J Korean Radi이 Soc 1998; 38: 659-666

Differentiation of Hepatocellular Carcinoma from Intrahepatic Cholangiocarcinoma as the Cause of Biliary 0 bstruction :

Value ofDynamic CT During the Hepatic Arterial Phasel

June-Sik Cho, M .D., Dae-Hong Kim, M.D. , Kyung-Sook Shin, M.D., Jin-Keun Kwak, M.D.

Purpose : To evaluate the usefulness of dynamic CT during the hepatic arterial phase with rapid IV injection of contrast material in distinguishing hepatocellular carcinorr베HCC) from intrahepatic cholangiocarcinoma (ICAC) as the cause ofbili­ary obstruction.

Materials and Methods : We retrospectively reviewed two-phase dynamic in­cremental CT or helical CT findings in 22 patients with intrahepatic duct obstruc­tion secondary to pathologically proven HCCs (n = 12) or ICACs(n = 10). Two-phase CT scans were obtained 20 - 45 seconds (hepatic arterial phase) or 2 minutes (equi­librium phase) after the initiation of a bolus injection of contrast material(5mL/sec , 150mL). The enhancement patterns of tumors, as seen on two-phase images, were classified as hypo- , iso-, or hyperattenuated, relative to surrounding liver parenchyma. Two-phase images were compared and correlated with pathologic findings.

Results : During the hepatic arterial phase , diffuse high-enhancement was seen in nine HCCs (75 %) and partial enhancement in three (25 %); five (50 %) of the ten ICACs were h ypodense and five (50 %) were hypodense with peripheral enhance­ment. During the equilibrium phase, however, all HCCs were h ypodense and cap­sular enhancement was seen in four cases(33.3 %). All ICACs were hypodense with mild peripheral or central heterogeneous enhancement. Contrast enhancement patterns of HCCs during the hepatic arterial phase were significantly different (p < .0001) from those ofICACs.

Conclusion : Our results suggest that dynamic CT during the hepatic arterial phase, with rapid IV injection of contrast material, is useful for the differentiation ofHCC from ICAC as the cause ofbiliary obstruction.

Index words : Liver neoplasms, CT Bile d ucts, stenosis or 0 bstruction Computed tomography(CT), contrast enhancement

If conventional contrast-enhanced CT is used , hep­atocellular carcinoma (HCC) can be confused with intrahepatic cholangiocarcinoma (ICAC) with or with­out bile duct invasion. Despite remarkable recent improvements in the diagnostic tools involved, HCC with intrahepatic duct dilatation is, therefore, often still incorrectly diagnosed as ICAC(l , 2). It has been

'Departmcnt ofDiagnostic Radiology , Chungnam University College of Medicine Received October 6, 1997 ; Accepted March 6, 1998

Address reprint requests to: June-Sik Cho. M.D. , Department of Diagnostic

Radiology , Chungnam University HospitaL ~ 640 Daesa- Dong, Joong-Ku ,

Taejon 301-040 , Korea. Te l. 82-42-220-7333 Fax.82-42-253-006 1

reported, however, that if contrast-enhanced dynamic CT or dynamic MR imaging is used , contrast enhance­ment patterns of HCCs and ICACs are significantly dif­ferent(3 - 8). If dynamic CT with rapid IV injection of contrast material is performed during the hepatic ar­terial phase, it is therefore possible to differentiate HCC with bile duct obstruction from ICAC.

Conventional CT or MRI findings of HCCs with bile duct involvement have recently been reported(2, 9), but to our knowledge, description of the differential contrast-enhanced dynamic CT findings of ICAC and

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June-Sik Cho. et af : Differentiation of Hepatocellular Carcinoma from Intr하lepatiC Cholar빙iocarcinoma as the Cause of Biliary Obstruction

HCC with intrahepatic duct obstruction have not been published. The purpose ofthis study was to determine the usefulness of dynamic CT during the hepatic ar­terial phase, with rapid IV injection of contrast ma­teriaL in distinguishing HCC from ICAC as the cause of intrahepatic biliary obstruction.

