Ausnalas Radio1 1992: 36:34-36
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Hepatocellular Carcinoma: MR Imaging THANIT SLNGCHAROEN*, ORACHART UDOMPMCH, KA”MAR CHAKKAPHAK Department of Radiology Bumrungrad Hospital and * Pramongkutklao Hospital, Bangkok, Thailand J
ABSTRACT Thirty patients with hepatocellular carcinoma (HCC) were examined by MRI. Distinctive fmdings of HCC such as the presence of fatty degeneration, a capsule, mosaic pattern, daughter nodules and tumor thrombi in major veins were noted in 6,13,1,10 and 9 cases or 20%, 43%,3%,33% and 30% respectively. INTRODUCTION Hepatocellular carcinoma (HCC) is a common hepatic tumour in the Far East. To detect HCC, we use mainly ultrasound and computed tomography, supported by serum alpha-fetoprotein. Recently magnetic resonance imaging (MRI) has been described as equal or superior to C T in the detection and evaluation of liver tumours (1,2). In this paper we report our experience with h4R findings in 30 cases of HCC. MATERIALS AND METHODS I)llring the past two y m medical records of patients who underwent MRI of the liver were reviewed and 30 cases of HCC were obtained. There were 27 men and 3 women, 35-75 years old with a mean age of 53 years. HCC was histologically confirmed in 17 cases. The remaining 13 were diagnosed clinically by tumour markers, clinical information and characteristic findings on ultrasound and CT.MR imaging was performed with a superconducting magnet operating at 0.5 T (MR Max: General Electric, Milwaukee). Images were obtained by a spin-echo (SE)technique, performed with TR/TE = aoO/25 TlWI (for T1 weighted image) and 2000/40-80 PD & T2WI (for T2 weighted image) sequences. The section thickness was 1Omm. with intersection gap of lmm. Gradient echo technique with TR/rE = 500/20 and flip angle - 30 was performed in most cases. Images were acquired with a 256 x 256 matrix and displayed in a 5 12 x 512 matrix.The body coil was used with a field of view of 35 or 42cm. MR findings were reviewed for morphological appearance of HCC. signal intensity in both T1 and T2 weighted images, the presence of capsules, intratumoral septa, daughter nodules and tumour thrombi in hepatic and portal veins.
RESULTS We divided HCC into well-defined (Figure 1) and diffuse types (Figure 2) based on the imaging appearance.
FIGURE 1A - TI weighted image showing a well defmed hypointense mass with a hypointensecapsule in right hepatic lobe.
Twenty seven belonged to the former and three to the latter group. The size of the main tumour in the welldefined type ranged from 2 to 12cm. Most cases (24/30) were hypointense in TlWI (for T1 weighted image) (Figure 1A) and hyperintense in T2WI (for T2 weighted image) (Figure 1B) in relation to normal liver tissue. Four cases were hyperintense and two cases isointense on T l W I (for T1 weighted image) (Figure 3). Tumour capsules were noted in 13 cases or 43% (Figure 1). Intratumoral septa (Figure 2) were observed in one case. Daughter nodules or intrahepatic metastases (Figure 4) were seen in 10 cases or 33%. Tumour thrombi (Figure 5 ) were present in 9 cases (30%). DISCUSSION HCC has characteristic gross pathologic features that are of great help in differentiating HCC from other hepatic tumours. These include fatty degeneration, pseudocapsules, intratumoral septa, daughter nodules and tumor thrombi in portal or hepatic veins (1,3,4,2). In this study most HCC were hypointense in TlWI (for T1 weighted image). In 6 cases (20%),the tumors were hyper or isoinSubmitted for publication on: 27th November,1990 Resubmitted for publication on: 23rd April. 1991 Accepted for publication on: 5th July. 1991 Australasian Radiology, Vol.36, No. I , February, 1992
HEPATOCELLULAR CARCINOMA: MR IMAGING
FIGURE 1B -Tumor becomeshyperintense in T2 weighted image.
