title: Contrast enhanced computed tomography characterization of fluorodeoxygluocose-avid regional and non-regional lymph nodes in patients with suspicion of metastatic bladder cancer.
abstract: OBJECTIVE
  The objective of this study is to assess if size alone can predict the presence of metastatic disease within lymph nodes seen on contrast enhanced-computed tomography (CE-CT) in patients with suspicion of metastatic bladder cancer and also to evaluate the nodal distribution and morphological characteristics of fluorodeoxygluocose (FDG) avid lymph nodes on CE-CT.
  
  
  METHODS
  A retrospective analysis from 2002 to 2009 was performed on patients with suspicion of recurrent disease undergoing restaging FDG-positron emission tomography (PET)/CT. Standardized uptake value (SUVmax) adjusted for lean body mass was recorded in abnormal lymph nodes in the abdominopelvic region. Distribution, size, shape, presence of necrosis and clustering of the FDG-avid lymph nodes was assessed on CE-CT obtained within 4 weeks of the PET/CT. The abnormal nodes were then compared with non-FDG avid lymph nodes on the contralateral side serving as control.
  
  
  RESULTS
  A total of 103 lymph nodes were found to be FDG-avid in 14 patients on 17 PET/CT examinations. Overall, mean SULmax was 4.7 (range: 1.6-10.7), which is significantly higher than background of 1.5 (P < 0.05). Regional pelvic lymph nodes were FDG-avid in 93% of patients and metastatic extra-pelvic in 100% of patients. The overall average size of the FDG avid lymph nodes on CE-CT was 11 mm with a third of these measuring 3-8 mm. The average size of FDG-avid lymph nodes was 11 mm in the paraaortic region 13 mm in the common iliac 9 mm in the internal iliac and 13 mm in the external iliac regions. Nearly 88.4% of lymph nodes were round in shape, clustering was present in 68% and necrosis in 7% and average size of lymph nodes that served as controls was 6 mm with reniform morphology in 92% and absence of clustering and necrosis.
  
  
  CONCLUSIONS
  Overlap in size exists between FDG-avid pathological and non-pathological lymph nodes seen on CE-CT in patients with metastatic bladder cancer. Other characteristic such as abnormal morphology and clustering are useful adjuncts in the evaluation of nodal metastatic disease.
authors.affiliation: Russell H. Morgan Department of Radiology and Radiological Health Sciences, Division of Diagnostic Imaging, Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA ; Division of Nuclear Medicine, Al Ain, United Arab Emirates.
authors.forename: Muhammad A
authors.initials: MA
authors.lastname: Chaudhry
authors.affiliation: Russell H. Morgan Department of Radiology and Radiological Health Sciences, Division of Diagnostic Imaging, Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA ; Division of Nuclear Medicine, Al Ain, United Arab Emirates.
authors.forename: Richard
authors.initials: R
authors.lastname: Wahl
authors.affiliation: Tawam Molecular Imaging Centre, Al Ain, United Arab Emirates.
authors.forename: Lujaien Al-Rubaiey
authors.initials: LA
authors.lastname: Kadhim
authors.affiliation: Russell H. Morgan Department of Radiology and Radiological Health Sciences, Division of Diagnostic Imaging, Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA.
authors.forename: Atif
authors.initials: A
authors.lastname: Zaheer
keywords: Bladder cancer; contrast-enhanced imaging; fluorodeoxygluocose positron emission tomography/computed tomography