Dentin Thickness of Pulp Chamber Floor in Primary Molars: Evaluation by Cone-Beam Computed Tomography

ABSTRACT Objective: Use cone-beam computed tomography (CBCT) images to evaluate the dentin thickness of the pulp chamber floor in primary molars. Material and Methods: Cross-sectional study, conducted with CBCT images of teeth of children. Primary molars with preserved pulp chamber floor were included. The dentin thickness of the pulp chamber floor in the primary molars was measured linearly in CBCT cross-sections. Data were descriptively analyzed and the Mann-Whitney test was applied (p<0.05). Results: 27 CBCT exams and 123 primary molars of children aged 4 to 13 years were analyzed; the majority was female (52.0%). In maxillary molars, the median dentin thickness was 1.50 (0.6-2.2) mm in the first and 1.65 (0.6-2.3) mm in the second (p=0.049) molars. In mandibular molars, the median was 1.20 (0.3-1.7) mm in the first and 1.60 (1.0-2.2) mm in the second (p<0.001) molars. Children aged 4 to 8 years showed less dentin thickness (p<0.001). Conclusion: The median dentin thickness of the pulp chamber floor in primary molars was 1.50 mm, ranging from 0.3 to 2.3 mm. Less dentin thickness was associated with younger children, teeth in the mandibular arch, and first molars.

Colonoscopía virtual de screening de cáncer colorrectal en pacientes con enfermedad diverticular / Virtual colonoscopy for colorectal cancer screening in patients with diverticular disease

CONTEXTO: El cáncer colorrectal (CCR) es un problema de salud pública en todo el mundo y particularmente em nuestro país, dada su elevada incidencia. En Argentina, según las estimaciones de incidencia del Observatorio Global de Cáncer de la OMS se estimaron 15.692 casos nuevos para el año 2018 en ambos sexos, concentrando el 13% del total de tumores, siendo el segundo cáncer más frecuente, por detrás del cáncer de mama en mujeres y el cáncer de próstata en hombres. En Argentina el CCR es el segundo cáncer de mayor mortalidad (luego del cáncer de pulmón), con más de 7.000 fallecimientos anuales. TECNOLOGÍA: La colonoscopía tomográfica computarizada, también conocida como colonoscopía virtual, fue desarrollada como un método mínimamente invasivo para examinar el colon.5 Se ha sugerido el uso de esta prueba para la detección de anomalías en el colon y el recto como por ejemplo, CCR y pólipos. Esta tecnología implica el uso de tomografía computarizada helicoidal (TC) e imágenes generadas por computadora para producir imágenes bidimensionales y tridimensionales (3D) de alta resolución del colon y el recto. OBJETIVO: El objetivo del presente informe es evaluar la evidencia disponible acerca del desempeño diagnóstico, la eficacia, seguridad y aspectos relacionados a las políticas de cobertura del uso de colonoscopia virtual para screening de CCR en pacientes con enfermedad diverticular. MÉTODOS: Se realizó una búsqueda en las principales bases de datos bibliográficas, en buscadores genéricos de internet, y financiadores de salud. Se priorizó la inclusión de revisiones sistemáticas (RS), ensayos clínicos controlados aleatorizados (ECAs), evaluaciones de tecnologías sanitarias (ETS), evaluaciones económicas, guías de práctica clínica (GPC) y políticas de cobertura de diferentes sistemas de salud. RESULTADOS: Se incluyeron cuatro RS, un ECA, seis GPC, dos informes de ETS, una RS de evaluaciones económicas, y 12 informes de políticas de cobertura de CTC en screening de CCR en pacientes con enfermedad diverticular. CONCLUSIONES: No se encontraron estudios que comparen de forma directa la utilización de colonoscopía virtual por tomografía computarizada contra otros métodos diagnósticos (excluyendo enema de bario de doble contraste) para el screening de cáncer colorrectal en pacientes con enfermedad diverticular. La decisión del método a utilizar podría basarse en consideraciones clínicas y preferencia de los pacientes y cuestiones como la accesibilidad a las diferentes modalidades de cribado. Se encontró evidencia de moderada calidad que sugiere que la colonoscopía virtual tiene uma sensibilidad superior al enema de bario de doble contraste en el screening de cáncer colorrectal em la población general y podría inferirse que también la tendría en pacientes con enfermedad diverticular. Financiadores públicos y privados de países de altos ingresos cubren el uso de colonoscopía virtual en el screening de cáncer colorrectal en pacientes con antecedentes de videocolonoscopía incompleta o en los que la videocolonoscopía se encuentra contraindicada. Esta tecnología no es mencionada en el Programa Médico Obligatorio ni es reintegrada por el Sistema Único de Reintegro de la Argentina. Esta tecnología se encuentra recomendada por guías de práctica clínica como técnica de screening de cáncer colorrectal y en Argentina el Instituto Nacional del Cáncer la recomienda como uma alternativa válida para el tamizaje luego de una videocolonoscopía incompleta.

