From the Guidelines
Fibromuscular Dysplasia (FMD) on Computed Tomography Angiography (CTA) of the neck is a significant finding that requires prompt attention and management to prevent complications such as stroke, arterial dissection, or aneurysms. FMD is a non-inflammatory, non-atherosclerotic arterial disease that causes abnormal cell growth in artery walls, typically appearing as a "string of beads" pattern in the carotid or vertebral arteries on CTA, showing alternating areas of narrowing and dilation 1. This condition predominantly affects middle-aged women and can lead to serious complications, with the US FMD registry noting that 13.4% of patients had experienced transient ischemic attack (TIA), 5% had experienced amaurosis fugax, 12% had experienced cervical artery dissection, and 9.8% had had a stroke 1.
Key Considerations
- FMD can involve the extracranial carotid, vertebral, and renal arteries, and patients diagnosed with FMD should undergo comprehensive vascular imaging to check for involvement of other arterial beds 1.
- Management typically includes antiplatelet therapy, such as aspirin 81-325mg daily, blood pressure control if hypertensive, and regular imaging surveillance 1.
- For symptomatic stenosis, interventional procedures like angioplasty may be considered, and regular follow-up with a vascular specialist is essential for monitoring disease progression and adjusting treatment as needed.
Imaging Findings
- CTA can demonstrate vessel narrowing, pseudoaneurysm, or an intimal flap in dissection, and is a useful tool for diagnosing FMD 1.
- The "string of beads" pattern on angiography imaging is characteristic of FMD, and is caused by multiple fibrous webs that can serve as a nidus for platelet deposition or obstruct flow, resulting in thromboembolic TIA or ischemic stroke 1.
From the Research
Significance of Fibromuscular Dysplasia (FMD) on Computed Tomography Angiography (CTA) of the neck
- FMD is a nonatherosclerotic, noninflammatory arterial disease that can affect the carotid arteries, leading to stenosis, dissection, or aneurysm formation 2, 3, 4, 5, 6
- The prevalence of cervicocranial FMD is estimated to be around half of the prevalence of symptomatic renal artery FMD, which is about 4/1000 2
- CTA of the neck can be used to diagnose FMD, although the gold standard for diagnosis is catheter angiography 2, 4, 6
- CTA can show the characteristic "string of beads" appearance of FMD, as well as other morphologic features such as stenosis, tortuosity, and aneurysm formation 3, 4, 6
- The use of CTA in diagnosing FMD is important, as it can help identify patients who may be at risk for complications such as dissection or stroke 3, 4, 5
Diagnostic Accuracy of CTA for FMD
- CTA is a noninvasive modality that can be used to diagnose FMD, although its accuracy may be lower than that of catheter angiography 2, 4, 6
- The sensitivity and specificity of CTA for diagnosing FMD are not well established, although it is considered to be a useful tool in the diagnostic workup of patients with suspected FMD 3, 4, 6
- The use of CTA in combination with other diagnostic modalities, such as ultrasonography and magnetic resonance angiography, may improve the accuracy of diagnosis 6
Clinical Implications of FMD on CTA of the neck
- FMD can lead to significant morbidity and mortality if left untreated, particularly in patients who develop dissection or aneurysm formation 3, 4, 5
- The diagnosis of FMD on CTA of the neck can help identify patients who may be at risk for these complications, allowing for early intervention and treatment 3, 4, 5
- Treatment options for FMD include percutaneous balloon angioplasty, stent placement, and surgical repair, although the optimal treatment approach is not well established 4, 5