Pacs fundamentals

Elsevier items and derived items © 2008 by Mosby, Inc., an affiliate of Elsevier Inc. 1
PACS FundamentalsPACS Fundamentals

ObjectivesObjectives
 Define picture archiving and communication systemsDefine picture archiving and communication systems
(PACS).(PACS).
 Compare and contrast the various types of PACSCompare and contrast the various types of PACS
display workstations.display workstations.
 Differentiate between the different types of digitalDifferentiate between the different types of digital
imaging workflow.imaging workflow.
 Define system architecture and recognize the threeDefine system architecture and recognize the three
major models.major models.
 Summarize the common functions found on a PACSSummarize the common functions found on a PACS
workstation.workstation.
 Describe the situations and users that might useDescribe the situations and users that might use
advanced PACS workstation functions.advanced PACS workstation functions.

Key TermsKey Terms
 ArchiveArchive
 Client/server-basedClient/server-based
systemsystem
 DICOMDICOM
 Display workstationDisplay workstation
 Distributed systemDistributed system
 File room workstationFile room workstation
 Hanging protocolHanging protocol
 Navigation functionsNavigation functions
 PACSPACS
 QC stationQC station
 Reading stationReading station
 Review stationReview station
 Soft copySoft copy
 System architectureSystem architecture
 TeleradiologyTeleradiology
 Web-based systemWeb-based system
 WorkflowWorkflow

IntroductionIntroduction
 PACSPACS
 PicturePicture
 ArchivingArchiving
 CommunicationCommunication
 SystemsSystems

FundamentalsFundamentals
 PACS consists of the following:PACS consists of the following:
 Digital acquisition (Picture)Digital acquisition (Picture)
 Display workstationsDisplay workstations
 Storage devices (Archiving)Storage devices (Archiving)
 Components are interconnected through an intricateComponents are interconnected through an intricate
network. (Communication)network. (Communication)
 PACS is the electronic version of the radiologist’sPACS is the electronic version of the radiologist’s
reading room and the file room.reading room and the file room.

Typical PACS DesignTypical PACS Design

FundamentalsFundamentals
 First PACSFirst PACS
• Early 1980sEarly 1980s
• Served one single modalityServed one single modality
• Large research institutionsLarge research institutions
• Most developed by scientists in those institutionsMost developed by scientists in those institutions
 LaterLater
• Vendors became more involved.Vendors became more involved.
• Proprietary systems were developed.Proprietary systems were developed.
 StandardizationStandardization

DICOMDICOM
 First version was completed inFirst version was completed in
1985.1985.
 DICOMDICOM
 Digital imaging andDigital imaging and
communications in medicine.communications in medicine.
• Universally accepted standardUniversally accepted standard
• Laid the groundwork for theLaid the groundwork for the
future development of integratedfuture development of integrated
PACSs.PACSs.
• Now every modality and PACSNow every modality and PACS
communicates via DICOM.communicates via DICOM.
• Each vendor and modalityEach vendor and modality
boasts DICOM compatibility.boasts DICOM compatibility.
 Each DICOM statement mustEach DICOM statement must
be read carefully to determinebe read carefully to determine
the extent of the compatibility.the extent of the compatibility. http://medical.nema.org/

ComponentsComponents
 PACS can be broken into three fundamental parts:PACS can be broken into three fundamental parts:
 Image acquisitionImage acquisition
 Display workstationsDisplay workstations
 Archive serversArchive servers

Image AcquisitionImage Acquisition
 Images are acquired in a digital format:Images are acquired in a digital format:
 UltrasoundUltrasound
• Early ultrasound mini-PACS networks became a norm inEarly ultrasound mini-PACS networks became a norm in
many hospitalsmany hospitals
 Computed Tomography (CT)Computed Tomography (CT)
• As the images sets increased in number, thisAs the images sets increased in number, this
necessitated the transition to soft-copy readingnecessitated the transition to soft-copy reading
 Magnetic Resonance Imaging (MRI)Magnetic Resonance Imaging (MRI)
• As with CT as the numbers of images increased, readingAs with CT as the numbers of images increased, reading
on a monitor became a good alternative.on a monitor became a good alternative.
 Nuclear medicineNuclear medicine
 Computed radiographyComputed radiography
 MammographyMammography

Display WorkstationsDisplay Workstations
 Display workstation is any computer used to view aDisplay workstation is any computer used to view a
digital image.digital image.
 Most interactive part of a PACS.Most interactive part of a PACS.
 Used inside and outside of the radiology department.Used inside and outside of the radiology department.

 Display station.Display station.
 Receives images from archive or various radiologyReceives images from archive or various radiology
modalitiesmodalities
 Presents images to be viewedPresents images to be viewed
 Workstation has some sort of PACS applicationWorkstation has some sort of PACS application
software.software.
 Some may have advanced software with additionalSome may have advanced software with additional
image processing capabilities.image processing capabilities.

