Transferring care to enhance access to early-phase cancer clinical trials: Protocol to evaluate a novel program.

Involving diverse populations in early-phase (phase I and II) cancer clinical trials is critical to informed therapeutic development. However, given the growing costs and complexities of early-phase trials, trial activation and enrollment barriers may be greatest for these studies at healthcare facilities that provide care to the most diverse patient groups, including those in historically underserved communities (e.g., safety-net healthcare systems). To promote diverse and equitable access to early-phase cancer clinical trials, we are implementing a novel program for the transfer of care to enhance access to early-phase cancer clinical trials. We will then perform a mixed-methods study to determine perceptions and impact of the program. Specifically, we will screen, recruit, and enroll diverse patients from an urban, integrated safety-net healthcare system to open and active early-phase clinical trials being conducted in a university-based cancer center. To evaluate this novel program, we will: (1) determine program impact and efficiency; and (2) determine stakeholder experience with and perceptions of the program. To achieve these goals, we will conduct preliminary cost analyses of the program. We will also conduct surveys and interviews with patients and caregivers to elucidate program impact, challenges, and areas for improvement. We hypothesize that broadening access to early-phase cancer trials conducted at experienced centers may improve equity and diversity. In turn, such efforts may enhance the efficiency and generalizability of cancer clinical research.

Robust cardiac segmentation corrected with heuristics.

Cardiovascular diseases related to the right side of the heart, such as Pulmonary Hypertension, are some of the leading causes of death among the Mexican (and worldwide) population. To avoid invasive techniques such as catheterizing the heart, improving the segmenting performance of medical echocardiographic systems can be an option to early detect diseases related to the right-side of the heart. While current medical imaging systems perform well segmenting automatically the left side of the heart, they typically struggle segmenting the right-side cavities. This paper presents a robust cardiac segmentation algorithm based on the popular U-NET architecture capable of accurately segmenting the four cavities with a reduced training dataset. Moreover, we propose two additional steps to improve the quality of the results in our machine learning model, 1) a segmentation algorithm capable of accurately detecting cone shapes (as it has been trained and refined with multiple data sources) and 2) a post-processing step which refines the shape and contours of the segmentation based on heuristics provided by the clinicians. Our results demonstrate that the proposed techniques achieve segmentation accuracy comparable to state-of-the-art methods in datasets commonly used for this practice, as well as in datasets compiled by our medical team. Furthermore, we tested the validity of the post-processing correction step within the same sequence of images and demonstrated its consistency with manual segmentations performed by clinicians.

Inter- and Intra-Operator Variability of Regularized Backscatter Quantitative Ultrasound for the Characterization of Breast Masses.

OBJECTIVES: Here we report on the intra- and inter-operator variability of the backscatter coefficient (BSC) estimated with a new low-variance quantitative ultrasound (QUS) approach applied to breast lesions in vivo. METHODS: Radiofrequency (RF) echo signals were acquired from 29 BIRADS 4 and 5 breast lesions in 2 sequential cohorts following 2 imaging protocols: cohort 1) radial and antiradial views, and cohort 2) short- and long-axis views. Protocol 2 was implemented after retraining and discussion on how to improve reproducibility. Each patient was scanned by at least 2 of 3 radiologists; each performed 3 acquisitions with transducer and patient repositioning in between acquisitions. BSC was estimated using a low-variance QUS approach based on regularization. Intra- and inter-operator variability of the intra-lesion median BSC was evaluated with a multifactorial ANOVA test (P-values) and the intraclass correlation coefficient (ICC). RESULTS: Inter-operator variability was only significant in the first protocol (P < .007); ICCinter = .77 (95% CI .71-.82), indicating good inter-operator agreement. In the second protocol, the inter-operator variability was not significant (P > .05) and agreement was excellent (ICCinter = .92 [.89-.94]). In both protocols, the intra-operator variability was not significant. CONCLUSIONS: Our findings demonstrate the need for standardizing image acquisition protocols for backscatter-based QUS to reduce inter-operator variability and ensure its successful translation to the characterization of suspicious breast masses.

