Accurate detection of cephalometric landmarks is crucial for orthodontic diagnosis and treatment planning. Current landmark detection methods are mainly divided into heatmap-based and regression-based approaches. However, these methods often rely on parallel computation of multiple models to improve accuracy, significantly increasing the complexity of training and deployment. This paper presented a novel regression method that can simultaneously detect all cephalometric landmarks in high-resolution X-ray images. By leveraging the encoder module of Transformer, a dual-encoder model was designed to achieve coarse-to-fine localization of cephalometric landmarks. The entire model consisted of three main components: a feature extraction module, a reference encoder module, and a fine-tuning encoder module, responsible for feature extraction and fusion of X-ray images, coarse localization of cephalometric landmarks, and fine localization of landmarks, respectively. The model was fully end-to-end differentiable and could learn the intercorrelation relationships between cephalometric landmarks. Experimental results showed that the successful detection rate (SDR) of our algorithm was superior to other existing methods. It attained the highest 2 mm SDR of 89.51% on test set 1 of the ISBI2015 dataset and 90.68% on the test set of the ISBI2023 dataset. Meanwhile, it reduces memory consumption and enhances the model's popularity and applicability, providing more reliable technical support for orthodontic diagnosis and treatment plan formulation.
Cephalometry/methods* ; Humans ; Algorithms ; Anatomic Landmarks/diagnostic imaging* ; Image Processing, Computer-Assisted/methods* ; X-Rays

OBJECTIVE: To explore the anatomical parameters of the cervical uncinate process "inflection point" through cervical CT angiography (CTA) and MRI measurements, offering a reliable and safe anatomical landmark for anterior cervical decompression surgery. METHODS: A retrospective analysis was conducted on the cervical CTA and MRI imaging data of normal adults who met the selection criteria between January 2020 and January 2024. The CTA dataset included 326 cases, with 200 males and 126 females, aged 22-55 years (mean, 46.7 years). The MRI dataset included 300 cases, with 200 males and 100 females, aged 18-55 years (mean, 43.7 years). Based on the CTA data, three-dimensional models of C ₃-C ₇ were constructed, and the following measurements were obtained from the superior view: uncinate process "inflection point" to vertebral artery distance (UIVD), uncinate process tip to vertebral artery distance (UTVD), uncinate process "inflection point" to "inflection point" distance (UID), uncinate process long-axis to sagittal angle (ULSA), and uncinate process "inflection point" to transverse foramen-sagittal angle (UITSA). From the anterior view, the anterior uncinate process to sagittal angle (AUSA) was measured. From the posterior view, the posterior uncinate process to sagittal angle (PUSA) was measured. Based on the MRI data, uncinate process "inflection point" to dural sac distance (UIDD) and dural sac width (DSW) were measured. The trends in measurement parameters of C ₃-C ₇ were observed, and the differences in measurement parameters between genders and between the left and right sides of the same segment were compared, as well as the difference in UID and DSW within the same segment was compared. RESULTS: The measurement parameters from C ₃ to C ₇ in the CTA data showed a general increasing trend, with no significant difference between the left and right sides within the same segment ( P>0.05). The UIVD, UTVD, and UID were greater in males than in females, with significant differences observed in the UIVD and UTVD at C ₃ and C ₆ and UID at C ₃, C ₆, and C ₇ ( P<0.05). The MRI measured DSW showed a general increasing trend from C ₃ to C ₇, and the DSW at C ₆ was greater in females than in males, with a significant difference ( P<0.05). The UIDD showed a gradual decreasing trend, with the smallest value at C ₆. There was no significant difference between males and females or between the left and right sides within the same segment ( P>0.05). The UID was greater than the DSW at C ₃-C ₇, and the differences were significant ( P<0.05). CONCLUSION The uncinate process "inflection point" is a constant anatomical structure located at the anteromedial aspect of the uncinate process tip and laterally to the dural sac. It maintains a certain safe distance from the vertebral artery. As a decompression landmark in anterior cervical spine surgery, it not only ensures surgical safety but also guarantees complete decompression.
Humans ; Adult ; Male ; Female ; Middle Aged ; Retrospective Studies ; Cervical Vertebrae/surgery* ; Magnetic Resonance Imaging ; Decompression, Surgical/methods* ; Young Adult ; Adolescent ; Computed Tomography Angiography ; Imaging, Three-Dimensional ; Vertebral Artery/anatomy & histology* ; Anatomic Landmarks/diagnostic imaging*

