Los sistemas de imágenes de alta tecnología en la cirugía de catarata / High-technology imaging systems in cataract surgery

La cirugía de catarata actual se ha convertido en una cirugía refractiva, pues se busca además la corrección del defecto refractivo tanto esférico como cilíndrico en el mismo proceder y, por tanto, la emetropía sin corrección óptica en todas las distancias. Para esto debemos tener una verdadera lectura del astigmatismo corneal total y una identificación correcta del meridiano a tratar. Hoy en día existen dispositivos de avanzada tecnología capaces de brindar estos y otros datos preoperatorios e intraoperatorios de gran confiabilidad. Algunos de estos sistemas como Verion, Callisto Eye y el TrueGuide, utilizan la topografía corneal con registro del limbo y, luego de capturar una imagen preoperatoria, la recuerdan durante la cirugía para generar el meridiano objetivo en un monitor o a través del microscopio quirúrgico, y de esta manera ayudar en la alineación precisa de la lente intraocular tórica. Incluso pueden ofrecer imágenes tridimensionales en vivo. Otros, por su parte, utilizan la aberrometría de frente de onda intraoperatoria para ayudar al cirujano a elegir el poder de la lente intraocular tórica y luego alinearla, como los sistemas ORA y Holos IntraOp. Estos instrumentos proporcionan retroalimentación refractiva continua en tiempo real para la corrección astigmática en el mismo acto quirúrgico. Sin dudas, estos sistemas son parte de una revolución tecnológica dentro del campo de la cirugía del cristalino actual que posibilitan una mayor precisión y predicción de los resultados refractivos y constituyen elementos imprescindibles si queremos conseguir una cirugía de catarata de excelencia. Se realiza esta revisión con el objetivo de obtener información acerca de los sistemas de imágenes de alta tecnología que se usan hoy día en la cirugía del cristalino y mostrar sus potencialidades para obtener resultados refractivos posoperatorios más exactos(AU)

Current cataract surgery has become refractive surgery, for it is also aimed at correcting both spherical and cylindrical refractive defects in the same procedure, thus achieving emmetropia without optical correction at all distances. For this we must have a true reading of the total corneal astigmatism and a correct identification of the meridian to be treated. Today there are advanced technological devices capable of providing these and other preoperative and intraoperative data with great reliability. Some of these systems, such as Verion, Callisto Eye and TrueGuide, use corneal topography with limbus registration and after capturing a preoperative image, they remember it during surgery to generate the target meridian on a monitor or through the surgical microscope, thus helping achieve precise alignment of the toric intraocular lens. They can even offer live three-dimensional images. Others, such as the ORA and Holos IntraOp systems, use intraoperative wavefront aberrometry to help the surgeon choose the power of the toric intraocular lens and then align it. These instruments provide continuous refractive feedback in real time for astigmatic correction in the same surgical act. Undoubtedly, these systems are part of a technological revolution within the field of current crystalline lens surgery that enable greater precision and prediction of refractive results and are essential elements if we want to achieve cataract surgery of excellence. This review was conducted to obtain information about high-technology imaging systems currently used in crystalline lens surgery, and show their potential to achieve more accurate postoperative refractive results(AU)