Assessment of Endoscopic Healing by Using Advanced Technologies Reflects Histological Healing in Ulcerative Colitis.

BACKGROUND: Several studies have reported that ulcerative colitis [UC] patients with endoscopic mucosal healing may still have histological inflammation. We investigated the relationship between mucosal healing defined by modified PICaSSO [Paddington International Virtual ChromoendoScopy ScOre], Mayo Endoscopic Score [MES] and probe-based confocal laser endomicroscopy [pCLE] with histological indices in UC. METHODS: A prospective study enrolling 82 UC patients [male 66%] was conducted. High-definition colonoscopy was performed to evaluate the activity of the disease with MES assessed with High-Definition MES [HD-MES] and modified PICaSSO and targeted biopsies were taken; pCLE was then performed. Receiver operating characteristic [ROC] curves were plotted to determine the best thresholds for modified PICaSSO and pCLE scores that predicted histological healing according to the Robarts Histopathology Index [RHI] and ECAP 'Extension, Chronicity, Activity, Plus' histology score. RESULTS: A modified PICaSSO of ≤ 4 predicted histological healing at RHI ≤ 3, with sensitivity, specificity, accuracy and area under the ROC curve [AUROC] of 89.8%, 95.7%, 91.5% and 95.9% respectively. The sensitivity, specificity, accuracy and AUROC of HD-MES to predict histological healing by RHI were 81.4%, 95.7%, 85.4% and 92.1%, respectively. A pCLE ≤ 10 predicted histological healing with sensitivity of 94.9%, specificity of 91.3%, accuracy of 93.9% and AUROC of 96.5%. An ECAP of ≤ 10 was predicted by modified PICaSSO ≤ 4 with accuracy of 91.5% and AUROC of 95.9%. CONCLUSION: Histological healing by RHI and ECAP is accurately predicted by HD-MES and modified virtual electronic chromoendoscopy PICaSSO, endoscopic score; and the use of pCLE did not improve the accuracy any further.

Immersive Virtual Colonoscopy.

Virtual colonoscopy (VC) is a non-invasive screening tool for colorectal polyps which employs volume visualization of a colon model reconstructed from a CT scan of the patient's abdomen. We present an immersive analytics system for VC which enhances and improves the traditional desktop VC through the use of VR technologies. Our system, using a head-mounted display (HMD), includes all of the standard VC features, such as the volume rendered endoluminal fly-through, measurement tool, bookmark modes, electronic biopsy, and slice views. The use of VR immersion, stereo, and wider field of view and field of regard has a positive effect on polyp search and analysis tasks in our immersive VC system, a volumetric-based immersive analytics application. Navigation includes enhanced automatic speed and direction controls, based on the user's head orientation, in conjunction with physical navigation for exploration of local proximity. In order to accommodate the resolution and frame rate requirements for HMDs, new rendering techniques have been developed, including mesh-assisted volume raycasting and a novel lighting paradigm. Feedback and further suggestions from expert radiologists show the promise of our system for immersive analysis for VC and encourage new avenues for exploring the use of VR in visualization systems for medical diagnosis.

Virtual Computed Tomography Colonography: Evaluation of 2D and Virtual 3D Image Quality of Sub-mSv Examinations Enabled by Third-generation Dual Source Scanner Featuring Tin Filtering.

