Initial Results of Image-Guided Percutaneous Ablation as Second-Line Treatment for Symptomatic Vascular Anomalies

Abstract

Purpose: The purpose of this study was to determine the feasibility, safety, and early effectiveness of percutaneous image-guided ablation as second-line treatment for symptomatic soft-tissue vascular anomalies (VA).

Materials and methods: An IRB-approved retrospective review was undertaken of all patients who underwent percutaneous image-guided ablation as second-line therapy for treatment of symptomatic soft-tissue VA during the period from 1/1/2008 to 5/20/2014. US/CT- or MRI-guided and monitored cryoablation or MRI-guided and monitored laser ablation was performed. Clinical follow-up began at one-month post-ablation.

Results: Eight patients with nine torso or lower extremity VA were treated with US/CT (N = 4) or MRI-guided (N = 2) cryoablation or MRI-guided laser ablation (N = 5) for moderate to severe pain (N = 7) or diffuse bleeding secondary to hemangioma-thrombocytopenia syndrome (N = 1). The median maximal diameter was 9.0 cm (6.5-11.1 cm) and 2.5 cm (2.3-5.3 cm) for VA undergoing cryoablation and laser ablation, respectively. Seven VA were ablated in one session, one VA initially treated with MRI-guided cryoablation for severe pain was re-treated with MRI-guided laser ablation due to persistent moderate pain, and one VA was treated in a planned two-stage session due to large VA size. At an average follow-up of 19.8 months (range 2-62 months), 7 of 7 patients with painful VA reported symptomatic pain relief. There was no recurrence of bleeding at five-year post-ablation in the patient with hemangioma-thrombocytopenia syndrome. There were two minor complications and no major complications.

Conclusion: Image-guided percutaneous ablation is a feasible, safe, and effective second-line treatment option for symptomatic VA.

Keywords: CT; Cryoablation; Laser ablation; MRI; Vascular anomaly; Vascular malformation; Vasoproliferative neoplasm.

Figure 1. Planned two-stage US/CT-guided cryoablation of a hemangioendothelioma of the right subscapularis muscle in a patient with Kasabach-Merritt Syndrome

(A) Pre-ablation gadolinium-enhanced axial T1-weight spoiled gradient echo (SPGR) MRI and (B) 3D CTA reconstruction of the vascular anomaly (white arrow). (C) Intra-procedural non-contrast enhanced axial CT during ablation session number one demonstrates zone of hypoattenuation corresponding to the ice-ball (white arrow). (D) Two-month post-ablation gadolinium-enhanced coronal T1-weighted spoiled gradient echo (SPGR) MRI demonstrates residual enhancement of the superior portion of the vascular anomaly (white arrow). (E) Intra-procedural non-contrast enhanced axial CT during ablation session number two demonstrates zone of hypoattenuation corresponding to the ice-ball (white arrow). (F) Six-month post-ablation gadolinium enhanced T1-weighted spoiled gradient echo (SPGR) MRI demonstrates significant reduction in size and no further irregular enhancement of the vascular anomaly (white arrow).

Figure 2. MRI-guided cryoablation and laser ablation of a slow-flow vascular malformation of the right extensor hallucis longus and extensor digitorum longus muscles

(A) Pre-ablation T2-weighted MRI demonstrates abnormal T2 signal within the vascular anomaly (white arrow). (B) Intra-procedural T1-weighted MRI using a fast 3D gradient-echo sequence during cryoablation shows signal dropout within the ice ball (white arrow). (C) Immediate post-ablation gadolinium-enhanced axial T1-weighted spoiled gradient echo (SPGR) MRI demonstrates minimal enhancement of the vascular anomaly. Due to incomplete resolution of pain at three months post cryoablation, (D) follow-up gadolinium-enhanced axial T1-weighted SPGR MRI demonstrates enhancing draining veins within the center of vascular anomaly (arrow) with persistent drainage to the superficial venous system (arrowhead). (E, F) Patient was re-treated with MRI-guided laser ablation to ablate the central draining outflow veins from the center of the vascular anomaly. (E) Real-time MRI using a using a balanced steady-state free precession (bSSFP) gradient echo sequence was utilized for needle placement and demonstrates needle/laser fiber localization within the center of the vascular anomaly (arrow). (F) Immediate post-ablation gadolinium-enhanced axial T1-weighted SPGR MRI demonstrates loss of enhancement and ablation of the draining outflow veins within the center of the vascular anomaly and a peripheral hyperemic rim (arrow).

Figure 3. MRI-guided laser ablation of a slow-flow vascular malformation in the soft tissue between the right rhomboid and subscapularis muscles

(A, B) Pre-ablation (A) axial T2-weighted and (B) gadolinium-enhanced axial T1-weight spoiled gradient echo (SPGR) MRI demonstrates heterogeneous abnormal T2 signal (A, white arrow) and contrast enhancement (B, white arrow) within the small vascular anomaly. (C, D) Intra-procedural coronal oblique (C) phase imaging demonstrates real-time tissue heating using proton resonance frequency MR thermometry and (D) thermal damage map calculated from this using the Arrhenius equation to estimate the ablation zone. (E, F) One-year post-ablation (E) axial T2-weighted MRI and (F) gadolinium-enhanced axial T1-weight spoiled gradient echo (SPGR) MRI demonstrates no significant T2 signal (E, white arrow) and no enhancement of the vascular anomaly (F, white arrow).