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10 cm distance at perpendicular line is measured from 1 cm to 11 cm (black arrows) below the scan

2 Fig. 1. Dead zone. Nine echoes are positioned 2-10 mm below the scan surface with 1 mm distance. All nine echoes are clearly visualized. 534 Fig. 2. Vertical and horizontal measurement. 10 cm distance at perpendicular line is measured from 1 cm to 11 cm (black arrows) below the scan surface for the vertical measurement, and 8 cm between horizontal targets (white arrows) are measured for the horizontal measurement.

Transverse length of targets located at 6 cm and 10 cm in depth are measured for the evaluation of focal zone.

3 Fig. 3. Focal zone and axial/lateral resolution. Eleven targets with curved array must be visualized separately for acceptable axial/lateral resolution. Transverse length of targets located at 6 cm and 10 cm in depth are measured for the evaluation of focal zone. 535 Fig. 4. Sensitivity and functional resolution. 8 mm sized cystic structures are well visualized on the most of ultrasound equipments. Cystic structures clearly demonstrated over 180are counted.

4 Fig. 5. Gray scale and dynamic range. Four or more targets must be clearly visualized over 180among six targets for acceptable gray scale and dynamic range. 536

Table 1. Number of US Equipments on Detection of Dead Zone Targets No. of dead zone targets 30.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 Total No. of US equipments.099.04.02.

5 Table 1. Number of US Equipments on Detection of Dead Zone Targets No. of dead zone targets Total No. of US equipments (%) Table 2. Number of US Equipments on Error in Vertical Measurement Fig. 6. Causes of incongruence. 537

Table 3. Number of US Equipments on Error in Horizontal Measurement Table 4. Number of US Equipments on Lateral/Axial Resolution No. of targets 11 10 9 8 7 6 5 4 3 Total No.

6 Table 3. Number of US Equipments on Error in Horizontal Measurement Table 4. Number of US Equipments on Lateral/Axial Resolution No. of targets Total No. of US equipments (%) Table 5. Number of US Equipments on Focal Zone Rate Focusing rate (%) Total No. of US equipments (%) Table 6. Number of US Equipments on Functional Resolutions Classified by Size and Depth order size 8th 7th 6th 5th 4th 3rd 2nd 1st 8 mm mm mm mm mm

7 Table 7. Number of US Equipments on Gray Scales No. of gray scale Total No. of US equipments (%) Table 8. p-value in Mann-Whitney U Test about Measuring Items of US Phantom Focal Functional Functional Functional Functional Functional Vertical Horizontal zone rate resolution resolution resolution resolution resolution 8 mm 6 mm 4 mm 2 mm 1 mm Asymp.Sig (2-tailed) Table 9. Congruence Rate of Items in US Phantom functional functional functional functional functional Vertical Horizontal Focal zone resolution resolution resolution resolution resolution measurement measurement rate 8 mm 6 mm 4 mm 2 mm 1 mm AUC* AUC* = area under the ROC curve. 539

8 : ,,,,,,. in Gibson NM, Dudley NJ, Griffith K. A computerised quality control testing system for B-mode ultrasound. Ultrasound Med Biol 2001; 27: ATS Laboratories. Test performed. Bridgeport, CT: ATS Laboratories, Inc., ATS Laboratories. Clinical quality assurance phantoms: Multipurpose phantom model 539. Bridgeport, CT: ATS Laboratories, Inc., Alasaarela E, Koivukangas J. Evaluation of image quality of ultrasound scanners in medical diagnostics. J Ultrasound Med 1990; 9: Meuwly JY. Quality control in ultrasonography. Ther Umsch 1997; 54: Madsen EL. Quality assurance for grey-scale imaging. 2000;26 Suppl 1:S48-S50 9. Goodsitt MM, Carson PL, Witt S, Hykes DL, Kofler JM, Jr. Realtime B-mode ultrasound quality control test procedures: Report of AAPM ultrasound task group No. 1. Med Phys 1998;25:

9 Quality Assessment of Ultrasonographic Equipment Using an ATS-539 Multipurpose Phantom 1 Pyo Nyun Kim, M.D., Joo Won Lim, M.D. 2, Hyun Cheol Kim, M.D. 3, Young Cheol Yoon, M.D. 4, Deuk Je Sung, M.D. 5, Min Hoan Moon, M.D. 6, Jeong Sook Kim, M.D. 7, Jong Chan Kim, M.D. 8 1 Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine 2 Department of Radiology, Kyung Hee University Hospital, College of Medicine, Kyung Hee University 3 Department of Radiology, East-west Neo Medical Center, College of Medicine, Kyung Hee University 4 Department of Radiology, Sam Sung Seoul Hospital, Sung Kyunkwan University 5 Department of Radiology, College of Medicine, Korea University 6 Department of Radiology, College of Medicine, Kwandong University 7 Department of Radiology, Dongguk University International Hospital 8 Korea Industry & Technology Research Institute Purpose: To determine the rate of congruence and to standardize assessment of US (ultrasound) phantom images with the use of an ATS-539 multipurpose phantom for US equipment currently utilized in Korea Materials and Methods: US phantom images were scanned with a MHz convex transducer and were digitized by use of an analogue-digital converter. Members of a committee with consent evaluated the US phantom images from 108 types of ultrasound equipment. The dead zone, vertical and horizontal measurement, axial/lateral resolution, focal zone, sensitivity, functional resolution and gray scale/dynamic range were evaluated. Congruence or incongruence of ultrasound equipment was determined based on the results of dead zone, axial/lateral resolution and gray scale/dynamic range measurements. Other factors were evaluated for the possibility as criteria with the use of the Mann-Whitney U test and receiver operator characteristic (ROC) curve analysis. Results: The dead zone, axial/lateral resolution and gray scale/dynamic range were 91.7%, 94.4% and 76.9%, respectively, for suitable US equipment. Considering all three factors, 78 types of ultrasound equipment were passed. The congruence rate of focal zone and functional resolution were 62.4% and 69.3% of the US equipment, respectively. Conclusion: Of the US equipment, 72.2% of the equipment was acceptable based on the dead zone, axial/lateral resolution, and gray scale/dynamic range measurements as determined with the use of an ATS-539 phantom. Focal zone and 8 mm-functional resolution can be useful as a standard in the assessment of a US phantom image. Index words : Ultrasonography Equipment Phantom Quality control Quality assessment Address reprint requests to : Pyo Nyun Kim, M.D., Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, 388-1, Poongnap-dong, Songpa-gu, Seoul , Korea. Tel Fax pnkim@amc.seoul.kr 541

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