Gender assessment through three-dimensional analysis of maxillary sinuses by means of Cone Beam Computed Tomography

OBJECTIVE: The availability of a low dose radiation technology such as Cone Beam Computed Tomography (CBCT) in dental practice has increased the number of scans available for forensic purposes. Moreover, specific software allows for three-dimensional (3D) characterization of the maxillary sinuses. This study was performed to determine whether sinus maxillary volumes can be useful to identify gender after validating the use of the Dolphin software as a tool for volumetric estimation of maxillary sinus volumes. PATIENTS AND METHODS: The validation was performed by four different operators measuring the volume of six phantoms, where the real volume was already known. The maxillary sinus volumes of 52 patients (26 males and 26 females) mean age 24.3 were calculated and compared between genders and sagittal skeletal class subdivision. The measurements for patients and phantoms were based on CBCT scans (ILUMA™) processed by Dolphin 3D software. RESULTS: No statistical difference was observed between the real volume and the volume measurements performed by the operators. No statistical difference was found in patient's maxillary sinus volumes between gender. CONCLUSIONS: Based on our results, it is not possible to support the use of maxillary sinuses to discern sexual difference in corpse identification

Evaluation and reproducibility of volumetric measurements on maxillary sinuses.

The aim of our study is to validate the use of Dolphin Imaging software to analyze CBCT images as a tool for volumetric estimation of maxillary sinus volumes and to test the intra- and inter-examiner reproducibility of this technique. In addition, other aims is to demonstrate the absence of correlation between the volumetric dimensions of the paranasal maxillary spaces and the three different skeletal types

SURGICAL NAVIGATION AND AUGMENTED REALITY FOR MARGINS CONTROL IN HEAD AND NECK CANCER

I tumori maligni del distretto testa-collo rappresentano un insieme di lesioni dalle diverse caratteristiche patologiche, epidemiologiche e prognostiche. Per una porzione considerevole di tali patologie, l’intervento chirurgico finalizzato all’asportazione completa del tumore rappresenta l’elemento chiave del trattamento, quand’anche esso includa altre modalità quali la radioterapia e la terapia sistemica. La qualità dell’atto chirurgico ablativo è pertanto essenziale al fine di garantire le massime chance di cura al paziente. Nell’ambito della chirurgia oncologica, la qualità delle ablazioni viene misurata attraverso l’analisi dello stato dei margini di resezione. Oltre a rappresentare un surrogato della qualità della resezione chirurgica, lo stato dei margini di resezione ha notevoli implicazioni da un punto di vista clinico e prognostico. Infatti, il coinvolgimento dei margini di resezione da parte della neoplasia rappresenta invariabilmente un fattore prognostico sfavorevole, oltre che implicare la necessità di intensificare i trattamenti postchirurgici (e.g., ponendo indicazione alla chemioradioterapia adiuvante), comportando una maggiore tossicità per il paziente. La proporzione di resezioni con margini positivi (i.e., coinvolti dalla neoplasia) nel distretto testa-collo è tra le più elevate in ambito di chirurgia oncologica. In tale contesto si pone l’obiettivo del dottorato di cui questa tesi riporta i risultati. Le due tecnologie di cui si è analizzata l’utilità in termini di ottimizzazione dello stato dei margini di resezione sono la navigazione chirurgica con rendering tridimensionale e la realtà aumentata basata sulla videoproiezione di immagini. Le sperimentazioni sono state svolte parzialmente presso l’Università degli Studi di Brescia, parzialmente presso l’Azienda Ospedale Università di Padova e parzialmente presso l’University Health Network (Toronto, Ontario, Canada). I risultati delle sperimentazioni incluse in questo elaborato dimostrano che l'impiego della navigazione chirurgica con rendering tridimensionale nel contesto di procedure oncologiche ablative cervico-cefaliche risulta associata ad un vantaggio significativo in termini di riduzione della frequenza di margini positivi. Al contrario, le tecniche di realtà aumentata basata sulla videoproiezione, nell'ambito della sperimentazione preclinica effettuata, non sono risultate associate a vantaggi sufficienti per poter considerare tale tecnologia per la traslazione clinica.Head and neck malignancies are an heterogeneous group of tumors. Surgery represents the mainstay of treatment for the large majority of head and neck cancers, with ablation being aimed at removing completely the tumor. Radiotherapy and systemic therapy have also a substantial role in the multidisciplinary management of head and neck cancers. The quality of surgical ablation is intimately related to margin status evaluated at a microscopic level. Indeed, margin involvement has a remarkably negative effect on prognosis of patients and mandates the escalation of postoperative treatment by adding concomitant chemotherapy to radiotherapy and accordingly increasing the toxicity of overall treatment. The rate of margin involvement in the head and neck is among the highest in the entire field of surgical oncology. In this context, the present PhD project was aimed at testing the utility of 2 technologies, namely surgical navigation with 3-dimensional rendering and pico projector-based augmented reality, in decreasing the rate of involved margins during oncologic surgical ablations in the craniofacial area. Experiments were performed in the University of Brescia, University of Padua, and University Health Network (Toronto, Ontario, Canada). The research activities completed in the context of this PhD course demonstrated that surgical navigation with 3-dimensional rendering confers a higher quality to oncologic ablations in the head and neck, irrespective of the open or endoscopic surgical technique. The benefits deriving from this implementation come with no relevant drawbacks from a logistical and practical standpoint, nor were major adverse events observed. Thus, implementation of this technology into the standard care is the logical proposed step forward. However, the genuine presence of a prognostic advantage needs longer and larger study to be formally addressed. On the other hand, pico projector-based augmented reality showed no sufficient advantages to encourage translation into the clinical setting. Although observing a clear practical advantage deriving from the projection of osteotomy lines onto the surgical field, no substantial benefits were measured when comparing this technology with surgical navigation with 3-dimensional rendering. Yet recognizing a potential value of this technology from an educational standpoint, the performance displayed in the preclinical setting in terms of surgical margins optimization is not in favor of a clinical translation with this specific aim