OBJECTIVE: To explore an efficient and automatic method for determining the anatomical landmarks of three-dimensional(3D) mandibular data, and to preliminarily evaluate the performance of the method. METHODS: The CT data of 40 patients with normal craniofacial morphology were collected (among them, 30 cases were used to establish the 3D mandibular average model, and 10 cases were used as test datasets to validate the performance of this method in determining the mandibular landmarks), and the 3D mandibular data were reconstructed in Mimics software. Among the 40 cases of mandibular data after the 3D reconstruction, 30 cases that were more similar to the mean value of Chinese mandibular features were selected, and the size of the mandibular data of 30 cases was normalized based on the Procrustes analysis algorithm in MATLAB software. Then, in the Geomagic Wrap software, the 3D mandibular average shape model of the above 30 mandibular data was constructed. Through symmetry processing, curvature sampling, index marking and other processing procedures, a 3D mandible structured template with 18 996 semi-landmarks and 19 indexed mandibular anatomical landmarks were constructed. The open source non-rigid registration algorithm program Meshmonk was used to match the 3D mandible template constructed above with the tested patient's 3D mandible data through non-rigid deformation, and 19 anatomical landmark positions of the patient's 3D mandible data were obtained. The accuracy of the research method was evaluated by comparing the distance error of the landmarks manually marked by stomatological experts with the landmarks marked by the method of this research. RESULTS: The method of this study was applied to the data of 10 patients with normal mandibular morphology. The average distance error of 19 landmarks was 1.42 mm, of which the minimum errors were the apex of the coracoid process [right: (1.01±0.44) mm; left: (0.56±0.14) mm] and maximum errors were the anterior edge of the lowest point of anterior ramus [right: (2.52±0.95) mm; left: (2.57±1.10) mm], the average distance error of the midline landmarks was (1.15±0.60) mm, and the average distance error of the bilateral landmarks was (1.51±0.67) mm. CONCLUSION The automatic determination method of 3D mandibular anatomical landmarks based on 3D mandibular average shape model and non-rigid registration algorithm established in this study can effectively improve the efficiency of automatic labeling of 3D mandibular data features. The automatic determination of anatomical landmarks can basically meet the needs of oral clinical applications, and the labeling effect of deformed mandible data needs to be further tested.
Humans ; Imaging, Three-Dimensional/methods* ; Mandible/diagnostic imaging* ; Software ; Algorithms ; Anatomic Landmarks/anatomy & histology*

OBJECTIVETo assess the safety and the accuracy of surgical navigation technology in the resection of severe ankylosis of the mandibular condyle with the middle cranial fossa.

METHODSThe CT scan data was transferred to a Windows-based computer workstation, and the patient' s individual anatomy was assessed in multiplanar views at the workstation. In the operation, the patient and the virtual image were matched by individual registration with the reference points which were set on the skull bone surface and the teeth. Then the real time navigation can be performed.

RESULTSThe acquisition of the data sets was uncomplicated, and image quality was sufficient to assess the operative result in three cases. The operations were performed successfully with the guidance of real-time navigation. The application of surgical navigation have enhanced the safety and the accuracy of the surgery for bony ankylosis of temporomandibular joint.

CONCLUSIONSThe application of surgical navigation can improve the accuracy and safety of surgical excision of the ankylosed skull base tissue.

