Digital Substruction Angiography (DSA)
What is Digital Subtraction Angiography?
Digital Subtraction Angiography (DSA) is an interventional radiological method used to clearly visualize blood vessels in tissues. It is often used to detect a problem with blood flow in the vessels of the brain. A contrast agent is given to the body for imaging. When the contrast material reaches the desired area to be imaged through the blood vessels, X-ray images of this area are taken. The device processes that these images are used called “subtraction” technique. As a result of this procedure, the blood vessel structure of the region and the degree of blood supply are clearly revealed.
Digital subtraction angiography (DSA) is considered a “gold standard” imaging modality for detecting problems with blood flow. It is an invasive method as it requires intravenous administration of contrast material during digital subtraction angiography (DSA). There is a risk of complications from the given contrast material. However, this risk is similar to other invasive imaging methods.
What are the Benefits of Digital Subtraction Angiography?
Digital subtraction angiography, a fluoroscopic imaging technique, has been used safely since 1970s. Thanks to this technique, which reveals the blood supply in the desired region, the vascular structure and real-time blood supply of the region can be displayed as clearly as possible.
In order to provide these images, the image of the target region (mask image) is taken before the contrast agent is administered. The device thus displays the anatomy of the region and foreign bodies (stent, surgical clips, etc.) if any, like a normal X-ray image. A contrast agent is then injected. Images are taken consecutively with the injection. These images and mask images are subtracted from each other. As a result, only areas filled with contrast material appear. These areas are the vascular structures and the areas fed by the blood flowing in these veins.
The demonstration that interventional radiology achieves more successful results in time as open procedures increases the indications for such examinations. Today, Digital subtraction angiography, which is mostly used for endovascular aneurysm repair, arterial stenting, thrombectomy, arterial balloon angioplasty, endovascular embolization, is an effective technique in the treatment process as well as diagnosing diseases by the specialist.
When is Subtraction Angiography Used?
Digital subtraction angiography is used to both detect and treat blood vessel pathologies and vascularity. The successful performance of many open vascular procedures by interventional radiology also increases the use and indications of Digital Subtraction Angiography.
Digital subtraction angiography can be used to accurately evaluate arteriovenous malformations for diagnosis, intracerebral hemorrhage of unknown etiology, and aneurysms in subarachnoid hemorrhage when CTA/MR is negative.
Digital subtraction angiography can be used for treatment preoperative embolization of vascular tumors, arteriovenous fistula/malformation embolization, endovascular treatments for vasospasm as a complication of subarachnoid hemorrhage, intracranial/extracranial stent placement, mechanical thrombectomy in acute stroke, aneurysm coiling, mechanical thrombectomy in acute stroke.
How long does it take to perform a digital subtraction angiography?
Digital Subtraction Angiography is basically an angiography procedure. As in other angiographies, the patient is sedated if necessary in a sterile environment and processed in the supine position. With the work of an experienced team, the patient’s vascular structure is tried to be displayed.
The duration of the examination may take at least half an hour, depending on the patient’s condition, the area to be imaged, and the condition of the disease in this area.
The aim is to perform imaging in the shortest possible time without causing any harm to the patient. After imaging, the patient can be discharged after being observed for a while.
Digital Subtraction Angiography Procedure
Before Digital subtraction angiography is performed, the patient’s cardiovascular disease, diabetes, medications, any allergies to anything or iodinated contrast material, previous surgeries, and kidney functions are reviewed.
Strict aseptic conditions are provided in the technical preparations made while the patient is being put into practice and in the clothes that the patient should wear. The patient lies on the bed in such a way as to ensure the ease of maneuver of the Radiologist who will perform the application. Depending on the situation or the procedure to be applied, the patient can be sedated or put to sleep with general anesthesia.
When starting Digital subtraction angiography, X-ray images are taken before the contrast agent is applied to the target area where the vascular structure is desired to be revealed. Anesthesia is applied to the puncture site to reach the target area. Usually, ultrasound-guided puncture is performed. From here, the introducer, which is inserted with a kit, is reached to the targeted area. X-ray images are taken successively while the contrast agent is injected into the target area. Thanks to the machine, these two images are extracted from each other and the vessels in the target area are clearly displayed.
After the procedure is finished, the introducer is removed. Possible bleeding at the exit site is stopped under control. The patient is observed for a while for follow-up.
Complications of Digital Subtraction Angiography
Although digital subtraction angiography is a gold standard imaging method that shows the blood supply of vessels and regions, it is ultimately an invasive procedure. Local and systemic complications may be encountered during the imaging process.
Locally, it may cause local tissue damage at the puncture site. There is a risk of thrombus formation here. Some vascular problems such as pseudoaneurysm and arteriovenous fistulas may be encountered.
During the application, there are risks of occlusion of the vein, rupture of the veins due to intravascular clot throwing air. Apart from these, toxic exposure of the contrast agent applied to the kidneys may also occur.
As predicted in every surgical intervention, the patient may also experience anxiety and anxiety-related blood pressure drop, nausea, dizziness and pain during the procedure.
