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Advanced breast cancer remains a significant oncological challenge, requiring new approaches to improve clinical outcomes. This study investigated an innovative theranostic agent using the MCM-41-NH2-DTPA-Gd3⁺-MIH nanomaterial, which combined MRI imaging for detection and a novel chemotherapy agent (MIH 2.4Bl) for treatment. The nanomaterial was based on the mesoporous silica type, MCM-41, and was optimized for drug delivery via functionalization with amine groups and conjugation with DTPA and complexation with Gd3+. MRI sensitivity was enhanced by using gadolinium-based contrast agents, which are crucial in identifying early neoplastic lesions. MIH 2.4Bl, with its unique mesoionic structure, allows effective interactions with biomolecules that facilitate its intracellular antitumoral activity. Physicochemical characterization confirmed the nanomaterial synthesis and effective drug incorporation, with 15% of MIH 2.4Bl being adsorbed. Drug release assays indicated that approximately 50% was released within 8 h. MRI phantom studies demonstrated the superior imaging capability of the nanomaterial, with a relaxivity significantly higher than that of the commercial agent Magnevist. In vitro cellular cytotoxicity assays, the effectiveness of the nanomaterial in killing MDA-MB-231 breast cancer cells was demonstrated at an EC50 concentration of 12.6 mg/mL compared to an EC50 concentration of 68.9 mg/mL in normal human mammary epithelial cells (HMECs). In vivo, MRI evaluation in a 4T1 syngeneic mouse model confirmed its efficacy as a contrast agent. This study highlighted the theranostic capabilities of MCM-41-NH2-DTPA-Gd3⁺-MIH and its potential to enhance breast cancer management.

Asunto(s)

Neoplasias de la Mama , Imagen por Resonancia Magnética , Nanopartículas , Dióxido de Silicio , Nanomedicina Teranóstica , Dióxido de Silicio/química , Animales , Humanos , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/patología , Femenino , Nanomedicina Teranóstica/métodos , Imagen por Resonancia Magnética/métodos , Ratones , Línea Celular Tumoral , Nanopartículas/química , Antineoplásicos/farmacología , Antineoplásicos/química , Antineoplásicos/uso terapéutico , Medios de Contraste/química , Gadolinio/química , Porosidad , Ensayos Antitumor por Modelo de Xenoinjerto

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Background: Vascular Doppler ultrasound (DUS) has evolved over recent years because of improvements in the technology involved in the acquisition and processing of sound and image data. The method is an excellent option for use in diagnosis of peripheral arterial disease considering its availability, low cost, and absence of harmful effects. The breakdown of logistics supply chains caused by the COVID-19 pandemic caused worldwide shortages of iodinated contrast, highlighting the need to validate alternative diagnostic methods. Objective: To use DUS for decision-making when choosing between by-pass and endovascular surgery for femoropopliteal arterial disease and compare the results to those of iodinated contrast exams. Methods: We compared DUS with examinations using contrast for identification of stenoses/occlusions and indication of surgical treatment (by-pass vs. endovascular). In the first phase of the study the results were merely compared, DUS vs. angiotomography. Then, in the second phase, the vascular ultrasound results were used for screening between by-pass and endovascular treatment, comparing DUS with angiotomography in cases scheduled for by-pass and with arteriography in endovascular patients. Results: In phase 1, the sensitivity of DUS compared to CT angiography was 100% for the SFA territory. When considering solely the choice of bypass vs. endovascular treatment, the results showed 100% agreement for phase 1 and 94% for phase 2. Conclusion: Notwithstanding the sample size, the study fulfilled its objective of demonstrating the reliability of DUS for indicating the treatment choice between by-pass and endovascular surgery.

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In the quest to uncover biological cues that help explain organic changes brought on by an external stimulus, like stress, new technologies have become necessary. The Laser Speckle Contrast Analysis (LASCA) approach is one of these technologies that may be used to analyze biological data, including respiratory rate (RR) intervals, and then use the results to determine heart rate variability (HRV Thus, to evaluate the stress brought on by physical activity, this study used the LASCA approach. A stress induction procedure involving physical exertion was employed, and the results were compared to other established techniques (cortisol analysis and ECG signal) to verify the LASCA methodology as a tool for measuring HRV and stress. The study sample comprised 27 willing participants. The technique involving LASCA allowed for the non-invasive (non-contact) acquisition of HRV and the study of stress. Furthermore, it made it possible to gather pertinent data, such as recognizing modifications to the thermoregulation, peripheral vasomotor tonus, and renin-angiotensin-aldosterone systems that were brought on by elevated stress and, as a result, variations in HRV readings.

