<span dir="rtl">Medical Imaging Informatics (معلوماتية التصوير الطبي)</span>

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Nov 5, 2013 (3 years and 7 months ago)

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Medical Imaging Informatics
(
يبطلا ريوصتلا ةيتامولعم
)


(PACS)


Picture archive communication system (PACS)


design and implementation


clinical PACS
-
based imaging informatics


History


The principles of PACS were first discussed at
meetings of radiologists in 1982. Various
people are credited with the coinage of the
term

PACS
. Cardiovascular radiologist Dr
Andre
Duerinckx

reported in 1983 that he had
first used the term in 1981.
[4]

Dr Samuel
Dwyer, though, credits Dr Judith M. Prewitt for
introducing the term.
[5]



telemedicine/
tele
-
radiology


image content indexing, image data mining


grid computing in large
-
scale imaging
informatics


image
-
assisted diagnosis, surgery and therapy


Radiology information system


A

radiology information system

(RIS) is a
computerized

database

used
by

radiology

departments to store, manipulate,
and distribute patient radiological data and
imagery. The system generally consists of

patient
tracking

and scheduling, result reporting and
image tracking capabilities. RIS complements

HIS
(Hospital Information Systems)
, and is critical to
efficient workflow to radiology practices


Radiology information systems commonly
support the following features:


Patient Registration and scheduling


Patient List Management


Interface with modality via
Worklist
.


Radiology Department workflow management


Request and document scanning


Result(s) Entry



Reporting and printout


Result(s) Delivery including faxing and e
-
mailing of clinical reports


Patient Tracking


Interactive Documents


Technical Files Creation


Modality and Material management.



The first large
-
scale PACS installation was in
1982 at the University of Kansas, Kansas
City.
[2]

This first installation became more of a
teaching experience of what not to do rather
than what to do in a PACS installation.



Regulatory concerns


In the US PACS are classified as Medical Devices, and hence
if for sale are regulated by the

USFDA
. In general they are
subject to Class 2 controls and hence require a

510(k)
,
though individual PACS components may be subject to less
stringent general controls.
[7]

Some specific applications,
such as the use for primary mammography interpretation,
are additionally regulated
[8]

within the scope of
the

Mammography Quality Standards Act
.


The Society for Imaging Informatics in Medicine (SIIM) is
the worldwide professional and trade organization that
provides an annual meeting and a peer
-
reviewed journal to
promote research and education about PACS and related
digital topics.


In addition a RIS often supports the following:


Appointment booking


PACS workflow


Custom report creation


HL7

interfaces with a

PACS
. HL7 also enables
communication between HIS and RIS in
addition to RIS and PACS.


electronic patient record


eMix


Filmless image technology


hospital information system


picture archiving and communication system
"PACS"


Medical imaging


Medical software

Benefits


Reduce Errors and Enhance Patient Care


Prevents manual data entry errors by ensuring
that a particular piece of data is entered only
once


Prevents complications from patient allergies or
pregnancy status since these details are made
available to all systems involved in the radiology
workflow


Prevents delays in patient care by making
relevant information available at the point of care


Improve Throughput


Saves manual data entry time by ensuring that
a particular piece of data is entered only once


Minimizes "lost" studies by ensuring study
identification and status is accurately tracked
throughout the department.


Reduces staff time wasted identifying and
correcting errors (in a coordinated fashion)
among the HIS, RIS, PACS and modality



A

picture archiving and communication
system

(
PACS
) is a

medical imaging

technology
which provides economical storage of, and
convenient access to, images from multiple
modalities (source machine
types).
[1]

Electronic images

and reports are
transmitted digitally via PACS; this eliminates
the need to manually file, retrieve, or
transport film jackets


The universal format for PACS image storage
and transfer is

DICOM (Digital Imaging and
Communications in Medicine)
. Non
-
image
data, such as

scanned

documents, may be
incorporated using consumer industry
standard formats like

PDF (Portable Document
Format)
, once encapsulated in DICOM. A PACS
consists of four major components


The imaging modalities such as

X
-
ray
computed tomography

(CT) and

magnetic
resonance imaging

(MRI), a
secured

network
for

the transmission of
patient information,

workstations

for
interpreting and reviewing images, and
archives for the

storage

and retrieval of
images and reports.


Combined with available and
emerging

web

technology, PACS has the ability
to deliver timely and efficient access to
images, interpretations, and related data.
PACS breaks down the physical and time
barriers associated with traditional

film
-
based

image retrieval, distribution, and
display.

Types of images


Most PACSs handle images from various medical
imaging instruments, including

ultrasound
(US)
,

magnetic resonance (MR)
,

positron emission
tomography (PET)
,

computed tomography
(CT)
,

endoscopy (ES)
,

mammograms (MG)
,

Digital
radiography (DR)
,

computed radiography
(CR)

ophthalmology, etc. Additional types of image
formats are always being added. Clinical areas beyond
radiology; cardiology, oncology, gastroenterology and
even the laboratory are creating medical images that
can be incorporated into PACS. (see

DICOM Application
areas
).


PACS has four main uses:


Hard copy replacement: PACS replaces

hard
-
copy

based means of managing medical
images, such as film archives. With the
decreasing price of digital storage, PACSs
provide a growing cost and space advantage
over film archives in addition to the instant
access to prior images at the same institution.
Digital copies are referred to as Soft
-
copy.


Remote access: It expands on the possibilities
of conventional systems by providing
capabilities of off
-
site viewing and reporting
(
distance education
,

telediagnosis
). It enables
practitioners in different physical locations to
access the same information simultaneously
for

teleradiology
.


