title: Zebra pattern: a diagnostically challenging hepatic parenchymal enhancement pattern at CT arterial portography.
abstract: OBJECTIVE
  To investigate the effect of arterial injection site and splenic volume on the hepatic zebra pattern seen at computed tomographic (CT) arterial portography.
  
  
  METHODS
  Images from CT arterial portographic examinations, performed via either the splenic artery (SA)(n = 47) or superior mesenteric artery (SMA)(n = 51) in 98 patients, were reviewed. The hepatic parenchymal enhancement pattern was assessed by three blinded reviewers. Splenic volume was determined.
  
  
  RESULTS
  Twenty-two of 98 (22%) CT arterial portographic studies showed a zebra pattern: 10 of 47 (21%) with injection via the SA and 12 of 51 (24%) with injection via the SMA. The mean percentage of hepatic parenchyma with nontumorous perfusion defects was 55% with the zebra pattern versus 12% without (P < .001). For SA injections, the mean splenic volume was lower in patients with the zebra patterns (321 vs 409 cm3, P = .09). For SMA injections, it was higher in patients with zebra patterns (372 vs 291 cm3, P = .10).
  
  
  CONCLUSIONS
  The zebra pattern can cause difficulties in interpreting images. It is due to alternating, well-defined regions of portal venous hyper- and hypoperfusion; it likely has a multifactorial cause and is likely due to technical parameters such as the injection site, the volume of the spleen, and the hemodynamic effects of the tumor.
authors.affiliation: Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Lawrance
authors.forename: V G
authors.initials: VG
authors.lastname: McDermott
authors.forename: E K
authors.initials: EK
authors.lastname: Paulson
authors.forename: M T
authors.initials: MT
authors.lastname: Keogan
authors.forename: D M
authors.initials: DM
authors.lastname: Delong
authors.forename: W C
authors.initials: WC
authors.lastname: Meyers
authors.forename: R C
authors.initials: RC
authors.lastname: Nelson
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007269:Injections, Intra-Arterial; D008099:Liver / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011172:Portography; D012189:Retrospective Studies; D013154:Spleen / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed