title: Combined ultrasmall superparamagnetic particles of iron oxide-enhanced and diffusion-weighted magnetic resonance imaging facilitates detection of metastases in normal-sized pelvic lymph nodes of patients with bladder and prostate cancer.
abstract: BACKGROUND
  Conventional cross-sectional imaging with computed tomography and magnetic resonance imaging (MRI) has limited accuracy for lymph node (LN) staging in bladder and prostate cancer patients.
  
  
  OBJECTIVE
  To prospectively assess the diagnostic accuracy of combined ultrasmall superparamagnetic particles of iron oxide (USPIO) MRI and diffusion-weighted (DW) MRI in staging of normal-sized pelvic LNs in bladder and/or prostate cancer patients.
  
  
  METHODS
  Examinations with 3-Tesla MRI 24-36 h after administration of USPIO using conventional MRI sequences combined with DW-MRI (USPIO-DW-MRI) were performed in 75 patients with clinically localised bladder and/or prostate cancer staged previously as N0 by conventional cross-sectional imaging. Combined USPIO-DW-MRI findings were analysed by three independent readers and correlated with histopathologic LN findings after extended pelvic LN dissection (PLND) and resection of primary tumours.
  
  
  METHODS
  Sensitivity and specificity for LN status of combined USPIO-DW-MRI versus histopathologic findings were evaluated per patient (primary end point) and per pelvic side (secondary end point). Time required for combined USPIO-DW-MRI reading was assessed.
  
  
  CONCLUSIONS
  At histopathologic analysis, 2993 LNs (median: 39 LNs; range: 17-68 LNs per patient) with 54 LN metastases (1.8%) were found in 20 of 75 (27%) patients. Per-patient sensitivity and specificity for detection of LN metastases by the three readers ranged from 65% to 75% and 93% to 96%, respectively; sensitivity and specificity per pelvic side ranged from 58% to 67% and 94% to 97%, respectively. Median reading time for the combined USPIO-DW-MRI images was 9 min (range: 3-26 min). A potential limitation is the absence of a node-to-node correlation of combined USPIO-DW-MRI and histopathologic analysis.
  
  
  CONCLUSIONS
  Combined USPIO-DW-MRI improves detection of metastases in normal-sized pelvic LNs of bladder and/or prostate cancer patients in a short reading time.
authors.affiliation: University Hospital of Bern, Department of Urology, Bern, Switzerland.
authors.forename: Frédéric D
authors.initials: FD
authors.lastname: Birkhäuser
authors.forename: Urs E
authors.initials: UE
authors.lastname: Studer
authors.forename: Johannes M
authors.initials: JM
authors.lastname: Froehlich
authors.forename: Maria
authors.initials: M
authors.lastname: Triantafyllou
authors.forename: Lauren J
authors.initials: LJ
authors.lastname: Bains
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Petralia
authors.forename: Peter
authors.initials: P
authors.lastname: Vermathen
authors.forename: Achim
authors.initials: A
authors.lastname: Fleischmann
authors.forename: Harriet C
authors.initials: HC
authors.lastname: Thoeny
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D003911:Dextrans; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D058185:Magnetite Nanoparticles; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D010388:Pelvis; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000473:pathology*; D001749:Urinary Bladder Neoplasms / Q000473:pathology*
chemical_list: D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; C097921:ferumoxtran-10
keywords: Bladder cancer; Diffusion-weighted MRI; Lymph node metastasis; Pelvic lymph node dissection; Prostate cancer; USPIO