title: Can combined 18F-FDG-PET and dynamic contrast-enhanced MRI predict behavior of desmoid tumors in patients with familial adenomatous polyposis?
abstract: BACKGROUND
  Desmoid tumors associated with familial adenomatous polyposis show variable behavior; about 10% grow relentlessly, resulting in severe morbidity or mortality. Investigations that could identify the minority of desmoid tumors that behave aggressively would allow these tumors to be treated early and spare the majority of patients who have more benign disease from unnecessary intervention.
  
  
  OBJECTIVE
  The aim of this study was to investigate whether imaging the tumor metabolic-vascular phenotype by modern methods predicts growth.
  
  
  METHODS
  This is a prospective case series study.
  
  
  METHODS
  The study was conducted at a tertiary center specializing in familial adenomatous polyposis and desmoid disease.
  
  
  METHODS
  Nine patients with familial adenomatous polyposis (4 male, mean age 39 years) with desmoid tumor underwent 18F-FDG-PET and dynamic contrast-enhanced MRI. Standard MRI was repeated a year later to assess tumor growth.
  
  
  METHODS
  The primary outcome measured was the correlation between 18F-FDG-PET and dynamic contrast-enhanced MRI parameters and subsequent desmoid growth.
  
  
  RESULTS
  Failed intravenous access precluded dynamic contrast-enhanced MRI in 1 female patient. Thirteen desmoid tumors (4 intra-abdominal, 2 extra-abdominal, 7 abdominal wall; mean area, 68 cm) were analyzed in the remaining 8 patients. Two patients died before follow-up MRI. Five tumors decreased in size, 3 increased in size, and 3 remained stable after a year. Significant correlation (Spearman rank correlation, significance at 5%) existed between maximum standardized uptake value and k(ep) (r = -0.56, p = 0.04), but not with other vascular parameters (K(trans) (r = -0.47, p = 0.09); v(e) (r = -0.11, p = 0.72); integrated area under the gadolinium-time curve at 60 seconds (r = -0.47, p = 0.10)). There was no significant difference in the maximum standardized uptake value or dynamic contrast-enhanced MRI parameters (K(trans), v(e), k(ep), integrated area under the gadolinium-time curve at 60 seconds) between the tumors that grew or decreased in size or between the tumor sites. However, vascular metabolic ratio (maximum standardized uptake value/K(trans)) was significantly different for tumor site (p = 0.001) and size (p = 0.001, 1-way ANOVA).
  
  
  CONCLUSIONS
  This investigation is limited because of its exploratory nature and small patient numbers.
  
  
  CONCLUSIONS
  Although not predictive for tumor behavior, some correlations existed between dynamic contrast-enhanced MRI and 18F-FDG-PET parameters. Vascular metabolic ratio may provide further information on tumor behavior; however, this needs to be evaluated with further larger studies.
authors.affiliation: 1The Polyposis Registry, St Mark's Hospital, Harrow, London, United Kingdom 2Paul Strickland Scanner Centre, Mount Vernon Hospital, Northwood, London, United Kingdom 3Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom.
authors.forename: S
authors.initials: S
authors.lastname: Bhandari
authors.forename: N J
authors.initials: NJ
authors.lastname: Taylor
authors.forename: A
authors.initials: A
authors.lastname: Sinha
authors.forename: L
authors.initials: L
authors.lastname: Sonoda
authors.forename: B
authors.initials: B
authors.lastname: Sanghera
authors.forename: W L
authors.initials: WL
authors.lastname: Wong
authors.forename: V
authors.initials: V
authors.lastname: Goh
authors.forename: S K
authors.initials: SK
authors.lastname: Clark
mesh_terms: D011125:Adenomatous Polyposis Coli / Q000000981:diagnostic imaging / Q000473:pathology*; D000328:Adult; D000704:Analysis of Variance; D019540:Area Under Curve; D003287:Contrast Media; D005260:Female; D018221:Fibromatosis, Abdominal / Q000000981:diagnostic imaging / Q000473:pathology*; D019788:Fluorodeoxyglucose F18; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010641:Phenotype; D049268:Positron-Emission Tomography / Q000379:methods*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D019275:Radiopharmaceuticals
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D019786:Gadolinium DTPA