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Frecuencia Cardíaca , Estrés Fisiológico , Humanos , Frecuencia Cardíaca/fisiología , Proyectos Piloto , Masculino , Adulto , Femenino , Estrés Fisiológico/fisiología , Adulto Joven , Electrocardiografía/métodos , Rayos Láser , Hidrocortisona , Frecuencia Respiratoria/fisiología

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The anatomical variations of the maxillary septum and the septal bullae can generate challenges during the interpretation of radiographs of the horses' heads and make it difficult to accurately identify the sites affected in sinus disorders. The description of the radiographic appearance of these structures is currently scarce in the scientific literature. This work aims to describe the anatomical and radiographic characteristics of the maxillary septum and maxillary septal bullae in horses. Six chemically preserved equine cadaver heads were used which, after being submitted to the maxillary osseous flap, the maxillary septum and its respective bullae were identified. Radiographic examinations before and after contrast impregnation on these structures were performed. The positioning of the maxillary septum varied between the anatomical specimens and between the sides of the same specimen. The 30° oblique dorsoventral lateral and lateral projections allowed the identification of the maxillary septum and septal bullae. However, the bullae remained superimposed on the dental arches in the dorsoventral projections with the mandible in a neutral position or with the mandible displaced. The oblique offset radiographic positioning was suggested and proved effective for the examination of the maxillary septal bullae, where the mandible was displaced to the side of the bullae to be examined, and the radiographic beam inclined in the same direction. The maxillary septum and its bullae could be properly identified in a macroscopic way after the osseous flap and the contrasted radiographic examination allowed its adequate interpretation. Variations in size and position are considered normal for the equine species.

Asunto(s)

Cadáver , Caballos/anatomía & histología , Animales , Tabique Nasal/diagnóstico por imagen , Maxilar/diagnóstico por imagen , Radiografía/veterinaria , Masculino , Enfermedades de los Caballos/diagnóstico por imagen

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BACKGROUND: Typical propagation-based X-ray phase contrast imaging (PB-PCI) experiments using polyenergetic sources are tested in very ideal conditions: low-energy spectrum (mainly characteristic X-rays), small thickness and homogeneous materials considered weakly absorbing objects, large object-to-detector distance, long exposure times and non-clinical detector. OBJECTIVE: Explore PB-PCI features using boundary conditions imposed by a low power polychromatic X-ray source (X-ray spectrum without characteristic X-rays), thick and heterogenous materials and a small area imaging detector with high low-detection radiation threshold, elements commonly found in a clinical scenario. METHODS: A PB-PCI setup implemented using a microfocus X-ray source and a dental imaging detector was characterized in terms of different spectra and geometric parameters on the acquired images. Test phantoms containing fibers and homogeneous materials with close attenuation characteristics and animal bone and mixed soft tissues (bio-sample models) were analyzed. Contrast to Noise Ratio (CNR), system spatial resolution and Kerma values were obtained for all images. RESULTS: Phase contrast images showed CNR up to 15% higher than conventional contact images. Moreover, it is better seen when large magnifications (>3) and object-to-detector distances (>13 cm) were used. The influence of the spectrum was not appreciable due to the low efficiency of the detector (thin scintillator screen) at high energies. CONCLUSIONS: Despite the clinical boundary condition used in this work, regarding the X-ray spectrum, thick samples, and detection system, it was possible to acquire phase contrast images of biological samples.