RATIONALE AND OBJECTIVES: To evaluate two- and three-dimensional (2D and 3D) image quality of sub-milliSievert (mSv) computed tomography (CT) colonography utilizing a third-generation dual source CT scanner featuring a tin filter. METHODS: We retrospectively evaluated 26 consecutive patients who underwent third-generation dual source CT colonography, nine with the standard-dose clinical-scan protocol (SDP) and 17 with a low-dose protocol (LDP) featuring a tin filter. Radiation dose was evaluated by volume computed tomography dose index (CTDIvol), dose length product (DLP), effective dose (E), and size-specific dose estimate. Objective image quality was evaluated utilizing signal-to-noise ratio (SNR) derived from standardized placed regions of interest on the transverse 2D images and the ratio of SNR/CTDIvol (normalized SNR). Two radiologists in consensus assessed subjective image quality of the virtual 3D images. RESULTS: There were no significant differences in subjective image quality (P = .661). All examinations were rated "excellent" or "good" for diagnostic confidence. The mean total for DLP/E was 143.4 ± 29.8 mGy/3.00 ± 0.40 mSv in the SDP and therefore significantly higher than in the LDP with 36.9 ± 8.7 mGy/0.75 ± 0.16 mSv (P < .001). The SNR was 8.9 ± 2.1 in the SDP and 4.9 ± 0.8 in the LDP. CONCLUSIONS: Third-generation dual source CT featuring a tin filter enables consistent sub-mSv colonography without substantially impairing image quality.

Update on PET/CT colonography in the diagnosis of colorectal cancer / Actualización sobre la utilidad de la PET/TC colonografía en el diagnóstico del cáncer colorrectal

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Successful balloon overtube-guided colorectal endoscopic submucosal dissection by a gastroscope

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Reducing the Radiation Dose for CT Colonography: Effect of Low Tube Voltage and Iterative Reconstruction.

RATIONALE AND OBJECTIVES: The purpose of this study was to assess the effect of a low-tube-voltage technique and iterative reconstruction (IR) on the radiation dose and image quality of computed tomography colonography (CTC). MATERIALS AND METHODS: We studied 30 patients (14 women and 16 men; mean age, 64.5 ± 13.1 years; range, 39-90 years) with colorectal cancer referred for surgical treatment. All underwent CTC with fecal tagging under a standard 120-kVp protocol in the supine position and a 100-kVp protocol in the prone position. The 120-kVp images were reconstructed with filtered back projection (FBP). The 100-kVp images were postprocessed using FBP and a hybrid type of IR (adaptive iterative dose reduction 3D). The effective radiation dose (ED), image noise, and contrast-to-noise ratio (CNR) were compared among the three protocols. The visual image quality was scored on a four-point scale. RESULTS: The mean ED was significantly lower under the 100-kVp protocol than the 120-kVp protocol, resulting in a 27% radiation dose decrease (3.5 ± 2.0 vs 2.5 ± 1.5 mSv; P < .01). Image noise decreased by 48%, and the mean attenuation of tagged fluid increased from 452 to 558 HU on images acquired at 100 kVp with IR compared to that in the 120-kVp protocol; these differences were significant. The mean CNR was significantly higher under the 100 kVp with IR than the other two protocols. We found no significant differences in the visual scores for diagnostic utility between the 100 kVp with IR and the 120 kVp with FBP protocol (P = .10). CONCLUSIONS: Low-tube-voltage CTC reduced the radiation dose by approximately 27% while maintaining the image quality.

Perforación vaginal iatrogénica tras colonoscopia virtual / Latrogenic vaginal perforation after computed tomographic colonography

La colonoscopia virtual o colonografía por tomografía computarizada (TC) es una alternativa potencial a la colonoscopia convencional para la detección de pólipos y cáncer colorrectal. Presentamos un caso inusual de perforación iatrogénica vaginal durante una colonoscopia virtual. El paciente fue tratado con medidas conservadoras sin complicaciones. El presente caso es el primero en la literatura de perforación vaginal iatrogénica debido a la introducción del catéter de Foley a través de la vagina durante la realización de una colonografía por TC. La perforación vaginal es una complicación rara, fácilmente evitable con una correcta exploración clínica

Computed tomographic colonography is a potential alternative to conventional colonoscopy for the detection of colorectal polyps and cancers. We present an unusual case of iatrogenic vaginal perforation during a computed tomographic colonography. The patient was managed with conservative treatment without complications. The present case is the first in the literature of iatrogenic vaginal perforation due to the introduction of the Foley's catheter through vagina during the accomplishment of a computed tomographic colonography. Vaginal perforation is a rare complication, easily avoidable with a correct clinical exploration

History, evolution, and current status of radiologic imaging tests for colorectal cancer screening.

