Morphological analysis of anatomical structure of nasopharynx in cone-beam computed tomography in Korean population

Nasopharynx on Cone-beam Computed Tomography.

Objective:This study aimed to examine the morphological characteristics of the nasopharynx in unilateral Cleft lip/palate (CL/P) children and non-cleft children using cone beam computed tomography (CBCT).Methods:A retrospective study consisted of 54 patients, of which 27 patients were unilateral CL/P, remaining 27 patients have no CL/P. Eustachian tubes orifice (ET), Rosenmuller fossa (RF) depth, presence of pharyngeal bursa (PB), the distance of posterior nasal spine (PNS)-pharynx posterior wall were quantitatively evaluated.Results:The main effect of the CL/P groups was found to be effective on RF depth-right (p < 0.001) and RF depth-left (p < 0.001). The interaction effect of gender and CL/P groups was not influential on measurements. The cleft-side main effect was found to be effective on RF depth-left (p < 0.001) and RF depth-right (p = 0.0002). There was no statistically significant relationship between CL/P groups and the presence of bursa pharyngea.Conclusions:Because RF is the most common site of nasopharyngeal carcinoma (NPC), the anatomy of the nasopharynx should be well known in the early diagnosis of NPC.

To evaluate the radiological anatomy of the pharyngeal recess (PR) by gender and age. Images of patients who underwent cone-beam computed tomography (CBCT) were analyzed retrospectively. A total of 600 PRs (140 male, 160 female) were examined. PR depths, distances between the posterior nasal spine (PNS) and the posterior wall of the pharynx, right and left torus levatorius lengths, and distances between the right and left torus levatorius were measured on the axial plane passing through the PNS-basion point. PR depths differed significantly between age groups (right p = 0.030, left p = 0.047). The PR depths of individuals under 35years of age were significantly higher than those of individuals aged 35 and over. Further, the distances between the PNS and the posterior wall of the pharynx differed significantly between age groups and between gender groups. The distances between the PNS and the posterior wall of the pharynx were shorter in patients under 35years of age (p = 0.000). In terms of gender, these distances were significantly longer in males (p = 0.014). The distances between the right and left torus levatorius were also significantly longer in males (p = 0.029). The PR is the region in which nasopharyngeal carcinoma originates most frequently and is very important for early diagnosis. The present results indicated that this region can be examined with CBCT.

The Image Gently in Dentistry campaign: promotion of responsible use of maxillofacial radiology in dentistry for children.

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Background This study aimed to assess the diagnostic accuracy of cone beam computed tomography (CBCT) and quantitatively evaluate the morphology of mandibular first molars using CBCT. Material and Methods Twenty-four double-rooted mandibular first molars were evaluated by NewTom VGi CBCT. The distance from the furcation and apex to the cementoenamel junction (CEJ), diameter and thickness of canal walls, the buccolingual (BL) to mesiodistal (MD) ratio (ΔD), prevalence of oval canals at different sections and taper of the canals were all determined. In order to assess the diagnostic accuracy of CBCT, distance from the furcation and apex to the CEJ and thickness of canal walls at the CEJ and apex were compared with the gold standard values (caliper and stereomicroscope). Statistical analyses were carried out using intraclass correlation coefficient (ICC), paired t-test and repeated measures ANOVA. Results A high correlation existed between the CBCT and gold standard measurements (P<0.001). In dimensional measurements, length of mesial root was higher than the distal root and lingual furcation was farther from the CEJ than the buccal furcation (P<0.001). An important finding of this study was the mesiodistal taper of the mesiobuccal (MB) and mesiolingual (ML) canals; which was equal to 0.02. Conclusions CBCT has acceptable diagnostic accuracy for measurement of canal wall thickness. Cleaning and shaping of the canals should be performed based on the unique anatomy of the respective canal; which necessitates the use of advanced imaging techniques for thorough assessment of root canal anatomy in a clinical setting. Key words:Permanent mandibular first molar, accuracy, cone-beam computed tomography, dimensional measurement.

