Discussion
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ALHEChapter16_Medical_Imaging_Informatics.pptxChapter 16: Medical Imaging Informatics
Robert Hoyt MD
John Grizzard MD
Learning Objectives
After reviewing the presentation, viewers should be able to:
Describe the history behind digital radiology and the creation of picture archiving and communication systems (PACS)
Itemize the benefits of digital radiology to clinicians, patients and hospitals
List the challenges facing the adoption of picture archiving and communication systems
Describe the difference between computed and digital radiology
Outline the field of medical imaging informatics
Describe new imaging technologies such as Web PACS and mobile imaging viewers
Definitions
Medical Imaging Informatics: “study and application of processes of information and communications technology for the acquisition, manipulation, analysis and distribution of medical image data”
Society for Imaging Informatics in Medicine (SIIM)
Picture Archiving and Communication Systems (PACS): medical imaging technology which provides economical storage of, and convenient access to, images from multiple modalities
Introduction
Medical Imaging Informatics:
Could belong to Biomedical informatics or Radiology
Study of imaging, acquisition, storage, interpretation and sharing to improve patient care
Imaging data moves throughout medical enterprise and interacts with EHRs, voice recognition dictation systems, computer-aided diagnosis software, health information organizations, etc.
Important to have knowledge of workflow, networks, security, data quality, hardware and software
Digital imaging
Started in the 1970s
First filmless hospital occurred in 1999
Transitioning to PACS
Similar to photography (film to digital)
Introduction of computed tomography, ultrasound, and magnetic resonance imaging that all became digital
Eliminated need for film processing and storage rooms
Images could be viewed at a remote location
Advantages: cost savings, storage, retrieval
Transition to Filmless Radiology
Extensive initial costs
Printing remained for referring physicians
Use of film scanners for digital viewing
Proprietary imaging formats
Later, DICOM (DICOM = Digital Imaging and Communications in Medicine) standard was created
Upgrade conventional radiology rooms for CT, ultrasound, and MRI for the digital world
Computer-based image archiving
Transition to Filmless Radiology
Integrate PACS with EHRs, hospital information systems (HISs) and radiology information systems (RISs)
Veterans Health Administration launched a teleradiology network in 2007 to provide radiology coverage to all of its regions
Faster processors, higher capacity disk drives, higher resolution monitors, more robust hospital information systems, better servers and faster network speeds were necessary for the change to digital imaging
Picture Archiving and Communication Systems (PACS)
Full PACS
Images are processed from ultrasonography (US), magnetic resonance imaging (MRI), positron emission tomography (PET), computed tomography (CT), routine radiography and endoscopy
Mini-PACS
More limited and processes images from only one or two modalities
PACS Key Components
PACS Key Components
Digital acquisition devices: sources of images, such as digital angiography, fluoroscopy, mammography, CT, MRI , ultrasound scanners
Network: ties PACS components together
Database server: high speed and robust central computer to process information
Archival server: responsible for storing images and enables short term (fast retrieval) and long term (slower retrieval) storage
Radiology Information system (RIS): system that maintains patient demographics, scheduling, billing information and interpretations
Workstation: software and hardware to access PACS and replaces standard light box or view box
Teleradiology: ability to remotely view images at a location distant from the site of origin
Types of Digital Detectors
Computed radiography (CR)
After x-ray exposure to a special cassette, a laser reader scans the image and converts it to a digital image. The image is erased on the cassette so it can be used repeatedly
Digital radiography (DR)
Does not require an intermediate step of laser scanning
Typical PACS Workflow
Patient is identified in hospital information system (HIS)
An order is created that is sent to the radiology information system (RIS) via an HL7 protocol
Orders will go to imaging device via the DICOM protocol
Image is created in DICOM format and sent to the PACS server
Images are stored in image archive
Radiologist is notified of a pending study
Study is then read at a computer workstation using high-resolution monitors and viewing software available from a variety of different vendors
Comparison can be made to prior studies
