RADIOLOGY MONITORS
The Monitor ~ the most important part of the workstation
With the falling prices of computer hardware, the most cost dependant component of the workstation is the monitor. In light of tight hospital budgets coexisting with an appreciation of proper patient diagnosis, the onus falls upon the workstation purchaser to determine which monitor is right for the job.
Generally, as the quality of the monitor increases, so does the amount of information that can be extracted from the image and, as importantly, so do the number of things that won?t be missed!
The short story?
Weighing all factors, the best all purpose monitor for the Radiologist who dictates all modalities is the grayscale 3 megapixel monitor.
Weighing all factors, the best all purpose monitor for the Clinician who reviews all modalities is the color 2 megapixel monitor.
The long story?
There are a few decisions to make regarding Radiology monitors.
- CRT or LCD
- Color or grayscale
- Portrait or landscape
- Single, dual, or quad
- High or low resolution
1. CRT (Cathode Ray Tube) vs. LCD (Liquid Crystal Display). The two major advantages of CRT?s over LCD?s are that they are less expensive and, due to their bulkiness, weight, and less attractive appearance, they are stolen less often. However, we recommend flat panel monitors for our workstations because they offer a more uniform image, put out less heat, require less electricity, last longer, are less variable, are easier to adjust, cost less to ship, cost less to repair, and take up less space.
2. Portrait vs. Landscape. Traditionally, computer monitors were ?landscape? mode which means the screen is wider than tall. We presume this is because manufacturers were attempting to emulate a familiar item ? the television screen. Until the age of cross sectional imaging, the CXR and KUB were two of the most popular studies obtained and therefore viewboxes were designed to be 14? wide x 17? tall to illuminate these studies. When cross sectional imaging initially came along, images were printed on film sized to be illuminated on traditional viewboxes and therefore 14? wide x 17? tall. This portrait mode has been carried over to current grayscale monitors since we are used to seeing studies this way.
Dual and Quad portrait mode monitors take up less horizontal space than the same number of landscape monitors. ROCOVIEW recommends portrait mode for all 4 monitor setups and generally portrait mode for 2 monitor setups that involve grayscale imaging for final interpretation. Due to the body habitus of many of the floor patients, frequently the CXR is taken horizontally so the clinician review stations there may be best oriented in landscape mode. All portrait mode monitors offered on the ROCOVIEW site allow for landscape mode also.
3. Color vs. Grayscale. Almost all of radiology can be displayed in 8 bit grayscale. The notable exceptions are ultrasound, nuclear medicine, some 3D reconstructive imaging, and occasionally plain film. It is my (GR) day-to-day experience that the color of ultrasound can easily be seen and interpreted on the grayscale images. Most nuclear medicine studies that invoke color (cardiology) are read on the dedicated nuclear medicine workstation. There is some advantage to color display with 3D images but this is debatable. There are arguments that plain film should be visualized in 10-bit ? in any event, it is imperative that the grayscale lookup table is accurate if 8-bit is used. However, if you want color for ultrasounds, nuclear medicine, 3D images, or internet browsing, we recommend a setup that includes a color display next to your grayscale monitors.
Beware: If you do not have a color monitor and its video card as part of the workstation system with the color monitor as the primary monitor, you may have problems properly displaying images with some popular monitor products. This issue is due to a problem with the way Windows handles the conversion of color to grayscale. The compatible video card with some monitor setups only display CT and MR images (8bit) in proper grayscale. On these systems, any image containing color is badly displayed and not diagnostic. Also, some vendors provide a system that displays color images nicely in grayscale (using a color video card in a PCI slot) without the color monitor, but the POST of the boot (containing critical boot information) does not display since the primary monitor is set to the color monitor which is non-existent. Also all error messages and information popup windows do not appear since they, too, are assigned to the primary monitor. This makes evaluation of a workstation that won?t boot impossible since you can?t see the error messages. There is no way to get the POST to appear on the secondary monitors since Windows only starts up AFTER the POST. Also remote access from a program such as PC Anywhere is a Windows program and requires completion of the boot to function. It should be stressed, however, that if the user DOES want to see some information in color, this problem is obviated for almost all monitor setups by adding a color monitor and video card.
