Color My World: A Look at Color Displays

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Not too long ago, hospitals began to recognize the importance of digitizing their workflow.  They found it could save money, increase profits, and quicken diagnosis time by investing in hospital information systems, picture archiving and communications systems and electronic medical record systems. Color monitors and displays were mainly purchased for hospitals viewing stations. They were found to be esthetically pleasing when viewing EMR, HIS, and patient data; and monochrome displays could be found in diagnostic imaging to be used in conjunction with PACS. However, now color displays are now coming out of the back office and becoming highly useful tools in viewing diagnostic and even therapeutic images.

The use of color in medical imaging has proven to be highly effective and more widespread in the United States today. Companies such as Barco, Planar Systems, Siemens Display Technologies, NEC Display Solutions of America and Eizo Nanao Technologies have introduced color LCD monitors and projectors that are utilized across a variety of clinical specialties. These companies, along with others, recognized that the need for a variety of color displays was necessary to advance healthcare technology.

Defining color displays

There are two main types of color displays used today in the healthcare arena: medical grade and consumer grade. Medical grade color displays are most often purchased by hospitals for modalities such a nuclear medicine, computed tomography, positron emission tomography, ultrasound and magnetic resonance imaging as well as viewing images in cardiology. These medical grade color displays have a higher megapixel count, as opposed to their consumer grade counterparts. "Our facilities typically use three megapixel displays for diagnostic imaging and two megapixel displays for tech images," says Margery Sandner, PACS administrator for Sutter Health of Central Valley, Calif. Margery says that they have been implementing NEC monitors for applications such as nuclear medicine, ultrasound and cardiology in their organizations since 2004 and have found their use irreplaceable.

Hospitals also purchase consumer grade color monitors with a smaller megapixel count for back office environments for web browsing, patient data look ups, or reviewing EMRs. Color displays have proven to be versatile and can be used with a wide array of other technologies, including PACS, patient monitoring, EMR, HIS and RIS.

Monochrome vs. color

Most hospitals in the United States continue to use grayscale displays for the majority of image viewing. Grayscale displays have been the mainstay due to their higher pixel counts. Color displays range between one and three megapixels while their grayscale cousins can go up to five. As a result, the contrast is sharper and the brightness is greater.

Few color medical displays have DICOM compatibility with the ability to display eight bits of grayscale per color (16 million colors). These displays usually come with a brightness of 400 cd/m2 and a typical contrast ratio of 400:1. Grayscale is currently leading the race in gradation smoothness and sharpness.

Because of this smoother gradation and better visibility, it is currently standard that mammography exams and most radiology exams, if digitized, must utilize grayscale display for diagnosis. However, color displays are being implemented for a wide array of uses today not only for viewing of patient and EMR data, but also for diagnostic procedures.

"The radiologists think that digital imaging used in conjunction with color displays is the way to go," says Sandner. "The color displays have made it easier to diagnose problems in areas such as ultrasound and nuclear medicine. For the procedures that involve cardiac patients, the diagnoses are easier to determine due to the ease of viewing with the color displays."

Grayscale monitors are predominantly used with modalities such as x-ray and mammography. Cancerous cells are easier to detect and more clearly seen using grayscale monitors. However, color displays are highly effective for CT, nuclear medicine, and other modalities that find 3D images with color increase the ease of diagnosing pathological issues that would be much harder to detect if using grayscale or manual film imaging.

Eizo's RadiForce Products are examples of color monitors that enable both accurate color and grayscale gradations that can be used by modalities such as MRI and PET and also utilize 3D image rendering.

Though most hospitals that implement color displays utilize this technology in nuclear medicine, CT, MRI, and other imaging modalities, their use is growing in the healthcare industry. As computer assisted detection (CAD) is adopted, color displays often enhance visualization. Pathology and dermatology applications are other areas that greatly benefit from the use of color displays and monitors. In addition, virtual colonoscopy can provide a great opportunity to use color to assist in diagnosing potential problems. Many in the industry believe that as software rendering capabilities increase, more studies will require a color display to take advantage of the many features of software.

Some technologies that are being introduced can incorporate both color and grayscale views. Take for example Barco's Color Coronis 2 megapixel product - it is a diagnostic quality color monitor that is optimized for both color and grayscale images. It features an integrated I-Guard sensor for automatic DICOM compliance and intervention-free calibration. This technology saves hospitals from purchasing additional color displays. Some of its other features include smooth and speedy 3D operations for CT, MRI and PET, In-Plane Switching (IPS) technology which makes it easier for additional viewers to assist in diagnosis from different angles.

Planar also has products that offer assistance to hospitals looking to use color displays. Planar's Dome line offers a wide range of color products from one to three megapixels that are DICOM calibrated and can be used for teleradiology. In addition, the displays can be mounted to mobile carts in the case of Dome Surgery Review Cart for the operating room and emergency room. Planar's products have been well accepted in the industry for their performance and ability to maintain quality assurance. The monitors are DICOM calibrated with Dome CXtra software and can be remotely monitored for QA purposes with Dome Dashboard software.

Color displays also can be used as embedded monitors in other medical instruments and surgical devices. These color displays are designed to act on video signals that can be used in areas such as arthroscopy. These custom-designed color displays combine both mobility and high- quality viewing features. Planar's Dome Surgery Review Cart provides this capability.

Pros and Cons

There are few cons to implementing color displays in the healthcare field. As mentioned before, there is currently limited benefit for color monitors in digital x-ray and mammography. In addition, color coding may be confusing to some radiologists who have limited or no exposure to digital images.

The pros of utilizing color display continue to flourish and grow. Hospitals find that color contrasting has been developed which further increases understanding and reduces medical diagnosis time. Examples are Siemens SHD 17100 and SCD 18980 color display solutions. Each has microprocessor controls built into the internal memory to provide high contrast even in the brightest ambient light conditions. The products also have a backlight control circuit for constant screen luminance.

Color coding also is a feature of color displays that proves versatile. It can be used in CT image rendering to identify various types of tissue. In nuclear medicine, it can be used to highlight a target tissue that is sensed by a detector. Color coding can be used to indicate blood flow in ultrasound. Using color displays enables multi-modality readings on the same display thus decreasing the initial investment.

In radiology, color displays have been used as a third monitor, used in conjunction with two grayscale diagnostic displays - to view patient and EMR data. Also, the need for digital imaging in other hospital areas is increasing. More and more displays are being found in areas such as outpatient surgery and operating rooms as they improve surgical turnaround time and make it easier to diagnose medical issues. Lastly, many believe that color will be used in the future with digital x-rays and mammography for digital annotation purposes.