When communicating diagnoses and determining the best treatments for patients, the ability to produce quality imaging through the use of technologies such as x-ray, ultrasound, magnetic resonance imaging (MRI), and tomography is essential. These devices allow for radiologists and clinicians to visualize the physical and functional attributes of a patient to help make optimal medical determinations. Therefore, the image quality garnered from these devices must be strictly controlled to ensure clear and consistent imaging.
In the past, medical imaging was achieved through the use of hard-copy film and the quality of those images was controlled during the image exposure and development stages. However, now with the advent of the digital imaging system, image quality is mostly dependent on the characteristics and attributes of the electronic displays themselves.
Therefore, it is imperative that medical professionals understand the requirements necessary when selecting the best medical monitor/display for their practice.
Requirements for Medical Imaging and Displays
Requirement 1: Luminance level greater than 400 cd/mº
The majority of displays used in medical imaging utilize liquid crystal displays (LCDs), backlit either cold-cathode fluorescent lamps (CCFLs) or light-emitting diodes (LEDs). The capabilities of the luminance system of an LCD are dependent upon their backlight system.
Luminance is critical to the medical imaging process as poor luminance can have a negative impact on diagnostic accuracy. If a display is too dim, then the differences between shades of gray can be diminished. A radiology image contains up to 256 shades of gray that must be distinguishable to a doctor’s eye, therefore the imaging must offer sufficient luminance to create those perceptible shades.
Furthermore, displays must be able to achieve the correct brightness output immediately while also maintaining the ability to sustain desirable luminance over time.
To achieve the desired luminance, a level greater than 400cd/mº is recommended. Commercial grade monitors tend to range from 200-300cd/mº and therefore, the use of medical specific displays allows for better viewing.
Requirement 2: Gamma Correction
Gamma is an indicator that describes the nonlinear relationship between the numerical value of a pixel and the luminance output of the display. Gamma correction is therefore utilized to bridge the difference between the linear representation of light intensities and the nonlinear response of the human eye.
Most medical and commercial displays integrate a native gamma approximate, the ability to automatically gamma correct, which is vital for ensuring accurate diagnoses.
Requirement 3: DICOM Grayscale Compliance
The Digital Imaging and Communications in Medicine, (DICOM) grayscale standard display function (GSDF) provides a quantitative mechanism for mapping digital image values into a range of luminance values and serves as the standard for displaying grayscale medical images. The DICOM GSDF curve has also been specifically calibrated to take into account how the human visual system perceives luminance and changes in contrast.
For optimal medical imaging, displays must be equipped with luminance stabilization and calibration technology to maintain grayscale characteristics that consistently conform to DICOM GSDF specifications.
Requirement 4: Compatibility with Legacy Equipment
Medical devices do not operate in isolation; rather they are integrated and interconnected amongst various pieces of medical equipment to achieve optimal efficiencies. Further, healthcare providers seek to invest in innovative, high-performance, low-cost technologies with a long-lifecycle.
Therefore, it is necessary that medical displays support legacy interfaces such as VGA and S-Video, as well as more modern updates such as HDMI and DisplayPort, to create compliance amongst as wide a range of devices as possible.
Additionally, medical displays must feature high- capacity ports to facilitate data transmissions with minimal latency, especially when presenting 4k resolution images and videos.
Requirement 5: Advanced Medical Grade Imaging through Color Capabilities
Medical imaging largely operates in monochrome; however, color monitors are being employed at an increasing rate due to economic considerations. However, the use of color displays for grayscale imaging applications requires testing for consistent and accurate presentation.
Color displays tend to color drift, which must then be corrected through the use of color calibration. Therefore, monitors with the ability to support color correcting and calibration procedures is vital to ensuing efficient and accurate diagnoses.
Why Optimal Medical Imaging Matters
High-resolution imaging and detection technologies bring a range of advantages to a medical practice as they enable precise and timely diagnoses while also serving as an effective support for preventive care measures. Because image consistency is vital to such a wide range of medical applications, every effort must, therefore, be made to optimize displays.
By keeping these requirements in mind when determining which medical display device is correct for your practice or clinic, you will be ensuring that you have built a situation where healthcare can be provided effectively, consistently and efficiently.
