of the medical images must be at least 171 cd/m [4]. This study aims to evaluate the impact of display screen, monochrome versus colour, and monitor resolution on the performance of observers in detecting low contrast-detail using a CDRAD phantom.

Methods and materials Image acquisition The CDRAD 2.0 phantom (Department of Radiology, University Hospital Nijmegen, St. Radboud, Netherlands) [5] (Figure 1) was used for image acquisition. The CDRAD phantom was combined with 10 cm medical grade PMMA slabs to simulate the chest region of an adult patient [6, 7]. Six CDRAD phantom images were generated using adults chest radiography protocols with different levels of image quality. Image quality evaluation A 2.4 MP colour liquid crystal display (LCD) monitor (set with maximum luminance 2

of 250 cd/m ) and 5 MP monochrome liquid crystal display (LCD) monitor (set with 2

maximum luminance of 500 cd/m ) were utilised to display the CDRAD phantom images, as illustrated in Figure 2. The Six CDRAD phantom images were evaluated on the two monitors separately by five experienced observers. The images were evaluated in two different ways: firstly, without image manipulation (the observers were not permitted to adjust contrast, intensity

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and magnification); secondly, with image manipulation (the observers were permitted to adjust the contrast, intensity and magnification). The low contrast-detail detectability represented by the image quality figure inverse (IQFinv) were calculated for each image from each observer and the final value of image quality figure inverse (IQFinv) for each image was calculated from taking the average value of the IQFinv for the five observers. The study was undertaken in the same room in order to provide consistency with respect to the room luminance, and an illuminance meter was utilised to ensure that the level of the room luminance was less than 10 lux at the place of the monitor. All the images were presented in DICOM format using free JiveX DICOM Viewer software; Both monitors were calibrated to the Digital Imaging and Communications in Medicine (DICOM) grayscale standard display function (GSDF). Images for this section:

Fig. 1: Illustrates the CDRAD phantom (A) and its radiographic image (B). © Radiography, University of Salford - Manchester/UK

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Fig. 2: An example of set up of CDRAD phantom images evaluation on 5 MP monochrome liquid crystal display (LCD) monitor (A) and 2.4 MP colour liquid crystal display (LCD) monitor (B). © Radiography, University of Salford - Manchester/UK

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Results The average observer image scoring for the six CDRAD phantom images on the 2.4 MP colour liquid crystal display (LCD) monitor and 5 MP monochrome liquid crystal display (LCD) monitor are illustrated in Figure 3 and Figure 4 respectively. The error bars in this chart represents the standard deviation in IQFinv, values resulting from the five observers' scores. Unpaired t-test was used to assess data for statistical significance. The average score of the image quality figure inverse (IQFinv) for the six CDRAD phantom images without image manipulation on both monitors were compared. No significant difference (p=0.64) exists between observers' scores on the two monitors for all images. The average score of the image quality figure inverse (IQFinv) for the six CDRAD phantom images with image manipulation on both monitors were compared. It was observed that there is no significant difference (p=0.74) between observers' image scoring on the two monitors for all images. The 5 MP monochrome liquid crystal display (LCD) monitor has a higher image score but not significant, compared with the 2.4 MP colour liquid crystal display (LCD) monitor, as illustrated in Figure 3 and Figure 4. Images for this section:

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Fig. 3: This bar chart illustrates the average values of observers' scores (IQFinv) for the six CDRAD phantom images on the 2.4 MP colour liquid crystal display (LCD) monitor under the two viewing conditions with and without image manipulation. © Radiography, University of Salford - Manchester/UK

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Fig. 4: This bar chart illustrates the average values of observers' image scoring (IQFinv) for the six CDRAD phantom images on the 5 MP monochrome liquid crystal display (LCD) monitor under the two imaging viewing conditions with and without image manipulation. © Radiography, University of Salford - Manchester/UK

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Conclusion Our study demonstrates that the overall performance of the 2.4 MP colour liquid crystal display (LCD) monitor in visualising of low contrast-detail is not significantly different from that of 5 MP monochrome liquid crystal display (LCD) monitor under the two different viewing conditions with and without image manipulation. Therefore, it seems that the 2.4 MP colour liquid crystal display (LCD) monitor probable to utilise in diagnostic radiology.

Personal information References [1] B. Reiner, E. Siegel, F. Hooper, H. Ghebrekidan, J. Warner, B. Briscoe, Z. Protopapas, and S. Pomerantz, "Variation of monitor luminance on radiologist productivity in the interpretation of skeletal radiographs using a picture archiving and communication system," J. Digit. Imaging, vol. 10, no. S1, pp. 176-176, Aug. 1997. [2] H. Geijer, M. Geijer, L. Forsberg, S. Kheddache, and P. Sund, "Comparison of color LCD and medical-grade monochrome LCD displays in diagnostic radiology," J. Digit. Imaging, vol. 20, no. 2, pp. 114-121, 2007. [3] E. Samei, A. Badano, D. Chakraborty, K. Compton, C. Cornelius, K. Corrigan, M. J. Flynn, B. Hemminger, N. Hangiandreou, J. Johnson, D. M. Moxley-Stevens, W. Pavlicek, H. Roehrig, L. Rutz, J. Shepard, R. a Uzenoff, J. Wang, and C. E. Willis, "Assessment of display performance for medical imaging systems: executive summary of AAPM TG18 report.," Med. Phys., vol. 32, no. 4, pp. 1205-1225, 2005. [4] American College of Radiology (ACR). ACR standard for digital image data management. Available at: http://www.acr.org. 2010. [5] Van der B. R. Thijssen MAO, Bijkerk HR, "Manual CDRAD-phantom type 2.0. Project quality assurance in radiology.," St.Radboud, Netherlands Dep. Radiol. Univ. Hosp. Nijmegen, 1988.

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[6] A. De Crop, K. Bacher, T. Van Hoof, P. V. Smeets, B. S. Smet, M. Vergauwen, U. Kiendys, P. Duyck, K. Verstraete, K. D'Herde, and H. Thierens, "Correlation of ContrastDetail Analysis and Clinical Image Quality Assessment in Chest Radiography with a Human Cadaver Study," Radiology, vol. 262, no. 1, pp. 298-304, 2012.

[7] K. Bacher, P. Smeets, A. De Hauwere, T. Voet, P. Duyck, K. Verstraete, and H. Thierens, "Image quality performance of liquid crystal display systems: Influence of display resolution, magnification and window settings on contrast-detail detection," Eur. J. Radiol., vol. 58, no. 3, pp. 471-479, 2006.

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