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1.
Braz. j. oral sci ; 20: e211236, jan.-dez. 2021. ilus
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-1253730

RESUMO

Aim: Dental imaging has been widely used for diagnosis in dentistry. However, dental X-ray may induce cytotoxicity leading to apoptosis in oral mucosa cells. The present study aimed to observe the maturation pattern of buccal and gingival cells after exposure to X-ray radiation from analog/digital panoramic scanning and cone beam computed tomography (CBCT). Methods: The research samples were 40 subjects who fulfilled the inclusion and exclusion criteria. The subjects were divided into the exposed (patients who received analog/digital panoramic radiography or CBCT) and controlled (patients who had no radiography examinations) groups, with 10 subjects in each group. Exfoliative cytology smears were obtained from buccal mucosa and gingiva before exposure (or on day 0 for the control group) and 10 days later. The cells were stained with the Papanicolaou method. Then, the superficial, intermediate, and parabasal cells were counted in each glass slide. Results: No significant differences (p > 0.05) were observed among all cell types between day 0 and 10 in the control group. Meanwhile, after exposure to three kinds of radiography examinations, the frequency of intermediate cells in buccal mucosa and gingiva increased (p < 0.05), but that of superficial cells decreased (p < 0.05) significantly. No significant difference was found in the parabasal cells (p > 0.05). The frequency differences between intermediate and superficial cells showed no significant difference between the buccal mucosa and gingiva. Conclusion: Analog/digital panoramic radiography and CBCT exposure can induce cytotoxicity by altering the maturation pattern of buccal mucosa cells and gingiva, so it is strongly recommended to only perform these procedures if necessary and avoid repeated exposure to the same patient


Assuntos
Humanos , Radiografia Panorâmica , Tomografia Computadorizada de Feixe Cônico , Teste de Papanicolaou , Gengiva , Mucosa Bucal
2.
JNMA J Nepal Med Assoc ; 59(239): 649-652, 2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34508500

RESUMO

INTRODUCTION: C-shaped canal configuration is mostly found in the mandibular second molar. The morphological characteristic of a C-shaped canal is the presence of a fin or web connecting the individual canal, making it difficult for cleaning, shaping, and obturation. The objective of this study was to find out the prevalence of C-shaped canal in mandibular second molar among cases of Cone Beam Computed Tomography in tertiary care centres. METHODS: The descriptive cross-sectional study was conducted in the department of conservative dentistry and endodontics of tertiary care centres from 20th June 2020 to 20th December 2020 after receiving ethical approval from the Nepal Health Research Council on 19 June 2020. Cone-beam computed tomography images of 199 mandibular second molars with completely formed roots were used. Teeth with orthodontic braces, root resorption, root canal filling, and post were excluded from the study. The research was conducted taking a tooth as a unit. Convenience sampling was done. Statistical analysis was done by using Statistical Package for Social Sciences version 16. Point estimate at 95% Confidence Interval was calculated along with frequency and proportion for binary data. RESULTS: The prevalence of C-shaped canal according to this study is 25 (12.6%) (7.99-17.21 at 95% Confidence Interval). CONCLUSIONS: The findings of the study conclude that C-shaped configuration is quite frequent in mandibular second molar among cases of Cone Beam Computed Tomography. A careful pre-operative radiographic evaluation may be helpful for diagnosing C-shaped configuration prior to root canal treatment.


Assuntos
Mandíbula , Raiz Dentária , Tomografia Computadorizada de Feixe Cônico , Estudos Transversais , Humanos , Mandíbula/diagnóstico por imagem , Centros de Atenção Terciária
3.
Georgian Med News ; (316-317): 96-102, 2021.
Artigo em Russo | MEDLINE | ID: mdl-34511453

RESUMO

The aim of this study was to assess the dynamics of changes of the transversal dimensions of upper jaw at different levels following rapid maxillary expansion in child cases during the mixed dentition period according to the medium field of view (FOV) of Cone-Beam Computed Tomography (CBCT). Thirty-seven children aged 7 to 12 were included in this study. The median age was 8.9 years. All patients underwent rapid palatal expansion with the appliance for rapid maxillary expansion (RME) according to orthodontic indications. For each case, cone beam computed tomography (CBCT) data was obtained and evaluated before orthodontic treatment and three to six months after completion of maxillary expansion. Determination of anatomical landmarks and linear transversal measurements of the upper jaw at different levels were carried out using the i-CAT Vision software. The transversal dimensions of the upper jaw were measured, the linear dimensions of the width of the dental, alveolar and basal arch were estimated at the molar level, and at the level of the floor of the nasal cavity exectly between the large palatine canals and at the level of pyriform aperture on the CBCT images obtained before treatment and after rapid maxillary expansion. The greatest maxilla transversal expansion was observed on the level of dental arch and pyriform aperture, on average in 7.1% and 6.03% respectively. The smallest increase in the transversal dimensions of the upper jaw after RME was observed on the level of vestibular cortical plate of the first permanent molars as well as on the level of the centre of molar resistance (on average 3.7%). CBCT data makes it possible to reliably assess the dynamics of changes in the transversal dimensions of the upper jaw at different levels during the mixed dentition following RME, as well as to assess the expansion of the upper jaw at the level of the floor of the nasal cavity. This, in turn, can affect the characteristics of the airflow at the nasal level.


