Whole body positron emission tomography detected occult infectious foci in a child with acute myeloid leukaemia

Update on pediatric leukemia and lymphoma imaging

Together, leukemia and lymphoma account for half of all childhood malignancies. Leukemia and lymphoma arise from similar cell lines and can have overlapping imaging features; however, the clinical presentation, imaging strategies, and treatment protocols can vary substantially based on the specific subtype. Although imaging does not play a central role in staging or monitoring disease in childhood leukemia, findings on imaging may be the first indication of the diagnosis. Advanced imaging, especially positron emission tomography/computed tomography, has moved to the forefront of staging and treatment response evaluation in Hodgkin's disease and non-Hodgkin's lymphoma. Imaging also plays a key role in evaluating the myriad of treatment complications that are commonly seen with chemotherapy and associated neutropenia. Future efforts will be largely focused on decreasing radiation exposure to these children, utilizing reduced or radiation-free modalities, such as positron emission tomography/magnetic resonance and diffusion-weighted whole-body imaging with background suppression, as well as refining surveillance imaging strategies. The purpose of this article is to briefly review the classification of pediatric leukemia and lymphoma, illustrate common imaging findings at presentation throughout the body, describe staging and therapeutic response evaluation, and show a spectrum of commonly encountered complications of treatment.

18F-fluorodeoxyglucose positron emission tomography contributes to the diagnosis and management of infections in patients with multiple myeloma: a study of 165 infectious episodes

PURPOSE

Correctly identifying infection in cancer patients can be challenging. Limited data suggest that positron emission tomography (PET) using fluorine-18 fluorodeoxyglucose (FDG) may be useful for diagnosing infection. To determine the role of FDG-PET in the diagnosis of infection in patients with multiple myeloma (MM).

PATIENTS AND METHODS

The medical records of 248 patients who had FDG-PET performed for MM staging or infection work-up revealing increased uptake at extramedullary sites and/or bones and joints that would be atypical for MM between October 2001 and May 2004 were reviewed to identify infections and evaluate FDG-PET contribution to patient outcome.

RESULTS

One hundred sixty-five infections were identified in 143 adults with MM. Infections involved the respiratory tract [99; pneumonia (93), sinusitis (six)], bone, joint and soft tissues [26; discitis (10), osteomyelitis (nine), septic arthritis (one), cellulitis (six)], vascular system [18; septic thrombophlebitis (nine), infection of implantable catheter (eight), septic emboli (one)], gastrointestinal tract [12; colitis (seven), abdominal abscess (three), and diverticulitis and esophagitis (one each)], and dentition [periodontal abscess (10)]. Infections were caused by bacteria, mycobacteria, fungi, and viruses. FDG-PET detected infection even in patients with severe neutropenia and lymphopenia (30 episodes). The FDG-PET findings identified infections not detectable by other methods (46 episodes), determined extent of infection (32 episodes), and led to modification of work-up and therapy (55 episodes). Twenty silent, but clinically relevant, infections were detected among patients undergoing staging FDG-PET.

CONCLUSION

In patients with MM, FDG-PET is a useful tool for diagnosing and managing infections even in the setting of severe immunosuppression.