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Fantasmas de Imagen , Animales , Rayos X , Humanos

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ABSTRACT Introduction: Contrast-associated acute kidney injury (CA-AKI) is a deterioration of kidney function that occurs after the administration of a iodinated contrast medium (ICM). Most studies that defined this phenomenon used older ICMs that were more prone of causing CA-AKI. In the past decade, several articles questioned the true incidence of CA-AKI. However, there is still a paucity of a data about the safety of newer ICM. Objective: To assess the incidence of CA-AKI in hospitalized patients that were exposed to computed tomography (CT) with and without ICM. Methods: Prospective cohort study with 1003 patients who underwent CT in a tertiary hospital from December 2020 through March 2021. All inpatients aged > 18 years who had a CT scan during this period were screened for the study. CA-AKI was defined as a relative increase of serum creatinine of ≥ 50% from baseline or an absolute increase of ≥ 0.3 mg/dL within 18 to 48 hours after the CT. Chi-squared test, Kruskal-Wallis test, and linear regression model with restricted cubic splines were used for statistical analyses. Results: The incidence of CA-AKI was 10.1% in the ICM-exposed group and 12.4% in the control group when using the absolute increase criterion. The creatinine variation from baseline was not significantly different between groups. After adjusting for baseline factors, contrast use did not correlate with worse renal function. Conclusion: The rate of CA-AKI is very low, if present at all, with newer ICMs, and excessive caution regarding contrast use is probably unwarranted.

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RESUMO Introdução: Lesão renal aguda associada ao contraste (LRA-AC) é uma deterioração da função renal que ocorre após a administração de meio de contraste iodado (MCI). A maioria dos estudos que definiram esse fenômeno utilizaram MCI mais antigos, mais propensos a causar LRA-AC. Na última década, diversos artigos questionaram a verdadeira incidência de LRA-AC. Entretanto, ainda há escassez de dados sobre a segurança dos MCI mais novos. Objetivo: Avaliar a incidência de LRA-AC em pacientes hospitalizados expostos à tomografia computadorizada (TC) com e sem MCI. Métodos: Estudo de coorte prospectivo com 1.003 pacientes submetidos a TC em hospital terciário, de dezembro/2020 a março/2021. Todos os pacientes internados com idade ≥ 18 anos que realizaram TC nesse período foram selecionados. A LRA-AC foi definida como aumento relativo de creatinina sérica de ≥ 50% em relação ao valor basal ou aumento absoluto de ≥ 0,3 mg/dL dentro de 18 a 48 horas após a TC. Utilizamos o teste qui-quadrado, teste de Kruskal-Wallis e modelo de regressão linear com splines cúbicos restritos para análises estatísticas. Resultados: A incidência de LRA-AC foi 10,1% no grupo exposto ao MCI e 12,4% no grupo controle ao usar o critério de aumento absoluto. A variação da creatinina em relação ao valor basal não foi significativamente diferente entre os grupos. Após ajuste para fatores basais, o uso de contraste não se correlacionou com pior função renal. Conclusão: A taxa de LRA-AC é muito baixa, caso exista, com MCIs mais novos, e a cautela excessiva quanto ao uso de contraste provavelmente não se justifica.

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Objective The objective of the study was to evaluate the use of the hepatospecific contrast agent, gadoxetic acid, for MRI in patients at a high-complexity hospital in Medellin, Colombia, from 2016 to 2022. Materials and methods This was an observational, descriptive, and retrospective cross-sectional study involving patients who had undergone MRI with gadoxetic acid from February 2016 to January 2022. The MRI studies were interpreted by two radiologists specializing in body imaging, each with at least 10 years of experience. The medical records of the identified patients were reviewed. Quantitative variables were presented using either means and standard deviations or medians and interquartile ranges, depending on the distribution of the variables. Qualitative variables were represented through absolute and relative frequencies. Results A total of 100 pharmacy records were collected, leading to a final sample of 75 patients aged between three and 91 years. The primary reason for imaging was to assess focal liver lesions in 58 patients (77.3%), with bile duct injury being the second most common indication in 16 patients (21.3%). A diagnostic alteration was noted in 69.3% of cases (52 patients). Among the 58 focal liver lesions analyzed using a hepatospecific agent, 31 cases (53.4%) were diagnosed as focal nodular hyperplasia. Conclusion Our study reinforces the clinical value of gadoxetic acid-enhanced MRI in refining diagnostic assessments, particularly in cases involving bile duct and focal hepatic lesions.