Colorectal cancer screening is thought to be an effective tool with which to reduce the mortality from colorectal cancer through early detection and removal of colonic adenomas and early colon cancers. In this article, we review the history, evolution, and current status of imaging tests of the colon-including single-contrast barium enema, double-contrast barium enema, computed tomographic (CT) colonography, and magnetic resonance (MR) colonography-for colorectal cancer screening. Despite its documented value in the detection of colonic polyps, the double-contrast barium enema has largely disappeared as a screening test because it is widely perceived as a labor-intensive, time-consuming, and technically demanding procedure. In the past decade, the barium enema has been supplanted by CT colonography as the major imaging test in colorectal cancer screening in the United States, with MR colonography emerging as another viable option in Europe. Although MR colonography does not require ionizing radiation, the radiation dose for CT colonography has decreased substantially, and regular screening with this technique has a high benefit-to-risk ratio. In recent years, CT colonography has been validated as an effective tool for use in colorectal cancer screening that is increasingly being disseminated.

Reducing image noise in computed tomography (CT) colonography: effect of an integrated circuit CT detector.

OBJECTIVE: To investigate whether the integrated circuit (IC) detector results in reduced noise in computed tomography (CT) colonography (CTC). METHODS: Three hundred sixty-six consecutive patients underwent clinically indicated CTC using the same CT scanner system, except for a difference in CT detectors (IC or conventional). Image noise, patient size, and scanner radiation output (volume CT dose index) were quantitatively compared between patient cohorts using each detector system, with separate comparisons for the abdomen and pelvis. RESULTS: For the abdomen and pelvis, despite significantly larger patient sizes in the IC detector cohort (both P < 0.001), image noise was significantly lower (both P < 0.001), whereas volume CT dose index was unchanged (both P > 0.18). Based on the observed image noise reduction, radiation dose could alternatively be reduced by approximately 20% to result in similar levels of image noise. CONCLUSION: Computed tomography colonography images acquired using the IC detector had significantly lower noise than images acquired using the conventional detector. This noise reduction can permit further radiation dose reduction in CTC.

3D Reconstruction of virtual colon structures from colonoscopy images.

This paper presents the first fully automated reconstruction technique of 3D virtual colon segments from individual colonoscopy images. It is the basis of new software applications that may offer great benefits for improving quality of care for colonoscopy patients. For example, a 3D map of the areas inspected and uninspected during colonoscopy can be shown on request of the endoscopist during the procedure. The endoscopist may revisit the suggested uninspected areas to reduce the chance of missing polyps that reside in these areas. The percentage of the colon surface seen by the endoscopist can be used as a coarse objective indicator of the quality of the procedure. The derived virtual colon models can be stored for post-procedure training of new endoscopists to teach navigation techniques that result in a higher level of procedure quality. Our technique does not require a prior CT scan of the colon or any global positioning device. Our experiments on endoscopy images of an Olympus synthetic colon model reveal encouraging results with small average reconstruction errors (4.1 mm for the fold depths and 12.1 mm for the fold circumferences).

Plataforma colaborativa multimídia para apoio ao diagnóstico de lesões bucais em ambientes de teleodontologia / Collaborative multimedia platform to support oral diagnosis in teledentistry environments

Este artigo tem por objetivo apresentar uma solução tecnológica desenvolvida para permitir atividades colaborativas de diagnóstico de lesões bucais em ambientes de Teleodontologia. Trata-se de uma plataforma totalmente baseada na web e que permite o gerenciamento e compartilhamento de imagens clínicas, radiográficas e histopatológicas, dispensando a instalação de qualquer programa adicional no computador do usuário. Como suporte à colaboração através do navegador, as ações efetuadas por um usuário são replicadas e visíveis ao outro usuário conectado, sendo possível a discussão e troca de informações sobre o caso através de chat e/ou áudiovideoconferência. Ferramentas de Telessaúde podem ofereçe diferentes oportunidades para assistência e educação em Odontologia. Ao permitir a visualização de diferentes aspectos da doença do paciente, a solução aqui apresentada tem potencial para viabilizar: (1) a troca de informações entre profissionais de saúde atuantes em distintos níveis de assistência e (2) a tutoria, à distância, nos diferentes níveis de formação (graduação, pós-graduação e educação continuada) (AU).

