What Is a Digital Subtraction Angiography?

The basic principle of DSA is to digitally input two X-ray images taken before and after injection of contrast medium into an image computer, and obtain clear pure blood vessel images through subtraction, enhancement and re-imaging processes, and simultaneously display blood vessel shadows in real time. DSA has the advantages of high contrast resolution, short examination time, small amount of contrast agent, low concentration, significantly reduced X-ray absorption of patients, and saving film. It is of great significance in the clinical diagnosis of vascular diseases.

Basic Information

Chinese name

Digital subtraction angiography

Foreign name

DSA

Auxiliary tools

electronic calculator

Application

clinical

Preparing for digital subtraction angiography

1. Explain the purpose of imaging and possible complications and accidents to patients and their families, and sign an imaging agreement;

2. Explain the process and precautions of the angiography to the patient in order to eliminate concerns and strive for intraoperative cooperation;

3. Check heart, liver and kidney function, blood routine and clotting time;

4. Necessary imaging studies, such as B-ultrasound, CT, etc.

5. Iodine and narcotics should be processed as required by the Pharmacopoeia;

6. Do not eat or drink for 4 hours before surgery, empty urine, and train patients to hold their breath;

7. Routine skin preparation at the puncture site and sedation if necessary;

8. Establish a venous channel to facilitate intraoperative medication and rescue.

Clinical significance of digital subtraction angiography

1. Application of Interventional Radiology

In interventional radiology, DSA's guide tube method can be used to display the advancement of a catheter or guide wire in a blood vessel in real time, and clearly observe the relationship between the catheter and the guide wire. Selective or superselective intubation. It is also helpful for various interventional procedures, such as embolization of bleeding lesions and deformed blood vessels, embolization of tumor blood vessels or local injection of chemicals, and intraluminal angioplasty of narrow vessels using a balloon catheter.

2. Examination of cerebrovascular disease

Especially for qualitative localization diagnosis of aneurysms and arteriovenous malformations, it is the best diagnostic method. Not only can it provide the exact location of the lesion, but also the scope and severity of the lesion can be clearly understood, providing a more reliable objective basis for surgery. In addition, it is also of high diagnostic value for ischemic cerebrovascular disease. DSA can clearly show the arterial lumen stenosis, occlusion, and the establishment of collateral circulation. For cerebral hemorrhage and subarachnoid hemorrhage, the cause of bleeding can be further investigated, such as aneurysms, vascular malformations, and cavernous hemangioma .

3. Examination of the thoracic vascular system

DSA is quite satisfied with the display of the heart and large blood vessels, and can clearly show the aortic arch, ascending aorta, and descending aorta; it has a good diagnostic value for aortic dissection aneurysms, and it can show the lesion range well for aortic inflammation and can clearly Pulmonary artery is shown; diagnosis of aortic stenosis and aortic aneurysm shape is also of great value.

4. Examination of the abdominal vascular system

The abdominal aorta and its main branches such as the renal arteries, celiac arteries and their branches, the superior mesenteric and inferior mesenteric arteries can all be well displayed in DSA examination. In the presence of abdominal arterial stenosis, especially severe atherosclerotic stenosis, arterial intubation becomes difficult. At this time, the use of DSA can show its superiority. At present, the most widely used DSA examination of abdominal vessels is hepatic and renal arteriography.

5. Examination of the vascular system of the limbs

DSA can diagnose stenosis and occlusion of the limb arteries and their trunk branches, but it is difficult to show the fine branches and collateral circulation of the brachial artery. Can also be used to show aneurysms and arterial deformities.