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Use of a Combined CT-Angiography System for Demonstration of Correlative Anatomy during Embolotherapy for Hepatocellular Carcinoma
Technical Note
Use of a Combined CT-Angiography System for Demonstration of Correlative Anatomy during Embolotherapy for Hepatocellular carcinoma1 Hideyuki Ishijima, MD Yoshinari Koyama, MD Jun Aoki, MD Tsuyoshi Kawano, MD Takahito Nakajima, MD Hiroshi Ishizaka, MD Keigo Endo, MD
Index terms: Computed tomography, treatment planning Liver neoplasms, localization Liver neoplasms, therapy
JVIR 1999; 10:811-815
From the Department of Diagnostic Radiology, Gunma University Hospital, 3-39-15, Showa-machi, Maebashi, Gunma 371-8511, Japan. Received September 30, 1998; revision requested November 2; revision received December 29; accepted January 4, 1999. Address correspondence to H.I. O SCVIR, 1999
SUPERSELECTIVE transcatheter arterial embolization (TAE) is the favored treatment for patients with a solitary or few hepatic malignant tumors because it permits the delivery of a sufficient amount of the drug and embolization material to the lesions and prevents damage to normal liver parenchyma in segments without tumors (1,2). Recent advances in arterial catheterization technique have now made possible the easy insertion of a catheter tip into the subsegmental arteries of the liver. While the catheter is in the distal branch of the hepatic artery to perform superselective TAE, the existence of tumors in the infused area should be confirmed. This is usually done with conventional angiography or digital subtraction angiography (DSA). However, we encountered difficulties during TAE in lesions hard to visualize on DSA, lesions supplied from multiple hepatic arterial branches, and lesions supplied by parasitic vessels. Recently, a new system consisting of an angiographic apparatus and computed tomography (CT) has been introduced. This system allows repeated CT images to be obtained during arteriography, without moving patients to the CT room (3). To conduct a cross-sectional evaluation of drug distribution from the catheter with CT during arteriography, we performed superselective TAE for hepatocellular carcinomas using this combined system. We present
its clinical use for superselective TAE of hepatocellular carcinoma, emphasizing the usefulness of CT in performing selective arteriography.
I ~ A T E R m SAND MJTl"l'ODS Our system consists of a CT scanner and angiographic apparatus (Somatom Plus 4 P and Multistar T.O.P.; Siemens, Erlangen, Germany) located in the same room (Fig 1).The patient table is mounted on the floor and used for each examination. Fluoroscopy and DSA are performed on the patient table at the fluoroscope/DSA position with the ceiling-mounted angiographic gantry (Fig la). During the CT examination, the patient table slides to the CT position into the floor-mounted CT gantry (Fig lb). Because the patient does not have to move, it takes 1 minute to change the configuration of the system. We performed 50 embolotherapy procedures for hepatocellular carcinomas using this system between April 1998 and October 1998. DSA and TAE were performed from a femoral approach. Diagnostic arteriography, including the celiac trunk (or common hepatic artery) and the superior mesenteric artery for portography, was performed with nonionic contrast medium (Iomeprol [Iomeron 3501; Eisai, Tokyo, Japan) through a 5-F catheter in all patients. Additionally, CT during arterial portography (CTAP)
812
Combined CTIAngiography System for Demonstration of Correlative Anatomy
June 1999 JVIR
a.
b.
Figure 1. The combined system of a CT scanner (Somatom Plus 4/P) and angiographic apparatus (Multistar T.O.P.).A floor-
mounted patient table is compatible for fluoroscope/DSA and CT scan. The ceiling-mounted, C-arm angiographic gantry and floor-mounted CT gantry are included. (a) Configuration for DSA and fluoroscopy. (b) Configuration for CT scan. The patient table slides to the CT position in the CT gantry.