Archive ServersArchive Servers
 File room of the PACSFile room of the PACS
 Consists of the following:Consists of the following:
 Database server or imageDatabase server or image
managermanager
 Short-term and long-term storageShort-term and long-term storage
 Workflow managerWorkflow manager
 Central part of the PACSCentral part of the PACS
 Houses all of the historic andHouses all of the historic and
current datacurrent data
 May also serve as theMay also serve as the
centralized node that receivescentralized node that receives
all images before interpretationall images before interpretation

WorkflowWorkflow
 WorkflowWorkflow
 How a process is done step by step or how a task isHow a process is done step by step or how a task is
completedcompleted
 How one completes an exam from order entry to transcribedHow one completes an exam from order entry to transcribed
reportreport
 Exact workflow different in every radiologyExact workflow different in every radiology
departmentdepartment

Generic WorkflowGeneric Workflow
 Digital is similar but still different from film-basedDigital is similar but still different from film-based
system.system.

System ArchitectureSystem Architecture
 American National Standards Institute andAmerican National Standards Institute and
the Institute of Electrical and Electronicsthe Institute of Electrical and Electronics
EngineersEngineers
 Definition of system architecture:Definition of system architecture:
• Basic organization of a system come to life in itsBasic organization of a system come to life in its
components, their associations to each other and thecomponents, their associations to each other and the
environment, and the principles leading its design andenvironment, and the principles leading its design and
developmentdevelopment

System ArchitectureSystem Architecture
 In other words,In other words,
 System architecture is the hardware and softwareSystem architecture is the hardware and software
infrastructure of the systems workflow.infrastructure of the systems workflow.
 In PACS the system architecture normally consists of theIn PACS the system architecture normally consists of the
following:following:
• Acquisition devicesAcquisition devices
• Storage and display workstationsStorage and display workstations
• Image management systemImage management system

PACS ArchitecturePACS Architecture
 Three common PACS architecturesThree common PACS architectures
 Client/server-basedClient/server-based
 Distributed systemsDistributed systems
 Web-based systemsWeb-based systems

Client/Server-Based SystemsClient/Server-Based Systems
 Images are sent to archiveImages are sent to archive
serverserver
 Display workstation functionsDisplay workstation functions
as a client of the archive serveras a client of the archive server
 Accesses images based on aAccesses images based on a
centralized worklist.centralized worklist.
 Person at the client chooses aPerson at the client chooses a
name from the list.name from the list.
 Archive server sends theArchive server sends the
image data to the client.image data to the client.
 The image data is only on theThe image data is only on the
client while viewing.client while viewing.
 Most systems allow basicMost systems allow basic
image manipulation at theimage manipulation at the
client.client.
 Changes are saved on theChanges are saved on the
archive server.archive server.

 Advantages:Advantages:
 Any exam sent to the PACS is available anywhereAny exam sent to the PACS is available anywhere
without other interventions.without other interventions.
 Only one person can open the study with theOnly one person can open the study with the
intent to read it. Others that open the studyintent to read it. Others that open the study
receive a message that the study is open andreceive a message that the study is open and
being read.being read.
 There is no need to pull or send historic images toThere is no need to pull or send historic images to
a particular workstation because the old studiesa particular workstation because the old studies
are available with the new on the archive.are available with the new on the archive.

 Disadvantages:Disadvantages:
 The archive server is seen as a single point ofThe archive server is seen as a single point of
failure.failure.
• If the archive goes down, the entire system is down andIf the archive goes down, the entire system is down and
no image movement can take place.no image movement can take place.
• Newly acquired images must remain at the modality untilNewly acquired images must remain at the modality until
the archive is up and can receive the images.the archive is up and can receive the images.
 System is network dependent.System is network dependent.
• Images are flying back and forth between the archiveImages are flying back and forth between the archive
and the workstations.and the workstations.
• Network can become bogged down.Network can become bogged down.
 Archive server is handling many requests at onceArchive server is handling many requests at once
and can become bottlenecked.and can become bottlenecked.

Distributed SystemsDistributed Systems
 Distributed systems are also known asDistributed systems are also known as distributeddistributed oror
stand-alone models.stand-alone models.
 Acquisition modalities send the images to aAcquisition modalities send the images to a
designated reading station and possibly todesignated reading station and possibly to reviewreview
stationsstations..
 In some systems the images are sent from theIn some systems the images are sent from the
modality to the archive server, and the archive servermodality to the archive server, and the archive server
distributes the images to the designated workstation.distributes the images to the designated workstation.

 Reading station designations may be designed onReading station designations may be designed on
radiologist’s reading preferences.radiologist’s reading preferences.
 Example:Example:
 MRI may send to one stationMRI may send to one station
 CT sends to anotherCT sends to another
 Or all cross-sectional neurologic images may be sent to oneOr all cross-sectional neurologic images may be sent to one
station, whereas all body imaging may be sent to anotherstation, whereas all body imaging may be sent to another
 Designation is decided after extensive workflowDesignation is decided after extensive workflow
observations.observations.

