Ryan Lokken, MD

Associate Professor
Assoc Professor Clin Radiology


R. Peter Lokken earned his Master’s degree in Public Health at the Harvard School of Public Health (2006) and his MD (2007) from Harvard Medical School in Boston, MA. He completed a one-year Internal Medicine internship at UC San Diego (2008). Lokken’s four-year diagnostic radiology residency was at the Brigham and Women’s Hospital in Boston, MA (2008-2012). Lokken completed a one-year Interventional Radiology fellowship at UCSF in 2013. In 2013, he joined the University of Illinois Hospital Health & Science Center in Chicago as a radiologist specializing in vascular interventional radiology. In June 2018, he rejoined UCSF as an assistant professor of clinical radiology in the department’s Interventional Section.

Lokken is an associate editor for the Journal of Vascular and Interventional Radiology, the scientific journal of the Society for Interventional Radiology. His research focus is the investigation of clinical, genetic and immunological factors associated with outcomes of locoregional therapy for hepatocellular carcinoma and other malignancies.


Khela M, Kasir R, Lokken RP, Clark AJ, Theologis AA. Bilateral dual iliac screw pelvic fixation for adult spinal deformity: a case report of a superior gluteal artery pseudoaneurysm secondary to aberrant iliac screw trajectory. Spine Deform. 2023 Oct 26.
Wu X, Kwong A, Heller M, Lokken RP, Fidelman N, Mehta N. Cost-effectiveness analysis of interventional liver-directed therapies for downstaging of hepatocellular carcinoma before liver transplant. Liver Transpl. 2023 Aug 29.
Blackburn AF, Landinez GP, Kerlan RK, Lokken RP. Malposition of a Femoral Tunneled Dialysis Catheter through a Patent Foramen Ovale. Semin Intervent Radiol. 2023 Jun; 40(3):304-307.
Wu X, Lokken RP, Mehta N. Optimal treatment for small HCC (<3 cm): Resection, liver transplantation, or locoregional therapy? JHEP Rep. 2023 Aug; 5(8):100781.
Wu X, Heller M, Lokken RP, Fidelman N, Lam A. Socioeconomic and Survival Analysis of Radioembolization in Patients with Intrahepatic Cholangiocarcinoma: A Propensity Score-Adjusted Study. J Vasc Interv Radiol. 2023 05; 34(5):815-823.e1.
Qureshy Z, Lokken RP, Kakar S, Grab J, Mehta N, Sarkar M. Influence of progestin-only hormonal use on hepatocellular adenomas: A retrospective cohort study. Contraception. 2023 03; 119:109915.
Shah RJ, Alqadi MM, Duvvuri M, Kim YJ, Tyagi R, Lokken RP, Gaba RC. Clinical Outcomes and Patency after Transjugular Intrahepatic Portosystemic Shunt Reduction for Overshunting Adverse Events. J Vasc Interv Radiol. 2022 12; 33(12):1507-1512.
Elkhadragy L, Khabbaz RC, Muchiri RN, Totura WM, Samuelson JP, Whiteley HE, van Breemen RB, Lokken RP, Gaba RC. Pharmacokinetics and Early Tumor Response to Conventional Transarterial Chemoembolization with Sorafenib and Doxorubicin in a VX2 Rabbit Tumor Model. J Vasc Interv Radiol. 2022 10; 33(10):1213-1221.e5.
Kohlbrenner R, Schwertner AB, Vogel AR, Conrad M, Lokken RP. Large thrombosed portomesenteric venous aneurysm treated with pharmacomechanical thrombolysis combined with TIPS placement. CVIR Endovasc. 2022 Feb 08; 5(1):11.
Lokken RP, Conrad MB. Nonoperative Management of Unstable Patients with Solid Organ Injury: An Incompletely Mapped Frontier. J Vasc Interv Radiol. 2021 08; 32(8):1156-1157.
Speir EJ, Hills NK, Lokken RP. Accuracy of Disclosed Financial Relationships between Radiologists and Industry at the 2018 RSNA Annual Meeting. Radiology. 2021 08; 300(2):433-435.
Gaba RC, Khabbaz RC, Muchiri RN, Morrison JD, Elkhadragy L, Totura WM, Samuelson JP, Whiteley HE, Deaton RL, Nguyen PL, Sverdlov M, Johnson JJ, van Breemen RB, Lokken RP. Conventional versus drug-eluting embolic transarterial chemoembolization with doxorubicin: comparative drug delivery, pharmacokinetics, and treatment response in a rabbit VX2 tumor model. Drug Deliv Transl Res. 2022 05; 12(5):1105-1117.
Lokken RP, Kerlan RK, Chung YC, Chen YF, Mehta NJ, Yao FY, Fidelman N. Hepatic Toxicity After Selective Chemoembolization Is Associated With Decreased Survival Among Patients With Hepatocellular Carcinoma. AJR Am J Roentgenol. 2021 05; 216(5):1283-1290.
Schwertner A, Kohlbrenner RM, Seeley EJ, Lokken RP. Nonfibered Packing Coil Embolization of Pulmonary Artery Pseudoaneurysm Resulting in a Delayed Endobronchial Coil Migration. J Vasc Interv Radiol. 2021 04; 32(4):626-628.
Compadre AJ, Kohi M, Lokken RP, Blissett S, Harris IS, Lucero J, Rosenstein MG, Sobhani NC. Catheter-Directed Thrombolysis for Submassive Pulmonary Embolism in the Third Trimester of Pregnancy. JACC Case Rep. 2020 Oct; 2(12):1899-1904.
Losey AD, Lokken RP, Kolli KP, Kerlan RK, Taylor AG, Kohi MP. Embolization of Arterial-Portal Fistula to Treat Associated Hemobilia after Transjugular Liver Biopsy. Semin Intervent Radiol. 2020 Oct; 37(4):430-433.
Knox J, Kohlbrenner R, Kolli K, Fidelman N, Kohi MP, Lehrman E, Lokken RP, Zagoria R, Kerlan RK, LaBerge J, Taylor AG. Intermediate to Long-Term Clinical Outcomes of Percutaneous Cryoablation for Renal Masses. J Vasc Interv Radiol. 2020 Aug; 31(8):1242-1248.
Kord A, James E, Herren J, Gaba RC, Lokken RP. Esophagopulmonary fistula causing pulmonary arterial pseudoaneurysms and massive hemoptysis. Radiol Case Rep. 2020 Jul; 15(7):914-920.
Koethe Y, Lokken RP, Lehrman ED, Kerlan RK, Roberts JP, Rhee SJ, Kohi MP, Kolli KP. Overdilation of a 6-mm Self-Expanding Stent with a 10-mm Balloon-Expandable Stent Graft Preserves Failing Meso-Rex Bypass. J Vasc Interv Radiol. 2020 03; 31(3):521-523.
Park BV, Gaba RC, Huang YH, Chen YF, Guzman G, Lokken RP. Histology of Hepatocellular Carcinoma: Association with Clinical Features, Radiological Findings, and Locoregional Therapy Outcomes. J Clin Imaging Sci. 2019; 9:52.
Bremer WA, Lokken RP, Gaba RC, Bui JT. Arterial-portal fistula treated with hepatic arterial embolization and portal venous aneurysm stent-graft exclusion complicated by type 2 endoleak. Radiol Case Rep. 2019 Oct; 14(10):1301-1305.
Huang YH, Park BV, Chen YF, Gaba RC, Guzman G, Lokken RP. Locoregional Therapy of Hepatocellular-Cholangiocarcinoma versus Hepatocellular Carcinoma: A Propensity Score-Matched Study. J Vasc Interv Radiol. 2019 Sep; 30(9):1317-1324.
Patel DC, Gaba RC, Liu L, Lokken RP. Tissue plasminogen activator dose and pulmonary artery pressure reduction in catheter directed thrombolysis of submassive pulmonary embolism. PLoS One. 2019; 14(2):e0211701.
Darrow AW, Gaba RC, Lokken RP. Transhepatic Revision of Occluded Transjugular Intrahepatic Portosystemic Shunt Complicated by Endotipsitis. Semin Intervent Radiol. 2018 Dec; 35(5):492-496.
Khabbaz RC, Huang YH, Smith AA, Garcia KD, Lokken RP, Gaba RC. Development and Angiographic Use of the Rabbit VX2 Model for Liver Cancer. J Vis Exp. 2019 01 07; (143).
Gaba RC, Lokken RP, Zwanziger J, Girotti JA, Ray CE, Kashima K. Eight Years' Experience With a Radiology-Sponsored Medical Student Research Fellowship Program. J Am Coll Radiol. 2019 Feb; 16(2):224-227.
