1. detection & characterization
Liver masses
detection & characterization
Dr.Ahmed Refaey
FRCR

2. Detection of liver masses
* arterial phase imaging
* portal venous phase
* equilibrium phase

3. Characterization of liver masses
Hypervascular lesions
Hypovascular lesions
Scar
Capsule
Calcification
Fat
Hemorrhage
Cystic components
Retraction of liver capsule
Peripheral enhancement & progressive fill in

4. Detection of liver masses

5. Minority of tumors contain calcifications , cystic components, fat or hemorrhage and will be detected on NECT.
When we give IV contrast, it is important to understand that there is a dual blood supply to the liver.
Normal parenchyma is supplied for 80% by PV & only for 20% by hepatic artery, so it will enhance in the portal venous phase.
All liver tumors however get 100% of their blood supply from hepatic artery , so when they enhance it will be in arterial phase

6. Small HCC in cirrhotic liver , not visible on NECT , clearly visible in arterial phase, and not visible in portal venous phase.

7. In the arterial phase hypervascular tumors will enhance via the hepatic artery , when normal liver parenchyma does not yet enhances , because contrast is not yet in the portal venous system.
These hypervascular tumors will be visible as hyperdense lesions in a relatively hypodense liver
However when the surrounding liver parenchyma starts to enhance in the portal venous phase , these hypervascular lesions may become obscured.

8. In the portal venous phase hypovascular tumors are detected when the normal liver parenchyma enhances maximally.
These hypovascular tumors will be visible as hypodense lesions in a relatively hyperdense liver.

9. In the equilibrium phase at about 10 minutes after contrast injection , tumors become visible, that either loose their contrast slower than the normal liver , or wash out their contrast faster than normal liver parenchyma. These lesions will become either relatively hyperdense or hypodense to the normal liver

10. Above: arterial phase showing hypervascular FNH
Middle: portal venous phase showing hypovascular metastases
Down: equilibrium phase showing relatively dense cholangiocarcinoma

11. Arterial phase imaging

12. Optimal timing and speed of contrast injection and type of CT scanner are very important for good arterial phase imaging.

13. Optimal timing

14. Hypervascular tumors will enhance optimally at 35 seconds after contrast injection (late arterial phase)

15. A patient who underwent two phases of arterial imaging at 18 and 35 seconds .
In the early arterial phase we nicely see the arteries , but we only see some irregular enhancement within the liver .
In the late arterial phase, we can clearly identify multiple tumor masses.

16. Notice that in the late arterial phase, there has to be some enhancement of the portal vein .
The only time that an arterial phase is needed is when you need an arteriogram , for instance as a roadmap for chemoembolization of a liver tumor.

17. Speed of contrast injection

18. For arterial phase the best results are with an injection of 5 ml/sec

19. Patient with liver cirrhosis and multifocal HCC injected at 2
Patient with liver cirrhosis and multifocal HCC injected at 2.5 ml/sec and at 5 ml/sec.
At 5 ml/sec. there is far better contrast enhancement and better tumor detection.

21. Type of CT scanner

22. If you have a single slice scanner , it will take about 20 seconds to scan the liver.
For late arterial phase imaging 35 sec. is the optimal time , so you start at about 25 seconds and end at about 45 seconds.
However if you have 64 multislice scanner , you will be able to examine the whole liver in 4 seconds , so you start scanning at about 33 seconds.

24. Tripple Phase Helical CT
Axial C+ CT Arterial Phase
Axial C+ CT Portal Venous Phase
Axial C+ CT Hepatic Venous Phase
Contrast Injection
Arterial
Portal Venous
Hepatic Venous 15 30 45 60 75
Time (sec)
Foley, WD. Multiphase Hepatic CT with a Multirow Detector CT Scanner (175):

25. Portal venous phase

26. Portal venous phase imaging work on the opposite idea
Portal venous phase imaging work on the opposite idea . We image the liver when it is loaded with contrast through the portal vein to detect hypovascular tumors.
The best moment to start scanning is at about 75 sec.,so this is a late portal phase , because enhancement of portal vein already starts at 35 sec in the late arterial phase.
Late portal venous phase is also known as hepatic phase because there already must be enhancement of hepatic veins . If you don’t see enhancement of hepatic veins , you are too early.