A U-Net with Statistical Shape Restrictions Applied to the Segmentation of the Left Ventricle in Echocardiographic Images / U-Net con Restricciones Estadísticas de Forma, Aplicada a la Segmentación del Ventrículo Izquierdo en Imágenes de Ecocardiograma

Abstract This paper aims to introduce an innovative approach to semantic segmentation by leveraging a convolutional neural network (CNN) for predicting the shape and pose parameters of the left ventricle (LV). Our approach involves a modified U-Net architecture with a regression layer as the final stage, as opposed to the traditional classification layer. This modification allows us to predict all the shape and pose parameters of a statistical shape model, including rotation, translation, scale, and deformation. The adapted U-Net is trained using data from a point distribution model (PDM) of the LV. The experimental results demonstrate a mean Dice coefficient of 0.82 on good quality images, and 0.66 including mean and low-quality images. Our approach successfully overcomes a common issue encountered in CNN-based semantic segmentation. Unlike the inaccurate pixel classification that often leads to unwanted blobs, our CNN generates statistically valid shapes. These shapes hold significant potential in initializing other methods, such as active shape models (ASMs). Our novel CNN-based approach provides a novel solution for semantic segmentation, offering shapes and pose parameters that can enhance the accuracy and reliability of subsequent medical image analysis methods.

Resumen Este artículo tiene como objetivo introducir un enfoque innovador para la segmentación semántica utilizando una red neuronal convolucional (CNN) para predecir los parámetros de forma y posición del ventrículo izquierdo (VI). Nuestro enfoque implica una arquitectura U-Net modificada con una capa de regresión como etapa final, en contraposición a la capa de clasificación tradicional. Esta modificación nos permite predecir todos los parámetros de un modelo estadístico de formas que incluyen rotación, traslación, escala y deformación. La red convolucional se entrena utilizando datos de un modelo de distribución de puntos (PDM) del VI. Los resultados experimentales muestran un coeficiente Dice promedio de 0.82 para imágenes de buena calidad y de 0.66 cuando se incluyen imágenes de calidad media y baja. Nuestro enfoque supera con éxito un problema común en la segmentación semántica basada en CNNs. A diferencia de la clasificación inexacta de píxeles que a menudo conduce a elementos no deseados (blobs), nuestra CNN genera formas estadísticamente válidas. Estas formas tienen un gran potencial para inicializar otros métodos, como los modelos de forma activa (ASMs). En resumen, nuestro enfoque basado en CNN proporciona una solución innovadora para la segmentación semántica, ofreciendo formas y parámetros de posición que pueden mejorar la precisión y confiabilidad de otros métodos de análisis del VI.

A freehand ultrasound framework for spine assessment in 3D: a preliminary study.

X-ray imaging is currently the gold standard for the assessment of spinal deformities. The purpose of this study is to evaluate a freehand 3D ultrasound system for volumetric reconstruction of the spine. A setup consisting of an ultrasound scanner with a linear transducer, an electromagnetic measuring system and a workstation was used. We conducted 64 acquisitions of US images of 8 adults in a natural standing position, and we tested three setups: 1) Subjects are constrained to be close to a wall, 2) Subjects are unconstrained, and 3) Subjects are constrained to performing fast and slow acquisitions. The spinous processes were manually selected from the volume reconstruction from tracked ultrasound images to generate a 3D point-based model depicting the centerline of the spine. The results suggested that a freehand 3D ultrasound system can be suitable for representing the spine. Volumetric reconstructions can be computed and landmarking can be performed to model the surface of the spine in the 3D space. These reconstructions promise to generate computer-based descriptors to analyze the shape of the spine in the 3D space.Clinical Relevance- We provide clinicians with a protocol that could be integrated in clinical setups for the assessment and monitoring of AIS, based on US image acquisitions, which constitutes a radiation-free technology.

