Dental age estimation by assessing the pulp volume of five teeth in a peruvian population using cone beam computed tomography images / Estimación de la edad dental evaluando el volumen pulpar de cinco dientes utilizando imágenes de tomografías computarizadas de haz cónico en una población peruana

Abstract Dental age estimation is very important for individual identification in criminal and civil forensic investigations. One of the methods for age estimation is studying age related changes in pulp volume of teeth. The objective of the current study was to estimate dental age from the pulp volume of five different categories of teeth of a Peruvian sample using cone beam computed tomography (CBCT). Retrospective CBCT records of 231 patients (females (134), males (97), age: 12-60 years) were included in the study, categorized into five different age groups (12-19, 20-29, 30-39, 40-49, 50-59, 60 years and older). Dental pulp volume of five categories of teeth(upper canines, left upper central incisors, left upper first molars, lower left first premolars, first molars) were analyzed using Romexis® 5.3.3.5 software for each patient. There was a reduction in the pulp volume of upper right and left canine with age. The Pulp volume was lowest in people aged 60 years and over. Linear regression analysis of the pulp volume and chronological age showed a coefficient of determination of 30%, suggesting a weak correlation. A weak correlation between dental pulp and age is derived. But, a robust large homogenous sample of teeth in future for different age groups may establish a reliable regression equation.

Resumen La estimación de la edad dental en personas vivas y cadáveres es muy importante para la Odontología Forense, sobre todo en casos de identificación en investigaciones legales y sociales. El objetivo del estudio fue estimación de la edad dental mediante la medición del volumen pulpar de imágenes dentales en tomografía computarizada de haz cónico (TCHC) de pacientes peruanos. Fueron analizadas 231 TCHC de pacientes entre 12 a 60 años a más. (Mujeres (134), hombres (97)) se dividieron en seis grupos de edad (12-19, 20-29, 30-39, 40-49, 50-59, 60 años a más). El análisis volumétrico de la pulpa dental se realizó en un total de 1155 dientes (caninos superiores, incisivos centrales superiores izquierdos, primeros molares superiores izquierdos y primeros premolares inferiores izquierdos), mediante el software Romexis® 5.3.3.5. El análisis de regresión lineal mostró un coeficiente de determinación del 30% que sugiere una correlación débil entre la relación del volumen pulpar de los dientes y la edad. El volumen pulpar de los caninos superiores derecho e izquierdo disminuyó a medida que aumentaba la edad y el volumen pulpar en dientes de personas de 60 años a más fue el más bajo. Sin embargo, se pueden proponer estudios futuros para incluir una gran muestra homogénea de dientes en diferentes categorías y grupos de edad para confirmar la correlación y establecer una ecuación de regresión confiable.

Volumetric evaluation of CT images of adrenal glands in primary aldosteronism.

OBJECTIVES: To investigate whether adrenal volumetry provides better agreement with adrenal vein sampling (AVS) than conventional CT for subtyping PA. Furthermore, we evaluated whether the size of this contralateral adrenal was a prognostic factor for clinical outcome after unilateral adrenalectomy. METHODS: We retrospectively analyzed volumes of both adrenal glands of the 180 CT-scans (88/180 with unilateral and 92/180 with bilateral disease) of the patients with PA included in the SPARTACUS trial of which 85 also had undergone an AVS. In addition, we examined CT-scans of 20 healthy individuals to compare adrenal volumes with published normal values. RESULTS: Adrenal volume was higher for the left than the right adrenal (mean and SD: 6.49 ± 2.77 ml versus 5.25 ± 1.87 ml for the right adrenal; p < 0.001). Concordance between volumetry and AVS in subtyping was 58.8%, versus 51.8% between conventional CT results and AVS (p = NS). The volumes of the contralateral adrenals in the patients with unilateral disease (right 4.78 ± 1.37 ml; left 6.00 ± 2.73 ml) were higher than those of healthy controls reported in the literature (right 3.62 ± 1.23 ml p < 0.001; left 4.84 ± 1.67 ml p = 0.02). In a multivariable analysis the contralateral volume was not associated with biochemical or clinical success, nor with the defined daily doses of antihypertensive agents at 1 year follow-up. CONCLUSIONS: Volumetry of the adrenal glands is not superior to current assessment of adrenal size by CT for subtyping patients with PA. Furthermore, in patients with unilateral disease the size of the contralateral adrenal is enlarged but its size is not associated with outcome.