Actualidad de la cirugía robótica / Present time of the robotic surgery

Introducción: la cirugía robótica es ya una realidad. Aunque la historia de la cirugía se remonta a más de 2000 años; las últimas dos décadas del siglo XX han mostrado una marcada revolución en la medicina, debido a todos los cambios que ha provocado en la manera de hacer, enseñar y practicar la cirugía. Objetivo: exponer aspectos generales y actuales de la robótica aplicada a la medicina y en especial a la cirugía; así como el impacto que la cirugía robótica ha tenido en la enseñanza médica. Métodos: se realizó una revisión sistemática a partir de la consulta de artículos científicos indexados relacionados con el tema. Las fuentes de información consultadas fueron: Pubmed, Ebsco y Scielo. La información se analizó y seleccionó en correspondencia con el tema y los objetivos. Resultados: la cirugía robótica ha evolucionado hasta ser un campo aparte con un enorme potencial para su desarrollo presente y futuro. Los robots que se utilizan para este tipo de cirugías han tenido una gran aceptación en la comunidad científica por las ventajas significativas como la posibilidad de llegar a partes del cuerpo donde un humano no podría llegar y accionar. Conclusiones: esta revisión muestra que la tecnología robótica es capaz de ofrecer resultados satisfactorios y un adecuado tratamiento a los pacientes. Esto garantiza un riesgo de intervención mucho menor y una óptima recuperación en el menor tiempo posible, al crearse programas muy eficaces para su aprendizaje(AU)

Introduction: Robotic surgery is already a reality. Although surgery history dates back from more than 2000 years, the last two decades of the twentieth century have shown a marked revolution in medicine, due to all the changes it has caused in the way of doing, teaching and practicing surgery. Objective: To present general and current aspects of robotics applied to medicine and especially to surgery, as well as the impact of robotic surgery in medical teaching. Methods: A systematic review was carried out based on the consultation of indexed scientific articles related to the topic. The sources of information consulted were PubMed, Ebsco and Scielo. The information was analyzed and chosen in correspondence with the topic and objectives. Results: Robotic surgery has evolved into a separate field with enormous potential for its present and future development. The robots used for this type of surgeries have had a great acceptance among the scientific community, for the significant advantages, such as the possibility to arrive at body areas a human could not arrive and act on. Conclusions: This review shows that robotic technology is able to offer patients satisfactory outcomes and adequate treatment. This guarantees a much lower intervention risk and an optimum recovery in the shortest possible time, creating very effective programs for their learning(AU)

Risco de perda óssea de implantes cone-morse, hexágono externo e interno em próteses totais fixas na maxila ­ análise por elementos finitos 3D / Risk of bone loss for morse taper, external, and internal hexagon dental implants in complete fixed implant-supported prostheses ­ a 3D finite element analysis

Objetivo: analisar comparativamente o risco de perda óssea peri-implantar em próteses totais fixas na maxila, suportadas por seis implantes paralelos, utilizando conexões do tipo hexágono externo (HE), hexágono interno (HI) e cone-morse (CM) através do método dos elementos finitos 3D. Material e métodos: modelos geométricos de uma maxila e prótese foram construídos e unidos aos modelos de implantes de geometria externa semelhante para representar próteses totais maxilares parafusadas, suportadas por seis implantes paralelos cada uma. Os modelos foram submetidos a cargas mastigatórias axiais e oblíquas. Resultados: o risco de perda óssea na carga oblíqua é muito superior à carga axial; nessa condição, a conexão CM apresentou o menor risco de perda óssea e as conexões HE e HI apresentaram risco semelhante, com risco ligeiramente maior do HI. Conclusão: implantes com conexão CM apresentam menor risco de perda óssea peri-implantar, e implantes com conexão HE e HI apresentam risco similar em próteses totais fixas com implantes paralelos.

Objective: to analyze the risk of peri-implant bone loss in complete fixed, implant-supported prosthesis over six parallel implants using the external hex (EH), internal hex (IH), and morse cone (CM) connections through a 3D finite element method. Material and methods: geometric models of a maxilla and prosthesis were constructed and attached to implant models with similar external geometry to represent maxillary screw-retained dentures supported by six parallel implants each. The models were submitted to axial and oblique masticatory loads. Results: the risk of bone loss under oblique loading is higher than for axial loading; in this condition, the CM connections demonstrated the lowest risk of bone loss, with EH and IH connections showing similar risks, although slightly higher for IH. Conclusion: CM implants present less risk for peri-implant bone loss, and the EH and IH had similar values for complete fixed implant-supported restorations over parallel dental implants.