Assuntos
Técnica de Expansão Palatina , Tomografia Computadorizada de Feixe Cônico Espiral , Tomografia Computadorizada de Feixe Cônico , Dentição Mista , Humanos , Maxila/diagnóstico por imagem
4.
Shanghai Kou Qiang Yi Xue ; 30(3): 273-277, 2021 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-34476444

RESUMO

PURPOSE: To study the changes of dimension and morphology of upper airway in children with ClassⅡ mandibular retrusion after functional treatment by sagittal-guidance Twin-block appliance. METHODS: Cone-beam CT (CBCT) data of upper airway of the subjects were measured by Dolphin 11.5 software and Mimics 17.0 software , and the changes of dimension and morphology of upper airway before and after functional treatment with sagittal-guidance Twin-block(SGTB) appliance were compared. SPSS 16.0 software package was used for data processing. RESULTS: After functional treatment,the volume of total upper airway,nasopharynx airway, oropharynx airway, the sectional area of tip of the epiglotti(TE), the lateral diameter of TE, the base of the epiglottis(EB) significantly increased (P<0.05) in children with SGTB appliance. CONCLUSIONS: SGTB functional treatment is effective in the treatment of skeletal ClassⅡ mandibular retrusion of children by increase of the upper airway and improvement of respiration..


Assuntos
Má Oclusão Classe II de Angle , Micrognatismo , Retrognatismo , Cefalometria , Criança , Tomografia Computadorizada de Feixe Cônico , Humanos , Má Oclusão Classe II de Angle/diagnóstico por imagem , Má Oclusão Classe II de Angle/terapia , Ronco
5.
Shanghai Kou Qiang Yi Xue ; 30(3): 316-322, 2021 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-34476453

RESUMO

PURPOSE: To analyze the opening of mid-palatal suture, transverse changes in dental and dentoalveolar measurements and shift of midfacial bony structures induced by maxillary skeletal expansion (MSE) with cone-beam CT (CBCT), and to evaluate the effect of maxillary skeletal expansion and its influence on adjacent bony structures in adults. METHODS: The study sample consisted of 12 adult patients with maxillary transverse deficiency (4 males, 8 females) at a mean age of (21.17±4.13) years old. All patients were treated with MSE. After treatment, the posterior crossbite was corrected, and the width of the maxillary arch was achieved the optimal width. Pre- and post-treatment CBCT exams were taken before and after MSE treatment. Multiplanar coronal and axial slices obtained from CBCT images were used to measure the changes in transverse widths, angular changes and tooth inclination with Dolphin Imaging 11.9. SPSS 26.0 software package was used for statistical analysis. RESULTS: After MSE treatment, the anterior nasal spine width increased by (2.38±1.01) mm, posterior nasal spine width increased by (2.25±1.08) mm (P<0.01). The inter-crown and inter-apex distance at the first molar increased by (5.56±1.38) mm and (4.14±1.29) mm, respectively (P<0.01). No significant difference was seen in terms of tooth inclination of the first molar(P>0.05). Pterygoid process angle, pterygoid process width, anterior inter-maxillary distance, upper and lower inter-zygomatic distance were significantly larger after treatment (P<0.01), while the inter-temporal distance and bilateral zygomaticomaxillary angle remained unchanged(P>0.05). CONCLUSIONS: MSE has a favorable effect in adult patients with parallel skeletal expansion of the mid-palatal suture achieved after expansion. The teeth present with certain buccal inclination but show no significant movement relative to the alveolar bone. The midfacial bony structures also shift in three-dimensional under the effect of the expansion force.


