Abstract Background: Neuroimaging strategies are essential to locate, to elucidate the etiology, and to the follow up of brain disease patients. Magnetic resonance imaging (MRI) provides good cerebral soft-tissue contrast detection and diagnostic sensitivity. Inflammatory lesions and tumors are common brain diseases that may present a similar pattern of a cerebral ring enhancing lesion on MRI, and non-enhancing core (which may reflect cystic components or necrosis) leading to misdiagnosis. Texture analysis (TA) and machine learning approaches are computer-aided diagnostic tools that can be used to assist radiologists in such decisions. Methods: In this study, we combined texture features with machine learning (ML) methods aiming to differentiate brain tumors from inflammatory lesions in magnetic resonance imaging. Retrospective examination of 67 patients, with a pattern of a cerebral ring enhancing lesion, 30 with inflammatory, and 37 with tumoral lesions were selected. Three different MRI sequences and textural features were extracted using gray level co-occurrence matrix and gray level run length. All diagnoses were confirmed by histopathology, laboratorial analysis or MRI. Results: The features extracted were processed for the application of ML methods that performed the classification. T1-weighted images proved to be the best sequence for classification, in which the differentiation between inflammatory and tumoral lesions presented high accuracy (0.827), area under ROC curve (0.906), precision (0.837), and recall (0.912). Conclusion: The algorithm obtained textures capable of differentiating brain tumors from inflammatory lesions, on T1-weghted images without contrast medium using the Random Forest machine learning classifier.

RESUMO Objetivo: O objetivo deste estudo foi desenvolver e validar uma ferramenta computacional para auxiliar as decisões radiológicas na enterocolite necrotizante. Metodologia: Pacientes que exibiam sinais clínicos e evidências radiográficas do estágio 2 ou superior de Bell foram incluídos no estudo, que resultou em 64 exames. A ferramenta foi usada para classificar o aumento localizado da espessura da parede intestinal e a pneumatose intestinal com medidas de largura total a meia altura e análises de textura baseadas na decomposição da energia wavelet. Os achados radiológicos de aumento suspeito da espessura da parede intestinal e das alças na pneumatose intestinal foram confirmados pela cirurgia e análise histopatológica do paciente. Dois radiologistas experientes selecionaram um intestino afetado e um intestino normal na mesma radiografia. A largura total a meia altura e a característica da textura baseada em wavelet foram então calculadas e comparadas com o uso do teste U de Mann-Whitney. Foram calculados a especificidade, sensibilidade, valores preditivos positivos e negativos. Resultados: Os resultados da largura total a meia altura foram significativamente diferentes entre a alça normal e a distendida (mediana de 10,30 e 15,13, respectivamente). Medidas de energia wavelet horizontal, vertical e diagonal foram avaliadas em oito níveis de decomposição. Os níveis 7 e 8 na direção horizontal apresentaram diferenças significativas. Para o nível 7, as medianas foram 0,034 e 0,088 para os grupos normal e com pneumatose intestinal, respectivamente, e para o nível 8, as medianas foram 0,19 e 0,34, respectivamente. Conclusões: A ferramenta desenvolvida pode detectar diferenças nos achados radiográficos do aumento da espessura da parede intestinal e PI de difícil diagnóstico, demonstra seu potencial na rotina clínica. A ferramenta desenvolvida no presente estudo pode ajudar os médicos a investigar alças intestinais suspeitas e melhorar consideravelmente o diagnóstico e as decisões clínicas.

ABSTRACT Objective: The objective of this study was to develop and validate a computational tool to assist radiological decisions on necrotizing enterocolitis. Methodology: Patients that exhibited clinical signs and radiographic evidence of Bell's stage 2 or higher were included in the study, resulting in 64 exams. The tool was used to classify localized bowel wall thickening and intestinal pneumatosis using full-width at half-maximum measurements and texture analyses based on wavelet energy decomposition. Radiological findings of suspicious bowel wall thickening and intestinal pneumatosis loops were confirmed by both patient surgery and histopathological analysis. Two experienced radiologists selected an involved bowel and a normal bowel in the same radiography. The full-width at half-maximum and wavelet-based texture feature were then calculated and compared using the Mann-Whitney U test. Specificity, sensibility, positive and negative predictive values were calculated. Results: The full-width at half-maximum results were significantly different between normal and distended loops (median of 10.30 and 15.13, respectively). Horizontal, vertical, and diagonal wavelet energy measurements were evaluated at eight levels of decomposition. Levels 7 and 8 in the horizontal direction presented significant differences. For level 7, median was 0.034 and 0.088 for normal and intestinal pneumatosis groups, respectively, and for level 8 median was 0.19 and 0.34, respectively. Conclusions: The developed tool could detect differences in radiographic findings of bowel wall thickening and IP that are difficult to diagnose, demonstrating the its potential in clinical routine. The tool that was developed in the present study may help physicians to investigate suspicious bowel loops, thereby considerably improving diagnosis and clinical decisions.

