Week 7 - Post Processing Flashcards
What are the 2 principal parts of a computer?
Hardware
Software
-motherboard
-hard drive
-memory
-peripherals
Hardware (physical components)
-system
-application
Software (system components)
The large circuitry board that contains the components that make the computer function
Consists of:
-central processing unit (CPU)
-basic input/output system (BIOS)
-Bus
-ports
-memory
Motherboard
The brain of the computer; processes all data and computes all commands
Central processing unit (CPU)
Runs start up diagnostics during boot up to ensure all peripherals are functioning; manages flow between the OS and the hardware
Basic input/output system (BIOS)
A series of connections, controllers and chips that create the information highway of the computer
Bus
Used to store information currently being processed within CPU
Memory
-main repository for programs and documents
-made up of hard, thin magnetic platters that are stacked one on top of the other
Hard drive
CD/DVD, redundant array of inexpensive discs (RAID) and flash drives
Secondary memory storage
A collection of connectors
Ports
T/F
More pixels = greater resolution
True
Monitor similar to the xray tube
Cathode ray tube (CRT)
Produces images by shining or reflecting light through a layer of liquid crystal and a series of colour filters
Liquid crystal display (LCD)
Made up of many small fluorescent lights that are illuminated to form the colour of the image
Plasma display
Programs that allow the hardware to run properly (background task management)
System software
Programs that allow users to do specific tasks (word processing)
Application software
-two or more devices sharing resources and information
-computer, terminals, and servers that are interconnected by communication channels sharing data and program resources
Computer network
-small network
-less expensive to install
-faster due to their smaller size
-PACS workstations in a radiology reading room are considered this type
Local area network
LAN NETWORK
-spans a large area
-connects computers that are not physically attached through cables but attached by other means (telephone lines, satellite links)
-higher operating costs due to high speed equipment used to run these networks
Wide are network
WAN network
-centralized computer controls operations, files, and sometimes the programs attached to the network
-server provides a location for centralized storage and retrieval on the network
-allows users to access files while moving from computer to computer
Ex. PACS read and distributes images across the hospital
Server based network
-like server based network
-server processes the resources as requested by the client and returns only the results back to the client
Ex. Mail server - send a copy of an email to multiple devices that fetch the information
Client based network
What are some examples of systems involved in medical imaging?
-DICOM
-HL-7
-HIS
-RIS
-PACS
DICOM
Digital imaging communication system
HL-7
Health level 7
The core informational system for patient management across the health care system
Hospital information system
HIS
The core system for the electronic management of imaging departments
Contains all radiology specific data
Radiology information system
RIS
PACS
Picture archiving and communication system
What are the fundamentals of PACS?
Image acquisition
Display workstation
Archive servers
T/F
In image acquisition, most images are acquired in a digital form
True
Reading images on the computer without hard copy films
Soft copy reporting
The most interactive part of A PACS and can be found throughout the department as well as outside radiology
Display workstation
-receives the images form the archive or from various radiology modalities and presents them for viewing
What is the most important element of the PACS display station?
The monitor
Has PACS application software that allows the user to perform minor image manipulation techniques to optimize the image being viewed
Display workstation
-used to make diagnosis
-have highest quality hardware, including high resolution monitors
-customizable keyboard, mouse, dictation hardware
-integrated RIS with dictation system or connected to PACS
Radiologist reading station
-step down model of the radiologist reading station
-same level of software without some of the more advanced functions
-one of the most important features is the ability to view current and previous reports along with the images
Physician review station
-used to review images after acquisition but before sending them to the rad
-may be used to improve or adjust image quality characteristics
Technologist station
-may be used to look up exams for a physician or to print out copies of images for the patient to take to an outside physician or burn CD
-may also be responsible for correcting patient demos
Image management station
-the central parts of the PACS and houses all the historic data along with the current data being generated
Composed of:
-short and long term storage
-computer that controls the PACS workflow
-data base serves or image manager
Archive servers
What is the archival workflow for DR?