Deep learning-based fully automatic segmentation of the maxillary sinus on cone-beam computed tomographic images

The detection of maxillary sinus wall is important in dental fields such as implant surgery, tooth extraction, and odontogenic disease diagnosis. The accurate segmentation of the maxillary sinus is required as a cornerstone for diagnosis and treatment planning. This study proposes a deep learning-based method for fully automatic segmentation of the maxillary sinus, including clear or hazy states, on cone-beam computed tomographic (CBCT) images. A model for segmentation of the maxillary sinuses was developed using U-Net, a convolutional neural network, and a total of 19,350 CBCT images were used from 90 maxillary sinuses (34 clear sinuses, 56 hazy sinuses). Post-processing to eliminate prediction errors of the U-Net segmentation results increased the accuracy. The average prediction results of U-Net were a dice similarity coefficient (DSC) of 0.9090 ± 0.1921 and a Hausdorff distance (HD) of 2.7013 ± 4.6154. After post-processing, the average results improved to a DSC of 0.9099 ± 0.1914 and an HD of 2.1470 ± 2.2790. The proposed deep learning model with post-processing showed good performance for clear and hazy maxillary sinus segmentation. This model has the potential to help dental clinicians with maxillary sinus segmentation, yielding equivalent accuracy in a variety of cases.ope

One Step before 3D Printing\u2014Evaluation of Imaging Software Accuracy for 3-Dimensional Analysis of the Mandible: A Comparative Study Using a Surface-to-Surface Matching Technique

Abstract: The accuracy of 3D reconstructions of the craniomaxillofacial region using cone beam computed tomography (CBCT) is important for the morphological evaluation of specific anatomical structures. Moreover, an accurate segmentation process is fundamental for the physical reconstruction of the anatomy (3D printing) when a preliminary simulation of the therapy is required. In this regard, the objective of this study is to evaluate the accuracy of four dierent types of software for the semiautomatic segmentation of the mandibular jaw compared to manual segmentation, used as a gold standard. Twenty cone beam computed tomography (CBCT) with a manual approach (Mimics) and a semi-automatic approach (Invesalius, ITK-Snap, Dolphin 3D, Slicer 3D) were selected for the segmentation of the mandible in the present study. The accuracy of semi-automatic segmentation was evaluated: (1) by comparing the mandibular volumes obtained with semi-automatic 3D rendering and manual segmentation and (2) by deviation analysis between the two mandibular models. An analysis of variance (ANOVA) was used to evaluate dierences in mandibular volumetric recordings and for a deviation analysis among the dierent software types used. Linear regression was also performed between manual and semi-automatic methods. No significant dierences were found in the total volumes among the obtained 3D mandibular models (Mimics = 40.85 cm3, ITK-Snap = 40.81 cm3, Invesalius = 40.04 cm3, Dolphin 3D = 42.03 cm3, Slicer 3D = 40.58 cm3). High correlations were found between the semi-automatic segmentation and manual segmentation approach, with R coecients ranging from 0,960 to 0,992. According to the deviation analysis, the mandibular models obtained with ITK-Snap showed the highest matching percentage (Tolerance A = 88.44%, Tolerance B = 97.30%), while those obtained with Dolphin 3D showed the lowest matching percentage (Tolerance A = 60.01%, Tolerance B = 87.76%) (p < 0.05). Colour-coded maps showed that the area of greatest mismatch between semi-automatic and manual segmentation was the condylar region and the region proximate to the dental roots. Despite the fact that the semi-automatic segmentation of the mandible showed, in general, high reliability and high correlation with the manual segmentation, caution should be taken when evaluating the morphological and dimensional characteristics of the condyles either on CBCT-derived digital models or physical models (3D printing)

Comparative linear accuracy and reliability of cone beam CT derived 2-dimensional and 3-dimensional images constructed using an orthodontic volumetric rendering program.