 Workstations can query and retrieve images from theWorkstations can query and retrieve images from the
archive.archive.
 All images are locally stored.All images are locally stored.
 Images are then sent to the archive server once theImages are then sent to the archive server once the
images have been read.images have been read.
 Images remain on local hard drive of workstation untilImages remain on local hard drive of workstation until
they are deleted by user or system rules.they are deleted by user or system rules.

 If the archive server goes down, local reading atIf the archive server goes down, local reading at
the workstations is not interrupted.the workstations is not interrupted.
• After archive comes back up, the images that have beenAfter archive comes back up, the images that have been
changed and signed off are automatically forwarded tochanged and signed off are automatically forwarded to
the archive to be saved.the archive to be saved.
 PACS data is less likely to be lost because ofPACS data is less likely to be lost because of
multiple copies in various locations.multiple copies in various locations.
 System is less dependent on network for speed.System is less dependent on network for speed.
• User can work on one exam while workstation is pullingUser can work on one exam while workstation is pulling
next exam to be read.next exam to be read.
• Workstation can fetch historic images based on rules setWorkstation can fetch historic images based on rules set
up by the user.up by the user.
• Fetching can be done while other exams are being read.Fetching can be done while other exams are being read.

 Personnel rely heavily on system to perform imagePersonnel rely heavily on system to perform image
distribution correctly.distribution correctly.
• If distribution is wrong, then prefetching of historic exams will beIf distribution is wrong, then prefetching of historic exams will be
wrong.wrong.
 Each workstation has a different worklist; only one person atEach workstation has a different worklist; only one person at
a time can work on that list.a time can work on that list.
 It can be inconvenient to read additional studies.It can be inconvenient to read additional studies.
• Radiologist would have to move to another workstation to readRadiologist would have to move to another workstation to read
the images.the images.
 Users must depend on query and retrieve function whenUsers must depend on query and retrieve function when
nonscheduled exams arrive at workstation.nonscheduled exams arrive at workstation.
 It is possible for two radiologists to be reading the sameIt is possible for two radiologists to be reading the same
exam and not know it until they try to start dictation.exam and not know it until they try to start dictation.
• Paper requisition becomes an important piece of information.Paper requisition becomes an important piece of information.

Web-Based SystemsWeb-Based Systems
 Web-based systems are similar to a client/serverWeb-based systems are similar to a client/server
systems.systems.
 Biggest differences are that images and applicationBiggest differences are that images and application
software are held centrally and loads to the clientsoftware are held centrally and loads to the client
display.display.
 Only the images are held at the archive.Only the images are held at the archive.

 Hardware at the client can be anything that will support anHardware at the client can be anything that will support an
appropriate web browser.appropriate web browser.
• This condition allows for greater flexibility with hardware.This condition allows for greater flexibility with hardware.
• This can be a disadvantage because low-end PCs can be used andThis can be a disadvantage because low-end PCs can be used and
the image displays (monitors) may not be diagnostic quality.the image displays (monitors) may not be diagnostic quality.
 The same application can be used on-site and at home inThe same application can be used on-site and at home in
teleradiology situations.teleradiology situations.
• Teleradiology is the reading of images from outside of the hospitalTeleradiology is the reading of images from outside of the hospital
walls.walls.

 System functionality may be limited because of software notSystem functionality may be limited because of software not
being locally installed.being locally installed.
• Bandwidth of the network connection limits the amount of dataBandwidth of the network connection limits the amount of data
that can be transmitted.that can be transmitted.
• Some programs are large and cannot be transmitted via aSome programs are large and cannot be transmitted via a
network.network.
 Network is the biggest obstacle to performance.Network is the biggest obstacle to performance.

 Most interactive part of PACSMost interactive part of PACS
 Hands-on componentHands-on component
 Consists of the following:Consists of the following:
• MonitorMonitor
• Computer with a mouse and keyboardComputer with a mouse and keyboard
 Different hardware requirements for each systemDifferent hardware requirements for each system

 Conventional film/screenConventional film/screen
radiography uses large multiviewerradiography uses large multiviewer
lightboxes.lightboxes.
 With early PACS, radiologistsWith early PACS, radiologists
thought that they needed four to sixthought that they needed four to six
monitors.monitors.
 Now, as radiologists have becomeNow, as radiologists have become
more comfortable, the number ofmore comfortable, the number of
monitors has dropped to anmonitors has dropped to an
average of two.average of two.
 Drop can be attributed to continuedDrop can be attributed to continued
development of viewing softwaredevelopment of viewing software
and better hardware.and better hardware.

 MonitorMonitor
• One of the most important elementsOne of the most important elements
• Several types of monitorsSeveral types of monitors
• Cathode ray tube (CRT)Cathode ray tube (CRT)
• Liquid crystal display (LCD)Liquid crystal display (LCD)

 Monitor, continuedMonitor, continued
 CRTCRT
• HeavyHeavy
• Puts off a lot of heatPuts off a lot of heat
• Very bright (good thing)Very bright (good thing)
• Can view from most any angleCan view from most any angle

 Monitor, continuedMonitor, continued
 LCDLCD
• Dropped in price and has risen in quality.Dropped in price and has risen in quality.
• LCD will soon take over PACS display market because of itsLCD will soon take over PACS display market because of its
size, resolution, and lack of heat production.size, resolution, and lack of heat production.
• LCD requires less maintenance.LCD requires less maintenance.
• LCD gives more light.LCD gives more light.
• LCD can be used in areas with a high amount of ambient light.LCD can be used in areas with a high amount of ambient light.

