If the development of a computed tomography/positron emission tomography (CT/PET) imaging system was a small step for diagnostic imaging, a system capable of performing simultaneously MRI and PET is a giant leap, according to Wilfried Loeffler, PhD, senior VP of clinical R&D for Siemens Medical Solutions (SMS; Berlin).

SMS recently reported a prototype for what it calls the “world’s first” MRI/PET system able to perform these functions simultaneously and terming it a turning point in diagnosis and therapy for those suffering from neurological diseases, stroke and cancer. Testing of the new prototype MR/PET will start before the end of 2007, SMS said.

“In comparison to [PET/CT] this is extremely complex,” Loeffler told Dignostics & Imaging Week. That’s because in PET/CT the two systems are simply sandwiched together, not done simultaneously, he explained.

“PET/CT technologically was a small step — this is a big step,” he said.

SMS said its MRI/PET prototype brings the “exceptional soft tissue contrast and high specificity of MRI together with PET’s excellent sensitivity in assessing physiological and metabolic state.”

The researchers expect MRI/PET to open new doors in understanding the pathologies and progression of Alzheimer’s, Parkinson’s, epilepsy and various psychic disorders. For example, PET can differentiate mild cognitive impairment from early-stage Alzheimer’s, but cannot determine reduced brain volume caused by atrophy. By combining PET with MRI, clinicians may be able to make a better determination of both cognitive impairment and atrophy.

In stroke patients, the technology holds the promise of enabling physicians to study, post-stroke, which brain tissues might be salvageable. In other rehab settings, such as for traumatic brain injury, MRIPET would improve care and workflow, the company said, because requiring just one scan and eliminate having to go to different locations for two scans.

He said that MRI/PET holds promise for emerging therapeutic research as well, for instance in the development of stem cell therapies. By allowing simultaneous measurement of anatomy, functionality and biochemistry of the body’s tissues and cells, it may enable researchers to correlate data in a way not previously possible.

— Amanda Pedersen