title: Apparent diffusion coefficient characteristics of various adrenal tumors.
abstract: OBJECTIVE
  Using pathologically proven tumors and 3 methods of apparent diffusion coefficient (ADC) measurement, we examined the potential of diffusion-weighted imaging (DWI) to differentiate adrenal tumors.
  
  
  METHODS
  We evaluated adrenal tumors of 52 patients who underwent magnetic resonance (MR) examination including DWI and adrenal resection or biopsy between July 2006 and August 2011. Tumors included 25 cortical adenomas, 14 pheochromocytomas, 6 adrenal metastases, and seven others. We defined the tumor's "solid" region as an enhancing area on contrast-enhanced MR or computed tomography (CT) and measured the ADC of the tumor's "entire" and "solid" regions within a region of interest (ROI) placed on an ADC map ("entire" and "solid" ADCs). We obtained a "minimum" ADC by placing an ROI in an area showing the lowest ADC within the "solid" region. We also calculated the ratio of "non-solid" area to "entire" tumor and compared the average "entire," "solid," and "minimum" ADCs and the ratio of "non-solid" area to "entire" tumor between benign and malignant groups.
  
  
  RESULTS
  The average "entire" ADC was significantly higher for the benign (1.35 ± 0.38 × 10(-3) mm2/s) than malignant group (1.01 ± 0.17 × 10(-3) mm2/s), and the average "solid" and "minimum" ADC and the ratio of "non-solid" area to "entire" tumor did not differ significantly between the benign and malignant groups.
  
  
  CONCLUSIONS
  The higher "entire" ADC value of the benign group, which might be obtained incidentally, can be considered dependent on the condition of necrosis, hemorrhage, and degeneration. ADC measurement of a tumor's "solid" region was not useful for differentiating pathologically proven adrenal tumors.
authors.affiliation: Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Hida
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nishie
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Asayama
authors.forename: Kousei
authors.initials: K
authors.lastname: Ishigami
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ushijima
authors.forename: Yukihisa
authors.initials: Y
authors.lastname: Takayama
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Fujita
authors.forename: Dai
authors.initials: D
authors.lastname: Shimamoto
authors.forename: Akira
authors.initials: A
authors.lastname: Yokomizo
authors.forename: Katsunori
authors.initials: K
authors.lastname: Tatsugami
authors.forename: Junichi
authors.initials: J
authors.lastname: Inokuchi
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Kubo
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Honda
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000175:diagnosis*; D000311:Adrenal Glands / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D003287:Contrast Media