18FDG PET versus high-dose 67Ga scintigraphy for restaging and treatment follow-up of lymphoma patients.

To date, only one published study has directly compared 67Ga scintigraphy (low dose, planar) with planar dual-head gamma camera 18F-fluorodeoxyglucose (18FDG) imaging for the purpose of treatment follow-up monitoring in lymphoma patients, and no data on restaging are available. The present study reports the direct comparison of high-dose (297-370 MBq) 67Ga planar and single photon emission computed tomography (SPECT) imaging and conventional 18FDG positron emission tomography (PET) for restaging and treatment follow-up of lymphoma patients versus a gold standard consisting of morphological imaging, including plain radiography and computed tomography (CT) scanning, bone marrow examination and long-term follow-up (<12 months). Sixteen patients, 10 with non-Hodgkin's lymphoma and six with Hodgkin's disease, were included (10 men, six women; median age, 43 years; range, 16-64 years). The median follow-up time was 27 months (range, 12-34 months). In two patients, 67Ga and 18FDG PET (370 MBq) were performed twice, resulting in 18 cross-sectional episodes. In 11 episodes, the results obtained by both imaging modalities were in agreement with regard to the presence or absence of disease when compared with the gold standard. However, the abnormalities found on 18FDG PET were always more extensive. In two episodes, 67Ga imaging normalized after treatment, whereas PET showed significant regression followed by subsequent normalization. In four additional episodes, 67Ga images were negative, whereas 18FDG PET visualized non-tumour-related pathology, such as lung infection, rib fracture or dense thymic tissue. In one gold standard-negative patient, the underlying cause of sternal FDG uptake remained undetermined. The data presented, although limited in number, suggest that 18FDG PET performs better than Ga imaging in monitoring lymphoma disease status. However, a correlation with clinical history and a knowledge of the characteristics of benign lesions are mandatory. Further studies are recommended.

In-111 WBC imaging of osteomyelitis in patients with underlying bone scan abnormalities.

One hundred seven combined In-111 WBC/Tc-99m MDP scans performed on 87 patients with a high clinical suspicion of osteomyelitis were retrospectively reviewed. An 86% sensitivity and a 94% specificity for detecting osteomyelitis were found. In addition, patients were grouped into one of five clinical settings for more detailed analysis: diabetic osteoarthropathy, previous arthroplasty, fracture, overlying skin ulcer, and other etiology. Forty-seven studies were performed while patients received antibiotic therapy without loss of sensitivity for detecting osteomyelitis. Results obtained with scintigraphy compared favorably to other imaging and laboratory studies used to detect osteomyelitis. In conclusion, the combined In-111 WBC/Tc-99m MDP scan is a very sensitive and specific method to detect osteomyelitis in patients with concurrent diabetic osteoarthropathy, fracture, postoperative healing, and overlying skin ulcer. Antibiotic treatment does not appear to adversely affect the sensitivity of these scans.

Pedal radiocolloid lymphoscintigraphy in demonstration of a post-surgical lymphatic leak.

Radiocolloid lymphoscintigraphy is a very effective diagnostic procedure for dynamic evaluation of lymphatic flow. In this case report, the use of radiocolloid lymphoscintigraphy in detection of a post-surgical lymphatic leak is presented. Dynamic pedal lymphoscintigraphy with Tc 99m-antimony trisulfide colloid clearly demonstrated the site of the leak.