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In the animal kingdom, threat information is perceived mainly through vision. The subcortical visual pathway plays a critical role in the rapid processing of visual information-induced fear, and triggers a response. Looming-evoked behavior in rodents, mimicking response to aerial predators, allowed identify the neural circuitry underlying instinctive defensive behaviors; however, the influence of disk/background contrast on the looming-induced behavioral response has not been examined, either in rats or mice. We studied the influence of the dark disk/gray background contrast in the type of rat and mouse defensive behavior in the looming arena, and we showed that rat and mouse response as a function of disk/background contrast adjusted to a sigmoid-like relationship. Both sex and age biased the contrast-dependent response, which was dampened in rats submitted to retinal unilateral or bilateral ischemia. Moreover, using genetically manipulated mice, we showed that the three type of photoresponsive retinal cells (i.e., cones, rods, and intrinsically photoresponsive retinal ganglion cells (ipRGCs)), participate in the contrast-dependent response, following this hierarchy: cones > > rods > > > ipRGCs. The cone and rod involvement was confirmed using a mouse model of unilateral non-exudative age-related macular degeneration, which only damages canonical photoreceptors and significantly decreased the contrast sensitivity in the looming arena.

Asunto(s)

Estimulación Luminosa , Células Ganglionares de la Retina , Animales , Ratas , Ratones , Masculino , Células Ganglionares de la Retina/fisiología , Femenino , Sensibilidad de Contraste/fisiología , Conducta Animal/fisiología , Células Fotorreceptoras Retinianas Conos/fisiología , Ratones Endogámicos C57BL , Percepción Visual/fisiología , Miedo/fisiología , Retina/fisiología , Vías Visuales/fisiología

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Successive Negative Contrast (SNC) occurs when there is a reduction in the quantity or quality of a reward that is expected according to the presence of contextual cues. This induces an emotional response of frustration that is similar to stress. While this phenomenon has been observed in several mammal species, findings in domestic dogs have been inconsistent, although this issue has strong relevance in dog training. The aim of this study was to assess the effects of Successive Negative Contrast in two responses that had already been studied in this species, but with an increase in the methodological rigor and variations in the experimental conditions to examine the generalizability of the phenomenon. To this end, experimental dogs experienced a pre-shift phase in which they received a high-value reward (liver), followed by a post-shift phase in which they obtained a low-value reward (dry dog food), and then a re-shift phase in which the high-value reward was available again. Control dogs received dry food in all phases. The results show a contrast effect on the behavior of following human pointing to obtain food (Study 1). On the contrary, there were no differences in problem solving behavior after the de- and re-evaluation of the reward during a non-social task (Study 2). The results support that Successive Negative Contrast is not a consistent phenomenon in pet dogs. It is possible that certain characteristics of dogs such as the great availability of high-value rewards in their daily lives could attenuate the effects of a reduction in incentive value.

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Resumen La mamografía contrastada (CEDM, contrast-enhanced digital mammography) es una herramienta nueva que ha ido implementándose de forma creciente. Aparece como alternativa a la resonancia magnética (RM), y al igual que esta, tiene como principio el uso de contraste endovenoso para explorar la angiogénesis tumoral. Combina la imagen de mamografía convencional (Mx) con la técnica de sustracción con energía dual poscontraste, lo que resulta en un incremento en la detección de cáncer de mama, en un tiempo corto de estudio y a un bajo costo. Es un método prometedor en casos seleccionados y de fácil lectura, siendo útil principalmente en pacientes con diagnóstico de cáncer de mama para detectar lesiones adicionales y determinar el tamaño tumoral, ayudando en la planificación quirúrgica, así como también en la evaluación de la respuesta a la neoadyuvancia. También en el seguimiento de pacientes operadas, para caracterizar lesiones dudosas en Mx y ecografía, o como alternativa ante contraindicación de la RM. El objetivo de este trabajo es valorar la utilidad de la mamografía contrastada en la práctica diaria y determinar sus principales indicaciones. Repasamos con casos propios las utilidades y características del método.

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Abstract Contrast-enhanced digital mammography (CEDM) is an emerging tool that has been increasingly implemented. It appears as an alternative to magnetic resonance imaging (MRI), using intravenous contrast to explore tumor angiogenesis. It combines conventional mammography (Mx) with post-contrast dual energy subtraction technique, resulting in increased detection of breast cancer, in a short study time and at a low cost. It is a promising method in selected cases and easy to read, being useful mainly in patients with breast cancer to detect additional lesions and determine the tumor size, that helps surgical planning, as well as in the evaluation of post-neoadjuvant chemotherapy response in the follow-up of patients treated with surgery, to address inconclusive findings in screening mammogram, or as an alternative when MRI is contraindicated. The purpose of this article is to assess the usefulness of contrasted mammography in daily practice and to determine its main indications. We review with our own cases the applications and characteristics of this method.

