June 25, 2019
Mayo Clinic uses 7-tesla MRI for enhanced visualization of cerebral cavernous malformations, facilitating optimal management of these vascular abnormalities.
"The 7-tesla magnet gives us significantly greater definition of a cavernous malformation. We are able to better understand the anomalous venous structures often associated with a malformation ― which are probably, in many cases, the malformation's cause," says Giuseppe Lanzino, M.D., a neurosurgeon at Mayo Clinic in Rochester, Minnesota.
Mayo Clinic was the first center in North America to adopt clinical 7-tesla MRI. The advanced imaging technology augments Mayo Clinic's expertise with this complex condition, aiding the diagnosis and decision about whether a cavernous malformation should be surgically removed to prevent bleeding.
"Cavernous malformations are challenging because there's often a substantial risk of bleeding — but also risks associated with surgical removal, especially when malformations are located in highly eloquent areas of the brain," says Kelly D. Flemming, M.D., a neurologist at Mayo Clinic's campus in Minnesota. "We have a multidisciplinary team with experience in the natural history of cavernous malformations that works together to evaluate the risks and determine a management strategy."
A designated Center of Excellence
Mayo Clinic is one of six centers in the United States designated as a Center of Excellence for cavernous malformation treatment and research by the Angioma Alliance, a patient advocacy group. As a fully integrated center, Mayo Clinic coordinates appointments across specialties. "Usually, a patient can have all the imaging and consultations done and receive a treatment plan within two days," Dr. Flemming says.
Patients with cavernous malformations are often young adults or sometimes children. A malformation might be asymptomatic and found incidentally, or a patient might present with bleeding, focal neurological deficits, headaches or seizures. "These seizures can be quite difficult to control with medication. That might be an indication for surgery," Dr. Lanzino says.
Cavernous malformations have a less than 2% annual risk of clinically significant hemorrhage. However, once a patient experiences a hemorrhage, there is a 30% to 50% chance of recurrent bleeding or a focal neurological deficit within five years, depending on the location of the cavernous malformation. As yet there are no known risk factors that a patient can modify to prevent future hemorrhage.
Yet the decision whether to resect a cavernous malformation that has bled isn't necessarily straightforward. "There are a lot of misconceptions about cavernous malformations," Dr. Lanzino says. "Although the risk of another bleed is fairly substantial, it's also true that when a cavernous malformation bleeds, the surrounding tissue is often displaced rather than permanently damaged. Patients often improve on their own without any additional treatment, while remaining at substantial risk of additional hemorrhage."
At Mayo Clinic, decisions about the management of a cavernous malformation are made on an individual basis. In addition to subspecialized neurologists, the multidisciplinary treatment team includes experts in neuroradiology, stereotactic radiosurgery and open neurological surgery.
"Very particular trajectories and approaches are necessary to reach cavernous malformations, while minimizing as much as possible the risk of damage to surrounding tissue," Dr. Lanzino says. "Our surgeons are well experienced with these various approaches. We also have significant experience with cavernous malformations in areas where lesions were once considered inoperable — such as the brainstem and thalamus — with very good results."
Dr. Lanzino notes that at Mayo Clinic, most patients who present with seizures experience better seizure control after resection of a cavernous malformation. "A significant percentage of these patients can potentially discontinue medication after being seizure-free for one to two years after surgery," he says.
Future treatment options
Mayo Clinic is at the forefront of cavernous malformations research. Mayo researchers have published outcome research on 292 patients and have now enrolled 250 additional patients in the Mayo Clinic Cavernous Malformation Prospective Registry, an effort to learn more about the condition's natural history.
Mayo Clinic is also part of a multicenter effort to develop the infrastructure for clinical trials of new therapeutics to help patients who aren't eligible for surgical resection.
"There are now potentially five or six medications coming to clinical trial in the next three to five years. That was unheard of, even five years ago," Dr. Flemming says. "It's pretty exciting that there may be candidate medications for people who don't want or can't have surgery but also don't want the risk of bleeding from a cavernous malformation."
"We have made a lot of progress in the past 20 years with cavernous malformations, in terms not only of imaging and diagnosis but also of understanding the natural history and indications for treatment," Dr. Lanzino adds. "We bring that experience, and our commitment to the best possible care for our patients."