AVIATOR Project at UCSF Aims to Simplify HHT Imaging
Hemorrhagic telangiectasia (HHT) is a genetic disorder that leads to abnormal blood vessel formation in the brain, lungs, liver, and other organs. During HHT Awareness Month, UCSF is highlighting the work of Steven Hetts, MD, chief of interventional neuroradiology and principal investigator of the AVIATOR Project, a study designed to simplify and improve imaging for patients with HHT.
The AVIATOR Project, which stands for Efficient and Comprehensive Advanced Magnetic Resonance Imaging of Hereditary Hemorrhagic Telangiectasia Vascular Malformations, aims to simplify and improve screening for AVMs (arteriovenous malformations) in patients with HHT. As Dr. Hetts explains, "The AVIATOR Project is an effort that we put together at UCSF to develop a more comprehensive MRI examination that can evaluate the brain, lungs, and liver, all in one scan."
From Multiple Tests to One Comprehensive Scan
Currently, HHT patients may need separate imaging tests—brain MRI, chest CT or bubble echocardiogram, and liver ultrasound—to detect and monitor vascular malformations. Dr. Hetts and his team are working toward replacing this fragmented process with a single, noninvasive MRI scan. "This approach could be more convenient for patients and allow us to better track changes over time, as we track the treatment of these vascular malformations," he notes.
Since receiving the AVIATOR grant, the UCSF team has scanned about 35 patients. Early results look promising. "The lesions are very well identified on the MRI, and that's a real plus because this could substitute for the CT of the chest, which involves x-ray radiation," Dr. Hetts notes. "We're starting to be able to see some of the internal structure in the vascular malformations in the brain that previously could only be seen with the catheter angiogram."
Leveraging Ferumoxytol and 4D Flow MRI
Ferumoxytol, an FDA-approved iron replacement, plays a central role in the AVIATOR scans. "It allows us to get really high-resolution pictures of vascular malformations," says Dr. Hetts. In the lungs, this enables detection of AVMs as small as two millimeters, which is an important threshold for treatment decisions. In the liver, 4D flow MRI is helping track how AVMs affect blood flow, which can guide treatment to prevent heart failure.
A Closer Look at Brain AVMS with 7T MRI
The study also included high-resolution 7T MRI to visualize brain AVMs in more detail. "It's starting to allow us to see features that previously we could only see on a catheter angiogram," shares Dr. Hetts. These include aneurysms and venous outflow stenoses, which help assess bleeding risk. The goal is to make it possible to monitor these lesions without invasive procedures.
Building Toward a New Standard
Looking forward, Dr. Hetts and his team hope to recruit 162 participants to validate the MRI protocols and build what he calls a "global HHT disease burden score." This would quantify a patient's condition based on the number and severity of AVMs across multiple organs. Ultimately, Dr. Hetts envisions this MRI protocol being used at other HHT centers worldwide. "Our hope is that by the end of the study, we can say this ferumoxytol-based MRI technique is deployable."
"Can we combine those into a score, one point, three points, seven points, on a consistent scale of severity?" Dr. Hetts proposes. Such a tool could enable clinicians to measure disease progression and treatment response with greater precision.
For families with a history of HHT, early genetic testing and imaging are crucial, even in the absence of symptoms. Early identification allows clinicians to intervene before serious complications arise.
Participation and Access
UCSF's HHT Center of Excellence, certified for over a decade, welcomes participation in the AVIATOR study. "It's open to everyone," shares Dr. Hetts. "The more people who take part, the faster we'll get answers."
As HHT Awareness Month continues, UCSF encourages patients and families to seek expert care, get screened early, and consider joining research efforts like the AVIATOR study. Your involvement could help improve care for others down the line.