 Resolution and orientation of theResolution and orientation of the
monitor is a factor in determiningmonitor is a factor in determining
which type of monitor is to be used.which type of monitor is to be used.
 Most cross-sectional imaging is readMost cross-sectional imaging is read
on a 1K square monitor.on a 1K square monitor.
 Most computed radiography (CR) andMost computed radiography (CR) and
digital radiography (DR) images aredigital radiography (DR) images are
read on at least a 2K portrait monitor.read on at least a 2K portrait monitor.

 Number of pixels contained on a display is known asNumber of pixels contained on a display is known as
its resolution.its resolution.
 More pixels: The higher the resolution, the more informationMore pixels: The higher the resolution, the more information
that can be displayed.that can be displayed.
 Resolution also is defined as the process or capability ofResolution also is defined as the process or capability of
distinguishing between individual parts of an image that aredistinguishing between individual parts of an image that are
adjacent.adjacent.

 Pixels are arranged in a matrix.Pixels are arranged in a matrix.
 Common screen resolutions found on today’sCommon screen resolutions found on today’s
monitors are the following:monitors are the following:
• 12801280 ×× 1024 (1K)1024 (1K)
• 16001600 ×× 1200 (2K)1200 (2K)
• 20482048 ×× 1536 (3K)1536 (3K)
• 20482048 ×× 2560 (5K)2560 (5K)

 Medical displays are generally higher quality thanMedical displays are generally higher quality than
displays for other applications.displays for other applications.
 Radiologists use highest-resolution monitorsRadiologists use highest-resolution monitors
available for the modality that is being read:available for the modality that is being read:
 Mammography requires a 5K or 5-megapixel resolution.Mammography requires a 5K or 5-megapixel resolution.
 Cross-sectional image only requires a 1K monitor.Cross-sectional image only requires a 1K monitor.
 If referring physician is not the primary doctor reading theIf referring physician is not the primary doctor reading the
exams, a 1K monitor would be sufficient.exams, a 1K monitor would be sufficient.

 Workstations can be categorized by use:Workstations can be categorized by use:
 Primary reading stations for radiologistsPrimary reading stations for radiologists
 Review stations for referring physiciansReview stations for referring physicians
 Technologist quality control (QC) station for technologistTechnologist quality control (QC) station for technologist
review of imagesreview of images
 Image management station for the file room personnelImage management station for the file room personnel
 Each has a specific, main purpose.Each has a specific, main purpose.
 Workstations are placed in strategic areas near theWorkstations are placed in strategic areas near the
end-user of that particular need.end-user of that particular need.
 Workstations may be made up of different hardwareWorkstations may be made up of different hardware
depending on demand and need of user anddepending on demand and need of user and
requirements of the software that will be used.requirements of the software that will be used.

Radiologist Reading StationsRadiologist Reading Stations
 Station is used by a radiologistStation is used by a radiologist
to make a primary diagnosis.to make a primary diagnosis.
 Station will have the highest-Station will have the highest-
quality hardware, includingquality hardware, including
best monitor.best monitor.
 Computer hardware usedComputer hardware used
depends on the needs of thedepends on the needs of the
PACS vendor but usually isPACS vendor but usually is
robust, with little downtime.robust, with little downtime.

 Keyboard and mouse can be customized to needs ofKeyboard and mouse can be customized to needs of
department.department.
 Many different styles of mice are available.Many different styles of mice are available.
 Access to the RIS is nearby.Access to the RIS is nearby.

 Dictation system is near or is connected to PACSDictation system is near or is connected to PACS
station.station.
 Many systems are integrating the RIS and dictationMany systems are integrating the RIS and dictation
system within the PACS software.system within the PACS software.
 Grouping allows a more seamless workflow with littleGrouping allows a more seamless workflow with little
to no paper.to no paper.
 Station streamlines the completion of the study.Station streamlines the completion of the study.

Physician Review StationsPhysician Review Stations
 Station is a step-down model ofStation is a step-down model of
the radiologist’s reading station.the radiologist’s reading station.
 Station may have the same levelStation may have the same level
of software but may reduce someof software but may reduce some
advanced functions.advanced functions.
 One of the most importantOne of the most important
features is ability to view currentfeatures is ability to view current
and previous reports with images.and previous reports with images.
 Many vendors are integrating theMany vendors are integrating the
RIS functions with PACSRIS functions with PACS
software.software.

 Most referring physicians want to read radiologist’sMost referring physicians want to read radiologist’s
report along with viewing images.report along with viewing images.
 Many times, report is more important to them thanMany times, report is more important to them than
the images.the images.
 Software may be loaded on a stand-alone station thatSoftware may be loaded on a stand-alone station that
is dedicated to viewing images.is dedicated to viewing images.
 Or, software may be delivered over a web browser onOr, software may be delivered over a web browser on
any personal computer within an office or floor.any personal computer within an office or floor.

