Point-of-care mobile digital microscopy and deep learning for the detection of soil-transmitted helminths and Schistosoma haematobium

Oscar Holmström, Nina Linder, Billy Ngasala, Andreas Mårtensson, Ewert Linder, Mikael Lundin, Hannu Moilanen, Antti Suutala, Vinod Diwan, Johan Lundin, Oscar Holmström, Nina Linder, Billy Ngasala, Andreas Mårtensson, Ewert Linder, Mikael Lundin, Hannu Moilanen, Antti Suutala, Vinod Diwan, Johan Lundin

Abstract

Background: Microscopy remains the gold standard in the diagnosis of neglected tropical diseases. As resource limited, rural areas often lack laboratory equipment and trained personnel, new diagnostic techniques are needed. Low-cost, point-of-care imaging devices show potential in the diagnosis of these diseases. Novel, digital image analysis algorithms can be utilized to automate sample analysis.

Objective: Evaluation of the imaging performance of a miniature digital microscopy scanner for the diagnosis of soil-transmitted helminths and Schistosoma haematobium, and training of a deep learning-based image analysis algorithm for automated detection of soil-transmitted helminths in the captured images.

Methods: A total of 13 iodine-stained stool samples containing Ascaris lumbricoides, Trichuris trichiura and hookworm eggs and 4 urine samples containing Schistosoma haematobium were digitized using a reference whole slide-scanner and the mobile microscopy scanner. Parasites in the images were identified by visual examination and by analysis with a deep learning-based image analysis algorithm in the stool samples. Results were compared between the digital and visual analysis of the images showing helminth eggs.

Results: Parasite identification by visual analysis of digital slides captured with the mobile microscope was feasible for all analyzed parasites. Although the spatial resolution of the reference slide-scanner is higher, the resolution of the mobile microscope is sufficient for reliable identification and classification of all parasites studied. Digital image analysis of stool sample images captured with the mobile microscope showed high sensitivity for detection of all helminths studied (range of sensitivity = 83.3-100%) in the test set (n = 217) of manually labeled helminth eggs.

Conclusions: In this proof-of-concept study, the imaging performance of a mobile, digital microscope was sufficient for visual detection of soil-transmitted helminths and Schistosoma haematobium. Furthermore, we show that deep learning-based image analysis can be utilized for the automated detection and classification of helminths in the captured images.

Keywords: Neglected tropical diseases; computer vision; global health; helminth; mHealth for Improved Access and Equity in Health Care; point-of-care.

Conflict of interest statement

Johan Lundin and Mikael Lundin are founders and co-owners of Fimmic Oy, Helsinki, Finland.

Figures

Figure 1.
Figure 1.
MoMic digital microscope scanner (1) with external motor unit attached (2). The microscope glass (3) is placed in the slide holder (4), which is placed in the microscope and navigated from the motor unit. The device is connected to and operated from a laptop computer (5) running software (6) for operation of the device.
Figure 2.
Figure 2.
Region of glass slide captured with the mobile microscope. Enlarged areas (right) showing A. lumbricoides eggs in sample (magnified images showing native, full resolution of captured images at 100% digital magnification).
Figure 3.
Figure 3.
Stool sample showing A. lumbricoides eggs, digitized with (a) mobile microscope, and (b) reference slide-scanner.
Figure 4.
Figure 4.
Captured images with the mobile microscopes with visible parasites. Enlarged areas showing the parasites at 300% digital zoom. (a) A. lumbricoides, (b) T. trichiura, (c) hookworm, (d) S. haematobium.
Figure 5.
Figure 5.
Results of digital image analysis of fixated stool sample (A. lumbricoides infection), showing detected regions of interest of fixated stool sample, sorted by certainty of representing parasite (descending order, from most likely candidates to least likely), as detected by the image analysis software.

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Source: PubMed

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