Diagnosing a dural arteriovenous fistula (DAVF) is a step-by-step process that involves various tests and examinations. The goal is not only to confirm the presence of a DAVF, but also to understand its size, location, and the precise pattern of abnormal blood flow. This helps doctors formulate a suitable treatment plan.
Medical History and Physical Examination
The first step in diagnosing a DAVF typically involves a thorough review of your medical history. Your doctor will ask you detailed questions about your symptoms, including their nature, duration, and severity. They may also ask you about your overall health, including any other medical conditions you may have and any medications you are currently taking.
In addition, they might inquire about any history of trauma, infection, or surgery. This is because these factors can sometimes contribute to the development of a DAVF. For instance, a prior injury or surgery to the head might damage the blood vessels, leading to the abnormal connections seen in DAVFs. Similarly, certain infections can also affect the blood vessels in the dura.
In the process of diagnosing a DAVF, understanding your symptoms plays a crucial role. The symptoms of a DAVF can vary greatly from person to person, depending on factors like the location of the fistula and the pattern of abnormal blood flow.
Common symptoms that your doctor may ask about include:
Headaches or neck pain: These can range from mild to severe and might be the first noticeable sign of a DAVF.
Pulsatile tinnitus: This is a condition where you hear a rhythmic whooshing or humming sound in one or both of your ears. It is often caused by altered blood flow, such as that seen in a DAVF.
Vision changes: This could involve blurry vision, vision loss, or even double vision. These changes can occur if the DAVF affects the blood supply to your eyes.
Neurological symptoms: These can encompass a wide range of issues, from muscle weakness and balance difficulties to more severe problems like seizures or even stroke-like symptoms. These occur due to the altered blood flow in the brain.
Following this, your doctor will carry out a physical examination. They will likely focus on your neurological health, looking for signs of issues such as muscle weakness, vision changes, or balance difficulties. This can involve testing your reflexes, assessing your sense of touch and pain, and examining your eyes, among other things. These checks are important because DAVFs can affect your neurological function due to the altered blood flow in your brain.
Imaging Tests
Several types of imaging tests can help visualize the blood vessels in the brain and detect any abnormalities. These include:
Magnetic Resonance Imaging (MRI): An MRI is a non-invasive imaging technique that employs powerful magnets and radio waves to generate comprehensive images of the brain and spinal cord. These images can often highlight the presence of a DAVF or illustrate the impact it has on the brain or spinal cord. MRI can also be combined with angiography (MRA) to visualize blood vessels and the flow of blood, offering a detailed view of any abnormal vascular structures associated with DAVF.
Computed Tomography (CT): A CT scan uses X-ray technology to capture images from various angles, creating cross-sectional views of the brain. These can reveal abnormalities or changes in the brain that might be indicative of a DAVF. Additionally, a CT scan can be combined with angiography (CTA) to provide detailed images of the blood vessels, enhancing the visualization of a possible DAVF.
Digital Subtraction Angiogram (DSA): DSA is a more invasive procedure that is often used when other imaging tests are inconclusive or when precise details of the blood vessels are needed for treatment planning. In this test, a contrast dye is injected into your blood vessels through a catheter, usually inserted in your groin. As the dye travels through your vessels, a series of X-ray images are taken, which can provide a clear, detailed view of the blood flow and reveal the exact location and characteristics of a DAVF. While more involved and with more potential risks than other imaging studies, DSA is considered the “gold standard” for diagnosing DAVFs due to its high level of detail.