Electronic image integration platform: PACS
provides the electronic platform for radiology
images interfacing with other medical
automation systems such as

Hospital
Information System

(HIS),

Electronic Medical
Record

(EMR),

Practice Management
Software
, and

Radiology Information
System

(RIS).



PACS workflow diagram


The architecture is the physical implementation
of required functionality, or what one sees from
the outside. There are different views, depending
on the user. A radiologist typically sees a viewing
station, a technologist a QA workstation, while a
PACS administrator might spend most of their
time in the climate
-
controlled computer room.
The composite view is rather different for the
various vendors


Typically a PACS consists of a multitude of
devices. The first step in typical PACS systems
is the modality. Modalities are typically
computed tomography (CT), ultrasound,
nuclear medicine, positron emission
tomography (PET), and magnetic resonance
imaging (MRI).


Depending on the facility's workflow most
modalities send to a quality assurance (QA)
workstation or sometimes called a PACS
gateway. The QA workstation is a checkpoint
to make sure patient demographics are
correct as well as other important attributes
of a study. If the study information is correct
the images are passed to the archive for
storage.


The next step in the PACS workflow is the
reading workstations. The reading workstation
is where the radiologist reviews the patient's
study and formulates their diagnosis.
Normally tied to the reading workstation is a
reporting package that assists the radiologist
with dictating the final report.


Reporting software is optional and there are
various ways in which doctors prefer to dictate
their report. Ancillary to the workflow
mentioned, there is normally CD/DVD authoring
software used to burn patient studies for
distribution to patients or referring physicians.
The diagram above shows a typical workflow in
most imaging centers and hospitals. Note that
this section does not cover integration to a
Radiology Information System, Hospital
Information System and other such front
-
end
system that relates to the PACS workflow.



More and more PACS include web
-
based
interfaces to utilize the internet or a

Wide Area
Network

as their means of communication,
usually via

VPN

(Virtual Private Network)
or
SSL

(Secure Sockets Layer). The client side
software may use

ActiveX
,

JavaScript

and/or
a

Java Applet
. More robust PACS clients are full
applications which can utilize the full resources of
the computer they are executing on and are
unaffected by the frequent unattended

Web
Browser

and Java updates.


As the need for distribution of images and
reports become more widespread there is a push
for PACS systems to support DICOM part
18
of
the DICOM standard. Web Access to DICOM
Objects (WADO) creates the necessary standard
to expose images and reports over the web
through truly portable medium. Without stepping
outside the focus of the PACS architecture, WADO
becomes the solution to cross platform capability
and can increase the distribution of images and
reports to referring physicians and patients.



PACS image backup is a critical, but sometimes
overlooked, part of the PACS Architecture (see
below).

HIPAA

requires that backup copies of
patient images be made in case of image loss
from the PACS. There are several methods of
backing up the images, but they typically
involve automatically sending copies of the
images to a separate computer for storage,
preferably off
-
site.


Querying (C
-
FIND) and Image Retrieval (C
-
MOVE)


The communication with the PACS server is done
through
dicom

objects that are similar to
dicom

images, but with different attributes. A query typically
looks as follows:


The client establishes the network connection to the
PACS server.


The client prepares a query object which is an empty
dicom

dataset object.


The client fills in the query object with the keys that
should be matched. E.g. to query for a patient ID, the
patient ID attribute is filled with the patient's ID.



Images are retrieved from a PACS server through
a C
-
MOVE request, as defined by the DICOM
network protocol. This request specifies where an
image instance should be sent through an
identifier known as the destination Application
Entity Title (AE Title). The server must be
configured with mapping of the AE Title to a
TCP/IP address and port, and as a consequence
the server must know in advance all the AE Titles
that it will ever be requested to send images to.



Typically a radiologist is looking for prior studies
on a patient to compare the progression of some
pathology. In some cases prior studies may be on
an off
-
site archive or a long term storage device.
In the example being used, the radiologist or
radiology technical must query the off
-
site or
long term archive for the prior exam(s). The
archive receives the C
-
FIND and if the C
-
FIND is
successful the archive invokes a C
-
MOVE on the
study to the called AE Title, in
-
turn sending the
study from the archive to the device requesting
the study.


]
References


^

Choplin
, R., (1992). Picture archiving and communication
systems: an overview.
Radiographics

January 1992 12:127
-
129


^

a

b

Oosterwijk
, Herman. PACS Fundamentals. Aubrey:
OTech

Inc, 2004.

ISBN 978
-
0
-
9718867
-
3
-
5


^

HealthcareITnews
: HHS cracks down: provider to pay
$100,000 in HIPAA penalties over lost laptops. July 17,
2008, Diana Manos, Senior Editor


^

Duerinckx

AJ, Pisa EJ. Filmless Picture Archiving and
Communication System (PACS) in Diagnostic Radiology.
Proc SPIE 1982;318;9
-
18. Reprinted in IEEE Computer
Society Proceedings of PACS'82, order No 388.


^

Samuel J. Dwyer III. A personalized view of the
history of PACS in the USA. In:

Proceedings of the SPIE
,
"Medical Imaging 2000: PACS Design and Evaluation:
Engineering and Clinical Issues", edited by G. James
Blaine and Eliot L. Siegel. 2000;3980:2
-
9.


^

Bryan S,
Weatherburn

GC, Watkins JR, Buxton MJ
(1999). "The benefits of hospital
-
wide picture
archiving and communication systems: a survey of
clinical users of radiology
services".
Br

J
Radiol

72

(857): 469

78.

PMID

10505012
.


^

USFDA

(27 July 2000).

"Guidance for the Submission
Of Premarket Notifications for Medical Image
Management Devices"
. Retrieved 11 February 2010.