-order entry
-patient info/orders are verified by the technologist
-exam is performed
-images are critiqued and repeated if necessary
-images sent to appropriate workstation
-rad dictates/transcribed report
-means being online or available very quickly (usually 3-5seconds)
-is commonly a redundant array of independent disks
Short term storage
-images that must be retrieved, could take 1-5 minutes
-RAID is becoming most cost effective, and many hospitals are using them for both long and short term archive
Long term storage
Scans an analog film and produces numerical signals for each part of the scanned film
Used for:
-teleradiography
-film duplication
-computer aided diagnosis (CAD)
Film digitizers
Known as film printers, they print digital images on film
Two types:
-wet chemical: use chemicals to process film that has been exposed to the laser
-dry laser: use heat to produce the latent image that is etched into the film
Imagers
An alternative to printing films (more commonly used)
All PACS offer the ability to burn images
CD/DVD burners
Study that refers to the current or previous examination being viewed (ex. Left foot)
Study navigation
*buttons allow the user to look through patients previous studies, close the patient/study or to bring up the work list
Allows the user to modify patient demos at the technologist QC station, reading station, and file room station to ensure patient demos are correct
Image management functions
*this is imperative
Function allows the user to query a study on multiple fields
Query/retrieve
Option allow users to save studies to a CD for outside use
CD burning
How a set of images will be displayed on the monitor and are customizable
Hanging protocols
Increases/decreases image brightness
Sets the center or midpoint of the range of visible shades of grey
Window level
T/F
A lower window level will result in a brighter image
True
Because the window level is optimizing the brightness of lower pixels
Ex. Lungs
T/F
A higher window level will result in a darker image
True
Because the window level is optimizing the brightness of higher pixel intensities
Ex. Bones/mediastinum
The range of grey values that are being viewed (contrast)
Changing this allows for contrast to be increased/decreased
Window width
T/F
A narrow window width will have high contrast with few shades of grey
True
T/F
A wide window width will have many shades of grey with low contrast
True
Also called high pass filtering/sharpening
Allow high frequencies to be passed through to the final image and eliminates low frequencies
-increases contrast
Edge enhancement
Also called low pass filtering
Occurs by averaging each pixels frequency with surrounding pixel values to remove high frequency noise
-reduction of noise and contrast
-useful for viewing small structures such as fine bone and tissues
Smoothing
Allows addition of text or graphics onto the image
Annotations
Used to orient the image in correct anatomical hanging position
Flip/rotate
Will enlarge a square area on the image and can be moved around
Magnification
Image zoomed and panned around to see different areas of the image
Pan/zoom
Can measure distance, angles, ROI
Measurement
What are some examples of advanced workstation functions?
-reading station advanced functions (MRO, MIP, MinIP, VRT, SSD)
-technologist QC station advanced functions (stitching, image post processing)
One of the most common uses 3D rendering techniques
Slices are loaded into the MPR software and then reconstructed in another plane
Ex. Sagittal, coronal, paraxial
Multi planar reconstruction
MPR
A data visualization method that enables detection of high density structures in a given volume
Creates images by choosing only the highest tissue density
Maximum intensity projection
MIP
*commonly performed after the injection of contrast on a CT or MRI
A data visualization method that enables detection of low density structures
Creates an image by choosing only the lowest tissue density (density equal to or closest to air)
Minimum intensity projection
MinIP
*the airways and air filled lungs are highlighted for better analysis
-creates a 3D representation of data
-like MIP but allows the user to assign colour based on intensity of tissue so that bone, contrast agent and organ can be seen in different colours
Volume rendering technique
VRT
-creates a realistic 3D view of anatomic surfaces
-uses a pixel intensity threshold that will remove everything below the threshold, and everything above will be shown as a 3D object
Surface shaded display
SSD
Used when multiple images need to be put together into one image
Ex. Leg length, scoliosis
Stitching
What type of network is used for PACS?
Server based network
What type of network is popular for small offices or home network configurations?
Peer to peer
T/F
The HIS interfaces with the RIS (which communicates through an application layer of HL-7)
True
What is the PACS component that interfaces with the RIS and HIS?
-contains the master database of everything that is in the archive
-contains only the image header information, not the image data
Image manager