Utilização e percepção da tomografia computadorizada de feixe cônico por especialistas em cirurgia e traumatologia bucomaxilofacial para avaliação de terceiros molares inferiores impactados / Use and perception of cone beam computed tomography by oral & maxillofacial surgeons for impacted lower third molars evaluation

Objetivo: conhecer o perfil demográfico e as características que levam à solicitação de tomografia computa-dorizada de feixe cônico (TCFC) pelos especialistas em Cirurgia e Traumatologia Bucomaxilofacial (CTBMF) do estado do Rio Grande do Sul, para diagnóstico e planejamento cirúrgico de terceiros molares inferiores (3MI) impactados. Métodos: foram enviados questionários eletrônicos para todos os especialistas em CTBMF do RS. O questionário compreendia perguntas demográficas, clínicas e imaginológicas. O teste Qui-Quadra-do foi utilizado para verificar a associação entre as variáveis. Resultados: 115 questionários foram respondi-dos.O exame mais solicitado foi a panorâmica (95%). A TCFC foi solicitada por 50 especialistas (30 utilizam software). Localização do canal mandibular, dilaceração radicular e reabsorção do segundo molar são os aspectos mais avaliados na TCFC (P < 0,05); já o contato da raiz com o canal mandibular foi dito ser avaliado nos dois exames. Complicações permanentes foram relatadas por 21 especialistas, associadas a profissionais com maior tempo de graduação e/ou especialização (P < 0,05), mas não com o tipo de exame solicitado (P > 0,05). Na percepção dos especialistas, a TCFC tem papel importante em casos de alta complexidade. Con-clusão: a panorâmica ainda é o exame mais utilizado para avaliação de 3MI impactados pelos especialistas em CTBMF do RS, porém a TCFC tem sido solicitada para complementação do diagnóstico e planejamento e como meio de segurança jurídica do profissional.(AU)

Objective: to recognize the demographic profile and the characteristics that lead to the request of cone beam computed tomography (CBCT) by Oral & Maxillofacial (OMF) Surgeons in the state of RS for the diagnosis and surgical planning of impacted lower third molars (3LM). Methods: electronic questionnaires were sent to all OMF surgeons in RS. The questionnaire comprised demographic, clinical, and imaging questions. The chi-square test was used to verify the association between variables. Results: 115 questionnaires were answered. The most requested exam was the panoramic (95%). CBCT was requested by 50 specialists (30 use software). Localization of the mandibular canal, root dilaceration, and resorption of the second molar are the most evaluated aspects in the CBCT (P <0.05); the contact of the root with the mandibular canal was said to be evaluated in both exams. Permanent complications were reported by 21 OMF surgeons, and were related to the time of graduation and/or specialization (P < 0.05), but not to the type of exam (P > 0.05). In the OMF surgeons' perception, the CBCT has an important role in cases of high complexity. Conclusion: panoramic radiograph still is the most used exam for the assessment of impacted 3LM by OMF surgeons in RS, however, CBCT has been requested to complement the diagnosis and treatment plan, and as a means of professional legal security.(AU)

Anatomical variations of clivus: a descriptive anatomical study.

PURPOSE: The clivus is a part of the sphenoid bone. It may show some anatomical variations such as fossa navicularis magna (FNM), canalis basilaris medianus (CBM) and craniopharyngeal canal (CPC). These variations have been associated with conditions like meningitis and tumors of skull base. Inadequate information about these structures may pose a risk of inaccurate diagnosis resulting in unwarranted interventional procedures. Hence, the knowledge about the prevalence of these variations is important. Thus, the objective of this study was to determine the prevalence of fossa navicularis magna, craniopharyngeal canal and canalis basilaris medianus and its types utilizing cone-beam computed tomography (CBCT) images. METHODS: Retrospectively, a total of 350 CBCT scans were evaluated for the presence of FNM, CBM, its types and CPC. The analysis was done by two observers independently. Cohen's kappa statistics was used to determine the interobserver agreement. RESULTS: FNM was noted in 19.4% cases, CBM in 9.7% cases, whereas CPC was not identified in any case. Type 5 was the most common type of CBM. There was no significant difference (p > 0.05) between genders and age groups for the prevalence and a highly significant (p < 0.01) substantial agreement between observers for the prevalence of FNM and highly significant (p < 0.01) moderate agreement for the prevalence of CBM and its types was obtained. CONCLUSION: FNM, CBM, CPC, albeit rare anatomical variations of clivus, knowledge of these structures is important for radiologists, anatomists and surgeons to avoid misdiagnosis and provide awareness to the individual of a higher possibility of meningitis or tumors of the skull base.

