title: Perfusion characterization of liver metastases from endocrine tumors: Computed tomography perfusion.
abstract: OBJECTIVE
  To assess prospectively parameters of computed tomography perfusion (CT p) for evaluation of vascularity of liver metastases from neuroendocrine tumors.
  
  
  METHODS
  This study was approved by the hospital's institutional review board. All 18 patients provided informed consent. There were 30 liver metastases from neuroendocrine tumors. Patients were divided into three groups depending on the appearance of the liver metastases at the arterial phase of morphological CT (hyperdense, hypodense and necrotic). Sequential acquisition of the liver was performed before and for 2 min after intravenous injection of 0.5 mg/kg contrast medium, at 4 mL/s. Data were analyzed using deconvolution analysis to calculate blood flow (BF), blood volume (BV), mean transit time (MTT), hepatic arterial perfusion index (HAPI) and a bi-compartmental analysis was performed to obtain vascular permeability-surface area product (PS). Post-treatment analysis was performed by a radiologist and regions of interest were plotted on the metastases, normal liver, aorta and portal vein.
  
  
  RESULTS
  At the arterial phase of the morphological CT scan, the aspects of liver metastases were hyperdense (n = 21), hypodense (n = 7), and necrotic (n = 2). In cases of necrotic metastases, none of the CT p parameters were changed. Compared to normal liver, a significant difference in all CT p parameters was found in cases of hyperdense metastases, and only for HAPI and MTT in cases of hypodense metastases. No significant difference was found for MTT and HAPI between hypo- and hyperdense metastases. A significant decrease of PS, BV and BF was demonstrated in cases of patients with hypodense lesions PS (23 ± 11.6 mL/100 g per minute) compared to patients with hyperdense lesions; PS (13.5 ± 10.4 mL/100 g per minute), BF (93.7 ± 75.4 vs 196.0 ± 115.6 mL/100 g per minute) and BV (9.7 ± 5.9 vs 24.5 ± 10.9 mL/100 g).
  
  
  CONCLUSIONS
  CT p provides additional information compared to the morphological appearance of liver metastases.
authors.affiliation: Aurélie Guyennon, Marius Mihaila, John Palma, Frank Pilleul, Department of Gastrointestinal Radiology, University Hospital Edouard Herriot, 5 Place d'Arsonval 69437 Lyon, France.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Guyennon
authors.forename: Marius
authors.initials: M
authors.lastname: Mihaila
authors.forename: John
authors.initials: J
authors.lastname: Palma
authors.forename: Catherine
authors.initials: C
authors.lastname: Lombard-Bohas
authors.forename: Jean-Alain
authors.initials: JA
authors.lastname: Chayvialle
authors.forename: Frank
authors.initials: F
authors.lastname: Pilleul