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An evaluation of cellular neural networks for the automatic identification of cephalometric landmarks on digital images.

Leonardi R, Giordano D, Maiorana F - J. Biomed. Biotechnol. (2009)

Bottom Line: Differences in the mean errors of automatic and manual landmarking were compared with a 1-way analysis of variance.Furthermore, only few of these differences were statistically significant, but differences were so small to be in most instances clinically meaningless.Therefore the use of X-ray files with respect to scanned X-ray improved landmark accuracy of automatic detection.

View Article: PubMed Central - PubMed

Affiliation: Istituto di II Clinica Odontoiatrica, Policlinico Città Universitaria, Catania, Italy. rleonard@unict.it

ABSTRACT
Several efforts have been made to completely automate cephalometric analysis by automatic landmark search. However, accuracy obtained was worse than manual identification in every study. The analogue-to-digital conversion of X-ray has been claimed to be the main problem. Therefore the aim of this investigation was to evaluate the accuracy of the Cellular Neural Networks approach for automatic location of cephalometric landmarks on softcopy of direct digital cephalometric X-rays. Forty-one, direct-digital lateral cephalometric radiographs were obtained by a Siemens Orthophos DS Ceph and were used in this study and 10 landmarks (N, A Point, Ba, Po, Pt, B Point, Pg, PM, UIE, LIE) were the object of automatic landmark identification. The mean errors and standard deviations from the best estimate of cephalometric points were calculated for each landmark. Differences in the mean errors of automatic and manual landmarking were compared with a 1-way analysis of variance. The analyses indicated that the differences were very small, and they were found at most within 0.59 mm. Furthermore, only few of these differences were statistically significant, but differences were so small to be in most instances clinically meaningless. Therefore the use of X-ray files with respect to scanned X-ray improved landmark accuracy of automatic detection. Investigations on softcopy of digital cephalometric X-rays, to search more landmarks in order to enable a complete automatic cephalometric analysis, are strongly encouraged.

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Three cases of automatic location of Porion. In red is the expert landmark, and in green is the automatic landmark.
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Related In: Results  -  Collection


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fig14: Three cases of automatic location of Porion. In red is the expert landmark, and in green is the automatic landmark.

Mentions: If the parameters of the spots do not satisfy anatomical constraints (i.e., area, or width, or height) or the located landmark is too far from the center of the spot where it lies the same template with an increased bias until the spots and the located landmark satisfy the anatomical constraints, the algorithm is able to correctly find the Porion landmark even if in the X-ray both the auditory conducts are visible. In this case the landmark is computed as the middle point between the two auditory conducts. Figure 14 shows the location of the automatically detected Porion (in green) and the expert location (in red) in three different cases.


An evaluation of cellular neural networks for the automatic identification of cephalometric landmarks on digital images.

Leonardi R, Giordano D, Maiorana F - J. Biomed. Biotechnol. (2009)

Three cases of automatic location of Porion. In red is the expert landmark, and in green is the automatic landmark.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2742650&req=5

fig14: Three cases of automatic location of Porion. In red is the expert landmark, and in green is the automatic landmark.
Mentions: If the parameters of the spots do not satisfy anatomical constraints (i.e., area, or width, or height) or the located landmark is too far from the center of the spot where it lies the same template with an increased bias until the spots and the located landmark satisfy the anatomical constraints, the algorithm is able to correctly find the Porion landmark even if in the X-ray both the auditory conducts are visible. In this case the landmark is computed as the middle point between the two auditory conducts. Figure 14 shows the location of the automatically detected Porion (in green) and the expert location (in red) in three different cases.

Bottom Line: Differences in the mean errors of automatic and manual landmarking were compared with a 1-way analysis of variance.Furthermore, only few of these differences were statistically significant, but differences were so small to be in most instances clinically meaningless.Therefore the use of X-ray files with respect to scanned X-ray improved landmark accuracy of automatic detection.

View Article: PubMed Central - PubMed

Affiliation: Istituto di II Clinica Odontoiatrica, Policlinico Città Universitaria, Catania, Italy. rleonard@unict.it

ABSTRACT
Several efforts have been made to completely automate cephalometric analysis by automatic landmark search. However, accuracy obtained was worse than manual identification in every study. The analogue-to-digital conversion of X-ray has been claimed to be the main problem. Therefore the aim of this investigation was to evaluate the accuracy of the Cellular Neural Networks approach for automatic location of cephalometric landmarks on softcopy of direct digital cephalometric X-rays. Forty-one, direct-digital lateral cephalometric radiographs were obtained by a Siemens Orthophos DS Ceph and were used in this study and 10 landmarks (N, A Point, Ba, Po, Pt, B Point, Pg, PM, UIE, LIE) were the object of automatic landmark identification. The mean errors and standard deviations from the best estimate of cephalometric points were calculated for each landmark. Differences in the mean errors of automatic and manual landmarking were compared with a 1-way analysis of variance. The analyses indicated that the differences were very small, and they were found at most within 0.59 mm. Furthermore, only few of these differences were statistically significant, but differences were so small to be in most instances clinically meaningless. Therefore the use of X-ray files with respect to scanned X-ray improved landmark accuracy of automatic detection. Investigations on softcopy of digital cephalometric X-rays, to search more landmarks in order to enable a complete automatic cephalometric analysis, are strongly encouraged.

Show MeSH