PACS FINAL 1ST WEEK B

Physician Review Stations

The physician review workstation is a step-down model of the radiologist reading station. One of its most important features is the ability to view current and previous reports along with the images.

Physician Review Stations - High-Volume Areas

In high-volume areas such as the emergency room and the intensive care unit, there are dedicated PACS workstations for image viewing.

Physician Review Stations - PACS Advantage

One of the greatest advantages of a PACS is the ability to view the same set of images in multiple locations at the same time, allowing physicians and radiologists to consult simultaneously, improving continuity and speed of patient care.

Technologist Quality Control (QC) Stations - Definition

The technologist QC station is used to review images after acquisition but before sending them to the radiologist. It may be used to improve or adjust image quality characteristics or to verify patient demographic information.

Technologist Quality Control (QC) Stations - Monitor Type

The technologist QC station generally has a 1K monitor. When manipulating images, the technologist must be careful not to change the appearance too much from the original acquired image.

Technologist QC Stations - Query and Retrieve

The QC workstation can also be used to query and retrieve historic images before beginning an examination so that the technologist can check previous pathology or body characteristics.

File Room/Image Management Stations - Function

The file room workstation may be used to look up examinations for a physician or to print copies of images for the patient to take to an outside physician.

File Room/Image Management Stations - Demographics

File room personnel may also be responsible for correcting patient demographics. If images with incorrect demographics are sent to the archive, it becomes difficult to pull those images the next time the patient comes in. The archive is a database and is only as good as the information put into it.

Common PACS Workstation Functions

Common functions found on PACS workstations include navigation functions, image manipulation and enhancement functions, image management functions, and advanced workstation functions.

Navigation Functions - Definition

Navigation functions are used to move through images, series, studies, and patients. The worklist is used to navigate through patients, and most modern PACS software conforms to a Windows-style interface.

Navigation Functions - Mouse and Scroll Features

Scroll bars, mouse scroll wheels, and right-click shortcut menus are common navigation tools that allow quick access to frequently used tasks and applications.

Hanging Protocols - Definition

A hanging protocol is how a set of images will be displayed on the monitor. Protocols may require showing previous exams on one monitor and current exams on another to improve study navigation efficiency.

Study Navigation - Definition

A study in PACS is the current or previous examination being viewed and may include a few images (projection radiography) or several series (MRI).

Study Navigation - Scrolling and Cine

Images can be paged using the scroll wheel, keyboard arrows, or run in stacks using the cine function, which is commonly used in sectional imaging.

Study Navigation - Close Patient/Close Study

A close patient or close study icon closes the active patient or study and either returns to the worklist or opens the next unread patient.

Image Manipulation - Window Width/Window Level

Window width and window level are adjusted using the mouse. Window width controls the range of gray values, and window level controls brightness.

Image Manipulation - Annotations

PACS allows annotation of text or graphics on the image, but digital R and L markers should not be used for legal labeling. Annotations may indicate positions or highlight pathology with arrows or circles.

Image Manipulation and Enhancement Functions - Flip and rotate

These functions are used to orient the image in the anatomic hanging position desired by the department. There are usually left-to-right flip and 90-degree clockwise and counterclockwise icons. This function makes it very important that lead markers are used to ensure that the radiologist reads the correct side.

Image Manipulation and Enhancement Functions - Pan, zoom, and magnify

These functions are used primarily by the radiologist to increase the size of an area on the image. The magnify function will usually enlarge a square area of the image, and the square can be moved around the image to quickly see various areas enlarged. The pan and zoom functions are usually used together. The image is first zoomed up to the desired magnified level, and then the pan icon is activated so that the zoomed image can be moved around, allowing the user to view the different areas of the image.

Image Manipulation and Enhancement Functions - Measurements

Various measurement functions are found on a PACS station. The most common is the distance measurement. The size of a pixel is a known measurement, so the software can measure structures on the image based on this known measurement. Another common measurement is the angle measurement, which measures the angle between two structures; this measurement function is commonly used when reading spine studies.

Image Manipulation and Enhancement Functions - Measurements (ROI)

Another common measurement a radiologist may use is a region of interest (ROI), which will determine the pixel intensity of a certain area. Because each type of tissue or fluid has a little bit different intensity reading, the radiologist can make a determination whether something is solid or fluid.

Image Management Functions

Most PACS allow the user to modify patient demographics at the technologist QC station, the reading station, and the file room station. It is imperative that the patient demographics are correct. If wrong information is archived on an image, the image will be difficult to retrieve and may never be found again.

Image Management Functions - Query/Retrieve

Another image management function is the query/retrieve function used to retrieve studies from the archive. The query function allows the user to query a study on multiple fields such as the patient's name or ID, date of service, or modality. Some systems also allow a query based on a diagnosis code or comment field.

Image Management Functions - CD burning

Many vendors have provided a CD-burning option that allows users to save studies to a CD for outside use. The feature may be available only in the file room to control the CDs that are sent out. Health Insurance Portability and Accountability Act (HIPAA) compliance must also be maintained.

Image Management Functions - Copy and paste images

Another common feature is the ability to copy and paste images into a document. This is frequently used with the web-based systems when creating presentations for conferences. The patient information must be removed from the image before it is placed into a presentation.

Advanced Workstation Functions - Multiplanar Reconstruction (MPR)

One of the most commonly used three-dimensional (3D) rendering techniques. When doing a CT scan of a patient, thin axial slices can be acquired of a volume of tissue. The slices can then be loaded into the MPR software, and a reconstruction in another plane can be produced. The most common application is producing coronal images from the axial set to reduce radiation to the patient and to reduce scan time at the modality.

Maximum Intensity Projection and Minimum Intensity Projection (MIP and MinIP)

Used to visualize vessels (MIP) and air-filled structures (MinIP). Commonly performed after the injection of contrast on CT and MRI studies, the contrast will show areas of strictures and blockages within the vessels.

Advanced Workstation Functions - Volume Rendering Technique (VRT)

Similar to MIP but allows the user to assign colors based on the intensity of the tissue so that bone, contrast agent, and organs can be seen in different colors. The technique uses a histogram-type graph to differentiate the various structures.

Advanced Workstation Functions - Shaded Surface Display (SSD)

Using a threshold of pixel intensity values, everything below the threshold will be removed, and everything above will be assigned a color and shown as a 3D object.

Technologist Quality Control Station - Stitching

Used when multiple images need to be put together into one image. The most common application is for full-spine X-rays or a scoliosis series. The examination was traditionally performed on a 3-foot film and processed.

Technologist Quality Control Station - Stitching (3-foot cassette method)

Manufacturers have developed a 3-foot cassette that contains multiple imaging plates (IPs). Each of the IPs is scanned through the reader, and the individual images are sent to the QC workstation. The software then interpolates the images and connects them using known markers from the IPs.

Technologist Quality Control Station - Stitching (Leg length studies)

Another application of stitching is producing long leg images for leg length discrepancy studies. The images are acquired in a fashion similar to the one described above and stitched together. If the special 3-foot cassettes are not available, a radiopaque ruler must be used to ensure that the images are stitched at the right area.

Technologist Quality Control Station - Image Post-Processing

Regarded as an advanced function of the workstation, such as edge enhancement, smoothing, and contrast enhancements.