DICOM

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DICOM

• Kelly Welch

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DICOM

• Digital Imaging and Communications in Medicine
  (DICOM)
• Many imaging systems use different computer
  platforms and the data can be acquired using
  different modalities.
• Therefore hospitals needed a standard for
  integrating all these into an organized system.
• ? This standard is DICOM

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HISTORY

• American College of Radiology (ACR) and the
  National Electrical Manufactures Association
  (NEMA) decided to form a committee to create a
  standard in 1983.
• First version in 1985 titled Version 1.0

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The standard evolves

• Because of the increases in technology the
  standard needed to be updated.
• Version 2.0 released in 1988
• This was a compilation between Version 1.0 and
  the additions that needed to be added.

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The standard evolves

• In 1993, the latest version, called Version 3.0
  was released.
• Many amendments and additions have been made to
  this Version since then.
• The new 2004 release is expected to be out next
  month.

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What is DICOM composed of?

• The DICOM Information File is made up of many
  different Attributes.
• Example
• Pixel Data Body Part Imaged
• Study Date Physician
• Patient Name

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Attribute Tags

• Each tag consists of Group Number followed by an
  Element Number.
• Example Patients ID (0010, 0020)
• 0010 is the tag for the Group Number
• 0020 is the tag for the Element Number
• There is a specific tag for each Attribute, for
  any real-world variable.

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Hierarchical System

• The tags are arranged in a hierarchical system
• PATIENT
• STUDY
• SERIES
• IMAGE
• Each variable has an Unique Identifier (UID)
  associated with it.

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Types

• There are Types for the tags which specify
  whether they must be included in the DICOM file.
• Type 1 Required
• Type 2 Optional
• Type 3 Required only for certain cases

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Strings

• These tags are encoded in unique 16 bit strings.
• Example
• 1.2.840.xxxxx.3.152.348.2.28.189436474

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1.2.840.xxxxx.3.152.348.2.28.189436474

• 1 Identifies the International Standards
  Organization (ISO)
• 2 Identifies ANSI Member Body
• 840 Country code of specific Member Body (US
  for ANSI)
• xxxxx Number that Identifies a specific
  Organization

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1.2.840.xxxxx.3.152.348.2.28.189436474

• 3 Manufacture or user defined device type (ex
  CT)
• 152 Manufacturer or user defined serial number

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1.2.840.xxxxx.3.152.348.2.28.189436474

• 348 Unique Study Number
• 2 Unique Series Number
• 28 Unique Image Number
• 18946474 - The encoded data and time stamp
  of the image at the point of acquisition

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How is a DICOM Image created?

• DICOM sets the standard for what image data must
  be included in a DICOM file.
• The specific program that views the image parses
  the DICOM file and extracts the needed image
  information.
• Because image data is of Type 1 there is an
  assurance that the data will be available.

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Advantages

• COMPATIBILITY It sets the criteria for the way
  in which medical image data is obtained and
  stored across platforms.
• INTERCONNECTIVITY Data for images can be
  exchanged easily between competing vendors.
• REALIABLE Digital data storage has a lower loss
  of resolution when displayed than analogue
  storage did previously.

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Disadvantages

• It has been discovered that some of the Attribute
  fields are often missing or empty, creating a
  problem between vendors.
• Multi-dimensional standards have yet to be
  implemented properly.

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Future of DICOM amendments

• DICOMDIR (DICOM Directory)
• Specifies how the DICOM information is to be
  arranged on a duplicated CD such that any other
  image viewing system might be able to extract the
  needed image data with ease and certainty.
• Results in faster parsing of the information.

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Future of DICOM amendments

• Structured Reporting
• Defines the structure of the medical reports that
  are included in a CD given out to patients or
  referring physicians.
• Some implemented, new additions for
• Ultrasound OB-GYN
• Vascular Ultrasound
• Echocardiography
• Breast Imaging

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Conclusion

• Indispensable component for the integration of
  digital imaging systems in the field of medicine.
• Conflicting modalities are able to attain a
  higher communication and compatibility both now
  and in the future.
• Constant amendments by the committee assure that
  the standard is up-to-date on all the
  advancements in the medical industry.