The purpose of this project was to compare the accuracy and reliability of linear measurements made on 2D projections and 3D reconstructions using Dolphin 3D software (Chatsworth, CA) as compared to direct measurements made on human skulls. The linear dimensions between 6 bilateral and 8 mid-sagittal anatomical landmarks on 23 dentate dry human skulls were measured three times by multiple observers using a digital caliper to provide twenty orthodontic linear measurements. The skulls were stabilized and imaged via PSP digital cephalometry as well as CBCT. The PSP cephalograms were imported into Dolphin (Chatsworth, CA, USA) and the 3D volumetric data set was imported into Dolphin 3D (Version 2.3, Chatsworth, CA, USA). Using Dolphin 3D, planar cephalograms as well as 3D volumetric surface reconstructions were (3D CBCT) generated. The linear measurements between landmarks of each three modalities were then computed by a single observer three times. For 2D measurements, a one way ANOVA for each measurement dimension was calculated as well as a post hoc Scheffe multiple comparison test with the anatomic distance as the control group. 3D measurements were compared to anatomic truth using Student\u27s t test (PiÜ50.05). The intraclass correlation coefficient (ICC) and absolute linear and percentage error were determined as indices of intraobserver reliability. Our results show that for 2D mid sagittal measurements that Simulated LC images are accurate and similar to those from PSP images (except for Ba-Na), and for bilateral measurements simulated LC measurements were similar to PSP but less accurate, underestimating dimensions by between 4.7% to 17%.For 3D volumetric renderings, 2/3 rd of CBCT measurements are statistically different from actual measurements, however this possibly is not clinically relevant

Comparative linear accuracy of cone beam CT derived 3D images in orthodontic analysis.

Objective . To compare the in vitro reliability and accuracy of linear measurements between cephalometric landmarks on CBCT 3D images with varying basis projection images to direct measurements on human skulls. Methods . Sixteen linear dimensions between anatomical sites marked on 19 human skulls were directly measured. Skulls were imaged with CBCT at three settings: 153, 306, and 612 basis projections. The mean absolute error and modality mean of linear measurements between landmarks on 3D images were compared to the anatomic truth. Results . No difference in mean absolute error between the scan settings was found. The average skull absolute error between marked reference points were less than the distances between unmarked reference sites. Conclusion . CBCT measurements were consistent between scan sequences and for direct measurements between marked reference points. Reducing the number of projections for 3D reconstruction did not lead to reduced dimensional accuracy and potentially provides reduced patient radiation exposure

Facial Reconstruction: A Systematic Review of Current Image Acquisition and Processing Techniques

Plastic and reconstructive surgery is based on a culmination of technological advances, diverse techniques, creative adaptations and strategic planning. 3D imaging is a modality that encompasses several of these criteria while encouraging the others. Imaging techniques used in facial imaging come in many different modalities and sub-modalities which is imperative for such a complex area of the body; there is a clear clinical need for hyper-specialized practice. However, with this complexity comes variability and thus there will always be an element of bias in the choices made for imaging techniques

AUTOMATIC RECOGNITION OF DENTAL PATHOLOGIES AS PART OF A CLINICAL DECISION SUPPORT PLATFORM

The current work is done within the context of Romanian National Program II (PNII) research project "Application for Using Image Data Mining and 3D Modeling in Dental Screening" (AIMMS). The AIMMS project aims to design a program that can detect anatomical information and possible pathological formations from a collection of digital imaging and communications in medicine (DICOM) images. The main function of the AIMMS platform is to provide the user with the opportunity to use an integrated dental support platform, using image processing techniques and 3D modeling. From the literature review, it can be found that for the detection and classification of teeth and dental pathologies existing studies are in their infancy. Therefore, the work reported in this article makes a scientific contribution in this field. In this article it is presented the relevant literature review and algorithms that were created for detection of dental pathologies in the context of research project AIMMS

Analysis of orbital floor blowout fractures using anonymized computed tomography scans

