Neuro Imaging

Non-Invasive Optimal Vessel Analysis at Santa Barbara Neuroscience Institute



Sean Snodgress, MD

The VasSol Non-invasive Optimal Vessel Analysis (NOVA) system is the latest addition to the diagnostic imaging repertoire available at Santa Barbara Neuroscience Institute at Cottage Health System. This technique, which was brought online at SBNI in October 2009, is changing the way physicians diagnose and treat neurovascular conditions.

•    Director's Letter
•    NOVA
•    Schwannoma Case
•    Chiari Malformations
•    Neuroscience at UCSB
•    Neurogenic Thoracic Outlet Syndrome
  PFO Closure Device

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NOVA is performed at Cottage as a complement to magnetic resonance (MR) angiography and is used primarily to evaluate the arteries that deliver blood flow to the brain. The additional information NOVA provides allows physicians to better triage patients with a variety of diseases affecting these vessels.


“MR, CT [computed tomography] and conventional angiography all provide valuable information about the arteries that supply blood flow to the brain; however, these technologies have their limitations,” says Sean Snodgress, MD, one of the neuroradiologists at the Cottage Center for Advanced imaging. “Angiographic techniques outline anatomy and allow us to estimate the caliber of a stenosis or define the location and morphology of an aneurysm. However, NOVA is the only technique that allows us to quantify blood flow within a vessel. NOVA tells us not only that there is a stenosis, but how much that stenosis is impacting the flow of blood to the brain.”


NOVA combines time-of-flight MR acquisitions with MR angiography to provide a detailed snapshot of the arterial circulation, indicating flow volumes and directions on each of the major vessels. NOVA generates a report consisting of a surface rendering of vascular anatomy, a flow summary with age-matched reference values and arterial waveforms within each of the sampled vessels throughout the cardiac cycle. The technology is non-invasive, involves no radiation exposure and can be performed without the use of intra-venous contrast material.


Following standard magnetic resonance (MR) angiography, the vessels to be evaluation for non-invasive optimal Vessel Analysis (NOVA) flow volume analysis are chosen and subsequently indicated on images such as this one. Here, the basilar artery is evaluated with the region of interest indicated in yellow and an adjacent arrow denoting the direction of flow in the vessel. the flow volume through that vessel is calculated  using phase contrast techniques and tabulated in chart form for analysis. 


Manifold Uses for NOVA

NOVA technology assists in the evaluation of patients with carotid stenosis.


“With NOVA results, we can determine if a patient needs medication or surgical intervention, such as intracranial stenting,” says Alois Zauner, MD, neurosurgeon and neurointerventionalist at Santa Barbara Neuroscience Institute.


In addition, NOVA provides a non-invasive technique for determining the continuing effectiveness of a stent.

“One of the situations in which I find NOVA most helpful is with patients who have already undergone stenting,” says Dr. Snodgress. “evaluation for a recur- rent in-stent stenosis is very difficult utilizing CT or MR angiography because of the imaging artifacts the stents create. NOVA allows us to quantify the flow passing through the stented vessel, and for the first time we have a noninvasive technique that tells us whether the stent is still doing its job.”


Potential Applications

NOVA analysis is not limited to neurovascular imaging.




“Non-invasive optimal vessel analysis enables us to make precise decisions, which precludes the use of invasive procedures in the diagnosis of intracranial and vascular diseases, a benefit for patients and clinicians.”

—Alois Zauner, MD, neurosurgeon and neurointerventionalist
Santa Barbara Neuroscience Institute at Cottage Health System


“This system can evaluate flow within most of the arteries in the body,” says Dr. Snodgress. “For example, NOVA could be used to assess blood flow in the renal arteries in hypertensive patients or to quantify flow in the arteries of the lower extremities in patients with claudication.” 


Access to Advanced Technology

The Cottage Center for Advanced imaging is the only facility in the area with NOVA capabilities.


“NOVA enables us to make precise decisions, which preclude the use of invasive procedures in the diagnosis of intracranial vascular diseases, a benefit for both patients and clinicians,” says Dr. Zauner.


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