via the superior mesenteric artery and CT during hepatic arteriography (CTHA) via the proper hepatic artery were performed regularly. In some cases, CTHA was performed separately from the right and left hepatic artery because of the variation of the arterial branch. The CTAP and CTHA were performed using volume spiral scan technique covering the whole liver, with 5-mm beam collimation a t 120 kV and 240 mA, 5 m d s e c caudocephalic table movement, and image reconstruction every 5 mm. The contrast medium for CTAP and CTHA was diluted with saline to contain 175 mg IImL and it was infused throughout scanning a t a rate of 2 mLIsec. The scan start delay after contrast material injection was 25 seconds for CTAP, and 7 seconds for CTHA. We directed the patients to hold their breath during CT scanning. It took approximately 7-8 minutes for a single CT examination (CTAP or CTHA) including time to change the system configuration. In the 50 procedures in which TAE was used, 23 cases were determined to be a solitary lesion or few lesions in the same segment by means of diagnostic angiography, CTAP, and CTHA. These lesions were enhanced on CTHA. In these
cases, we advanced the catheter into distal branches, which were expected to be the feeding branches. A 3-F SP catheter (Terumo, Tokyo, Japan) or Microferret (Cook, Bloomington, IN) was used to perform selective catheterization in most cases. After performing a test injection of contrast material into DSA, CT during selective arteriography from the inserted catheter was performed by manually injecting 5-10 mL of the contrast medium (350 mg IImL) throughout scanning. CT during arteriography examined the entire liver using volume spiral scanning in which the scan parameters were the same for CTAP and CTHA (the parameters of the first 12 cases were 10-mm beam collimation a t 120 kV and 220 mA, 10 mmlsec caudocephalic table movement, and image reconstruction every 10 mm). TAE was performed by using a mixture of iodized oil (Lipiodol; Andre Guerbet, Aulnay-sous-Bois, France) and epirubicin hydrochloride (Farmorubicin; Kyowa-Hakko, Tokyo, Japan), followed by gelatin sponge particles (Gelfoam; Upjohn, Kalamazoo, MI). The doses of these materials were determined according to the size and number of the lesions and patients' liver function.
1 RESULTS CT during selective arteriography allowed accurate evaluation of the correlation with the lesions and distribution of the injected contrast material in all 23 cases. In 17 of the 23 cases, we could determine that the lesions were included in the contrast material distribution on CT during selective arteriography and immediately performed superselective TAE (Fig 2). In three of the 17 cases, a part of lesion was not enhanced, and we added embolotherapy from the other feeding branches. We encountered a case of complete obstruction of the right hepatic artery due to previous TAE, and performed CT during selective arteriography from the right inferior phrenic artery and confirmed the enhancement of the intrahepatic lesion. In six of the 23 cases, the tumors were not included in the distribution of the contrast material on CT during selective arteriography (Fig 3). We changed the location of the catheter more proximally or selectively inserted the catheter in other branches and repeated CT during selective arteriography. In these six cases, we used CT during selective
Ishijima et a1
813
Volume 10 Number 6
Figure 2. A 61-year-old man with a solitary hepatocellular carcinoma in segment VII of the right hepatic lobe. (a) Celiac angiogram shows a n inhomogenous contrast enhancement in the subphrenic area (arrow). However, it is difficult to detect tumor neovasculature and recognize the boundary of the lesion. (b)CT during right hepatic arteriography shows a n enhanced lesion in segment VII (arrow). ( c ) Selective angiogram of the branch of the segment VII. I t shows a faint focal enhancement. However, it is difficult to differentiate stained tumor from the summation of hepatic parenchymal stain. (d) CT during selective arteriography from the same catheter location as in c . It confirms that the lesion is strongly enhanced (arrowhead) and included in the distribution of the contrast material. Adjacent liver tissue and a part of the anterior segment are also strongly enhanced from the same branch.
arteriography two or three times in the procedure. In four of the six cases, we could confirm the feeding artery and performed superselective TAE. In two cases, however, we could not insert the catheter into the appropriate branches and performed TAE from
the proximal portion of the lobar artery.
DISCUSSION When the catheter is inserted into the distal branches to perform superselective TAE, it is necessary
to confirm if the hypervascular tumors are present in the embolization area and whether the tumors are fully covered within the embolization area. In hepatocellular carcinomas smaller than 2 cm in diameter, tumor stain is often the only indica-
814
Combined CTIAngiography System for Demonstration of Correlative Anatomy
June 1999 JVIR
Figure 3. An 83-year-old woman with a recurrent hepatocellular carcinoma in segment VIII of the right hepatic lobe. (a) CTAP shows a perfusion defect (arrow) in segment VIII. Some small cysts are noted. (b) Replaced right hepatic angiogram shows a focal contrast material enhancement in the liver just beneath the right hemidiaphragm (arrow). Dense deposition of the iodized oil is seen in the lesion previously treated with TAE from the left hepatic artery (arrowhead). ( c ) Selective angiogram of the subsegmental branch of segment VIII shows a similar focal enhancement in the same place (arrow). (d) CT during selective arteriography from the same catheter location as in c. The lesion (arrow) detected with CTAP is not included in the distribution of the contrast material (Fig 3 continues).