The orbits are bony structures of the skull that house the globe, extraocular muscles, nerves, blood vessels, lacrimal apparatus, and adipose tissue. Each orbit protects the globe, while the supportive tissues allow the globe to move in three dimensions (horizontal, vertical, and torsional). The orbital floor comprises the maxillary, palatine, and zygomatic bones, and the walls of the orbit function as a physical barrier from blunt trauma to the eye, an anchor for muscles and ligaments to attach, and additionally serve as a window for neurovasculature to travel through. Because of its position and its thin bony walls, it is susceptible to fractures, and in a lot of cases surgery is required as part of the treatment to repair the resulting defect with an implant. In this context, the present work had the purpose to analyze medical computed tomography (CT) and cone beam computed tomography (CBCT) – also called digital volume tomography (DVT) - imaging data from anonymized patients with orbital floor defects for the measurement of the length, the depth, the total area, and the defect area of them using the software called VG STUDIOMAX (Volume Graphics GmbH, Heildelberg, Germany) designed for industrial CT examinations. The analysis of medical imaging data is equally possible, but new for the case of orbital floor defects. The method was successfully done, and some of the results obtained on this work are similar to the values obtained on the literature. The main values obtained for length measurements of total orbital floor were 28,18 ± 2,93 mm and 27,93 ± 2,70 mm for left and right side respectively (p = 0,83). The main values obtained for depth measurements of total orbital floor were 29,80 ± 2,80 mm and 29,40 ± 3,03 mm for left and right side respectively (p = 0,74). The main values obtained for length and depth of orbital floor defects were 13,61 ± 4,98 and 17,38 ± 5,82 respectively (p = 0,14). By conventional criteria, these differences are considered to be not statistically significant showing reproducible results, however, no studies were found to compare it with. The main values obtained for total surface area were 632,89 ± 147,44 mm² and 641,76 ± 150,09 mm² for left and right side respectively (p = 0,88) and the main value obtained for defect surface area 403,28,32 ± 132,15 mm², being similar to other studies. The mean value for defect and total area ratio obtained on this work, 65,00 ± 15,00, a little higher than the ones calculated on the other studies found in literature.As órbitas são estruturas ósseas do crânio que abrigam o globo terrestre, músculos extraoculares, nervos, vasos sanguíneos, aparelho lacrimal e tecido adiposo. Cada órbita protege o globo ocular, enquanto os tecidos de suporte permitem que o globo se mova em três dimensões (horizontal, vertical e de torção). O piso (ou assoalho) orbital compreende os ossos maxilares, palatinos e zigomáticos, e as paredes da órbita funcionam como uma barreira física contra traumas no olho, uma âncora para os músculos e ligamentos se fixarem, e adicionalmente servem como uma janela para a neurovasculatura viajar através. Devido a sua posição e suas finas paredes ósseas, é suscetível a fraturas e, em muitos casos, é necessária cirurgia como parte do tratamento para reparar o defeito resultante com um implante. Neste contexto, o presente trabalho teve a finalidade de analisar imagens de tomografia computadorizada médica (TC) e de tomografia computadorizada de feixe cônico (TCFC) - também chamada tomografia digital de volume (TDV) – de pacientes anônimos com defeitos no piso orbital para a medição do comprimento, da profundidade, da área total e da área defeituosa dos mesmos, utilizando o software chamado VG STUDIOMAX (Volume Graphics GmbH, Heildelberg, Alemanha) projetado para exames de TC industriais. A análise de dados de imagens médicas é igualmente possível, mas nova para o caso de defeitos orbitais do piso. O método foi realizado com sucesso e alguns dos resultados obtidos neste trabalho são semelhantes aos valores obtidos na literatura. Os valores médios obtidos para as medidas de comprimento do piso orbital total foram 28,18 ± 2,93 mm e 27,93 ± 2,70 mm para os lados esquerdo e direito respectivamente (p = 0,83). Para as medidas de profundidade do piso orbital total obteve-se 29,80 ± 2,80 mm e 29,40 ± 3,03 mm para os lados esquerdo e direito respectivamente (p = 0,74). Para as medidas de comprimento e profundidade dos defeitos do piso orbital obteve-se 13,61 ± 4,98 e 17,38 ± 5,82 respectivamente (p = 0,14). Por critérios convencionais, estas diferenças são consideradas como não estatisticamente significativas mostrando resultados reprodutíveis, entretanto, não foram encontrados estudos para compará-los. Os valores obtidos para a área de superfície total foram 632,89 ± 147,44 mm² e 641,76 ± 150,09 mm² para os lados esquerdo e direito respectivamente (p = 0,88) e o valor obtido para a área de superfície do defeito foi 403,28 ± 132,15 mm², sendo similares a outros estudos. O valor médio para a razão entre o defeito e a área total obtido neste trabalho foi de 65,00 ± 15,00, um pouco maior do que os valores calculados em outros estudos encontrados na literatura