title: Limited utility of MRA for acute bowel ischemia after portal venous phase CT.
abstract: OBJECTIVE
  Mesenteric ischemia and ischemic colitis are uncommon but potentially life-threatening causes of acute abdominal pain. Portal venous phase computed tomography (CT) is routinely ordered in the emergency room setting for abdominal pain, but subsequent MR angiography may be requested for additional evaluation of the mesenteric vasculature. We compare the concordance of CT and magnetic resonance angiography (MRA) for acute bowel ischemia.
  
  
  METHODS
  Thirty-two patients who underwent contrast-enhanced MRA for bowel ischemia after having undergone CT evaluation within the preceding 2 weeks were identified. A retrospective review of imaging, treatment history, surgical, and pathology reports was conducted. Two radiologists each reviewed the imaging studies in a blinded fashion.
  
  
  RESULTS
  Ten cases of bowel ischemia were confirmed by endoscopy and/or surgical pathology. CT correctly identified bowel findings in all cases. Intraobserver agreement between CT and MRA for all vessels was 0.68 and 0.63, highest for the superior mesenteric artery. Interobserver agreement was 0.74 for MRA and 0.78 for CT. Vascular findings were only directly mentioned in 10 of 32 CT reports (and 7 of 10 cases with confirmed bowel ischemia). MRA only detected two additional or alternative diagnoses.
  
  
  CONCLUSIONS
  Portal venous phase CT and MRA demonstrate a high degree of concordance for vascular evaluation. Reviewed CT examinations were sufficient to assess the patency of the mesenteric vasculature, but vascular findings were not reported in most cases. A direct description within the report may have obviated the request for further MR imaging. MRA adds little value after portal venous CT in assessing bowel ischemia.
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 South Kingshighway Boulevard, Campus Box 8131, Saint Louis, MO, 63110, USA. shettya@mir.wustl.edu.
authors.forename: Anup S
authors.initials: AS
authors.lastname: Shetty
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 South Kingshighway Boulevard, Campus Box 8131, Saint Louis, MO, 63110, USA.
authors.forename: Vincent M
authors.initials: VM
authors.lastname: Mellnick
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 South Kingshighway Boulevard, Campus Box 8131, Saint Louis, MO, 63110, USA.
authors.forename: Constantine
authors.initials: C
authors.lastname: Raptis
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 South Kingshighway Boulevard, Campus Box 8131, Saint Louis, MO, 63110, USA.
authors.forename: Ronald
authors.initials: R
authors.lastname: Loch
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 South Kingshighway Boulevard, Campus Box 8131, Saint Louis, MO, 63110, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Owen
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 South Kingshighway Boulevard, Campus Box 8131, Saint Louis, MO, 63110, USA.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Bhalla
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement; D018810:Magnetic Resonance Angiography; D008297:Male; D065666:Mesenteric Ischemia / Q000473:pathology*; D008643:Mesentery / Q000473:pathology; D008875:Middle Aged; D015588:Observer Variation; D011169:Portal Vein; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media
keywords: Computed tomography; Ischemic colitis; Magnetic resonance angiography; Mesenteric ischemia; Portal venous CT