27. Hypovascular metastases seen as hypodense lesions in late portal venous phase

28. Liver metastases cancer colon

29. Equilibrium phase

30. Starts when contrast is moving away from the liver and the liver starts to decrease in density .
This phase begins at about 3-4 minutes after contrast injection and imaging is best done at 10 minutes after contrast injection.

31. This phase can be valuable if you are looking for:
1- fast tumor washout in hypervascular tumors
2- retention of contrast in blood pool like in hemangioma
3- retention of contrast in fibrous tissue in capsule ( HCC )or scar tissue ( cholangiocarcinoma or FNH )

32. 1- fast tumor washout in hypervascular tumors like HCC

33. 2- retention of contrast in the blood pool as in hemangioma

34. 3- retention of contrast in fibrous tissue in capsule ( HCC ) or scar tissue (cholangiocarcinoma , FNH)

36. Relative hyperdense lesions in the delayed phase
Fibrous tissue that’s well organized and dense is very slow to let iodine or gadolinium in.
Once contrast gets in however, it is equally slow to get back out in the equilibrium phase.
So when the normal liver parenchyma washes out, the fibrous component of the tumor will look brighter than the background liver tissue.

37. Small cholangiocarcinoma not visible in portal venous phase , but seen as relative hyperdense lesion in the equilibrium phase.

38. Relative hypodense lesions in delayed phase
In the delayed phase, malignant tumors ( like HCC ) , the tumor is washed out more than the surrounding liver parenchyma .
But benign tumors typically will not show this kind of wash out , but will stay isodense with liver parenchyma or some times more dense, in the equilibrium phase.
These benign lesions don’t have enough neoplastic neovascularity to have a fast wash out.

39. HCC in a cirrhotic liver
HCC in a cirrhotic liver. Notice fast wash out in equilibrium phase compared to surrounding liver parenchyma.

40. Blood pool and hemangioma
Normally when we look at lesions filling with contrast, the density of these lesions is always compared to the density of the liver parenchyma.
In hemangiomas, however you should not compare the density of the lesion to the liver but to the bloodpool

41. This means that the areas of enhancement in a hemangioma should match the attenuation of the appropriate vessels { bloodpool } at all times.
So, in the arterial phase the enhancing parts of the lesion must have almost the same attenuation value as the enhancing aorta.
While in the portal phase, it must match the attenuation value of the portal vein . And so in venous or delayed phase.

42. So, if it does not match the bloodpool in every single phase of contrast enhancement FOREGET the diagnosis of a hemangioma.

44. Hemangioma in non-enhanced CT, late arterial, late portal venous, and equilibrium phase. Notice that the attenuation of the hemangioma matches the bloodpool in every single phase.

46. Flash filling hemangioma in unenhanced, arterial & portal venous phase
Flash filling hemangioma in unenhanced, arterial & portal venous phase . Notice it matches the bloodpool.

47. Incidental hyper vascular lesions
Hemangioma
Focal nodular hyperplasia ( FNH )
Adenoma
Hepatocellular carcinoma ( HCC )
Fibrolamellar hepatocellular carcinoma
Hypervascular mtastases

48. It is important to differentiate between “touch” and “don’t touch” lesions.
Benign “don’t touch” hypervascular tumors include hemangioma, FNH, small adenoma.
“touch lesions” iclude large adenoma ( more than 5 cm ) and malignant tumors like HCC , fibrolamellar HCC and metastases.

50. Benign hypervascular lesions

51. Hemangioma

52. Hemangioma Bloodpool and hemangioma
Normally when we look at lesions filling with contrast, the density of these lesions is always compared to the density of the liver parenchyma.
In hemangiomas, however you should not compare the density of the lesion to the liver but to the bloodpool

53. This means that the areas of enhancement in a hemangioma should match the attenuation of the appropriate vessels { bloodpool } at all times.
So, in the arterial phase the enhancing parts of the lesion must have almost the same attenuation value as the enhancing aorta.
While in the portal phase, it must match the attenuation value of the portal vein . And so in venous or delayed phase.

54. So, if it does not match the bloodpool in every single phase of contrast enhancement , foreget the diagnosis of a hemangioma.

56. Hemangioma in non-enhanced CT, late arterial, late portal venous, and equilibrium phase. Notice that the attenuation of the hemangioma matches the bloodpool in every single phase.