Incidence of anomalous canals in the base of the skull: a retrospective radio-anatomical study using cone-beam computed tomography.

PURPOSE: Several skull-base foramina including foramen meningo-orbitale, craniopharyngeal canals, canaliculus innominatus, foramen vesalius, palatovaginal canals, and canalis basalis medianus are visible on cone-beam computed tomographs. A good understanding of the anatomical variants of these foramina is important to accurately diagnose fractures, understand the paths that infections may take, and identify associated anomalies. We used cone-beam computed tomography to measure the incidences of skull-base foramen variants in a normal population. METHODS: A total of 350 subjects (200 females, 150 males, 6-30 years of age) were included. The prevalences of foramen meningo-orbitale, craniopharyngeal canals, canaliculus innominatus, foramina vesalius, palatovaginal canals, and canalis basalis medianus were evaluated by age and gender. RESULTS: Subject age ranged from 6 to 30 years (mean age ± SD = 15.1 ± 4.08). Foramen meningo-orbitale, craniopharyngeal canals, canaliculus innominatus, foramen vesalius, palatovaginal canal, and canalis basalis medianus were observed in 51 (14.6%), 19 (5.4%), 60 (17.1%), 145 (41.1%), 34 (9.7%), and 15 (4.3%) patients, respectively. CONCLUSIONS: Skull-base foramina are important clinically and radiologically. Imaging of such variants via cone-beam computed tomography is valuable for both physicians and patients. Few studies of skull-base foramina have used cone-beam computed tomography. Additional research is required for a fuller understanding of this phenomenon.

Feasibility of Gold Fiducial Markers as a Surrogate for Gross Tumor Volume Position in Image-Guided Radiation Therapy of Rectal Cancer.

PURPOSE: To evaluate the feasibility of fiducial markers as a surrogate for gross tumor volume (GTV) position in image-guided radiation therapy of rectal cancer. METHODS AND MATERIALS: We analyzed 35 fiducials in 19 patients with rectal cancer who received short-course radiation therapy or long-course chemoradiation therapy. Magnetic resonance imaging examinations were performed before and after the first week of radiation therapy, and daily pre- and postirradiation cone beam computed tomography scans were acquired in the first week of radiation therapy. Between the 2 magnetic resonance imaging examinations, the fiducial displacement relative to the center of gravity of the GTV (COGGTV) and the COGGTV displacement relative to bony anatomy were determined. Using the cone beam computed tomography scans, inter- and intrafraction fiducial displacement relative to bony anatomy were determined. RESULTS: The systematic error of the fiducial displacement relative to the COGGTV was 2.8, 2.4, and 4.2 mm in the left-right, anterior-posterior (AP), and craniocaudal (CC) directions, respectively. Large interfraction systematic errors of up to 8.0 mm and random errors up to 4.7 mm were found for COGGTV and fiducial displacements relative to bony anatomy, mostly in the AP and CC directions. For tumors located in the mid and upper rectum, these errors were up to 9.4 mm (systematic) and 5.6 mm (random) compared with 4.9 mm and 2.9 mm for tumors in the lower rectum. Systematic and random errors of the intrafraction fiducial displacement relative to bony anatomy were ≤2.1 mm in all directions. CONCLUSIONS: Large interfraction errors of the COGGTV and the fiducials relative to bony anatomy were found. Therefore, despite the observed fiducial displacement relative to the COGGTV, the use of fiducials as a surrogate for GTV position reduces the required margins in the AP and CC directions for a GTV boost using image-guided radiation therapy of rectal cancer. This reduction in margin may be larger in patients with tumors located in the mid and upper rectum compared with the lower rectum.

Liver Graft Volume Estimation by Manual Volumetry and Software-Aided Interactive Volumetry: Which is Better?

