Diagnostic Cone Beam Computed Tomography Research Articles

Simulation-free magnetic resonance-guided radiation therapy of prostate cancer

Background and purposeDespite recent advances of online image-guided high-precision patient positioning and adaptation using magnetic resonance imaging (MRI) or cone-beam computed tomography (CT), standard radiation therapy pathway still involves a dedicated simulation scan. The aim of this study was to evaluate the feasibility and planning quality of integrating a simulation-free treatment planning workflow for adaptive online MRI-guided radiation therapy on a 1.5 T MRI linear accelerator (MRI-Linac) in prostate cancer using diagnostic CT (dCT) scans. Materials and methodsFor ten patients with prostate cancer previously treated at the MRI-Linac with adaptive radiation therapy (42.7 Gy in 7 fractions), simulation-free reference plans based on dCT were retrospectively created, and adaptive plans were simulated for the first treatment fraction. Reference and adapted plans derived from both standard and simulation-free workflows were compared with regard to institutional dose volume criteria, followed by statistical assessment using the paired Wilcoxon signed-rank test with a Bonferroni-corrected significance level of α = 0.025. ResultsSimulation-free reference and adapted plans consistently met dose volume criteria. Statistical analysis revealed no significant differences between both workflows, except median values for near-maximum dose (D2%) in the planning target volume: 44.2 Gy (standard) vs. 44.5 Gy (simulation-free) in reference plans (p = 0.014), and 44.5 Gy vs. 44.6 Gy in adapted plans (p = 0.009). ConclusionThis study demonstrated the feasibility of simulation-free radiation therapy planning using dCT. Comparable treatment plan quality was observed for both reference and adapted radiation therapy plans in a curative setting for patients with prostate cancer.

Projected lifetime cancer risk from cone-beam computed tomography for orthodontic treatment.

ObjectiveTo estimate the projected cancer risk attributable to diagnostic cone-beam computed tomography (CBCT) performed under different exposure settings for orthodontic purposes in children and adults.MethodsWe collected a list of CBCT machines and their specifications from 38 orthodontists. Organ doses were estimated using median and maximum exposure settings of 105 kVp/156.8 mAs and 130 kVp/200 mAs, respectively. The projected cancer risk attributable to CBCT procedures performed 1–3 times within 2 years was calculated for children (aged 5 and 10 years) and adult (aged 20, 30, and 40 years) male and female patients.ResultsFor maximum exposure settings, the mean lifetime fractional ratio (LFR) was 14.28% for children and 0.91% for adults; this indicated that the risk to children was 16 times the risk to adults. For median exposure settings, the mean LFR was 5.25% and 0.58% for children and adults, respectively. The risk of cancer decreased with increasing age. For both median and maximum exposure settings, females showed a higher risk of cancer than did males in all age groups. Cancer risk increased with an increase in the frequency of CBCT procedures within a given period.ConclusionsThe projected dental CBCT-associated cancer risk spans over a wide range depending on the machine parameters and image acquisition settings. Children and female patients are at a higher risk of developing cancer associated with diagnostic CBCT. Therefore, the use of diagnostic CBCT should be justified, and protective measures should be taken to minimize the harmful biological effects of radiation.

Can palatal depth influence the buccolingual inclination of molars? A cone beam computed tomography-based retrospective evaluation.

To interpret a correlation between buccolingual inclination of molars and palatal depth in hyperdivergent patients and to identify importance of determining inclination of molars in assessing transverse discrepancies (as skeletal or dental). This was a retrospective cone beam computed tomography (CBCT) study. The study was conducted in the Department of Orthodontics, Saveetha Dental College and Hospital, Tamil Nadu, India. This was a retrospective CBCT study of 79 patients who underwent diagnostic CBCT for treatment purposes. The CBCT scans were evaluated systematically and the required parameters were accessed with suitable reference planes. Student's t-test (95% confidence interval) was performed to determine buccolingual inclination of first molars between the right and left sides. Only patients with a vertical growth pattern and skeletal class I relation were included and they were classified into three groups based on their palate depth. In patients with palatal depth > 22 mm, the mean inclination of molars was 7.4°; with palatal depth in the range of 19-22 mm, the mean inclination of molars was 5.23°; and with palatal depth < 19 mm, the mean inclination of molars was 2.9°. Results showed that there was a significant correlation between the buccolingual inclination of molars and the palate depth in vertical growers (P < 0.05). The buccolingual inclination of first molars is increased in patients with greater palatal depth. This parameter is helpful in classifying crossbites as skeletal or dental. The amount of compensation required to correct the cross bite can be adjusted using Korkhaus Index.

