Color Calibration In Digital Pathology: The Clinical Impact Of A Novel Test Object

Introduction/ Background Guidance from the Food and Drug Administration has recommended color standardization for whole slide imaging, as with all other digital systems. However there is known, unresolved and substantial variation in color between digital slide scanners. To address this issue, we created a novel color calibration test object which uniquely utilizes histochemical stains and a tissue-like substrate, affording accurate internal calibration of WSIs. Aims We aimed to evaluate the clinical application of the novel test object. Objectives included: 1. Whether calibration made WSIs appear closer in color to the glass slide counterpart; 2. Whether pathologists prefer calibrated WSIs; and, 3. Whether calibration affected diagnostic confidence. Methods Six pathology cases that present known difficulties when viewed using a digital microscope were selected and WSIs were generated. These WSIs were calibrated using a color ICC profile created using spectral measurements from the test object. Twelve pathologists, blinded to intervention, compared calibrated and uncalibrated versions of each WSI on a medical-grade monitor. The display was color calibrated using a colorimeter which accounted for ambient lighting. Three, subjective responses were recorded on 7-point Likert scales. Results Calibrated WSIs were closer in appearance to the microscope in 40 of 72 trials, (56%) and were preferred in 46 of 72 trials (64%). Calibration improved diagnostic confidence (median 6.00 vs. 5.00, p=0.001). Diagnostic confidence with the calibrated slides was correlated with preference for color calibration (r=0.499; p<0.001)

The variation of radiologists' performance over the course of a reading session

The radiologist's task of reviewing many cases successively is highly repetitive and requires a high level of concentration. Fatigue effects have, for example, been shown in studies comparing performance at different times of day. However, little is known about changes in performance during an individual reading session. During a session reading an enriched case set, performance may be affected by both fatigue (i.e. decreasing performance) and training (i.e. increasing performance) effects. In this paper, we reanalyze 3 datasets from 4 studies for changes in radiologist performance during a reading session. Studies feature 8-20 radiologists reading and assessing 27-60 cases in single, uninterrupted sessions. As the studies were not designed for this analysis, study setups range from bone fractures to mammograms and randomization varies between studies. Thus, they are analyzed separately using mixed-effects models. There is some indication that, as time goes on, specificity increases (shown with p<0.05 for 2 out of 3 datasets, no significant difference for the other) while sensitivity may also increase (p<0.05 for 1 out of 3 datasets). The difficulty of 'normal' (healthy / non-malignant) and 'abnormal' (unhealthy / malignant) cases differs (p<0.05 for 3 out of 3 datasets) and the reader's experience may also be relevant (p<0.05 for 1 out of 3 datasets). These results suggest that careful planning of breaks and session length may help optimize reader performance. Note that the overall results are still inconclusive and a targeted study to investigate fatigue and training effects within a reading session is recommended. © 2013 SPIE

Retrospective review of the drop in observer detection performance over time in lesion-enriched experimental studies.

The vigilance decrement describes a decrease in sensitivity or increase in specificity with time on task. It has been observed in a variety of repetitive visual tasks, but little is known about these patterns in radiologists. We investigated whether there is systematic variation in performance over the course of a radiology reading session. We re-analyzed data from six previous lesion-enriched radiology studies. Studies featured 8-22 participants assessing 27-100 cases (including mammograms, chest CT, chest x-ray, and bone x-ray) in a reading session. Changes in performance and speed as the reading session progressed were analyzed using mixed effects models. Time taken per case decreased 9-23% as the reading session progressed (p < 0.005 for every study). There was a sensitivity decrease or specificity increase over the course of reading 100 chest x-rays (p = 0.005), 60 bone fracture x-rays (p = 0.03), and 100 chest CT scans (p < 0.0001). This effect was not found in the shorter mammography sessions with 27 or 50 cases. We found evidence supporting the hypothesis that behavior and performance may change over the course of reading an enriched test set. Further research is required to ascertain whether this effect is present in radiological practice