 In high-volume areas such as theIn high-volume areas such as the
emergency room and intensive care unit,emergency room and intensive care unit,
there are dedicated PACS workstationsthere are dedicated PACS workstations
strictly for image viewing.strictly for image viewing.
 These may have the higher-end monitors,These may have the higher-end monitors,
but many may have a lower-end monitorbut many may have a lower-end monitor
because of the costs.because of the costs.
 One of the greatest advantages of aOne of the greatest advantages of a
PACS is the ability to view the same setPACS is the ability to view the same set
of images in multiple locations at oneof images in multiple locations at one
time.time.
 Referring physician can pull up theReferring physician can pull up the
patient’s images in the office and read thepatient’s images in the office and read the
radiologist’s report and then call theradiologist’s report and then call the
radiologist on the phone and consult whileradiologist on the phone and consult while
both parties are viewing the same set ofboth parties are viewing the same set of
images.images.
 Continuity and speed of patient care hasContinuity and speed of patient care has
shown improvement with the use ofshown improvement with the use of
PACS.PACS.

Technologist QC StationsTechnologist QC Stations
 Used to review images afterUsed to review images after
acquisition but before sendingacquisition but before sending
them to the radiologistthem to the radiologist
 May be used to improve or adjustMay be used to improve or adjust
image-quality characteristicsimage-quality characteristics
 May be used to verify patientMay be used to verify patient
demographic informationdemographic information
 Placed between the CR and DRPlaced between the CR and DR
acquisition modalities as a pass-acquisition modalities as a pass-
through to ensure that the imagesthrough to ensure that the images
have met the departmental qualityhave met the departmental quality
standardstandard

Technologist QC StationTechnologist QC Station
 Generally has a 1K monitor.Generally has a 1K monitor.
 Does not have the resolution capabilities of the radiologist’sDoes not have the resolution capabilities of the radiologist’s
reading station.reading station.
 Care required of technologist when manipulating images not toCare required of technologist when manipulating images not to
change the appearance too much from original acquired image.change the appearance too much from original acquired image.
 Technologist should consult frequently with the radiologist toTechnologist should consult frequently with the radiologist to
ensure quality.ensure quality.
 Station can also be used to query and retrieve historic images toStation can also be used to query and retrieve historic images to
check previous pathologic conditions or body characteristics.check previous pathologic conditions or body characteristics.
 Station can help with the selection of technical factors orStation can help with the selection of technical factors or
procedural protocol.procedural protocol.
 QCQC station can afford same benefit as pulling the film jacket.station can afford same benefit as pulling the film jacket.

The File Room WorkstationThe File Room Workstation
 Before PACS, file room was a large openBefore PACS, file room was a large open
room with endless rows of shelves full ofroom with endless rows of shelves full of
film jackets.film jackets.
 Today, it may be as simple as severalToday, it may be as simple as several
computers and a dry laser to make copiescomputers and a dry laser to make copies
for outside needs.for outside needs.
 Workstation may be used to look upWorkstation may be used to look up
exams for a physician or to print copies ofexams for a physician or to print copies of
images for the patient to take to animages for the patient to take to an
outside physician.outside physician.
 Many hospitals are moving away fromMany hospitals are moving away from
printing films because of the cost.printing films because of the cost.
 Hospitals are moving toward burningHospitals are moving toward burning
compact disks (CDs) with the patient’scompact disks (CDs) with the patient’s
images.images.
 CDs can be made quickly and at aCDs can be made quickly and at a
reduced cost compared with film.reduced cost compared with film.

Common FunctionsCommon Functions
 Navigation functionsNavigation functions
 Image manipulation and enhancement functionsImage manipulation and enhancement functions
 Image management functionsImage management functions
 Advanced workstation functionsAdvanced workstation functions

Navigation FunctionsNavigation Functions
 Used to move through images, series, studies, andUsed to move through images, series, studies, and
patientspatients
 Worklist used to navigate through patient filesWorklist used to navigate through patient files
 Customizable for the userCustomizable for the user

 Modern PACS software conforms to the windowsModern PACS software conforms to the windows
look and feel:look and feel:
 Use of grab bars on the right hand side of windows to scrollUse of grab bars on the right hand side of windows to scroll
through a listthrough a list
 Activation of the scroll wheel on the mouse to scroll throughActivation of the scroll wheel on the mouse to scroll through
the listthe list

 Mouse is a useful navigation tool.Mouse is a useful navigation tool.
 Right mouse button offers many shortcut features inRight mouse button offers many shortcut features in
a menu of frequently used tasks and applications.a menu of frequently used tasks and applications.
 Hanging protocols are available:Hanging protocols are available:
 Each user has the ability to set up a custom hangingEach user has the ability to set up a custom hanging
protocol.protocol.
 Protocol is defined as how a set of images will be displayedProtocol is defined as how a set of images will be displayed
on the monitor.on the monitor.