FIGURE 2 -T2Weighted image showing diffusc kpakma in both lobes of ha.Multiple qtatiaiarmosaic prttcm is noad.
FIGURE 4A - TIW (for TI weighted image) shows an ill-defined hypointense mass in left hepatic lobe (anow).Flow void signal in right and middle hepatic veins and N C (arrow heads) indicates patmcy of these vessels. Absence of flow void sigrul in left hepatic vein indicates tumor involvement. FIGURE 3 - TI weighted image showing hyperintense tumor due to fatty degeneration.
tense in TlWI (for T1 weighted image). This has been explained by fatty degeneration of HCC which was not observed in other common hepatic tumors such as metastases, hemangiomas, adenomas or focal nodular hyperplasia (2). Only rare fatty tumors such as lipoma or hamartoma should be hyperintense in TlWI (for T1 weighted image). The capsule in HCC is histopathologically a pseudocapsule. In our series tumor capsules were noted in 13/30 cases or 43%. comparable to the incidence in Japanese series (3,4). Tumor capsules may be occasionally noted in hepatic adenoma but not in hemangioma or metastasis (2). Australasian Radidom. Vol. 36, No. I , February, 1992
Intratumoral septa, also composed of fibrous tissue but thinner than pseudocapsules, divide a tumor mass into multiple compartments or mosaic pattern. This finding was present in only one case in our series. The daughter nodule is one of the common findings in HCC. Detection of the nodule is very important not only for the diagnosis of HCC but also for treatment planning. Daughter nodules are better demonstrated on “2 weighted images (2) as shown in figure 4B. Tumor thrombus in large veins is another distinctive feature of HCC. Normal intrahepatic vessels show flow
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FIGURE 4B T2W (for T2 WightCd image) showing a lpBe hyperiaW tuma rmsSin kft lobc (m). Multiple dpughmnodules in right kbc.M( seen in TlWl (for T1 weigbkd image) slc well sum now.
FIGURE 5A - GRASS image at the level of hepatic veins, showing bright signal in left and middle hepatic veins (arrows), indicative of normal flow. Absence of bright signal in right hepatic vein and N C indi+ates tumor invasion.
From our experience and recent reports MRI appears to be as good as or better than conventional CT (without the aid of a dynamic study or angiographic technique) in the detection of the main or daughter lesions and determination of extent and characterization of HCC. This is because of good contrast between tumor and liver, ability to image vessels and information concerning T1 and T2. The presence of fatty degeneration, pseudocapsules, intratumoral septa, daughter nodules and tumor thrombi in major veins are highly suggestive of HCC. With the development of fast W techniques and tissue-specific liver contrast, the sensitivity of MRI might be improved and may compete with CT portography or intraoperative sonography in the near future.
REFERENCES Ebara M,Ohto M.Watanahe Y er 01. Diagnosis of small hepatocellular carcinoma: conelation of MR imaging and tumor histologic studies. Radiology 1986,159 371-377. 2. Rummeny E, Weissleder R, Stark DD et al. Rimary liver tumors: diagnosis by MR imaging. Am J Roentgen01 1989; 152: 63-72. 3. Itai Y. Ohtomo K, Furui S er al. M R imaging of hepatocellular carcinoma. Journal of Computer Assisted Tomography 1986 10 (6): 963-%8. 4 Itoh K, Nishimura K,Togashi K et al. Hepatocellular carcinoma: MR imaging. Radiology 1987, 164: 21-25. 1.
FIG-
SB -GRASS image at the level of ponal vein, showing bright signal m left p c d vein (arrow) but M signal in right poltal vein, consisrcm with ri@ paral win thmmbosis.
void signal in TlWI (for T1 weighted image) (Figure 4A.) and bright signal in GRASS images (Figures 5A and B). MRI can demonstrate the patency of hepatic and portal veins clearly by using both TlWI (for T1 weighted image) and GRASS technique without the use of intravenous contrast media and with a sensitivity equal to or greater than
cr.
