18F-FDG PET/CT characteristics of extramedullary relapse of acute leukemia / 中国医学影像技术

ABSTRACT

Objective To explore 18F-FDG PET/CT characteristics of extramedullary relapse in patients with acute leukemia (AL).Methods Thirty AL patients with extramedullary relapse were retrospectively evaluated.The infiltrated organs or tissues and the maximum standardized uptake value (SUVmax) were recorded and compared between patients with acute lymphoblastic leukemia (ALL) or acute myeloid leukemia (AML).FDG uptake pattern of bone marrow was also recorded.Results Forty-five extramedullary lesions were found in 16 ALL patients,while 29 were found in 14 AML patients.The average SUVmax was 7.38±4.46 in ALL patients and 4.87±2.66 in AML patients (t=3.022,P=0.003).Among ALL patients,lymph node and soft tissue involvement were detected each in 10,with SUVmax of 6.38 ± 3.55 and 10.12± 5.48,respectively.Among AML patients,lymph node and soft tissue involvement were detected in 6,with SUVmax of 4.82 ±1.43 and 6.60±4.58,respectively (P＞0.05).Multiple focal bone marrow uptakes of FDG were found in 5 of 5 intramedullary recurrence ALL patients and 2 of 5 intramedullary recurrence AML patients.The other 3 intramedullary recurrence AML patients showed diffuse bone marrow uptake.Conclusion There are certain imaging characteristics of 18 F-FDG PET/CT in extramedullary relapse of AL.The common relapse sites are lymph node and soft tissues in both ALL and AML.FDG uptakes of extramedullary relapse lesions in ALL are significantly higher than those of AML.Multiple focal bone marrow uptake of FDG is valuable in predicting intramedullary recurrence.