{"id":3588,"date":"2015-11-19T22:40:28","date_gmt":"2015-11-19T22:40:28","guid":{"rendered":"http:\/\/www.kurzweilai.net\/?p=267228"},"modified":"2015-11-20T02:29:40","modified_gmt":"2015-11-20T02:29:40","slug":"pigeons-diagnose-breast-cancer-on-x-rays-as-well-as-radiologists","status":"publish","type":"post","link":"https:\/\/hoo.central12.com\/fugic\/2015\/11\/19\/pigeons-diagnose-breast-cancer-on-x-rays-as-well-as-radiologists\/","title":{"rendered":"Pigeons diagnose breast cancer on X-rays as well as radiologists"},"content":{"rendered":"
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The pigeons’ training environment included a food pellet dispenser, a touch-sensitive screen which projected the medical image, as well as blue and yellow choice buttons on either side of the image. Pecks to those buttons and to the screen were automatically recorded. (credit: Levenson RM et al.\/PloS)<\/p><\/div>\n

“Pigeons do just as well as humans in categorizing digitized slides and mammograms of benign and malignant human breast tissue,\u201d said\u00a0Richard Levenson<\/a>,\u00a0professor of\u00a0pathology and laboratory medicine<\/a>\u00a0at UC Davis Health System and lead author of\u00a0a new open-access study<\/a>\u00a0in PLoS One<\/em> by researchers at the\u00a0University of California, Davis<\/a>\u00a0and The University of Iowa<\/a>.<\/p>\n

\u201cThe pigeons were able to generalize what they had learned, so that when we showed them a completely new set of normal and cancerous digitized slides, they correctly identified them,\u201d Levenson\u00a0 said. \u201cThe pigeons also learned to correctly identify cancer-relevant microcalcifications on mammograms, but they had a tougher time classifying suspicious masses on mammograms — a task that is extremely difficult, even for skilled human observers.\u201d<\/p>\n

Although a pigeon\u2019s brain is no bigger than the tip of an index finger, the neural pathways involved operate in ways very similar to those at work in the human brain. \u201cResearch over the past 50 years has shown that pigeons can distinguish identities and emotional expressions on human faces, letters of the alphabet, misshapen pharmaceutical capsules, and even paintings by Monet vs. Picasso,\u201d said\u00a0Edward Wasserman<\/a>, professor of psychological and brain sciences at The University of Iowa and co-author of the study. \u201cTheir visual memory is equally impressive, with a proven recall of more than 1,800 images.\u201d<\/p>\n

Pigeons rival radiologists at discriminating breast cancer
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Examples of benign (left) and malignant (right) breast specimens stained with hematoxylin and eosin, at different magnifications. The birds were remarkably adept at discriminating between benign and malignant breast cancer slides at all magnifications, a task that can perplex inexperienced human observers, who typically require considerable training to attain mastery. (credit: Levenson RM et al.\/PloS)<\/p><\/div>\n

For the study, each pigeon learned to discriminate cancerous from non-cancerous images and slides using traditional \u201coperant conditioning,\u201d a technique in which a bird was rewarded only when a correct selection was made; incorrect selections were not rewarded and prompted correction trials. Training with stained pathology slides included a large set of benign and cancerous samples from routine cases at UC Davis Medical Center.<\/p>\n

\u201cThe birds were remarkably adept at discriminating between benign and malignant breast cancer slides at all magnifications, a task that can perplex inexperienced human observers, who typically require considerable training to attain mastery,\u201d Levenson said. He said the pigeons achieved nearly 85 percent correct within 15 days.<\/p>\n

Flock-sourcing: 99 percent accuracy
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\u201cWhen we showed a cohort of four birds a set of uncompressed images, an approach known as \u201cflock-sourcing,\u201d the group\u2019s accuracy level reached an amazing 99 percent correct, higher than that achieved by any of the four individual birds.\u201d Wasserman has conducted studies on pigeons for more than 40 years.<\/p>\n

The birds, however, had difficulty evaluating the malignant potential of breast masses (without microcalcifications) detected on mammograms, a task the authors acknowledge as \u201cvery challenging.\u201d<\/p>\n

After years of education and training, physicians can sometimes struggle with the interpretation of microscope slides and mammograms. Levenson, a pathologist who studies artificial intelligence for image analysis and other applications in biology and medicine, believes there is considerable room for enhancing the process.<\/p>\n

\u201cWhile new technologies are constantly being designed to enhance image acquisition, processing, and display, these potential advances need to be validated using trained observers to monitor quality and reliability,\u201d Levenson said. \u201cThis is a difficult, time-consuming, and expensive process that requires the recruitment of clinicians as subjects for these relatively mundane tasks. \u201cPigeons\u2019 sensitivity to diagnostically salient features in medical images suggest that they can provide reliable feedback on many variables at play in the production, manipulation, and viewing of these diagnostically crucial tools, and can assist researchers and engineers as they continue to innovate.\u201d<\/p>\n

This work also suggests that pigeons\u2019 remarkable ability to discriminate between complex visual images could be put to good use as trained medical image observers, to help researchers explore image quality and the impact of color, contrast, brightness, and image compression artifacts on diagnostic performance.<\/p>\n