title: Non-invasive MR assessment of macroscopic and microscopic vascular abnormalities in the rectal tumour-surrounding mesorectum.
abstract: OBJECTIVE
  To evaluate the MRI macroscopic and microscopic parameters of mesorectal vasculature in rectal cancer patients.
  
  
  METHODS
  Thirteen patients with rectal adenocarcinoma underwent a dynamic contrast-enhanced MRI at 1.5 T using a blood pool agent at the primary staging. Mesorectal macrovascular features, i.e., the number of vascular branches, average diameter and length, were assessed from baseline-subtracted post-contrast images by two independent readers. Mesorectal microvascular function was investigated by means of area under the enhancement-time curve (AUC). Histopathology served as reference standard of the tumour response to CRT.
  
  
  RESULTS
  The average vessel branching in the mesorectum around the tumour and normal rectal wall was 8.2 ± 3.8 and 1.7 ± 1.3, respectively (reader1: p = 0.001, reader2: p = 0.002). Similarly, the tumour-surrounding mesorectum displayed circa tenfold elevated AUC (p = 0.01). Interestingly, patients with primary node involvement had a twofold higher number of macrovascular branches compared to those with healthy nodes (reader1: p = 0.005 and reader2: p = 0.03). A similar difference was observed between good and poor responders to CRT, whose tumour-surrounding mesorectum displayed 10.7 ± 3.4 and 5.6 ± 1.5 vessels, respectively (reader1/reader2: p = 0.02).
  
  
  CONCLUSIONS
  We showed at baseline MRI of rectal tumours a significantly enhanced macrovascular structure and microvascular function in rectal tumour-surrounding mesorectum, and the association of primary mesorectal macrovascular parameters with node involvement and therapy response.
  
  
  CONCLUSIONS
  • Vascular MRI reveals macrovascular and microvascular abnormalities in the rectal tumour-surrounding mesorectum. • Formation of highly vascular stroma precedes the actual tumour invasion. • High macrovascular parameters are associated with node involvement. • Mesorectal vascular network differs for good and poor responders.
authors: Department of Radiology, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, 6202 AZ, Maastricht, Netherlands.
authors: Ewelina
authors: E
authors: Kluza
authors: Department of Radiology, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, 6202 AZ, Maastricht, Netherlands.
authors: Jean-Paul J E
authors: JP
authors: Kleijnen
authors: Department of Radiology, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, 6202 AZ, Maastricht, Netherlands.|Department of Surgery, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, Netherlands.
authors: Milou H
authors: MH
authors: Martens
authors: Department of Pathology, Maastricht University Medical Center, Maastricht, Netherlands.
authors: Dorit
authors: D
authors: Rennspiess
authors: Department of Radiology, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, 6202 AZ, Maastricht, Netherlands.
authors: Monique
authors: M
authors: Maas
authors: Department of Radiology, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, 6202 AZ, Maastricht, Netherlands.
authors: Cécile R L P N
authors: CR
authors: Jeukens
authors: Department of Pathology, Maastricht University Medical Center, Maastricht, Netherlands.
authors: Robert G
authors: RG
authors: Riedl
authors: Department of Pathology, Maastricht University Medical Center, Maastricht, Netherlands.
authors: Axel
authors: A
authors: zur Hausen
authors: Department of Surgery, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, Netherlands.
authors: Geerard L
authors: GL
authors: Beets
authors: Department of Radiology, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, 6202 AZ, Maastricht, Netherlands. beetstan@me.com.
authors: Regina G H
authors: RG
authors: Beets-Tan
mesh_terms: D000230:Adenocarcinoma / Q000098:blood supply* / Q000473:pathology*; D000368:Aged; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000098:blood supply* / Q000473:pathology*; D012007:Rectum / Q000098:blood supply / Q000473:pathology; D054079:Vascular Malformations / Q000473:pathology*
chemical_list: D003287:Contrast Media
keywords: Blood pool imaging; Dynamic contrast-enhanced MRI; Mesorectal vasculature; Neoadjuvant chemoradiotherapy; Rectal cancer