Current status of the imaging modalities in the pre- and postoperative diagnostic workup of liver transplant patients.

Before transplantation, imaging procedures are mainly used to exclude factors which may serve as contraindications, render surgery difficult, or necessitate a modification of the operative technique. In addition, assessment of liver volume is necessary before segmental liver transplantation. Sonography or other cross-sectional imaging modalities are sufficient for these purposes. After transplantation, imaging is principally required in cases with suspected complications. Sonography, including Duplex and Doppler sonography, is an excellent first investigative modality for this purpose in addition to assessment of the clinical and biochemical parameters. Sonography can diagnose not only vascular complications but also biliary and infective complications; the former may also be a concealed cause of the latter. In unclear infections sonography often has to be supplemented by other modalities like CT. In equivocal cases a puncture is indicated. Invasive procedures are necessary in only selected cases, in particular when an intervention is under consideration. At present MR plays a limited role in the diagnostic workup as it rarely offers additional information except in very few cases. The early diagnosis of rejection cannot be reliably made by any of the imaging modalities and is essentially dependent on the biopsy.