To evaluate the efficacy of transcatheter hepatic artery embolization in the treatment of hepatic cavernous hemangioma. Methods: Twenty-eight cases (34 times) of hepatic cavernous hemangioma were treated by transcatheter injection of iodine oil and pinyamycin emulsion, followed by appropriate amount of gelatin sponge granules to enhance embolization. All the patients’ clinical symptoms disappeared completely after 1 to 3 embolization treatments, and the tumor had different degrees of shrinkage. 19 cases (67.9%, 19/28) were in partial remission (tumor shrinkage greater than 50%), and 7 cases (25%, 7/28) were in improvement (tumor shrinkage 25% to 50%). Conclusion Combined embolization with iodine oil and pinyamycin emulsion plus appropriate amount of gelatin sponge granules is an ideal method for treating hepatic cavernous hemangioma and has been clinically observed to be safe and effective. Hepatic hemangioma is the most common benign tumor of the liver, with an incidence of 0.4%-20%. 85% of patients have no clinical symptoms, and most of them are found incidentally during imaging examinations. There are four types of hemangioma: Cavernous hemangioma of liver (CHL), sclerosing hemangioma, hemangioendothelioma and capillary hemangioma, among which CHL is the most common (the incidence of autopsy is 0.4%-7.4%). The most dangerous complication is hemangioma rupture and bleeding, therefore, aggressive treatment should be provided to control the development of large CHL. Traditional surgical resection is more invasive and has a relatively high chance of complications, with an operative mortality rate of 1-4%. Transcatheter hepatic artery embolization has become one of the major minimally invasive therapies for CHL because of its low trauma, high success rate, low complications, and reliable medium- and long-term efficacy. I. Clinical data Since May 2000, our department has treated 28 patients with hepatic cavernous hemangioma, 13 males and 15 females, aged 26-63 years, with an average age of 44.5 years. The diameter of CHL ranged from 3 to 20 cm, of which 19 were single and 9 were multiple; 4 were in the left liver, 10 in the right liver, and 14 were involved in both the left and right lobes of the liver. All cases were clearly diagnosed by color Doppler ultrasound, CT or MRI, and the clinical manifestations were mostly different degrees of epigastric distension and discomfort. Transcatheter embolization After successful femoral artery puncture with a modified Seldinger technique, a 5FRH catheter was used for abdominal artery-common hepatic artery angiography with a Siemens Angiostar plus or GE Innova 3100 digital subtraction angiography machine. After the site, size, number and blood supply artery of CHL were clearly defined, the catheter was inserted super-selectively into the blood supply artery, and Pingyangmycin (PYM) 8-32 mg, dissolved in 5~10 ml of contrast oil emulsion (PYM) was injected slowly according to the size of the lesion and blood supply. Pingyangmycin (PYM) 8～32 mg, dissolved in 5～10 ml of contrast agent (Onepac 300 g/L), added into 10～20 ml of iodized oil to make emulsion], and then embolized the main trunk of the blood supply artery with appropriate amount of gelatin sponge particles (2 mm × 2 mm × 2 mm). If only partial staining of CHL or extensive intrahepatic multiplicity was found, superior mesenteric artery and inferior phrenic artery were sequentially performed, and when variant blood supply was found, super-selective embolization of the corresponding blood supply vessels was performed respectively. If necessary, a coaxial microcatheter was used, and the embolization was repeated after embolization to confirm successful embolization. For CHL with a diameter greater than 15 cm, embolization was performed in stages to reduce the post-embolization reaction. In this group, 23 cases were embolized once, 4 cases were embolized twice, and 1 case was embolized three times, and the interval between interventions was about 1-10 months. Follow-up and efficacy evaluation Generally, the liver CT or color Doppler ultrasound was reviewed 1, 3, 6 and 12 months after embolization to observe the size of tumor, blood flow and iodine oil deposition, as well as liver function and blood routine to understand the degree of remission of clinical symptoms. The maximum follow-up period was 24 months. According to the WHO objective efficacy assessment criteria for solid tumors, the efficacy was classified as partial remission (tumor diameter multiplied by more than 50%), improvement (tumor diameter multiplied by 25% to 50%), and stability (tumor diameter multiplied by less than 25%) according to the product of the largest diameter and the largest pendant diameter after embolization treatment. The DSA signs were: no or mild thickening of the blood supplying artery, displacement of the hepatic artery and its branches by pushing pressure, and a “ball in hand” sign. In the early stage of artery, abnormal sinusoidal filling can be seen, which is characterized by dotted or lumpy staining, and many vascular lakes can be seen in the tumor. In the portal vein stage, the tumor staining was still seen from the periphery to the center, and it showed “early exit and late return”. Two cases of hepatic artery-portal vein