Objective To study the more safe and accurate guidance scheme of cone beam computed tomography (CBCT) in nasopharyngeal carcinoma. Methods CBCT was regularly performed on 87 patients with nasopharyngeal carcinoma in Meizhou People's Hospital from November 2014 to August 2015. For each patient, 10 times CBCT scans were obtained pre-treatment. All the setup errors were obtained and analysed on the orientation X (left and right), Y (head and foot) and Z (vertical) axis. Results With the increase of the number of CBCT scans, there was no statistically significant difference among the mean setup errors of the 10 times scans in X (left and right) and Y (head and foot) directions (all P > 0.05). And there was no statistically significant difference among the mean setup errors of 6 times scans in Z (vertical) direction, but from the beginning of the 7th, the systematic error in Z direction was increasing, the system error of the 7th, 8th, 9th, 10th time was 0.140, 0.292, 0.461, and 0.640 mm. Moreover, the difference of the mean systematic errors among the first 7 times was statistically significant (H = 15.232, P = 0.019), and the differences of the mean systematic errors among the first 8, 9 and 10 times were statistically significant (all P < 0.05). Conclusions Non-consecutive scans of CBCT could reduce the systematic and random errors. The appropriate frequency of application of CBCT based on the change law of setup errors is an ideal CBCT guidance scheme for nasopharyngeal carcinoma. Key words: Nasopharyngeal neoplasms; Imaging guided radiation therapy; Cone beam computed tomography; Setup errors

본 연구는 CBCT(Cone-beam computed tomography)영상에서 미맹출 치아 크기 측정의 재현성과 정확성을 평가하기 위해 시행되었다. 매복치를 주소로 부산대학교 치과병원 소아치과에 내원한 혼합치열기 환자 중 진단 목적으로 CBCT 채득에 동의한 환자의 미맹출 견치 및 소구치 69개를 대상으로 하였다. CBCT 영상에서 측정한 미맹출 치아의 최대 근원심 폭경 계측치와 동일한 치아가 구강 내로 완전히 맹출한 후 채득한 석고 모형에서 대상 치아를 digital caliper로 측정한 최대 근원심 폭경 계측치를 비교하여 다음과 같은 결론을 얻었다. 1. CBCT 영상에서 미맹출 치아를 계측하는 방법은 재현성이 높다(ICC=0.91). 2. CBCT 영상에서 측정한 미맹출 치아의 최대 근원심 폭경 계측치와 석고 모형에서 측정한 대상 치아의 최대 근원심 폭경 계측치는 높은 상관 관계가 있었다(r=0.91). 3. CBCT 영상에서 측정한 미맹출 치아 최대 근원심 폭경 계측치와 석고 모형에서 측정한 대상 치아의 최대 근원심 폭경 계측치는 통계적으로 유의한 차이가 있었다(<TEX>$p$</TEX> <0.05). CBCT 영상에서 측정한 미맹출 치아 최대 근원심 폭경의 계측치가 석고 모형에서 측정한 대상 치아의 최대 근원심 폭경 계측치보다 평균 0.2 mm 작게 측정되었다. 그러나 이러한 차이는 임상적으로 수용 가능한 수준이라 생각된다. The purpose of this study was to evaluate the accuracy and reproducibility of measuring the size of unerupted permanent tooth via cone beam computed tomography(CBCT). Ten children were scanned with dental CBCT, and 3-dimensional reconstruction of the dentitions were generated CBCT. Mesio-distal dimension and buccolingual dimension of the teeth were made directly on the model with a high-precision digitalcaliper and on the CBCT by using three-dimensional dental imaging software. Reliability and accuracy were assessed by using intraclass correlation and paired <TEX>$t$</TEX>-tests. (<TEX>$p$</TEX> <0.05) The results were as follows : 1. Intraclass correlations were above 0.9 for Both the CBCT and the model measurements, showinghigh reliability. 2. Although there were high correlation values(r=0.91) between CBCT and model messurement methods, comparisons between the CBCT and model messurement methods showed a statistically significant difference(<TEX>$p$</TEX> <0.05). 3. The CBCT measurements tended to slightly underestimate by 0.2 mm. But, the systematic difference of CBCT measurements were clinically acceptable Therefore, CBCT measurement method can be used to measure the size of unerupted teeth in a sufficiently accurate way.