PURPOSE: Estimation of graft volume is critical in living donor liver transplantation (LDLT). In this study, we aimed to evaluate the accuracy of software-aided automated computer tomography (CT) volumetry in the preoperative assessment of graft size for LDLT and to compare this method with manual volumetry. MATERIALS AND METHODS: Forty-one donors (27 men; 14 women) with a mean age in years ± standard deviation (28.4 ± 6.6) underwent contrast-enhanced CT prior to graft removal for LDLT. A liver transplant surgeon determined the weights of liver grafts using automated 3-dimensional volumetry software, and an abdominal radiologist specializing in liver imaging independently and blindly used the commercial interactive volumetry-assisted software on a viewing workstation to determine the liver volume on CT images. Both results were then compared to the weights of actual grafts obtained during surgery. Intraclass correlation coefficients were used to assess the consistency of numerical measurements and Pearson correlation coefficients were calculated to detect a linear relationship between numerical variables. To compare correlation coefficients, z scores were used. RESULTS: Regarding the right and left lobe graft volume estimation by the surgeon, there was a positive correlation between the results and actual graft weight (r = 0.834; P = .001; and r = 0.587; P = .001, respectively). Likewise, graft volume estimation by the radiologist for the right and left lobe was also positively correlated with the actual graft weight (r = 0.819; P = .001 and r = 0.626, P = .001, respectively). There was no significant difference between correlation coefficients (P = .836). CONCLUSION: Volumetric measurement of donor graft using 3-dimensional software provides comparable results to manual CT calculation of liver volume.

Radiation Exposure During Transarterial Chemoembolization: Angio-CT Versus Cone-Beam CT.

INTRODUCTION: Cone-beam computed tomography (CBCT) has been developed to improve reliability of many interventional radiology (IR) procedures performed with Angio system, such as transarterial chemoembolization (TACE). Angio-CT has emerged as a new imaging technology that combines a CT scanner with an Angio system in the same IR suite. The purpose of our study was to compare Angio system with CBCT capability and Angio-CT in terms of patient radiation exposure during TACE procedures. MATERIALS AND METHODS: Consecutive TACE procedures performed between January 2016 and September 2017 with the two imaging modalities (Artis Zeego defining the CBCT group and Infinix-i 4D-CT defining the Angio-CT group) were reviewed. TACE and patient's characteristics and patient radiation exposure parameters were collected. Dose-area products (DAP) and dose-length products (DLP) were converted into effective doses (ED) using conversion factors. Accuracy of tumor targeting and response was retrospectively assessed. RESULTS: A total of 114 TACE procedures in 96 patients were included with 57 procedures in each group. The total ED in the Angio-CT group was 2.5 times lower than that in the CBCT group (median 15.4 vs. 39.2 mSv, p < 0.001). Both 2D ED and 3D ED were lower in the Angio-CT group than in the CBCT group (5.1 vs. 20 mSv, p < 0.001, and 7.4 vs. 17.9 mSv, p < 0.001, respectively). There was no significant difference neither in terms of classes of tumor targeting (p = 0.509) nor in terms of classes of tumor response (p = 0.070) between both groups. CONCLUSION: Angio-CT provides significant decrease in patient effective dose during TACE procedures compared to Angio system with CBCT.

A systematic review on incidental findings in cone beam computed tomography (CBCT) scans.

OBJECTIVES: Cone beam CT's use (CBCT) in dentistry is increasing. Incidental findings (IFs: discoveries unrelated to the original purpose of the scan), are frequently found as a result of a large field of view. The aim of the systematic review is to analyze present literature on IFs using CBCT. METHODS AND MATERIALS: The authors searched online databases of studies and assessed the prevalence of IFs among patients undergoing head and neck CBCT scans. STROBE criteria was used to evaluate the quality of the studies. RESULTS: The original search retrieved 509 abstracts of which only 10 articles met the inclusion criteria. The sample size varied between 90 and 1000 participants. The frequency of IFs of the selected articles were 24.6-94.3%. The most common non-threatening IFs were found in the airway, such as mucous retention cyst (55.1%) and sinusitis (41.7%). Other non-threatening IFs were soft tissue calcifications such as calcified stylohyloid ligament (26.7%), calcified pineal gland (19.2%), and tonsillolith (14.3%). Threatening IFs were rare findings (1.4%). Three articles reported incidental carotid artery calcifications with a prevalence of 5.7-11.6%. Pathological findings were not common between the articles, but still relevant (2.6%). The studies had a risk of bias varying from moderate to low. CONCLUSIONS: There is a high frequency of IFs, yet not all of them require immediate medical attention. The low prevalence of threatening IFs emphasizes that CBCT should not be considered a substitution for conventional radiographs, but when used, the scans should be evaluated by a maxillofacial radiologist.

Referring Physicians Assess the Quality of Outpatient Diagnostic Imaging Services: Development and Psychometric Evaluation of a Questionnaire.