Distribuição de tensões em um modelo tridimensional de canino e pré-molares superiores sob diferentes carregamentos oclusais: análise pelo método de elementos finitos / Stress distribution in a three-dimensional model of canine and premolars superiors under different occlusal loads: analysis by finite element method

O objetivo desse estudo foi analisar, por meio do Método de Elementos Finitos, a distribuição de tensões na estrutura dentária, no ligamento periodontal (LP) e no osso alveolar em um modelo tridimensional do canino (23), primeiro (24) e segundo pré-molares superiores (25) submetidos à ação de cargas axiais e oblíquas. Além disso, objetivou-se avaliar a influência do ponto de contato proximal na distribuição das tensões no modelo de três dentes (M1), comparado a um modelo unitário do 24 (M2). As propriedades mecânicas bem como as condições de contorno e carregamento foram determinadas no programa de elementos finitos Ansys®. Cargas axiais e oblíquas foram aplicadas nas seguintes simulações: C1) Carga axial nos contatos A e B no dente 24; C2) Contato excêntrico no dente 24; C3) Carga oblíqua de 45N, com inclinação de 45o no contato A do dente 24; C4) Carga oblíqua de 45N, com inclinação de 45o no contato B do dente 24; C5) Cargas axiais simultâneas, de 70N na ponta de cúspide do dente 23, 90N nos contatos A e B do dente 24 e de 105N nos contaos A e B do dente 25. Para estimar a possibilidade de falha no esmalte, as tensões máximas principais foram analisadas e deformações máximas e mínimas principais foram analisadas no LP e no osso alveolar, sendo que ambos foram comparados a valores encontrados em outros estudos com metodologia similar. Em C1, a distribuição de tensões foi mais favorável para as estruturas dente-LP-osso, com picos de tensões semelhantes em M1 e M2. Em C2, tensões deslocaramse para apical, devido ao contato entre os dentes 24 e 23 em M1; os picos de tensões foram maiores em M1 do que em M2 no esmalte e no osso e o inverso ocorreu na dentina e no LP. Em C3, tensões de tração concentraram-se na região cervical do esmalte e na furca do dente 24; os picos das tensões no esmalte, osso e LP foram menores em M1 comparado a M2, mas na dentina ocorreu o contrário (M1>M2). Em C4, ocorreu o maior pico de tensão de tração no esmalte, tensões de tração concentraram-se na furca do dente 24; esmalte e dentina comportaram-se de forma similar (M1>M2) e osso e LP também (M1˂M2). Em C5, tensões de tração se concentraram no osso alveolar do dente 23. Os contatos proximais em M1 permitiram a distribuição das tensões de forma mais homogênea para o LP e osso que em M2. Exceto em C1, a distribuição de tensões no esmalte cervical, na dentina, no LP e no osso alveolar diferiram em um modelo unitário comparado a um de três dentes, devido à presença dos contatos proximais.

The direction, type and magnitude of loads on the oclusal surface and also the characteristics of the support structures determines the stress distribution. The aim of this study was to analyze, by the finite element method, the stress distribution on the first superior premolar, in a tridimensional (3D) model subjected to various types of loadings considering the enamel anisotropic or isotropic. The geometric modeling was performed based on a computed tomography (CT) scan. The mechanical properties as well as the loading conditions determined by the Abaqus® finite element program. Axial and oblique loads were applied on the occlusal surface of the first superior premolar in the following conditions: I) 30N axial load applied simultaneously on the occlusal contacts A and B and in the mesial marginal ridge, totaling 90N; II) 90N axial load in the mesial longitudinal edge of the lingual cusp, simulating eccentric contact; III) 45N oblique load with a 45o inclination on theocclusal contact A; IV) 45N oblique load with a 45o inclination on the occlusal contact B. To estimate the possibility of failure in the simulated structures, the maximum principal stress were analyzed and compared to known tensile strength values of the tissues studied. The results showed compression stress on the side in which the load was applied and tensile stress on the opposite side. Tensile stress concentrates mainly in the cervical region of the tooth and in the alveolar insertion bone. Anisotropic models revealed areas of tensile stress concentration smaller than the isotropic models. It was concluded that the isotropic 3D models were suitable for analyzing the stress distribution in teeth, because they are less complex models to build and produced similar results compared to the anisotropic models. The cervical enamel seems to be more susceptible to fracture because of the largest stress concentration on this area, associated with its composition and anatomical characteristics

