Rethinking the use of gallium in the era of SPECT CT

Objectives We reviewed our first 100 gallium SCT (GaSCT) and bone-gallium dual isotope SCT (DISCT) examinations. The objective is to see if these exams are useful in defining the extent of infection and discordance of bone and gallium uptake.

Methods Patients underwent these exams as part of routine clinical evaluation and were treated in part based on the interpretations. Confirmation based on surgery or follow up is incomplete. The results of surgery, follow up rstudies and clinical follow up were used to evaluate the efficacy of infection imaging.

Results GaSCT was used in vascular infections, foot ulcers, and soft tissue abscesses. Infection was confirmed at surgery in a case of aortic valve and graft infection and in several abscesses. In 10 cases, gallium was confined to the soft tissue of the plantar surface of the foot and the diagnosis of osteomyelitis was excluded on that basis. In the spine, 8 dual isotope studies were performed on patients with abnormal MRI exams suggesting diskitis or osteomyelitis. In 6 of the cases, bone and gallium uptake showed perfect concordance and the activity was confined to the endplates of the vertebral bodies. In 1 case a paraspinal abscess was found on SCT after a disk space aspirate was negative. In another case, SCT showed a focus of gallium in the vertebral body that did not accumulate the bone agent. Biopsy showed vertebral osteomyelitis. One false positive was found when gallium in the sternum was found to be due to postoperative inflammation.

Conclusions Gallium and bone-gallium dual isotope SPECT CT can localize gallium uptake making it an excellent agent for defining the location and extent of a variety of infections.