ECR 2018 TOPIC PACKAGE
Hepatocellular carcinoma (HCC) is the most common type of liver cancer, accounting for 80-90% of all cases of liver cancer. It is the fifth most common cancer and the third leading cause of cancer-related deaths around the world. As HCC occurs in 90% of the cases in patients with chronic liver disease, screening is indicated in those patients having compensated cirrhosis. Several guidelines have been implemented to help the practitioner to manage the patients during the screening, when a nodule is detected and to decide the optimal treatment in patients with HCC. Among the HCC guidelines which are the most used: AASLD, EASL, Japanese, Korean, and Asia-Pacific ones, there are common features. All agree : (i) on the noninvasive diagnosis of HCC using contrast-enhanced CT or MR imaging with two hallmarks: hypervascularisation on arterial-phase and wash-out on portal and/or delayed phase in lesions larger than one centimeter; (ii) on the role of liver biopsy when diagnosis cannot be achieved with imaging. Yet they differ in many other issues: stratification according to lesion size, first-line imaging modality, role of hepatobiliary MR contrast agents, and role of contrast-enhanced ultrasound. These differences are explained by the different prevalence of HCC worldwide and the different goals of diagnostic performance (high specificity or high sensitivity).
LI-RADS is a comprehensive system for imaging HCC in adults with cirrhosis or other risk factors for HCC. It provides standardized terminology with precise definitions and illustrations for screening and surveillance using US, diagnosis and staging using CT, MRI, and CEUS, and treatment response assessment using CT and MRI. It addresses the entire spectrum of lesions and pseudo lesions encountered in the cirrhotic liver as well as the full range of malignant neoplasms associated with chronic liver disease. This lecture will review LI-RADS terminology, interpretation, and reporting and explain why standardization is needed for clinical care, research, and education.
Hepatocellular carcinoma (HCC) poses a burden on global health. As HCC typically has a poor prognosis with a 5-year survival rate of only 28.6%, it is of paramount importance to achieve the earliest possible diagnosis of HCC and to recommend the most up-to-date optimal treatment strategy in order to increase the survival rate of patients who develop this disease. HCC is commonly diagnosed using dynamic CT and/or dynamic MRI without histological confirmation, on the basis of a characteristic arterial enhancement and portal venous or delayed phase washout. Indeed, the noninvasive diagnosis of HCC in high-risk patients by typical imaging findings alone is widely adopted in major practice guidelines for HCC. HCC usually presents with typical imaging characteristics but at times can present with a wide spectrum of atypical appearances. Familiarity with unusual presentations and their imaging findings is critical to ensuring prompt, accurate diagnosis and treatment. Moreover, while imaging techniques have markedly improved in detecting small liver lesions, they often detect incidental benign liver lesions and non-hepatocellular malignancy that can be misdiagnosed as HCC. The common mimickers of HCC in the cirrhotic liver include nontumorous arterioportal shunts, rapidly enhancing hemangiomas, intrahepatic mass-forming type cholangiocarcinoma (CC), angiomyolipomas, focal inflammatory liver lesions and focal nodular hyperplasia-like nodules. Among them, it is important to recognize the suggestive imaging findings for intrahepatic CC as the management of CC is largely different from that of HCC. Recognition of the typical imaging findings of common HCC mimickers can reduce false-positive HCC diagnosis.
Multiphasic CT and MRI allow non-invasive diagnosis of hepatocellular carcinoma in cirrhotic patients. Moreover, they are able to stage the tumour burden to choose the most appropriate treatment for each patient. Furthermore, they have a role in the follow-up of; (1) indeterminate nodules such as LI-RADS 3 and (2) treated HCC nodules to confirm the effectiveness of treatment or to detect residual tumour or recurrence. LI-RADS is a classification system that allows; (1) predicting with CT and MR the likelihood that a lesion is HCC in patients with chronic liver disease or cirrhosis and (2) standardising terminology among different centers.
Non invasive criteria for the diagnosis HCC ≥10 mm in patients with liver cirrhosis are based on the developement of neoangiogenesis and on the progressive reduction of portal supply within the tumour, leading to the characteristic arterial wash-in and portal wash-out pattern detected on dynamic CT/ MR studies performed with extracellular contrast agentes (CA). Imaging criteria have a sensitivity of 60% and a specificity close to 100% for the diagnosis of small HCC. When RM is obtained with gadoxetic acid, the arterial and early portal phases demonstrate also the typical wash-in/wash-out pattern of HCC. In the transitional and hepatobiliary phases, another key imaging is found, the hyposignal intensity of close to 90% of HCCs compared to the surrounding liver parenchyma, based on the progressive reduction/absence of the expresion of organic anion transporting polypeptides (OATPs) during the hepatocarcinogenesis process. LI-RADS can be applied on CT, on MR independenly of the CA used, and also on contrast enhanced ultrasound. The sensitivity, specificity and interobserved concordance of the stanadardised imaging interpretation do not have strong proscpective data availble. Early diagnosis is the only way to improve the outcome of patients with HCC. Up to now, the active work-up for the diagnosis of HCC is recommended for new liver lesion ≥10 mm detected in the context of surveillance programmes. A confident imaging diagnosis of HCC in smaller lesions is limited and treatment of such a tiny possible pre-malignant but not confirmed HCC lesions is not recommended to avoid overdiagnosis and overtreatment.
Besides the top three malignant (HCC, CCC, metastases) and the top three benign liver tumours (haemangioma, FNH, adenoma), there is a large variety of rare entities and subtypes, which can be demanding regarding their imaging diagnostics. In this session, a number of cases will be presented to illustrate the typical and also some challenging findings of focal liver lesions, which the radiologist should know, always keeping in view the potentially severe consequences of the radiologist’s judgement for patient management.
Differential diagnosis and management decisions of pancreatic tumours are based on a mixture of clinical and laboratory information and imaging findings involving multiple modalities. The lecture will familiarize the delegates with the main challenges and future trends in the diagnosis of pancreas tumours, differential diagnosis with pancreas inflammation, and in identifying features that may help to select surgical candidates.
Claude B. Sirlin
San Diego, United States