Meglumina en series terapéuticas de 10 días en niños con leishmaniosis tegumentaria americana / Meglumine therapeutic series of 10 days in children with american tegumentary leishmaniasis

La cátedra de Medicina Tropical de la Universidad Central de Venezuela viene empleando el antimoniato de meglumina en series terapéuticas de 10 días en el tratamiento de leishmaniosis tegumentaria americana, la cual continúa como problema de salud del medio rural venezolano. Se evalúa una experiencia con una dosis de 70 mg/kg/día de meglumina en niños con la enfermendad. A los pacientes con presunción diagnóstica de leishmaniosis tegumentaria americana (clínica y antecedentes epidemiológicos) se les efectuó la prueba de leishmania, la demostración de anticuerpos flurescentes antileishmania y la visualización de amastigotes en frotis teñidos con Giemsa. Los casos identificados ingresaron al Hospital Universitario (Pediatría médica infecciosa), recibieron 70 mg/kg/día de antimoniato de meglumina en series terapéuticas de 10 días con reposo intercalados por el mismo número de días. Se incluyeron 33 niños con la enfermedad, 21 de género femenino (64%) con promedio de edad 7,12 años y predominio de escolar (70%). Del Estado Miranda procedía el 85%, una sola úlcera la tenía el 88%, localizada en miembros inferiores (49%). La Leishmanina y los anticuerpos fluorescentes antileishmania fueron positivos en todos los pacientes y el frotis para amastigotes en 45%. Dos series de antimoniato de meglumina las recibió 91% de los pacientes; una de 10 días 6%. Egresaron con cicatrizaciones de sus procesos ulcerosos y fueron evaluados durante seis meses en la consulta de endemias rurales y no se evidenciaron recaídas. La variedad cutánea localizada de la enfermedad fue la única identificada, el Estado Miranda continúa aportando la mayoría de los pacientes atendidos en medicina tropical. El antimoniato de meglumina en leishmaniosis tegumentaria americana a la dosis de 70 mg/kg/día en series terapéuticas fue tan eficaz como la anterior de 100 mg/kg/día que dejó de administrarse hace ocho años.

The Tropical Medicine Department of the Universidad Central de Venezuela employs the meglumine pentavalent antimonial in series of 10 days of treatment for American Tegumentary Leishmaniosis, which continues being a health problem in the Venezuelan rural areas. We are reporting a clinical experience of treatment in children at a dose of 70 mg/kg/day. Patients with diagnostic suspición of American Tegumentary Leishmaniosis (clinical and epidemiologic antecedents) who attended the Rural Endemics Clinic at the Instituto de Medicina Tropical of the Universidad Central de Venezuela and to the Medical Infectious Pediatrics Service at the Hospital Universitario de Caracas (HUC), were tested for leishmanine, fluorescent antileishmania antibodies and for the presence of amastigotes of the parasite in smear for apposition from the ulcer that were treated by the Giemsa method. Patients hospitalized at the Medical Infectious Pediatric Service (Hospital Universitario de Caracas) received 70 mg/kg/day of meglumine pentavalent antimonial during 10 days, a rest period of 10 days without treatment and, if 20 days after ulcers were unhealed, was administred a new 10 days meglumine pentavalent antimonial series. We included 33 children with the disease with a mean age of 7,12 years, 70% in school age and 30% preschool children, and 21 (64%) were girls. The 85% of patients came from Miranda`s state, 88% had only ulcer and in 49% of them the lesions where localized in the legs. The apposition smear showed Leishmania amastigotes in 45% od cases. One series of treatment was given to 91% of cases, two children received two series and one three. At discharge from the hospital all ulcers were healed and follow-up control for a 6 months period showed no relapses. The cutaneous localized from was the clinical form of presentation in the children studied. The great majority of patients that assits to the Tropical Medicine Institute come from the Miranda`s state area...