GOAL: In order to ensure high-quality cooperation between referring physicians and imaging services, it is important to assess the quality of imaging services as perceived by referring physicians. The present study aimed to develop and validate a questionnaire for referring physicians to assess the quality of outpatient diagnostic imaging services. MATERIALS & METHODS: The questionnaire was developed by discussing and modifying an existing instrument by the German Association of Surgeons. After qualitative pretesting, the instrument was tested with physicians referring to four outpatient diagnostic imaging services in Switzerland. The results were first assessed using descriptive statistics. The final instrument was tested for validity using the concept of known-groups validity. The hypothesis underlying this procedure was that physicians referring frequently to services estimated the quality of these services to be higher than physicians who referred less often to services. The differences in ratings were assessed using a one-sided two-sample Wilcoxon test. The final questionnaire was tested for internal consistency and reliability using Cronbach's Alpha. RESULTS: Results show a high level of satisfaction of referring physicians with the relevant services but also potential for quality improvement initiatives. The psychometric evaluation of the final questionnaire shows that it is a valid instrument, showing significant differences between the ratings of physicians referring with high and low frequency. Furthermore, the instrument proves to be consistent and reliable. CONCLUSION: The final instrument presents a valid, consistent and reliable option for assess the quality of outpatient diagnostic imaging services as perceived by referring physicians. Results can be used as a basis for quality improvement. KEY POINTS: · A newly developed questionnaire assesses the quality of outpatient diagnostic imaging services as perceived by referring physicians. The questionnaire was developed and tested in Switzerland.. · Psychometric evaluation showed the questionnaire to be a valid, consistent and reliable instrument.. · Results are of interest for imaging services as well as for initiatives encompassing several services.. CITATION FORMAT: · Jossen M, Valeri F, Heilmaier C et al. Referring Physicians Assess the Quality of Outpatient Diagnostic Imaging Services: Development and Psychometric Evaluation of a Questionnaire. Fortschr Röntgenstr 2019; 191: 725 - 731.

Medical Radiation Exposure in the United States: 2006-2016 Trends.

The use of radiation in medicine and the associated population dose grew very rapidly from 1980-2006 predominantly as a result of computed tomography and nuclear medicine. Over the last decade there have been significant changes in image detectors and processing with almost complete elimination of film use. Economic and reimbursement issues have also had a significant effect on usage. After about 2010, the volume of computed tomography and interventional techniques has been fairly level, plain radiography has declined slightly, and noninterventional fluoroscopy has declined dramatically. Nuclear medicine procedures have also declined significantly. Cone-beam computed tomography has expanded particularly in dental radiography. The use of several complex types of image-guided radiotherapy has increased significantly. National Council on Radiation Protection and Measurements' Scientific Committee 4-9 is currently conducting a full assessment for 2016 of collective and per caput effective dose. The report is expected to be completed in 2019, and preliminary work suggests a decrease in collective and per caput effective dose from that previously estimated for 2006.

Association between sella turcica bridging and palatal canine impaction: Evaluation using lateral cephalograms and CBCT.

INTRODUCTION: The purpose of this study was to find a correlation between sella turcica bridging and the presence of a palatal impacted canine, using lateral cephalograms and CBCT. MATERIAL AND METHOD: We selected the lateral cephalograms and CBCTs of 60 patients meeting specific criteria. The radiographs were analysed to study the relationship between sella turca bridging and several factors. The presence or absence of a partial or total bridging was deducted by measuring the dimensions of the sella turcica and by using an accurate scoring system. RESULTS AND CONCLUSION: Our study did not show any statistically significant association between sella turcica bridging as diagnosed on the lateral cephalogram and the CBCT images and the following factors: age, gender, facial type, skeletal class and the presence of an impacted canine. We found a significant difference for the classification of the sella turcica between these two radiographic methods.

Precision and reliability of Dolphin 3-dimensional voxel-based superimposition.

