193 research outputs found
Reconstruction of panoramic dental Iimages through BĂ©zier function optimization
The authors were grateful to CAPES, CNPq, and FAPESP for their financial support.Computed tomography (CT) and X-ray images have been extensively used as a valuable diagnostic tool in dentistry for surgical planning and treatment. Nowadays, dental cone beam CT has been extensively used in dental clinics. Therefore, it is possible to employ three-dimensional (3D) data from the CT to reconstruct a two-dimensional (2D) panoramic dental image that provides a longitudinal view of the mandibular region of the patient, avoiding an additional exposure to X-ray. In this work, we developed a new automatic method for reconstructing 2D panoramic images of the dental arch based on 3D CT images, using BĂ©zier curves and optimization techniques. The proposed method was applied to five patients, some of them with missing teeth, and smooth panoramic images with good contrast were obtained.info:eu-repo/semantics/publishedVersio
Cone beam CT of the musculoskeletal system : clinical applications
Objectives: The aim of this pictorial review is to illustrate the use of CBCT in a broad spectrum of musculoskeletal disorders and to compare its diagnostic merit with other imaging modalities, such as conventional radiography (CR), Multidetector Computed Tomography (MDCT) and Magnetic Resonance Imaging.
Background: Cone Beam Computed Tomography (CBCT) has been widely used for dental imaging for over two decades.
Discussion: Current CBCT equipment allows use for imaging of various musculoskeletal applications. Because of its low cost and relatively low irradiation, CBCT may have an emergent role in making a more precise diagnosis, assessment of local extent and follow-up of fractures and dislocations of small bones and joints. Due to its exquisite high spatial resolution, CBCT in combination with arthrography may be the preferred technique for detection and local staging of cartilage lesions in small joints. Evaluation of degenerative joint disorders may be facilitated by CBCT compared to CR, particularly in those anatomical areas in which there is much superposition of adjacent bony structures. The use of CBCT in evaluation of osteomyelitis is restricted to detection of sequestrum formation in chronic osteomyelitis. Miscellaneous applications include assessment of (symptomatic) variants, detection and characterization of tumour and tumour-like conditions of bone.
Teaching Points:
Review the spectrum of MSK disorders in which CBCT may be complementary to other imaging techniques.
Compare the advantages and drawbacks of CBCT compared to other imaging techniques.
Define the present and future role of CBCT in musculoskeletal imaging
Oral-3Dv2: 3D Oral Reconstruction from Panoramic X-Ray Imaging with Implicit Neural Representation
3D reconstruction of medical imaging from 2D images has become an
increasingly interesting topic with the development of deep learning models in
recent years. Previous studies in 3D reconstruction from limited X-ray images
mainly rely on learning from paired 2D and 3D images, where the reconstruction
quality relies on the scale and variation of collected data. This has brought
significant challenges in the collection of training data, as only a tiny
fraction of patients take two types of radiation examinations in the same
period. Although simulation from higher-dimension images could solve this
problem, the variance between real and simulated data could bring great
uncertainty at the same time. In oral reconstruction, the situation becomes
more challenging as only a single panoramic X-ray image is available, where
models need to infer the curved shape by prior individual knowledge. To
overcome these limitations, we propose Oral-3Dv2 to solve this cross-dimension
translation problem in dental healthcare by learning solely on projection
information, i.e., the projection image and trajectory of the X-ray tube. Our
model learns to represent the 3D oral structure in an implicit way by mapping
2D coordinates into density values of voxels in the 3D space. To improve
efficiency and effectiveness, we utilize a multi-head model that predicts a
bunch of voxel values in 3D space simultaneously from a 2D coordinate in the
axial plane and the dynamic sampling strategy to refine details of the density
distribution in the reconstruction result. Extensive experiments in simulated
and real data show that our model significantly outperforms existing
state-of-the-art models without learning from paired images or prior individual
knowledge. To the best of our knowledge, this is the first work of a
non-adversarial-learning-based model in 3D radiology reconstruction from a
single panoramic X-ray image
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