title: Fluid-fluid level in hepatic metastases: a characteristic sign of metastases of neuroendocrine origin.
abstract: OBJECTIVE
  The aim of this study is to determine MRI characteristics which indicate liver metastases of neuroendocrine tumors (NET) rather than metastases of other origin (non-NET).
  
  
  METHODS
  Sixty-nine patients with histopathologically proven liver metastases from NET and 69 patients with known liver metastases of other origin underwent MRI of the liver using a 1.5 T MR-scanner. Two board certified radiologists assessed presence of fluid-fluid-levels, number and distribution pattern, signal intensity (SI) characteristics, lesion homogeneity, presence of central necrosis and intratumoral hemorrhage in T2w and T1w non-contrast imaging. A multivariate logistic regression analysis was performed to determine the independent association of image findings and occurrence of NET.
  
  
  RESULTS
  Fluid-fluid-levels were identified in 19/69 of patients with NET-metastases, and in none of the patients in the control group (p<0.0001). Hyperintense SI in T1w imaging, markedly hyperintense SI in T2w imaging, a disseminated distribution pattern and intratumoral hemorrhage were indicative of NET metastases (p<0.05). After statistical adjustment for all significant MRI findings, fluid-fluid-levels (OR: 17.6, 95% CI: 1.9-166.5), strongly hyperintense SI in T2w (OR: 4.7, 95% CI: 1.8-12.7) and a disseminated distribution pattern (OR: 2.9, 95% CI: 1.1-7.4) were independent predictors for NET metastases.
  
  
  CONCLUSIONS
  The presence of fluid-fluid-levels is highly indicative of NET liver metastases and can be used as an independent predictor to distinguish them from metastases of other origin.
authors: Department of Clinical Radiology, University Hospitals-Grosshadern, Ludwig-Maximilians University, Munich, Germany. wieland.sommer@med.uni-muenchen.de
authors: Wieland H
authors: WH
authors: Sommer
authors: Christoph J
authors: CJ
authors: Zech
authors: Fabian
authors: F
authors: Bamberg
authors: Christoph J
authors: CJ
authors: Auernhammer
authors: Andreas
authors: A
authors: Helck
authors: Philipp M
authors: PM
authors: Paprottka
authors: Mike
authors: M
authors: Notohamiprodjo
authors: Maximilian F
authors: MF
authors: Reiser
authors: Karin A
authors: KA
authors: Herrmann
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D055316:Cystatin C; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology* / Q000556:secondary*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000473:pathology* / Q000556:secondary*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D055316:Cystatin C