Diagnostic Pathology BioMed Central (original) (raw)

Quality evaluation of microscopy and scanned histological images for diagnostic purposes

Micron, 2012

In this work we present a study for assessing and comparing the fidelity of biopsy and cytology images captured with two different devices, that is optical microscopes and scanners, at 40× magnification in bright field. The devices use different ways to magnify images. Microscopes use a set of lenses while scanners capture light through arrays of micro-photoreceptors. The objective is to carry out a quantitative evaluation to discern which of the two devices provides better image quality in terms of contrast, colour and stain. Since there is no unanimous consensus on quality metrics, we will make use of both an objective metric based on perceptual features, together with a subjective psychophysical test as the International Telecommunications Union (ITU) recommends in ITU-R BT.500 for such type of tests. Both techniques indicate a slight preference for the scanner over the microscope in terms of better image quality, considering defocus as the main problem followed by colour distortions. However, the image quality of both devices is suitable for clinical, educational and research purposes.

Automatic Image Quality Assessment in Digital Pathology: From Idea to Implementation

At this time, the quality of a Whole Slide Image (WSI) is verified a posteriori by a technician or a pathologist. A WSI of insufficient quality needs to be scanned again. High-speed automatic quality assessment tools for WSI will therefore greatly improve laboratory workflow. We describe here a fast method to automatically assess WSI quality, with different tests such as blurriness, contrast, brightness and color, and to accept or discard them at the time of acquisition in less than a minute. Parameters are weighted by pertinence and a global score indicates whether the WSI is suitable for further use. This fast method, designed at first to improve laboratory workflow, is currently being implemented in a network of 27 French hospitals and public-private health institutions in the Paris region. It may also be used as a calibration and quality control tool for WSI acquisition systems.

Evaluation of Diagnostic Image Quality

This paper examines three definitions of diagnostic image quality: diagnostic sensitivity and specificity; expert evaluation of contrast, resolution and noise; and quantitative analysis of photon statistics, limitations of recording systems, and limitations of the human visual system.

Validation of digital pathology imaging for primary histopathological diagnosis

Histopathology, 2015

Digital Pathology (DP) offers advantages over glass slide microscopy (GS), but data demonstrating a statistically valid equivalent (i.e. non-inferior) performance of DP against GS is required to permit its use in diagnosis. Seventeen pathologists re-reported 3,017 cases by DP. Of these 1,009 were re-reported by the same pathologist and 2,008 by a different pathologist. Re-examination of 10,138 scanned slides (2.22 terabytes) produced 72 variances between GS and DP reports, including 21 clinically significant variances. Ground truth lay with GS in 12 and DP in 9 cases. These results are within the 95% confidence interval for existing intra- and inter- observer variability, proving DP is non-inferior to GS. In three cases the digital platform was deemed responsible for the variance, including a gastric biopsy where Helicobacter pylori only became visible on slides scanned at the x60 setting, and a bronchial biopsy and penile biopsy where dysplasia was reported on DP but not present on...

Validation of Whole Slide Imaging for Primary Diagnosis in Surgical Pathology

Archives of Pathology & Laboratory Medicine, 2013

Context.—High-resolution scanning technology provides an opportunity for pathologists to make diagnoses directly from whole slide images (WSIs), but few studies have attempted to validate the diagnoses so obtained.Objective.—To compare WSI versus microscope slide diagnoses of previously interpreted cases after a 1-year delayed re-review (“wash-out”) period.Design.—An a priori power study estimated that 450 cases might be needed to demonstrate noninferiority, based on a null hypothesis: “The true difference in major discrepancies between WSI and microscope slide review is greater than 4%.” Slides of consecutive cases interpreted by 2 pathologists 1 year prior were retrieved from files, and alternate cases were scanned at original magnification of ×20. Each pathologist reviewed his or her cases using either a microscope or imaging application. Independent pathologists identified and classified discrepancies; an independent statistician calculated major and minor discrepancy rates for ...

Digital Image Analysis in Pathology: Benefits and Obligation

Analytical Cellular Pathology, 2012

Pathology has recently entered the era of personalized medicine. This brings new expectations for the accuracy and precision of tissue-based diagnosis, in particular, when quantification of histologic features and biomarker expression is required. While for many years traditional pathologic diagnosis has been regarded as ground truth, this concept is no longer sufficient in contemporary tissue-based biomarker research and clinical use. Another major change in pathology is brought by the advancement of virtual microscopy technology enabling digitization of microscopy slides and presenting new opportunities for digital image analysis. Computerized vision provides an immediate benefit of increased capacity (automation) and precision (reproducibility), but not necessarily the accuracy of the analysis. To achieve the benefit of accuracy, pathologists will have to assume an obligation of validation and quality assurance of the image analysis algorithms. Reference values are needed to measure and control the accuracy. Although pathologists' consensus values are commonly used to validate these tools, we argue that the ground truth can be best achieved by stereology methods, estimating the same variable as an algorithm is intended to do. Proper adoption of the new technology will require a new quantitative mentality in pathology. In order to see a complete and sharp picture of a disease, pathologists will need to learn to use both their analogue and digital eyes.