Volume CT: The Key to a Superior Stroke Protocol

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Sponsored by an educational grant from Toshiba America Medical Systems

Over the last year, Kaleida Health Stroke Center at Millard Fillmore Gates Circle Hospital in Buffalo, N.Y., a national leader in stroke care, revised its stroke protocol with 320 detector row CT to better inform and accelerate clinical decision-making and optimize patient care. The goal is to individualize stroke care by carefully selecting patients for treatment. “Imaging is key,” says Kenneth Snyder, MD, PhD, senior endovascular fellow.

The state-of-the-art foundation for the hospital’s stroke protocol is the Aquilion ONE dynamic volume CT scanner from Toshiba America Medical Systems. The dynamic volume CT solution images the entire brain and shows real-time brain function with greater detail and in less time than conventional MR or 64-slice CT imaging systems.

“The ability to better inform and accelerate clinical decision-making is especially important in stroke patients,” says Michael Miller, MD. “Time is brain. Saving even 15 minutes in the lead time to diagnosis can make a significant difference in clinical decision-making and guide patient treatment, which impacts outcomes.” In addition, the dynamic volume solution provides a whole-brain perfusion map. The complete dataset helps physicians better select patients for treatment and removes artificial time constraints. The new protocol represents a giant step forward for the stroke center, which is one of a handful of centers nationwide to earn the Gold Seal of Approval and Disease-Specific Care Certification for Acute Stroke from the Joint Commission on Accreditation of Healthcare Organizations.

Aquilion ONE provides additional benefits as well. Image quality can surpass MRI and 64-slice CT in acute stroke patients, many of whom are confused, agitated and moving continuously. In addition, the volume acquisition mode allows sub-second routine brain imaging, which can minimize motion artifact on some sequences. Aquilion ONE whole-brain volume perfusion imaging allows evaluation of blood supply to the entire brain that is not possible on conventional helical scanners, in much less time and with fewer artifacts than MR perfusion.

Developing the new Aquilion ONE protocol required the commitment and collaboration of a multi-disciplinary team of radiologists, clinicians, technologists, nurses and IT personnel, backed by a strong partnership of Kaleida Health System, Toshiba and its workstation partner Vital Images. The end benefits—improved and accelerated decision-making and better informed treatment—demonstrate the value of the Aquilion ONE Neuro One acute stroke protocol.

The challenges of conventional stroke imaging

When Millard Fillmore Hospital opened the Kaleida Health Stroke Center, physicians relied on MRI, MRA and MRP to diagnose strokes. The first-generation acute stroke imaging protocol consisted of a limited brain MRI, MR perfusion and MR angiography of head and neck vessels, and it required gadolinium contrast agents. These techniques presented several challenges. 

The first challenge was time.  After months of tweaking, the optimized MR protocol required about 15 to 20 minutes to complete—after appropriate magnetic environment safety screening. “Patients must be screened prior to MR imaging for the presence of foreign bodies, aneurysm clips and pacemakers,” explains Miller. Patients who could not provide an immediate history were subjected to a pre-MRI screening protocol that included x-rays of the skull, neck, chest, abdomen and pelvis to ensure a safe MR scan. Screening the typical stroke patient who presents to the ER confused, aphasic, comatose or otherwise unable to give a history is not only challenging but also adds time to the diagnostic process. “X-ray imaging and interpretation might add as much as 15 to 20 minutes to the process,” shares Miller.

The second challenge also related to time. Individual MR series entail a fairly lengthy acquisition time. Consequently, studies are prone to motion artifacts that can degrade diagnostic value and accuracy. One way to reduce motion artifacts is to use conscious sedation in the MR suite for agitated patients, but conscious sedation adds time and risk to the imaging process. 

The final MR challenge came on the patient safety side. The protocol required a cumulative gadolinium contrast load of approximately 40 ccs. In many cases, physicians could not determine patients’ renal function prior to contrast injection, potentially