fistula showed early portal vein branching and delayed emptying. II. Postoperative complications All cases had different degrees of post-embolization syndrome, mainly manifested as: mild to moderate distension in the liver area of different degrees about 1 week after surgery, nausea, vomiting, transient hypothermia, and some patients complained of shoulder and back pain, which disappeared after active symptomatic supportive treatment. The 12 cases in this group had mild abnormalities of liver function, all of which occurred in those with large tumors and multiple foci, mainly transient mild elevation of transaminases, and all of them returned to normal after active postoperative intensive hepatoprotective treatment. No other serious complications occurred. The clinical symptoms completely disappeared after one to three embolization treatments in all cases. The tumor was significantly smaller than that before surgery in all cases from 1 to 12 months after surgery, and the iodine oil was well deposited. There were 19 cases of partial remission (67.9%, 19/28), 7 cases of improvement (25%, 7/28), 2 cases of stabilization (7.1%, 2/28), and the number of multiple lesions decreased. Ultrasound showed good iodine oil deposition in the lesions, which was prominent in the periphery, and the blood flow signal around the tumor disappeared. No enlargement of the tumor or new lesions were observed in all cases at 12 to 24 months of follow-up. The incidence of hepatic hemangioma can occur at any age, with a male to female incidence of 1:2 to 1:5[4] . Most of them are slow growing, with mild or no symptoms, and have a good prognosis. Therefore, the treatment of hepatic hemangiomas has been controversial. Surgery is indicated when there is hemorrhage, rupture, thrombosis, increase in size, or severe abdominal pain and discomfort[5] . We advocate aggressive treatment to control the progression of CHL if the tumor is more than 5 cm in diameter or located under the hepatic envelope. Transcatheter hepatic artery interventional embolization for CHL is currently recognized as a simple and effective minimally invasive treatment. Studies have demonstrated that CHL tumors are exclusively supplied by the hepatic artery and are histologically similar to microarteries, being vascular malformations originating from the terminal microarteries of the hepatic artery and unrelated to the portal vein. There were no normal hepatocytes or hepatic sinusoidal structures in the tumor, and there was no dual blood supply tissue structure. The malformed sinusoids were connected between the hepatic artery, portal vein and hepatic vein, and some cases were accompanied by arteriovenous fistula. In a few cases of CHL with significant low flow, the portal vein may become the main blood vessel. The imaging diagnosis of CHL is closely related to its pathological histology. Ultrasound shows signs of tumor margin dehiscence, vascular entry or vascular penetration. Because of the slow blood flow of sinus in the tumor, the CT scan shows the characteristic of “early exit and late return”, and the T2WI shows the “light bulb sign” with the prolongation of echo time. DSA can further clarify the diagnosis and clearly show the location, number, size and distribution of CHL. The DSA showed no or mild thickening of the blood supplying artery, pushing and shifting of the hepatic artery and its branches, showing the “hand holding the ball sign”; in the early stage of the artery, abnormal filling of the blood sinuses around the lesion was seen, and many vascular lakes were visible in the tumor, showing the typical “branch hanging fruit sign”; in the portal vein stage. In the portal vein stage, the contrast agent gradually spreads from the periphery to the center, and the tumor staining is still seen, showing the “early exit and late return” performance. It can also clearly show the blood supply vessels of the tumor and the presence of hepatic artery-portal vein fistula. Since the blood supply of CHL mainly comes from the hepatic artery, the sinusoidal cavity is full of blood cells and mechanized thrombus, there is no neural regulation, and the tumor lacks reticuloendothelial system and lymphatic system, which is slow to clear the material entering through the blood vessels. At present, there are many different embolic agents used in interventions, including iodinated oil, sodium cod liver oil, anhydrous ethanol, pinyamycin, and many other combinations. In our hospital, we choose Pingyangmycin iodide oil emulsion supplemented with appropriate amount of gelatin sponge to enhance embolization treatment of CHL, and achieved good clinical efficacy. Pingyangmycin is a kind of vascular sclerosing agent, which breaks the DNA chain by inhibiting DNA synthesis, destroys the abnormal endothelial cells in CHL, and collapses the blood sinus. Pingyangmycin also has mild action, less irritation and anti-infection properties, and few postoperative adverse effects and complications. Iodized oil is a kind of peripheral vascular embolic agent and drug carrier, which can be injected into tumor vessels after emulsifying them into a suspension. It can produce the synergistic effects of vascular removal, peripheral embolization and slow release, which can destroy the endothelial cells