Three dimensional CT reconstruction: a comparison between 2D, 3D CT and original anatomical structures

Evaluation of photogrammetry for medical application in cardiology

Background: In the field of medicine, photogrammetry has played for long time a marginal role due to the significant amount of work required that made it impractical for an extended medical use. Developments in digital photogrammetry occurred in the recent years, that have steadily increased the interest and application of this technique. The present study aims to compare photogrammetry reconstruction of heart with computed tomography (CT) as a reference. Methods: The photogrammetric reconstructions of digital images from ECG imaging derived images were performed. In particular, the ventricles of 15 patients with Brugada syndrome were reconstructed by using the free Zephyr Lite software. In order to evaluate the accuracy of the technique, measurements on the reconstructions were compared to patient-specific CT scan imported in ECG imaging software UZBCIT. Result: The results showed that digital photogrammetry in the context of ventricle reconstruction is feasible. The photogrammetric derived measurements of ventricles were not statistically different from CT scan measurements. Furthermore, the analysis showed high correlation of photogrammetry reconstructions with CT scan and a correlation coefficient close to 1. Conclusion: It is possible to reproduce digital objects by photogrammetry if the process described in this study is performed. The reconstruction of the ventricles from CT scan was very close to the values of the respective photogrammetric reconstruction.

Correlation of radiomorphometric indices of the mandible and mandibular angle fractures

This study assessed the correlation of radiomorphometric indices of the mandible and mandibular angle fractures (MAFs) in an Iranian population. This retrospective study was conducted on 3D computed tomography (CT) scans of 118 patients between 18 to 60 years. The images were divided into two groups with MAFs and other types of mandibular fractures (non-MAF). The gonial angle, ramus height, condylar neck width, minimum ramus width, and mandibular length were all measured using MARCO PACS software. Age, gender, and presence and eruption status of third molar at the fracture side were all recorded. The correlation between these parameters and MAF was analyzed using R software (alpha = 0.05). Of all patients, 41 samples had MAF. The two groups were not significantly different regarding the mean age and gender (P > 0.05). The mean size of gonial angle and ramus height in the MAF group were significantly larger, and smaller than the corresponding values in the non-MAF group, respectively (P < 0.001). The median minimum ramus width in the MAF group was significantly smaller than that in the non-MAF group (P = 0.001). Patients with a large gonial angle had 6.6 times higher odds of MAF compared with other fracture types (P = 0.046). Condylar neck width, mandibular length, and erupted third molars had no significant correlation with type of fracture. Presence of impacted third molar increased the odds of MAF by 5.55 times.

Patients with a large gonial angle, short ramus height, minimum ramus width, and impacted third molar are more susceptible to MAF. Surgeons can use these indices to predict the risk of MAF in trauma patients with such facial characteristics, and make a diagnosis by radiographic modalities.

Application Value of the CT Scan 3D Reconstruction Technique in Maxillofacial Fracture Patients

Purpose The aim of the study was to explore the application value of computerized tomography (CT) scan 3D reconstruction technology in maxillofacial fracture patients. Methods A total of 80 maxillofacial fracture patients who underwent surgical treatment in Shijiazhuang People's Hospital from January 2019 to January 2020 were enrolled. All of them received 128-slice spiral CT  scans before surgery, and the images were subjected to multiplanar reconstruction (MRP) and volume reconstruction (VR). Results A total of 181 fractures were found in 80 patients with maxillofacial fractures. The detection rates of axial CT, MRP, and VR were 77.90% (141/181), 93.92% (170/181), and 97.79% (177/181), respectively. The detection rates of the four inspection methods were statistically different. Taking the findings of surgical anatomy as the gold standard, the sensitivity of MRP and VR for the diagnosis of maxillofacial fractures was 90.06% (163/170) and 95.56% (174/177), with no significant difference. Conclusion CT scan 3D reconstruction technology has a high application value in the clinical diagnosis and treatment of maxillofacial fracture patients.

Accuracy of external measurements of 3-dimensional (3D) printed biomodels of the canine radius used in an in-hospital setting