Diagnostic report is generated by the radiologist, often using voice recognition software
Report is then stored on the PACS server
Web Based PACS
Reduce need for duplicate studies, and allow more rapid diagnosis and treatment
DICOM imaging format could be an impediment to use of the World Wide Web
Not browser compatible: Usually this entails downloading a small application (thin client) from the PACS vendor that enables the remote viewing station to act like a modified PACS workstation
Alternate potential solution: "zero-footprint" Web viewer where DICOM images are pre-converted to GIF
Legacy PACS compared to Web PACS in next slide
| Legacy PACS | Web PACS |
| Only available on computers with proper software installed | Available anywhere with internet access |
| Upgrades must be manually installed | Upgrades are done centrally or are not necessary |
| Multiple user interfaces | One user interface |
| Difficult to integrate with health information exchanges | Easy to integrate with health information exchanges |
| Difficult to link to multiple EHRs | Easier to link to EHRs |
| Labor intensive for PACS administrator for maintenance and training | Much less labor intensive for maintenance and training |
| Could involve multiple operating systems | One operating system |
| Less likely to be standards-based | Utilizes JPEG compression, DICOM, HL7 and IHE profiles |
Legacy vs. Web PACS
PACS and Mobile Technology
Until 2011, FDA prohibited physicians from using radiology images displayed on mobile devices to make an official diagnoses
Mobile MIM: Includes a VueMe version for patients
ResolutionMD Mobile is a medical imaging diagnostic application for radiologists. Their server-based software application allows physicians immediate access to the display, reports, and analysis of patient images such as CT and MR, stored within any healthcare facility, and to submit a clinical diagnosis via their medical devices
OsiriX Mobile DICOM Viewer is a free PACS open source viewer for the MAC operating system
PACS for a Hospital Desktop Features
Zoom-in feature for close-up detail
Ability to rotate images in any direction
Text button to see the report
Mark-up tool that does the following to the image: Adds text, measures the size and ratios of objects
Measures angles
Measures the square area of a mass or region
Adds an arrow
Right click on the image and short cut tools appear
Export an image to any of the following destinations: Teaching file,
CD-ROM, hard drive, USB drive, save to clipboard or Create a video
PACS Advantages
Replaces a standard x-ray film archive
Allows for remote viewing and reporting
Expedites the incorporation of medical images into an electronic health record
Images can be archived and transported on portable media, e.g. USB drive and Apple’s iPhone
Other specialties that generate images may join PACS such as cardiologists
PACS can be web-based and use “service oriented architecture”
Unlike conventional x-rays, digital films have a zoom feature and can be manipulated in innumerable ways
Improves productivity by allowing multiple clinicians to view the same image from different locations
Rapid retrieval of digital images for interpretation and comparison with previous studies
PACS Advantages
Fewer “lost films”
Reports are more likely to accompany the digital image
Radiologists can view an image back and forth like a movie, known as “stack mode”
Quicker reporting back to the requesting clinician
Digital imaging allows for computer aided detection (CAD)
Increased productivity
PACS Disadvantages
Cost: Open source and “rental PACS” are alternatives
New legislation cutting reimbursement rates
Expense and complexity to integrate with hospital and radiology information systems and EHRs
Lack of interoperability with other PACSs
Bandwidth limits may require network upgrades
Different vendors may use different DICOM tags to label films
Viewing digital images a little slower than routine x-ray films
Workstations may require upgrades if high resolution monitors are necessary
Moving Forward
Stage 2 Meaningful Use required both eligible professionals and hospitals to incorporate (or make accessible) through their electronic health records more than 10% of images ordered
Trend towards web based PACS
PACS is greatly accepted by clinicians
Fellowship in imaging informatics
Certificate in imaging informatics. Requirements can be found in the textbook
Imaging Informatics Education
PACS is the logical progression from x-ray films to digital imaging due to multiple new technologies
Medical Imaging Informatics will study the impact and significance of all facets of digital imaging
PACS is very popular among clinicians, patients and hospitals, but cost remains an issue
Web PACS offers more image interoperability options
Conclusions