Validation of cone beam computed tomography-based classification method for individual assessment of mid-palatal suture with respect to clinical application among Indian children.

: The aim of this study is to validate the Fernanda Angelieri classification method for the individual assessment of mid-palatal suture among Indian children using multi-slice computed tomography (CT) with respect to clinical application in rapid maxillary expansion. Present study was conducted utilizing 760 existing head and neck CT image records. CT images were stratified into three categories based on growth spurts: Group I - 6-10 years (n = 210), Group II - 11-14 years (n = 270), and Group III - 15-18 years (n = 280). The CT images were analyzed for stages of mid-palatal suture maturation, according to age and sex. The recorded data were subjected for statistical analysis. Indian children, up to age of 10 years, were distributed in stage A and B. After 11 years, up to 14 years girls showed varied distribution and spread equally among stage B, C, and D. After 15 years, more number of girls were distributed in stage D and E, whereas boys remained distributed variedly in stage B, C, and D. Mid- palatal suture maturational stages correlated to chronological age among both the genders using Fisher exact test and expected contingency table showed statistically significant variation among both the gender independently and collectively (P < 0.001). Cone beam computed tomography (CBCT)-based prediction of stages of mid- palatal suture maturation by Fernanda Angelieri is valid among the Indian population. During treatment plan of maxillary expansion among children above 10 years, it is better to have a diagnostic CBCT image analysis of mid-palate suture for predicable prognosis.

Three-dimensional printing: A revealing pathway to an unpredictable maze

Three-dimensional (3D) technology has gained wide acceptance in dentistry. It has been used for treatment planning and surgical guidance. This case report presented a novel treatment approach to remove and preserve the cortical bone and root-end resection during periapical surgery with the help of cone-beam computed tomography (CBCT), computer-aided design, and 3D printing technology. A 22-year-old male patient presented with a large periapical lesion in the right maxillary central and lateral incisors was referred for endodontic surgery. The data acquired from a preoperative diagnostic CBCT scan and an intraoral scan were uploaded into surgical planning software and matched. A template that could be used to locate root ends and lesion areas was virtually designed based on the data and was fabricated using a 3D printer. With the guidance of the template, the overlying cortical bone was precisely removed and preserved, and apicectomy was performed. The patient was clinically asymptomatic at a 6-month follow-up review. Six months after the surgery, the lesion was healing well, and no periapical radiolucency was observed on radiographic examination. The digitally designed directional template worked in all aspects to facilitate the periapical surgery as anticipated. The root ends were accurately located and resected. The surgical procedure was simplified, and the treatment efficiency was improved. This technique minimized the damage and reduced iatrogenic injury.

Comparison of Five different methods of Working length determination: An ex vivo study

Aim: The aim of the study was to determine the accuracy and reliability of working length determination using tactile sensation method, digital radiographic method, and electronic apex locator (EAL) in lower premolars in vivo and to compare the lengths so measured to the working length measured with cone-beam computed tomography (CBCT) and the actual working length (AWL) with magnifying loupe, ex vivo. Materials and Methods: Thirty mandibular premolars scheduled for orthodontic extraction were selected. Under local anesthesia, access cavities were prepared and the working lengths were determined by two operators after blinding, using the tactile sensation method, digital radiographic method (radiovisiography [RVG]), and EAL, and tabulated. The teeth were then extracted and subjected to CBCT to determine the working length (CBCTWL). The AWL of the teeth was measured with a K-file that was inserted into the root canal until the file tip is visible at the apical foramen which was confirmed using a magnifying loupe (×8). The values were then statistically analyzed. Statistical Analysis: The SPSS version 20 software (IBM Corp., Armonk, NY, USA) was used to perform statistical analyses, and the confidence interval was determined at P Results: There is a significant difference between the methods in determining the working length. Based on the correlation values on reliability, CBCT method has a more positive correlation with AWL measured using magnifying loupe, followed by EAL, RVG, and tactile sensation. Conclusion: Hence, we conclude that the use of EAL technique is clinically effective for measuring the working length which correlates more positively with the CBCTWL and AWL. Diagnostic CBCT scan can be used as a reliable method for determining the working length.

