[Radiologic diagnosis before and after liver transplantation]

The main function of imaging procedures before liver transplantation is the exclusion of factors that may either constitute contraindications to surgery or necessitate a modification of the operation technique. Ultrasound and MRI are the modalities best suited for this purpose. After transplantation, imaging procedures are required mainly for diagnosis of and differentiation, in particular, between vascular and biliary complications, rejection, and infection, since these postoperative complications very often cannot be reliably differentiated on the basis of clinical and laboratory parameters alone. As vascular disturbances can vary widely in their presentation and can mimic other complications, duplex Doppler sonography plays a dominant role in clarification of the perfusion status of the graft. If infection is suspected, ultrasound generally has to be supplemented by other imaging procedures such as CT or MRI; if these techniques reveal suggestive lesions, a fine-needle aspiration is mandatory in most cases. Invasive procedures such as angiography or PTC are now applied only in selected cases, especially if an intervention is contemplated. Rejection cannot be reliably diagnosed by any of the imaging techniques and still requires biopsy.