Detection by CT During Arterial Portography of Colorectal Cancer Metastases to Liver Akio Yamaguchi, M.D., Tetsuya Ishida, M.D., Genichi Nishimura, M.D., Masahiro Kanno, M.D., Takeo Kosaka, M.D., Yutaka Yonemura, M.D., Ryouhei Izumi, M.D., Itsuo Miyazaki, M.D., Osamu Matsui, M.D. From the Department of Surgery II,* and Department of Radiology,~ School of Medicine, Kanazawa University, Ishikawa, Japan Yamaguchi A, Ishida T, Nishimura G, Kanno M, Kosaka T, Yonemura Y, Izumi R, Miyazaki I, Matsui I. Detection by CT during arterial portography of colorectal cancer metastases to liver. Dis Colon Rectum 1991;34:37-40.

study, w e c o m p a r e d the accuracy of CT-AP for localizing liver metastases with those of other imaging t e c h n i q u e s and f o u n d that this is a useful investigational t e c h n i q u e for trials in resecting large b o w e l cancer with liver metastases.

A prospective evaluation of the accuracy of real-time uhrasonography (US), computed tomography (CT), infusion hepatic angiography (IHA), and computed tomography during arterial portography (CT-AP) was performed on 65 resected liver metastases of colorectal cancers. The total detection rate was 58.5 percent for US, 56.3 percent for CT, 55.4 percent for IHA, and 86.2 percent for CTAP. The sensitivity of 29 lesions with diameters of smaller than 1 cm was 65.5 percent for CT-AP, CT found only two, and both US and IHA localized no more than three. The smallest lesions detectable by CT-AP were as small as 0.4 cm in diameter. CT-AP proved most useful in detecting the liver metastases, and the use of this techique is recommended for preoperative planning of hepatectomy on patients with liver metastases. [Key words: CT during arterial portography (CT-AP); Liver metastases]

MATERIAL AND METHODS T w e n t p n i n e patients with liver metastases of colorectal cancer w e r e evaluated. T h e y c o m p r i s e d 16 patients with s y n c h r o n o u s metastatic liver tum o r s and 13 with m e t a c h r o n o u s metastatic liver tumors. All of t h e m w e r e referred to us for surgical resection of metastatic tumors. T e n patients had a solitary hepatic lesion, and 19 patients multiple hepatic lesions. L o b e c t o m y was p e r f o r m e d on 10, s e g m e n t e c t o m y , on 8, and partial resection, on 11 patients. T h e d e g r e e s of liver metastases w e r e grossly classified as follows: H~ for metastases limited to o n e lobe; and H2 for f e w scattered metastatic foci in b o t h lobes. A total of 65 metastases of colorectal cancer to the liver w e r e resected. The r e s e c t e d s p e c i m e n s w e r e sliced 5 m m thick, and small metastatic foci w e r e carefully s e a r c h e d for. The final diagnosis was m a d e by m e a n s of histologic e x a m i n a t i o n of the s p e c i m e n s . The majority of patients had p r e o p e r a t i v e l y u n d e r g o n e a c o m b i n a t i o n of US, CT, IHA, and CTAP. Preoperative US was taken by use of a real-time electronic apparatus (SSD 250,280; Aloka, Tokyo), and 3.5 m H z transducers. Transverse and sagittal views w e r e o b t a i n e d b y b o t h subcostal and intercostal scanning. The CT evaluation at our institution was p e r f o r m e d with a s c a n n e r (GE 8800; General Electric Co., Milwaukee, WI), by use of 1-cm c o n t i n u o u s slices. Both pre- and postcontrast CT w e r e p e r f o r m e d in all cases. Angiographic evalua-

o n g - t e r m survival has r e c e n t l y b e e n r e p o r t e d after surgical r e m o v a l of metastatic hepatic lesions of colorectal cancers. 1-3 For i m p r o v e d prognosis, however, the p r e o p e r a t i v e evaluation of the sites of such lesions is essential. Several studies have c o m p a r e d the relative accuracies of c o m p u t e d t o m o g r a p h y (CT), u l t r a s o n o g r a p h y (US), liver scan, and infusion hepatic a n g i o g r a p h y (IHA) in detecting hepatic tumors. 4-7 The studies, however, e n c o u n t e r e d limitations to the detection of small metastatic lesions. For this reason, we have b e e n p e r f o r m i n g c o m p u t e d t o m o g r a p h y during arterial p o r t o g r a p h y (CT-AP) as a n e w diagnostic aid in detecting of u n r e c o g n i z e d liver metastases of colorectal cancer. In this

