title: Computed tomography and magnetic resonance imaging features of lipid-rich neuroendocrine tumors of the pancreas.
abstract: OBJECTIVE
  To clarify the computed tomography (CT) and magnetic resonance imaging (MRI) characteristics of lipid-rich pancreatic neuroendocrine tumors (PanNETs).
  
  
  METHODS
  Enhanced CT and MRI performed before pancreatectomy in 29 patients with 34 histologically-confirmed PanNETs was retrospectively reviewed. Tumor attenuation on CT and signal intensities on conventional (T1- and T2-weighted) and chemical shift MRI were qualitatively analyzed and compared alongside adipose differentiation-related protein (ADRP) immunostaining (ADRP-positive: lipid-rich; ADRP-negative: non-lipid-rich) results using Fisher's exact test or the Mann-Whitney U test. Signal intensity index on chemical shift MRI was quantitatively assessed.
  
  
  RESULTS
  There were 15 lipid-rich PanNETs (44.1%) in 12 patients (41.4%). Tumor attenuation during the early, portal venous, and delayed phases of enhanced CT (P = 0.888, 0.443, and 0.359, respectively) and signal intensities on conventional MRI (P = 0.698 and 0.798, respectively) were not significantly different between lipid-rich and non-lipid-rich PanNETs. Four of the 15 lipid-rich PanNETs exhibited high signal intensity on subtraction chemical shift MRI, and the association of high signal intensity on subtraction imaging with lipid-rich PanNETs was significant (4 of 15 lipid-rich PanNETs, 26.73%, vs 0 of 19 non-lipid-rich PanNETs, 0%, P = 0.029). Lipid-rich PanNETs showed a significantly higher signal intensity index than non-lipid-rich PanNETs (0.6% ± 14.1% vs -10.4% ± 14.4%, P = 0.004). Eight of 15 lipid-rich PanNETs, vs 0 of 19 non-lipid-rich PanNETs, had positive signal intensity index values in concordance with lipid contents.
  
  
  CONCLUSIONS
  CT contrast enhancement and conventional MR signal intensities are similar in lipid-rich and non-lipid-rich PanNETs. Chemical shift MRI can demonstrate cytoplasmic lipids in PanNETs.
authors.affiliation: Yoshihiko Fukukura, Toshikazu Shindo, Koji Takumi, Tomokazu Umanodan, Tomohide Yoneyama, Takashi Yoshiura, Department of Radiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima City 890-8544, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Fukukura
authors.affiliation: Yoshihiko Fukukura, Toshikazu Shindo, Koji Takumi, Tomokazu Umanodan, Tomohide Yoneyama, Takashi Yoshiura, Department of Radiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima City 890-8544, Japan.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Shindo
authors.affiliation: Yoshihiko Fukukura, Toshikazu Shindo, Koji Takumi, Tomokazu Umanodan, Tomohide Yoneyama, Takashi Yoshiura, Department of Radiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima City 890-8544, Japan.
authors.forename: Michiyo
authors.initials: M
authors.lastname: Higashi
authors.affiliation: Yoshihiko Fukukura, Toshikazu Shindo, Koji Takumi, Tomokazu Umanodan, Tomohide Yoneyama, Takashi Yoshiura, Department of Radiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima City 890-8544, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Takumi
authors.affiliation: Yoshihiko Fukukura, Toshikazu Shindo, Koji Takumi, Tomokazu Umanodan, Tomohide Yoneyama, Takashi Yoshiura, Department of Radiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima City 890-8544, Japan.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Umanodan
authors.affiliation: Yoshihiko Fukukura, Toshikazu Shindo, Koji Takumi, Tomokazu Umanodan, Tomohide Yoneyama, Takashi Yoshiura, Department of Radiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima City 890-8544, Japan.
authors.forename: Tomohide
authors.initials: T
authors.lastname: Yoneyama
authors.affiliation: Yoshihiko Fukukura, Toshikazu Shindo, Koji Takumi, Tomokazu Umanodan, Tomohide Yoneyama, Takashi Yoshiura, Department of Radiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima City 890-8544, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshiura
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D018278:Carcinoma, Neuroendocrine / Q000737:chemistry / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008055:Lipids / Q000032:analysis*; D008279:Magnetic Resonance Imaging; D008297:Male; D008565:Membrane Proteins / Q000032:analysis; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D000070780:Perilipin-2; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D008055:Lipids; D008565:Membrane Proteins; C000602982:PLIN2 protein, human; D000070780:Perilipin-2
keywords: Chemical shift magnetic resonance imaging; Computed tomography; Neoplasms; Neuroendocrine tumors; Pancreas