The diagnostic reliability of skin biopsy in small fiber neuropathy depends on the availability of normative reference values. We performed a multicenter study to assess the normative values of intraepidermal nerve fiber (IENF) density at distal leg stratified by age deciles. Eight skin biopsy laboratories from Europe, USA, and Asia submitted eligible data. Inclusion criteria of raw data were healthy subjects 18 years or older; known age and gender; 3-mm skin biopsy performed 10-cm above the lateral malleolus; bright-field immunohistochemistry protocol, and quantification of linear IENF density in three 50-µm sections according to published guidelines. Data on height and weight were recorded, and body mass index (BMI) was calculated in subjects with both available data. Normative IENF density reference values were calculated through quantile regression analysis; influence of height, weight, or BMI was determined by regression analyses. IENF densities from 550 participants (285 women, 265 men) were pooled. We found a significant age-dependent decrease of IENF density in both genders (women p < 0.001; men p = 0.002). Height, weight, or BMI did not influence the calculated 5th percentile IENF normative densities in both genders. Our study provides IENF density normative reference values at the distal leg to be used in clinical practice.

Objectives: The effect of radiation after exposing with dental imaging devices on cell-implant material interaction has not been adequately studied. The aim of this study is to determine the effects of radiation by measuring proliferation and differentiation of the human fetal osteoblast (hFOB) cells using dental imaging techniques and evaluate the result in vitro conditions at cellular stage. Materials and Methods: hFOB were irradiated 1 day after planting on commercially pure titanium discs. Radiation was single dose in one exposure using five different dental imaging techniques as conventional dental and digital dental X-ray tubes, conventional panoramic, digital panoramic and cone beam computerized tomography (CBCT). In the 8 th day of experiment, exposured cells and nonexposured control group cells which planted on discs were compared and examined regarding their proliferations and alkaline phosphatase (ALP) activities. Results were evaluated using Student's Independent t-test in SPSS 15.0 (SPSS Inc., Chicago, IL, USA). Results: In exposure with digital dental imaging device, ALP activities of cells are increased according to the control group and statistically, with 0, 2 s of exposure, a significant increment was found (P < 0.05). The exposures with CBCT and conventional dental imaging devices decreased cell proliferation compared with the control groups, but it was found statistically insignificant. In exposure with the other dental imaging devices, cell proliferation increased insignificantly. Conclusions: Our in vitro study suggests that the ionizing radiation produced by digital dental imaging devices may result to certain increment of the cell number and activities. More controlled study should be made with cell cultures in order to verify the exact activity of digital dental imaging.

Nasopharyngeal carcinoma (NPC) is an endemic malignant disease in\n\nSouthern China. Intensity-modulated radiotherapy (IMRT) has been employed as a standard treatment for NPC because it delivers highly conformal dose\n\ndistribution to target volumes and spares organs at risk (OARs). The success of radiotherapy depends on the accurate delivery of the planned doses throughout the treatment. This can be achieved with the help of advanced image-guided adaptive radiotherapy (IGART) such as kilovoltage (kV) cone beam computed tomography (CBCT) which can reduce the geometric setup uncertainty, monitor the intra-course anatomic and dosimetric changes and adjust the treatment plan.\n\n\n\nThe aim of this thesis is to study the role of repeat imaging for NPC and the radiation dose from CBCT to patients. The objectives of this thesis are to evaluate the volumetric and dosimetric changes during a course of IMRT for loco-regionally advanced NPC patients with the contribution of repeat computed tomography (CT) and magnetic resonance imaging (MRI) scans; to quantify the absorbed dose, effective dose and the estimation of the additional risk of inducing fatal cancers from CBCT for NPC patients undergoing IMRT; and to compare the image quality of different head protocols.\n\n\n\nNineteen loco-regionally advanced NPC patients treated with IMRT were recruited prospectively. Repeat CT and MRI were acquired at 30 and 50 Gy\n\nintervals. Recontouring of target volumes and OARs was based on the fused CT-MRI images. Hybrid plans with recontouring were generated. The volumetric and dosimetric changes were assessed by comparing the hybrid plans with the original plan. There was volume reduction of target volumes and parotid glands over the course of IMRT. Relative to the original plan, the hybrid plans demonstrated significantly higher dose to the target volumes with greater dose inhomogeneity, higher maximum doses to the spinal cord and brainstem, and higher medium doses to the parotid glands.\n\n\n\nThe image quality and dosimetry on the Varian CBCT system between software Versions 1.4.13 (“new” protocol) and 1.4.11 (“old” protocol) were studied. A calibrated Farmer-type ionization chamber and a standard cylindrical Perspex CT dosimetry head phantom were used to measure the weighted CBCT dose index (CBCTDIw) of the Varian CBCT system. The absorbed dose of different organs was measured in a female anthropomorphic phantom with thermoluminescent dosimeters (TLD) and the total effective dose was estimated according to ICRP Publication 103. The dosimetry and image quality were studied for head-and-neck region and comparison was made between the new and old protocols. The values of the CBCTDIw, absorbed dose, effective dose of the new head protocol were much lower than the old head protocol in each imaging group. The additional fatal cancer risk from daily CBCT might be up to 1.6%. In conclusion, replanning with repeat imaging at 30 Gy is essential to keep a satisfactory dose to the target volumes and avoid overdosing the OARs for NPC patients. The new Varian CBCT provides volumetric information for image guidance with acceptable image quality and lower radiation dose. This CBCT gives a better standard for NPC patient daily setup verification.

