The influence of different technique factors on image quality of chest radiographs as evaluated by modified CEC image quality criteria

The influence of different technique factors on image quality of chest radiographs as evaluated by modified CEC image quality criteria

B Lanhede, MSc ¹ M Båth, MSc ¹ S Kheddache, PhD, MD ² P Sund, MSc ¹ L Björneld ² M Widell ¹ A Almén, PhD ³ J Besjakov, PhD, MD ⁴ S Mattsson, PhD ³ A Tingberg, PhD ³ C Herrmann, PhD ⁵ W Panzer, MSc ⁵ M Zankl, MSc ⁵ and L G Månsson, PhD ¹

¹Department of Radiation Physics, Göteborg University, Sahlgrenska University Hospital, SE-413 45 Göteborg, Sweden, ²Department of Radiology, Sahlgrenska University Hospital, SE-413 45 Göteborg, Sweden, ³Department of Radiation Physics, Lund University, Malmö University Hospital, SE-205 02 Malmö, Sweden, ⁴Department of Diagnostic Radiology, Malmö University Hospital, SE-205 02 Malmö, Sweden and ⁵GSF-National Research Center for Enviroment and Health, D-857 64 Neuherberg, Germany^,

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Figure 1. Percentage of chest radiographs fulfilling a certain number of image quality criteria.

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Figure 2. The image criteria score (ICS) for each of the 16 testedchest imaging techniques for six observers (excluding the "strict" observer) ( ${blacksquare}$ ) and seven observers ( ${square}$ ).

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Figure 3. The maximum and minimum values of image criteria score for individual observers (ICS_o) for each of the 16 tested chest imaging techniques for seven observers and six observers (excluding the "strict" observer).

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Figure 4. Comparison of the relative results from the image criteria score (ICS) and the visual grading analysis score (VGAS). The techniques are arranged in order of decreasing values of ICS (percentage of fulfilled criteria) ( ${blacksquare}$ ), and for each technique the corresponding value of VGAS ( ${square}$ ) is shown. Techniques that cannot be statistically separated from each other (p<0.05) using the ICS are joined by a horizontal line in the upper part of the figure, whereas those that cannot bestatistically separated using the VGAS are joined by a horizontal line in the lower part of the figure.

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Figure 5. Plot of image criteria score (ICS) against H_Golem for the 16 techniques. Each data point is represented by a box divided into four quadrants, which describes the technique by the following code. Top left quadrant, tube voltage ( ${blacksquare}$ , 102 kVp; ${square}$ 141 kVp); top right, method for scatter reduction ( ${blacksquare}$ , air gap, ${square}$ , grid); bottom left, optical density ( ${blacksquare}$ , 1.3, ${square}$ , 1.8); bottom right, nominal speed class ( ${blacksquare}$ , 160, ${square}$ , 320). (The code is also explained in the figure for clarity.) The average standard error of the ICS is 0.029 (range 0.022–0.034). The average relative standard error of H_Golem is 0.11 (range 0.07–0.15). Typical standard errors in two areas are shown.

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Figure 6. Image criteria score (ICS_c) for each criterion at the two states of each parameter. The four original CEC quality criteria are presented in (a) and the modifed quality criteria in (b). Error bars are ±1 SEM.