Transient hepatic intensity differences (THIDs) are a phenomenon observed on MRI imaging of the liver. They are considered a direct equivalent to transient hepatic attenuation differences (THADs) noted on CT. They may be focal or nonfocal.
A focal THID lesion can arise from four pathological mechanisms
- directly by a siphoning effect (lobar multisegmental shape)
- indirectly by means of portal hypoperfusion (sectorial shape) due to portal branch compression or infiltration
- by thrombosis resulting in a portal branch blockade
- by flow diversion caused by an arterioportal shunt
These can be sectorial, polymorphous or diffuse and can arise from a variety of etiologies.
- 1. Colagrande S, Centi N, Galdiero R et-al. Transient hepatic intensity differences: part 1, Those associated with focal lesions. AJR Am J Roentgenol. 2007;188 (1): 154-9. doi:10.2214/AJR.05.1368 - Pubmed citation
- 2. Colagrande S, Centi N, Galdiero R et-al. Transient hepatic intensity differences: part 2, Those not associated with focal lesions. AJR Am J Roentgenol. 2007;188 (1): 160-6. doi:10.2214/AJR.05.1367 - Pubmed citation