Breast cancer in Mongolia: an increasingly important health policy issue

Delgermaa Demchig,&nbsp;Claudia Mello-Thoms,&nbsp;Patrick C Brennan Medical Image Optimization and Perception Group (MIOPeG), Faculty of Health Science, The University of Sydney, Sydney, NSW, Australia Abstract: Breast cancer is a leading cause of cancer-related death for women in both developed and developing countries. The incidence and mortality of breast cancer in Mongolia, while low compared with other counties, has been increasing on an annual basis. In addition, in Mongolia, approximately 90% of the patients are diagnosed at a late stage, resulting in high mortality, with the majority of individuals diagnosed with breast cancer dying within 5 years of diagnosis. Breast cancer screening plays an important role in reducing mortality in Western countries and has been adopted by a number of Asian countries; however, no such approach exists in Mongolia. In a country of limited resources, implementation of expensive health strategies such as screening requires effective allocations of resources and the identification of the most effective imaging methods. This requirement relies on recent accurate data; however, at this time, there is a paucity of information around breast cancer in Mongolia. Until data around features of the disease are available, effective strategies to diagnose breast cancer that recognize the economic climate in Mongolia cannot be implemented and the impact of breast cancer is likely to increase. Keywords: incidence, mortality, breast screening, Mongoli

Computer-based image analysis in breast pathology

Whole slide imaging (WSI) has the potential to be utilized in telepathology, teleconsultation, quality assurance, clinical education, and digital image analysis to aid pathologists. In this paper, the potential added benefits of computer-assisted image analysis in breast pathology are reviewed and discussed. One of the major advantages of WSI systems is the possibility of doing computer-based image analysis on the digital slides. The purpose of computer-assisted analysis of breast virtual slides can be (i) segmentation of desired regions or objects such as diagnostically relevant areas, epithelial nuclei, lymphocyte cells, tubules, and mitotic figures, (ii) classification of breast slides based on breast cancer (BCa) grades, the invasive potential of tumors, or cancer subtypes, (iii) prognosis of BCa, or (iv) immunohistochemical quantification. While encouraging results have been achieved in this area, further progress is still required to make computer-based image analysis of breast virtual slides acceptable for clinical practice

Reporting instructions significantly impact false positive rates when reading chest radiographs

Objectives: To determine the impact of specific reporting tasks on the performance of radiologists when reading chest radiographs. Methods: Ten experienced radiologists read a set of 40 postero-anterior (PA) chest radiographs: 21 nodule free and 19 with a proven solitary nodule. There were two reporting conditions: an unframed task (UFT) to report any abnormality and a framed task (FT) reporting only lung nodule/s. Jackknife free-response operating characteristic (JAFROC) figure of merit (FOM), specificity, location sensitivity and number of true positive (TP), false positive (FP), true negative (TN) and false negative (FN) decisions were used for analysis. Results: JAFROC FOM for tasks showed a significant reduction in performance for framed tasks (P = 0.006) and an associated decrease in specificity (P = 0.011) but no alteration to the location sensitivity score. There was a significant increase in number of FP decisions made during framed versus unframed tasks for nodule-containing (P = 0.005) and nodule-free (P = 0.011) chest radiographs. No significant differences in TP were recorded. Conclusions: Radiologists report more FP decisions when given specific reporting instructions to search for nodules on chest radiographs. The relevance of clinical history supplied to radiologists is called into question and may induce a negative effect. Key Points: • Framed reporting tasks increases false positive rates when searching for pulmonary nodules • False positive results were observed in both nodule-containing and nodule-free cases • Radiologist’s decision-making may be influenced by clinical history in thoracic imagin

Understanding recall rates in screening mammography : a conceptual framework review of the literature

Recall rates are one of the performance measures used to evaluate the effectiveness of mammography screening programs. There is conflicting evidence regarding the link between recall rates and cancer detection rates and a variety of differing recall rates exist between countries and readers. This variability in recall rates may have important clinical and economic implications such as unnecessary follow-up procedures, additional costs to the health care system and psychological effects for the women themselves associated with false-positive mammograms results. In order to reduce the impact of false positive recall rates in screening mammography, it is essential for all multidisciplinary health care providers, especially those in medical imaging, to fully understand the factors that may contribute and affect recall rates. The multifactorial nature of recall rates is explored in this paper through the construction of a conceptual map based on a review of the current literature