tion (4). However, we occasionally encountered cases in which the tumor stain became invisible a t DSA after the catheter was inserted into the distal branch. We believe that the contrast between the lesions and adjacent liver parenchyma decreased because the adjacent liver parenchyma is also enhanced as strongly as the lesions. In addition, the structural distortion in the surrounding cirrhotic liver produces
various hemodynamic changes and makes an inhomogeneous hepatogram a t angiography (4,5).As a result, it is difficult to detect small hypervascular tumors and recognize the boundary of the tumor clearly on DSA. Therefore, we think that it is not always easy to confirm if the catheter is at the appropriate location only on DSA, when a definite neovasculature is absent. CT images have a better contrast
resolution and provide cross-sectional information. Also, CT during selective arteriography can more clearly depict hypervasculature of hepatocellular carcinomas and evaluate the correlation with lesions and distribution of the injected contrast material three dimensionally. Although the entire tumor seems enhanced on DSA, CT during selective arteriography sometimes reveals a small area in which the con-
Ishijima et a1
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Volume 10 Number 6
Figure 3. (continued) (e) Selective angiogram from the more proximal location of the same branch. Other subsegmental branches are depicted (arrows). A small branch produces another focal enhancement resembling a lesion (arrowhead). (f)CT during selective arteriography from the same catheter location as in e. It confirms that the lesion (arrow) is included in the distribution of the contrast material.
trast material is not infused. Therefore, we think CT during selective arteriography provides complementary information to the angiographic findings. CTAP and CTHA are the most reliable imaging methods for the detection and diagnosis of malignant hepatic lesions (6-8). Although DSA cannot depict clear stained tumor, we sometimes find small lesions enhanced more than liver parenchyma on CTHA. As CTHA is regularly performed, detection of these lesions is increased. We perform superselective TAE for these lesions with the information obtained from CT during selective arteriography. In conclusion, the combined system of CT and angiography is useful for CT during arteriography. CT during selective arteriography provides cross-sectional information on the distribution of embolization ma-
terial from the catheter. This information is complementary to the angiographic findings and helpful for superselective TAE of hepatocellular carcinomas, especially when definite tumor neovasculature cannot be visualized on DSA. References 1. Matsui 0 , Kadoya M, Yoshikawa J , et al. Small hepatocellular carcinoma: treatment with subsegmental transcatheter arterial embolization. Radiology 1993; 188:79-83. 2. Matsuo N, Uchida H, Nishimine K, et al. Segmental transcatheter hepatic artery chemoembolization with iodized oil for hepatocellular carcinoma: antitumor effect and influence on normal tissue. JVIR 1993; 4:543549 3. Inaba Y, Arai Y, Takeuchi Y, et al. Clinical effectiveness of a newly developed interventional-CT system. [in Japanese, abstract in English] Intervent Radio1 1996; 11: 43-49. 4. Sumida M, Ohto M, Ebara M,
5.
6.
7.
8.
Kimura K, Okuda K, Hirooka N. Accuracy of angiography in the diagnosis of small hepatocellular carcinoma. AJR 1986;147:531-536. Yu JS, Kim KW, Sung KB, Lee JT, Yoo HS. Small arterial-portal venous shunts: a cause of pseudolesions at hepatic imaging. Radiology 1997; 203:737-742. Chezmar JL, Bernardino ME, Kaufman SH, et al. Combined CT arterial portography and CT hepatic angiography for evaluation of the hepatic resection candidate. Radiology 1993; 189:407-410. Soyer P, Levesque M, Elias D, et al. Preoperative assessment of resectability of hepatic metastasis from colonic carcinoma: CT portography vs sonography and dynamic CT. AJR 1992; 159:741-744. Irie T, Takeshita K, Wada Y, et al. CT evaluation of hepatic tumors: comparison of CT with arterial portography, CT with infusion hepatic arteriography, and simultaneous use of both techniques. AJR 1995; 164: 1407-1412.
