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Evaluation of a dental subtraction radiography system
Author(s) -
Ellwood R. P.,
Davies R. M.,
Worthington H. V.
Publication year - 1997
Publication title -
journal of periodontal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.31
H-Index - 83
eISSN - 1600-0765
pISSN - 0022-3484
DOI - 10.1111/j.1600-0765.1997.tb00530.x
Subject(s) - subtraction , radiography , nuclear medicine , image subtraction , computer vision , artificial intelligence , mathematics , molar , image processing , medicine , biomedical engineering , computer science , dentistry , image (mathematics) , radiology , binary image , arithmetic
The aim of this in vitro study was to evaluate the ability of a dental subtraction radiography system to quantitatively detect differences in density between radiographic image pairs. Four periapical radiographs were taken of the upper first permanent molars on 5 human skulls using the Digora radiographic imaging system. The 4 images were a “baseline” image and 3 containing test objects consisting of either 0.5, 1 or 2 mm thick aluminium cylinders, 2.5 mm in diameter. Semi‐automated image processing software was used to “warp” the 3 images with test objects into the same geometric/density registration as the corresponding baseline image using a process called patch minimization. “Difference” images were then produced and their contrast stretched. For regions of interest, with and without test objects present, the difference in density between the baseline and “test object” images was calculated using a reference aluminium step wedge. The test objects were clearly visible in all the “difference” images. The mean difference between the actual and estimated volume of the test object was 0.31 (95% CI [−0.55, 1.17]) mm 3 Al. There was a strong association (r=0.83) between the actual and estimated aluminium volumes. It is concluded that this system provides adequate precision for clinical evaluation.