MRI of benign and focal liver lesions. Dr Nick Woodward Royal Free London

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1 MRI of benign and focal liver lesions Dr Nick Woodward Royal Free London

2 Introduction Focal liver lesions Benign Characterisation of lesions seen on other modalities Characterisation of benign hepatocellular lesions Malignant Primary liver tumours Hepatocellular carcinoma, cholangiocarcinoma Metastases Others

3 Recent developments New contrast agents Primovist Diffusion

4 Liver cell specific contrast (Primovist Gadoxetic Acid) Taken up by hepatocytes Dynamic phase, later hepatocyte phase Benign lesions Can help differentiate adenoma and FNH Malignant lesions Colorectal metastases

5 Benign lesions Cysts, haemangiomata Adenoma, FNH

6 Haemangioma Hypointense on T1 Hyperintense on T2 (large vascular spaces with slowly flowing blood) Enhancement Type 1: immediate uniform Type 2: peripheral, with filling-in Type 3: peripheral, with central non-enhancement

7 Haemangioma T2 T1 Progressive, high low signal peripheral enhancement

8 Giant haemangioma: incomplete filling-in, even on delayed imaging Haemangioma

9 Focal Nodular Hyperplasia Second most common benign tumour after haemangioma Most commonly seen in women of reproductive age Most cases discovered incidentally Mean diameter 5cm No risk of haemorrhage

10 Focal nodular hyperplasia Characteristic central scar in 80%. Low on T1, high on T2 T2: slightly hyperintense T1: hypo or isointense Marked arterial phase enhancement Isointense on portal venous phase Slightly hyperintense on delayed imaging

11 Adenoma Benign tumour Most commonly seen in women on OCP (also anabolic steroids) Complications: Haemorrhage Rare malignant transformation to HCC Size 1-19cm; mean 3 5cm

12 Adenoma T2: often have some hyperintense components T1: variable, but often have high signal components Most show arterial phase enhancement, becoming isointense on delayed images

13 FNH vs Adenoma May have similar enhancement With Primovist adenoma typically washes out on delayed phase, whilst FNH remains isointense

14 FNH - Primovist Unenhanced T1 Arterial phase Delayed Retains contrast on delayed phase

15 Adenoma - Primovist Washout on delayed phase

16 Adenoma - Primovist

17 Hepatocellular Carcinoma (HCC) 3 rd leading cause of cancer deaths worldwide (18 th most common in UK) Increasingly recognised earlier Diagnostic criteria avoids need for biopsy Treatment algorithm Transplantation criteria

18 HCC diagnostic criteria Arterial phase enhancement and portal venous phase washout in lesion >1cm (EASL 2009 guidelines)

19 HCC treatment algorithm Curative Resection, transplantation Locoregional Ablation Embolisation Systemic chemotherapy

20 HCC transplantation criteria Single tumour <5cm, or up to 5 tumours all <3cm Single tumour >5cm <7cm, and: No evidence of progression over 6/12 No extrahepatic spread No new nodules Can have locoregional / chemotherapy during window NOT IF: Tumour rupture Macrovascular invasion afp>10000 iu/ml

21 HCC typical appearance Arterialisation Washout

22 HCC and vessels Dominant supply of tumour is from hepatic artery May cause arterio-portal shunting (ie early enhancement of adjacent portal vein branch), with no tumour involvement May invade adjacent vessel (portal or hepatic vein) tumour thrombus Has implications for treatment

23 HCC arterioportal shunting Early enhancement of right posterior portal vein branch

24 HCC macrovascular invasion Tumour invasion of vessel. May be relatively subtle, without much enhancement of thrombus

25 HCC macrovascular invasion Same patient, 3 months earlier

26 HCC macrovascular invasion Or more extensive, with occlusion of a division of portal vein

27 HCC macrovascular invasion More extensive, with occlusion and expansion of portal vein And hepatic vein

28 Regenerative nodules Non neoplastic nodules that arise in cirrhotic liver. Typically high signal on T1, with no enhancement. May become dysplastic (arterialised), and eventually malignant (HCC)

29 HCC Treatment - RFA Small lesion, size increase over 6 months

30 HCC Treatment - RFA Arterial phase Portal venous phase

31 HCC Treatment - RFA Post ablation: high signal on T1 (haemorrhage), no enhancement

32 HCC Treatment - embolisation Hcc. Pre TAE Post TAE lesion devascularised (peri-lesional enhancement)

33 HCC Treatment wedge resection HCC pre resection HCC post resection CT

34 HCC Treatment Sorafenib Pre Sorafenib Post Sorafenib

35 Intrahepatic Cholangiocarcinoma May present as small lesion causing duct dilatation, and often dissociation of intrahepatic ducts Or larger mass lesion

36 Intrahep cholangio Small ill-defined slightly T2 hyperintense lesion close to confluence of left and right ducts Dissociation of left and right ducts

37 Intrahepatic Cholangiocarcinoma Larger lesion, more peripherally within liver (more peripheral duct involved)

38 Metastases Liver dominant site for colorectal metastases Potentially resectable / ablatable, therefore important to stage as accurately as possible! Contrast enhanced MRI better than CT. Diffusion restricted bright on DWI Primovist no hepatocytes, therefore lower signal than normal liver

39 Colorectal metastases Surgical resection and ablative techniques improve survival See more, smaller lesions with MR than CT

40 Colorectal metastases Typical appearance slightly T2 hyperintense, peripheral enhancement, restricted diffusion T2 hyperintense peripheral enhancement restricted diffusion

41 Colorectal mets - Primovist T2 T1 Venous phase Delayed

42 Neuroendocrine liver metastases Uncommon tumours arising from fore-, mid- and hindgut (lung, pancreas, small and large bowel) Metastasise to liver Variety of treatments Resection Rarely transplantation Chemotherapy Embolisation, ablation Radio-isotope

43 Neuroendocrine Liver Metastases Variety of appearances Typically hypervascular May be necrotic Variable size

44 Neuroendocrine Liver Metastases Metastic intermediate grade pancreatic NET

45 Neuroendocrine Liver Metastases Same patient showing pancreatic primary

46 Neuroendocrine Liver Metastases Well differentiated low grade metastatic rectal NET

47 Combination of metastases Pattern of enhancement may suggest origin from different primary 2 lesions, similar on T2....and diffusion..but different enhancement Combination of functional imaging and targeted biopsy showed metastatic colorectal and neuroendocrine tumour (from two primaries)

48 Diffusion weighted imaging Helps detect small lesions Breast metastasis. Previous ablation -?edge recurrence

49 Melanin bright on T1 Melanoma metastases T1 T1 Post gad T2 DWI

50 Rarer lesions Histiocytic sarcoma

51 Rarer lesions HEHE hepatic epithelioid hemangioendothelioma

52 Summary benign lesions MRI can characterise most benign lesions Pattern of enhancement Characteristic findings (eg central scar) Primovist in adenoma vs FNH

53 Summary - HCC Characteristic findings of HCC Arterialisation and washout Dysplastic nodules MRI good for assessing vascular complications (which may affect treatment)

54 Summary - metastases MRI particularly useful in colorectal metastases (and others such as neuroendocrine) Use of DWI, Primovist etc In rarer / unusual lesions MRI may help, but biopsy often still needed