Machine learning approach for distinguishing malignant and benign lung nodules utilizing standardized perinodular parenchymal features from CT.

PURPOSE: Computed tomography (CT) is an effective method for detecting and characterizing lung nodules in vivo. With the growing use of chest CT, the detection frequency of lung nodules is increasing. Noninvasive methods to distinguish malignant from benign nodules have the potential to decrease the clinical burden, risk, and cost involved in follow-up procedures on the large number of false-positive lesions detected. This study examined the benefit of including perinodular parenchymal features in machine learning (ML) tools for pulmonary nodule assessment. METHODS: Lung nodule cases with pathology confirmed diagnosis (74 malignant, 289 benign) were used to extract quantitative imaging characteristics from computed tomography scans of the nodule and perinodular parenchyma tissue. A ML tool development pipeline was employed using k-medoids clustering and information theory to determine efficient predictor sets for different amounts of parenchyma inclusion and build an artificial neural network classifier. The resulting ML tool was validated using an independent cohort (50 malignant, 50 benign). RESULTS: The inclusion of parenchymal imaging features improved the performance of the ML tool over exclusively nodular features (P < 0.01). The best performing ML tool included features derived from nodule diameter-based surrounding parenchyma tissue quartile bands. We demonstrate similar high-performance values on the independent validation cohort (AUC-ROC = 0.965). A comparison using the independent validation cohort with the Fleischner pulmonary nodule follow-up guidelines demonstrated a theoretical reduction in recommended follow-up imaging and procedures. CONCLUSIONS: Radiomic features extracted from the parenchyma surrounding lung nodules contain valid signals with spatial relevance for the task of lung cancer risk classification. Through standardization of feature extraction regions from the parenchyma, ML tool validation performance of 100% sensitivity and 96% specificity was achieved.

A Method for Delineation of Bone Surfaces in Photoacoustic Computed Tomography of the Finger.

Photoacoustic (PA) imaging of interphalangeal peripheral joints is of interest in the context of using the synovial membrane as a surrogate marker of rheumatoid arthritis. Previous work has shown that ultrasound (US) produced by absorption of light at the epidermis reflects on the bone surfaces within the finger. When the reflected signals are backprojected in the region of interest, artifacts are produced, confounding interpretation of the images. In this work, we present an approach where the PA signals known to originate from the epidermis are treated as virtual US transmitters, and a separate reconstruction is performed as in US reflection imaging. This allows us to identify the bone surfaces. Furthermore, the identification of the joint space is important as this provides a landmark to localize a region-of-interest in seeking the inflamed synovial membrane. The ability to delineate bone surfaces allows us to identify not only the artifacts but also the interphalangeal joint space without recourse to new US hardware or a new measurement. We test the approach on phantoms and on a healthy human finger.

Fabrication of carbon films with ∼ 500nm holes for cryo-EM with a direct detector device.

Single particle electron cryomicroscopy (cryo-EM) is often performed using EM grids coated with a perforated or holey layer of amorphous carbon. Regular arrays of holes enable efficient cryo-EM data collection and several methods for the production of micropatterned holey-carbon film coated grids have been described. However, a new generation of direct detector device (DDD) electron microscope cameras can benefit from hole diameters that are smaller than currently available. Here we extend a previously proposed method involving soft lithography with a poly(dimethylsiloxane) (PDMS) stamp for the production of holey-carbon film coated EM grids. By incorporating electron-beam (e-beam) lithography and modifying the procedure, we are able to produce low-cost high-quality holey-carbon film coated EM grids with ∼500nm holes spaced 4µm apart centre-to-centre. We demonstrate that these grids can be used for cryo-EM. Furthermore, we show that by applying image shifts to obtain movies of the carbon regions beside the holes after imaging the holes, the contrast transfer function (CTF) parameters needed for calculation of high-resolution cryo-EM maps with a DDD can be obtained efficiently.

Digitalización integral de una organización de servicios sanitarios / Integral digitalization of a health services organization

La digitalización es un proceso iniciado en diversos centros sanitarios, a menudo de manera fragmentada; aún son pocas las organizaciones sanitarias que han conseguido integrar las imágenes diagnósticas en una historia clínica informatizada, suprimir totalmente el papel y difundir telemáticamente dichas imágenes hacia otros centros sanitarios periféricos, como es el caso del Hospital Municipal de Badalona. En este artículo pretendemos divulgar nuestra experiencia en el proceso que nos ha llevado a la digitalización integral de nuestra organización: las dificultades y los beneficios, las ventajas y puntos débiles, con el deseo de facilitar el camino a quienes vayan a emprenderlo (AU)

The authors of this article concisely relate their experience in the process which has been carried out in the integral digitalization of the hospital: The difficulties and the benefits, the advantages and weak points (AU)

High-performance nonscanning Fourier-transform spectrometer that uses a Wollaston prism array.

A high-performance nonscanning Fourier-transform spectrometer is reported that is composed mainly of a Wollaston prism array and a two-dimensional photodetector array. It is a substantial improvement over existing Wollaston prism based nonscanning Fourier-transform spectrometers because it offers finer spectral resolution and smaller size. Such spectrometers will find important applications in remote chemical and biological sensing, environmental monitoring, medical diagnosis, etc. Experimental results are consistent with theoretical analyses.

Proposal for a compputer program for 99m Tc-DTPA alveolar capillary clearance study

Os radioaerossóis e a cintilografia de ventilaçäo tem papeis bem definidos na rotina medica nuclear. Estudos sobre o clearance alveolo-capilar de tecnécio-99m marcando o ácido dietileno triamino penta-acético (99mTc-DPTA) permitem um diagnóstico precoce, ao menos presuntivo, de infecçöes pulmonares oportunistas, com uma sensibilidade maior que a dos estudos convencionais. Nós desenvolvemos um programa no computador acoplado à câmara de cintilaçäo para processar as imagens adquiridas, resultando em modo rápido e eficiente para quantificaçäo do clearance alveolo-capilar. Realizamos, a título de ilustraçäo, um teste clínico em um voluntário (35 anos, fumante, normal), que nos mostrou ser o programa adequado do ponto de vista de processamento. Adicionalmente, os resultados (pulmäo direito: 2,22 por cento/min; pulmäo esquerdo: 1,86 por cento/min) estäo de acordo com os dados encontrados na literatura