The added value of SPECT/CT in complicated osteomyelitis

[摘要] ENGLISH ABSTRACT: Background: The detection of bone infection can be very difficult especially in bone with alteredstructure due to prior trauma or surgical procedures. Complicated osteomyelitis (COM) is becoming apublic health problem especially with the difficult choice between, high cost surgery and prolongedcourses of intravenous or oral antibiotic therapy, as well as the social and psychological effect of longtermdisease and disability of the patient. The correct localisation of especially bone infection is still achallenge for the clinician. The single photon emission computed tomography/low dose computedtomography (SPECT/CT), by fusing the functional information with the anatomical parts, is a wellestablishedtool used in many nuclear medicine studies. This improves the overall quality of the studywith more clear answers. The aim of the study was to determine the added value of SPECT/CT in themanagement of complicated osteomyelitis (COM) in patients with endo-prosthesis, post traumaticosteomyelitis with and without metal implants and diabetic foot.Methods: This was a prospective study, between February 2010 and February 2012. Patients withsuspected COM who fulfilled the selection and inclusion criteria were included. All had abnormal threephase bone scan followed by infection imaging with 99mTc labelled white blood cells and 99mTc -colloid ifthe99mTc labelled white blood cell study was abnormal. 67Ga citrate was used in vertebral involvement.Planar and SPECT/CT images were reviewed for presence of abnormal uptake and for its localization inbone and soft tissue. Scan results were defined as positive or negative. Both planar and SPECT/CTimages were compared regarding diagnosis and precise localization of infection. The final diagnosis wasobtained from surgical specimen or microbiological culture as well as clinical follow-up of all patients.Results: There were 72 patients, 29 male and 43 female with mean age of 57 yrs [range 27-88].Therewere 24 patients with prosthesis, 16 with hip prosthesis (PH=16), and 8 with knee prosthesis (PK=8).There were 44 patients with post traumatic osteomyelitis, 26 with metal implants (TOM=26) and 18without metal implants (TOWM= 18). Four patients had diabetic foot (DF= 4). Infection was diagnosedin 19/72 patients on planar images and in 21/72 on SPECT/CT. Infection was diagnosed in 4 patientswith prosthesis, 16 patients with post traumatic injury and one diabetic foot patient. The four patientswith prosthesis, SPECT /CT added diagnostic value by excluding osteomyelitis in 3 patients and bydefining the exact extent and localizing soft tissue and bone infection (STI/OM) in one patient. In 16patients with post traumatic OM on planar images, SPECT /CT added diagnostic value, by excluding OM in 4 patients and confirming only STI, better localisation of the uptake in boneand soft tissue in 5 patients, of them 2 patient was negative on planar, and in 7 patients, confirmed anddefined the exact extent ofboth OM and STI. One diabetic foot was positive for STI on the planar, the SPECT/CT added diagnosticvalue by defining the extent of the infection.In summary the added value of SPECT/CT was:a. Overall infection:1. Exclusion of osteomyelitis by confirming only soft tissue involvement: 7 patients (10%)2. Better localization in bone and soft tissue: 6 patients (8%)3. Better delineation of extent of infection: 9 patients (12%)4. None: 50 patients (70%)b. In positive cases only:1. Exclusion of osteomyelitis by confirming only soft tissue involvement: 7 patients (33%)2. Better localization in bone and soft tissue: 5 patients (24%)3. Better delineation of extent of infection: 9 patients (43%)4. None: 0 patientsThe overall sensitivity, specificity, positive predictive value, negative predictive value and accuracy forinfection, on planar was 90%, 100%, 100%, 97%, 97%, respectively and for SPECT/CT 100%, 100%,100%, 100%, 100%. For OM on planar, the sensitivity, specificity , positive predictive value, negativepredictive value and accuracy was 100%, 89%, 53%, 100%, 90%, respectively and for SPECT/CT 100%,100%, 100%, 100%, 100%.Conclusion:In complicated osteomyelitis, SPECT/CT is useful in localizing, defining the exact extent of infectionwhere the planar images are abnormal, with no added value if the planar images are negative. Werecommend in clinical practice the routine use of hybrid SPECT/CT imaging in complicated osteomyelitiswhen planar images are abnormal.

[发布机构] Stellenbosch University