Use of a Combined CT-Angiography System for Demonstration of Correlative Anatomy during Embolotherapy for Hepatocellular carcinoma1 Hideyuki Ishijima, MD Yoshinari Koyama, MD Jun Aoki, MD Tsuyoshi Kawano, MD Takahito Nakajima, MD Hiroshi Ishizaka, MD Keigo Endo, MD
Index terms: Computed tomography, treatment planning Liver neoplasms, localization Liver neoplasms, therapy
JVIR 1999; 10:811-815
From the Department of Diagnostic Radiology, Gunma University Hospital, 3-39-15, Showa-machi, Maebashi, Gunma 371-8511, Japan. Received September 30, 1998; revision requested November 2; revision received December 29; accepted January 4, 1999. Address correspondence to H.I. O SCVIR, 1999
SUPERSELECTIVE transcatheter arterial embolization (TAE) is the favored treatment for patients with a solitary or few hepatic malignant tumors because it permits the delivery of a sufficient amount of the drug and embolization material to the lesions and prevents damage to normal liver parenchyma in segments without tumors (1,2). Recent advances in arterial catheterization technique have now made possible the easy insertion of a catheter tip into the subsegmental arteries of the liver. While the catheter is in the distal branch of the hepatic artery to perform superselective TAE, the existence of tumors in the infused area should be confirmed. This is usually done with conventional angiography or digital subtraction angiography (DSA). However, we encountered difficulties during TAE in lesions hard to visualize on DSA, lesions supplied from multiple hepatic arterial branches, and lesions supplied by parasitic vessels. Recently, a new system consisting of an angiographic apparatus and computed tomography (CT) has been introduced. This system allows repeated CT images to be obtained during arteriography, without moving patients to the CT room (3). To conduct a cross-sectional evaluation of drug distribution from the catheter with CT during arteriography, we performed superselective TAE for hepatocellular carcinomas using this combined system. We present
its clinical use for superselective TAE of hepatocellular carcinoma, emphasizing the usefulness of CT in performing selective arteriography.
I ~ A T E R m SAND MJTl"l'ODS Our system consists of a CT scanner and angiographic apparatus (Somatom Plus 4 P and Multistar T.O.P.; Siemens, Erlangen, Germany) located in the same room (Fig 1).The patient table is mounted on the floor and used for each examination. Fluoroscopy and DSA are performed on the patient table at the fluoroscope/DSA position with the ceiling-mounted angiographic gantry (Fig la). During the CT examination, the patient table slides to the CT position into the floor-mounted CT gantry (Fig lb). Because the patient does not have to move, it takes 1 minute to change the configuration of the system. We performed 50 embolotherapy procedures for hepatocellular carcinomas using this system between April 1998 and October 1998. DSA and TAE were performed from a femoral approach. Diagnostic arteriography, including the celiac trunk (or common hepatic artery) and the superior mesenteric artery for portography, was performed with nonionic contrast medium (Iomeprol [Iomeron 3501; Eisai, Tokyo, Japan) through a 5-F catheter in all patients. Additionally, CT during arterial portography (CTAP)
812
Combined CTIAngiography System for Demonstration of Correlative Anatomy
June 1999 JVIR
a.
b.
Figure 1. The combined system of a CT scanner (Somatom Plus 4/P) and angiographic apparatus (Multistar T.O.P.).A floor-
mounted patient table is compatible for fluoroscope/DSA and CT scan. The ceiling-mounted, C-arm angiographic gantry and floor-mounted CT gantry are included. (a) Configuration for DSA and fluoroscopy. (b) Configuration for CT scan. The patient table slides to the CT position in the CT gantry.
via the superior mesenteric artery and CT during hepatic arteriography (CTHA) via the proper hepatic artery were performed regularly. In some cases, CTHA was performed separately from the right and left hepatic artery because of the variation of the arterial branch. The CTAP and CTHA were performed using volume spiral scan technique covering the whole liver, with 5-mm beam collimation a t 120 kV and 240 mA, 5 m d s e c caudocephalic table movement, and image reconstruction every 5 mm. The contrast medium for CTAP and CTHA was diluted with saline to contain 175 mg IImL and it was infused throughout scanning a t a rate of 2 mLIsec. The scan start delay after contrast material injection was 25 seconds for CTAP, and 7 seconds for CTHA. We directed the patients to hold their breath during CT scanning. It took approximately 7-8 minutes for a single CT examination (CTAP or CTHA) including time to change the system configuration. In the 50 procedures in which TAE was used, 23 cases were determined to be a solitary lesion or few lesions in the same segment by means of diagnostic angiography, CTAP, and CTHA. These lesions were enhanced on CTHA. In these
cases, we advanced the catheter into distal branches, which were expected to be the feeding branches. A 3-F SP catheter (Terumo, Tokyo, Japan) or Microferret (Cook, Bloomington, IN) was used to perform selective catheterization in most cases. After performing a test injection of contrast material into DSA, CT during selective arteriography from the inserted catheter was performed by manually injecting 5-10 mL of the contrast medium (350 mg IImL) throughout scanning. CT during arteriography examined the entire liver using volume spiral scanning in which the scan parameters were the same for CTAP and CTHA (the parameters of the first 12 cases were 10-mm beam collimation a t 120 kV and 220 mA, 10 mmlsec caudocephalic table movement, and image reconstruction every 10 mm). TAE was performed by using a mixture of iodized oil (Lipiodol; Andre Guerbet, Aulnay-sous-Bois, France) and epirubicin hydrochloride (Farmorubicin; Kyowa-Hakko, Tokyo, Japan), followed by gelatin sponge particles (Gelfoam; Upjohn, Kalamazoo, MI). The doses of these materials were determined according to the size and number of the lesions and patients' liver function.
1 RESULTS CT during selective arteriography allowed accurate evaluation of the correlation with the lesions and distribution of the injected contrast material in all 23 cases. In 17 of the 23 cases, we could determine that the lesions were included in the contrast material distribution on CT during selective arteriography and immediately performed superselective TAE (Fig 2). In three of the 17 cases, a part of lesion was not enhanced, and we added embolotherapy from the other feeding branches. We encountered a case of complete obstruction of the right hepatic artery due to previous TAE, and performed CT during selective arteriography from the right inferior phrenic artery and confirmed the enhancement of the intrahepatic lesion. In six of the 23 cases, the tumors were not included in the distribution of the contrast material on CT during selective arteriography (Fig 3). We changed the location of the catheter more proximally or selectively inserted the catheter in other branches and repeated CT during selective arteriography. In these six cases, we used CT during selective
Ishijima et a1
813
Volume 10 Number 6
Figure 2. A 61-year-old man with a solitary hepatocellular carcinoma in segment VII of the right hepatic lobe. (a) Celiac angiogram shows a n inhomogenous contrast enhancement in the subphrenic area (arrow). However, it is difficult to detect tumor neovasculature and recognize the boundary of the lesion. (b)CT during right hepatic arteriography shows a n enhanced lesion in segment VII (arrow). ( c ) Selective angiogram of the branch of the segment VII. I t shows a faint focal enhancement. However, it is difficult to differentiate stained tumor from the summation of hepatic parenchymal stain. (d) CT during selective arteriography from the same catheter location as in c . It confirms that the lesion is strongly enhanced (arrowhead) and included in the distribution of the contrast material. Adjacent liver tissue and a part of the anterior segment are also strongly enhanced from the same branch.
arteriography two or three times in the procedure. In four of the six cases, we could confirm the feeding artery and performed superselective TAE. In two cases, however, we could not insert the catheter into the appropriate branches and performed TAE from
the proximal portion of the lobar artery.
DISCUSSION When the catheter is inserted into the distal branches to perform superselective TAE, it is necessary
to confirm if the hypervascular tumors are present in the embolization area and whether the tumors are fully covered within the embolization area. In hepatocellular carcinomas smaller than 2 cm in diameter, tumor stain is often the only indica-
814
Combined CTIAngiography System for Demonstration of Correlative Anatomy
June 1999 JVIR
Figure 3. An 83-year-old woman with a recurrent hepatocellular carcinoma in segment VIII of the right hepatic lobe. (a) CTAP shows a perfusion defect (arrow) in segment VIII. Some small cysts are noted. (b) Replaced right hepatic angiogram shows a focal contrast material enhancement in the liver just beneath the right hemidiaphragm (arrow). Dense deposition of the iodized oil is seen in the lesion previously treated with TAE from the left hepatic artery (arrowhead). ( c ) Selective angiogram of the subsegmental branch of segment VIII shows a similar focal enhancement in the same place (arrow). (d) CT during selective arteriography from the same catheter location as in c. The lesion (arrow) detected with CTAP is not included in the distribution of the contrast material (Fig 3 continues).