Materials and Methods

Between October 1992 and February 1997, liver son­ography was performed for the purpose of screening patients with clinically suspected hepatic tumors. In order to characterize these lesions, two-phase in­cremental or helical CT was performed; in 12 patients with pathologically proven HCCs, intrahepatic duct obstruction was diagnosed on the basis of cholangiog­raphic, sonographic, and CT findings. As a comparison group for evaluating the differences as seen on two­phase dynamic CT between ICAC and HCC, we selected 18 patients with pathologically proven ICACs; they had undergone two-phase dynamic CT scans of the liver due to hepatic tumors. Of the 18, ten who were diagnosed by cholangiography, sonography, and CT as suffering from ICAC with intrahepatic duct obstruc­tion were included in this study. The remaining eight, who had ICACs without biliary obstruction, were excluded.

Eight of the 12 patients with HCCs were men and four were women, their mean age was 59 (range, 42 - 73) years. Among the ten patients with ICACs, eight were men and two were women; their mean age was 65 (range, 46 - 86) years.

Pathologic proof of HCC or ICAC was obtained by sonography-guided percutaneous core biopsy using an 18-20-gauge cutting needle. Bile duct obstruction sec­ondary to HCCs was confirmed by a cholangiogram

(percutaneous\ transhepatic cholangiography in five patients, or endoscopic retrograde cholangiography in four) and in the remaining three, bile duct obstruction was diagnosed on the basis of sonographic and CT findings.

To evaluate the enhancement patterns of lesions, a11 22 patients received a uniphasic IV injection of con­trast material. A total of 150mL of non-ionic contrast medium (iodine 300mg/mL, Iopromide; Schering, Ber­lin, Germany) was administered with a power injector at a rate of 5 mL/second for 30 seconds. For IV injection of contrast material into the antecubital vein, an 18-20-gauge sheath needle was used . The higher bolus injec­tion ofnonionic contrast material was well tolerated by all patients and there were no side effects.

In six patients, two-phase dynamic incremental CT scanning ofthe liver was performed with a Xpeed scan­ner (Toshiba Medical System, Tokyo, Japan) at 120 kVp and 150 mAs , while in 16 patients, two-phase heli cal CT scanning of the liver was performed with a HiSpeed advantage scanner (General Electric Medical System, Milwaukee, USA) at 120 kVp and 250 - 280 mAs. Hepatic arterial phase images were obtained 20 - 45 seconds after the initiation of IV in jection of a bolus of contrast material. For hepatic arterial phase imaging with incremental CT, the lesion was localized by precontrast CT scanning ofthe liver. When lesions were isodense on precontrast CT scans, sonographic findings were used to localized the lesion. Hepatic ar terial phase scanning with incremental CT was perfor med with a 2.7-second scanning time and a 1.6-second interscan delay, and contiguous 5- or lO-mm collima­tion. Five contiguous scans with a single 25-second breath-hold were obtained at the lesion site ofthe liver as seen on precontrast CT or sonogram.

Hepatic arterial phase scanning with helical CT was

Table 1. Contrast Enhancement Patterns of Hepatocellular Carcinomas with Bile Duct Invasion (n = 12) and Intrahepatic Cholangiocarcinoms (n = 10) on Two-Phase Dynamic CT

Contrast Enhancement Patterns ICAC(n=10) HCCs (n=12)

Arterial phase Hyperattenuat디ion

Diffuse Partial Peripheral

Hypoattenuation Equilibrium phase Hypoa값ttenuation

Hypoattenuation with capsular enhancement Hypoattenuation with mild peripheral enhancement Hypoattenuation with mild heterogeneous enhancement

QJ

1j

nu

nu

O

O

----

-

8

4

0

0

O

O

4

6

HCC : hepatocellular carcinoma, ICAC : intrahepatic cholangiocarcinoma, n : number ofpatient

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J Korean Radiol Soc 1998; 38 : 659 - 666

performed with a l-second scan, 1: 1 pitch, 7-mm collimation, and 7-mm reconstruction. For the entire liver, 25 continuous scans with a single 25-second breath-fold were obtained. Equilibrium phase scan­ning was performed 2 - 4 minutes after the initiation of IV injection of a bolus of contrast material. For equilib rium phase imaging, 20 contiguous scans from the dia­phragmatic dome to the inferior pole of the kidney were obtained with lO-mm collimation and lO-mm in­terval.

HCCs were s이itary in eight patients and satellite nodules were present in four. ICACs were solitary in eight patients and satellite nodules were present in two. In cases with multiple satellite nodules, the num­ber and size of satellite lesions were not recorded be­cause of lack of pathologic confirmation of these lesions.