Assuntos
Técnica de Expansão Palatina , Palato , Adulto , Tomografia Computadorizada de Feixe Cônico , Feminino , Humanos , Masculino , Maxila/diagnóstico por imagem , Suturas
6.
Chin J Dent Res ; 24(3): 177-183, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34491012

RESUMO

OBJECTIVE: To assess the prevalence, location, diameter, course and anastomosis of the lateral lingual foramina (LLF) and canals (LLCs) in a northern Chinese population using CBCT. METHODS: CBCT images of 506 patients (181 male and 325 female, mean age 21.03 ± 8.11 years) were collected. The prevalence, location, diameter, length, angle and anastomosis of the LLF and LLCs were assessed. The measurement variables were analysed by sex and age. Statistical analysis was performed using SPSS (v. 25, IBM, Armonk, NY, USA). RESULTS: A total of 461 LLF were detected in 307 (60.7%) subjects, 175 (57.0%) of whom had unilateral LLF and 132 (43.0%) of whom had bilateral LLF, with each lateral having one to four LLF. The majority of LLF (375/461, 81.3%) were located below the premolars, particularly the first premolar. The mean diameter of the LLF was 0.58 ± 0.20 mm. The mean vertical distance from the LLF to the inferior border and the alveolar crest was 6.68 ± 1.43 mm and 23.65 ± 2.89 mm, respectively. In total, 197 LLCs were visible in the cancellous bone and evaluated. The mean length of LLCs was 6.26 ± 1.29 mm, and the mean angle of LLCs was 140.64° ± 17.29°. The overwhelming majority (93.4%) of LLCs communicated with the mandibular incisive canal and the rest connected with the mandibular canal. CONCLUSION: The prevalence of LLCs was high in the northern Chinese population. The presence of LLCs is a significant predictor of communication with the mandibular incisive canal.


Assuntos
Tomografia Computadorizada de Feixe Cônico Espiral , Adolescente , Adulto , Processo Alveolar , Criança , China , Tomografia Computadorizada de Feixe Cônico , Feminino , Humanos , Masculino , Mandíbula/diagnóstico por imagem , Adulto Jovem
7.
Head Face Med ; 17(1): 33, 2021 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-34389020

RESUMO

BACKROUND: This study was designed to analyse the value of preoperative Cone Beam CTs (CBCT) prior to the surgical removal of complex lower third molars. Furthermore, the aim was to assess injuries to the inferior alveolar nerve (IAN) bundle and postoperative neurological disorders depending on the position of the lower third molar and the inferior alveolar nerve bundle. METHODS: In this retrospective examination preoperative Cone Beam CTs and Orthopantomographs (OPT) of 324 patients were analysed concerning the location of the lower third molars in relation to the mandible and the inferior alveolar nerve bundle. Surgery protocols of all patients who underwent the surgical removal of at least one complex lower third molar were analysed concerning patient data, length of surgery, intraoperative haemorrhage, intraoperative exposure of the inferior alveolar nerve bundle, postoperative swelling and postoperative neurological disorders. The data was then compared to data from international studies. RESULTS: In all 324 patients a permanent neurological damage was not found. Temporary neurological damage was recorded in 13 cases (2.6%). A caudal nerve position with no measurable distance to the root of the lower third molar was associated with the highest risk of a temporal neurological damage. A vestibular touching nerve route also correlated with postoperative sensitivity impairment. If a mesioangulation (Winter) or a Pell and Gregory Type IIIC appears in the OPT, risk of neurological damage is at its highest. CONCLUSIONS: Three-dimensional radiographic imaging, in our patient group, does not significantly affect the risk for complications during the surgical removal of complex lower third molars. Therefore, it should only be utilized for risk assessment, especially in cases of symptom-free lower third molars. A preoperative orthopantomogram still can be accepted as standard for radiographic imaging. An intraoperative exposure of the IAN bundle does not necessarily predict simultaneous neurological damage. Exposure of the IAN bundle is no indication for a discontinuation of the surgery.


Assuntos
Dente Impactado , Traumatismos do Nervo Trigêmeo , Tomografia Computadorizada de Feixe Cônico , Humanos , Mandíbula/diagnóstico por imagem , Mandíbula/cirurgia , Nervo Mandibular/diagnóstico por imagem , Dente Serotino/diagnóstico por imagem , Dente Serotino/cirurgia , Radiografia Panorâmica , Estudos Retrospectivos , Extração Dentária/efeitos adversos , Dente Impactado/diagnóstico por imagem , Dente Impactado/cirurgia , Traumatismos do Nervo Trigêmeo/prevenção & controle
8.
J Contemp Dent Pract ; 22(6): 599-604, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34393113

RESUMO

AIMS AND OBJECTIVES: To evaluate the correlation between the curve of Spee (COS) of a patient and the Collum angle of mandibular anterior dentition using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: This cross-sectional study was based on the analysis of 100 CBCTs of patients divided sagittally into two separate subjects. The Collum angles of the mandibular central incisor, mandibular lateral incisor, and the mandibular canine were measured along with the COS of that quadrant using Dolphin Imaging. A multivariate linear regression and Pearson correlation coefficients were conducted to measure the correlation between the COS and the Collum angle of mandibular anterior dentition. RESULTS: The total number of participants in the cohort was 200 samples out of 100 patients as this was a split mouth study. The mean COS was 2.09 ± 1.239 mm. The mean Collum angle of the mandibular central incisor (L1) was found to be 6.50 ± 3.002 degrees. The mean Collum angle of the mandibular lateral incisor (L2) was 7.19 ± 2.554 degrees and the mean Collum angle of the mandibular canine (L3) was 7.03 ± 2.907 degrees. There was a statistically significant moderate correlation between L1, L2, and L3 and the COS with the Collum angle of the mandibular central incisor most highly correlated to the COS (0.42), followed by the mandibular lateral incisor (0.35) and then the mandibular canine (0.30). CONCLUSIONS: There is a statistically significant low to moderate correlation between the COS and the Collum angles of the mandibular anterior dentition.