Biomecânica da união dente-implante com plataforma restauradora reduzida, sistema de retenção tipo cone morse e roscas quadradas: uma análise por elementos finitos / Biomechanics of tooth-implant union with restorative platform reduced, restraint system morse cone type and square threads: a finite element analysis

Objetivou-se, a partir do Método dos Elementos Finitos, avaliar a biomecânica da união dente-implante e implante-implante, além de estabelecer uma análise qualitativa com achados fotoelásticos prévios. Foram planejados quatro modelos tridimensionais: dois Modelos Teste (dentes unidos a implantes) e dois Modelos Controle (a mesma condição, porém implanto suportada). Os implantes (ANKYLOS® - Dentsply) apresentaram conexão cônica, roscas quadradas e pilares Switching. Suas dimensões, ângulos externos e pilares protéticos foram obtidos a partir de um projetor de perfil. Já, dentes e próteses, a partir da visão direta, tiveram suas formas externas construídas em plataforma CAD (SOLIDSWORKS). O suporte alveolar foi configurado como um retângulo (68/30/15 mm). Todos os pilares foram posicionados no suporte alveolar, conforme os modelos físicos pré-existentes, gerando modelos sólidos. O ligamento periodontal consistiu de uma camada de 0,25 mm de espessura em poliéter (Impregum Soft, 3M Espe). Os modelos de dentes foram produzidos em dentina, pilares e implantes em titânio puro, próteses em liga Níquel-Cromo (Ni-Cr), e o suporte alveolar em resina fotoelástica (Araldite® - Produtos Químicos Ciba S/A do Brasil). As propriedades da resina foram obtidas por meio de ensaio de tração. Carga pontual, vertical e estática, de 150 N, foi aplicada. Os resultados destes ensaios evidenciaram menor concentração de tensão no aspecto cervical de implantes do grupo teste. Ao se confrontar tais achados com os fotoelásticos anteriormente obtidos, foi possível estabelecer uma relação direta entre as áreas mais solicitadas para os modelos de prótese fixa (PF) de três elementos. Concluiu-se que, para as condições estudadas ¿ conexão cônica, roscas quadradas e restauração com Plataforma Switching ¿, unir dentes a implantes parece ser uma terapia clínica viável, sugerindo, inclusive, ser mais favorável que a união de implantes entre si. Além disso, a partir da afinidade positiva entre os achados das duas técnicas, pôde-se considerar validados os modelos matemáticos de prótese fixa de três elementos

The goal of this study was to evaluate, from the Finite Element Method, the biomechanics of implant-tooth union and implant-implant and to establish a qualitative analysis with previous photoelastic findings. Four three-dimensional models were planned: two Test Models (teeth attached to implants) and two Control Models (the same condition, however implant supported). The implants (ANKYLOS® - Dentsply) showed conical connection, square threads and Switching pillars. Their dimensions, external angles and abutments were obtained from a profile projector. Already, teeth and dentures, from direct view, had their external forms built in CAD platform (SOLIDSWORKS). Alveolar support wasconfigured as a rectangle (68/30/15 mm). All the pillars were placed in the alveolar support, as the pre-existing physical models, generating solid models. The periodontal ligament consists of a layer of 0.25 mm thick in polyether (Impregum Soft, 3M Espe). The models of teeth trumped up of dentin, abutments and implants of pure titanium, prosthetics of Nickel-Chrome (Ni-Cr) alloy and alveolar support in photoelastic resin (Araldite® - Chemicals Ciba S/A of Brazil). The resin properties were obtained by traction tests. Punctual and vertical static load of 150 N was applied. The results of these tests showed lower concentration of tension in the cervical aspect of the test group implants. When comparing these findings with the photoelastic previously found, it was possible to establish a direct relation between the areas most requested for fixed prosthesis (FP) models of three elements. It was concluded that, for the studied conditions tapered connection, square threads and Platform Switching restoration , joining teeth implants seems to be a viable clinical therapy, suggesting, inclusive, to be more favorable than to join implants each other. Moreover, from the positive affinity between the findings of the two techniques, it was possible to consider validated the mathematical models of fixed prosthesis of three elements