57. Hemangiomas less than 1 cm frequently demonstrate immediate homogenous enhancement , isodense to aorta.
Hemangiomas larger than 1 cm generally show slow centripetal spread of nodular enhancement

59. Flash filling hemangioma in unenhanced, arterial & portal venous phase
Flash filling hemangioma in unenhanced, arterial & portal venous phase . Notice it matches the bloodpool.

60. Giant hemangioma with scar tissue
Giant hemangioma with scar tissue. Notice that the enhancement matches the bloodpool in all phases, central scar is hypodense on NECT & stays hypodense.

61. Progressive fill in
The lesion definitely has some features of hemangioma like nodular enhancement in the arterial phase & progressive fill in portal venous & equilibrium phase.
In portal venous phase however the enhancement is not as bright as the enhancement of portal vein . The conclusion must be that this lesion doesn’t match blood pool in all phases , so it can’t be hemangioma.
So progressive fill in is a non-specific feature of that can be seen in many other tumors like metastases or cholangiocarcinoma.
The delayed enhancement in this lesion is due to fibrotic tissue in a cholangiocarcinoma & is a specific feature of this tumor

62. Rim enhancement
The enhancement of a hemangioma starts peripheral. It is nodular or globular & discontinuous.
Rim enhancement is continuous peripheral enhancement is never hemangioma.
Rim enhancement is a feature of malignant lesions , especially metastases.
Left: rim enhancement in breast carcinoma
Right: nodular discontinuous enhancement in hemangioma

63. Atypical hemangioma

64. Hemangioma on US

65. Hemangioma on dynamic MRI will show the same enhancement characteristics as on contrast enhanced CT

67. Focal nodular hyperplasia FNH

68. Non-neoplastic, hyperplastic response to a congenital vascular malformation.
At late arterial phase, FNH typically presents with bright homogenous enhancement , but less intense than the aorta with a hypodense central scar.
Smaller (<3cm) FNH , often lack a central scar.
At portal phase, FNH is often isoattenuating to the normal liver and may be difficult to delineate.
Delayed phase often shows hyperattenuation of central scar due to late opacification of fibrous components ( or due to the AVM scar )
No calcification, inhomogenity or capsule should be seen in FNH

69. Best diagnostic clue: brightly and homogeneously enhancing mass in arterial phase on CT or MRI with delayed enhancement of the central scar.
Central scar containing AVM
Central scar seen in 2/3 of large and 1/3 of smal FNH.
No malignant transformation
No association with oral contraceptives.
Nuclear study: normal or increase uptake {only FNH contains kuffer cells that cause increase uptake in 9% of cases }…….pathognomonic
Classic FNH looks like a cross section of an orange ( central scar, radiating septa )

73. Hemangioma & FNH

75. FNH seen as hypervascular lesion in the late arterial phase & isodense in the portal venous phase . No scar was seen.

76. T2W, T1W without gadolinium and a delayed phase after gadolinium.

77. Adenoma

78. Best diagnostic clue: spherical well defined hypervascular and heterogenous mass due to fat & hemorrhage .
Symptomatic in 80%-abdominal pain- ( FNH asymptomatic in 80%)
98% in yoyung females taking oral contraceptives
Not seen in males unless on anabolic steroids or with glycogen storage disease.

83. Adenoma showing capsule in delayed phase

84. Female with acute abdominal pain
On portal phase, hypodense hepatic lesion with hemorrhage adjacent to it, extending subcapsularly.

85. Fat in adenoma

86. Hemorrhage in adenoma

87. Malignant hypervascular lesions

88. Hepatocellular carcinoma HCC

89. Any hypervascular lesion in a cirrhotic liver is hepatocellular carcinoma untill proven otherwise.
HCC may be solitary, multifocal or diffusely infiltrating.
Large HCC typically have a mosaic appearance due to hemorrhage & fibrosis.

90. HCC is a silent tumor, so if patients don’t have cirrhosis or hepatitis C , you will discover them in a late stage.
They tend to be large with mozaic pattern , a capsule , hemorrhage and necrosis.
HCC become isodense or hypodense to liver in the portal venous phase due to fast wash-out
On delayed images, the capsule and sometimes septa demonstrate prolonged enhancement.

