Radiology in Epidemic Monitoring

Radiology Detecting Epidemics: Enhanced Vision for Public Health
 

How would the world know if an influenza epidemic were on the rise? How can public health departments become armed with the very best information on the population’s state of health?  This is the science of epidemiology, in which scientists and doctors track and analyze the patterns of disease so that we can identify where the disease started, what is causing the disease to spread, and how to prevent, contain, and eradicate the threat.
 
A new partner in this effort is radiology.  In the days before the digital age, when radiology CT scans and radiographs (or ‘X-rays’) were printed films, it was very difficult to integrate radiology information with the rest of the medical record. Now that radiology is increasingly digital and stored as computer files, and radiology reports are digital documents, these data-points can be stored, searched, and analyzed.  This means that this data can now flow to public health departments for tracking whether a new disease is appearing and spreading.  
 
The common concern in any public health reporting system is the preservation of patient confidentiality and privacy, which is regulated by HIPAA, and the Department of Health and Human Services passed the Standards of Privacy of Individually Identifiable Health Information (‘Privacy Rule’) to ensure against the inappropriate sharing of patient information.  To protect the public against outbreak, physicians may disclose information to public health officials about patients who may have been exposed to a disease or who are at risk of spreading the disease.  Nevertheless, protecting the public means balancing the protection of privacy with the collective protection of populations.
 
The technical barrier for radiology’s integration with public health initiatives is the need for synchronizing the information.  For example, if radiologists are using different terms in their reports to describe and diagnose a particular disease, it creates a language barrier for the computer systems to create a reliable database.  For this reason ontologies (which are maps of how words are related to each other) are being developed by radiology professional societies to develop a common language of radiology reports for better harmonization of terms, while using the foundations set by other specialists for medical terminology, such as Systematized Nomenclature of Medicine Clinical Terms (SNOMED CT) which was developed by the College of American Pathologists.
 
Members of RAD-AID have been hard at work on technologies and research to integrate radiology data into public health department tracking systems with test-platforms in the Washington DC metropolitan area (Mollura DJ, et al. JACR March 2008).  For example, if a patient comes to the hospital with fever and a cough.  It turns out that this combination is very nonspecific and does not point to one particular diagnosis. But, the imaging, such as a chest radiograph or a chest CT adds a great deal of information.  So, when that information is integrated into the rest of the medical record, the public health data set becomes more robust and responsive.
 
A time of increasing integration of medical information via electronic system is arriving.  However, like many trends in medicine, the trend is mainly located in developed countries where more resources are available for technology investment.  For example, the US is rapidly becoming more electronically based, with more health information integration being encouraged by the US. Meanwhile, developing countries are still using film and paper files with no electronic integration or electronic medical records.  The critical problem in outbreak detection is that many diseases having global threat potential include the third world, which means that there is incomplete surveillance of the global population. So, if a disease begins to spread in a remote part of the third world, the database systems are not in place for collecting and analyzing that information. 
 
RAD-AID believes in radiology’s contribution to public health initiatives so that imaging data will become a major part of the public health system.  Imaging is now part of many medical decisions in developed countries and this data is a vast reservoir of information that we can use to assess the health of the population.  In the setting of pneumonia, the American Thoracic Society and Infectious Disease Society of America recommend that diagnosis be confirmed by chest radiograph (Am. J. Respir. Crit. Care Med., Volume 163, Number 7, June 2001, 1730-1754).  Given this strong role for imaging in diagnosis, the opportunity to enhance public health networks is significant. Imagine being able to know, on a daily basis, how many cancers or cases of tuberculosis are in one city.  Response times to disasters and epidemics would drop dramatically to make our system agile and effective for protecting the public.  RAD-AID is committed to this objective.