Abstract
BackgroundFecal examination is an important component of routine companion animal wellness exams. Sensitivity and specificity of fecal examinations, however, are influenced by sample preparation methodologies and the level of training and experience of personnel who read fecal slides. The VETSCAN IMAGYST system consists of three components: a sample preparation device, a commercially available scanner, and an analysis software. The VETSCAN IMAGYST automated scanner and cloud-based, deep learning algorithm, locates, classifies, and identifies parasite eggs found on fecal microscopic slides. The main study objectives were (i) to qualitatively evaluate the capabilities of the VETSCAN IMAGYST screening system and (ii) to assess and compare the performance of the VETSCAN IMAGYST fecal preparation methods to conventional fecal flotation techniques.MethodsTo assess the capabilities of VETSCAN IMAGYST screening components, fecal slides were prepared by the VETSCAN IMAGYST centrifugal and passive flotation techniques with 100 pre-screened fecal samples collected from dogs and cats and examined by both the algorithm and parasitologists. To determine the diagnostic sensitivity and specificity of the VETSCAN IMAGYST sample preparation techniques, fecal flotation slides were prepared by four different techniques (VETSCAN IMAGYST centrifugal and passive flotations, conventional centrifugal flotation, and passive flotation using OVASSAY® Plus) and examined by parasitologists. Additionally, required sample preparation and scanning times were estimated on a subset of samples to evaluate VETSCAN IMAGYST ease-of-use.ResultsThe algorithm performance of the VETSCAN IMAGYST closely matched that of the parasitologists, with Pearsonʼs correlation coefficient (r) ranging from 0.83–0.99 across four taxa of parasites, Ancylostoma, Toxocara, Trichuris and Taeniidae. Both VETSCAN IMAGYST centrifugal and passive flotation methods correlated well with conventional preparation methods on all targeted parasites (diagnostic sensitivity of 75.8–100%, specificity of 91.8–100%, qualitative agreement between methods of 93.8–94.5%). Sample preparation, slide scan and image analysis were completed within 10–14 min by VETSCAN IMAGYST centrifugal and passive flotations, respectively.ConclusionsThe VETSCAN IMAGYST scanning system with the VETSCAN IMAGYST sample preparation methods demonstrated a qualitative match in comparison to the results of parasitologists’ examinations with conventional fecal flotation techniques. The VETSCAN IMAGYST is an easy-to-use, next generation qualitative and possibly quantitative diagnostic platform that brings expert clinical results into the hands of veterinary clinics.
Highlights
Fecal examination is an important component of routine companion animal wellness exams
Algorithm performance The ability of the VETSCAN IMAGYST system to accurately identify eggs of targeted canine and feline parasites is driven by the integrated deep learning object detection algorithm that reads scanned slide images
The algorithm’s performance was assessed by comparing parasitologists’ results to the algorithm’s results on the same slide prepared either by VETSCAN IMAGYST centrifugal flotation or VETSCAN IMAGYST passive flotation (Fig. 3, Table 1). For both slide preparation methods, the VETSCAN IMAGYST diagnostic result closely matched that of the parasitologists, with a Pearson’s correlation coefficient (r) ranging between 0.83–0.99 (Fig. 3, Table 1)
Summary
Fecal examination is an important component of routine companion animal wellness exams. Sensitivity and specificity of fecal examinations, are influenced by sample preparation methodologies and the level of training and experience of personnel who read fecal slides. Fecal screening for parasitic infections in dogs and cats is an important part of wellness examinations. Standard diagnostic tests performed in most veterinary practices involve a passive or centrifugal fecal flotation followed by microscopical examination, looking for various parasitic elements, such as eggs, oocysts, cysts, larvae, and occasionally trophozoites. Diagnostic accuracy and sensitivity of fecal examinations vary widely depending on the level of training and experience of the personnel who read slides as well as the fecal preparation methods utilized at clinics [1,2,3,4,5,6,7]. Gates & Nolan [6] suggested that fecal flotation examinations performed in private practice could be missing up to half of infected dogs because of either technician error or inherent limitations to the passive flotation technique
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