 Hanging protocolsHanging protocols
 Example:Example:
• CT exam is selected.CT exam is selected.
• Can be viewed four images on each monitor.Can be viewed four images on each monitor.
• CR image is selected.CR image is selected.
• Can be viewed as one image on each monitor.Can be viewed as one image on each monitor.
 Protocol can also be specified to show the previous exam onProtocol can also be specified to show the previous exam on
one monitor and the current exam on the other.one monitor and the current exam on the other.
 Once set, the most efficient study navigation is determined.Once set, the most efficient study navigation is determined.

Study NavigationStudy Navigation
 A study in PACS is the current or previous examA study in PACS is the current or previous exam
being viewed.being viewed.
 Study may consist of two or three single images such as theStudy may consist of two or three single images such as the
case with CR and DR.case with CR and DR.
 Study may contain several series of images such as theStudy may contain several series of images such as the
case with MRI.case with MRI.
 Images can be simply paged through with the scroll wheel orImages can be simply paged through with the scroll wheel or
arrows on the keyboard.arrows on the keyboard.

 Images can be run through in stacks.Images can be run through in stacks.
 Stack mode of scrolling through images made is calledStack mode of scrolling through images made is called
“cine.”“cine.”
• Cine means to move through frame by frame of the series ofCine means to move through frame by frame of the series of
images.images.
 Study may have an automatic setting that will run throughStudy may have an automatic setting that will run through
the images at a preset pace.the images at a preset pace.
 Cine function is used most often in cross-sectional imaging.Cine function is used most often in cross-sectional imaging.

 Icon may be available for the following:Icon may be available for the following:
 To move between a patient’s various studiesTo move between a patient’s various studies
 To open the next unread patient file in the worklistTo open the next unread patient file in the worklist
 To close patient or study iconTo close patient or study icon
• Closes the active patient or studyCloses the active patient or study
• Pulls up the worklist or moves to the next unread patientPulls up the worklist or moves to the next unread patient
 Customizable rules can be set up per user toCustomizable rules can be set up per user to
optimize workflow.optimize workflow.

Image Manipulation and EnhancementImage Manipulation and Enhancement
FunctionsFunctions
 ToolsTools
 Window/levelWindow/level
• May be a default function of the left mouse button.May be a default function of the left mouse button.
 By depressing and holding down the mouse button and movingBy depressing and holding down the mouse button and moving
the mouse up and down and left and right, the window and levelthe mouse up and down and left and right, the window and level
can be adjusted.can be adjusted.
• Window represents the range of gray values.Window represents the range of gray values.
• Level represents the center value of the range.Level represents the center value of the range.
• A change in the window and level appears to change theA change in the window and level appears to change the
brightness and contrast of the image.brightness and contrast of the image.

FunctionsFunctions
 Tools, continuedTools, continued
 AnnotationsAnnotations
• Annotations are NOT to be used to label left or right to indicateAnnotations are NOT to be used to label left or right to indicate
the patient’s side.the patient’s side.
• Annotations are used to indicate prone or supine, 30 minutes,Annotations are used to indicate prone or supine, 30 minutes,
upright or flat.upright or flat.
• Any other image information is appropriate.Any other image information is appropriate.
• Radiologist will place arrows or circles around pathologic orRadiologist will place arrows or circles around pathologic or
questionable areas.questionable areas.

FunctionsFunctions
 Flip and rotateFlip and rotate
• Tool is used to orient the image in the correct anatomic hangingTool is used to orient the image in the correct anatomic hanging
position.position.
• Tool is usually a left-to-right flip and a 90-degree clockwise andTool is usually a left-to-right flip and a 90-degree clockwise and
counterclockwise icon.counterclockwise icon.
• Use of lead markers is important to ensure that the radiologistUse of lead markers is important to ensure that the radiologist
is reading the correct side.is reading the correct side.
• Digital R and L may not be upheld in court during a legal caseDigital R and L may not be upheld in court during a legal case
because of the ability to mark anywhere on the image and flipbecause of the ability to mark anywhere on the image and flip
and rotate the image into any layout on the screen.and rotate the image into any layout on the screen.

FunctionsFunctions
 Pan, zoom, and magnifyPan, zoom, and magnify
• Tools are used primarily by the radiologistTools are used primarily by the radiologist
to increase the size of an area on theto increase the size of an area on the
image.image.
• Magnify usually magnifies a square area ofMagnify usually magnifies a square area of
the image.the image.
 Square can be moved around the image toSquare can be moved around the image to
quickly see various areas magnified.quickly see various areas magnified.
• Pan and zoom functions are usually usedPan and zoom functions are usually used
together.together.
 Image is first zoomed up to the desiredImage is first zoomed up to the desired
magnification level.magnification level.
 Pan icon is activated.Pan icon is activated.
 Zoomed image can be moved around toZoomed image can be moved around to
view the different areas of the image.view the different areas of the image.

