title: Diuretic 18F-FDG PET/CT imaging for detection and locoregional staging of urinary bladder cancer: prospective evaluation of a novel technique.
abstract: OBJECTIVE
  Positron emission tomography/computed tomography (PET/CT) with (18)F-fluorodeoxyglucose (FDG) has been used with limited success in the past in primary diagnosis and locoregional staging of urinary bladder cancer, mainly because of the pharmacokinetics of renal excretion of (18)F-FDG. In the present prospective study, we have evaluated the potential application of diuretic (18)F-FDG PET/CT in improving detection and locoregional staging of urinary bladder tumours.
  
  
  METHODS
  Twenty-five patients suspected of having primary carcinoma of the urinary bladder were evaluated prospectively for diagnosis and staging. All of these 25 patients underwent conventional contrast-enhanced computed tomography (CECT) of the abdomen/pelvis and whole-body diuretic (18)F-FDG PET/CT. In addition, pelvic PET/CT images were obtained using the special technique of forced diuresis using intravenous furosemide (20-40 mg). Of the 25 patients, 10 underwent radical cystectomy and 15 underwent transurethral resection of the bladder tumour (TURBT). Results of CECT and diuretic (18)F-FDG PET/CT were compared considering histopathology as a reference standard.
  
  
  RESULTS
  Of the 25 patients, CECT detected a primary tumour in 23 (sensitivity 92 %), while (18)F-FDG PET/CT was positive in 24 patients (sensitivity 96 %). Mean size and maximum standardized uptake value of the bladder tumours were 3.33 cm (range 1.6-6.2) and 5.3 (range 1.3-11.7), respectively. Of the 25 patients, only 10 patients underwent radical cystectomy based on disease status on TURBT. Among those ten patients, nine had locoregional metastases. Among the nine patients who had positive lymph nodes for metastasis on histopathology, CECT and PET/CT scan had a sensitivity of 44 and 78 %, respectively. (18)F-FDG PET/CT was found to be superior to CECT in the detection of the primary tumour and locoregional staging (p < 0.05).
  
  
  CONCLUSIONS
  Diuretic (18)F-FDG PET/CT is highly sensitive and specific and plays an important role in improving detection of the primary tumour and locoregional staging of urinary bladder tumours. Diuretic (18)F-FDG PET/CT demonstrated a higher diagnostic value when compared with CECT in these patients.
authors.affiliation: Department of Urology, All India Institute of Medical Sciences, New Delhi, India. brusabhanu@gmail.com
authors.forename: Brusabhanu
authors.initials: B
authors.lastname: Nayak
authors.forename: Prem Nath
authors.initials: PN
authors.lastname: Dogra
authors.forename: Niraj
authors.initials: N
authors.lastname: Naswa
authors.forename: Rakesh
authors.initials: R
authors.lastname: Kumar
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004231:Diuresis; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed; D001749:Urinary Bladder Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000503:physiopathology; D055815:Young Adult
chemical_list: D019788:Fluorodeoxyglucose F18