TECHNICAL NOTE J Neurosurg 129:1217–1222, 2017 P reciPitating hydrophobic injectable liquid (PHIL; MicroVention) is a newly available liquid embolic agent for endovascular use. PHIL contains a co- polymer [poly(lactide co-glycolide) and poly(hydroxyethyl methacrylate)], which is suspended in dimethyl sulfoxide (DMSO). An iodine (triiodophenol) component is cova- lently bonded to the polymer, making it radiopaque. CE (Conformité Européenne) approval for its use in intracra- nial vascular malformations was obtained in July 2014. We describe our initial experience with the treatment of intracranial vascular shunts using PHIL. Methods Between July 2015 and December 2015, 11 patients un- derwent PHIL endovascular embolization. Five patients harbored arteriovenous malformations (AVMs), and 4 had dural arteriovenous fstulas (DAVFs). One had a carotid- cavernous fstula (CCF), and the remaining patient had a pial AVF. Clinical Presentation and Angioarchitecture Of the 5 AVMs, 3 were ruptured, resulting in intracra- ABBREVIATIONS AVF = arteriovenous fistula; AVM = arteriovenous malformation; CCF = carotid-cavernous fistula; DAVF = dural AVF; DMSO = dimethyl sulfoxide; NBCA = N-butyl cyanoacrylate; PHIL = precipitating hydrophobic injectable liquid. SUBMITTED February 21, 2016. ACCEPTED June 2, 2017. INCLUDE WHEN CITING Published online December 1, 2017; DOI: 10.3171/2017.6.JNS16447. Precipitating hydrophobic injectable liquid embolization of intracranial vascular shunts: initial experience and technical note Shriram Varadharajan, DM, 1 Arvinda Hanumanthapura Ramalingaiah, DM, 1 Jitender Saini, DM, 1 Arun Kumar Gupta, MD, 1 B. Indira Devi, MCh, 2 and Ullas V. Acharya, DM 1 Departments of 1 Neuroimaging and Interventional Radiology and 2 Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India Precipitating hydrophobic injectable liquid (PHIL) is a newly available liquid embolic agent for endovascular therapy. It is nonadhesive and composed of a biocompatible polymer dissolved in dimethyl sulfoxide solvent and bonded covalently with iodine. In this report, the authors present their preliminary experience using PHIL in the treatment of intracranial vascular shunts. Between July 2015 and December 2015, 11 patients underwent endovascular embolization using the PHIL embolic agent. Five patients had arteriovenous malformations, 4 had dural arteriovenous fstulas, 1 patient had a carotid- cavernous fstula, and 1 patient had a pial arteriovenous fstula. Clinical features, angioarchitectural characteristics, procedural details, and periprocedural complications were included in the analysis. Complete or near-complete obliteration of the nidus or fstulas was achieved in 8 of these patients. Partial embolization (approximately 80% in 2 and 30% in 1) was attained in the other 3 patients. Satisfactory venous penetration after nidal embolization was achieved in all patients. In 1 patient, the microcatheter could not be retrieved. No other major compli- cations related to PHIL injection were noted during the procedure or periprocedural period. Clinical follow-up ranging from 8 months to 1 year showed good outcomes in all but 1 patient, who experienced an intraventricular hemorrhage 6 weeks after embolization. PHIL appears to be an effective alternative embolic material with certain advantages over other available liquid embolic agents. Further studies with adequate follow-up are required to fully evaluate its safety and ef fcacy. https://thejns.org/doi/abs/10.3171/2017.6.JNS16447 KEY WORDS precipitating hydrophobic injectable liquid; PHIL; embolization; vascular malformations; brain; surgical technique; interventional neurosurgery J Neurosurg Volume 129 • November 2018 1217 ©AANS 2018, except where prohibited by US copyright law