title: Perfusion CT in colorectal cancer: comparison of perfusion parameters with tumor grade and microvessel density.
abstract: OBJECTIVE
  The purpose of this study was to prospectively compare pre-operative computed tomography (CT) perfusion parameters with tumor grade from colorectal adenocarcinoma (CRC) and to correlate pre-operative CT perfusion parameters with microvessel density (MVD) to evaluate angiogenesis in CRC.
  
  
  METHODS
  Pre-operative perfusion CTs were performed with a 64-channel multidetector row CT in 27 patients (17 women and 10 men; age range 32-82 years) who were diagnosed with CRC involving the sigmoid and rectum between August 2006 and November 2007. All patients underwent surgery without pre-operative chemotherapy or radiation therapy. Dynamic perfusion CTs were performed for 65 seconds after intravenous injection of contrast medium (100 mL, 300 mg of iodine per mL, 5 mL/sec). Before surgery, blood flow (BF), blood volume, mean transit time (MTT), and permeability-surface area product were measured in the tumor. After surgery, one gastrointestinal pathologist evaluated tumor grade and performed immunohistochemical staining using CD 34 to determine MVD in each tumor. The Kruskal-Wallis test was used to compare CT perfusion parameters with tumor grade, and Pearson's correlation analysis was used to correlate CT perfusion parameters with MVD.
  
  
  RESULTS
  In 27 patients with CRC, tumor grading was as follows: well differentiated (n = 8); moderately differentiated (n = 15); and poorly differentiated (n = 4). BF was higher in moderately differentiated CRC than well differentiated and poorly differentiated CRCs (p = 0.14). MTT was shorter in moderately differentiated than well differentiated and poorly differentiated CRCs (p = 0.039). The MVD was greater in poorly differentiated than well differentiated and moderately differentiated CRCs (p = 0.034). There was no significant correlation between other perfusion parameters and tumor grade. There was no significant correlation between CT perfusion parameters and MVD.
  
  
  CONCLUSIONS
  BF and MTT measurement by perfusion CT is effective in predicting moderately differentiated CRCs. However, perfusion CT is limited in distinguishing well differentiated and poorly differentiated CRCs. Pre-operative perfusion CT does not reflect the MVD of CRCs.
authors.affiliation: Department of Diagnostic Radiology, Chonnam National University Medical School, Chonnam National University Hwasun Hospital, Hwasun 519-763, Korea.
authors.forename: Jin Woong
authors.initials: JW
authors.lastname: Kim
authors.forename: Yong Yeon
authors.initials: YY
authors.lastname: Jeong
authors.forename: Nam Kyu
authors.initials: NK
authors.lastname: Chang
authors.forename: Suk Hee
authors.initials: SH
authors.lastname: Heo
authors.forename: Sang Soo
authors.initials: SS
authors.lastname: Shin
authors.forename: Jae Hyuk
authors.initials: JH
authors.lastname: Lee
authors.forename: Young Hoe
authors.initials: YH
authors.lastname: Hur
authors.forename: Heoung Keun
authors.initials: HK
authors.lastname: Kang
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D003287:Contrast Media; D005260:Female; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D060787:Neoplasm Grading; D009389:Neovascularization, Pathologic / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide