Cone-beam Computed Tomography CT Research Articles

Comparison of cone-beam and fan-beam computed tomography and low-field magnetic resonance imaging for detection of palmar/plantar osteochondral disease in Thoroughbred horses.

Palmar/plantar osteochondral disease (POD) of the metacarpal/tarsal condyles is a common pathological finding in racehorses. To compare diagnoses, imaging details, and measurements of POD lesions between cone-beam computed tomography CT (CBCT), fan-beam CT (FBCT), and low-field magnetic resonance imaging (MRI) using macroscopic pathology as a gold standard. Cross-sectional study. Thirty-five cadaver limbs from 10 horses underwent CBCT, FBCT, MRI, and macroscopic examination. CT and MR images were examined for presence of POD, imaging details of POD, and measurements of POD dimensions and areas. Imaging diagnoses, details, and measurements were compared with macroscopic examination and between modalities. Forty-eight POD lesions were seen over 70 condyles. Compared with macroscopic examination the sensitivity and specificity of diagnosis were 95.8% (CI95 = 88%-99%) and 63.6% (CI95 = 43%-81%) for FBCT, 85.4% (CI95 = 74%-94%) and 81.8% (CI95 = 63%-94%) for CBCT, and 69.0% (CI95 = 54%-82%) and 71.4% (CI95 = 46%-90%) for MRI. Inter-modality agreement on diagnosis was moderate between CBCT and FBCT (κ = 0.56, p < 0.001). POD was identified on CT as hypoattenuating lesions with surrounding hyperattenuation and on MRI as either T1W, T2*W, T2W, and STIR hyperintense lesions or T1W and T2*W heterogeneous hypointense lesions with surrounding hypointensity. Agreement on imaging details between CBCT and FBCT was substantial for subchondral irregularity (κ = 0.61, p < 0.001). Macroscopic POD width strongly correlated with MRI (r = 0.81, p < 0.001) and CBCT (r = 0.79, p < 0.001) and moderately correlated with FBCT (r = 0.69, p < 0.001). Macroscopic POD width was greater than all imaging modality (p < 0.001). Effect of motion artefact in live horse imaging could not be assessed. All imaging modalities were able to detect POD lesions, but underestimated lesion size. The CT systems were more sensitive, but the differing patterns of signal intensity may suggest that MRI can detect changes associated with POD pathological status or severity. The image features observed by CBCT and FBCT were similar.

Organ-aware CBCT enhancement via dual path learning for prostate cancer treatment.

Cone-beam computed tomography (CBCT) plays a crucial role in the intensity modulated radiotherapy (IMRT) of prostate cancer. However, poor image contrast and fuzzy organ boundaries pose challenges to precise targeting for dose delivery and plan reoptimization for adaptivetherapy. In this work, we aim to enhance pelvic CBCT images by translating them to high-quality CT images with a particular focus on the anatomical structures important for radiotherapy. We develop a novel dual-path learning framework, covering both global and local information, for organ-aware enhancement of the prostate, bladder and rectum. The global path learns coarse inter-modality translation at the image level. The local path learns organ-aware translation at the regional level. This dual-path learning architecture can serve as a plug-and-play module adaptable to other medical image-to-image translationframeworks. We evaluated the performance of the proposed method both quantitatively and qualitatively. The training dataset consists of unpaired 40 CBCT and 40 CT scans, the validation dataset consists of 5 paired CBCT-CT scans, and the testing dataset consists of 10 paired CBCT-CT scans. The peak signal-to-noise ratio (PSNR) between enhanced CBCT and reference CT images is 27.22 ± 1.79, and the structural similarity (SSIM) between enhanced CBCT and the reference CT images is 0.71 ± 0.03. We also compared our method with state-of-the-art image-to-image translation methods, where our method achieves the best performance. Moreover, the statistical analysis confirms that the improvements achieved by our method are statistically significant. The proposed method demonstrates its superiority in enhancing pelvic CBCT images, especially at the organ level, compared to relevant methods.