91. Large HCC with mozaic pattern in a non cirrhotic liver

93. Cirrhotic liver with hypervascular , inhomogenous lesion.
The inhomogenous enhancement and partial capsule are helpful for the diagnosis of HCC

94. Small HCC in cirrhotic liver not visible on NECT , clearly visible on arterial phase, and not visible in portal venous phase

95. HCC in cirrhotic liver , notice fast wash out in equilibrium phase compared to surrounding liver parenchyma

96. Axial C+ CT: Arterial Phase
PS: Triple Phase CT
Axial C- CT
Axial C+ CT: Arterial Phase
Film Findings:
Nodular liver
No discrete lesions
Early hyperenhancing lesion

97. PS: Triple Phase CT Axial C+ CT: Portal Venous Phase
Axial C+ CT: Delayed Phase
Film Findings:
Quick washout of enhancing lesion
Hypoenhancing lesion with peripheral rim of enhancement

98. ??

99. In the arterial phase we see two hypervascular lesions
In the arterial phase we see two hypervascular lesions. Now do not just concentrate on the images, where you see the lesions best. You have to look at all the other images, because they give you the clue to the diagnosis. The upper images show a lesion that is isodens to the liver on the NECT. In the arterial phase there is enhancement, but not as dense as the bloodpool. In the portal venous phase the lesion is again isodense to the surrounding liver parenchyma and you can't see it. If you only had the portal venous phase you surely would miss this lesion. The lower images show a lesion that is visible on all images. You see it on the NECT and you could say it is hypodens compared to the liver. Does this help you? No, not in the least. However if you look at the bloodpool, you will notice that on all phases it is as dense as the bloodpool. So we have a HCC in the right lobe on the upper images and a hemangioma in the left lobe on the lower images. The key is to look at all the phases.

100. HCC & PV thrombosis
Many patients with cirrhosis have portal venous thrombosis and many patients with HCC have thrombosis. These are two common findings and they can be coincidental. It is very important to make the distinction between just thrombus and tumor thrombus. First, if you have a malignant thrombus in the portal vein, it will always enhance and you'll see it best in arterial phase. Secondly, if you have a malignant thrombus in the portal vein, it will increase the diameter of the vessel. Sometimes a tumor thrombus may present with neovascularity within the thrombus .

101. Above : diffusely enhancing tumor thrombus in HCC with portal venous thrombosis.
Down: tumor thrombus with vessels within the thrombus

103. Fibrolamellar HCC

104. Large hpervascular , heterogenously enhancing,lobulated mass in a normal, non-cirrhotic liver in young adult
Central fibrotic scar in 60%
Calcification in 70% of cases
Normal alpha fetoprotein (increased in HCC)

106. Non enhanced image , a fibrolamaellar HCC usually presents as a big mass with central calcification.

107. FLC in late arterial phase , central calcification & heterogenous enhancement .
Delayed phase with hypodense central scar

109. Hypervascular metastases

110. Characteritics of hypervascular metastases
-a hyper vascular 1ry tumor like renal cell carcinoma, endocrine tumors( thyroid-islet cell – carcinoid) & some breast carcinoma
-often co-existing hypo and hypervascular metastases.
-larger lesions are often inhomogenous due to central necrosis.

111. Hypervascular metastasis
Renal cell carcinoma
Islet cell tumors of pancreas
Thyroid carcinoma
Carcinoid
Malignant melanoma
Choriocarcinoma
Pheochromocytoma
15 % of cancer breast

112. Hypervascular metastases with typical peripheral enhancement

113. Peripheral enhancement in metastases from breast carcinoma

114. Hypervascular metastases

115. Hypervascular metastases cancer breast

116. Characterization of liver masses

117. Scar
Calcification
Capsule
Fat
Blood
Retraction of liver capsule

118. Scar Fibrolamellar HCC ……………Fibrous tissue
Focal nodular hyperplasia …… AVM
Fibrolamellar HCC ……………Fibrous tissue
Cavernous hemangioma …….. Fluid
HCC
cholangiocarcinoma