tion (4). However, we occasionally encountered cases in which the tumor stain became invisible a t DSA after the catheter was inserted into the distal branch. We believe that the contrast between the lesions and adjacent liver parenchyma decreased because the adjacent liver parenchyma is also enhanced as strongly as the lesions. In addition, the structural distortion in the surrounding cirrhotic liver produces
various hemodynamic changes and makes an inhomogeneous hepatogram a t angiography (4,5).As a result, it is difficult to detect small hypervascular tumors and recognize the boundary of the tumor clearly on DSA. Therefore, we think that it is not always easy to confirm if the catheter is at the appropriate location only on DSA, when a definite neovasculature is absent. CT images have a better contrast
resolution and provide cross-sectional information. Also, CT during selective arteriography can more clearly depict hypervasculature of hepatocellular carcinomas and evaluate the correlation with lesions and distribution of the injected contrast material three dimensionally. Although the entire tumor seems enhanced on DSA, CT during selective arteriography sometimes reveals a small area in which the con-
Ishijima et a1
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Volume 10 Number 6
Figure 3. (continued) (e) Selective angiogram from the more proximal location of the same branch. Other subsegmental branches are depicted (arrows). A small branch produces another focal enhancement resembling a lesion (arrowhead). (f)CT during selective arteriography from the same catheter location as in e. It confirms that the lesion (arrow) is included in the distribution of the contrast material.
trast material is not infused. Therefore, we think CT during selective arteriography provides complementary information to the angiographic findings. CTAP and CTHA are the most reliable imaging methods for the detection and diagnosis of malignant hepatic lesions (6-8). Although DSA cannot depict clear stained tumor, we sometimes find small lesions enhanced more than liver parenchyma on CTHA. As CTHA is regularly performed, detection of these lesions is increased. We perform superselective TAE for these lesions with the information obtained from CT during selective arteriography. In conclusion, the combined system of CT and angiography is useful for CT during arteriography. CT during selective arteriography provides cross-sectional information on the distribution of embolization ma-
terial from the catheter. This information is complementary to the angiographic findings and helpful for superselective TAE of hepatocellular carcinomas, especially when definite tumor neovasculature cannot be visualized on DSA. References 1. Matsui 0 , Kadoya M, Yoshikawa J , et al. Small hepatocellular carcinoma: treatment with subsegmental transcatheter arterial embolization. Radiology 1993; 188:79-83. 2. Matsuo N, Uchida H, Nishimine K, et al. Segmental transcatheter hepatic artery chemoembolization with iodized oil for hepatocellular carcinoma: antitumor effect and influence on normal tissue. JVIR 1993; 4:543549 3. Inaba Y, Arai Y, Takeuchi Y, et al. Clinical effectiveness of a newly developed interventional-CT system. [in Japanese, abstract in English] Intervent Radio1 1996; 11: 43-49. 4. Sumida M, Ohto M, Ebara M,
5.
6.
7.
8.
Kimura K, Okuda K, Hirooka N. Accuracy of angiography in the diagnosis of small hepatocellular carcinoma. AJR 1986;147:531-536. Yu JS, Kim KW, Sung KB, Lee JT, Yoo HS. Small arterial-portal venous shunts: a cause of pseudolesions at hepatic imaging. Radiology 1997; 203:737-742. Chezmar JL, Bernardino ME, Kaufman SH, et al. Combined CT arterial portography and CT hepatic angiography for evaluation of the hepatic resection candidate. Radiology 1993; 189:407-410. Soyer P, Levesque M, Elias D, et al. Preoperative assessment of resectability of hepatic metastasis from colonic carcinoma: CT portography vs sonography and dynamic CT. AJR 1992; 159:741-744. Irie T, Takeshita K, Wada Y, et al. CT evaluation of hepatic tumors: comparison of CT with arterial portography, CT with infusion hepatic arteriography, and simultaneous use of both techniques. AJR 1995; 164: 1407-1412.