Browsing by Author "Brenes, David"

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    Automated In Vivo High-Resolution Imaging to Detect Human Papillomavirus–Associated Anal Precancer in Persons Living With HIV
    (Wolters Kluwer, 2023) Brenes, David; Kortum, Alex; Carns, Jennifer; Mutetwa, Tinaye; Schwarz, Richard; Liu, Yuxin; Sigel, Keith; Richards-Kortum, Rebecca; Anandasabapathy, Sharmila; Gaisa, Michael; Chiao, Elizabeth; Bioengineering
    INTRODUCTION: In the United States, the effectiveness of anal cancer screening programs has been limited by a lack of trained professionals proficient in high-resolution anoscopy (HRA) and a high patient lost-to-follow-up rate between diagnosis and treatment. Simplifying anal intraepithelial neoplasia grade 2 or more severe (AIN 2+) detection could radically improve the access and efficiency of anal cancer prevention. Novel optical imaging providing point-of-care diagnoses could substantially improve existing HRA and histology-based diagnosis. This work aims to demonstrate the potential of high-resolution microendoscopy (HRME) coupled with a novel machine learning algorithm for the automated, in vivo diagnosis of anal precancer. METHODS: The HRME, a fiber-optic fluorescence microscope, was used to capture real-time images of anal squamous epithelial nuclei. Nuclear staining is achieved using 0.01% wt/vol proflavine, a topical contrast agent. HRME images were analyzed by a multitask deep learning network (MTN) that computed the probability of AIN 2+ for each HRME image. RESULTS: The study accrued data from 77 people living with HIV. The MTN achieved an area under the receiver operating curve of 0.84 for detection of AIN 2+. At the AIN 2+ probability cutoff of 0.212, the MTN achieved comparable performance to expert HRA impression with a sensitivity of 0.92 (P = 0.68) and specificity of 0.60 (P = 0.48) when using histopathology as the gold standard. DISCUSSION: When used in combination with HRA, this system could facilitate more selective biopsies and promote same-day AIN2+ treatment options by enabling real-time diagnosis.
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    Development of a multimodal mobile colposcope for real-time cervical cancer detection
    (Optica Publishing Group, 2022) Coole, Jackson B.; Brenes, David; Possati-Resende, Júlio César; Antoniazzi, Márcio; Fonseca, Bruno de Oliveira; Maker, Yajur; Kortum, Alex; Vohra, Imran S.; Schwarz, Richard A.; Carns, Jennifer; Souza, Karen Cristina Borba; Santana, Iara Viana Vidigal; Kreitchmann, Regis; Salcedo, Mila P.; Salcedo, Mila P.; Ramanujam, Nirmala; Schmeler, Kathleen M.; Richards-Kortum, Rebecca; Bioengineering
    Cervical cancer remains a leading cause of cancer death among women in low-and middle-income countries. Globally, cervical cancer prevention programs are hampered by a lack of resources, infrastructure, and personnel. We describe a multimodal mobile colposcope (MMC) designed to diagnose precancerous cervical lesions at the point-of-care without the need for biopsy. The MMC integrates two complementary imaging systems: 1) a commercially available colposcope and 2) a high speed, high-resolution, fiber-optic microendoscope (HRME). Combining these two image modalities allows, for the first time, the ability to locate suspicious cervical lesions using widefield imaging and then to obtain co-registered high-resolution images across an entire lesion. The MMC overcomes limitations of high-resolution imaging alone; widefield imaging can be used to guide the placement of the high-resolution imaging probe at clinically suspicious regions and co-registered, mosaicked high-resolution images effectively increase the field of view of high-resolution imaging. Representative data collected from patients referred for colposcopy at Barretos Cancer Hospital in Brazil, including 22,800 high resolution images and 9,900 colposcope images, illustrate the ability of the MMC to identify abnormal cervical regions, image suspicious areas with subcellular resolution, and distinguish between high-grade and low-grade dysplasia.
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    High frame rate video mosaicking microendoscope to image large regions of intact tissue with subcellular resolution
    (Optical Society of America, 2021) Hunt, Brady; Coole, Jackson; Brenes, David; Kortum, Alex; Mitbander, Ruchika; Vohra, Imran; Carns, Jennifer; Schwarz, Richard; Richards-Kortum, Rebecca; Bioengineering
    High-resolution microendoscopy (HRME) is a low-cost strategy to acquire images of intact tissue with subcellular resolution at frame rates ranging from 11 to 18 fps. Current HRME imaging strategies are limited by the small microendoscope field of view (∼0.5 mm2); multiple images must be acquired and reliably registered to assess large regions of clinical interest. Image mosaics have been assembled from co-registered frames of video acquired as a microendoscope is slowly moved across the tissue surface, but the slow frame rate of previous HRME systems made this approach impractical for acquiring quality mosaicked images from large regions of interest. Here, we present a novel video mosaicking microendoscope incorporating a high frame rate CMOS sensor and optical probe holder to enable high-speed, high quality interrogation of large tissue regions of interest. Microendoscopy videos acquired at >90 fps are assembled into an image mosaic. We assessed registration accuracy and image sharpness across the mosaic for images acquired with a handheld probe over a range of translational speeds. This high frame rate video mosaicking microendoscope enables in vivo probe translation at >15 millimeters per second while preserving high image quality and accurate mosaicking, increasing the size of the region of interest that can be interrogated at high resolution from 0.5 mm2 to >30 mm2. Real-time deployment of this high-frame rate system is demonstrated in vivo and source code made publicly available.