A Werrmann

University of Leipzig , Leipzig, Saxony, Germany

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Publications (5)4.64 Total impact

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    ABSTRACT: In human medical imaging, the performance of the monitor used for image reporting has a substantial impact on the diagnostic performance of the entire digital system. Our purpose was to compare the display quality of different monitors used in veterinary practice. Two medical-grade gray scale monitors (one cathode-ray tube [CRT], one liquid crystal display [LCD]) and two standard consumer-grade color monitors (one CRT, one LCD) were compared in the ability to display anatomic structures in cats. Radiographs of the stifle joint and the thorax of 30 normal domestic shorthair cats were acquired by use of a storage phosphor system. Two anatomic features of the stifle joint and five anatomic structures of the thorax were evaluated. The two medical-grade monitors had superior display quality compared with standard PC monitors. No differences were seen between the monochrome monitors. In comparison with the color CRT, the ratings of the color LCD were significantly worse. The ranking order was uniform for both the region and the criteria investigated. Differences in monitor luminance, bit depth, and screen size were presumed to be the reasons for the observed varying performance. The observed differences between monitors place an emphasis on the need for guidelines defining minimum requirements for the acceptance of monitors and for quality control in veterinary radiography.
    Veterinary Radiology &amp Ultrasound 01/2010; 52(1):1-9. · 1.41 Impact Factor
  • Rofo-fortschritte Auf Dem Gebiet Der Rontgenstrahlen Und Der Bildgebenden Verfahren - ROFO-FORTSCHR RONTGENSTRAHL. 01/2010; 182.
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    ABSTRACT: Objective: The aim of the study was to compare the image quality of radiographs obtained with a storage phosphor (SP) system and a flat-panel detector (FD). Furthermore, the influence of different exposure settings was investigated. Material and methods: In a prospective study a series of lateral thoracic radiographs of 45 normal cats were acquired by use of a standard SP-system and an opto-direct FD. From each animal four radiographs were taken with exposure settings adjusted to achieve sensitivity (S)-values of the system-specific dose indicator of S180 and S360. In a blind study, five observers rated the presentation of anatomical structures (trachea, cranial lung field, sternum, cardiac silhouette, caudal thoracic field) by use of a four-point scale (1 - excellent; 4 - insufficient). Results: Independent of the detector-type and the exposure level applied the mean values of the ratings of the respective image criteria ranged from 1.14 to 1.67. In both systems higher doses related to better rating results. While comparing the detectors on the basis of identical exposure settings the FD demonstrated superior performance. Conclusion and clinical relevance: At the dose levels investigated both detectors reveal an image quality sufficient for the depiction of subtle, low-contrast thoracic structures in cats. Therefore, the detectors can be recommended for practical use in small animal radiology. In both systems a dose reduction of 50% in comparison to the original level (S180) is possible without a substantial loss of information. Because of the superior quantum efficiency the dose saving potential of the FD might be even higher. Alternatively, the higher dose efficiency can be utilised to improve image quality in comparison to the SP-system with identical exposure settings.
    Tierärztliche Praxis. Ausgabe K, Kleintiere/Heimtiere 01/2010; 38(6):355-66. · 0.47 Impact Factor
  • Rofo-fortschritte Auf Dem Gebiet Der Rontgenstrahlen Und Der Bildgebenden Verfahren - ROFO-FORTSCHR RONTGENSTRAHL. 01/2010; 182(02):122-132.
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    ABSTRACT: Is the image quality of thoracic radiographs of cats obtained with a needle-based storage phosphor (NIP) system superior to conventional (PIP) storage phosphor radiography? Is it possible to decrease the mAs by 50 % with the NIP system without significant loss of information? From each of the 20 animals, three lateral radiographs were acquired. The assessment of the exposure level was based on the generated lgM-values. Images were acquired 1. with the NIP system and exposure settings equivalent to an lgM of 1.9, 2. with the PIP system and identical settings, and 3. with the NIP system and 50 % of the mAs. Six blinded readers used a 5-step scale to assess the reproducibility of five anatomical structures and image noise sensation. Data were analysed using Visual Grading Characteristics Analysis (VGC). While applying identical exposure values the NIP system for all features revealed superior ratings to those of the PIP system (AUC (VGC) values ranged from 0.81 for "cardiac silhouette" to 0.92 for "trachea"). Even when reducing mAs by 50 % in the NIP images all features were rated better compared with the PIP images and original settings (AUC (VGC) values ranged from 0.60 for "cardiac silhouette" to 0.74 for "trachea" and "caudal thoracic field"). The NIP system demonstrates clearly better image quality compared to the reference PIP system. A dose reduction of 50 % seems to be possible without relevant detraction from image quality. The results obtained in the animal model are valid for simulating conditions in neonatal radiological practise.
    RöFo - Fortschritte auf dem Gebiet der R 10/2009; 182(2):122-32. · 2.76 Impact Factor