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Ausmalasian Radiology. Vol. 36, No. 1 February, 1992
1
I
Hepatocellular Carcinoma: MR Imaging THANIT SLNGCHAROEN*, ORACHART UDOMPMCH, KA”MAR CHAKKAPHAK Department of Radiology Bumrungrad Hospital and * Pramongkutklao Hospital, Bangkok, Thailand J
ABSTRACT Thirty patients with hepatocellular carcinoma (HCC) were examined by MRI. Distinctive fmdings of HCC such as the presence of fatty degeneration, a capsule, mosaic pattern, daughter nodules and tumor thrombi in major veins were noted in 6,13,1,10 and 9 cases or 20%, 43%,3%,33% and 30% respectively. INTRODUCTION Hepatocellular carcinoma (HCC) is a common hepatic tumour in the Far East. To detect HCC, we use mainly ultrasound and computed tomography, supported by serum alpha-fetoprotein. Recently magnetic resonance imaging (MRI) has been described as equal or superior to C T in the detection and evaluation of liver tumours (1,2). In this paper we report our experience with h4R findings in 30 cases of HCC. MATERIALS AND METHODS I)llring the past two y m medical records of patients who underwent MRI of the liver were reviewed and 30 cases of HCC were obtained. There were 27 men and 3 women, 35-75 years old with a mean age of 53 years. HCC was histologically confirmed in 17 cases. The remaining 13 were diagnosed clinically by tumour markers, clinical information and characteristic findings on ultrasound and CT.MR imaging was performed with a superconducting magnet operating at 0.5 T (MR Max: General Electric, Milwaukee). Images were obtained by a spin-echo (SE)technique, performed with TR/TE = aoO/25 TlWI (for T1 weighted image) and 2000/40-80 PD & T2WI (for T2 weighted image) sequences. The section thickness was 1Omm. with intersection gap of lmm. Gradient echo technique with TR/rE = 500/20 and flip angle - 30 was performed in most cases. Images were acquired with a 256 x 256 matrix and displayed in a 5 12 x 512 matrix.The body coil was used with a field of view of 35 or 42cm. MR findings were reviewed for morphological appearance of HCC. signal intensity in both T1 and T2 weighted images, the presence of capsules, intratumoral septa, daughter nodules and tumour thrombi in hepatic and portal veins.
RESULTS We divided HCC into well-defined (Figure 1) and diffuse types (Figure 2) based on the imaging appearance.
FIGURE 1A - TI weighted image showing a well defmed hypointense mass with a hypointensecapsule in right hepatic lobe.
Twenty seven belonged to the former and three to the latter group. The size of the main tumour in the welldefined type ranged from 2 to 12cm. Most cases (24/30) were hypointense in TlWI (for T1 weighted image) (Figure 1A) and hyperintense in T2WI (for T2 weighted image) (Figure 1B) in relation to normal liver tissue. Four cases were hyperintense and two cases isointense on T l W I (for T1 weighted image) (Figure 3). Tumour capsules were noted in 13 cases or 43% (Figure 1). Intratumoral septa (Figure 2) were observed in one case. Daughter nodules or intrahepatic metastases (Figure 4) were seen in 10 cases or 33%. Tumour thrombi (Figure 5 ) were present in 9 cases (30%). DISCUSSION HCC has characteristic gross pathologic features that are of great help in differentiating HCC from other hepatic tumours. These include fatty degeneration, pseudocapsules, intratumoral septa, daughter nodules and tumor thrombi in portal or hepatic veins (1,3,4,2). In this study most HCC were hypointense in TlWI (for T1 weighted image). In 6 cases (20%),the tumors were hyper or isoinSubmitted for publication on: 27th November,1990 Resubmitted for publication on: 23rd April. 1991 Accepted for publication on: 5th July. 1991 Australasian Radiology, Vol.36, No. I , February, 1992
HEPATOCELLULAR CARCINOMA: MR IMAGING
FIGURE 1B -Tumor becomeshyperintense in T2 weighted image.
