To evaluate the value of multislice spiral CT angiography (MSCTA) in the preoperative application of hepatocellular carcinoma intervention. Methods MSCTA and digital subtraction angiography (DSA) were performed in 62 patients with hepatocellular carcinoma before hepatic artery chemoembolization to analyze the hepatic artery anatomy, hepatocellular carcinoma feeding arteries and portal vein system. Results MSCTA was highly consistent with DSA in showing the abdominal artery and hepatic artery anatomy.
The maximum intensity projection (MIP) and DSA were both better than volume rendering (VR) for tumor-feeding arteries (P<0.05); MIP was better than VR for grade 3 hepatic arteries (P<0.05), and there was no difference with DSA; MIP was better than VR for grade 4 and above hepatic arteries. There was no statistical difference between MSCTA and DSA for the display of portal cancer thrombus and collateral vessels (P>0.05), and DSA was superior to MSCTA for the display of hepatic artery-portal fistula (P<0.05).
Conclusion MSCTA can accurately display the blood supplying artery and portal vein system of hepatocellular carcinoma and effectively guide the interventional treatment.
Primary hepatocellular carcinoma is insidious, highly malignant, and most patients are in the middle and late stages at the first diagnosis, and only 20% of them can be surgically resected. transcatheter hepatic artery chemoembolization (TACE) is the most common treatment for unresectable hepatocellular carcinoma [1-2]. A comprehensive understanding of the anatomy and variants of the hepatic arteries, as well as the source of the tumor supplying artery and related comorbidities, can effectively guide the successful completion of interventional treatment.
In this study, multislice spiral CT angiography (MSCTA) was applied to provide the above information, which is summarized as follows.
1. Data and methods
1.1 General data Sixty-two patients with primary liver cancer who underwent interventional treatment in our hospital from September 2009 to October 2011 were collected, and all of them met the diagnostic criteria of the Ministry of Health’s “Diagnostic Code for Primary Liver Cancer (2011 version)” [3]. There were 50 male cases and 12 female cases, aged 26-81 years, with an average age of (53.9±13.2) years. There were 38 cases of giant hepatocellular carcinoma, 14 cases of diffuse hepatocellular carcinoma and 10 cases of multiple nodular hepatocellular carcinoma; 25 cases had portal vein thrombosis, 19 cases had hepatic artery-portal vein fistula and 3 cases had hepatic artery-hepatic vein fistula. All patients underwent MSCTA examination within 1 week before the intervention.
1.2 MSCTA scanning method and reconstruction technique A GE Lightspeed 64-row VCT scanner was used, and patients were scanned in the cephalopod direction, ranging from the apex of the liver to the lower pole of the kidney. Scanning parameters: voltage 120 kV, current 250 mAs, collimation: 64×0.625, layer thickness 5 mm, pitch 1.375:1, rotation time 0.5 s. Enhancement scans were performed using a high-pressure syringe with dough injection of nonionic contrast agent iohexol (300 mgI/mL, 1.5 mL/kg, total 80-120 mL) at an injection rate of 3.5 mL/s.
The arterial phase delay time was determined using the contrast trigger technique, with the center of the abdominal aorta at the thoracic 11 vertebral level as the area of interest, and the trigger point threshold was set at 100 Hu/6 s. The average arterial phase scan delay time was 24 s; the portal phase scan started 12 s after the end of the arterial phase scan, and the average scan delay time was 45 s; the parenchymal phase scan started 11 s after the end of the portal phase scan, and the average scan The delay time was 65 s on average.
The original data from the arterial, portal and parenchymal phases were reconstructed with a layer thickness of 0.625 mm and an interval of 0.625 mm in the axial position, and the reconstructed images were transferred to the AW 4.3 workstation for post-processing. The 3D imaging methods included maximum intensity projection (MIP), volume rendering (VR), multi-planar reformation (MPR), etc.
1.3 Abdominal arteriography and TACE treatment Using Siemens Angiostar plus or GE Innova 3100 DSA machine, the femoral artery was punctured by the Seldinger method, the RH catheter was inserted into the abdominal artery, and 30 mL of contrast agent iohexol (300 mgI/mL) was injected at a rate of 8 mL/s with a high-pressure syringe, and digital subtraction angiography ( Digital subtraction angiography (DSA) was performed at a frame rate of 2 frames/s, and the patient was exposed for 20 s under a strict breath-holding state, and after image acquisition, the tumor development in the hepatic artery and parenchymal stages was repeatedly and dynamically observed.
imaging, with an injection rate of 15 mL/s and a total volume of 30 mL, in order to detect the variant blood supply, combined with preoperative MSCTA for hepatocellular carcinoma variant or collateral blood supply arteries after super-selective cannulation for TACE treatment.
1.4 Observation indexes Comparative analysis of two types of vascular images, MSCTA and DSA, was performed by two imaging senior attending physicians; the right and left branches of the hepatic artery and the left and right trunks of the portal vein were considered as grade 1, their branches were considered as grade 2, and the hepatic artery with grade 4 branches and above were considered as grade 4.
Main observations.
①The origin, course and variation of the abdominal artery and hepatic artery vasculature;
②Lateral branch blood supply of hepatocellular carcinoma;
(③) Portal vein cancer thrombosis and arteriovenous fistula.
1.5 Statistical treatment The data were statistically analyzed by SPSS13.0 statistical software, and χ2 test was performed for each evaluation index, and P<0.05 indicated that the difference was statistically significant.