The objective of this study was to determine if biomodels printed on a fused deposition modeling (FDM) device from computed tomography (CT) data are accurate by comparing external measurements to the native bone, considering that the clinical usefulness of the printed biomodels in an in-hospital setting depends on their verified accuracy and consistency. Using canine cadaveric radii previously stripped of all soft tissues, 7 parameters of the actual bone and the 3-dimensional (3D) printed biomodels were measured and compared to determine how accurately the models represent the cadaveric bone. A total of 28 canine radii were collected, in which the landmarks for measurements were established. Radiographs were then taken to determine the frontal center of rotation of angulation (CORA) and CT scans were carried out. Finally, a 3D virtual reconstruction was done and converted into a stereolithography (STL) format file, from which 2 biomodels were printed per bone. Measurements for biomodels were compared for equivalence to cadaveric measurements. For the 7 measured parameters, the mean difference between biomodel and cadaveric parameters ranged from an increase of +0.66% in cranial-caudal proximal (CrCdP)-CORA to a decrease of -1.32% in distal width of the radius. For all 7 measured parameters, measurements for biomodels were statistically equivalent to their corresponding cadaveric bone (P < 0.001). The 7 measured parameters in the 3D models printed with an FDM device were not significantly different than those in the original bone. In fact, these measurements closely approximated original bone measurements (within 1.5%); therefore, validating their application in future presurgical planning for various orthopedic procedures.

An Evaluation of Dental Crowding in Relation to the Mesiodistal Crown Widths and Arch Dimensions in Southern Indian Population

Introduction

With the advancement in imaging technology, 3D dental computed tomography plays a very significant role in orthodontic treatment and diagnosis.

Aim

To evaluate dental crowding in relation to the mesiodistal crown widths and arch dimensions and also to determine the differences of dental crowding among males and females, in Southern Indian population.

Materials and Methods

A total of 132 subjects were divided into two groups: crowded and non-crowded, each comprising 66 subjects (33 males and 33 females), aged between 15 and 35 years, who were referred for computed tomography scan of brain to the radiology department, were selected. During the scan both the jaws were included in the image. The 2D images were converted to 3D images using volume rendering software. By using measurement tool, individual and collective mesiodistal crown widths of canine, first and second premolar and first molar and arch perimeter of both the maxillary and mandibular jaws were measured.

Results

When both the gender were considered, the mesiodistal crown widths and arch perimeter were statistically significant for dental crowding in both mandibular jaw (p-value=0.001 for both mesiodistal crown width and arch perimeter) and maxillary jaw (p-value=0.016 for mesiodistal crown width and 0.002 for arch perimeter). However, when analysed separately, in males the mesiodistal crown widths and arch perimeter were statistically significant for dental crowding in both mandibular jaw (p-value=0.001 for mesiodistal crown width and 0.002 for arch perimeter) and maxillary jaw (p-value=0.002 for mesiodistal crown width and 0.001 for arch perimeter) but in females it was not statistically significant in any jaw (p-value=0.7 for mesiodistal crown width and 0.06 for arch perimeter in mandibular jaw and p-value=0.2 for mesiodistal crown width and 0.9 for arch perimeter for maxillary jaw). The crowded group had larger tooth size and smaller arch perimeter.

Conclusion

This study concluded that in males, both the factors i.e., mesiodistal crown width and arch dimensions contributed to dental crowding and the crowded dentition had larger mesiodistal tooth size and smaller arch dimensions; whereas, in females both the factors were not responsible for crowding in Southern Indian population.

Morphometry of the cranial base and the cranial-cervical-mandibular system in young patients with type II, division 1 malocclusion, using tomographic cone beam

AIMS

Traditionally, diagnosis and treatment planning of structural and three-dimensional anomalies have been performed using two-dimensional X-rays. Cone beam computed tomography (CBCT), the technology utilized in this study, allows creation of specialized images from the craniofacial region that provide more precise and reliable results. The growth of the cranial base, position and size of the cervical system, and the hyoid bone has an influence upon the morphogenesis and the growth of the maxillofacial complex. The data obtained through this current study offer a better understanding of the origin and manifestation of malocclusions, and will, therefore, offer a better therapeutic approach. The objective of the current study is to describe the measurements of the cranial base and the cranial-cervical-mandibular system in young patients with type II, division 1 malocclusion, using CBCT.

METHODOLOGY

Twenty-four CBCT images were obtained for young patients with type II, division 1 malocclusion. The i-CAT Vision (Imaging Sciences International, Hatfield, PA, USA) was used to view the images. Linear and angular measurements were obtained in the mid-sagittal plane. Univariate and bivariate analyses, as well as a multivariate analysis of principal components, were conducted.

RESULTS

The only metric with a statistically significant difference regarding gender was S-N major in the male participants. The metrics SNA-SNB and SNPg are positively related and inversely proportional to the angles BA-S-N and PO-P McGregor. The inclination of the upper incisor showed an inverse relationship with the angles SNA-SNB and SNpg. The craniovertebral angle was diminished in the entire sample, and the variable that vertically relates the hyoid was independent of the other variables.

CONCLUSIONS

After evaluating 24 images of young patients with type II, division 1 malocclusion using helical spiral CBCT, it was concluded that relationships exist between the cranial base structures, the structures that determine the sagittal position of the maxilla, mandible and chin, and the cervical vertebrae complex and hyoid bone.