FIGURE 2 -T2Weighted image showing diffusc kpakma in both lobes of ha.Multiple qtatiaiarmosaic prttcm is noad.
FIGURE 4A - TIW (for TI weighted image) shows an ill-defined hypointense mass in left hepatic lobe (anow).Flow void signal in right and middle hepatic veins and N C (arrow heads) indicates patmcy of these vessels. Absence of flow void sigrul in left hepatic vein indicates tumor involvement. FIGURE 3 - TI weighted image showing hyperintense tumor due to fatty degeneration.
tense in TlWI (for T1 weighted image). This has been explained by fatty degeneration of HCC which was not observed in other common hepatic tumors such as metastases, hemangiomas, adenomas or focal nodular hyperplasia (2). Only rare fatty tumors such as lipoma or hamartoma should be hyperintense in TlWI (for T1 weighted image). The capsule in HCC is histopathologically a pseudocapsule. In our series tumor capsules were noted in 13/30 cases or 43%. comparable to the incidence in Japanese series (3,4). Tumor capsules may be occasionally noted in hepatic adenoma but not in hemangioma or metastasis (2). Australasian Radidom. Vol. 36, No. I , February, 1992
Intratumoral septa, also composed of fibrous tissue but thinner than pseudocapsules, divide a tumor mass into multiple compartments or mosaic pattern. This finding was present in only one case in our series. The daughter nodule is one of the common findings in HCC. Detection of the nodule is very important not only for the diagnosis of HCC but also for treatment planning. Daughter nodules are better demonstrated on “2 weighted images (2) as shown in figure 4B. Tumor thrombus in large veins is another distinctive feature of HCC. Normal intrahepatic vessels show flow
35
-
FIGURE 4B T2W (for T2 WightCd image) showing a lpBe hyperiaW tuma rmsSin kft lobc (m). Multiple dpughmnodules in right kbc.M( seen in TlWl (for T1 weigbkd image) slc well sum now.
FIGURE 5A - GRASS image at the level of hepatic veins, showing bright signal in left and middle hepatic veins (arrows), indicative of normal flow. Absence of bright signal in right hepatic vein and N C indi+ates tumor invasion.
From our experience and recent reports MRI appears to be as good as or better than conventional CT (without the aid of a dynamic study or angiographic technique) in the detection of the main or daughter lesions and determination of extent and characterization of HCC. This is because of good contrast between tumor and liver, ability to image vessels and information concerning T1 and T2. The presence of fatty degeneration, pseudocapsules, intratumoral septa, daughter nodules and tumor thrombi in major veins are highly suggestive of HCC. With the development of fast W techniques and tissue-specific liver contrast, the sensitivity of MRI might be improved and may compete with CT portography or intraoperative sonography in the near future.
REFERENCES Ebara M,Ohto M.Watanahe Y er 01. Diagnosis of small hepatocellular carcinoma: conelation of MR imaging and tumor histologic studies. Radiology 1986,159 371-377. 2. Rummeny E, Weissleder R, Stark DD et al. Rimary liver tumors: diagnosis by MR imaging. Am J Roentgen01 1989; 152: 63-72. 3. Itai Y. Ohtomo K, Furui S er al. M R imaging of hepatocellular carcinoma. Journal of Computer Assisted Tomography 1986 10 (6): 963-%8. 4 Itoh K, Nishimura K,Togashi K et al. Hepatocellular carcinoma: MR imaging. Radiology 1987, 164: 21-25. 1.
FIG-
SB -GRASS image at the level of ponal vein, showing bright signal m left p c d vein (arrow) but M signal in right poltal vein, consisrcm with ri@ paral win thmmbosis.
void signal in TlWI (for T1 weighted image) (Figure 4A.) and bright signal in GRASS images (Figures 5A and B). MRI can demonstrate the patency of hepatic and portal veins clearly by using both TlWI (for T1 weighted image) and GRASS technique without the use of intravenous contrast media and with a sensitivity equal to or greater than
cr.
36
Ausmalasian Radiology. Vol. 36, No. 1 February, 1992
