title: Evaluation of neuroendocrine liver metastases: a comparison of dynamic contrast-enhanced magnetic resonance imaging and positron emission tomography/computed tomography.
abstract: OBJECTIVE
  The objective of this study was to evaluate the correlation between dynamic gadoxetic acid-enhanced magnetic resonance imaging parameters and specific uptake values (SUVs) derived from ¹⁸fluorodeoxyglucose (¹⁸F-FDG) and ⁶⁸Ga-DOTA-Tyr(3)-octreotate (⁶⁸Ga-DOTATATE) positron emission tomography/computed tomography (PET/CT) in patients with liver metastases of neuroendocrine neoplasms.
  
  
  METHODS
  A total of 42 patients with hepatic metastases of neuroendocrine neoplasms were prospectively enrolled and underwent both dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and PET/CT, using either ¹⁸F-FDG or ⁶⁸Ga-DOTATATE as tracer. The DCE-MRI was performed at 3 T with gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid acquiring 48 slices every 2.2 seconds for 5 minutes. Three regions of interest (ROIs) representing the liver background and up to 3 ROIs representing metastatic liver tissue were coregistered in the PET/CT and in the DCE-MRI data sets. For each patient, a dedicated dual-inlet, 2-compartment uptake model was fitted to the enhancement curves of DCE-MRI ROIs and perfusion parameters were calculated. Lesion-to-background ratios of SUVs were correlated with corresponding lesion-to-background ratios of the perfusion parameters arterial plasma flow, venous plasma flow, total plasma flow, extracellular mean transit time, extracellular volume, arterial flow fraction, intracellular uptake rate, and hepatic uptake fraction using the Spearman coefficient.
  
  
  RESULTS
  Whereas the lesion-to-background ratios of arterial plasma flow and arterial flow fraction of liver metastases correlated negatively with the lesion-to-background ratios of SUV(mean) derived from ⁶⁸Ga-DOTATATE PET/CT (r = -0.54, P < 0.001; r = -0.39, P < 0.001, respectively), they correlated positively with the lesion-to-background ratios of SUV(mean) derived from ¹⁸F-FDG-PET/CT (r = 0.51, P < 0.05; r = 0.68, P < 0.01, respectively). The lesion-to-background ratios of the DCE-MRI parameters extracellular mean transit time and extracellular volume correlated very weakly with the lesion-to-background ratios of SUV(mean) from ⁶⁸Ga-DOTATATE PET/CT, whereas venous plasma flow, total plasma flow, hepatic uptake fraction, and intracellular uptake rate showed no correlation between DCE-MRI and PET/CT.
  
  
  CONCLUSIONS
  Both ⁶⁸Ga-DOTATATE and ¹⁸fluorodeoxyglucose PET/CT partially correlate with MRI perfusion parameters from the dual-inlet, 2-compartment uptake model. The results indicate that the paired imaging methods deliver complementary functional information.
authors.affiliation: From the *Department of Clinical Radiology, University Hospitals-Grosshadern, Ludwig Maximilians University, Munich, Germany; †Division of Medical Physics, University of Leeds, Leeds, United Kingdom; ‡Department of Nuclear Medicine, University Hospitals-Grosshadern, Ludwig Maximilians University, Munich, Germany; §Department of Clinical Radiology, University of Basel, Basel, Switzerland; and ¶Department of Internal Medicine II, Campus Grosshadern, Interdisciplinary Center of Neuroendocrine Tumors of the GastroEnteroPancreatic System, University Hospitals-Grosshadern, Ludwig Maximilians University, Munich, Germany.
authors.forename: Marco
authors.initials: M
authors.lastname: Armbruster
authors.forename: Steven
authors.initials: S
authors.lastname: Sourbron
authors.forename: Alexander
authors.initials: A
authors.lastname: Haug
authors.forename: Christoph J
authors.initials: CJ
authors.lastname: Zech
authors.forename: Michael
authors.initials: M
authors.lastname: Ingrisch
authors.forename: Christoph J
authors.initials: CJ
authors.lastname: Auernhammer
authors.forename: Konstantin
authors.initials: K
authors.lastname: Nikolaou
authors.forename: Philipp M
authors.initials: PM
authors.lastname: Paprottka
authors.forename: Carsten
authors.initials: C
authors.lastname: Rist
authors.forename: Maximilian F
authors.initials: MF
authors.lastname: Reiser
authors.forename: Wieland H
authors.initials: WH
authors.lastname: Sommer
mesh_terms: D003287:Contrast Media; D056831:Coordination Complexes; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000556:secondary*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D018358:Neuroendocrine Tumors / Q000175:diagnosis* / Q000556:secondary*; D015282:Octreotide / Q000031:analogs & derivatives; D009942:Organometallic Compounds; D049268:Positron-Emission Tomography / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: C572954:111indium-DOTA, Tyr(3)-octreotate; D003287:Contrast Media; D056831:Coordination Complexes; D009942:Organometallic Compounds; D019788:Fluorodeoxyglucose F18; C513399:gallium Ga 68 dotatate; D015282:Octreotide