title: Measurement of Tissue interstitial volume in healthy patients and those with amyloidosis with equilibrium contrast-enhanced MR imaging.
abstract: OBJECTIVE
  To investigate equilibrium contrast material-enhanced magnetic resonance (MR) imaging measurement of extracellular volume (ECV) fraction within healthy abdominal tissues and to test the hypotheses that tissue ECV in systemic amyloid light-chain (AL) amyloidosis is greater than in healthy patients and show that this increase correlates with organ amyloid burden.
  
  
  METHODS
  A local ethics committee approved the study and all patients gave written informed consent. Forty healthy volunteers (18 men, 22 women; median age, 43 years; age range, 24-88 years) and 67 patients with AL amyloidosis (43 men, 24 women; median age, 65 years; age range, 38-81 years) underwent equilibrium MR imaging of the upper abdomen. ECV was measured in the liver, spleen, and paravertebral muscle. Patients with amyloidosis also underwent serum amyloid P (SAP) component scintigraphy so that specific organ involvement by amyloid could be scored. Variation in ECV between tissues was assessed by using a Friedman Test. Tissue ECV in healthy and amyloidosis groups were compared by using a Mann-Whitney U test. Spearman correlation was used to test for an association between the organ SAP score and ECV.
  
  
  RESULTS
  ECV measured at equilibrium MR imaging varied significantly between organs in healthy volunteers (χ(2) = 31.0; P < .001). ECV was highest in the spleen (0.34), followed by liver (0.29) and muscle (0.09). ECVs measured within the spleen (0.39; P< .001), liver (0.31; P = .005), and muscle (0.16; P< .001) were significantly higher in patients with amyloidosis than in healthy control subjects. ECV measured in the liver and spleen showed increasing organ amyloid burden assessed at SAP scintigraphy (liver, rs = 0.54; spleen, rs = 0.57).
  
  
  CONCLUSIONS
  Equilibrium MR imaging can be used to define ECV within healthy tissues. ECV is increased in amyloidosis compared with healthy tissues, and this increase correlates with rising tissue amyloid burden.
authors.affiliation: Centre for Medical Imaging, Institute of Cardiovascular Science, University College London, London, England.
authors.forename: Steve
authors.initials: S
authors.lastname: Bandula
authors.forename: Sanjay M
authors.initials: SM
authors.lastname: Banypersad
authors.forename: Daniel
authors.initials: D
authors.lastname: Sado
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Flett
authors.forename: Shonit
authors.initials: S
authors.lastname: Punwani
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Taylor
authors.forename: Philip N
authors.initials: PN
authors.lastname: Hawkins
authors.forename: James C
authors.initials: JC
authors.lastname: Moon
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000686:Amyloidosis / Q000473:pathology*; D003287:Contrast Media; D045604:Extracellular Fluid / Q000166:cytology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008099:Liver / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008536:Meglumine; D008875:Middle Aged; D009929:Organ Size; D009942:Organometallic Compounds; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013154:Spleen / Q000473:pathology*; D055815:Young Adult
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D008536:Meglumine; C072417:gadoterate meglumine