Software for automated application of a reference-based method for<i>a posteriori</i>determination of the effective radiographic imaging geometry

Schulze, Ralf; Weinheimer, Oliver; Brüllmann, Dan; Roder, Fredrick L.; dʼHoedt, B; Schoemer, Elmar

doi:10.1259/dmfr/56357032

Cited by 6 publications

(3 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A few authors attempted to describe methods to assess the parameters of projection geometry. For example, Lehmann and Schropp provided a novel representation of sphere projection and an exhaustive analysis of the extrinsic features used 2 ; further, great progress was made by Schulze, who developed a software providing important information for accurate image recording 14 and an analytical algorithm capable of determining localization and orientation of a cylindrical dental implant in three-dimensional space from a single radiographic projection. 15 The author reduced the six possible df to five (three translational and two rotational), because the one related to the implant length axis appeared hidden.…”

Section: Discussionmentioning

confidence: 99%

Pose determination of a blade implant in three dimensions from a single two-dimensional radiograph

Toti

Barone

Marconcini

et al. 2018

Dentomaxillofacial Radiology

View full text Add to dashboard Cite

The aim of the study was to introduce a mathematical method to estimate the correct pose of a blade by evaluating the radiographic features obtained from a single two-dimensional image. Blade-form implant bed preparation was performed using the piezosurgery device, and placement was attained with the use of magnetic mallet. The pose determination of the blade was described by means of three consecutive rotations defined by three angles of orientation (triplet φ, θ and ψ). Retrospective analysis on periapical radiographs was performed. This method was used to compare implant (axial length along the marker, i.e. the implant structure) vs angular correction factor (a trigonometric function of the triplet). The accuracy of the method was tested by generating two-dimensional radiographic simulations of the blades, which were then compared with the images of the implants as appearing on the real radiographs. Two patients had to be excluded from further evaluation because the values of the estimated pose angles showed a too-wide range to be effective for a good standardization of serial radiographs: intrapatient range from baseline to 1-year survey was > of a threshold determined by the clinicians (30°). The linear dependence between implant (CF°) and angular correction factor (CF^) was estimated by a robust linear regression, yielding the following coefficients: slope, 0.908; intercept, −0.092; and coefficient of determination, 0.924. The absolute error in accuracy was −0.29 ± 4.35, 0.23 ± 3.81 and 0.64 ± 1.18°, respectively, for the angles φ, θ and ψ. The present theoretical and experimental study established the possibility of determining, a posteriori, a unique triplet of angles (φ, θ and ψ) which described the pose of a blade upon a single two-dimensional radiograph, and of suggesting a method to detect cases in which the standardized geometric projection failed. The angular correction of the bone level yielded results very close to those obtained with an internal marker related to the implant length.

show abstract

Section: Discussionmentioning

confidence: 99%

Pose determination of a blade implant in three dimensions from a single two-dimensional radiograph

Toti

Barone

Marconcini

et al. 2018

Dentomaxillofacial Radiology

View full text Add to dashboard Cite

show abstract

“…Some let the coordinate system be located external to the relevant structures using at least three radiopaque spheres of known dimension [4][5][6]; one of them later had been quite successful in achieving a solution to the descriptions of the geometric structure about the position of the cylindrical dental implant in space [12]; he designed the system of the rigid object to be as compact as possible while describing translational and rotational vector graphics. However, the degree of freedom related to the rotation along the main axis of the dental implant remained unknown.…”

Section: Discussionmentioning

confidence: 99%

“…The determination of the three-dimensional position and orientation of known objects from single perspective projections were initially proposed by Hoffmann and Esthappan with a priori knowledge of positions of the specific markers [4]. Generally, external markers (alone or in combination with a holding device) were and are employed to allow for an accurate estimate a posteriori of the object's position and orientation, thereby providing both the referral points in space (set of three radiopaque ball bearings or spheres) and the known dimensions of the object being analyzed [5,6].…”

Section: Introductionmentioning

confidence: 99%

Standardization of Three-Dimensional Pose of Cylindrical Implants From Intraoral Radiographs

Cosola¹,

Toti²,

Peñarrocha‐Diago³

et al. 2020

Preprint

View full text Add to dashboard Cite

BackgroundTo introduce a theoretical solution to a posteriori describe the pose of a cylindrical dental fixture as appearing on radiographs; to experimentally validate the method described.MethodsThe pose of a conventional dental implant was described by a triplet of angles (phi-pitch, theta-roll, and psi-yaw) which was calculated throughout vector analysis. Radiographic- and simulated-image obtained with an algorithm were compared to test effectiveness, reproducibility, and accuracy of the method. The length of the dental implant as appearing on the simulated image was calculated by the trigonometric function and then compared with real length as it appeared on a two-dimensional radiograph. ResultsTwenty radiographs were analyzed for the present in silico and retrospective study. Among 40 fittings, 37 resulted as resolved with residuals ≤1mm. Similar results were obtained for radiographic and simulated implants with absolute errors of -1.1±3.9° for phi; -0.9±4.1° for theta; 0±1.1° for psi. The real and simulated length of the implants appeared to be heavily correlated. Linear dependence was verified by the results of the robust linear regression: 0.9757 (slope), +0.1344mm (intercept), and an adjusted coefficient of determination of 0.9054.ConclusionsThe method allowed clinicians to calculate, a posteriori, a single real triplet of angles (phi,theta,psi) by analyzing a two-dimensional radiograph and to identify cases where standardization of repeated intraoral radiographies was not achieved. The a posteriori standardization of two-dimensional radiographs could allowed the clinicians to minimize the patient's exposure to ionizing radiations for the measurement of marginal bone levels around dental implants.Trial registrationThe Human Investigation Committee (IRB) of University of Pisa approved present retrospective data analysis (Ethical Approval Form 2626/2008 Protocol Number 58183)

show abstract

Ex vivo radiographic tooth length measurements with the reference sphere method (RSM)

et al. 2009

View full text Add to dashboard Cite

A reference-based radiographic "reference sphere method" (RSM) for accurate length measurements in (dental) projection radiographs for the assessment of tooth length in dry human mandible sections is evaluated. RSM determines the depth coordinates of reference spheres placed in the object plane from the elliptical distortion of their shadows. Two segments (one canine and one molar) of dry human mandibles were exposed 95 times at different angulations (0-40°) on a dental charge-coupled device receptor. Three steel spheres (diameters d (1) = 2.00 mm, d (2) = 3.00 mm) were attached roughly coplanar with the tooth's main axis. Radiographs were assessed once by visual inspection plus manual landmark identification with a mouse-driven cursor. The results were compared to the true tooth length assessed after extraction and to a conventional method (C), i.e., the rule of proportion based on magnification of the sphere shadows. Mean relative length error was 2.28% (d (1)) and 0.46% (d (2)) for RSM and -13.58% (d (1)) and -9.90% (d (2)) for C. For both methods, length errors were significantly (p < 0.0001) correlated with the inclination relative to the receptor. RSM allows for complete a posteriori determination of the imaging geometry under the assumption of a known source-to-receptor distance. One specific application is foreshortening correction of objects coplanar with the reference spheres. Remaining errors are mainly due to incorrect landmark definition. In our setup, these were exaggerated by the visual/manual image-evaluation process. Automated image analysis has been shown for similar tasks to minimize these errors considerably.

show abstract

Software for automated application of a reference-based method fora posterioridetermination of the effective radiographic imaging geometry

Abstract: The software provides information fundamentally important for the image formation and geometric image registration, which is a crucial step for three-dimensional reconstruction from > or =2 two-dimensional views.

Cited by 6 publications

References 16 publications

Pose determination of a blade implant in three dimensions from a single two-dimensional radiograph

Pose determination of a blade implant in three dimensions from a single two-dimensional radiograph

Standardization of Three-Dimensional Pose of Cylindrical Implants From Intraoral Radiographs

Ex vivo radiographic tooth length measurements with the reference sphere method (RSM)

Contact Info

Product

Resources

About