CT-CBCT deformable registration using weakly-supervised artifact-suppression transfer learning network

Objective. Computed tomography-cone-beam computed tomography (CT-CBCT) deformable registration has great potential in adaptive radiotherapy. It plays an important role in tumor tracking, secondary planning, accurate irradiation, and the protection of at-risk organs. Neural networks have been improving CT-CBCT deformable registration, and almost all registration algorithms based on neural networks rely on the gray values of both CT and CBCT. The gray value is a key factor in the loss function, parameter training, and final efficacy of the registration. Unfortunately, the scattering artifacts in CBCT affect the gray values of different pixels inconsistently. Therefore, the direct registration of the original CT-CBCT introduces artifact superposition loss. Approach. In this study, a histogram analysis method for the gray values was used. Based on an analysis of the gray value distribution characteristics of different regions in CT and CBCT, the degree of superposition of the artifact in the region of disinterest was found to be much higher than that in the region of interest. Moreover, the former was the main reason for artifact superposition loss. Consequently, a new weakly supervised two-stage transfer-learning network based on artifact suppression was proposed. The first stage was a pre-training network designed to suppress artifacts contained in the region of disinterest. The second stage was a convolutional neural network that registered the suppressed CBCT and CT. Main Results. Through a comparative test of the thoracic CT-CBCT deformable registration, whose data were collected from the Elekta XVI system, the rationality and accuracy after artifact suppression were confirmed to be significantly improved compared with the other algorithms without artifact suppression. Significance. This study proposed and verified a new deformable registration method with multi-stage neural networks, which can effectively suppress artifacts and further improve registration by incorporating a pre-training technique and an attention mechanism.

Accuracy of an electrical impedance device in estimation of remaining dentin thickness vs cone beam computed tomography.

The objective of this study is to compare the estimated values of remaining dentin thickness (RDT) recorded by a newly introduced electrical impedance device (Prepometer) with cone beam computed tomography (CBCT) and histological in situ measurement. A total number of thirty human molars were used in this study. A deep class I cavity was prepared. The RDT for each cavity was measured with Prepometer in three different points (mesial, middle, and distal). Same specimens were imaged with high-resolution Cone Beam Computed Tomography CBCT (0.1mm voxel size) using I CAT next Generation Machine (Imaging Science International, Hatfield, PA, USA), to provide the highest possible accuracy of linear measurements. Finally, the specimens were vertically sectioned parallel to the long axis of the tooth in a mesiodistal direction splitting the cavity into two halves through its center. Then, the actual RDT of each half will be measured in the same three points using a digital caliper. The outcome of one-way ANOVA revealed that there was no significant difference in RDT values measured by prepometer device, CBCT, or histological sectioning methods (p > 0.05). Within the limitations of this laboratory study, prepometer seems to be a potential non-invasive accurate measuring tool for RDT. Based on the findings of this study, the Prepometer can be considered as an easily handled and less-expensive method compared to CBCT to evaluate the RDT. Also, it can be used in dental schools and with less-experienced operators to avoid traumatic exposures of the dental pulp.

Volumetric Analysis of the Pterygopalatine Fossa by Semiautomatic Segmentation of Cone Beam Computed Tomography.

The aim of this study was to provide volumetric data of the pterygopalatine fossa by semiautomatic segmentation based upon cone beam computed tomography.Cone beam computed tomography (CBCT) images of 100 patients were analyzed. By using the open source software "ITK-Snap," the volumetric measurements of 200 pterygopalatine fossae were performed. For statistical investigations paired t test, and independent Student t test were performed. Also, the Pearsons chi-square test was applied. P values P < 0.05 were considered significant.The mean volume was 578.376 mm for the right and 560.979 mm for the left side. The results indicated statistically significant differences according to the right and the left pterygopalatine fossa, regardless of gender (P < 0.05). The analysis of differences between males and females did not show any significant results (P > 0.05), although males present a slightly larger volume than females. According to the median age (59 years), younger patients presented smaller volumes, whereas older patients presented larger volumes. Nevertheless, no statistically significant differences according to age (χ = 3.520; P > 0.05) could be found.Clinical intervention with the application of local anesthetics into the complex and vulnerable anatomy of the pterygopalatine fossa makes a thorough knowledge about the volumetric capacity indispensable. Therefore, the semiautomatic segmentation of CBCT images provides a useful, available and validated tool. Our results show that a final injected anesthetic volume larger than 1 ml exceeds the pterygopalatine fossa capacity considerably and could cause complications. To prevent this, volumetric analysis of this region can provide further information and enables an individualized patients' treatment.

