Towards the Early Diagnosis of Dementia using MRI
Major advancements in Hitachi’s MRI-based sophisticated data analytics have enabled the application of quantitative measuring to diagnostics, which has demonstrated potential in the early detection of dementia and other brain-related diseases. Potential applications in the early diagnosis of diseases of the brain, such as dementia, which have traditionally been difficult to detect.
Left: Open MRI with a more spacious examination environment
Right: Oval MRI with enlarged space for the patient while scanning
MRI systems use magnetism and radio waves to image blood vessels and other organs. Essential diagnostic tools in healthcare, the machines are recognized as being particularly suited to diagnosis involving the spinal cord or brain matter inside the skull. Unfortunately, many people develop an aversion to the machine even after experiencing just one MRI scan due to the sense of claustrophobia that comes from spending twenty to forty minutes inside the machine’s cylindrical interior and being exposed to the distinctive, loud sounds it makes while scanning.to
During development, Hitachi places a high priority on making its MRI systems easy on patients. The outcomes of this work include an open MRI design that provides patients with a greater sense of space while undergoing a scan, and an oval-shaped MRI that provides a larger scanning space to reduce the feeling of claustrophobia.
MRI equipped with the latest technology for quiet operation, which reduces noise by 94%
Hitachi has also succeeded in developing an MRI machine that makes 94% less noise during a scan (compared to previous Hitachi models) without compromising high image quality. This helps provide a low-stress environment for the patient being scanned.
Image quality also has been improved. A combination of sophisticated data analyses made while scanning can identify subtle changes in tissue that would have gone undetected in the past. MRI is also recognized as having the potential to aid the diagnosis of psychiatric and neurological diseases such as dementia in the future.
Japan's Ministry of Health, Labour and Welfare estimates that approximately seven million people in the country will suffer from dementia by 2025. If those suffering from mild cognitive impairment (MCI), an early stage of dementia, are included, this number swells to around 13 million*1. This equates to a startling one-in-five members of the population 65 years and older. Alzheimer's disease accounts for 60% of these dementia cases, but if detected early, the use of medication and other treatments is believed to slow the progression of its symptoms. Moreover, MRI has become one of the diagnostic imaging techniques used for this purpose.
*1: Based on figures from the Ministry of Health, Labour and Welfare.
The causes of Alzheimer's disease and other forms of dementia are believed to include degeneration of the brain and abnormalities in cerebral blood flow. Although physicians can identify these by augmenting consultations with the examination of MRI images or similar, they find it extremely difficult to differentiate from conditions such as depression, and to determine which of the various types of dementia is present. This calls for more precise images and objective diagnostic methods. To this end, Hitachi is engaged in project for early diagnosis of dementia using MRI undertaken by the Japan Agency for Medical Research and Development (AMED) in partnership with Hokkaido University.
Overview of QSM
Hokkaido University Hospital is engaged in leading-edge clinical research into the use of MRI scanning for a variety of conditions, including dementia. In particular, while published research indicates that voxel-based morphometry (VBM), a technique for assessing brain degeneration using 3D MRI images, can be used for MCI diagnosis and the early diagnosis of Alzheimer's dementia, it is difficult to establish the presence of dementia using this technique alone.
Hokkaido University and Hitachi have jointly developed a new MRI diagnostic technique called quantitative susceptibility mapping (QSM)*2 that performs a quantitative analysis of the distribution of iron concentration. It has been reported that Alzheimer's dementia is accompanied by iron deposits forming in particular regions of the brain, such as the basal ganglia and amygdala, and that these cause changes in magnetic susceptibility. This prompted the idea that a combination of QSM and VBM could provide highly precise diagnoses.
They have been developing hybrid scanning and analysis methods of QSM and VBM to realize this idea.
*2: QSM: A technique that works by analyzing changes in magnetic susceptibility due to the amount of iron or nerve fibers.
“We appreciate the extensive and comprehensive capabilities of Hitachi, which include expertise in diagnostic imaging built up over many years, and skills in simulation acquired through involvement in a variety of different businesses. Our aim is to generate new value by combining this with our own experience built up through regular interaction with patients. We are currently working to improve the accuracy of a hybrid analytical technique that utilizes both VBM and QSM so we can hasten its practical implementation. Hokkaido University and Hitachi have established a strong relationship of trust through our long history of joint medical research. By utilizing technologies from the IoT and AI, we also intend to work on establishing an environment that will enable the early discovery of previously unknown diseases.”
What advances in MRI can we expect in the future? Yoshitaka Bito, PhD, a senior chief engineer at Hitachi who has had long involvement in MRI development emphasizes the importance of quantification.
Quantification means the use of numbers to represent something that is typically thought of as only capable of being expressed qualitatively. The strength of a smell is one example, this being something that varies from person to person. Quantification is the numerical representation of subjective properties like this.
The standardization of MRI images is difficult under current practices because signal strength varies due to a variety of factors, including the site being imaged, the scanning conditions, and the machine supplier. This is a disadvantage because it introduces a degree of ambiguity into diagnostic accuracy and frustrates the use of statistical analysis in joint research across different facilities.
In response, development has included the quantification of MRI images. This quantification is aided by simulation and data analysis techniques that Hitachi has acquired and deployed across a variety of fields in the past. The quantification of MRI images not only uncovers things that could not be seen previously, but also has the potential to provide better and more consistent diagnoses and to accumulate new medical knowledge. One such example is the use of QSM for the early detection of dementia, described above.
Faster Imaging will be Crucial in the Future
The ability to perform imaging more quickly is another requirement for improving the accuracy of diagnostic imaging. An MRI scan typically takes around 20 minutes. As any movement during this time degrades image quality, patients are obliged to remain completely still, something they find very stressful. In response, Hitachi has developed a technique for shortening the scan time to about five minutes without compromising quantitative performance. The advantages of this are that it avoids image degradation due to patient movement while also shortening the waiting time for patients undergoing a scan.
MRI is based on extremely advanced and complex technology that still has many unknowns. So, while uncertainties exist, there is also scope for further development. In the future, Hitachi intends to continue contributing to the progress of healthcare by engaging in collaborative creation with partners to make further improvements in diagnostic imaging.