PREVALENCE OF PNEUMATIZATION OF THE CRISTA GALLI IN DENTAL PATIENTS

<h3>Background</h3> A large field of view (FOV) cone beam computed tomography (CBCT) scan can show an anatomic variant, such as pneumatization of the crista galli. The crista galli is a bony projection that extends superiorly from the cribriform plate of the ethmoid bone. It is located at the midline of the anterior cranial fossa and is where the falx cerebri attaches anteriorly. As there is no literature on this topic using CBCT imaging, we undertook this study to add to the research as well as to inform dentists and specialists about pneumatization of crista galli. <h3>Objective(s)</h3> The aim of this study was to report the prevalence of pneumatization of the crista galli using CBCT images and to compare the prevalence of pneumatization of crista galli in patients receiving nonsurgical versus surgical dental treatment. <h3>Study Design</h3> The study included 514 diagnostic CBCT scans from 2015 to 2016. Age, sex, treatment provided, and the size of pneumatized crista galli were recorded. The associations between age and sex versus pneumatization of the crista galli were evaluated using the Mann-Whitney U test. The associations between treatment and pneumatization of crista galli were assessed using Pearson's χ² and Fischer's exact tests. <h3>Results</h3> The average age of the patients was 15.69 years. Pneumatization of crista galli occurred in 20 out of 514 (3.8%) patients. The median cranial–caudal length of a pneumatized crista galli was 4.78 mm in females and 5.62 mm in males. The median width was 4.49 mm in females and 6.98 mm in males. Patients with pneumatization were statistically significantly older than the patients without pneumatization (U = 3041.5; <i>P</i> = .004). Among the nonsurgical categories, orthodontic treatment was classified as significant (<i>P</i> = .008). Among surgical categories, orthognathic surgery was found to be significant in the presentation of pneumatization of the crista galli (<i>P</i> = .001). Fischer's exact test showed there was a significantly higher percentage of surgical patients with pneumatization compared with nonsurgical patients (<i>P</i> = .003). <h3>Discussion/Conclusions</h3> Age, orthodontic treatment, and orthognathic surgery were significantly associated with pneumatization of the crista galli. Gender did not contribute substantially to pneumatization of the crista galli.

A novel method for periapical microsurgery with the aid of 3D technology: a case report

BackgroundThree-dimensional (3D) technology has gained wide acceptance in dentistry. It has been used for treatment planning and surgical guidance. This case report presented a novel treatment approach to remove cortical bone and root-end during periapical surgery with the help of Cone-Beam Computed Tomography (CBCT), Computer Aided Design (CAD) and three-dimensional (3D) printing technology.Case presentationA 37-year-old female patient presented with a large periapical lesion of left maxillary lateral incisor and canine was referred for microsurgical endodontic surgery. The data acquired from a preoperative diagnostic CBCT scan and an intra-oral scan was uploaded into surgical planning software and matched. A template that could be used to locate root-ends and lesion areas was virtually designed based on the data and was fabricated using a 3D printer. With the guidance of the template, the overlying cortical bone and root-end were precisely removed by utilizing a trephine with an external diameter of 4.0 mm. The patient was clinically asymptomatic at a six-month follow-up review. One year after the surgery, the lesion was healing well and no periapical radiolucency was observed on radiographic examination.ConclusionsThe digitally designed directional template worked in all aspects to facilitate the periapical surgery as anticipated. The root-ends were accurately located and resected. The surgical procedure was simplified, and the treatment efficiency was improved. This technique minimized the damage and reduced iatrogenic injury.

Noise Properties of Chord-Image Reconstruction

Recently, there has been much progress in algorithm development for image reconstruction in cone-beam computed tomography (CT). Current algorithms, including the chord-based algorithms, now accept minimal data sets for obtaining images on volume regions-of-interest (ROIs) thereby potentially allowing for reduction of X-ray dose in diagnostic CT. As these developments are relatively new, little effort has been directed at investigating the response of the resulting algorithm implementations to physical factors such as data noise. In this paper, we perform an investigation on the noise properties of ROI images reconstructed by using chord-based algorithms for different scanning configurations. We find that, for the cases under study, the chord-based algorithms yield images with comparable quality. Additionally, it is observed that, in many situations, large data sets contain extraneous data that may not reduce the ROI-image variances.