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The aim of this literature review was to present the novel imaging modalities elastography and contrast-enhanced ultrasonography. We provided an overview of the concepts and applications of each technique for the investigation of neoplastic and metastatic tumors in dogs and cats. Studies on elastography are based on the elasticity and deformation of the evaluated tissue. The information obtained from the different types of elastography can aid in the detection and differentiation of malignant and benign structures. Descriptions of elastography studies in several organs and tissue in veterinary medicine reported that, in general, malignant tumors tend to be more rigid and, therefore, less deformable than benign lesions or in comparison to the healthy parenchyma. Contrast-enhanced ultrasonography is based on the intravenous injection of contrast media constituted by microbubbles. This imaging modality can be performed in nonsedated animals and provides information on the tissue perfusion, allowing the investigation of macro- and micro-circulation. Studies on different organs and tissues were performed in dogs and cats and revealed a tendency of malignant tumors to present faster transit of the contrast media (time to wash-in, peak and wash-out). These advanced techniques can be associated with other imaging modalities, aiding important information to the well-established exams of B-mode and Doppler ultrasonography. They can be used as screening tests, potentially representing an alternative to the invasive sampling methods required for cytological and histopathological analysis.

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Veterinary care for rabbits has been growing, and, consequently, the anesthetic and analgesic management of this species must be improved. The aim of the present study was to evaluate the technique of localization of the epidural space with the aid of a peripheral nerve stimulator and epidurographic, comparing two techniques for determining the infused volume in rabbits (Oryctolagus Cuniculus). In a prospective, randomized blinded study, six healthy New Zealand rabbits, adults, and weighing from 2.2 kg to 3.8 kg received two treatments, at 1 week intervals: 0.33 mL/kg (treatment I) or 0.05 mL per centimeter of the spine (treatment II) of ioexol epidurally. In both treatments, a peripheral nerve stimulator (2 Hz, 0.25 mA and 0.1 milliseconds) was used to determine the location of the epidural space. Latero-lateral and ventro-dorsal radiographs were taken after five (T5) and twenty-five minutes (T25) of iohexol administration. The epidural space was correctly accessed in 92% of attempts. Treatment I received a smaller volume of contrast than treatment II, 1.0 ± 0.2 mL versus 2.1 ± 0.1 mL (mean ± standard deviation), respectively (p = 0.007). At T5, the cranial progression of the contrast varied between L4 and L5 in treatment I, and L5 and T10 in treatment II. At T25, no contrast was observed in any rabbit. In conclusion, peripheral nerve stimulator aided in accessing the lumbosacral epidural space, and the administration of 0.05 mL per centimeter of the spine resulted in greater cranial progression of contrast.

Asunto(s)

Espacio Epidural , Yohexol , Conejos , Animales , Inyecciones Epidurales/veterinaria , Inyecciones Epidurales/métodos , Estudios Prospectivos , Nervios Periféricos

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Electrical bioimpedance is a non-invasive and radiation-free technique that was proposed to be used in different clinical areas, however, its practical use is limited due to its low capacity to discriminate between tissues. In order to overcome this limitation, our research group proposes to incorporate the contrast media into the electrical bioimpedance procedure. The main objective of the present study was to assess the crystalloid solutions as a possible contrast media to discriminate between different tissue types in the bioimpedance technique. Two medical-grade crystalloid solutions (Hartmann and NaCl 0.9%) were injected into three biological ex vivo models: kidney, liver, and brain. BIOPAC system was used to acquire bioimpedance data before and after the injections. The data was adjusted to the Debye electrical model. The analysis of measured values showed substantial bioimpedance disparities in tissues subjected to isotonic solutions. The NaCl solution exhibited more pronounced changes in electrical parameters compared to the Hartmann solution. Similarly, NaCl solution displayed superior discriminatory capabilities among tissues, with variations of 465%, 157%, and 206%. Distinct spectral modifications were identified, with tissues demonstrating unique responses at each frequency of analysis relative to untreated tissue. Variations in bandwidth alterations were discernible among tissues, providing clear distinctions. In conclusion, the research showed that the crystalloid solution exhibited greater sensitivity and superior tissue contrast at specific frequencies. This study's findings underscore the feasibility of implementing crystalloid solutions to enhance tissue discrimination, similar to the effects of contrast agents.