Recent advances in cone beam computed tomography (CBCT) in dentistry have identified the importance of providing outcomes related to the appropriate use of this innovative technology to practitioners, educators, and investigators. To assist in determining whether and what types of evidence exist, the authors conducted PubMed, Google, and Cochrane Library searches in the spring of 2011 using the key words "cone beam computed tomography and dentistry." This search resulted in over 26,900 entries in more than 700 articles including forty-one reviews recently published in national and international journals. This article is based on existing publications and studies and will provide readers with an overview of the advantages, disadvantages, and indications/contraindications of this emerging technology as well as some thoughts on the current educational status of CBCT in U.S. dental schools. It is the responsibility of dental educators to incorporate the most updated information on this technology into their curricula in a timely manner, so that the next generation of oral health providers and educators will be competent in utilizing this technology for the best interest of patients. To do so, there is a need to conduct studies meeting methodological standards to demonstrate the diagnostic efficacy of CBCT in the dental field.

To determine the diagnostic yield of cone beam computed tomography (CBCT) compared with 3 T magnetic resonance imaging (MRI) for the evaluation of subchondral insufficiency fractures of the knee. Consecutive patients with subchondral insufficiency fractures of the knee examined by 3 T MRI and CBCT of the femoral condyles were reviewed. Two experienced raters graded the lesion severity on 3 T MRI and CBCT images: grade 1: no signs of a subchondral bone lesion; grade 2: subchondral trabecular fracture or cystic changes, but without infraction of the subchondral bone plate; grade 3: collapse of the subchondral bone plate. Ratings were repeated after six weeks to determine reliability. In addition, the bone lesion size was measured as elliptical area (mm2) and compared between CBCT and T1-weighted MRI sequences. Among 30 patients included (43.3% women; mean age: 60.9 ± 12.8 years; body mass index (BMI) 29.0 ± 12.8 kg/m2), the medial femoral condyle was affected in 21/30 patients (70%). The grading of subchondral lesions between MRI and CBCT did not match in 12 cases (40%). Based on MRI images, an underestimation (i.e., undergrading) compared with CBCT was observed in nine cases (30%), whereas overgrading occurred in three cases (10%). Compared to CBCT, routine T1-weighted 3 T sequences significantly overestimated osseus defect zones in sagittal (84.7 ± 68.9 mm2 vs. 35.9 ± 38.2 mm2, p < 0.01, Cohen’s d = 1.14) and coronal orientation (53.1 ± 24.0 mm2 vs. 22.0 ± 15.2 mm2, p < 0.01, Cohen’s d = 1.23). The reproducibility of the grading determined by intra- and inter-rater agreement was very high in MRI (intra-class correlation coefficient (ICC) 0.78 and 0.90, respectively) and CBCT (ICC 0.96 and 0.96, respectively). In patients with subchondral insufficiency fractures of the knee, the use of CBCT revealed discrepancies in lesion grading compared with MRI. These findings are clinically relevant, as precise determination of subchondral bone plate integrity may influence the decision about conservative or surgical treatment. CBCT represents our imaging modality of choice for grading the lesion and assessing subchondral bone plate integrity. MRI remains the gold standard modality to detect especially early stages.

