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 in the brain. A contrast agent is given to the body for imaging. When the contrast material reaches the desired area through the blood vessels, X-ray images of this area are taken. The device processes these images through a technique called “subtraction”. As a result of this procedure, the structure of the blood vessels in the area and the degree of blood supply can be clearly seen.
Digital subtraction angiography (DSA) is considered the “gold standard” in imaging for detecting blood flow problems. 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 contrast material administered. However, this risk is similar to that of other invasive imaging methods.
What are the benefits of digital subtraction angiography?
Digital subtraction angiography, a fluoroscopic imaging technique, has been used safely since the 1970s. Thanks to this technique, which shows the blood supply in the desired area, the vascular structure and blood supply can be seen extremely clearly in real time of the respective area.
To provide these images, the image of the target area (mask image) is taken before the contrast agent is administered. Thus, the device displays the anatomy of the area and foreign bodies (stent, surgical clips, etc.), if any, as a normal radiological image. A contrast substance is then injected. Images are taken consecutive to the injection. These images and the mask images undergo a subtraction procedure. As a result, only areas filled with contrast material appear. These areas are the vascular structures and the areas fed by the blood flowing through these veins.
The fact that interventional radiology achieves better results over time than open procedures increases the number of indications for such examinations. Currently, digital subtraction angiography, which is mainly used for endovascular aneurysm repair, arterial stenting, thrombectomy, arterial balloon angioplasty, endovascular embolization, is an effective technique in the treatment process, as well as in the diagnosis of diseases by a specialist.
When is digital subtraction angiography used?
Digital subtraction angiography is used to both detect and treat pathologies of blood vessels and vasculature. 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 are negative.
Digital subtraction angiography can be used for the treatment of preoperative embolization of vascular tumors, embolization of fistulas/arteriovenous malformations, endovascular treatments for vasospasm as a complication of subarachnoid hemorrhage, intracranial/extracranial stent placement, mechanical thrombectomy in acute stroke, coiling aneurysms, mechanical thrombectomy in acute stroke.
How long does digital subtraction angiography take?
Digital subtraction angiography is basically an angiography procedure. As with other angiograms, the patient is sedated, if necessary, in a sterile environment and the procedure is performed with the patient in the supine position. Through the work of an experienced team, an attempt is made to visualize the vascular structure of the patient.
The duration of the examination can last at least half an hour, depending on the condition of the patient, the area to be examined and the state of the disease in this area.
The goal is to perform the imaging in the shortest possible time, without causing any discomfort to the patient. After the procedure, the patient can be discharged after being observed for a period of time.
Digital subtraction angiography procedure
Before digital subtraction angiography is performed, the patient’s cardiovascular disease, diabetes, medications, allergies to anything or iodinated contrast material, previous surgeries, and kidney function are reviewed.
Strict aseptic conditions are ensured in the technical preparations made while the patient is prepared and changed into the clothes prepared for the procedure. The patient is placed on the bed in such a way as to ensure ease of maneuver for the radiologist who will perform the application.
Depending on the situation or the procedure to be applied, the patient may be sedated or given general anesthesia
.
When digital subtraction angiography is started, X-ray images are taken before the contrast material is applied to the target area where the vascular structure is to be examined. Anesthesia is applied to the puncture site to reach the target area. Ultrasound-guided puncture is usually performed. From here, the insertion device, which is inserted with the help of a kit, is reached in the targeted area. X-ray images are taken successively while the contrast agent is injected into the target area. Thanks to the device, these two images are extracted from each other, and the vessels in the target area are clearly displayed.
After the procedure is completed, the insertion device is removed. Any bleeding at the exit site is kept under control. The patient is kept under observation for a period of time for monitoring.
Complications of digital subtraction angiography
Although digital subtraction angiography is considered a “gold standard” imaging method that shows the blood supply to vessels and areas in the body, it is, after all, an invasive procedure. Local and systemic complications may occur during the imaging procedure.
Locally, it can cause local tissue damage at the puncture site. There is a risk of thrombus formation here. Some vascular problems such as pseudo-aneurysm and arteriovenous fistulas may occur.
During application, there are risks of vein occlusion, vein rupture due to an intravascular clot pushing air. Apart from these, toxic exposure of the contrast material applied to the kidneys can also occur.
As expected in any surgery, the patient may also experience anxiety and anxiety-related low blood pressure, nausea, dizziness, and pain during the procedure.