Contrast enhancement of HCCs and ICACs was classified as hypo-, iso- , or hyperattenuated, relative to enhancement of surrounding li ver parenchyma as seen on two-phase images . Each lesion was separately eval­uated for homogeneity or heterogeneity of enhance­men t, patterns of contrast enhancement(diffuse , par-

A

C

tial or peripheral), tumor margin(well- or ill-defined), and the presence or absence of late capsular enhance­ment. Capsular enhancement regarded as lesion showed thin membrane-like enhancement. Two-phase dynamic CT images in 12 patients with HCCs and ten with ICACs were retrospectively reviewed by two radiologists(C.J.S. , K.D.H.), who reached a consensus .

Two-phase CT findings were compared and correl­ated with histopathologic findings and clinical man­ifestations including the level of serum α-fetoprotein and total bilirubin. Liver cirrhosis and portal vein thrombosis were diagnosed on the basis of images obtained by sonography, CT, and clinical manifesta­tions.

Fisher’s exact test was used to test for differences in enhancement patterns between HCCs and ICACs; a p value of < .05 was considered statistically significant.

Results

The maximum diameter of 12 HCCs ranged from 3 to 13(mean, 7.1)cm. Nine of these HCCs were in the right hepatic lobe and three were in the left lobe; seven were

B

Fig. 1. A 63-year-old woman with hepatocellular carcinoma. A. CT scan during the hepatic arterial phase shows a well-de­fined mass with diffuse high-enhancement (arrows) in the left hepatic lobe and moderate dilatation of the intrahepatic ducts. B. CT scan during the equilibrium phase shows a hypodense mass with capsular enhancement(arrowheads). C. CT scan during the hepatic arterial phase at the lower level ofthe liver shows a dilated common hepatic duct filled with a highly enhancing mass (arrow) representing intraluminal tumor extension into the common hepatic duct .

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June-Sik Cho, et al : Differentiation of Hepatocellular Carcinoma from Intrahepatic Cholar맹iocarcinoma as the Cause of Biliary Obstruction

ill-defined and five were well-defined. The enhance ment patterns of HCCs, as seen on two-phase images , are shown in Table 1. During the hepatic arterial phase,

HCCs were hyperdense, with a moderate to marked de­gree of diffuse enhancement (Fig. lA) in nine (75 %) and partial enhancement in three(25 %). In four patien­ts(33.3 %), multiple satellite nodules were also highly enhanced(Fig. 2A). During the equilibrium phase,

however, all HCCs (Figs. lB, 2B) became hypodense and satellite nodules were poorly identified.

Incomplete or complete capsular enhancement (Fig. lB) was seen in four cases (33.3 %). Focal dilatation of intrahepatic d ucts around the tumors, or the diffuse di­latation of both intrahepatic ducts was associated in all 12 patients with HCCs . In four HCCs, intraluminal tumor extension (Fig. 2C) into the extrahepatic duct oc­curred ; three of the four showed high enhancement of

intraluminal tumor (Fig. lC) during the hepatic arterial phase, similar to tha t of primary tumor.

The sizes of ten ICACs ranged from 5 to 10(mean, 6.9) cm in maximum diameter. Five of the ten were in the right hepatic lobe and the others were in the left lobe. Five were relatively well-defined and five were ill-de­fined. The enhancement patterns of ICACs on two­phase images are shown in Table 1. During the hepatic arterial phase, five ICACs (50 %) were hypodeilse (Fig. 3A) and five (50 %) were hypod-ense with peripheral enhancement(Fig. 4A). During the equilibrium phase, however, all ICACs were hypodense with mild periph­eral or central heterogeneous enhancement(Figs. 3B, 4B). No ICACs showed capsular enhancement. Focal or diffuse dilatation of the intrahepatic ducts was seen in all ICACs. Diffuse, mild dilatation ofperipheral intrah­epatic ducts was seen in three cases (30 %) and clon-

A B

Fig. 2. A 58-year-old woman with hepatocellular carcinomas. A. CT scan during the hepatic arterial phase shows a large mass with diffuse high-enhancement in the left hepatic lobe and multiple small satellite nodules with high enhancement (arrowheads) are seen throughout the liver. Note direct tumor extension into the common hepatic duct(arrow). B. CT scan during the equilibrium phase shows an ill-defined hypodense mass (arrows). Multiple satellite nodules are poorly identified because lesions became slightly hypodense or isodense compared with surrounding liver parenchymal enhancement. c. Endoscopic retrograde cholangiogram shows a focal eccentric narrowing (ar­row) ofthe common hepatic duct by tumor invasion.

