Researchers at Brigham and Women’s Hospital (BWH) have produced the first-ever magnetic resonance images (MRI) of the human lungs’ airways using hyperpolarized helium gas. This highly innovative imaging method, known as dynamic hyperpolarized helium MRI (HP noble gas MRI), set to be tested in a clinical trial, allows physicians to view the inner structure of the airways in exquisite detail, effectively unlocking the mysteries of lung function that have long eluded physicians. The findings will appear in the May issue of the journal Radiology.
“We have developed a noninvasive and safe technique that produces clear and accurate three-dimensional (3-D) images of the airway tree,” said Mitchell Albert, director of the Hyperpolarized Noble Gas MRI Laboratory at BWH. “With this new technology, clinicians can finally visualize how the airways work, rather than resort to scientific speculation.”
Currently, physicians must make educated guesses about what severe constricting lung conditions such as asthma actually look like. Without a way to view airway structure and function in real time, clinicians have reached diagnoses and prescribed therapies often with little more data than what an X-ray may show or what they may hear through the stethoscope. However, HP noble gas MRI, a cost-effective technology that does not subject patients to harmful radiation, has the potential to rapidly advance diagnosis and treatment. This theory will be tested as Albert and his team of researchers probe into the airway structure and function of asthma patients in the first such clinical investigation of its kind.
“We have an exciting opportunity to help physicians diagnose pulmonary disorders and more importantly, measure the efficacy of the drug therapies being used to treat them,” said Albert. “Prior to the development of this technique, physicians used their best predictive models to estimate how the airways were influenced by medications. Now we can document the progress patients are making. We also expect our findings to drive the development of new and more effective pulmonary medications.”
Albert first experimented with hyperpolarized noble gas in 1992 and is credited with being one of the researchers who conceptualized its role in diagnostic imaging.
According to Albert, assistant professor of radiology at the Harvard Medical School, HP noble gas MRI can be readily adapted to current MRI technology. “Most standard MRI machines can be converted to receive a helium signal,” he said. “It is a technique that can be easily replicated at a low cost.”
Moreover, HP noble gas MRI offers a safe imaging alternative for children and the elderly, who should not be exposed unnecessarily to radiation. The safety afforded by HP noble gas MRI should serve as additional incentive for using this technology to treat diseases such as asthma and cystic fibrosis – conditions that may cause patients to undergo a high volume of scans on a regular basis, noted Albert.
Albert’s research is based on findings from six adult subjects who inhaled one bag (approximately half a liter) of hyperpolarized helium for about seven seconds and underwent MRI scanning during the inhalation. The team has successfully developed specialized techniques and precision instruments for both hyperpolarizing the gas and for reading the signals sent by the helium. In applying these technologies, Albert is credited for generating dynamic images of up to the seventh generation airways, the most distant airways from the trachea ever documented in humans by MRI.
With the potential to become another important diagnostic tool in the detection and treatment of lung disease, which is the fifth greatest cause of morbidity and mortality in the United States, the technique may also have other low risk, high benefit applications such as identifying signs of organ rejection following lung transplant surgery.