title: Imaging characteristics of extrapulmonary tuberculosis lesions on dual time point imaging (DTPI) of FDG PET/CT.
abstract: BACKGROUND
  This study aimed to evaluate the diagnostic value of dual time point imaging (DTPI) of 18F-fluorodeoxyglucose (FDG) positron emission tomography/CT (PET/CT) for detecting the infective lesions in patients with extrapulmonary tuberculosis (EPTB).
  
  
  METHODS
  Eleven patients were consecutively recruited and evaluated. After the intravenous injection of 369 ± 153 MBq of FDG, all patients underwent FDG PET/CT imaging at two different time points: early scan at 57 ± 23 min and delayed scan at 136 ± 42 min. The maximum standardized uptake values (SUVmax) were recorded for both time points (early scan: SUVmax1 and delayed scan: SUVmax2).
  
  
  RESULTS
  In total, 30 lesions were detected. The SUVmax2 in 22 of the lesions in confirmed EPTB patients were significantly higher than the SUVmax1 (7.9 ± 3.2 vs. 6.8 ± 2.5; P = 0.001). The SUVmax for another eight non-EPTB lesions also showed a significant increasing pattern of change (6.2 ± 2.6 vs. 6.5 ± 2.8; P = 0.044). However, there was insignificant difference between the mean percentage difference of SUVmax (%ΔSUVmax) of EPTB and non-EPTB lesions (P = 0.06).
  
  
  CONCLUSIONS
  Our study demonstrates that early whole body PET/CT imaging may be sufficient for the detection of the EPTB lesions and DTPI of PET/CT may also not be a useful technique in differentiating between EPTB and non-EPTB lesions. However, our findings are based on a limited number of patients, and therefore, further investigations in larger series of patients are warranted.
authors.affiliation: Discipline of Medical Radiations, School of Medical Sciences, Bundoora West Campus, RMIT University, Victoria, Australia.
authors.forename: Hairil Rashmizal Abdul
authors.initials: HR
authors.lastname: Razak
authors.forename: Moshi
authors.initials: M
authors.lastname: Geso
authors.forename: Noraini
authors.initials: N
authors.lastname: Abdul Rahim
authors.forename: Abdul Jalil
authors.initials: AJ
authors.lastname: Nordin
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014376:Tuberculosis / Q000175:diagnosis*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18