1. Applicability
This guidance is applicable to picture archiving and communications
systems (PACS). PACS are systems which are intended to provide transmission,
storage and viewing facilities for medical diagnostic images at distributed
locations. Some PACS are intended to transmit information over long distances
using public phone lines (e.g. teleradiology systems). Others are intended to
transmit images within a clinical facility by means of local area networks
(LANs).
The guidance is also applicable to related devices which perform one or
more of the functions (e.g. image transmission, storage or viewing) which may
be provided in a PACS. Such devices include:
image digitizers - video and film digitizers
image communications equipment - networks and interfaces
image storage devices - video recorders and digital storage media
workstations and their components - video monitors, image processors,
and image processing software
image hardcopy devices - laser printers and multiformat cameras
The guidance does not apply to general purpose devices if they are not
specifically indicated or promoted for use in conjunction with medical images.
These products are not considered to be medical devices and premarket
notifications are not required. Examples of such devices include general
purpose communications systems, data storage media and software. However, if
general purpose devices are indicated or promoted for medical use, a 510(k)
must be submitted. Also, if they are sold as a PACS component, they must be
described in the 510(k) for the system.
2. Update for Devices Employing Lossy
Compression
Data compression techniques have been utilized for medical image data
communication and storage for a number of years as a means of reducing
transmission time and storage requirements. However, recently there has been a
marked increase in the number of PACS devices which utilize lossy data
compression, i.e. compression techniques which do not preserve the original
data. This increase in activity has been reflected in the number of 510(k)
submissions for devices which incorporate lossy compression as a feature.
In response to these changes the Center has reconsidered the regulatory
issues associated with lossy compression. In particular, consideration has
been given to the suitability of lossy compression for different medical
applications such as primary diagnosis, referral and archiving. Consideration
has also been given to user needs with regard to promotional material, image
labeling and instructions. Related technical issues have also been considered.
These include the descriptive technical information to be included in the
submission, and the laboratory data and clinical studies which may be required
to support a finding of substantial equivalence.
In this document the original Draft Guidance dated 02-91 regarding the
content and review of PACS products has been revised to reflect these
considerations.
3. Content of Notification
The following information should be included in the 510(k):
3.1 General Information
a. Name and address of manufacturer
b. Establishment registration number
c. Common and proprietary names of the device
d. Class
No formal classifications have been issued for PACS or PACS
components. For purposes of determining substantial equivalence
they have been considered to be accessories to medical imaging
devices.
e. Applicable standards
The following standards should be referenced where applicable, and
a statement of compliance or noncompliance provided:
i. Food, Drug and Cosmetic Act -
No performance standards for PACS systems or components have
been issued under the authority of section 514.
ii. Radiation Control for Health and Safety Act -
Video monitors are considered to be television receivers and
subject to the performance requirements of 21 CFR 1020.10.
Fiberoptic communications, laser digitizers, laser printers
and optical disc storage devices utilize lasers, which are
subject to the performance requirements of 21 CFR 1040.10.
Note: Manufacturers must submit initial reports for video
monitors and laser products (21 CFR 1002.10). Reviewers
should ask manufacturers if they are aware of this
requirement.
iii. Voluntary Standards -
The Society of Motion Picture and Television Engineers
(SMPTE) has a standard test pattern for the evaluation of
television monitors and film recording cameras used in
medical diagnostic imaging.
The National Electrical Manufacturers Association (NEMA) and
American College of Radiology (ACR) have developed the
Digital Imaging and Communications Standard which is intended
to provided a standard method of data exchange.
The ACR/NEMA Data Compression Standard is intended to allow
the transmission of compressed image data across the
interface specified in the ACR/NEMA Digital Imaging and
Communications Standard. This standard is currently a draft.
The Underwriters Laboratories (U.L.) Standard No. 544 for
Medical and Dental Equipment contains safety requirements
which are applicable to PACS and PACS-related devices.
Reference may also be made to the draft standard ISO/IEC
10918-1 Digital Compression and Coding of Continuous-Tone
Still Images (also known as JPEG).
3.2 Device Description
a. Summary of functions of the device and its major components:
An overall summary of the functions of the device and its
indications for use should be provided. For devices comprised of
more than one major component, the summary should list these
components with a brief description of their individual functions.
In cases where a major component is obtained from another
manufacturer, the manufacturer and tradename should be given.
PACS devices which incorporate lossy compression will not be
required to restrict indications for use. However, manufacturers
may voluntarily restrict recommended use either in general or
specific terms (e.g. not for primary diagnosis, not for use in
conjunction with mammography images, etc.).
b. Diagram of layout and interconnections:
For devices comprised of more than one major component, an overall
diagram illustrating their interconnection should be provided.
Interfaces (e.g. ACR/NEMA, SCSI, etc.) should be labeled. Also,
the physical means utilized for the interchange of data (e.g.
twisted pair, coaxial cable, fiberoptic cable, etc.) should be
identified. Interconnections which transmit compressed data should
be specifically labeled along with the compression ratio.
c. Technical characteristics and means of operation:
The means utilized by each major component to perform its function
should be described. A list of all operator controls with a brief
description of their functions should be included. Any new
technology or unique materials which are utilized should be
identified. For devices which utilize new technology or materials,
copies of related technical publications should be submitted.
The following information should be included for specific types of
PACS-related devices. If the 510(k) is for a complete system, this
information should be submitted for each device in the system.
i. Image digitizers -
All devices - The method used to digitize the image (e.g.
video camera and ADC, solid state sensor or laser scanner)
should be described. Also, a diagram illustrating the optical
path indicating the positions of all major optical,
mechanical and electronic components should be provided.
Film digitizers - The method and equipment used to scan the
film should be discussed, and a diagram illustrating the
major components of the scanning mechanism should be
included.
ii. Communications and image storage devices -
Communications - In cases where standard, general purpose
equipment is utilized it is only necessary to provide the
manufacturer, tradename and a brief description. For new
types of equipment the topology, access control methods and
methods used for detecting transmission errors should be
discussed.
Storage - In cases where standard, general purpose equipment
is utilized, it is only necessary to provide the
manufacturer, tradename, form of storage (analog or digital),
and type of storage medium (e.g. solid state, floppy or hard
disc, magnetic tape, optical disc). For new types of
equipment, the new technology should be discussed in detail
and copies of related technical literature provided.
Image formats - The manufacturer should identify any other
manufacturers with whom he has or intends to make
arrangements to obtain their image data formats.
Data compression - If standard data compression schemes (e.g.
differential pulse code modulation (DPCM), Huffman encoding)
are utilized in communications or storage, they may be
identified by name. If non-standard or proprietary methods
are employed, the algorithms utilized should be described in
detail and copies of any related technical publications
provided.
iii. Workstations -
Monitors - The monitor types (black and white or color,
progressive or interlaced) and available image display
formats (e.g. 2-on-1, 4-on-one) should be listed. Video
monitor diagnostics provided by the software (e.g. SMPTE test
pattern) should be identified or described.
Processors and storage - The image processing hardware should
be listed along with the basic function of each device (e.g.
host computer, additional processors and their functions).
Image storage media provided with the workstation should be
listed (e.g. floppy and hard discs, magnetic tape, optical
disc, RAM, etc.).
Operator Interfaces - Keyboards and other controls (e.g.
mouse, trackball) should be listed and any special purpose
digitizers (e.g. 3D) should be described.
Software - All software image processing algorithms (e.g.
filters and image enhancement techniques) should be listed
along with their basic function. In cases where standard 3
dimensional reconstruction and display are provided, the
algorithms (e.g. surface and volume rendering) should be
identified. If new algorithms are used, copies of related
technical references should be provided. In cases where
quantitative algorithms are included in the software (e.g.
cardiac function algorithms), the method of measurement
should be described. Also, if new quantitative algorithms are
used, the results of any clinical studies and copies of
publications in the technical literature supporting the
validity of the algorithms should be provided.
iv. Hardcopy devices -
All devices - For all types of hardcopy devices (film, paper,
etc.), the form of input (i.e. video and/or digital input
signals) should be listed. A diagram illustrating the optical
path indicating the positions of all major optical,
mechanical and electronic components should be provided. The
means for adjusting the grey scale of the image (gamma
corrections) should be described. Any internal calibration
test patterns should be discussed. If an integral hardcopy
medium processor is provided it should be described. The
method for handling the hardcopy medium (e.g. cassette)
should also be discussed.
Multiformat cameras - For multiformat cameras, the video
monitor should be described, and the manufacturer should
state if raster line suppression or image contrast inversion
are provided. The number of lenses used and the mechanism
(optical, mechanical or electronic) used to advance to the
next position should be discussed.
Laser printers - For laser printers, the type of laser (e.g.
HeNe, solid state) should be stated and the sensitivity of
the hardcopy medium relative to the wavelength of the laser
should be discussed. The methods of modulating the laser and
scanning the beam over the hardcopy medium should be
described.
d. Specifications:
The following specifications should be included for specific types
of PACS-related devices. If the 510(k) is for a complete system,
specifications should be submitted for each device in the system.
i. Image digitizers -
Video to digital - compatible video signals (lines/frame,
frames/sec, progressive or interlaced), digital sampling rate
and bit depth
Film digitizers - film size, matrix size and bit depth,
spatial resolution, time to scan an image (specify matrix
size). For laser digitizers, laser spot size and power.