Abstract Background: Background: Tuberculosis (TB) is an infectious lung disease with high worldwide incidence that severely compromises the quality of life in affected individuals. Clinical tests are currently employed to monitor pulmonary status and treatment progression. The present study aimed to apply a three-dimensional (3D) reconstruction method based on chest radiography to quantify lung-involvement volume of TB acute-phase patients before and after treatment. In addition, these results were compared with indices from conventional clinical exams to show the coincidence level. Methods: A 3D lung reconstruction method using patient chest radiography was applied to quantify lung-involvement volume using retrospective examinations of 50 patients who were diagnosed with pulmonary TB and treated with two different drugs schemes. Twenty-five patients were treated with Scheme I (rifampicin, isoniazid, and pyrazinamide), whereas twenty-five patients were treated with Scheme II (rifampicin, isoniazid, pyrazinamide, and ethambutol). Acute-phase reaction: Serum exams included C-reactive protein levels, erythrocyte sedimentation rate, and albumin levels. Pulmonary function was tested posttreatment. Results: We found strong agreement between lung involvement and serum indices pre- and posttreatment. Comparison of the functional severity degree with lung involvement based on 3D image quantification for both treatment schemes found a high correlation. Conclusions: The present 3D reconstruction method produced a satisfactory agreement with the acute-phase reaction, most notably a higher significance level with the C-reactive protein. We also found a quite reasonable coincidence between the 3D reconstruction method and the degree of functional lung impairment posttreatment. The performance of the quantification method was satisfactory when comparing the two treatment schemes. Thus, the 3D reconstruction quantification method may be useful tools for monitoring TB treatment. The association with serum indices are not only inexpensive and sensitive but also may be incorporated into the assessment of patients during TB treatment.

OBJETIVO: Avaliação de condições dos equipamentos e dosimetria em setores de tomografia computadorizada utilizando protocolos de cabeça, abdome e coluna lombar em pacientes adultos (em três equipamentos distintos) e pediátricos com até um ano e meio de vida (em um dos equipamentos avaliados). MATERIAIS E MÉTODOS: Foram estimados o índice de dose em tomografia computadorizada e a dose média em cortes múltiplos, em exames com pacientes adultos, em três distintos equipamentos. Ainda foram estimadas as doses na superfície de entrada e as doses absorvidas em exame de cabeça para pacientes adultos e pediátricos em um dos equipamentos avaliados. RESULTADOS: Foram realizados testes de controle de qualidade, mecânicos, demonstrando que os equipamentos satisfazem as especificações de uso estabelecidas pelas normas vigentes. Os resultados da dosimetria mostraram que valores de dose média em cortes múltiplos excederam em até 109,0% os valores de níveis de referência, apresentando consideráveis variações entre os equipamentos avaliados neste estudo. As doses absorvidas obtidas com protocolos pediátricos são inferiores aos de pacientes adultos, apresentando redução de até 51,0% na tireoide. CONCLUSÃO: Neste estudo foram avaliadas as condições de operação de três equipamentos tomográficos, estabelecendo quais parâmetros devem ser trabalhados para a implantação de um programa de controle de qualidade nas instituições onde esta pesquisa foi desenvolvida.

OBJECTIVE: Evaluation of equipment conditions and dosimetry in computed tomography services utilizing protocols for head, abdomen, and lumbar spine in adult patients (in three different units) and pediatric patients up to 18 months of age (in one of the units evaluated). MATERIALS AND METHODS: Computed tomography dose index and multiple-scan average dose were estimated in studies of adult patients with three different units. Additionally, entrance surface doses as well as absorbed dose were estimated in head studies for both adult and pediatric patients in a single computed tomography unit. RESULTS: Mechanical quality control tests were performed, demonstrating that computed tomography units comply with the equipment-use specifications established by the current standards. Dosimetry results have demonstrated that the multiple-scan average dose values were in excess of up to 109.0% the reference levels, presenting considerable variation amongst the computed tomography units evaluated in the present study. Absorbed doses obtained with pediatric protocols are lower than those with adult patients, presenting a reduction of up to 51.0% in the thyroid gland. CONCLUSION: The present study has analyzed the operational conditions of three computed tomography units, establishing which parameters should be set for the deployment of a quality control program in the institutions where this study was developed.

OBJETIVO: Este trabalho tem como objetivo a otimização de imagens mamográficas, com consideráveis reduções de doses. MATERIAIS E MÉTODOS: Neste estudo o feixe de raios-X foi calibrado para cada tensão (kVp), de modo a determinar a melhor combinação de kVp e mAs que irá proporcionar uma densidade ótica (DO) em torno de 1.0 acima da base mais véu do filme utilizado. RESULTADOS: Serão discutidas questões sobre os métodos empregados para a seleção de parâmetros de exposição do feixe de raios-X, seleção da melhor imagem utilizando o método de avaliação gradativa visual, comparações entre as doses e carga do tubo (kVp × mAs) proporcionadas pelas técnicas determinadas neste estudo e pelas utilizadas na rotina clínica do Serviço de Diagnóstico por Imagem do Hospital das Clínicas da Faculdade de Medicina de Botucatu. Neste estudo foram obtidas imagens radiográficas de mama de excelente qualidade, com redução de dose e carga de tubo, respectivamente, de 36,8% e 46,2%, quando comparadas com a técnica utilizada pela rotina clínica da instituição. CONCLUSÃO: Esta pesquisa vem contribuir com a otimização da relação risco-benefício para o paciente e custo-benefício para a instituição.

OBJECTIVE: The aim of this study is the optimization of mammographic images with a considerable radiation dose reduction. MATERIALS AND METHODS: In the present study the X-ray beam was calibrated for each tension (kVp), aiming at determining the best combination between kVp and mAs, resulting in optical densities of about 1.0 above the base-plus-fog density. RESULTS: This study will bring into question the methods for X-ray beam calibration, the choice of the best image by means of visual grading analysis, comparisons between doses and tube load (kVp × mAs) delivered by the techniques described in this study and by those adopted in the clinical routine at Service of Diagnostic Imaging of Faculdade de Medicina de Botucatu Clinics Hospital, Botucatu, SP, Brazil. Excellent breast radiographic images have been obtained with doses and tube loads reduction of respectively 36.8% and 46.2% in comparison to those employed in our institutions' clinical routine. CONCLUSION: This study is a contribution to the optimization of the risk-benefit ratio for patients and cost-benefit ratio for the institution.