Journal of Digital Imaging

, Volume 24, Issue 2, pp 331–338 | Cite as

Influence of Image Metrics When Assessing Image Quality from a Test Object in Cardiac X-ray Systems

  • Eliseo Vano
  • Carlos Ubeda
  • Bernhard Geiger
  • Luis C. Martinez
  • Stephen Balter


Modern fluoroscopic systems used for invasive cardiology typically acquire digital images in a 1,024 × 1,024 × 12 bits. These images are maintained in the original format while they remain on the imaging system itself. However, images are usually stored using a reduced 512 × 512 × 8-bits format. This paper presents a method for digital analysis of test objects images. The results obtained using image-intensifier and flat-detector systems are given for the original and reduced matrices. Images were acquired using a test object (TO) and a range of polymethyl methacrylate (PMMA) thicknesses from 4 to 28 cm. Adult patient protocols were evaluated for 16–28 cm of PMMA using the image-intensifier system. Pediatric protocols were evaluated for 4–16 cm of PMMA using the flat-detector system. The TO contains disks of various thicknesses to evaluate low contrast sensitivity and a bar pattern to evaluate high-contrast spatial resolution (HCSR). All available fluoroscopic and cine modes were evaluated. Entrance surface air kerma was also measured. Signal-to-noise ratio (SNR) was evaluated using regions of interest (ROI). HCSR was evaluated by comparing the statistical analysis of a ROI placed over the image of the bar pattern against a reference ROI. For both systems, an improvement of approximately 20% was observed for the SNR on the reduced matrices. However, the HCSR parameter was substantially lower in the reduced metrics. Cardiologists should consider the clinical influence of reduced spatial resolution when using the archived images.

Key words

Image quality test object matrix size catheterization cardiology 



One of the authors (EV) acknowledges the support of the Spanish grant FIS2006-08186 (Ministry of Science and Innovation).


  1. 1.
    Erickson BJ: Irreversible Compression of Medical Images. White Paper-Irreversible Compression of Medical Images. 2000. Available at: Accessed 29 August 2009
  2. 2.
    Silber S, Dörr R, Zindler G, Mühling H, Diebel T: Impact of various compression rates on interpretation of digital coronary angiograms. Int J Cardiol 60:195–200, 1997PubMedCrossRefGoogle Scholar
  3. 3.
    Brennecke R, Bürgel U, Simon R, Rippin G, Fritsch HP, Becker T, Nissen SE: American College of Cardiology European Society of Cardiology/International Study of Angiographic Data Compression Phase III: measurement of image quality differences at varying levels of data compression. J Am Coll Cardiol 35:1388–1397, 2000PubMedCrossRefGoogle Scholar
  4. 4.
    Kerensky RA, Cusma JT, Kubilis P, Simon R, Bashore TM, Hirshfeld Jr, JW, Holmes Jr, DR, Pepine CJ, Nissen SE: American College of Cardiology/European Society of Cardiology International Study of Angiographic Data Compression Phase I: the effect of lossy data compression on recognition of diagnostic features in digital coronary angiography. J Am Coll Cardiol 35:1370–1379, 2000PubMedCrossRefGoogle Scholar
  5. 5.
    Nissen SE, Hirshfeld Jr, JW, Simon R: Introduction and background: the International Angiographic Compression Study. J Am Coll Cardiol 35:1367–1369, 2000PubMedCrossRefGoogle Scholar
  6. 6.
    Vano E, Geiger B, Schreiner A, Back C, Beissel J: Dynamic flat panel detector versus image intensifier in cardiac imaging: dose and image quality. Phys Med Biol 50:5731–5742, 2005PubMedCrossRefGoogle Scholar
  7. 7.
    Martinez LC, Vano E, Gutierrez F, Rodriguez C, Gilarranz R, Manzanas MJ: Patient doses from fluoroscopically guided cardiac procedures in pediatrics. Phys Med Biol 52:4749–4759, 2007PubMedCrossRefGoogle Scholar
  8. 8.
    ICRU International Commission on Radiological Units and Measurements: Patient dosimetry for x rays used in medical imaging ICRU Report 74 (J. ICRU 5 (2)), 2005Google Scholar
  9. 9.
    Rassow J, Schmaltz AA, Hentrich F, Streffer C: Effective doses to patients from paediatric cardiac catheterization. Br J Radiol 73:172–183, 2000PubMedGoogle Scholar
  10. 10.
    Gagne RM, Boswell JS, Myers KJ: Signal detectability in digital radiography. spatial domain figures of merit. Med Phys 30:2180–2189, 2003PubMedCrossRefGoogle Scholar
  11. 11.
    Muhogora WE, Devetti A, Padovani R, Msaki P, Bonutti F: Application of European protocol in the evaluation of contrast-to-noise ratio and mean glandular dose for two digital mammography systems. Radiat Prot Dosim 129:231–236, 2008CrossRefGoogle Scholar

Copyright information

© Society for Imaging Informatics in Medicine 2010

Authors and Affiliations

  • Eliseo Vano
    • 1
  • Carlos Ubeda
    • 2
  • Bernhard Geiger
    • 3
  • Luis C. Martinez
    • 4
  • Stephen Balter
    • 5
  1. 1.Radiology DepartmentComplutense University and San Carlos HospitalMadridSpain
  2. 2.Clinical Sciences Department, Faculty of the Science of HealthTarapaca UniversityAricaChile
  3. 3.Siemens AG, Healthcare SectorForchheimGermany
  4. 4.Medical Physics and Radiation Protection Service12 de Octubre University HospitalMadridSpain
  5. 5.Columbia University Medical CenterNew YorkUSA

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