EVALUATION OF ARTIFACTS GENERATED BY TITANIUM, ZIRCONIUM, AND TITANIUM-ZIRCONIUM ALLOY DENTAL IMPLANTS IN MRI, CT, AND CBCT IMAGES: AN IN VITRO STUDY

<h3>Background</h3> Magnetic resonance imaging (MRI) or computed tomography/cone beam computed tomography (CT/CBCT) should be performed in implant therapy when the conventional image is not adequate or when more information is needed to improve the patient's treatment. Therefore, 3-D imaging may be required even when the implants are present in the field of view (FOV). Thus, determining the most suitable imaging technique and setting for each type of implant material will facilitate the radiologists ability to give the best care to the patient. <h3>Objective(s)</h3> The aim of this study was to assess the amount and structure of artifacts caused by titanium grade 4 and 5, zirconium, and titanium–zirconium alloy implants in MRI, CT, and CBCT with several acquisition protocols and to correlate the findings to the radiation dose given by 2 different CT machines and different CBCT exposure settings. <h3>Study Design</h3> Three phantoms were built by embedding titanium, zirconium, and titanium–zirconium alloy implants in ultrasound gel. MRI, CT, and CBCT images were acquired using multiple sequences and settings. For MRI, the artifact was described as the length of signal void beyond the limits of the implant. For CT and CBCT, the artifact was calculated by subtracting the gray level of the darkest pixel from the one of the lightest pixel. <h3>Results</h3> Titanium and titanium–zirconium alloy implants created extensive artifacts in MRI as a result of high susceptibility, whereas zirconium implants could be correctly depicted with only minor distortion artifacts. However, in CT and CBCT, titanium and titanium–zirconium alloy implants generated less severe artifacts than zirconium. <h3>Discussion/Conclusions</h3> MRI images were less affected by the artifacts from zirconium implants, whereas CT and CBCT images showed fewer artifacts from titanium and titanium–zirconium alloy implants. CBCT, especially at low dose settings, produced the least amount of radiation compared with high-resolution settings and 2 CT machines.

Accuracy of panoramic radiography in diagnosing maxillary sinus-root relationship: A systematic review and meta-analysis.

To investigate the accuracy of panoramic radiography (PR) in diagnosing maxillary sinus-root relationships (SRRs). PubMed, EMBASE, CENTRAL, Web of Science, ScienceDirect, CBM, Baidu Scholar, and SIGLE were searched. The studies comparing the diagnostic accuracy of PR and computed tomography/cone-beam computed tomography (CT/CBCT) for SRR were included. Eleven studies were included. Meta-analyses showed that, for type I SRR, PR had the highest specificity, positive likelihood ratio (+LR), diagnostic odds ratio (DOR), and area under the curve (AUC), with a high sensitivity and a low negative LR (-LR). For type IV, PR had a high DOR and AUC, with the highest sensitivity but a low +LR, the lowest -LR, and the lowest specificity. For type II, PR had the lowest AUC, with a low sensitivity, +LR, and DOR and a high -LR. For type III, PR had the lowest sensitivity, +LR, and DOR and the highest -LR. The distance from root tips to the maxillary sinus floor on PR was significantly longer (mean difference: -1.88 mm; 95% confidence interval: -2.19 to -1.57; P < .0001) than that on CT/CBCT. Currently available evidence suggests PR could be reliable for detecting type I SRR. PR has a good ability to confirm true type IV SRR but a poor ability to rule out false type IV SRR. For type II and III SRR, PR shows poor accuracy and tends to overestimate the extent of protrusion of the roots into the maxillary sinus. When PRs display type II, III, or IV SRR and related treatment is needed, CBCT should be used for further examinations.

Anatomical variation in the dimension of nasopalatine canal on Cone Beam Computed Tomography CBCT images among sulaimani population

