CLINICAL STUDY Multimodality Image-Guided Sclerotherapy of Low-Flow Orbital Vascular Malformations: Report of Single-Center Experience Samer Harmoush, MD, Ponraj Chinnadurai, MBBS, MMST, Kamel El Salek, MD, Zeyad Metwalli, MD, Honey Herce, MD, Amit Bhatt, MD, Paul Steinkuller, MD, Timothy Vece, MD, Shakeel Siddiqui, MD, Ashwin Pimpalwar, MD, Douglas Marx, MD, Michel Mawad, MD, and Sheena Pimpalwar, MD, FRCR ABSTRACT Purpose: To evaluate the role of multimodality imaging tools for intraprocedural guidance and outcome evaluation during sclerotherapy of low-flow orbital vascular malformations. Materials and Methods: A retrospective review was performed of 17 consecutive patients with low-flow orbital malformations (14 lymphatic, 2 venous, and 1 venolymphatic) who underwent multimodality image-guided sclerotherapy between November 2012 and May 2015. Sclerotherapy technique, image guidance tools, and complications were recorded. Sclerotherapy outcome was evaluated using clinical response, magnetic resonance (MR) image–based lesion volumetry, and proptosis quantification. Results: There were 22 sclerotherapy sessions performed. Intraprocedural ultrasound (US), fluoroscopy, cone-beam computed tomography (CT) and MR image fusion were used for image guidance with 100% technical success. Resolution of presenting symptoms was observed in all patients at 1-month follow-up. Four major sclerotherapy complications were successfully managed. Statistically significant reduction in lesion volume (P ¼ .001) and proptosis (P ¼ .0117) by MR image analysis was achieved in all patients in whom 3-month follow-up MR imaging was available (n ¼ 13/17). There was no lesion recurrence at a median follow-up of 18 months (range, 8–38 mo). Conclusions: Multimodality imaging tools, including US, fluoroscopy, cone-beam CT, and MR fusion, during sclerotherapy of low-flow orbital malformations provide intraprocedural guidance and quantitative image-based evaluation of treatment outcome. ABBREVIATIONS DAP = dose area product, IOP = intraocular pressure, STS = sodium tetradecyl sulfate The infiltrative nature of low-flow orbital vascular malformations makes complete surgical resection chal- lenging, with risks of nerve damage, scarring, infection, and incomplete resection (1,2). During long-term follow- up, these malformations have a tendency to recur, as reported in the surgical literature with recurrence rates of 58% and 71% at a mean follow-up of 3.4 years and 7.2 years, respectively (1,2). Sclerotherapy has been increas- ingly used as a minimally invasive treatment option for the management of these malformations (3–12). The main challenges of sclerotherapy are safe access into retrobulbar lesions, management of orbital compartment syndrome after sclerotherapy, and lack of standardized evaluation of treatment response (13). The purpose of this study was to evaluate the role of multimodality & SIR, 2016 J Vasc Interv Radiol 2016; XX:]]]–]]] http://dx.doi.org/10.1016/j.jvir.2016.02.036 P.C. is a full-time research scientist for and receives a salary from Siemens Medical Solutions USA, Inc (Hoffman Estates, Illinois). None of the other authors have identified a conflict of interest. Figures E1–E5 and Table E1 and Appendix A are available online at www. jvir.org. From the Departments of Radiology (S.H., K.E.S. Z.M., M.M.), Ophthalmology (H.H., A.B., P.S.), Pediatric Pulmonology (T.V.), Pediatric Anesthesia (S.S.), and Pediatric Oculofacial Surgery (D.M.) and Division of Pediatric Surgery (A.P.), Michael E. DeBakey Department of General Surgery, Baylor College of Medicine, Houston, Texas; Angiography Division (P.C.), Siemens Medical Solutions USA, Inc, Hoffman Estates, Illinois; and Division of Interventional Radiology (S.P.), Department of Radiology, Texas Children’s Hospital, 6621 Fannin Street, Houston, TX 77030. Received September 10, 2015; final revision received and accepted February 29, 2016. Address correspondence to S.P.; E-mail: ashwinsheena@hotmail.com