INTRODUCTION: Superimposition of 2 cone-beam computed tomography images is possible by using landmarks, surfaces, or density information (voxel-based). Voxel-based superimposition is automated and uses the most image content, providing accurate results. Until recently, this superimposition was extremely laborious, but a user-friendly voxel-based superimposition has recently been introduced. Our aim was to evaluate the precision and reliability of Dolphin 3-dimensional voxel-based superimposition (Dolphin Imaging, Chatsworth, Calif). METHODS: This was a retrospective study using existing scans of 31 surgical orthodontic patients with a mean age of 21 ± 8 years (range, 15-47 years). Each patient had a presurgical and a postsurgical scan taken within 12 months. Surgical patients were used since the reference area for superimposition was not affected by growth or surgical procedures. The volumes were superimposed using voxel-based methods from Dolphin Imaging and a tested method used previously. This method uses 2 open-source programs and takes about 3 hours to complete, whereas the Dolphin method takes under 5 minutes. The postsurgical scan was superimposed on the presurgical scan at the cranial base. Postsurgical registrations for both methods were compared with each other using the absolute closest point color map, with emphasis on 7 regions (nasion, A-point, B-point, bilateral zygomatic arches, and bilateral gonions). RESULTS: Intraclass correlations showed excellent reliability (0.96). The mean differences between the 2 methods were less than 0.21 mm (voxel size, 0.38). The smallst difference was in the left zygomatic area at 0.09 ± 0.07 mm, and the largest was in the right gonial region at 0.21 ± 0.13 mm. CONCLUSIONS: Dolphin 3-dimensional voxel-based superimposition, a fast and user-friendly method, is precise and reliable.

The Use of Cone-Beam Computed Tomography in Management of Patients Requiring Dental Implants: An American Academy of Periodontology Best Evidence Review.

BACKGROUND: Application of cone-beam computed tomography (CBCT) has grown exponentially across dentistry with a clear impact in implant dentistry. This review aims at providing the scientific context to understand if CBCT imaging should become the standard of care for patients requiring dental implants. METHODS: A literature search for CBCT applications in implant dentistry was performed using the PubMed database that included studies published between January 1, 2000, and June 24, 2017. RESULTS: Of 559 citations identified and manually screened, 161 were selected as suitable for the purpose of the review. The selected studies belonged to three distinct categories: 1) diagnosis and treatment outcome assessment, 2) implant treatment planning, and 3) anatomic characterization. CONCLUSIONS: The current available literature reflects an increased optimization of emerging CBCT imaging protocols and further highlights its diverse applications for dental implant therapy. This technology continues to be considered an advanced point-of-care imaging modality and should be used selectively as an adjunct to two-dimensional dental radiography. As with other ionizing radiation imaging modalities, CBCT imaging should be used only when the potential benefits to the patient outweigh the risks. Dental health care professionals should consider CBCT imaging only when they expect the diagnostic information yielded will lead to better patient care, enhanced patient safety, and ultimately facilitate a more predictable, optimal treatment outcome.

American Academy of Periodontology Best Evidence Consensus Statement on Selected Oral Applications for Cone-Beam Computed Tomography.

BACKGROUND: The American Academy of Periodontology (AAP) recently embarked on a Best Evidence Consensus (BEC) model of scientific inquiry to address questions of clinical importance in periodontology for which there is insufficient evidence to arrive at a definitive conclusion. This review addresses oral indications for use of cone-beam computed tomography (CBCT). METHODS: To develop the BEC, the AAP convened a panel of experts with knowledge of CBCT and substantial experience in applying CBCT to a broad range of clinical scenarios that involve critical structures in the oral cavity. The panel examined a clinical scenario or treatment decision that would likely benefit from additional evidence and interpretation of evidence, performed a systematic review on the individual, debated the merits of published data and experiential information, developed a consensus report, and provided a clinical bottom line based on the best evidence available. RESULTS: This BEC addressed the potential value and limitations of CBCT relative to specific applications in the management of patients requiring or being considered for the following clinical therapies: 1) placement of dental implants; 2) interdisciplinary dentofacial therapy involving orthodontic tooth movement in the management of malocclusion with associated risk on the supporting periodontal tissues (namely, dentoalveolar bone); and 3) management of periodontitis. CONCLUSION: For each specific question addressed, there is a critical mass of evidence, but insufficient evidence to support broad conclusions or definitive clinical practice guidelines.

Usos de tomografía computarizada de haz cónico en menores de 25 años en Talca, Chile / Use of cone-beam computed tomography in patients under 25 years of age from Talca, Chile

