Transient hepatic attenuation differences

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[edit] Discussion

  • CT finding: Transient hepatic attenuation differences (THAD)
  • MRI finding: Transient hepatic intensity differneces (THID)
  • Areas of parenchymal enhancement visible during the hepatic artery phase that are caused by the dual hepatic blood supply.
  • Association with focal liver lesions.
  • Four pathogenetic mechanisms:
    • Directly by a siphoning effect (lobar multisegmental shape)
    • Portal hypoperfusion (sectorial shape) due to portal branch compression or infiltration
    • Thrombosis resulting in a portal branch blockade
    • Flow diversion caused by an arterioportal shunt.
  • Compensatory relationships between two liver sources of blood supply so that arterial flow increases when portal flow decreases as a result of communication among the main vessels, sinusoids, and peribiliary venules that open in response to autonomic nervous system and humoral factors activated by liver demand for oxygen and metabolites.

[edit] Imaging Findings

[edit] Images

Patient #1

[edit] See Also

[edit] External Links

Goldminer: THAD

[edit] References

Colagrande, Stefano, Centi, Nicoletta, Galdiero, Roberta, Ragozzino, Alfonso. Transient Hepatic Intensity Differences: Part 1, Those Associated with Focal Lesions. Am. J. Roentgenol. 2007 188: 154-159