Assuntos
Tomografia Computadorizada de Feixe Cônico , Maxila , Estudos Transversais , Dente Canino/diagnóstico por imagem , Humanos , Incisivo/diagnóstico por imagem
9.
Pol Merkur Lekarski ; 49(292): 286-289, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34464370

RESUMO

AIM: The aim of the study was to assess bone resorption in patients with chronic generalized periodontitis according to orthopantomogram (OP) and cone-beam computed tomography (CBCT) and substantiate which of these methods is the most appropriate for use. MATERIALS AND METHODS: In order to compare the objectivity of the results of examining the periodontal bone tissue by the above methods (panoramic radiography and computed tomography), we analyzed 26 panoramic radiographs and computed tomograms of the same patients, performed on a PICASSO (3D) computed tomograph by «Vatech¼. RESULTS: Comparison of CBCT and OP data in patients with periodontal tissue disease showed a significant difference between the indicators of bone tissue resorption in the mesiodistal direction, and revealed that the volumetric image is significantly objective X-ray picture in periodontal diseases by identifying the state (resorption) of the vestibular and oral cortical plates in any section dentition. At the same time, only according to CBCT data, an objective assessment of bone resorption in the vestibulo-oral direction is likely. CONCLUSIONS: Mesiodistal CT and orthopantomographic data do not match well enough. They allow with high accuracy to identify areas of resorption only from the medial and distal sides. However, the vestibulooral CT projection indicates the bias of a two-dimensional image for obtaining an accurate X-ray picture of the state of the alveolar bone and a complete assessment of bone resorption.


Assuntos
Reabsorção Óssea , Periodontite , Reabsorção Óssea/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico , Humanos , Maxila , Radiografia Panorâmica
10.
Int J Oral Maxillofac Implants ; 36(4): 731-736, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34411213

RESUMO

PURPOSE: The objective of this study was to identify the highly cited references that drove the research on implant dentistry with CBCT. MATERIALS AND METHODS: The literature database Web of Science Core Collection was accessed to identify a collection of papers on this theme. Cited reference analysis was conducted with the aid of CRExplorer, dedicated bibliometric software. RESULTS: The analysis succeeded in identifying the papers that introduced the very first CBCT machines in the Asian and European markets, respectively; papers that proved the CBCT measurement accuracy, its ability to visualize sinus floor penetration, and its reduced metal artifact relative to conventional CT; papers that gave imaging guidelines for implant cases; and papers reporting bone remodeling at extraction sockets and the possibility of grafting at sites with inadequate bone. CONCLUSION: These publications together provided solid evidence to support subsequent dental implant research and evaluation by CBCT.


Assuntos
Implantes Dentários , Levantamento do Assoalho do Seio Maxilar , Tomografia Computadorizada de Feixe Cônico Espiral , Bibliometria , Remodelação Óssea , Tomografia Computadorizada de Feixe Cônico , Humanos
11.
Gen Dent ; 69(5): 57-61, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34424214

RESUMO

The finding of medial arterial calcification (MAC) on cone beam computed tomographic scans is more common than many clinicians realize. Medial arterial calcification is a specific pattern of vascular calcification that has been associated with diabetes mellitus. When MAC is identified on a scan, the clinician must refer the patient for evaluation of cardiovascular accident risk and for serologic evaluation to detect undiagnosed type 2 diabetes mellitus. This case report describes a patient with undiagnosed type 2 diabetes mellitus that was later confirmed by hemoglobin A1c levels after incidental detection of MAC on cone beam computed tomography. The article also reviews the literature on MAC and its relationship with diabetes and discusses radiographic features of MAC that are often unrecognized by clinicians.


Assuntos
Diabetes Mellitus Tipo 2 , Tomografia Computadorizada de Feixe Cônico Espiral , Tomografia Computadorizada de Feixe Cônico , Diabetes Mellitus Tipo 2/complicações , Hemoglobina A Glicada , Humanos
12.
J Forensic Odontostomatol ; 2(39): 2-14, 2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-34419940

RESUMO

INTRODUCTION: Forensic dentistry has, as one of its main goals, the identification of living and/or deceased individuals, based on the individual features of the teeth. One of the identification criteria to be established is the chronological age. Several authors, including Kvaal, have developed age estimation methods based on secondary dentine deposition. Nowadays, three-dimensional imaging tests, such as Cone Beam Computed Tomography (CBCT), are used in age estimation. OBJECTIVE: The aims of this research project were to validate Kvaal's method and its variables in age estimation and to create new linear regression formulae to better represent the study sample. METHODS: We selected 158 CBCT, with a total of 402 sound teeth (central incisors, lateral incisors and canines). The necessary measurements and ratios were calculated in both coronal and sagittal sections, with XelisDental . The formulae developed by Kvaal for age estimation calculation were applied. Subsequently, the results were statistically analyzed. RESULTS AND DISCUSSION: The intraclass correlation coefficients from the two measurements ranged from 0.918 to 0.997. The calculated age estimation had a mean error of -21.4years (coronal section) and -26.3years (sagittal section). The t test revealed statistically significant differences between chronological age and estimated age. The absolute values of Pearson's correlation coefficient between age and the two Kvaal variables ranged from 0.06 to 0.38 and from 0.06 to 0.55. The coefficients of determination are lower than in the original study (between 0.03 and 0.39). In the linear regression formulae, the coefficients of determination ranged from 0.07 to 0.41. CONCLUSION: This investigation concludes a non-reproducibility of Kvaal's method in the Portuguese population when applied in CBCT, with statistically significant differences between the chronological age and the dental age, estimated by the pulp/ tooth proportion method, based on the teeth analyzed in this study.


Assuntos
Determinação da Idade pelos Dentes , Tomografia Computadorizada de Feixe Cônico , Polpa Dentária/diagnóstico por imagem , Odontologia Legal , Humanos , Incisivo
13.
Medicina (Kaunas) ; 57(8)2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34441046

RESUMO

Background and Objectives: Odontogenic sinusitis is a frequently underestimated pathology with fewer symptoms in patients with periapical lesions, periodontal disease, or iatrogenic foreign bodies in the maxillary sinus. The aim of our study was to determine the correlation between maxillary sinusitis and periapical lesions using cone-beam computed tomography (CBCT) imaging and histological and immunohistochemical investigations. Materials and Methods: A total of 1450 initial patients diagnosed with maxillary sinusitis in the Ear-Nose-Throat (ENT) Department, University of Medicine and Pharmacy "Grigore T. Popa" Iasi, Romania, were treated with anti-inflammatory drugs. Of these, 629 still had unresolved symptomatology and were later referred to the Dental Medicine departments for further investigations. Only 50 subjects with periapical lesions in the premolar/molar maxillary area were included in the present study. All the periapical lesions were observed on CBCT and classified using the Periapical Status Index (PSI) and the mean maxillary sinus mucosa thicknesses (MSMT). The enrolled patients underwent surgical procedures with the excision of periapical lesions. The excised samples were submitted to the histological and immunohistochemical investigations. Results: The 50 patients presented periapical lesions of their maxillary teeth in 328 dental units. There was a higher prevalence of periapical lesions in men than in women (chi-square test). We observed a significant difference between the mean MSMT of individuals with periapical lesions compared to those without (p < 0.01). Mean MSMT was 1.23 mm for teeth without periapical lesions and 3.95 mm for teeth with periapical lesions. The histopathological study identified 50% cases with periapical granulomas, 10% cases with periapical granulomas with cystic potential, and 40% cases as periapical cysts. Immunohistochemical stainings showed that CD4+ helper and CD8+ cytotoxic T lymphocytes, along with CD20+ B lymphocytes and CD68+ macrophages, were diffusely distributed in all periapical cysts and in some periapical granulomas, but CD79α+ plasma cells characterized especially periapical granulomas. Conclusions: The current study observed a significant correlation between CBCT maxillary mucosa thickness and type of periapical lesion. Chronic inflammatory lympho-histiocytic infiltrate predominates in periapical lesions, supporting the idea that lesion progression is determined by a humoral-type (CD20+ and CD79α+ B lymphocytes) but also by a cellular-type (CD4+ and CD8+ T lymphocyte population) immune mechanism.


Assuntos
Seio Maxilar , Sinusite Maxilar , Tomografia Computadorizada de Feixe Cônico , Feminino , Humanos , Masculino , Seio Maxilar/diagnóstico por imagem , Sinusite Maxilar/diagnóstico por imagem , Dente Molar , Membrana Mucosa
14.
J Appl Clin Med Phys ; 22(9): 271-279, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34375008

RESUMO

PURPOSE: We evaluated the effect of changing the scan mode of the Elekta X-ray volume imaging cone beam computed tomography (CBCT) on the accuracy of dose calculation, which may be affected by computed tomography (CT) value errors in three dimensions. METHODS: We used the electron density phantom and measured the CT values in three dimensions. CT values were compared with planning computed tomography (pCT) values for various materials. The evaluated scan modes were for head and neck (S-scan), chest (M-scan), and pelvis (L-scan) with various collimators and filter systems. To evaluate the effects of the CT value error of the CBCT on dose error, Monte Carlo calculations of dosimetry were performed using pCT and CBCT images. RESULTS: The L-scan had a CT value error of approximately 800 HU at the isocenter compared with the pCT. Furthermore, inhomogeneity in the longitudinal CT value profile was observed in the bone material. The dose error for ±100 HU difference in CT values for the S-scan and M-scan was within ±2%. The center of the L-scan had a CT error of approximately 800 HU and a dose error of approximately 6%. The dose error of the L-scan occurred in the beam path in the case of both single field and two parallel opposed fields, and the maximum error occurred at the center of the phantom in the case of both the 4-field box and single-arc techniques. CONCLUSIONS: We demonstrated the three-dimensional CT value characteristics of the CBCT by evaluating the CT value error obtained under various imaging conditions. It was found that the L-scan is considerably affected by not having a unique bowtie filter, and the S-scan without the bowtie filter causes CT value errors in the longitudinal direction. Moreover, the CBCT dose errors for the 4-field box and single-arc irradiation techniques converge to the isocenter.


Assuntos
Tomografia Computadorizada de Feixe Cônico , Tomografia Computadorizada por Raios X , Humanos , Imagens de Fantasmas , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Raios X
15.
J Appl Clin Med Phys ; 22(9): 37-48, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34378308

RESUMO

PURPOSE: We performed quantitative analysis of differences in deformable image registration (DIR) and deformable dose accumulation (DDA) computed on CBCT datasets reconstructed using the standard (Feldkamp-Davis-Kress: FDK_CBCT) and a novel iterative (iterative_CBCT) CBCT reconstruction algorithms. METHODS: Both FDK_CBCT and iterative_CBCT images were reconstructed for 323 fractions of treatment for 10 prostate cancer patients. Planning CT images were deformably registered to each CBCT image data set. After daily dose distributions were computed, they were mapped to planning CT to obtain deformed doses. Dosimetric and image registration results based CBCT images reconstructed by two algorithms were compared at three levels: (A) voxel doses over entire dose calculation volume, (B) clinical constraint results on targets and sensitive structures, and (C) contours propagated to CBCT images using DIR results based on three algorithms (SmartAdapt, Velocity, and Elastix) were compared with manually delineated contours as ground truth. RESULTS: (A) Average daily dose differences and average normalized DDA differences between FDK_CBCT and iterative_CBCT were ≤1 cGy. Maximum daily point dose differences increased from 0.22 ± 0.06 Gy (before the deformable dose mapping operation) to 1.33 ± 0.38 Gy after the deformable dose mapping. Maximum differences of normalized DDA per fraction were up to 0.80 Gy (0.42 ± 0.19 Gy). (B) Differences in target minimum doses were up to 8.31 Gy (-0.62 ± 4.60 Gy) and differences in critical structure doses were 0.70 ± 1.49 Gy. (C) For mapped prostate contours based on iterative_CBCT (relative to standard FDK_CBCT), dice similarity coefficient increased by 0.10 ± 0.09 (p < 0.0001), mass center distances decreased by 2.5 ± 3.0 mm (p < 0.00005), and Hausdorff distances decreased by 3.3 ± 4.4 mm (p < 0.00015). CONCLUSIONS: The new iterative CBCT reconstruction algorithm leads to different mapped volumes of interest, deformed and cumulative doses than results based on conventional FDK_CBCT.


Assuntos
Tomografia Computadorizada de Feixe Cônico Espiral , Algoritmos , Tomografia Computadorizada de Feixe Cônico , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Radiometria , Planejamento da Radioterapia Assistida por Computador
16.
J Appl Clin Med Phys ; 22(9): 215-226, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34406710

