Andreu F Costa1,2, Dilkash Kajal3, André Pereira3, Mostafa Atri3. 1. Joint Department of Medical Imaging, University Health Network and Mount Sinai Hospital, University of Toronto, Munk Building, 1c-571, 585 University Avenue, Toronto, Ontario, Canada, M5G 2N2. andreu.costa@uottawa.ca. 2. Department of Diagnostic Radiology, QE II Health Sciences Centre - VG Site, Dalhousie University, 1276 South Park Street, Halifax, Nova Scotia, B3H 2Y9, Canada. andreu.costa@uottawa.ca. 3. Joint Department of Medical Imaging, University Health Network and Mount Sinai Hospital, University of Toronto, Munk Building, 1c-571, 585 University Avenue, Toronto, Ontario, Canada, M5G 2N2.
Abstract
OBJECTIVES: To assess the significance of fat in the radiofrequency ablation (RFA) zone of hepatocellular adenomas (HCA), and its association with tumoral fat and hepatic steatosis. METHODS: The radiological archive was searched for patients with ablated HCAs and follow-up magnetic resonance imaging between January 2008 and June 2014. Age, sex, risk factors and duration of clinical and imaging follow-up were recorded. Pre-RFA imaging was assessed for tumour size, intra-tumoral fat and steatosis. Post-RFA imaging was reviewed for size, enhancement and intra-ablational fat. Intra-ablational fat was classified as peripheral, central or mixed; the association of these distributions with steatosis and tumoral fat was assessed using Fisher's exact test. RESULTS: Sixteen patients with 26 ablated HCAs were included. Fat was present in 23/26 (88 %) ablation zones. Only 1/26 (4 %) showed serial enlargement and enhancement suggestive of residual disease; the enhancing area did not contain fat. All remaining ablations showed involution and/or diminishing fat content without suspicious enhancement (mean follow-up, 27 months; range, 2-84 months). The peripheral and mixed/central patterns of intra-ablational fat were associated with steatosis (P = 0.0005) and tumoral fat (P = 0.0003), respectively. CONCLUSION: Fat in the ablation zone of HCAs is a common finding which, in isolation, does not indicate residual tumour. KEY POINTS: • Fat in the RFA zone of HCAs is a common finding on MRI. • The distribution of fat is associated with hepatic steatosis and intra-tumoral fat. • In isolation, intra-ablational fat of treated HCAs does not indicate residual tumour.
OBJECTIVES: To assess the significance of fat in the radiofrequency ablation (RFA) zone of hepatocellular adenomas (HCA), and its association with tumoralfat and hepatic steatosis. METHODS: The radiological archive was searched for patients with ablated HCAs and follow-up magnetic resonance imaging between January 2008 and June 2014. Age, sex, risk factors and duration of clinical and imaging follow-up were recorded. Pre-RFA imaging was assessed for tumour size, intra-tumoralfat and steatosis. Post-RFA imaging was reviewed for size, enhancement and intra-ablational fat. Intra-ablational fat was classified as peripheral, central or mixed; the association of these distributions with steatosis and tumoralfat was assessed using Fisher's exact test. RESULTS: Sixteen patients with 26 ablated HCAs were included. Fat was present in 23/26 (88 %) ablation zones. Only 1/26 (4 %) showed serial enlargement and enhancement suggestive of residual disease; the enhancing area did not contain fat. All remaining ablations showed involution and/or diminishing fat content without suspicious enhancement (mean follow-up, 27 months; range, 2-84 months). The peripheral and mixed/central patterns of intra-ablational fat were associated with steatosis (P = 0.0005) and tumoralfat (P = 0.0003), respectively. CONCLUSION:Fat in the ablation zone of HCAs is a common finding which, in isolation, does not indicate residual tumour. KEY POINTS: • Fat in the RFA zone of HCAs is a common finding on MRI. • The distribution of fat is associated with hepatic steatosis and intra-tumoralfat. • In isolation, intra-ablational fat of treated HCAs does not indicate residual tumour.
Authors: Aldo Carnevale; Fabio Pellegrino; Alberto Cossu; Anna Maria Ierardi; Gian Carlo Parenti; Gianpaolo Carrafiello; Melchiore Giganti Journal: Med Oncol Date: 2020-03-19 Impact factor: 3.064