Early detection and accurate diagnosis can predict the risk of malignant disease transformation, thereby increasing the probability of effective treatment. Identifying mild syndrome with small pathological regions serves as an ominous warning and is fundamental in the early diagnosis of diseases. While deep learning algorithms, particularly convolutional neural networks (CNNs), have shown promise in segmenting medical objects, analyzing small areas in medical images remains challenging. This difficulty arises due to information losses and compression defects from convolutional and pooling operations in CNNs, which become more pronounced as the network deepens, especially for small medical objects. To address these challenges, we propose a novel scale-variant attention-based network (SvANet) for accurately segmenting small-scale objects in medical images. The SvANet consists of scale-variant attention (SvAttn), cross-scale guidance, Monte Carlo attention (MCAttn), and Vision Transformer (ViT), which incorporates cross-scale features and alleviates compression artifacts for enhancing the discrimination of small medical objects. Quantitative experimental results demonstrate the superior performance of SvANet, achieving 96.12%, 96.11%, 89.79%, 84.15%, 80.25%, 73.05%, and 72.58% in mean Dice (mDice) coefficient for segmenting kidney tumors, skin lesions, hepatic tumors, polyps, surgical excision cells, retinal vasculatures, and sperms, which occupy less than 1% of the image areas in KiTS23, ISIC 2018, ATLAS, PolypGen, TissueNet, FIVES, and SpermHealth datasets, respectively.

An unbiased assessment of sperm morphology and motility is crucial for assessing fertility potential and guiding visual feedback for microrobotic manipulation. Automated analysis and selection of optimal sperm are essential for in vitro fertilization treatments, such as robotic intracytoplasmic sperm injection. However, conventional image processing methods face limitations in analyzing small sperm objects under microscopic imaging. While convolutional neural networks (CNNs) have brought promising advancements in microscopic image analysis, previous CNN methods have struggled to accurately differentiate tiny objects. These methods often require staining or fluorescence techniques to enhance visual contrast between sperm and culture medium, leading to clinical impracticality. To address these limitations, we introduce a novel sperm recognition network named the sperm feature-correlated network (SFCNet), for accurate and efficient segmentation and tracking of minute sperm objects. The SFCNet employs innovative modules, including collateral multi-scale convolution, cross-scale feature map guide, atrous spatial pyramid convolution with pooling, lateral attention, and multi-scale tracking proposal, to preserve essential sperm details despite their small size. Experimental results indicate that the SFCNet surpassed the state-of-the-art models designed for segmenting or tracking small objects, achieving up to a 28.39% higher Sorensen-Dice coefficient in segmentation and a 10.33% higher average precision in tracking. Additionally, the SFCNet excelled in sperm morphometric analysis, achieving errors below 15%. Moreover, the SFCNet also secured top-tier performance in sperm motility analysis, acquiring errors below 13% in seven sperm motility parameters.Note to Practitioners—This study is stimulated by the need to analyze the quality of motile sperms and select the optimal one for in vitro fertilization. Existing methods for detecting sperm fall short as they require a relatively high-magnification microscopic image or the usage of stain or fluorescence to increase sperm visualization, which limits the selection process or even makes the sperm clinically unavailable. To overcome these limitations, the present work proposes a new framework based on deep learning, which includes the design of extracting multi-scale sperm features. Experimental results suggest that the proposed method can perform better than existing methods in real-time analysis of multiple motile sperms’ morphology and motility at 20$\times$objective. In the future, there is a high potential for fertility specialists and healthcare workers to apply the presented framework in fertility treatment with higher accuracy and efficiency.

Minimum-cost consensus (MCC) is an effective technique for reducing differences of opinion in group decision-making that is sensitive to adjustment costs. Classical MCC aims to obtain an optimal solution regarding the consensus reaching process (CRP) with the objective function of minimizing the group adjustment cost. However, the following limitations exist: 1) the absolute adjustment cost is usually employed as the sole criterion, which is susceptible to the uneven distribution of individual opinions; and 2) while some MCC models account for over-adjustment, how to prevent over-adjustment in the CRP with relative adjustment costs remains almost unexplored. To this end, this study proposes minimum-relative-cost consensus (MRCC) models based on personalized feedback constraints. First, the concept of relative adjustment cost is defined. The notion of personalized feedback constraint is introduced to take full account for individual willingness to adjust their respective opinions. According to different types of consensus constraints, three personalized feedback constraint-driven MRCC models are constructed. We then perform the cost analysis, which shows that MRCC changes the acting mechanism of classical MCC on CRP. In addition, we explore the integration of MCC and MRCC to fully utilize the advantages of both. Finally, a case study of online healthcare community knowledge services and the comparative analysis reveals the feasibility and advantages of the models.

Unbiased measurement of sperm morphometric and motility parameters is essential for assessing fertility potential and guiding visual feedback for microrobotic manipulation. Automated analysis of multiple sperms and selection of an optimal sperm is crucial for in vitro fertilisation treatment such as robotic intracytoplasmic sperm injection. However, conventional image processing methods have limitations in analysing small sperm objects under microscopic imaging. The emergence of convolutional neural networks (CNNs) has offered promising advancements in microscopic image analysis. However, previous CNN methods have struggled to accurately segment tiny objects, requiring staining or fluorescence techniques to enhance visual contrast between sperm and culture medium, leading to clinical impracticality. To address these limitations, we introduce a novel segmentation network named the cross-scale guidance (CSG) network for accurate and efficient segmentation of minute sperm objects. The CSG network employs innovative modules, including collateral multi-scale convolution, cross-scale feature map guide, and multi-scale feature fusion, to preserve essential sperm details despite their small size. Experimental results indicate that the CSG network surpassed the state-of-the-art models designed for small object segmentation, achieving a significant increase up to 18.62% higher mean intersection over union (mIoU). Additionally, the CSG network excelled in sperm morphometric analysis, achieving errors below 20%. Moreover, sperm motility parameters were further derived from the segmentation results for comprehensive sperm fertility analysis.