This paper presents a technological solution developed to enabling collaborative activities in Teledentistry environments. This is a platform composed by a set of tools for the management and sharing of clinical, radio graphic and histopathologic images. The proposed solution is fully web-based, requiring only a web browser installed; it's not necessary to install any other software on the user's computer. As collaboration support, the actions performed by a user with mouse and keyboard are replicated and visible to the other connected user. This toolkit allows the discussion of disease via chat and/or videoconferen ing. Telehealth's tools offer opportunities for assistance and education in Dentistry. By allowing realtime viewing and discussion of different aspects of a disease this technological solution has potential to facilitate: (1) exchange of information between health professionals at different levels of assistance and (2) distance tutoring at different levels of training (undergraduate, postgraduate and continuing education) (AU).

Predicting polyp location on optical colonoscopy from CT colonography by minimal-energy curve modeling of the colonoscope path.

The ability to accurately locate a polyp found on computed tomographic colonography (CTC) at subsequent optical colonoscopy (OC) is an important task in colorectal cancer screening. We present a method to more accurately match polyp locations at CTC and OC. A colonoscope was modeled as a flexible tube with negligible stretch and minimal strain. The path of the colonoscope was estimated using a minimal-energy curve method. The energy function was defined and optimized by a subdivision scheme. The prediction of polyp locations at OC from CTC was converted to an optimization problem. The prediction performance was evaluated on 134 polyps by comparing the predicted with the true polyp locations at OC. The method can accurately predict polyp locations at OC to within ±0.5 colonoscope mark (5 cm) for more than 58% of polyps and to within ±1 colonoscope mark (10 cm) for more than 96% of polyps, significantly improving upon previously published methods. This method can be easily incorporated into routine OC practice and allow the colonoscopist to begin the examination by targeting locations of potential polyps found at CTC.

Flexible sigmoidoscopy does not significantly increase polyp and cancer detection yield when used to supplement CT colonography.

BACKGROUND AND AIMS: Flexible sigmoidoscopy (FS) increases polyp and carcinoma detection in addition to double contrast barium enema (DCBE). However, CT colonography (CTC) is now the preferred technique. Our aim was to explore whether FS increases polyp and carcinoma detection rates when used in addition to CTC. METHODS: Patients who underwent FS and CTC between 2007 and 2009 were included and data were collected from patient records. Yields of polyp, adenoma and carcinoma detection were calculated for FS and CTC. RESULTS: In a cohort of 294 patients, CTC detected 36 patients with carcinomas while FS detected 28. One rectal cancer not seen on CTC was diagnosed by FS. Polyps were seen by CTC in 66 and FS in 45 patients. In 5 patients FS found polyps that were not detected by CTC; 3 of which were small adenomas. FS detected extra adenomas or carcinomas in 1.36% (4/294). Adding FS to CTC neither increased the cancer nor the polyp detection yield significantly. CONCLUSIONS: This first study investigating the use of FS in addition to CTC detected little additional pathology. The routine use of FS as a supplement to CTC for adenoma and carcinoma detection is of questionable utility.

Colonoscopia hoy: ¿real o virtual? / Colonoscopy today: real or virtual?

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[A virtual visualization system for colon polyp inspection].

The virtual colonoscopy, virtual flattening and virtual splitting method are enhanced by the GPGPU model. The novel virtual eversion method is integrated for fast polyp detection. The experimental result showed that the system and various visualization methods can represent the colon inner-surface clearly and exactly, supporting real-time man-machine interaction. The proposed system is promising in human gastrointestinal cancer and polyp inspection.