Catathrenia is a rare disease, classified as isolated symptoms and normal variants under sleep-related breathing disorders in the International Classification of Sleep Disorders, third edition. Because of its rarity, the research on its pathogenesis and treatment is insufficient. This study aimed to evaluate whether the mandibular advancement device (MAD) could be considered an alternative treatment trial and if so, to explore factors predicting its effectiveness. Thirty patients (12 men and 18 women, aged 16-67 years) with catathrenia participated in the study. They underwent standard clinical evaluation, questionnaires, physical examinations, craniofacial evaluations, video polysomnography, and imaging of the upper airway before and after the insertion of the MAD. The groaning index (groaning episodes per hour of sleep) and apnea-hypopnea index were evaluated, and anatomic factors predicting effectiveness were explored. The sleep efficiency of most patients was higher than 80%, and groaning was present throughout all stages of sleep. With the insertion of the MAD, the groaning index decreased significantly from 5.8 (2.7-14.3) to 2.8 (1.3-12.2) events/h (P = .014). Age had a negative effect on efficacy. Mandibular repositioning of the MAD, especially the amount of vertical opening and changes of the cross-sectional area of the hypopharynx, was positively related with efficacy. The MAD could be considered a possible treatment trial for those seeking treatment for groaning. Registry: Chinese Clinical Trial Register; Name: The etiology of catathrenia based on oral and maxillofacial system; URL: http://www.chictr.org.cn/showproj.aspx?proj=22286; Identifier: ChiCTR-COC-17013239. Yu M, Hao Z, Xu L, Wen Y, Han F, Gao X. Mandibular advancement device as treatment trial for catathrenia (nocturnal groaning). J Clin Sleep Med. 2021;17(9):1767-1776.

BackgroundThe emergence of robotic Cone Beam Computed Tomography (CBCT) imaging systems in trauma departments has enabled 3D anatomical assessment of musculoskeletal injuries, supplementing conventional 2D fluoroscopic imaging for examination, diagnosis, and treatment planning. To date, the primary focus has been on trauma sites in the extremities.PurposeTo determine if CBCT images can be used during the treatment planning process in spinal instrumentation and laminectomy procedures, allowing accurate 3D‐printed pedicle screw and laminectomy drill guides to be generated for the cervical and thoracic spine.MethodsThe accuracy of drill guides generated from CBCT images was assessed using animal cadavers (ovine and porcine). Preoperative scans were acquired using a robotic CBCT C‐arm system, the Siemens ARTIS pheno (Siemens Healthcare, GmbH, Germany). The CBCT images were imported into 3D‐Slicer version 4.10.2 (www.slicer.org) where vertebral models and specific guides were developed and subsequently 3D‐printed. In the ovine cadaver, 11 pedicle screw guides from the T1–T5 and T7–T12 vertebra and six laminectomy guides from the C2–C7 vertebra were planned and printed. In the porcine cadaver, nine pedicle screw guides from the C3–T4 vertebra were planned and printed. For the pedicle screw guides, accuracy was assessed by three observers according to pedicle breach via the Gertzbein–Robbins grading system as well as measured mean axial and sagittal screw error via postoperative CBCT and CT scans. For the laminectomies, the guides were designed to leave 1 mm of lamina. The average thickness of the lamina at the mid‐point was used to assess the accuracy of the guides, measured via postoperative CBCT and CT scans from three observers. For all measurements, the intraclass correlation coefficient (ICC) was calculated to determine observer reliability.ResultsCompared with the planned screw angles for both the ovine and porcine procedures (n = 32), the mean axial and sagittal screw error measured on the postoperative CBCT scans from three observers were 3.9 ± 1.9° and 1.8 ± 0.8°, respectively. The ICC among the observes was 0.855 and 0.849 for the axial and sagittal measurements, respectively, indicating good reliability. In the ovine cadaver, directly comparing the measured axial and sagittal screw angle of the visible screws (n = 14) in the postoperative CBCT and conventional CT scans from three observers revealed an average difference 1.9 ± 1.0° in axial angle and 1.8 ± 1.0° in the sagittal angle. The average thickness of the lamina at the middle of each vertebra, as measured on‐screen in the postoperative CBCT scans by three observes was 1.6 ± 0.2 mm. The ICC among observers was 0.693, indicating moderate reliability. No lamina breaches were observed in the postoperative images.ConclusionHere, CBCT images have been used to generate accurate 3D‐printed pedicle screw and laminectomy drill guides for use in the cervical and thoracic spine. The results demonstrate sufficient precision compared with those previously reported, generated from standard preoperative CT and MRI scans, potentially expanding the treatment planning capabilities of robotic CBCT imaging systems in trauma departments and operating rooms.