title: Nodule in Liver: Investigations, Differential Diagnosis and Follow-up.
abstract: Conventional ultrasonogram of the abdomen being noninvasive, inexpensive and ubiquitously available is the first imaging modality that raises suspicion of HCC in a patient with chronic liver disease with or without cirrhosis. The lesions in liver particularly nodule are being recognized with increased frequency with the wide spread use of ultrasonogram as the initial investigation and computerized tomography and magnetic resonance imaging subsequently. Any nodule in a cirrhotic liver should be considered as hepatocellular carcinoma until otherwise proved. This approach certainly is helpful in diagnosing HCC at its earliest possible stage to offer meaningful curative measures be it transplant, resection or ablative therapy. After a nodule is detected on ultrasonogram the next imaging modality can be a contrast enhanced study (dynamic CT scan or an MRI) to see if are present or not. Two vital clues for diagnosis of HCC by contrast enhanced imaging are presence of arterial hypervascularity and washout which are considered as "classical imaging features". This sequence of events of arterial uptake followed by washout is highly specific for diagnosis of HCC by imaging. If the features are typical showing classical imaging features (i.e hypervascular in the arterial phase with washout in portal venous or delayed phase) the lesion should be treated as HCC biopsy is not necessary. Nodular lesions showing an atypical imaging pattern, such as iso- or hypovascular in the arterial phase or arterial hypervascularity alone without portal venous washout, should undergo further examinations with another contrast enhanced imaging. Biopsy is advisable for those lesions which do not show classical features on the imaging.
authors.affiliation: Asian Institute of Gastroenterology, Hyderabad, Andhra Pradesh 500082, India.
authors.forename: Padaki N
authors.initials: PN
authors.lastname: Rao
keywords: AASLD, American Association for Study of Liver Diseases; AFP, alphafetoprotein; ALT, alanine aminotransferase; APASL, Asia–Pacific Association for Study of Liver; AST, aspartate aminotransferase; CEA, carcino-embryonic antigen; CEUS, contrast enhanced ultrasound; CT, computerized tomography; DIA, digital image analysis; DW MRI, diffusion weighted magnetic resonance imaging; FDG, fludeoxyglucose; FISH, fluorescent in situ hybridization; FNA, fine needle aspiration; FNH, focal nodular hyperplasia; HBV, hepatitis B virus; HCC, hepatocellular carcinoma; HCV, hepatitis C virus; LDH, lactate dehydrogenase; MDCT, multidetector computerized tomography; MRI, magnetic resonance imaging; PEI, percutaneous ethanol injection; PET, positron emission tomography; PUO, pyrexia of unknown origin; RFA, radio frequency ablation; US, ultrasound; hepatocellular carcinoma; nodule liver; ultrasonogram