SPECT/CT fusion images reveal liver lesions not seen on CT scans alone

CT scans are matched in location to SPECT images obtained separately using Siemens TruePoint Symbia. CT (top image) shows a metastatic lesion in the right lobe of the liver in a 70-year-old man. The lesion is barely visible in the following CT (second from top) but is clearly evident on SPECT image (third from top).

A smaller lesion, not seen with CT, appears in the second SPECT slice (bottom image).

SPECT scans were obtained using 6 mCi indium-111 Octreoscan with a 48-hour uptake. CTs were obtained using a six-slice/rotation configuration at 2-mm collimation and 5-mm slice thickness.

Side-by-side comparisons can assist in the identification of abnormalities, although fusing the images may improve anatomic localization. TruePoint Symbia supports the presentation of images in either fashion. The system is configured with the company's e.cam dual-detector gamma camera with either a dual- or six-slice CT.

GE Healthcare already offers the Infinia/Hawkeye SPECT/CT system, which incorporates a nondiagnostic CT scanner that provides general localization and attenuation correction.

Full production of TruePoint Symbia is slated for the first half of 2005. Commercial shipments of another SPECT/CT family, Philips' Precedence, is scheduled to begin in April. Precedence SPECT/CT can be configured for six, 10, and 16 slices. (Provided by Dr. Morand Piert, University of Michigan, Ann Arbor)