Objective: This study was conducted to find anatomical variation of nasopalatine canal (NPC) and nasopalatine foramen (NPF) in different age and gender groups among Sulaimani population on cone beam computed tomography (CBCT) images. Subjects and Methods: The study included one hundred CBCT images obtained from patients visiting privet clinics with specialty in dental and maxillofacial radiology in Sulaimani city extended from 2014 to 2016. Subjects were divided into three age groups (18-34, 35-49, 50-75) years old. First group included 15 males and 15 females, second group 20 males and 20 females, and the third group included 15 males with 15 females. PaX i vatech digital CBCT machine, were used to obtain the images by the radiographers. The following measurements were estimated; number of openings of NPC at nasal fossa, mesio-lateral diameter 0f NPF at nasal fossa (axial section), mesio-lateral diameter of NPF at palatine fossa, antero-posterior dimension of NPC at: its upper boarder; middle level, and lower boarder, and lastly the height of NPC in sagittal section. Results: 100 subjects (50 males and 50 females) with age range 31 year were included in this study. 69% had single NPF at the nasal fossa. 23% had two openings and 8% had three openings. Mean and standard deviation (SD) of mesio-lateral diameter of NPF at nasal fossa, and palatine fossa were 2.60±0.69 mm, and 4.11±2.09 mm respectively. NPF diameter at the palatine fossa showed significant differences between genders (P value less than 0.05). But age group differences did not reach the significant level (P value more than 0.05). The means and SD of antero-posterior dimension of NPC was 3.46±1.53 mm. There were no significant difference between genders and among age groups concerning this dimension (P value was greater than 0.05). Mean and SD of height of NPC was 13.14±3.11 mm. Males demonstrated significantly greater length of NPC than females (P value was less than 0.05). Conclusion: It is concluded that there is anatomical variation in morphology and various parameters of NPC among sulaimani population. This should be considered in preoperative planning and to reduce the number of complications in implant and other maxillofacial surgeries in anterior palatine area. CBCT has important role to obtain accurate measurements of NPC different dimensions which has importance to differentiate between normal and abnormal NPC.

Three-dimensional analysis of effects of rapid maxillary expansion on facial sutures and bones: A systematic review

To evaluate the evidence on three-dimensional immediate effects of rapid maxillary expansion (RME) treatment on growing patients as assessed by computed tomography/cone beam computed tomography (CT/CBCT) imaging. The published literature was searched through the PubMed, Embase, and Cochrane Library electronic databases from January 1966 to December 2012. The inclusion criteria consisted of randomized controlled trials, prospective controlled studies, and prospective case-series. Two reviewers extracted the data independently and assessed the quality of the studies. The search strategy resulted in 73 abstracts or full-text articles, of which 10 met the inclusion criteria. When treating posterior crossbites with a RME device, the existing evidence points out that the midpalatal suture opening is around 20%-50% of the total screw expansion. There seems to be no consistent evidence on whether the midpalatal sutural opening is parallel or triangular. The effect on the nasal cavity dimensions after RME seems to be apparent and indicates an enlargement between 17% and 33% of the total screw expansion. Circummaxillary sutures, particularly the zygomaticomaxillary and frontomaxillary sutures and also spheno-occipital synchondrosis, appear to be affected by the maxillary expansion. Overall, however, the changes were small and the evidence not conclusive. CT imaging proved to be a useful tool for assessment of treatment effects in all three dimensions. The majority of the articles were judged to be of low quality, and therefore, no evidence-based conclusions could to be drawn from these studies.

An Open System Approach for Surgical Guide Production

Surgical guides for oral implantology were made with a new open system independent of implant planning software based on a universal computed tomography/cone beam computed tomography (CBCT) scan plate for fiducial markers. For this in vitro study, CBCT scans were taken of 18 models based on a universal computed tomography/CBCT scan plate (Bego Medical, Bremen, Germany) for fiducial markers. The models were made from radiopaque composite with several integrated radiopaque gutta-percha points used as a reference. The coDiagnostiX (Institut Straumann, Basel, Switzerland) and implant 3D (med3D, Heidelberg, Germany) software programs were used for virtual implant planning. Coupling devices on the scan plate allowed for the precise connection to a special transfer plate (Bego Medical), which transfers the implant position to the drill guide. The horizontal distance of the final implant position to the gutta-percha markers was compared with the implant planning values. Planning of 18 implants was performed with the Institut Straumann system and 18 with the med3D system. The horizontal deviation of the final implant placement compared with the implant planning made with the med3D system showed a mean error of 0.33 mm for implants 1 and 2. The difference between the CBCT measurements of the Institut Straumann models was larger than that of the med3D measurements. The mean error for implant 1 was 0.65 mm and 1.13 mm for implant 2. The reduction in the dental laboratory costs, the freedom to use different implant planning software programs, and the easy handling might facilitate the distribution of guided surgery and provide significant benefits for the clinician and the dental laboratory.