2, Results
2.1 Display of abdominal artery and hepatic artery anatomy MSCTA can clearly display the anatomy of abdominal artery and hepatic artery in the whole group of 62 patients with hepatocellular carcinoma, which is highly consistent with DSA, and better guides the judgment of arterial blood supply source of hepatocellular carcinoma and super-selective cannulation before TACE. It showed regular celiac artery-common hepatic artery blood supply in 54 cases; 4 cases of upward travel of celiac artery opening, 15 cases of redundancy and distortion; 2 cases of occlusion of celiac trunk, both of which were communicated with the hepatic innominate artery by superior mesenteric artery via pancreaticoduodenal artery arch;
The anatomical variation of hepatic artery was found in 8 cases, including 1 case of ectopic origin of common hepatic artery from superior mesenteric artery, 6 cases of variation of right hepatic artery or right parahepatic artery from superior mesenteric artery; 13 cases of hepatocellular carcinoma were found to have parasitic blood supply artery, including 12 cases of origin from right subphrenic artery, 4 cases of gastroduodenal artery and 1 case of right intercostal artery.
2.2 Display of hepatic arteries and tumor-supplying arteries In the display of tumor-supplying arteries, MIP and DSA were roughly similar, with no statistical difference between them, and both were better than VR (P<0.05); the display of the branches of grade 1 and 2 hepatic arteries was 100% for both MIP and DSA, and there was no difference between the three compared with VR (P>0.05); the display of grade 3 hepatic arteries showed MIP and DSA The difference was statistically significant (P<0.05); for grade 4 and above hepatic artery branches, MIP was superior to VR, and DSA was superior to MIP.
2.3 Display of portal vein and its comorbidities MSCTA showed 25 cases of portal vein trunk or branch carcinoma, 3 cases of portal vein cavernous degeneration, 8 cases of esophagogastric fundic varices, 9 cases of hepatic artery-portal vein fistula, and 1 case of hepatic artery-hepatic vein fistula. portal vein fistula was better than MSCTA (P<0.05), and MSCTA showed poorly in peripheral low-flow hepatic artery-portal vein fistula.
3. Discussion
DSA has always been considered as the “gold standard” for showing vascular lesions. With the rapid development of medical imaging equipment and technology, MSCTA technology provides a new way to display vascular images non-invasively, and is increasingly used in clinical practice, replacing DSA as the “gold standard” in aortic and pulmonary artery imaging.
Hepatic artery anatomical variants are common and complex, and the arterial blood supply for hepatocellular carcinoma, especially after multiple interventions, is not only from the variant hepatic artery but also from the parasitic lateral hepatic branch supply artery. In the process of interventional treatment, some of the hepatocellular carcinoma blood supply arteries are often missed or never found, and finding these abnormal blood supply vessels is the key to the success of TACE. Our data show that MSCTA can provide clear three-dimensional reconstructed images that clearly show the anatomy and variation of the abdominal and hepatic arteries in patients with hepatocellular carcinoma, which are highly consistent with DSA.
In the post-processing technique MIP and DSA showed 100% of grade 1 and 2 hepatic artery branches, and there was no difference between the three compared with VR. For grade 3 hepatic artery, MIP showed similar to DSA and better than VR, but VR could better show the three-dimensional relationship between tumor and blood vessels, especially when there were anatomical variants and collateral blood supply; DSA showed grade 4 and above hepatic artery branches significantly The DSA shows the branches of grade 4 and above hepatic arteries significantly better than MIP and VR, but some small vascular branches are not clearly shown due to too much overlapping of orthotopic vessels;
MIP can show the tumor-feeding arteries similarly to DSA and better than VR, but in patients with severe cirrhosis and recurrence after surgical resection, MIP and VR cannot effectively show the tumor-feeding arteries because of the slimness of the hepatic arteries and their intrahepatic branches. It can help to select a more suitable catheter for the variant hepatic artery, better guide the super-selective cannulation of the tumor-feeding artery, and reduce intraoperative X-ray exposure time for the physician and the patient.
Patients with inoperable hepatocellular carcinoma often have combined portal vein thrombosis, hepatic artery-portal vein fistula, and hepatic artery-hepatic vein fistula. When choosing whether to embolize and the degree of embolization, it is necessary to consider whether the portal vein thrombus is located in the trunk or in a branch, and whether there is adequate portal vein collateral supply when it is located in the trunk. Our data show that MSCTA can detect portal vein cancer emboli on routine scans, and there is no statistical difference in the display of portal vein cancer emboli and portal vein collateral vessels compared with DSA.
Spiral CT portal venography (CTPV) can visualize the portal venous system and collateral circulation, and coronal MIP shows the anatomical structure of portal vein most clearly. This provides a lot of information for accurate localization of intrahepatic lesions and interventional treatment by portal vein.
Arteriovenous fistulae can accelerate intrahepatic dissemination and extrahepatic metastasis of hepatocellular carcinoma, and blind embolization in the presence of hepatic arteriovenous fistulae can lead to pulmonary embolism, and the presence of concomitant hepatic arteriovenous fistulae will directly affect the choice of treatment and patient prognosis. The clear visualization of the main trunk and branches of the portal vein by MSCTA can provide clear guidance for the percutaneous puncture route during trans-portal interventions.
In conclusion, MSCTA of the abdominal artery before TACE for hepatocellular carcinoma can provide a detailed understanding of the anatomy and variation of the hepatic artery, the presence of tumor variation and collateral blood supply, and the presence of comorbidities in the portal vein system.