C

이

, ‘ “

J Korean Radi이 Soc 1998; 38: 659-666

orchiasis was confirmed in the stool examination(Fig 4). During the equilibrium phase, it was difficult to dif­ferentiate HCCs with intrahepatic duct dilatation from ICACs; during the hepatic arterial phase, however, en­hancement patterns ofHCCs with intrahepatic duct ob­struction were significantly different (p (. 0001) from those of ICACs. Additional findings were liver cir­rhosis in ten patients with HCCs and in one with ICAC. Portal vein thrombosis was found in six patients with HCCs and in one with ICAC.

Discussion

Obstructive jaundice has been regarded as an un-

A

Fig. 3. A 57-year-old man with intrahepatic cholangiocarcinoma.

common complication of HCC, with an incidence of 2-8 % in patients with HCCs(l , 2, 10 - 13). HCC­induced biliary obstruction can be caused by direct tumor invasion of intrahepatic ducts, pedunculated tumor extension into the extrahepatic bile ducts , blood clots or necrotic frag-ments from the tumor, and meta­static lymph node compression of the major ducts in the porta hepatis(II - 13). The prognosis of patients with o bstructive jaundice due to HCC seems to be poor, since most tumors with major bile duct invasion are large and infiltrative. In order to effectively plan man­agement strategies, the identification of specific causes of obstructive jaundice is important(2)

On CT scans, intrahepatic duct dilatation secondary

B

A. CT scan during the hepátic arterial phase shows a hypodense mass (arrow) in the medial segment ofthe left hepatic lobe B. CT scan during the equilibrium phase shows a well-defined hypodense mass (arrow) with mild heterogeneous enhance­ment and moderate dilatation of both intrahepatic ducts.

A B Fig. 4. A 56-year-이d man with intrahepatic cholangiocarcinoma and clonorchiasis. A. CT scan dur e mass with peripheral enhancement (arro에leads) in the left hepatic lobe and marked dilatation ofthe left intrahepatic d ucts due to hilar extension oftumor B. CT scan d uring the equilibrium phase shows an ill-defined hypodense mass with mild peripheral enhancement(arrowhead­s). Note mild , diffuse dilatation ofthe right int rahepatic ducts and clonorchiasis was confirmed in the stool examination.

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June-Sik Cho. et al : Differentiation of Hepatocellular Carcinoma from Intrahepatic Cholangi∞arcinoma as the Cause of Biliary Obstruction

to HCC is suggested when intrahepatic duct dilatation is associated with marked elevation of serum α­

fetoprotein level and a well-delineated, encapsulated intrahepatic mass(L 2). Since, however, the enhance­ment patterns of both tumors are similar and intrah­epatic duct dilatation is a common CT feature ofICAC, infiltrative HCC with bile duct invasion may be diffi­cult to differentiate from ICAC on conventional con­trast-enhanced CT scans.

HCCs are hypervascular tumors which are supplied by hepatic arteries(3 - 5) . They become maximally hyperdense during the hepatic arterial phase of dy­namic CT and rapidly less dense during the portal ve­nous phase, and then gradually become hypodense during the delayed phase(3 - 6). Dynamic CT during the hepatic arterial phase, with rapid bolus injection of contrast material and early initiation of scanning, has therefore been used for the detection and characteriza­tion of HCCs(5 , 6). To characterize hepatic tumors, we performed two-phase dynamic incremental or helical CT during the hepatic arterial and equilibrium phases, with rapid IV injection of contrast material. During the heaptic arterial phase, nine ofthe 12 HCCs (75 %) show­ed diffuse high-enhancement before adequate en­hancement of surrounding liver parenchyma, and three (25 %) were partially enhanced. In addition, mul­tiple, enhanced, small satellite nodules were readily detectable in four cases. During the equilibrium phase, however, all HCCs showed hypoattenuation relative to liver parenchyma, and because the lesions became isodense or slightly hypodense, multiple satellite nodules were poorly depicted. The enhancement patterns of HCCs with biliary obstruction, as seen on two-phase dynamic CT scans, were similar to those of HCCs without biliary obstruction.

ICACs contain abundant stroma and fibrous tissue; on contrast-enhanced CT scans, this tumor therefore appears as an irregular mass with low attenuation, mild contrast enhancement at the periphery during the early phase, and delayed or prolonged, homogeneous enhancement due to extensive interstitial space during the delayed phase(3, 6, 14- 16). This enhancement of ICACs during the delayed phase, which is obtained 10 - 20 minutes after contrast administration, is d ue to slow wash-in and wash-out of contrast material in fi­brous tissue(3, 16). Dynamic studies of ICAC using CT or MR have reported that this tumor show

five cases(50%). During this phase, enhancement patterns of HCCs were, therefore, significantly differ­ent from those ofICACs. During the equilibrium phase, all ICACs were hypodense with mild peripheral or cen­tral heterogeneous enhancement, and no capsular en­hancement was seen. Because delayed-phase images were not obtained for more than ten minutes, we did not observe prolonged or delayed enhancement, a characteristic finding ofICAC. During the equilibrium phase, eight HCCs(66.7 %), which showed ill-defined hypod-ense infiltrating masses without capsular en­hancement, were therefore difficult to differentiate from ICACs. However, four HCCs (33.3 %) showed complete or incomplete capsular enhancement, and this helped distinguish HCCs from ICACs.

Although we have encountered a small number of HCCs with biliary obstruction, the frequency of capsu­lar enhancement was similar to that of HCCs without such obstruction. Soyer et al.(2), however, reported that encapsulation was absent in all ten HCCs with intrahepatic duct dilatation and suggested that a lack of encapsulation in patients with HCCs might favor bile duct involvement. This difference between their res­ults and ours might be explained by the fact that the frequency of HCC encapsulation among Asian popula­tions is significantly higher than among non-Asians (17, 18).

On conventional contrast-enhanced CT, intralumin­al filling defects of the bile duct due to blood clots and/or necrotic tumor tissue are difficult to differen­tiate from pedunculated HCC( lO). Intrabiliary mass en­hancement, however, as seen on contrast-enhanced CT scans, indicates extension of HCC rather than a blood clot(9). In our series , intraluminal tumor extension into the bile duct, as confirmed by cholangiography, was seen in four patient~ with HCCs. In three ofthese cases,

the tumor was highly enhanced during the hepatic ar­terial phase, resembling an enhanced primary tumor. We believe that for the diagnosis of intrabiliary exten­sion ofHCC, such a finding is useful.

Our study has certain limitations; two-phase dy­namic CT findings were evaluated in which intrahepat­ic duct dilatation was secondary to HCCs or ICACs - a relatively small number of cases. In our series, all 12 HCCs showed a mild to marked degree of diffuse or par­tial hyperattenuation during the hepatic arterial phase. Other studies, however, have reported that during t

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and others is due to our restricted number of cases.

Another limitation was that we obtained equilibrium

phase instead of the delayed phase images; the latter

are accepted as being ideal for the characterization of

cholangiocarcinoma.

In our study, capsular enhancement ofHCCs during

the equilibrium phase was helpful in differentiating

these from ICACs, but it was difficult to differentiate

unencapsulated infiltrative HCCs from ICACs. During

the hepatic arterial phase, however, most HCCs were

highly enhanced and most ICACs were poorly

enhanced except in cases with peripheral enhance­

ment. Contrast enhancement patterns of HCCs during

the hepatic arterial phase were significantly different

from those o fICACs. In addition, hepatic arterial-phase

images helped detect small satellite nodules and

intrabiliary tumor extension of HCCs. In conclusion, our results suggest that dynamic CT during the hepatic

arterial phase, with rapid IV injection of contrast ma­

terial, is useful for the differentiation of HCC from

ICAC as the cause ofbiliary obstruction.

References

1. Kojiro M. Kawabata K. Kawano Y. Shirai F. Takemoto N. Nak­

ashima T. Hepatocellular carcinoma presenting as intrabile duct

tumor growth: a c1inicopathologic study of 24 cases. Cancer

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2. Soyer P. Sibert A. Laissy JP. Intrahepatic bile duct dilatation

seco ndary to hepatocellular carcinoma: CT features in 10 pat­ients. Abdom Imaging 1995; 20 ‘ 11 4- 117

3. Baron RL. Understanding and optimizing use of contrast ma­

terial for CT of the liver. AJR 1994; 163: 323-331

4. Ohashi L Hanafusa K. Yoshida T. Small hepatocellular carcin­

omas: two-phase dynamic incremental CT in detection and evaluation. Radi%gy 1993; 189: 851-855

5. Oi H. Murakami T. Kim T. Matsushita M. Kishimoto H.

Nakamura H. Dynamic MR imaging and early-phase helical CT

for detecting small intrahepatic metastases of hepatocellular carcinoma . AJR 1996; 166 : 369-374