Cell counting is an essential step in a wide variety of biomedical applications, such as blood examination, semen assessment, and cancer diagnosis. However, microscopic cell counting is conventionally labor-intensive and error-prone for experts, and most of the existing automatic approaches are confined to a specific image type. To address these challenges, we propose a new interactive dual-network framework for automatic and generic cell counting. In this framework, one deep learning model (counter) is trained to regress a density map from a given microscope image. The number of cells in that image can be estimated by performing integration over the regressed density map. Another network (ground truth generator) is employed to dynamically generate suitable ground truth based on the cell samples and the dot annotations to serve as the supervision for training the counter. The interactive process to obtain the optimal model is achieved by jointly training the counter and ground truth generator iteratively. Moreover, we design a hierarchical multi-scale attention-based architecture to act as the counter in the proposed framework. This architecture is crafted to efficiently and effectively process multi-level features, enabling accurate regression of high-quality density maps. Evaluation experiments on three public cell counting datasets demonstrate the superiority of our method.Note to Practitioners—This paper is motivated by the need for advanced healthcare in the deep learning era. As a routine assessment procedure in healthcare settings, cell counting usually suffers from poor accuracy and inefficiency. We provide a solution to ameliorate the situation by developing a deep learning-based framework for automatic cell counting. After being trained in an end-to-end manner, the dual-network system is able to estimate the number of cells from the given microscopic images more accurately than existing methods. Additionally, this method is robust in various scenarios, such as calculating cell populations in suspension and cells in tissues. In the future, the presented pipeline has the potential to be implemented by biomedical practitioners who are non-expert in programming via wrapping it into a graphical user interface.

Accurate and unbiased examinations of skin lesions are critical for the early diagnosis and treatment of skin diseases. Visual features of skin lesions vary significantly because the images are collected from patients with different lesion colours and morphologies by using dissimilar imaging equipment. Recent studies have reported that ensembled convolutional neural networks (CNNs) are practical to classify the images for early diagnosis of skin disorders. However, the practical use of these ensembled CNNs is limited as these networks are heavyweight and inadequate for processing contextual information. Although lightweight networks (e.g., MobileNetV3 and EfficientNet) were developed to achieve parameter reduction for implementing deep neural networks on mobile devices, insufficient depth of feature representation restricts the performance. To address the existing limitations, we develop a new lite and effective neural network, namely HierAttn. The HierAttn applies a novel deep supervision strategy to learn the local and global features by using multi-stage and multi-branch attention mechanisms with only one training loss. The efficacy of HierAttn was evaluated by using the dermoscopy images dataset ISIC2019 and smartphone photos dataset PAD-UFES-20 (PAD2020). The experimental results show that HierAttn achieves the best accuracy and area under the curve (AUC) among the state-of-the-art lightweight networks.

Microscopic cell detection is a challenging task due to significant inter-cell occlusions in dense clusters and diverse cell morphologies. This paper introduces a novel framework designed to enhance automated cell detection. The proposed approach integrates a deep learning model that produces an inverse distance transform-based detection map from the given image, accompanied by a secondary network designed to regress a cell density map from the same input. The inverse distance transform-based map effectively highlights each cell instance in the densely populated areas, while the density map accurately estimates the total cell count in the image. Then, a custom counting-aided cell center extraction strategy leverages the cell count obtained by integrating over the density map to refine the detection process, significantly reducing false responses and thereby boosting overall accuracy. The proposed framework demonstrated superior performance with F-scores of 96.93%, 91.21%, and 92.00% on the VGG, MBM, and ADI datasets, respectively, surpassing existing state-of-the-art methods. It also achieved the lowest distance error, further validating the effectiveness of the proposed approach. These results demonstrate significant potential for automated cell analysis in biomedical applications.

Accurate position feedback in a wide range is critical for medical microrobotics and robot-assisted examinations, such as colonoscopy, bronchoscopy and capsule endoscopy examination. Among the many modalities of positioning feedback, magnetic tracking is a preferable method due to the unique advantages of free line of sight, free energy storage and untethered connection. However, the field strength of the magnetic source decreases with the third power of the distance, limiting the effectiveness of position feedback at long distances. In order to maintain a consistently high tracking accuracy in a broad area, this paper presents a new dynamic tracking solution by applying a movable sensor array. In this new solution, the tracking accuracy of the magnet is first determined and optimized within a short range. When the target microrobot carrying the magnet exceeds this optimized range, the sensor array is relocated by an external robotic arm to keep the target in the effective tracking range. Moreover, we also propose a multi-point locating algorithm to minimize the varying background noise. Experimental results show that the proposed method increases the range of magnetic tracking and achieves a satisfactory level of tracking accuracy, which demonstrates significant potentials to improve the position feedback of microrobots in medical applications.