Anatomic Landmarks ; anatomy & histology ; Ankylosis ; surgery ; Humans ; Skull ; diagnostic imaging ; surgery ; Surgery, Computer-Assisted ; methods ; Temporomandibular Joint ; surgery ; Temporomandibular Joint Disorders ; surgery ; Tomography, X-Ray Computed

OBJECTIVE: To evaluate the value of spinal and paraspinal anatomic markers in both the diagnosis of lumbosacral transitional vertebrae (LSTVs) and identification of vertebral levels on lumbar MRI. MATERIALS AND METHODS: Lumbar MRI from 1049 adult patients were studied. By comparing with the whole-spine localizer, the diagnostic errors in numbering vertebral segments on lumbar MRI were evaluated. The morphology of S1-2 disc, L5 and S1 body, and lumbar spinous processes (SPs) were evaluated by using sagittal MRI. The positions of right renal artery (RRA), superior mesenteric artery, aortic bifurcation (AB) and conus medullaris (CM) were described. RESULTS: The diagnostic error for evaluation of vertebral segmentation on lumbar MRI alone was 14.1%. In lumbarization, all patients revealed a well-formed S1-2 disc with squared S1 body. A rhombus-shaped L5 body in sacralization and a rectangular-shaped S1 body in lumbarization were found. The L3 had the longest SP. The most common sites of spinal and paraspinal structures were: RRA at L1 body (53.6%) and L1-2 disc (34.1%), superior mesenteric artery at L1 body (55.1%) and T12-L1 disc (31.6%), and AB at L4 body (71.1%). CM had variable locations, changing from the T12-L1 disc to L2 body. They were located at higher sacralization and lower lumbarization. CONCLUSION: The spinal morphologic features and locations of the spinal and paraspinal structures on lumbar MRI are not completely reliable for the diagnosis of LSTVs and identification on the vertebral levels.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Anatomic Landmarks/*anatomy & histology ; Aorta, Abdominal/anatomy & histology ; Diagnostic Errors ; Female ; Humans ; Intervertebral Disc/anatomy & histology ; Lumbar Vertebrae/*anatomy & histology ; Lumbosacral Region ; Magnetic Resonance Imaging ; Male ; Mesenteric Artery, Superior/anatomy & histology ; Middle Aged ; Renal Artery/anatomy & histology ; Reproducibility of Results ; Sacrum/*anatomy & histology ; Spinal Cord/anatomy & histology ; Spine ; Young Adult

OBJECTIVETo present a method of quantitative diagnosis of craniofacial skeleton deformities based on three-dimensional computed tomography (3D CT).

METHODS20 cases with facial asymmetric deformities underwent 3D CT and the 3D images were reconstructed by Mimics 10.0 (Belgium). Anatomical landmarks were located and the coordinate of the landmarks obtained. Axial images of 1 patient with Romberg disease was used as representative case. The differences in the distance between the right landmarks and the left were calculated and analyzed.

RESULTSThe measurement results were not significantly different between two stages with an interval of 4 weeks ( P > 0.05), showing a reproducible resutls. The deviation of landmarks at facial midline increased gradually from upward to downward, reaching (2.63 +/- 0.54) mm at menton point. Paired landmarks showed asymmetry in three dimensions, especially gonion point on the left side, which was deviated 10.21 mm inward, 9.26 mm forward, 6.30 mm upward, compared to the opposite side.

CONCLUSIONSThe method of 3D CT quantitative analysis can provide precise information in the diagnosis and treatment planning of facial asymmetry deformity.

Anatomic Landmarks ; diagnostic imaging ; Cephalometry ; Craniofacial Abnormalities ; diagnostic imaging ; Facial Asymmetry ; diagnostic imaging ; Humans ; Imaging, Three-Dimensional ; methods ; Tomography, X-Ray Computed ; methods

Anatomic Landmarks ; diagnostic imaging ; Cone-Beam Computed Tomography ; methods ; Esophageal Neoplasms ; diagnostic imaging ; pathology ; radiotherapy ; Esophagus ; diagnostic imaging ; pathology ; Fiducial Markers ; Four-Dimensional Computed Tomography ; methods ; Humans ; Image Processing, Computer-Assisted ; methods ; Movement ; Radiotherapy Planning, Computer-Assisted ; methods ; Radiotherapy, Conformal ; methods ; Radiotherapy, Intensity-Modulated ; methods ; Respiration