FunctionsFunctions
 MeasurementsMeasurements
• Various measurement functions areVarious measurement functions are
found on a PACS station.found on a PACS station.
• Most common is the distanceMost common is the distance
measurement.measurement.
• Size of a pixel is a knownSize of a pixel is a known
measurement, so the software hasmeasurement, so the software has
the ability to measure structures onthe ability to measure structures on
the image based on this.the image based on this.
 Another common measurement is anAnother common measurement is an
angle measurement.angle measurement.
• Can give an angle measurementCan give an angle measurement
between two structuresbetween two structures
• Commonly used when reading spineCommonly used when reading spine
studiesstudies

FunctionsFunctions
 MeasurementsMeasurements
• Region of interestRegion of interest
• Measurement tool determines the pixel intensity of a certain area.Measurement tool determines the pixel intensity of a certain area.
• Each type of tissue or fluid has a different intensity of reading.Each type of tissue or fluid has a different intensity of reading.
• Radiologist can make a determination whether something is solidRadiologist can make a determination whether something is solid
or fluid.or fluid.

Image Management FunctionsImage Management Functions
 Patient demographicsPatient demographics
 Patient demographics must be correct.Patient demographics must be correct.
• If demographics are not correct at the archive level, the imagesIf demographics are not correct at the archive level, the images
could be lost.could be lost.
 Changes should only be made when the information isChanges should only be made when the information is
absolutely known to be wrong.absolutely known to be wrong.
 Many hospitals allow only certain persons the access toMany hospitals allow only certain persons the access to
change demographics just to keep the errors to a minimum.change demographics just to keep the errors to a minimum.

 Query/retrieve iconQuery/retrieve icon
• Used to retrieve on demand anyUsed to retrieve on demand any
studies from the archivestudies from the archive
• Allows user to query a study onAllows user to query a study on
multiple fieldsmultiple fields
• Patient’s name or identificationPatient’s name or identification
• Date of serviceDate of service
• ModalityModality
• Diagnosis code or comment fieldDiagnosis code or comment field

 CD burning optionCD burning option
 Feature may only be available in the file room to control the CDsFeature may only be available in the file room to control the CDs
that are sent out.that are sent out.
 HIPAA (Health Insurance Portability and Accountability Act)HIPAA (Health Insurance Portability and Accountability Act)
compliance must also be maintained.compliance must also be maintained.
 Copy and pasteCopy and paste
 Function is used with the web-based systems when creatingFunction is used with the web-based systems when creating
presentations for conferences.presentations for conferences.
 Patient information must be removed from the image before it isPatient information must be removed from the image before it is
placed into a presentation.placed into a presentation.

 Print filmsPrint films
 Printing is usually only done in the file room so that control canPrinting is usually only done in the file room so that control can
be maintained over the printed films for HIPAA purposes andbe maintained over the printed films for HIPAA purposes and
cost reasons.cost reasons.
 Workstations may be connected to paper printers for quickWorkstations may be connected to paper printers for quick
consults and for medical records.consults and for medical records.

Advanced Workstation FunctionsAdvanced Workstation Functions
 Advanced functions are usually placed on specialtyAdvanced functions are usually placed on specialty
workstations for the radiologist, and some are foundworkstations for the radiologist, and some are found
on the technologist QC station to further enhance theon the technologist QC station to further enhance the
images. The following is a bulleted list of some of theimages. The following is a bulleted list of some of the
most common advanced functions:most common advanced functions:
 Multiplanar reconstruction (MPR)Multiplanar reconstruction (MPR)
 Maximum intensity projection and minimum intensityMaximum intensity projection and minimum intensity
projection (MIP and MinIP)projection (MIP and MinIP)
 Volume rendering techniqueVolume rendering technique
 Shaded surface displayShaded surface display
 StitchingStitching

Reading Station Advanced FunctionsReading Station Advanced Functions
 Multiplanar reconstruction (MPR)Multiplanar reconstruction (MPR)
• MPR is one of the most commonlyMPR is one of the most commonly
used three-dimensional renderingused three-dimensional rendering
techniques.techniques.
• When doing a CT scan of aWhen doing a CT scan of a
patient, thin axial slices can bepatient, thin axial slices can be
acquired of a volume of tissue.acquired of a volume of tissue.
• Slices can then be loaded into theSlices can then be loaded into the
MPR software, and aMPR software, and a
reconstruction in another planereconstruction in another plane
can be produced.can be produced.
• Most common application isMost common application is
producing coronal images fromproducing coronal images from
the axial set to reduce radiation tothe axial set to reduce radiation to
the patient and scan time at thethe patient and scan time at the
modality.modality.

 Maximum intensityMaximum intensity
projection and minimumprojection and minimum
intensity projection (MIPintensity projection (MIP
and MinIP)and MinIP)
• Function is used toFunction is used to
visualize vessels (MIP) andvisualize vessels (MIP) and
air-filled structures (MinIP).air-filled structures (MinIP).
• Function is commonlyFunction is commonly
performed after injection ofperformed after injection of
contrast medium on CTcontrast medium on CT
and MRI studies.and MRI studies.
• Contrast medium showsContrast medium shows
areas of strictures andareas of strictures and
blockages within theblockages within the
vessels.vessels.

