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What Do Flow Voids Mean on an SFT MRI Report?

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A "flow void" or "highly vascular" note on your solitary fibrous tumor MRI simply means the tumor has a rich blood supply. This is an expected feature of SFTs and not a sign of aggression. Doctors use this information to plan a safe surgery, often using embolization to reduce bleeding.

Key Takeaways

  • • A highly vascular tumor means it has grown a dense network of blood vessels to sustain its growth.
  • • Flow voids are dark spots on an MRI caused by fast-moving blood traveling through the tumor's vessels.
  • • These vascular features are normal for SFTs and do not indicate that the tumor is more aggressive.
  • • Surgeons often use a procedure called pre-operative embolization to safely block the tumor's blood supply before removal.
  • • Knowing about the blood supply helps your surgical team plan a safe gross total resection while minimizing bleeding.

When you read an MRI report for a solitary fibrous tumor (SFT) that mentions “flow voids” and describes the tumor as “highly vascular,” it means your tumor has a very rich blood supply [1][2][3]. Highly vascular indicates that the tumor has grown a dense network of blood vessels to feed itself [4]. A flow void is simply how these active blood vessels appear on the MRI scan—the blood is moving so fast through the vessels that the MRI machine registers a dark, empty spot, or “void,” instead of a clear picture of the tissue [1][3].

Why SFTs Are Highly Vascular

SFTs are uniquely prone to growing an extensive network of blood vessels [5][6]. Under a microscope, pathologists often see a specific pattern of branching blood vessels within SFTs, historically called a staghorn pattern because the vessels branch out like the antlers of a deer [4][5].

Because SFTs have this rich blood supply, imaging scans like MRIs will clearly highlight this vascularity [7][8]. The appearance of flow voids is actually a helpful clue for radiologists. For example, if an SFT is located in the brain or spine, flow voids help doctors differentiate it from other central nervous system tumors, such as meningiomas, which may not always have the same kind of rapid, high-volume blood flow [1][9].

What This Means for Your Surgery

Seeing “highly vascular” on your report might sound alarming, but it is a normal and expected characteristic of this specific type of tumor. It does not necessarily mean the tumor is more aggressive [10][11]. Instead, it means the tumor requires careful surgical planning. The main challenge with removing a tumor that has a rich blood supply is the risk of significant bleeding during the operation [10][12].

To manage this risk, your surgical team will likely use the information from your MRI to plan strategies that control blood flow before they even make an incision.

Pre-Operative Embolization

If your MRI shows prominent flow voids, your surgeon may recommend a procedure called pre-operative embolization [3][13].

  • What it is: Embolization is a minimally invasive procedure performed before your main surgery, typically 1 to 3 days in advance. A specialist threads a tiny tube (catheter) through your blood vessels to reach the ones feeding the tumor. They then inject tiny particles or a special glue to block off these vessels [3][14].
  • Why it helps: By cutting off the blood supply to the tumor ahead of time, the tumor is devascularized. This significantly reduces the amount of bleeding during your actual surgery, making it safer and easier for the surgeon to remove the tumor completely [11][10][12].
  • Important considerations: While embolization makes the main surgery safer, it is a distinct medical procedure with its own potential risks, such as vessel damage or, depending on the tumor’s location, off-target blockage of healthy vessels [3]. Your care team will review these risks with you based on exactly where your tumor is located.

Complete removal, known as gross total resection, is the most important treatment goal for an SFT [13][15]. Knowing about the tumor’s blood supply in advance gives your care team the blueprint they need to achieve this goal safely [16].

Frequently Asked Questions

What is a flow void on an MRI report?
A flow void is a dark, empty spot on an MRI scan caused by fast-moving blood. It indicates that the tumor has a rich, active blood supply and helps radiologists identify the specific type of tumor you have.
Does a highly vascular SFT mean the tumor is more aggressive?
No, a highly vascular tumor is a normal and expected characteristic of a solitary fibrous tumor. It does not mean the cancer is more aggressive, but it does mean your surgical team will carefully plan your operation to manage potential bleeding.
Why might I need pre-operative embolization for an SFT?
Your surgeon may recommend embolization to block off the blood vessels feeding the tumor 1 to 3 days before your main surgery. This significantly reduces the risk of heavy bleeding during the operation, making it safer to remove the tumor completely.
How do flow voids help doctors diagnose an SFT?
Flow voids clearly highlight the tumor's rich blood supply. Because SFTs have unique blood vessel structures, seeing these flow voids helps doctors differentiate an SFT from other tumors, such as meningiomas, which often have different blood flow patterns.

Questions for Your Doctor

  • • Based on my MRI, are the flow voids or vascularity significant enough to require a pre-operative embolization?
  • • If I need embolization, who will perform the procedure and when will it happen relative to my main surgery?
  • • What are the specific risks associated with embolization for a tumor in my specific location?
  • • How does the blood supply of my tumor affect the anticipated blood loss during surgery, and will I need to prepare for a potential blood transfusion?

Questions for You

  • • Did the radiologist report mention any specific major blood vessels that are feeding the tumor or positioned very close to it?
  • • Are you experiencing any symptoms (like headaches, localized pain, or swelling) that might be related to where the tumor is drawing its blood supply?
  • • Have you ever had a history of bleeding issues, or are you taking any blood-thinning medications that you need to discuss with your surgical team?

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This page explains MRI terminology for solitary fibrous tumors for educational purposes only. Always discuss your specific imaging results and surgical plan with your radiologist and surgeon.

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