Measurement accuracy and reliability of tooth length on conventional and CBCT reconstructed panoramic radiographs

INTRODUCTION: This in vivo study assessed accuracy and reliability of tooth length measurements obtained from conventional panoramic radiographs and CBCT panoramic reconstructions to that of a digital caliper (gold standard). METHODS: The sample consisted of subjects who had CBCT and conventional panoramic radiographic imaging and who required maxillary premolar extraction for routine orthodontic treatment. A total of 48 teeth extracted from 26 subjects were measured directly with digital calipers. Radiographic images were scanned and digitally measured in Dolphin 3D software. Accuracy of tooth length measurements made by CBCT panoramic reconstructions, conventional panoramic radiographs and digital caliper (gold standard) were compared to each other by repeated measures one-way ANOVA with Bonferroni correction and by single measures intraclass correlation coefficient. RESULTS: Repeated root length measures with digital calipers, panoramic radiographs and CBCT constructed panoramic-like images were all individually highly reliable. Compared to the caliper (gold standard), tooth measurements obtained from conventional panoramic radiographs were on average 6.3 mm (SD = 2.0 mm) longer, while tooth measurements from CBCT panoramic reconstructions were an average of 1.7 mm (SD = 1.2 mm) shorter. CONCLUSIONS: In comparison to actual tooth lengths, conventional panoramic radiographs were relatively inaccurate, overestimating the lengths by 29%, while CBCT panoramic reconstructions underestimated the lengths by 4%. .

INTRODUÇÃO: este estudo in vivo avaliou a precisão e a confiabilidade de medições do comprimento dentário realizadas em radiografias panorâmicas convencionais e em reconstruções panorâmicas de tomografias computadorizadas de feixe cônico (TCFC), comparando-as com medições feitas com um paquímetro digital, consideradas o padrão-ouro. MÉTODOS: a amostra incluiu indivíduos que já tivessem realizado tanto exames imaginológicos de TCFC quanto radiografias panorâmicas, e cujo tratamento ortodôntico exigisse a extração de pré-molar superior. No total, 48 dentes extraídos, de 26 pacientes, foram mensurados diretamente com paquímetros digitais. As radiografias foram escaneadas e digitalmente avaliadas com a ajuda do software Dolphin 3D. Por meio da análise de variância simples com correção de Bonferroni e Coeficiente de Correlação Intraclasse simples, comparou-se a precisão das medições de comprimento dentário realizadas em reconstruções panorâmicas de TCFC, em radiografias panorâmicas convencionais e com paquímetro digital. RESULTADOS: medições repetidas de comprimento dentário feitas com o paquímetro digital, radiografias panorâmicas e reconstruções panorâmicas de TCFC foram todas consideradas, individualmente, altamente confiáveis. Em comparação ao paquímetro, as medidas obtidas por meio de radiografias panorâmicas convencionais foram, em média, 6,3 ± 2,0mm mais longas, enquanto as medidas obtidas por meio das reconstruções panorâmicas de TCFC foram, em média, 1,7 ± 1,2mm mais curtas. CONCLUSÕES: em comparação com o real comprimento dentário, as radiografias panorâmicas convencionais foram relativamente ...