 Volume renderingVolume rendering
techniquetechnique
• Function is similar toFunction is similar to
MIP.MIP.
• Function allows user toFunction allows user to
assign colors based onassign colors based on
the intensity of thethe intensity of the
tissue.tissue.
• Bone, contrastBone, contrast
medium, and organsmedium, and organs
can be visualized usingcan be visualized using
various colors.various colors.
• Function uses aFunction uses a
histogram-type graph tohistogram-type graph to
differentiate the variousdifferentiate the various
structures.structures.

 Shaded surfaceShaded surface
displaydisplay
• Using a threshold ofUsing a threshold of
pixel intensity values,pixel intensity values,
everything below theeverything below the
threshold is removedthreshold is removed
and everything aboveand everything above
is assigned a coloris assigned a color
and is shown as aand is shown as a
three-dimensionalthree-dimensional
object.object.

Technologist QC StationTechnologist QC Station
Advanced FunctionsAdvanced Functions
 StitchingStitching
• Stitching is used when multiple images need toStitching is used when multiple images need to
be put together in one image.be put together in one image.
 Most common application is for full-spineMost common application is for full-spine
radiographs or a scoliosis series.radiographs or a scoliosis series.
– Exam was traditionally performed on a 3-foot filmExam was traditionally performed on a 3-foot film
and was processed.and was processed.
 CR manufacturers have developed a 3-foot CRCR manufacturers have developed a 3-foot CR
cassette that contains multiplecassette that contains multiple image platesimage plates
(IPs).(IPs).
– Each of the IPs is scanned through the reader,Each of the IPs is scanned through the reader,
and the individual images are sent to the QCand the individual images are sent to the QC
workstation.workstation.
– Software interpolates images and connects themSoftware interpolates images and connects them
using known markers from the IPs.using known markers from the IPs.
– Technologist has the ability to adjust theTechnologist has the ability to adjust the
connection of the images.connection of the images.
 Long leg images are used for leg-lengthLong leg images are used for leg-length
discrepancy.discrepancy.
 If the special 3-foot cassettes are not available,If the special 3-foot cassettes are not available,
a radiopaque ruler can be used to ensure thata radiopaque ruler can be used to ensure that
the images are stitched at the right area.the images are stitched at the right area.

Image PostprocessingImage Postprocessing
 Many other advanced workstation functionsMany other advanced workstation functions
are available to be added to the PACSare available to be added to the PACS
workstation. This is a growing field withworkstation. This is a growing field with
advancements coming each year. Specificadvancements coming each year. Specific
information about how to perform theseinformation about how to perform these
procedures can be found in the vendor’s userprocedures can be found in the vendor’s user
manual.manual.

SummarySummary
 A PACS consists of digital acquisition, displayA PACS consists of digital acquisition, display
workstations, and storage devices interconnectedworkstations, and storage devices interconnected
through an intricate network.through an intricate network.
 Digital imaging and communications in medicineDigital imaging and communications in medicine
(DICOM)(DICOM) is a universally accepted standard foris a universally accepted standard for
exchanging medical images between the modality,exchanging medical images between the modality,
viewing stations, and the archive.viewing stations, and the archive.
 A display workstation is any computer that a healthA display workstation is any computer that a health
care worker uses to view a digital image, and it is thecare worker uses to view a digital image, and it is the
most interactive part of a PACS.most interactive part of a PACS.
 The archive is the central part of the PACS andThe archive is the central part of the PACS and
houses all of the historic data along with the currenthouses all of the historic data along with the current
data being generated.data being generated.
 Workflow is how a process is done step by step orWorkflow is how a process is done step by step or
how a task is completed.how a task is completed.

SummarySummary
 System architecture is the basic organizationSystem architecture is the basic organization
of a system, come to life in its components,of a system, come to life in its components,
their associations to each other and thetheir associations to each other and the
environment, and the principles leading itsenvironment, and the principles leading its
design and development, or in other words,design and development, or in other words,
system architecture can be defined as thesystem architecture can be defined as the
hardware and software infrastructure of thehardware and software infrastructure of the
systems workflow.systems workflow.
 Common system architectures found with aCommon system architectures found with a
PACS are client/server-based systems,PACS are client/server-based systems,
distributed or stand-alone systems, and web-distributed or stand-alone systems, and web-
based systems.based systems.

SummarySummary
 Display stations can be categorized by their means ofDisplay stations can be categorized by their means of
use, such as primary reading stations for radiologists,use, such as primary reading stations for radiologists,
review stations for referring physicians, technologistreview stations for referring physicians, technologist
QC stations for technologist review of images, andQC stations for technologist review of images, and
image management stations for the file roomimage management stations for the file room
personnel.personnel.
 Many functions are available on a PACS workstation,Many functions are available on a PACS workstation,
and each set of functions can be broken down intoand each set of functions can be broken down into
four categories: navigation functions, imagefour categories: navigation functions, image
manipulation and enhancement functions, imagemanipulation and enhancement functions, image
management functions, and advanced workstationmanagement functions, and advanced workstation
functions.functions.

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