I. Vascular interventional radiology
Also known as interventional angiography, it refers to the injection of drugs or certain substances into the lumen of a vessel from a catheter or the administration of certain measures for therapeutic purposes at the same time as diagnostic angiography. There are three kinds of commonly used vascular interventional techniques.
1.Intravascular infusion drug therapy
(1) Vasoconstriction therapy is performed by drip injection of pressin into the relevant artery through catheter to control gastrointestinal bleeding, such as bleeding from esophagogastric varices, diffuse bleeding from gastric mucosa and bleeding from colonic diverticulum, etc.
(2) Tumor chemotherapy catheter is left in the artery supplying the tumor to drip chemotherapy drugs to increase the local drug concentration and avoid or reduce the systemic reactions caused by chemotherapy.
2.Transcatheter vascular embolization method
One is to treat internal bleeding such as traumatic organ bleeding, ulcer disease, tumor or unexplained organ bleeding. Embolization is also used to treat tumors, as the tumor circulation is partially or completely blocked by the embolic material to control the growth of the tumor or as a treatment for surgical resection; it can also be used for non-surgical organ removal, such as injection of embolic material into the branches of the splenic artery, i.e., partial splenic embolization, to treat hypersplenism without affecting the immune function of the spleen.
Commonly used embolic substances such as autologous blood clot, gelatin sponge, anhydrous alcohol, polyvinyl alcohol, liquid silicone, stainless steel ring, metal or plastic spheres, and Chinese herbal medicine Bletus.
3.Percutaneous endoluminal angioplasty
In the 1960s, it was applied to arteries to dilate narrowed vessels, and after the successful development of double-lumen balloon catheter in the 1970s, it was widely used, mostly for iliac, femoral and N arteries and renal arteries. PTA (or PTPA) for renal arteries is mostly used for nephrogenic hypertension to dilate narrowed renal arteries, thus lowering blood pressure. The catheter used for PTA is a double-lumen catheter with a capsule, and the capsule is placed at the stenotic vessel, and the capsule is filled with a fluid containing a contrast agent and pressurized to 3-6 atmospheres for 10-15o each time.
PTA is mostly used in vessels with atherosclerotic stenosis. The mechanism is that the atheromatous plaque is compressed and the intima and mesoderm are torn and stretched, widening the lumen. Other causes of stenosis, such as multiple aortitis and congenital stenosis, can sometimes be treated with PTA.
II. Non-vascular interventional radiology
1.Percutaneous puncture biopsy
A fine needle (22-23 gauge, 0.6-0.7 mm outside diameter) is used to directly puncture the lesion area in various parts of the body percutaneously, which facilitates the removal of the lesion biopsy specimen due to the special device of the needle. A fine needle can also be used to directly aspirate the lesioned tissue fragments and then biopsy them.
Chest PNB is used to diagnose lung, mediastinal and chest wall lesions, and is important for the qualitative diagnosis of intrapulmonary spherical disease o and mediastinal masses, with an accuracy rate of up to 85%. The more common complications are pneumothorax and bleeding, but there are few complications with fine needles. Abdominal PNB is used more often for liver, bile, pancreas, spleen, kidney and posterior abdominal wall masses, and the diagnostic readiness is also high; bone puncture requires a thicker bone puncture needle, which can diagnose bone tumors. In addition, it is also used to puncture thyroid masses, intraorbital masses, etc.
In order to ensure that the needle safely reaches the lesion to be investigated, a TV screen, CT, B-ultrasound, and related imaging must be used to guide the direction of puncture.
2.Percutaneous puncture and drainage
(1) Percutaneous hepatic percutaneous choledochusdrainage (Percutaneoustranshepaticcholedochusdrainage, PTCD or PTD) is performed due to malignant (e.g., cholangiocarcinoma, pancreatic head cancer) or benign (e.g., common bile duct stones) lesions, which cause extrahepatic biliary obstruction and clinical jaundice. PTCD can relieve obstruction, reduce jaundice, and provide favorable conditions for radical surgery. Before performing PTCD, a percutaneous hepatic cholangiogram (Percutaneoustranshepatic) is performed to determine the site, degree, extent and nature of biliary obstruction. If the catheter passes through the obstructed area and is left in the bile duct distal to the obstruction or enters the duodenum, bile flows into the bile duct below the obstruction or the duodenum along the lateral holes of the catheter, which is the internal drainage.
(2) Percutaneous nephrostomy (Percutaneoustransrenalpyelotomy) is mainly used for drainage of urinary tract obstruction, and the catheter of the fistula can also be used to push down the stone in the renal pelvis or ureter and send it to the bladder for discharge. A percutaneous antigradepyelography is performed to observe the morphology of the urinary tract, the site of stricture or obstruction, and the extent of the obstruction.
Classification by clinical application
1. Vascular disease.
(1) PTA+Stent for vascular stenosis.
(2) Thrombolysis + PTA and/or Stent for the treatment of vascular stenosis.
(3) Application of embolic material, steel ring, endoprosthesis for aneurysm, AVM, arteriovenous fistula, vascular bleeding.
(4) Application of puncture + PTA + Stent for the treatment of portal hypertension, Buga’s syndrome.
(5) Application of embolization or vasopressin for gastrointestinal vascular bleeding.
(6) Inferior vena cava filter to prevent thrombus dislodgement in the lower extremities and abdominopelvic region.
2.Heart disease.
(1) Application of closed umbrella to treat ASD and VSD.
(2) Application of steel ring or viscosupplementation for PDA.
(3) Application of balloon dilation for pulmonary valve and mitral valve stenosis.
(4) Application of PTA+Stent for the treatment of coronary stenosis.
(5) Radiofrequency ablation for tachycardia.
(6) Pacemaker treatment of various bradycardia.
3.Tumor.
(1) Selective tumor supply artery perfusion chemotherapy + embolization for malignant tumors.
(2) Percutaneous puncture injection of anhydrous alcohol and boiling water for the treatment of malignant tumors.
(3) Application of embolization to treat cavernous hemangioma, trapezoid hemangioma, uterine leiomyoma, osteosarcoma, nasopharyngeal fibrovascular tumor, etc.
(4) Thermal ablation for hepatocellular carcinoma and lung cancer.
4.Non-vascular diseases.
(1) Application of PTA + Stent or simple PTA for the treatment of gastrointestinal tract, urinary tract, biliary tract, airway, nasolacrimal duct stenosis.
(2) Application of embolization or transtubal injection of sclerosing agent for ectopic pregnancy.
(3) Application of dilation for ureteral stenosis.
5.Puncture biopsy.
Special puncture needles are applied to aspirate or take tissue for pathological examination.