Introducción: la tomografía computarizada de haz cónico en odontología es de reciente introducción en Chile y no existe información acerca de su uso en poblaciones jóvenes. Desde el punto de vista de la protección radiológica, su uso es de especial preocupación en estos grupos, debido a su mayor susceptibilidad a las radiaciones ionizantes. Objetivos: determinar las indicaciones y parámetros de exposición de la tomografía computarizada de haz cónico en menores de 25 años atendidos en un periodo de 12 meses en un centro privado de radiología maxilofacial de Talca, Chile. Métodos: estudio observacional descriptivo de corte transversal. Se recolectaron datos de 240 exámenes. Se registraron los parámetros de exposición usados por un equipo SkyView (MyRay, Imola, Italia) y las indicaciones clínicas para cada examen. El procesamiento de los datos se realizó mediante estadística descriptiva, y se utilizó la prueba de Fisher. Resultados: la principal indicación fue localización de piezas dentarias (46 por ciento), seguido por planificación de exodoncia de terceros molares (25 por ciento), planificación de implantes (7,1 por ciento) y articulación temporomandibular (6 por ciento). En todos los grupos etarios el campo de visión pequeño fue el más usado (81 por ciento). El producto miliamperaje-tiempo fue 100,7 mAs en pre-escolares/niños, y 110,1-110,9 mAs en adolescentes y adultos jóvenes. La dosis efectiva fue 52,4 µSv en pre-escolares/niños y 62,1 µSv en adolescentes y adultos jóvenes. El 100 por ciento de los exámenes usó rotación parcial. El 96 porciento de las indicaciones concordó con lo señalado por las Guías Nº172 de la Comisión Europea. Conclusiones: las principales indicaciones en orden decreciente fueron localización de piezas dentarias, planificación de exodoncia de terceros molares, planificación de implantes y articulación temporomandibular. El campo de visión pequeño fue el más usado. La rotación total se encontró en todos los casos. No se encontró diferencias significativas en el uso del producto miliamperaje-tiempo y dosis efectiva entre los distintos grupos estudiados(AU)

Introduction: dental cone-beam computed tomography is a technology of recent introduction in Chile and there is no information regarding its use in young populations. From the point of view of radiation protection, its use with young patients is particularly worrisome, due to their greater susceptibility to ionizing radiation. Objective: determine the indications and exposure parameters of cone-beam computed tomography in patients under 25 years of age cared for in a 12-month period at a private maxillofacial radiology center in Talca, Chile. Methods: a observational descriptive cross-sectional study was conducted. Data were collected from 240 examinations. The exposure parameters used by a SkyView set (MyRay, Imola, Italy) were recorded, and note was taken of the clinical indications for each test. Data were processed by descriptive statistics using Fisher's test. Results: the main indication was tooth location (46 percent), followed by planning of third molar extraction (25 percent), implant planning (7.1 percent) and temporomandibular joint (6 percent). The small field of view was the most commonly used in all age groups (81 percent). The milliampere-time product was 100.7 mAs for preschool children and 110.1-110.9 mAs for adolescents and young adults. The effective dose was 52.4 µSv for preschool children and 62.1 µSv for adolescents and young adults. Partial rotation was used in 100 percent of the tests. 96 percent of the indications complied with Guideline No 172 of the European Commission. Conclusions: the main indications were tooth location, planning of third molar extraction, implant planning and temporomandibular joint, in that order. The small field of view was the most commonly used. Total rotation was found in all cases. Milliampere-time product and effective dose did not show any significant differences between the age groups studied(AU)

Pedicle screw insertion accuracy in terms of breach and reposition using a new intraoperative cone beam computed tomography imaging technique and evaluation of the factors associated with these parameters of accuracy: a series of 695 screws.

PURPOSE: The goals of this study were to assess the accuracy of pedicle screw insertion using an intraoperative cone beam computed tomography (CBCT) system, and to analyze the factors potentially influencing this accuracy. METHODS: Six hundred and ninety-five pedicle screws were inserted in 118 patients between October 2013 and March 2016. Screw insertion was performed using 2D-fluoroscopy or CBCT-based navigation. Accuracy was assessed in terms of breach and reposition. All the intraoperative CBCT scans, done after screw insertion, were reviewed to assess the accuracy of screw placement using two established classification systems: Gertzbein and Heary. Generalized linear mixed models were used to model the odds (95% CI) for a screw to lead to a breach according to the independent variables. RESULTS: The breach rate was 11.7% using the Gertzbein classification and 15.4% using the Heary classification. Seventeen screws (2.4%) were repositioned intraoperatively. The only factor affecting statistically the odds to have a breach was the indication of surgery. The patients with non-degenerative disease had a significantly higher risk of breach than those with degenerative disease. CONCLUSION: Use of intraoperative CBCT as 2D-fluoroscopy or coupled with a navigation system for pedicle screw insertion is accurate in terms of breach occurrence and reposition. However, these rates depend on the classification or grading system used. Use of a navigation system does not decrease the risk of breach significantly. And the risk of breach is higher in non-degenerative conditions (trauma, scoliosis, infection, and malignancy disease) than in degenerative diseases.

