Automated Method Fuses MRI and SPECT Prostate Images

ST. LOUIS—An automated technique for coregistering MRI or CT images with SPECT (single photo emission computed tomography) images has the potential to improve the accuracy of prostate cancer staging, according to research presented at the Society of Nuclear Medicine 47^th Annual Meeting.

Sophisticated Software

Zhenghong Lee, PhD, D. Bruce Sodee, MD, and their colleagues at University Hospitals of Cleveland/Case Western Reserve University used sophisticated new software to automatically coregister results with SPECT imaging of ProstaScint (a monoclonal antibody labeled with indium-111) and MRI in prostate cancer patients.

The resulting image shows the site of SPECT metabolic activity superimposed on the same MRI-defined anatomic slice. The researchers have also used the technique to coregister SPECT and CT prostate cancer images.

The software maximizes Mutual Information, or relative entropy between the two volumes, to calculate the optimal alignment of the SPECT/ProstaScint and MRI images.

Virtual 3D Presentation

Data from this “fused” image is presented in virtually three dimensions, or virtual 3D. “The result,” Dr. Sodee said, “is a significantly clearer image of the tumor’s size and exact location.”

The 3D virtual software will also have applications in coregistering PET (positron emission tomography) images of metabolic cancer activity with anatomic CT or MRI correlation, Dr. Lee said.