of tumor vessels, cause necrosis of endothelial cells of blood sinus and thrombosis, promote fibrosis of hemangioma, prevent rupture and bleeding, and make the tumor shrink or even disappear. The gelatin sponge particles strengthen the embolization, which can prevent the flushing of blood flow and make the pinyamycin iodine oil emulsion stay in the blood vessel for a longer time. If necessary, microcatheters can be used, and the catheter head should be placed as close to the hemangioma as possible to ensure that the iodine emulsion does not flow back into the normal liver tissue. The blood supply to the bile duct comes from the hepatic artery, which branches to the bile duct and anastomoses with each other in the outer layer of the bile duct to form a peribiliary vascular cluster with the bile duct as the axis. Embolic agents can cause thrombosis of these nutrient vessels, resulting in chronic ischemia and fibrosis of the bile ducts, and extensive hepatic artery embolization can cause strong damage to the bile ducts. Reasonable control of the embolic agent is an important guarantee to prevent complications. The amount of embolic agent should be decided according to the size of CHL and the number of vascular beds in the lesion at DSA imaging. The main adverse effects of pinyamycin are pulmonary fibrosis and interstitial lung lesions, and the cumulative dose should not exceed 400 mg[11] . We control the dosage of pinyamycin to 8-32 mg under fluoroscopy, and slowly push iodine oil emulsion in small amounts, intermittently, to occlude the blood sinus without reflux. The application of lidocaine can avoid vasospasm and affect the entry of embolic agent, and also reduce the painful reaction during embolization. If the intraoperative angiogram shows sparse or absent local arterial branches in the liver, and the hemangioma is only partially stained with defective areas, the presence of a variant blood supply should be considered. In this case, DSA imaging of the abdominal artery, or additional imaging of the superior mesenteric artery, the left gastric artery and the inferior phrenic artery should be performed to find the CHL variant blood supply artery and embolize it. Four cases (14.3%) of heterogeneous tumor blood supply were seen in this group. Hepatic artery-portal fistula was present in 19-26% of cases of hepatic hemangioma. Since the fistula is usually located at the edge of the tumor, if the fistula is treated first, the CHL supply artery may be occluded and embolization cannot be performed. If the fistula is treated first, it may result in the occlusion of the CHL supply artery and prevent embolization. We found two cases of hepatic artery-portal vein shunt during the interventional procedure, so we first injected iodine oil emulsion through the catheter beyond the fistula by super-selective cannulation, and then embolized the abnormal access with gelatin sponge pellets, and achieved good results. The following cases should be considered: ①Tumor larger than 15 cm or distributed across the liver lobes; ②Age older than 60 years, combined with (or) abnormal liver function; ③Tumor with multiple blood supply, single embolization is difficult; ④Large number of multiple hemangiomas in the liver. The main blood supply artery or part of the lesion can be embolized first, and then branch interventions can be performed to reduce the occurrence of liver damage and serious complications. If the iodine defect is still visible on CT scan after embolization, repeat embolization will be decided according to the reduction of the tumor. The tumor can be significantly reduced after CHL interventional embolization, but some patients still have unsatisfactory results. We believe that the main factors affecting the efficacy are: ①The size, location and number of CHL: the smaller the hemangioma, the greater the cure rate; multiple patients are more likely to recur. In case of difficult super-selective cannulation, the dose of embolization agent is limited in order to reduce the damage to normal liver tissues, so the embolization effect is poor; ②The blood supply of CHL: the volume reduction is obvious for single hepatic artery blood supply because embolization can be more complete, but it is relatively difficult to embolize completely for multiple blood supply. ③If the CHL is revascularized or the collateral circulation is established, the lesion can be enlarged again, and then embolization should be repeated. The common reaction is post-embolization syndrome, which can be treated symptomatically. Once serious complications caused by ectopic embolism are diagnosed, surgical treatment should be performed immediately. In conclusion, transcatheter arterial embolization of CHL with pinyamycin iodide oil emulsion plus appropriate amount of gelatin sponge has short hospitalization time, easy operation, few complications, safe and effective, and can be repeatedly treated. Although the tumor could not disappear completely in some patients, the iodized oil deposit around the lesion was dense, limiting the growth rate of CHL, and the patients survived with the tumor, relieving clinical symptoms and reducing the chance of life-threatening serious complications such as CHL rupture and bleeding, which is a more ideal treatment for CHL.