Accuracy of a new intraoperative cone beam CT imaging technique (Artis zeego II) compared to postoperative CT scan for assessment of pedicle screws placement and breaches detection.

PURPOSE: The goal of this study was to compare the accuracy of a novel intraoperative cone beam computed tomography (CBCT) imaging technique with that of conventional computed tomography (CT) scans for assessment of pedicle screw placement and breach detection. METHODS: Three hundred and forty-eight pedicle screws were inserted in 58 patients between October 2013 and March 2016. All patients had an intraoperative CBCT scan and a conventional CT scan to verify the placement of the screws. The CBCT and CT images were reviewed by two surgeons to assess the accuracy of screw placement and detect pedicle breaches using two established classification systems. Agreement on screw placement between intraoperative CBCT and postoperative CT was assessed using Kappa and Gwet's coefficients. Using CT scanning as the gold standard, the sensitivity, specificity, positive predictive value, and negative predictive value were calculated to determine the ability of CBCT imaging to accurately evaluate screw placement. RESULTS: The Kappa coefficient was 0.78 using the Gertzbein classification and 0.80 using the Heary classification, indicating a substantial agreement between the intraoperative CBCT and postoperative CT images. Gwet's coefficient was 0.94 for both classifications, indicating almost perfect agreement. The sensitivity, specificity, positive predictive value and negative predictive value of the CBCT images were 77, 98, 86, and 96%, respectively, for the Gertzbein classification and 79, 98, 88, and 96%, respectively, for the Heary classification. CONCLUSIONS: Intraoperative CBCT provides accurate assessment of pedicle screw placement and enables intraoperative repositioning of misplaced screws. This technique may make postoperative CT imaging unnecessary.

Image-guided radiotherapy for prostate cancer in the United Kingdom: a national survey.

OBJECTIVE: To survey the technology and practice of image-guided radiotherapy (IGRT) for prostate cancer in the UK. METHODS: A pre-tested semi-structured online questionnaire was sent to National Health Service (NHS) and private radiotherapy providers in the UK between March and April 2014. The survey was carried out on the Opinio© online platform. RESULTS: There was a high survey response rate of 83%. There is widespread use of intensity-modulated radiotherapy and advanced verification imaging modalities. Cone-beam CT (CBCT) is the main verification imaging modality in radical prostate radiotherapy, used in 66% of UK centres. Fiducial markers in combination with imaging were used in 30% of centres. Over half the centres used a daily imaging schedule, with a Day 1-3 frequency followed by weekly frequency used less commonly. 26% of centres used daily CBCT. CONCLUSION: There is widespread use of volumetric verification imaging with CBCT for prostate radiotherapy in the UK. There is no consensus on the optimal verification imaging schedule. Advances in knowledge: This survey provides an insight into contemporary UK practice of IGRT for prostate cancer, both in the NHS and private sector. It demonstrates the widespread use of CBCT imaging and highlights the need for further research to optimize the practice.

Evaluation of Osseointegration in Implants using Digital Orthopantomogram and Cone Beam Computed Tomography.

INTRODUCTION: Accurate assessment of osseointegration in dental implants requires precise radiographic visualization of pathologic conditions as well as anatomical structures. The present study aimed to evaluate the formation of bony tissue (osseointegration) using digital orthopantomogram (OPG) and cone beam computed tomography (CBCT) immediately after implant insertion (within 7 days) and 3 months postinsertion. MATERIALS AND METHODS: Twenty single-implant sites on mandi-bular posterior regions were selected on patients irrespective of their gender. Both digital OPG and CBCT were done within a week and again after 3 months of implant insertion surgery, using the same exposure parameters. RESULTS: Three of the 20 implants were submerged and were excluded as the crestal bone height could not be measured. The participants were recalled for radiographic measurements after 3 months of implant placement. On an average, there was 0.03 mm of osseointegration at the apical portion after 3 months of implant insertion on digital OPG; 0.04 mm of osseointegration at the crestal bone height after 3 months on digital OPG; and 0.01 mm of osseointegration at the apical portion after 3 months on CBCT. No change or ≤0.02 mm of osseointegration at crestal bone height after 3 months on CBCT. CONCLUSION: Both digital OPG and CBCT are significant for the assessment of osseointegration in implants, and hence, endow definite benefit for accurate assessment in terms of the success of the implant placement. CLINICAL SIGNIFICANCE: However, CBCT is a better mode of evaluating dental implants but one should keep in mind that radiographic examination must be conducted to the benefit of the patient by application of the lowest achievable dose.