MR-guided sclerotherapy of low-flow vascular malformations using T2 -weighted interrupted bSSFP (T2 W-iSSFP): comparison of pulse sequences for visualization and needle guidance

Magnetic resonance - guided treatment of low-flow vascular malformations and the technologies to potentiate adoption

Vascular malformations are congenital, non-neoplastic lesions that arise secondary to defects in angiogenesis. Vascular malformations are divided into high-flow (arteriovenous malformation) and low-flow (venous malformations and lymphatic malformations). Magnetic resonance imaging (MRI) is the standard for pre-and post-intervention assessments, while ultrasound (US), X-ray fluoroscopy and computed tomography (CT) are used for intra-procedural guidance. Sclerotherapy, an image-guided therapy that involves the injection of a sclerosant directly into the malformation, is typically the first-line therapy for treating low-flow vascular malformations. Sclerotherapy induces endothelial damage and necrosis/fibrosis with eventual involution of the malformation. Image-guided thermal therapies involve freezing or heating target tissue to induce cell death and necrosis. MRI is an alternative for intra-procedural guidance and monitoring during the treatment of vascular malformations. MR can provide dynamic, multiplanar imaging that delineates surrounding critical structures such as nerves and vasculature. Multiple studies have demonstrated that MR-guided treatment of vascular malformations is safe and effective. This review will detail (1) the use of MR for the classification and diagnosis of vascular malformations, (2) the current literature surrounding MR-guided treatment of vascular malformations, (3) a series of cases of MR-guided sclerotherapy and thermal ablation for the treatment of vascular malformations, and (4) a discussion of technologies that may potentiate interventional MRI adoption including high intensity focused ultrasound and guided laser ablation.

MR-Guided Sclerotherapy for the Treatment of Low-Flow Vascular Malformations

Low-flow vascular malformations are congenital lesions that can occur throughout the body. Treatment of these lesions is indicated to ameliorate pain, cosmetic disfigurement, and functional impairment. The first-line treatment of low-flow vascular malformations is percutaneous sclerotherapy. Traditionally, sclerotherapy is performed with a combination of ultrasound and fluoroscopy. However, malformations that are deep in the abdomen and pelvis or are obscured by overlying fascia or scar may be difficult to be visualized with ultrasound and fluoroscopy. MR-guided sclerotherapy has emerged as an alternative modality that can be used to needle guidance and sclerosant monitoring. In this review, we discuss the historical and current use of MR-guided sclerotherapy for the treatment of low-flow vascular malformations.

Real-time MRI-guided percutaneous sclerotherapy treatment of venous low-flow malformations in the head and neck

Purpose This manuscript describes the technique of real-time MRI-guided sclerotherapy for low-flow venous malformations in the head and neck based on our institutional experience. Materials and methods Ethanolamine oleate is used as the sclerosant and is mixed with gadolinium for visualization during the procedure. The five procedural steps include: (I) an initial tri-plane T2-weighted sequence to visualize the lesion; (II) a T1 FSE or trueFISP sequence to assess needle placement and advancement within the lesion; (III) a tri-plane T1 FLASH sequence to monitor sclerosant injection; (IV) a T1 FSE or VIBE sequence to assess sclerosant coverage of the malformation before needle removal; (V) a post-procedural tri-plane T1 fat-saturated sequence to confirm sclerosant coverage of the lesion. Periprocedural medications typically include steroids, antibiotic prophylaxis, and non-steroidal anti-inflammatory medication. Patients are typically admitted for overnight observation. Conclusion Real-time MRI-guided sclerotherapy for low-flow venous malformations in the head and neck is effective and safe.

MR-guided percutaneous sclerotherapy of low-flow vascular malformations: Clinical experience using a 1.5 tesla MR system

PURPOSE

To demonstrate the feasibility, safety, and effectiveness of image-guided sclerotherapy of low-flow vascular malformations using a 1.5 Tesla (T) MR scanner with real-time imaging capability and in-suite fluoroscopy.

MATERIALS AND METHODS

Thirty-three procedures were performed with real-time 1.5T MR-guidance on 22 patients with a vascular malformation in the neck (n = 2), chest (n = 6), abdomen and pelvis (n = 15), and extremities (n = 11). Quantitative analysis was performed for changes in (a) planning time, (b) targeting time (interval between needle skin puncture and lesion access), (c) intervention time (interval between needle skin puncture and needle removal), and (d) total procedure time. Qualitative analysis was performed for (a) success of therapy and (b) occurrence of complications.

RESULTS

Technical success was achieved in 29 of 33 procedures. The average planning time did not significantly change between the first seven procedures and the last seven procedures (P = 0.447). The average targeting time decreased by 0:24:45 (hours:minutes:seconds) (P = 0.043), the average intervention time decreased by 0:26:58 (P = 0.022), and the average procedure time decreased by 0:28:41 (P = 0.046) when comparing the first seven procedures and the last seven procedures. Overall, there was an improvement in the patients' predominant symptoms following 82% of procedures, including a significant decrease in average pain following therapy (P < 0.001). There was a minor complication rate of 3% with no major complications.

CONCLUSION

MR-guided percutaneous sclerotherapy seems to be a safe, effective, and versatile technique for treating low-flow vascular malformations.

LEVEL OF EVIDENCE

3 J. Magn. Reson. Imaging 2017;45:1154-1162.