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No reprints are available. 0029/-7828/91/4306-0319/$3.00 Diseases of the Colon & Rectum Copyright 9 1991 by The American Society of Colon & Rectal Surgeons 37

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tion was performed via selective catheterization of celiac and hepatic arteries. For CT-AP, tomography was performed at 1 cm intervals. The total scanning time for the entire liver was 2.5 to 3.0 minutes. For 30 seconds before and during the scanning, 70 ml of a contrast medium (65 percent meglumine amidotrizoate) was infused via a catheter in the superior mesenteric artery at an estimated rate of 0.40.6 ml/sec during sequential scanning of the liver with 1-cm section. In CT-AP, the liver parenchyma lacking the portal blood supply is visualized as a low density area. A nodular space-occupying lesion indicating a solid tumor was diagnosed as a metastasis. But small cysts diagnosed by US or CT were excluded, and finally confirmed by intraoperative US. The preoperative imagings were compared with the surgical findings.

RESULTS Figure 1 demonstrates a liver with metastatic lesions as visualized using CT-AP. Metastatic lesions were visualized as low-density areas in CTAP. The degree of liver metastasis by gross findings was as follows: H1, 22 cases; and Hi, 7 cases. Table 1 shows sensitivities of the degree for liver metastases with various imaging methods. The diagnostic sensitivities were: 86.2 percent or IHA, 86.2 percent for US, and 89.7 percent for CT. For the three imaging techniques used together, the diagnostic accuracy was 89.7 percent, whereas that for CT-AP ran up to as high as 95.6 percent. To 65 cancer lesions identified by hepatectomy, the sensitivities of US, CT, and IHA were as low as 58.5, 56.3, and 55.4 percent, respectively, whereas CT-AP showed a sensitivity of 56/65 lesions (86.2 percent) (Table 2). The smallest diameters of metastases detectable by the four imaging techniques were: 1 cm for US, 1 cm for CT, 0.9 cm for IHA, and 0.4 cm for CTAP. Of the 65 lesions, 29 were micrometastases with diameters of smaller than 1 cm. Of the 29 micrometastases, CT-AP detected 20 (69.0 percent) preoperatively, whereas CT found only 2, and both US and IHA localized no more than 3 (Table 3). In the meantime, there were nine lesions undetectable even by CT-AP, and they were micrometastases with diameters smaller than 1 cm, with five of them measuring 0.5 cm in diameter. By site, two lesions were found in the left lobe, and seven at the right lobe. Of the four lesions with diameters of greater than 0.5 cm which were missed by

Figure 1. Metastatic liver tumors from colon cancer. A and B. CTAP showed two low density area. C. Resected specimen revealed these two lesions, 2.3 cm and 1.4 cm in the largest diameter.

Table 1 Comparison of Diagnostic Effectiveness of the Degree for Liver Metastases with Various Imaging Methods Imaging Methods

US CT IHA CT-AP * Not significant

Sensitivity* (%)

25/29 25/29 26/29 28/29

(86.2) (86.2) (89.7) (96.6)

CT DURING ARTERIAL PORTOGRAPHY FOR LIVER METASTASES

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Table 2 Diagnostic Accuracy of Lesion Detection by Various Imaging Methods Imaging Methods

US CT IHA CT-AP

Sensitivity (%)

38/65 36/64 36/65 56/65

(58.5) (56.3) (55.4) (86.2)

* *

* P < 0.01.

Table 3 Detectability of Micrometastases with Diameters Smaller than 1 cm by Various Imaging Methods Imaging Methods

Sensitivity (%)

US CT IHA CT-AP

3/29 (10.3) 2/29 (6.9) 3/29 (10.3) 20/29 (69.0)

*P

Detection by CT during arterial portography of colorectal cancer metastases to liver.

A prospective evaluation of the accuracy of real-time ultrasonography (US), computed tomography (CT), infusion hepatic angiography (IHA), and computed...
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