RESUMO

BACKGROUND AND PURPOSE: When treating lung tumors with stereotactic body radiation therapy (SBRT), patient immobilization is of outmost importance. In this study, the intra-fractional shifts of the patient (based on bony anatomy) and the tumor (based on the visible target volume) are quantified, and the associated impact on the delivered dose is estimated for a frameless immobilization approach in combination with surface guided radiation therapy (SGRT) monitoring. METHODS: Cone beam computed tomographies (CBCT) were collected in free breathing prior and after each treatment for 25 patients with lung tumors, in total 137 fractions. The CBCT collected after each treatment was registered to the CBCT collected before each treatment with focus on bony anatomy to determine the shift of the patient, and with focus on the visible target volume to determine the shift of the tumor. Rigid registrations with 6 degrees of freedom were used. The patients were positioned in frameless immobilizations with their position and respiration continuously monitored by a commercial SGRT system. The patients were breathing freely within a preset gating window during treatment delivery. The beam was automatically interrupted if isocenter shifts >4 mm or breathing amplitudes outside the gating window were detected by the SGRT system. The time between the acquisition of the CBCTs was registered for each fraction to examine correlations between treatment time and patient shift. The impact of the observed shifts on the dose to organs at risk (OAR) and the gross tumor volume (GTV) was assessed. RESULTS: The shift of the patient in the CBCTs was ≤2 mm for 132/137 fractions in the vertical (vrt) and lateral (lat) directions, and 134/137 fractions in the longitudinal (lng) direction and ≤4 mm in 134/137 (vrt) and 137/137 (lat, lng) of the fractions. The shift of the tumor was ≤2 mm in 116/137 (vrt), 123/137 (lat) and 115/137 (lng) fractions and ≤4 mm in 136/137 (vrt), 137/137 (lat), and 135/137 (lng) fractions. The maximal observed shift in the evaluated CBCT data was 4.6 mm for the patient and 7.2 mm for the tumor. Rotations were ≤3.3ᵒ for all fractions and the mean/standard deviation were 0.2/1.0ᵒ (roll), 0.1/0.8ᵒ (yaw), and 0.3/1.0ᵒ (pitch). The SGRT system interrupted the beam due to intra-fractional isocenter shifts >4 mm for 21% of the fractions, but the patients always returned within tolerance without the need of repositioning. The maximal observed isocenter shift by the SGRT system during the beam holds was 8 mm. For the respiration monitoring, the beam was interrupted at least one time for 54% of the fractions. The visual tumor was within the planned internal target volume (ITV) for 136/137 fractions in the evaluated CBCT data collected at the end of each fraction. For the fraction where the tumor was outside the ITV, the D98% for the GTV decreased with 0.4 Gy. For the OARs, the difference between planned and estimated dose from the CBCT data (D2% or Dmean ) was ≤2.6% of the prescribed PTV dose. No correlation was found between treatment time and the magnitude of the patient shift. CONCLUSIONS: Using SGRT for motion management and respiration monitoring in combination with a frameless immobilization is a feasible approach for lung SBRT.


Assuntos
Neoplasias Pulmonares , Radiocirurgia , Radioterapia Guiada por Imagem , Tomografia Computadorizada de Feixe Cônico , Humanos , Pulmão , Neoplasias Pulmonares/radioterapia , Neoplasias Pulmonares/cirurgia , Movimento , Planejamento da Radioterapia Assistida por Computador
17.
Arch Oral Biol ; 130: 105242, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34411883

RESUMO

OBJECTIVE: To determine the frequency of taurodontism in maxillary and mandibular molar teeth using cone-beam computed tomography (CBCT) and to compare the differences in root and canal morphologies between taurodont and nontaurodont molars. METHODS: CBCT images of 1200 patients were analysed. First, the frequency of taurodontism in maxillary and mandibular molar teeth was calculated. The Shifman and Chanannel taurodontic index was used to diagnose taurodontic teeth. Subsequently, the root and canal morphologies were compared with those of 250 normal teeth randomly selected from each tooth group. P < 0.05 values were considered significant in statistical tests. The chi-square test was used for differences according to sex, age and tooth position. Z-test was used for comparing percentages between independent groups. RESULTS: The occurrence rate of taurodontism was 7.78 % and 12.72 % in maxillary first and second molar teeth, respectively, and 1.99 % and 2.41 % in mandibular first and second molar teeth, respectively. Women had more taurodont teeth than men. The frequency of root fusion was greater in taurodont maxillary molars. The percentage of C-shaped roots in taurodont mandibular second molars was significantly higher than in cynodonts (19.15 % and 8.4 %, respectively). CONCLUSIONS: Taurodont teeth show wide variations in root and canal morphology. The degree of change in morphology is associated with the severity of taurodontism.


Assuntos
Dente Molar , Raiz Dentária , Tomografia Computadorizada de Feixe Cônico , Cavidade Pulpar/anormalidades , Feminino , Humanos , Masculino , Dente Molar/diagnóstico por imagem , Estudos Retrospectivos , Anormalidades Dentárias , Raiz Dentária/diagnóstico por imagem
18.
Eur J Radiol ; 142: 109878, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34388626