4. Single vs. Dual vs. Quad monitors. This is highly dependant on the types of studies to be read on the monitors. There is overlap of monitor configurations owing to reading style. ROCOVIEW recommends:
Single:
? technologist stations
? file room stations
? clinicians in their office
? clinical review of imaging studies with or without comparison
? plain film review without comparison
? nuclear medicine
? ultrasound
? specials
? ER
? OR
? Teleradiology - wet reads from home covering ER without comparison
Dual
? clinical review of imaging studies with or without comparison
? ICU plain film review with comparison
? diagnostic interpretation of any modality
? diagnostic interpretation of plain film involving 2 images, or 1 current image with 1 comparison image
? Teleradiology - wet reads from home covering ER with or without comparison that may include plain film
? specials
? ER
Quad
? plain film evaluation - most helpful for CXR that includes PA and lateral with comparison, BE?s, UGI?s, IVP?s, bodygrams, specials
? MRI, CT with or without comparisons
5. High vs. Low resolution. There is a spectrum of monitor resolutions available. These used to be identified as ?1k? or ?2k? monitors. This designation indicated the number of pixels along the long axis of the 1k monitor was 1000 pixels (actually 1024) and the number of pixels along the short axis of the 2k monitor was 2000 pixels (actually 2048).
The modern designation of monitor resolution is in megapixels (MP) or millions of pixels. This is calculated as a product of the number of horizontal and vertical pixels. By this method, 1k monitors would be 1024 pixels x 768 pixels = 0.79MP and 2k monitors would be 2048 pixels x 2560 pixels = 5.2MP. With the development of LCD displays came many intermediate resolutions and the controversy regarding the minimum resolutions required to display images diagnostically. The old school statement ?1k for review and 2k for diagnosis? required reevaluation.
While the ACR recommends 2.5lp?s for large format images (plain film) this does not clearly address the issue related to total monitor size. Reading a high resolution study on a low resolution monitor means there is loss of potentially important detail. If something is missed and there is litigation, the smart attorney will have the study printed out in its native resolution to show clearly what was missed! Not only will the radiologist be shown to be negligent but the institution may also be brought in for providing inadequate equipment.
When it comes to CR and film digitization, it is senseless to obtain images at a resolution higher than the resolution used to interpret the images. This will set you up for the just described situation not to mention wasting the larger amount of time required to scan in an image at higher resolution and the waste of archive space storing the image at high resolution.
Since the cost of monitors increases dramatically with increased resolution, it is best to choose a monitor resolution that matches the minimum resolution required to read the highest resolution study. For example, if the monitor is used to interpret low resolution ultrasound and high resolution plain film, then a monitor of resolution sufficient to read plain film should be chosen. A recent article has suggested that there is no significant diagnostic difference in the interpretations of plain film between a 3MP and 5MP monitor, but this is not comprehensive and there is controversy.
ROCOVIEW provides guidelines for choosing the right monitor for the right job. As mentioned before, weighing ALL factors, the best all purpose monitor for the Radiologist who dictates all modalities is the grayscale 3 megapixel monitor and the best all purpose monitor for the Clinician who reviews ALL modalities is the color 2 megapixel monitor.
There is overlap in resolution suggestions owing to experience and comfort level of the reader. ROCOVIEW recommends:
5.2MP:
? mammography
? plain film (diagnostic)
? 512x512 pixel cross sectional imaging (CT, MR) displayed on 20 on 1 or less.
3.1MP
? mammography
? plain film (diagnostic?)
? 512x512 pixel cross sectional imaging (CT, MR) displayed on 12 on 1 or less.
? ultrasound
? nuclear medicine
1.9MP
? plain film (review)
? 512x512 pixel cross sectional imaging (CT, MR) displayed on 6 on 1 or less.
? ultrasound
? nuclear medicine
1.3MP or 0.79MP
? 512x512 pixel cross sectional imaging (CT, MR) displayed on 2 on 1 or less.
? ultrasound
? nuclear medicine
Greg Rose, MD, PhD