6. Cho JS. Kwag JK. Oh YR. Han SD. Song CJ . Detection and

characterization of hepatocellular carcinoma ’ value of dynamic CT during the arterial dominant phase with uniphasic contrast

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and pathologic correlation. J Comput Assist Tomogr 1993 ; 17 ‘

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8. Fan ZM. Yamashita Y. Harada M. et al. Intrahepatic cholangioc

arcinoma: spin-echo and contrast-enhanced dynamic MR imag­

ing. AJR 1993 ; 161: 313-317

9. Soyer P. Laissy JP. Bluemke DA. Sibert A. Menu Y. Bile duct

involvement in hepatocellular carcinoma ’ MR demonstration

Abdom Imaging 1995 ; 20: 118-121

10. Kubota Y. Seki T. Kunieda K. et a1. Biliary endoprosthesis in

bile duct obstruction secondary to hepatocellular carcinoma Abdom Imaging 1993;18:70-75

11. Lee NW. Wong KP. Siu KF. Wong J . Cholangiography in hepatocell비ar carcinoma with obstructive jaundice. C/in Radio/

1984;35: 119-123

12. Lau W-Y. Leung JWC. Li AKC. Management of hepatocellul값

carcinoma presenting as obstructive jaundice. Am J Surg 1990;

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0/0밍 1979; 130: 7-13

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angiocarcinoma: comparison of MRI with CT. Abdom Imaging

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15. Takayasu K. Ikeya S, Mukai K. Muramatsu y , Makuuchi M, Hasegawa H. CT of hilar cholangiocarcinoma: late contrast en­

hancement in six patients. AJR 1990; 154: 1203- 1206

16. Lacomis JM, Baron RL, 이iver III JH, Nalesnik MA, Federle

MP. Cholangiocarcinoma: delayed CT contrast enahncement

patterns. Radi% ，밍 1997 ; 203 : 98-104

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parative study of US, CT, and MRI. Gastrointest Radio/ 1992; 17

: 245-249

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대한방시선의학회지 1998; 38: 659-666

담관폐쇄의 원인으로 간세포암과 간내 담관암의 감별에 었어 간동맥기 역동적 CT의 유용성1

l 충남대학교 의과대학 진단방사선과학교실

조 준 식·김 대 홍·신 경 숙·곽 진 근

목 적 : 담관폐쇄의 원인으로 간내 담관암으로부터 간세포암을 구별하는데 있어 조영제를 급속 정맥 주입하

면서 시행하는 간동액기 역동적 CT의 유용성을 평가하고자 하였다.

대상 및 방법 : 간내 담관폐쇄를 동반하였으며 병리조직적으로 확진된 12예의 간세포암과 10예의 간내 담관암

환자를 대상으로 이중시기 역동적 CT 혹은 나선식 CT소견을 후향적으로 분석하였다. 150mL의 조영제를 초당

5mL의 속도로 주입하면서 조영제 주입시작후 20-45초에 간동맥기 영상을 얻고 2분에 조직평형기 영상을 얻는

이중시기 역동적 CT 흑은 나선식 CT를 시행하였다. 종양의 조영증강 양상은 주위 간실질과 비교하여 저， 동등，

고음영으로분류하여 。1중시기 영상을버교하였다.

결 과 : 간동맥기에서 12예의 간세포암은 모두 고음영을 보였으며， 이중 9예 (75%)는 전반적인 현저한 조영증

강을， 3예 (25% )는 부분적 인 조영증강을 보였다. 반면에 10예의 간내 담관암은 모두 저음영을 보였고， 이중 5예

(50%)는 종양 주변부의 조영증강을 보였다. 조직평형기에서 간세포암은 12예 모두 저음영을 보였고， 이중 4예

(33.3%)는피막의 조영증강을보였다.반면에 간내 담관암의 경우 10예 모두저음영을보였고병변의 주변부혹

은 중심부에서 약하고 불균일한 조영증강을 보였다. 간동맥기에서 간세포암의 조영증강 양상은 간내 담관암과

유의성 있는 차이를 보였다(p<.OOOl).

결 론 : 조영제를급속정맥 주입하면서 시행하는간동맥기 역동적 CT는담관폐쇄의 원인으로간내 당관암으

로부터 간세포암을 감별하는데 있어 유용한 방법으로 생각된다.

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