RESUMO

PURPOSE: To utilize a neural architecture search (NAS) approach to develop a convolutional neural network (CNN) method for distinguishing benign and malignant lesions on breast cone-beam CT (BCBCT). METHOD: 165 patients with 114 malignant and 86 benign lesions were collected by two institutions from May 2012 to August 2014. The NAS method autonomously generated a CNN model using one institution's dataset for training (patients/lesions: 71/91) and validation (patients/lesions: 20/23). The model was externally tested on another institution's dataset (patients/lesions: 74/87), and its performance was compared with fine-tuned ResNet-50 models and two breast radiologists who independently read the lesions in the testing dataset without knowing lesion diagnosis. RESULTS: The lesion diameters (mean ± SD) were 18.8 ± 12.9 mm, 22.7 ± 10.5 mm, and 20.0 ± 11.8 mm in the training, validation, and external testing set, respectively. Compared to the best ResNet-50 model, the NAS-generated CNN model performed three times faster and, in the external testing set, achieved a higher (though not statistically different) AUC, with sensitivity (95% CI) and specificity (95% CI) of 0.727, 80% (66-90%), and 60% (42-75%), respectively. Meanwhile, the performances of the NAS-generated CNN and the two radiologists' visual ratings were not statistically different. CONCLUSIONS: Our preliminary results demonstrated that a CNN autonomously generated by NAS performed comparably to pre-trained ResNet models and radiologists in predicting malignant breast lesions on contrast-enhanced BCBCT. In comparison to ResNet, which must be designed by an expert, the NAS approach may be used to automatically generate a deep learning architecture for medical image analysis.


Assuntos
Aprendizado Profundo , Mama , Tomografia Computadorizada de Feixe Cônico , Humanos , Redes Neurais de Computação , Radiologistas
19.
Medicine (Baltimore) ; 100(34): e27096, 2021 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-34449515

RESUMO

ABSTRACT: To determine the normal range of pancreatic volume (PV) in Chinese adults using computed tomography (CT) volumetry. To assess the relationships of PV with patient demographics and clinical parameters. To analyze the degree of correlation between PV values determined by manual segmentation and those calculated by formulas.A total of 240 adults (120 women, 120 men) between the ages of 18 and 79 years were reviewed. There were 6 groups of patients, with 40 patients in each decade regarding age. PV was segmented manually on computed tomography images slice by slice for each patient, and 2 formulas were used to calculate PV∗ and PV#.The mean PV was 77.44 ±â€Š19.11 cm3 (range from 28.55-138.15 cm3). PV was significantly correlated with height (r = 0.427, P < .001), weight (r = 0.525, P < .001), body mass index (r = 0.377, P < .001), the width of the first lumbar vertebral body (r = 0.166, P = .01), the transverse abdominal diameter (r = 0.455, P < .001), and the sagittal abdominal diameter (r = 0.456, P < .001). There was a negative correlation between PV and age (r = -0.209, P = .001). The correlation coefficients between PV and PV∗ and PV# were 0.676 and 0.376, respectively, with both P < .001.PV associated with patient demographics and clinical parameters. A more accurate and simpler formula should be used in the future to calculate and monitor changes in PV.


Assuntos
Algoritmos , Tomografia Computadorizada de Feixe Cônico/métodos , Tamanho do Órgão , Pâncreas/anatomia & histologia , Adolescente , Adulto , Fatores Etários , Idoso , Índice de Massa Corporal , China , Tomografia Computadorizada de Feixe Cônico/normas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valores de Referência , Fatores Sexuais , Fatores Socioeconômicos , Adulto Jovem
20.
Med Oral Patol Oral Cir Bucal ; 26(5): e598-e601, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34415002

RESUMO

BACKGROUND: Successful removal of salivary stones depends on exact pretreatment information of the location, the size and shape of the stones. This study aimed to compare the volume of submandibular sialoliths determined by preoperative Cone-Beam Computer Tomography (CBCT) scans with the volume of the removed stones on micro-Computer Tomography (micro-CT) scans. MATERIAL AND METHODS: In this study, using twenty-one submandibular sialoliths, the pretreatment volumes in-vivo measured on CBCT were compared to the volumes of removed stones determined by micro-CT scans. The volume measured on micro-CT scans served as the gold standard. Pre-operative CBCT's and in-vitro micro-CT's were converted into standard tessellation language models (STL-models) using an image segmentation software package. The CBCT and micro-CT images of the stones were subsequently metrologically assessed and compared to each other using reverse engineering software. RESULTS: Volumes of submandibular sialoliths determined by CBCT's correlated significantly with volumes measured on micro-CT's (Spearman's coefficient r = 0.916). The interquartile range (IQR) for the volume measured with micro-CT was 117.23. The median is 26.41. For the volume measured with CBCT the IQR was 141.3 and the median 36.61. The average volume on micro-CT is smaller than on CBCT. CONCLUSIONS: When using CBCT-scans for the detection of submandibular sialoliths one should realize that in-vivo those stones are actually a fraction smaller than assessed on the preoperative scan. This is important when cut-off values of sizes of stones are used in the pretreatment planning of stone removal.


Assuntos
Cálculos das Glândulas Salivares , Computadores , Tomografia Computadorizada de Feixe Cônico , Humanos , Cálculos das Glândulas Salivares/diagnóstico por imagem
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