Anatomical and functional characteristics of the pelvic floor in nulliparous women submitted to three-dimensional endovaginal ultrasonography: case control study and evaluation of interobserver agreement / Características anatômicas e funcionais do assoalho pélvico em nulíparas avaliadas por ultrassonografia tridimensional endovaginal: estudo caso-controle e avaliação da confiabilidade interobservador

PURPOSE: To determine anatomical and functional pelvic floor measurements performed with three-dimensional (3-D) endovaginal ultrasonography in asymptomatic nulliparous women without dysfunctions detected in previous dynamic 3-D anorectal ultrasonography (echo defecography) and to demonstrate the interobserver reliability of these measurements. METHODS: Asymptomatic nulliparous volunteers were submitted to echo defecography to identify dynamic dysfunctions, including anatomical (rectocele, intussusceptions, entero/sigmoidocele and perineal descent) and functional changes (non-relaxation or paradoxical contraction of the puborectalis muscle) in the posterior compartment and assessed with regard to the biometric index of levator hiatus, pubovisceral muscle thickness, urethral length, anorectal angle, anorectal junction position and bladder neck position with the 3-D endovaginal ultrasonography. All measurements were compared at rest and during the Valsalva maneuver, and perineal and bladder neck descent was determined. The level of interobserver agreement was evaluated for all measurements. RESULTS: A total of 34 volunteers were assessed by echo defecography and by 3-D endovaginal ultrasonography. Out of these, 20 subjects met the inclusion criteria. The 14 excluded subjects were found to have posterior dynamic dysfunctions. During the Valsalva maneuver, the hiatal area was significantly larger, the urethra was significantly shorter and the anorectal angle was greater. Measurements at rest and during the Valsalva maneuver differed significantly with regard to anorectal junction and bladder neck position. The mean values for normal perineal descent and bladder neck descent were 0.6 cm and 0.5 cm above the symphysis pubis, respectively. The intraclass correlation coefficient ranged from 0.62-0.93. CONCLUSIONS: Functional biometric indexes, normal perineal descent and bladder neck descent values were determined for young asymptomatic nulliparous women with the 3-D endovaginal ultrasonography. The method was found to be reliable to measure pelvic floor structures at rest and during Valsalva, and might therefore be suitable for identifying dysfunctions in symptomatic patients.

OBJETIVO: Avaliar as medidas anatômicas e funcionais do assoalho pélvico utilizando a ultrassonografia tridimensional transvaginal em nulíparas assintomáticas sem disfunções do compartimento posterior evidenciado pela ecodefecografia. Demonstrar o grau de concordância entre observadores do método utilizado para medir as estruturas anatômicas. MÉTODOS: Voluntárias nulíparas assintomáticas foram submetidas à ecodefecografia para identificar alterações dinâmicas no compartimento posterior, incluindo aquelas anatômicas (retocele, intussuscepção, entero/sigmoidocele e descenso perineal) e funcionais (ausência de relaxamento ou contração paradoxal do puborretal) e avaliadas com ultrassonografia tridimensional transvaginal para determinar índices biométricos do hiato dos elevadores do ânus, espessura do músculo pubovisceral, comprimento da uretra, ângulo anorretal, posição da junção anorretal e posição do colo vesical. Todas as medidas foram comparadas em repouso e durante Valsalva; e determinado descenso perineal e do colo da bexiga. A variabilidade interobservador foi avaliada utilizando o coeficiente de correlação intraclasse. RESULTADOS: Foram avaliadas 34 voluntárias com a ecodefecografia e a ultrassonografia tridimensional transvaginal. Dessas, 20 foram incluídas no estudo. As 14 excluídas apresentavam alterações dinâmicas no compartimento posterior. Durante a manobra de Valsalva, a área hiatal foi significativamente maior. A uretra foi significantemente mais curta e o ângulo anorretal foi maior. Medidas em repouso e durante a Valsalva diferiram significativamente em relação à posição da junção anorretal e do colo vesical. A média de valor do descenso perineal e do descenso da bexiga foram de 0,6 cm e 0,5 cm acima da sínfise púbica, respectivamente. O coeficiente de correlação intraclasse variou entre 0,62-0,93. CONCLUSÕES: Foram determinados valores normais para os índices biométricos funcionais, descida perineal e colo vesical em nulíparas assintomáticas utilizando-se a ultrassonografia transvaginal tridimensional. É um método seguro para mensurar a anatomia do assoalho pélvico durante o repouso e a manobra de Valsalva, e pode ser adequado para a identificação de disfunções em pacientes sintomáticos.