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Técnicas Biosensibles , Cloruro de Sodio , Soluciones Cristaloides , Medios de Contraste , Impedancia Eléctrica

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Objetivo: En el abordaje y diagnóstico de la urolitiasis, la tomografía computarizada (TC) con enfoque en el tracto urinario es el método de referencia. Sin embargo la ultrasonografía renal podría ser más costo-efectiva y rápida en algunos entornos. La ultrasonografía renal se ha considerado como una alternativa en los protocolos de emergencia de algunas instituciones. El objetivo es evaluar la concordancia diagnóstica entre la ecografía y la TC sin contraste en un centro de cuarto nivel. Método: Se desarrolló una base de datos con una muestra de todos los pacientes que fueron llevados a TC sin contraste y ecografía renal por un cuadro clínico sugestivo de urolitiasis. Se seleccionaron todos los pacientes entre enero de 2011 y

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Humanos , Ultrasonido , Sistema Urinario , Pruebas Diagnósticas de Rutina , Urolitiasis , Diagnóstico , Tomografía , Organizaciones , Guías como Asunto

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SUMMARY OBJECTIVE: Nowadays, the frequency of complications is also increasing following the increasing frequency of coronary angiography and percutaneous coronary intervention. Contrast-induced nephropathy is one of the most common of these complications. This study aimed to investigate the relationship between the Osaka prognostic score, which has previously been shown to have prognostic importance in gastrointestinal malignancies, and the development of contrast-induced nephropathy. METHODS: The study retrospectively examined the data of 1,498 patients who underwent coronary angiography and percutaneous coronary intervention due to acute coronary syndrome between 2018 and 2023. Demographic characteristics and laboratory findings were retrospectively collected from patients' charts and electronic medical records. RESULTS: Osaka prognostic score (0.84±0.25 vs. 2.2±0.32, p<0.001) was higher in patients who developed contrast-induced nephropathy. Also, Osaka prognostic score [OR 2.161 95%CI (1.101-4.241), p<0.001] was found to be an independent risk factor along with age, diabetes mellitus, systolic pulmonary artery pressure, hemoglobin, hemoglobin, C-reactive protein, albumin, N-terminal brain natriuretic peptide, and systemic immune-inflammation index. The receiver operating characteristic curve showed that the optimal cutoff value of Osaka prognostic score to predict the development of contrast-induced nephropathy was 1.5, with a sensitivity of 83.4 and a specificity of 65.9% [area under the curve: 0.874 (95%CI: 0.850-0.897, p≤0.001)]. CONCLUSION: Osaka prognostic score may be an easily calculable, user-friendly, and useful parameter to predict the development of contrast-induced nephropathy in patients undergoing percutaneous coronary intervention after acute coronary syndromes.

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Resumo Contexto A ecografia vascular com Doppler (EVD) evoluiu nos últimos anos devido ao aprimoramento da tecnologia de aquisição e processamento da imagem. A disponibilidade do exame, o baixo custo e a ausência de efeitos deletérios de radiação e contraste tornam este método uma excelente opção no diagnóstico da doença arterial periférica. As quebras nas cadeias de suprimentos devido à pandemia de covid-19 levaram a uma escassez global de contraste iodado, reforçando a importância de validar abordagens alternativas. Objetivos Utilizar a EVD na decisão entre cirurgia aberta ou endovascular para doença arterial femoropoplítea e comparar os resultados com exames de contraste iodado. Métodos Comparamos EVD com exames contrastados (angiotomografia e arteriografia) em relação à localização de estenoses/oclusões e indicação do tratamento cirúrgico (by-pass vs. endovascular). Em uma primeira fase, os resultados foram apenas comparados entre EVD e angiotomografia. Numa segunda fase, os resultados da EVD foram usados na triagem entre by-pass vs. endovascular), sendo comparados com angiotomografia nos casos de cirurgia aberta e comparados com a arteriografia nos casos de tratamento endovascular. Resultados A sensibilidade da EVD em comparação com a angiotomografia na fase 1 foi de 100% para o território da artéria femoral superficial. Ao considerar apenas a indicação de by-pass versus endovascular, os resultados mostraram 100% de concordância para a Fase 1 e 94% para a Fase 2. Conclusões Com a ressalva do tamanho amostral, o estudo cumpriu seu objetivo de demonstrar a confiabilidade da EVD na indicação do tratamento cirúrgico entre aberto ou endovascular.

