Masaya Takahashi, Ph.D.
Masaya Takahashi, Ph.D., is developing analytical methods that overcome one of the most difficult challenges in MRI: imaging the lung. The lung is in constant motion, and its large air-filled volume severely attenuates MRI signals. However, Dr. Takahashi's techniques will enable MRI to become a standard tool for accurately diagnosing emphysema and fibrosis—scarring of the lung tissue from infection, autoimmune disorder, or other injury. They will also enable MRI to assess lung function in pulmonary embolism, pulmonary hypertension, lung transplantation, and lung cancer. And, his techniques will enable assessment of the response of these disorders to drugs and other treatments.
For one thing, MRI can offer a more detailed map of lung function. Also, MRI is more desirable for repeated lung scans, necessary because of the slow progression of lung disease, because it does not involve radiation exposure, as do CT scans. As the technology of CT scans has advanced for lung imaging, enabling larger volume of coverage with higher resolution and lower noise, these advances have led to increased radiation exposure.
Dr. Takahashi is recently using a technique called ultrashort echo time (UTE) MRI to obtain detailed images revealing tissue density in the lung parenchyma, the alveoli, and other structures involved in respiration. The technique can produce the MRI signal from tissues in the lung, and enables lung imaging.
He has applied UTE in animal studies comparing normal mice and those with emphysema. These experiments showed that it is possible to identify and pinpoint localized regions of lung damage. Such precision is important because current tests of pulmonary function yield only a global assessment of lung function. Those tests involve asking a subject to inhale and exhale air, and using resulting volume and pressure measurements as an indicator of lung function. Thus, such tests cannot show localized damage and may indicate that a lung is functioning normally when it is actually developing localized pathological changes due to emphysema.
Dr. Takahashi is also using UTE to analyze the distribution of ventilation/perfusion, the circulation of air and blood, in the lung. In ventilation studies subjects inhale oxygen, and in perfusion studies, the MRI contrast agent gadolinium is injected to reveal blood circulation.
Such diagnostic advances could enable MRI to replace scintigraphy, the only currently available technique to measure ventilation/perfusion. This method is invasive because it requires an inhaled or injected radioactive isotope and provides very poor spatial resolution.
For publication information please view Dr. Takahashi's faculty profile.