Mathematical models for teenager's living age evaluation based on CT image of medial clavicular epiphysis / 法医学杂志

OBJECTIVE@#To explore the correlation between volume rendering (VR) statistics of medial clavicular epiphysis and living age, and establish the mathematical models for living age evaluation using the CT image of medial clavicular epiphysis based on the growth rules of osteoepiphysis of medial clavicle.@*METHODS@#The CT images of the medial clavicles from 795 teenagers aged 15-25, 387 males and 408 females, were collected in East and South China. VR 3D images were reconstructed from 0.60 mm-thick slice CT images. The epiphyseal diameter, sternal end diameter, and their respective diameter ratio (the left: X1; the right: x3); epiphyseal area, sternal end area, and their respective area ratio (the left: x2; the right: x4), were measured and calculated. All these observations were analyzed using SPSS 19.0 statistical software. The statistical differences in gender and age were analyzed by Mann-Whitney U test. The mathematical models were established using least square. Sixty trained subjects, 30 males and 30 females, were tested to verify the accuracy of the established mathematical models.@*RESULTS@#In the group of same age, x1 showed significant difference in gender; the same results were observed in x2, x3, and x4, which suggested that the growth rules of osteoepiphysis of medial clavicle were highly correlated with living age. The accuracy of these mathematical models were all above 67.6% (+/- 1.0 year) and 78.5% (+/- 1.5 year).@*CONCLUSION@#The mathematical models with reasonable accuracy could be manageable in practice to confirm the conclusion of the atlas method. The current study can contribute to the single skeletal age evaluation.

Comparative Analysis of Logistic Regression, Support Vector Machine and Artificial Neural Network for the Differential Diagnosis of Benign and Malignant Solid Breast Tumors by the Use of Three-Dimensional Power Doppler Imaging

OBJECTIVE: Logistic regression analysis (LRA), Support Vector Machine (SVM) and a neural network (NN) are commonly used statistical models in computer-aided diagnostic (CAD) systems for breast ultrasonography (US). The aim of this study was to clarify the diagnostic ability of the use of these statistical models for future applications of CAD systems, such as three-dimensional (3D) power Doppler imaging, vascularity evaluation and the differentiation of a solid mass. MATERIALS AND METHODS: A database that contained 3D power Doppler imaging pairs of non-harmonic and tissue harmonic images for 97 benign and 86 malignant solid tumors was utilized. The virtual organ computer-aided analysis-imaging program was used to analyze the stored volumes of the 183 solid breast tumors. LRA, an SVM and NN were employed in comparative analyses for the characterization of benign and malignant solid breast masses from the database. RESULTS: The values of area under receiver operating characteristic (ROC) curve, referred to as Az values for the use of non-harmonic 3D power Doppler US with LRA, SVM and NN were 0.9341, 0.9185 and 0.9086, respectively. The Az values for the use of harmonic 3D power Doppler US with LRA, SVM and NN were 0.9286, 0.8979 and 0.9009, respectively. The Az values of six ROC curves for the use of LRA, SVM and NN for non-harmonic or harmonic 3D power Doppler imaging were similar. CONCLUSION: The diagnostic performances of these three models (LRA, SVM and NN) are not different as demonstrated by ROC curve analysis. Depending on user emphasis for the use of ROC curve findings, the use of LRA appears to provide better sensitivity as compared to the other statistical models.