119. Focal nodular hyperplasia

120. Fibrolamellar HCC

121. Hemangioma

122. Calcification Metastases Fibrolamellar HCC Cholangiocarcinoma
hemangioma

123. Calcified mestastases ca ovary

124. Calcified metastases

125. Fibrolamellar HCC

126. Capsule
Hepatocellular carcinoma “ HCC “
Adenoma
Biliary cystadenoma

127. HCC

128. Adenoma

129. Fat
Adenoma
HCC
Metastatic liposarcoma
Angiomyolipoma

130. Adenoma

131. Blood
HCC
Adenoma

132. HCC

133. Adenoma

134. Retraction of liver capsule
Cholangiocarcinoma
Breast cancer metastases

135. Cholangiocarcinoma

137. Cancer breast metastases

138. Hepatic Cyst Film Findings: Axial C+ CT
Film Findings:
Sharply demarcated, non enhancing, water-dense cyst.

139. Focal Nodular Hyperplasia
Axial C+ CT
Film Findings:
Enhancing lesion with central filling defect (central scar)

140. Hepatocellular Adenoma
Axial C+ CT
UpToDate: Hepatic Adenoma
Film Findings:
Multiple hypoenhancing heterogenous lesions
Enhancing hepatic veins

141. HCC: MR Imaging Variable intensity on T1 and T2 weighted imaging
Axial T1 Weighted MR Precontrast
Axial T1 Weighted MR Arterial Phase
Axial T1 Weighted MR Portal-phase
Variable intensity on T1 and T2 weighted imaging
Early arterial phase enhancement
Quick washout
Rim enhancement of fibrous capsule in portal/delayed phases

142. Liver Metastasis (Colonic Adenocarcinoma)
Axial C+ CT
Film Findings:
Multiple hypoenhancing heterogenous lesions

143. Liver Abscess Film Findings: Axial C+ CT
Film Findings:
Well demaracated hypoenhancing lesion
Rim of increased enhancement relative to central region

144. A Walk Through The Differential Diagnoses:

145. Lesions
Classical CT Findings PS
Hepatic Cyst
Sharply demarcated wall, water density, non-enhancing
Hemangioma
Peripheral filling in of contrast over time
“Light Bulb Sign” on T2 MRI
Focal Nodular Hyperplasia (FNH)
Early filling in arterial phase with central filling defect (scar)
Hepatocellular
Adenoma
Variable, central changes due to hemorrhage often seen
Metastasis
Mostly multiple low attenuation lesions, rim enhancement without “filling in”
Well demarcated hypodense areas with peripheral enhancement, may see gas
Abscess
Hepatocellular Carcinoma (HCC)
Early arterial enhancement, fast washout, delayed fibrous capsule enhancement

146. References

147. The frequency and significance of small (less than or equal to 15 mm) hepatic lesions detected by CT EC Jones, JL Chezmar, RC Nelson and ME Bernardino Department of Radiology, Emory University School of Medicine, Atlanta, GA American Journal of Roentgenology, Vol 158, ,
Prevalence and Importance of Small Hepatic Lesions Found at CT in Patients with Cancer Lawrence H. Schwartz, MD, Eric J. Gandras, MD, Sandra M. Colangelo, MD, Matthew C. Ercolani, BS and David M. Panicek, MD Radiology. 1999;210:71-74.
Small 'indeterminate' lesions on CT of the liver: a follow-up study of stability P J Robinson, MB, FRCP, FRCR, P Arnold, BSc and D Wilson, MSc Clinical Radiology Research Unit and Medical Physics Department, St James's University Hospital, Beckett Street, Leeds LS9 7TF, UK British Journal of Radiology (2003) 76,

148. Small hypoattenuating hepatic lesions at Contrast-enhanced CT: Prognostic importance in patients with breast cancer. George A. Krakora, MD et al Radiology 2004; 233:
Benign hepatic tumours and tumour like conditions in men. by Karhunen PJ. J Clin Pathol Feb;39(2):183-8.
Introduction. In: Tumors of the liver and intrahepatic bile ducts. Page1-7. Atlas of tumor pathology, AFIP, Washington DC, by Robert L. Craig
Fibrolamellar Hepatocellular Carcinoma: Imaging and Pathologic Findings in 31 Recent Cases Tomoaki Ichikawa, MD, Michael P. Federle, MD, Luigi Grazioli, MD, Juan Madariaga, MD, Michael Nalesnik, MD and Wallis Marsh, MD Radiology. 1999;213:

149. Thank you