ii. Communications and storage equipment -
Communications equipment - bits/sec and time to transmit an
image (specify matrix size and bit depth)
Video recorders - compatible video signals (lines/frame,
frames/sec, progressive or interlaced), bandwidth, tape size
and speed, signal-to-noise ratio and total recording time
Digital storage devices - total number of bits, image matrix
sizes, bit depth and number of images
iii. Workstations -
Video monitors - compatible video signals (lines/frame,
frames/sec, progressive or interlaced), horizontal resolution
or bandwidth, aspect ratio and screen size
Image processing hardware - clock rate and number of
bits/word, time to perform major software operations such as
tomographic image reconstruction, multiplanar reconstruction
and 3 dimensional rendering
Digital storage devices - total number of bits, image matrix
sizes, bit depth and number of images (specify matrix size)
iv. Hardcopy devices -
All types - compatible digital input (matrix size and bit
depth), compatible video input (lines/frame, frames/sec,
progressive or interlaced), hardcopy image sizes and formats
Multiformat cameras - monitor vertical and horizontal
resolution or bandwidth, aspect ratio and screen size
Laser printers - matrix size, bit depth, spatial resolution,
laser spot size and power, time to produce an image (state
matrix size)
3.3 Laboratory Tests
The following laboratory tests should be conducted for specific types of
PACS-related devices. Manufacturers should include a brief description of
their test methods and results in the 510(k). If the 510(k) is for a complete
system, test methods and results should be submitted for each device in the
system.
a. Image digitizers -
For devices which claim new or significantly improved digitizing
hardware, the optical density (OD) to grey level tranfer curve,
uniformity (local standard deviation of OD vs. OD) and spatial
frequency response (modulation transfer function)
b. Communications and storage devices -
For devices which utilize compression techniques which result in a
loss of image data, the normalized mean square error of the
compressed image relative to the original.
When providing laboratory test data for a lossy compression scheme
a manufacturer may substitute an alternative measure of
information loss for normalized mean square error, if a
description and justification are provided.
For devices which utilize standard lossy compression techniques,
such as Discrete Cosine Transform (DCT) laboratory data is not
required.
c. Hardcopy devices -
For devices which claim new or significantly improved hardware to
produce the image, the grey level to OD tranfer curve, uniformity
(local standard deviation of OD vs. OD) and spatial frequency
response (modulation transfer function).
3.4 Substantially Equivalent (SE) Devices
a. Manufacturer and tradename of SE devices
All SE devices must have approved 510(k) notifications or be
pre-amendments devices. Pre-Amendments devices should be
identified. Document control numbers should be provided for
post-Amendments devices if the control numbers are available.
b. Promotional material and specifications for SE devices (see
section 2.2(e) above)
c. Tabular comparison of features and specifications of the device
and SE devices
3.5 Labeling
a. Promotional material (drafts are acceptable)
Promotional material for devices which utilize lossy compression
shall clearly state the compression ratios provided.
b. User's manual(s) (drafts are acceptable) including:
i. Any special intended uses (e.g. cardiac cath lab)
ii. Cautions and warnings (radiation, laser, electrical, etc.)
iii. Applicable specifications listed in section 2.2(e) above
iv. Operating instructions
These should describe any loss of information associated with
image processing functions (filters) or image data
compression operations.
Devices which utilize lossy compression shall be provided
with instructions which explain the effects of lossy
compression, and include examples of the effects of
information loss on image quality.
v. Quality assurance procedures
Built-in component diagnostics, test patterns or recommended
procedures
c. Images
Video and hardcopy images which have been subjected to lossy
compression shall be provided with a printed message stating that
lossy compression has been applied, and the approximate
compression ratio.
3.6 Software Information
a. A list and brief description of the functions performed by the
software
b. A description of the manufacturer's software development methods
This should include a list or diagram of the steps in the
development of the software and the departments responsible for
each step. Procedures for controlling the software version during
development and after release should be addressed.
c. A list of hazards related to the functions performed by the
software, and means taken to mitigate these hazards
Such hazards may include loss or corruption of image data, patient
ID, or information describing the examination.
d. A description of the software test procedures
e. A certification by a responsible company official that the
software information provided in this notification is correct, and
that the same procedures will be used to retest and revalidate the
software when it is revised.
3.7 Safety and Effectiveness Information
The Safe Medical Devices Act of 1990 (SMDA) requires all persons
submitting a premarket notification to include either:
(1) a summary of the safety and effectiveness information in the
premarket notification submission upon which an equivalence
determination could be based (510(k) summary), or
(2) a statement that the safety and effectiveness information upon
which an equivalence determination could be based will be made
available to interested persons upon request (510(k) statement).
Safety and effectiveness information refers to information in the
notification, including adverse safety and effectiveness information,
that is relevant to an assessment of substantial equivalence. The
information could be descriptive information about the new and
predicate device(s), or performance or clinical testing information.
Note:
The SMDA allows the manufacturer to submit a 510(k) summary with the
premarket notification, or a 510(k) statement which affirms that the
safety and effectiveness information will be submitted upon request.
If the 510(k) statement is submitted, the wording must follow that
given above. A statement which reads "a summary of the safety and
effectiveness information will be made available" is not acceptable.
(This document was still considered current as of July 1996. It will be reviewed again in July 1997.)