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Abstract Background Vascular Doppler ultrasound (DUS) has evolved over recent years because of improvements in the technology involved in the acquisition and processing of sound and image data. The method is an excellent option for use in diagnosis of peripheral arterial disease considering its availability, low cost, and absence of harmful effects. The breakdown of logistics supply chains caused by the COVID-19 pandemic caused worldwide shortages of iodinated contrast, highlighting the need to validate alternative diagnostic methods. Objective To use DUS for decision-making when choosing between by-pass and endovascular surgery for femoropopliteal arterial disease and compare the results to those of iodinated contrast exams. Methods We compared DUS with examinations using contrast for identification of stenoses/occlusions and indication of surgical treatment (by-pass vs. endovascular). In the first phase of the study the results were merely compared, DUS vs. angiotomography. Then, in the second phase, the vascular ultrasound results were used for screening between by-pass and endovascular treatment, comparing DUS with angiotomography in cases scheduled for by-pass and with arteriography in endovascular patients. Results In phase 1, the sensitivity of DUS compared to CT angiography was 100% for the SFA territory. When considering solely the choice of bypass vs. endovascular treatment, the results showed 100% agreement for phase 1 and 94% for phase 2. Conclusion Notwithstanding the sample size, the study fulfilled its objective of demonstrating the reliability of DUS for indicating the treatment choice between by-pass and endovascular surgery.

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BACKGROUND: X-ray breast imaging modalities are commonly employed for breast cancer detection, from screening programs to diagnosis. Thus, dosimetry studies are important for quality control and risk estimation since ionizing radiation is used. PURPOSE: To perform multiscale dosimetry assessments for different breast imaging modalities and for a variety of breast sizes and compositions. The first part of our study is focused on macroscopic scales (down to millimeters). METHODS: Nine anthropomorphic breast phantoms with a voxel resolution of 0.5 mm were computationally generated using the BreastPhantom software, representing three breast sizes with three distinct values of volume glandular fraction (VGF) for each size. Four breast imaging modalities were studied: digital mammography (DM), contrast-enhanced digital mammography (CEDM), digital breast tomosynthesis (DBT) and dedicated breast computed tomography (BCT). Additionally, the impact of tissue elemental compositions from two databases were compared. Monte Carlo (MC) simulations were performed with the MC-GPU code to obtain the 3D glandular dose distribution (GDD) for each case considered with the mean glandular dose (MGD) fixed at 4 mGy (to facilitate comparisons). RESULTS: The GDD within the breast is more uniform for CEDM and BCT compared to DM and DBT. For large breasts and high VGF, the ratio between the minimum/maximum glandular dose to MGD is 0.12/4.02 for DM and 0.46/1.77 for BCT; the corresponding results for a small breast and low VGF are 0.35/1.98 (DM) and 0.63/1.42 (BCT). The elemental compositions of skin, adipose and glandular tissue have a considerable impact on the MGD, with variations up to 30% compared to the baseline. The inclusion of tissues other than glandular and adipose within the breast has a minor impact on MGD, with differences below 2%. Variations in the final compressed breast thickness alter the shape of the GDD, with a higher compression resulting in a more uniform GDD. CONCLUSIONS: For a constant MGD, the GDD varies with imaging modality and breast compression. Elemental tissue compositions are an important factor for obtaining MGD values, being a source of systematic uncertainties in MC simulations and, consequently, in breast dosimetry.

