AD5791 data conversion improves MRI image quality

MRI (magnetic resonance imaging) scans provide exceptionally clear images of the human body and are commonly used to diagnose a wide range of diseases and injuries, including Alzheimer's disease, tumors, and torn ligaments. Analog Devices, Inc., a leading global provider of data conversion technology and a long-time collaborator with the medical imaging industry, has announced a breakthrough in data conversion that will help provide clinicians and radiologists with ultra-sharp images, helping them see smaller anatomical structures and lesions, such as breast cancer cells, than ever before.

ADI's AD5791 high-precision 20-bit digital-to-analog converter (DAC) is the industry's first DAC device with true 1ppm (one millionth) resolution and accuracy, which is 4 times higher than similar converters. 1ppm analog system design usually faces complex engineering challenges, requiring the integration of multiple lower-resolution DACs and a large number of discrete components with supporting ICs, accompanied by considerable development risks and costly modification time to optimize circuit parameters, reduce errors, and design complex automatic calibration circuits. The AD5791 has 1ppm resolution and accuracy, low noise (less than 1ppm), fast refresh rate (1us) and very low output drift (less than 1ppm), which can greatly simplify design tasks, reduce development costs and reduce risks.

In MRI systems, this breakthrough technology not only improves image quality, but also allows precise control of magnetic gradients in high magnetic field strength applications, thereby achieving ultra-high image resolution and contrast. The use of the low-noise, low-drift, and high-linearity AD5791 eliminates the need for frequent offline MRI systems due to system calibration cycles, effectively extending the working time of the MRI system. The new converter also reduces the need for complex calibration algorithms, thereby reducing engineering and system maintenance costs. In addition to MRI systems, other applications suitable for the AD5791 include test and measurement systems, high-end scientific and aviation instruments, communications equipment, and industrial control systems.

Enhanced data conversion performance can help imaging system designers improve image clarity and speed up the diagnosis of early-stage diseases by doctors, thus enabling timely treatment. The AD5791 DAC provides exceptionally low noise performance, reducing image artifacts, thereby reducing the need for multiple MRI scans. In addition, lower image error rates and higher reliability can ensure that more patients can be treated efficiently in a shorter time.

More than 60 million MRI examinations are performed worldwide each year. MRI is a non-invasive technique that does not require the use of ionizing radiation to obtain images of the body, making it ideal for diagnosing a wide range of injuries and conditions, and the examination can be tailored to meet specific imaging parameters (such as the area of ​​interest).

“The AD5791 sets a new benchmark for image clarity, resolution, and contrast in medical imaging systems – system design requirements necessary to ensure radiologists can quickly and accurately diagnose patients,” said Patrick O’Doherty, vice president of the Healthcare Division at Analog Devices. “For system architects, the 1ppm performance level enables a monolithic DAC architecture that can effectively reduce design size and cost. This means that for the first time, designers have the opportunity to free up a large portion of the system error budget, saving resources that can be used for critical components in other subsystems or improving overall MRI performance.”

The 20-bit AD5791 provides a relative accuracy of ±1 LSB at maximum, and can guarantee monotonic output at a maximum DNL of ±1 LSB. The AD5791 has a low-frequency noise of 0.025ppm and an output drift of 0.05ppm/C. The output range can be configured as a standard unipolar (+5V, +10V) or bipolar (±5V, ±10V) voltage. The AD5791 uses a universal three-wire serial interface with an operating clock rate of up to 50MHz.

The AD5791 DAC is the latest example of ADI providing leading-edge technology for medical imaging systems. Other recently released medical devices from ADI include the ADAS1128 24-bit current-to-digital converter, the ADuM4160 single-chip USB isolator (Universal Serial Bus Isolator), and the AD927x family of 8-channel receive front ends for ultrasound systems. These products, along with our other devices, represent the broadest portfolio of ICs developed today specifically for the healthcare imaging market.

With the aging of China's population, the improvement of medical conditions, and the Chinese government's large-scale investment in the healthcare industry, the demand for China's electronic medical market, especially the high-end medical electronics market, continues to grow. The strong demand for high-end medical equipment for hospitals and professional medical institutions, including computed tomography (CT), magnetic resonance imaging (MRI), X-ray equipment, etc., is bound to bring about further development and prosperity of medical electronic technology. For the high-end medical equipment market, leading foreign medical device suppliers are now also facing competition and pursuit from local companies. Improving the R&D capabilities of the Chinese market by setting up R&D centers in China and introducing outstanding talents is an advantage in maintaining competitiveness. As a leading supplier in the field of medical electronics, ADI will always adhere to the fundamental goal of improving people's lives and is committed to providing excellent Chinese medical IC products and services.

Recommended supporting devices

Devices used in conjunction with the AD5791 include: AD8276 and ADA4004-x series operational amplifiers, ADP3331 regulators, ADP1864DC/DC step-down controllers, and ADP121 linear regulators.