Diffusion-weighted MR imaging in pancreatic endocrine tumors correlated with histopathologic characteristics

Yi Wang, Zongming E. Chen, Vahid Yaghmai, Paul Nikolaidis, Robert J. McCarthy, Laura Merrick, Frank H. Miller

Research output: Contribution to journalArticlepeer-review

111 Scopus citations

Abstract

Purpose: To retrospectively assess apparent diffusion coefficients (ADCs) of different subtypes of pancreatic endocrine tumors based on the World Health Organization (WHO) classification system and analyze the potentially responsible histopathologic characteristics. Materials and Methods: Following Institutional Review Board (IRB) approval, 18 patients with surgical pathology-proven pancreatic endocrine tumors were evaluated. Tumors were subcategorized based on the WHO grading classification into well-differentiated tumors with benign and uncertain behavior and endocrine carcinomas with well and poor differentiation. ADCs were measured on diffusion-weighted (DW) images and compared using Student's t-test and one-way analysis of variance. The correlation between ADCs, tumor cellularity, Ki-67 labeling index (an index of cell growth), and extracellular fibrosis were analyzed. Results: A difference was demonstrated in mean ADCs between well-differentiated endocrine tumors (1.75 ± 0.53) and endocrine carcinomas (1.00 ± 0.19 × 10-3mm 2/sec) (P < 0.01). After excluding the three well-differentiated endocrine tumors with benign behavior and marked fibrosis, a significant inverse correlation between ADC values and cellularity of endocrine tumors was observed. An inverse correlation was seen between Ki-67 labeling index and ADC values (r = -0.70; P < 0.01). Conclusion: Tumor cellularity and/or extracellular fibrosis may account for various ADCs in pancreatic endocrine tumors. ADC correlates well with the Ki-67 labeling index and may help predict growth of endocrine tumors.

Original languageEnglish (US)
Pages (from-to)1071-1079
Number of pages9
JournalJournal of Magnetic Resonance Imaging
Volume33
Issue number5
DOIs
StatePublished - May 2011

Keywords

  • diffusion
  • pancreas
  • pancreas MR
  • pancreas neoplasms
  • pancreatic endocrine tumor

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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