Asunto(s)

Mamografía , Radiometría , Rayos X , Método de Montecarlo , Radiometría/métodos , Mamografía/métodos , Fantasmas de Imagen , Dosis de Radiación

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Focused ion beam scanning electron microscopy (FIB-SEM) tomography is a serial sectioning technique where an FIB mills off slices from the material sample that is being analysed. After every slicing, an SEM image is taken showing the newly exposed layer of the sample. By combining all slices in a stack, a 3D image of the material is generated. However, specific artefacts caused by the imaging technique distort the images, hampering the morphological analysis of the structure. Typical quality problems in microscopy imaging are noise and lack of contrast or focus. Moreover, specific artefacts are caused by the FIB milling, namely, curtaining and charging artefacts. We propose quality indices for the evaluation of the quality of FIB-SEM data sets. The indices are validated on real and experimental data of different structures and materials.

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Significance: Speckle contrast analysis is the basis of laser speckle imaging (LSI), a simple, inexpensive, noninvasive technique used in various fields of medicine and engineering. A common application of LSI is the measurement of tissue blood flow. Accurate measurement of speckle contrast is essential to correctly measure blood flow. Variables, such as speckle grain size and camera pixel size, affect the speckle pattern and thus the speckle contrast. Aim: We studied the effects of spatial correlation among adjacent camera pixels on the resulting speckle contrast values. Approach: We derived a model that accounts for the potential correlation of intensity values in the common experimental situation where the speckle grain size is larger than the camera pixel size. In vitro phantom experiments were performed to test the model. Results: Our spatial correlation model predicts that speckle contrast first increases, then decreases as the speckle grain size increases relative to the pixel size. This decreasing trend opposes what is observed with a standard speckle contrast model that does not consider spatial correlation. Experimental data are in good agreement with the predictions of our spatial correlation model. Conclusions: We present a spatial correlation model that provides a more accurate measurement of speckle contrast, which should lead to improved accuracy in tissue blood flow measurements. The associated correlation factors only need to be calculated once, and open-source software is provided to assist with the calculation.

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Técnicas de Diagnóstico Cardiovascular , Hemodinámica , Fantasmas de Imagen , Programas Informáticos

RESUMEN

Objectives: Our study aims to demonstrate the detection of invasion by biparametric prostate MRI (bpMRI). Materials and methods: The cases whose histopathological diagnosis was prostate cancer (PCa) and whose mpMRI report was reported as PIRADS 4 and 5 were evaluated retrospectively by two radiologists with different prostate imaging experiences. The images were grouped into two data sets. Dataset-1 was bpMRI, and dataset-2 was mpMRI. Two radiologists first evaluated dataset-1 independently of each other, and 1 month later, dataset-2. They recorded whether there was an invasion and where it was seen in the patients. Then, the results were compared. Results: A total of 75 patients were included in the study. Periprostatic invasion was detected in 33 of the patients. Both the 1st reader and the 2nd reader image detected all the cases with invasion (100%) separately between dataset-1 and set-2. Compatibility for image dataset-1 and dataset-2 between both readers was observed to be excellent. Conclusions: There is no need to use contrast agent to evaluate periprostatic invasion and to have an idea about local staging in PCa patients.

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Objetivo: Nuestro estudio tiene como objetivo demostrar la detección de la invasión por resonancia magnética biparamétrica de próstata (BPMRI). Material y métodos: Los casos cuyo diagnóstico histopatológico fue PCA y cuyo informe MPMRI se informó como Pirads 4 y 5 fueron evaluados retrospectivamente por dos radiólogos con diferentes experiencias de imágenes de próstata. Las imágenes se agruparon en dos conjuntos de datos. DataSet-1 fue BPMRI, DataSet-2 fue MPMRI. Dos radiólogos evaluaron por primera vez el conjunto de datos 1 independientemente el uno del otro, y 1 mes después, el conjunto de datos-2. Registraron si había una invasión y dónde se vio en los pacientes. Luego se compararon los resultados. Resultados: Se incluyeron un total de 75 pacientes en el estudio. La invasión periprostática se detectó en 33 de los pacientes. Tanto el primer lector como la imagen del segundo lector detectaron todos los casos con invasión (100%) por separado entre el conjunto de datos-1 y el set-2. Se observó que la compatibilidad para el conjunto de datos de imágenes-1 y el conjunto de datos entre ambos lectores era excelente. Conclusiones: No es necesario usar el agente de contraste para evaluar la invasión periprostática y tener una idea sobre la puesta en escena local en pacientes con PCA.