Gaba RC, Mendoza-Elias N, Regan DP, Garcia KD, Lokken RP, Schwind RM, Eichner M, Thomas FM, Rund LA, Schook LB, Schachtschneider KM. Characterization of an Inducible Alcoholic Liver Fibrosis Model for Hepatocellular Carcinoma Investigation in a Transgenic Porcine Tumorigenic Platform. J Vasc Interv Radiol. 2018 08; 29(8):1194-1202.e1.
Devulapalli KK, Fidelman N, Soulen MC, Miller M, Johnson MS, Addo E, El-Haddad G, Nutting C, Morrison J, Farsad K, Lokken RP, Gaba RC, Fleming J, Brown DB, Kwan SW, Rose SC, Pennycooke KA, Liu DM, White SB, Gandhi R, Lazar AA, Kerlan RK. 90Y Radioembolization for Hepatic Malignancy in Patients with Previous Biliary Intervention: Multicenter Analysis of Hepatobiliary Infections. Radiology. 2018 Sep; 288(3):774-781.
Khabbaz RC, Lokken RP, Chen YF, Lipnik AJ, Bui JT, Ray CE, Gaba RC. Albumin-Bilirubin and Platelet-Albumin-Bilirubin Grades Do Not Predict Survival After Transjugular Intrahepatic Portosystemic Shunt Creation. Cardiovasc Intervent Radiol. 2018 Jul; 41(7):1029-1034.
Morrison JD, Mendoza-Elias N, Lipnik AJ, Lokken RP, Bui JT, Ray CE, Gaba RC. Gastric Varices Bleed at Lower Portosystemic Pressure Gradients than Esophageal Varices. J Vasc Interv Radiol. 2018 May; 29(5):636-641.
Sheybani A, Gaba RC, Lokken RP, Berggruen SM, Mar WA. Liver Masses: What Physicians Need to Know About Ordering and Interpreting Liver Imaging. Curr Gastroenterol Rep. 2017 Oct 18; 19(11):58.
Hansmann J, Evers MJ, Bui JT, Lokken RP, Lipnik AJ, Gaba RC, Ray CE. Albumin-Bilirubin and Platelet-Albumin-Bilirubin Grades Accurately Predict Overall Survival in High-Risk Patients Undergoing Conventional Transarterial Chemoembolization for Hepatocellular Carcinoma. J Vasc Interv Radiol. 2017 Sep; 28(9):1224-1231.e2.
Gaba RC, Lokken RP, Hickey RM, Lipnik AJ, Lewandowski RJ, Salem R, Brown DB, Walker TG, Silberzweig JE, Baerlocher MO, Echenique AM, Midia M, Mitchell JW, Padia SA, Ganguli S, Ward TJ, Weinstein JL, Nikolic B, Dariushnia SR, Society of Interventional Radiology Standards of Practice Committee. Quality Improvement Guidelines for Transarterial Chemoembolization and Embolization of Hepatic Malignancy. J Vasc Interv Radiol. 2017 09; 28(9):1210-1223.e3.
Gaba RC, Kobayashi KR, Bui JT, Lokken RP, Lipnik AJ, Ray CE, Oberholzer J. Liver Track Embolization After Islet Cell Transplant: Comparison of Two Techniques. AJR Am J Roentgenol. 2017 May; 208(5):1134-1140.
Lakhoo J, Gunasekaran SS, Lokken RP, Lipnik AJ, Ray CE, Bui JT, Gaba RC. Does advanced chronic kidney disease impact transjugular intrahepatic portosystemic shunt efficacy and safety? Acta Gastroenterol Belg. 2017 Apr-Jun; 80(2):243-248.
Park BV, Gaba RC, Lokken RP. Liver Infarction after Drug-Eluting Embolic Transarterial Chemoembolization for Hepatocellular Carcinoma in the Setting of a Large Portosystemic Shunt. Semin Intervent Radiol. 2016 Dec; 33(4):337-341.
Vyas AR, Bui JT, Ray CE, Lokken RP, Gaba RC. Filter Eversion Technique for Removal of Option ELITE Inferior Vena Cava Filters. J Vasc Interv Radiol. 2016 Nov; 27(11):1718-1720.
Lokken RP, Fidelman N, Kolli KP, Kerlan RK. Safety and Efficacy of Doxorubicin Drug-Eluting Embolic Chemoembolization of Hepatocellular Carcinoma Supplied by Extrahepatic Collateral Arteries. J Vasc Interv Radiol. 2016 Nov; 27(11):1698-1704.
Lee AC, Mullany LC, Ladhani K, Uddin J, Mitra D, Ahmed P, Christian P, Labrique A, DasGupta SK, Lokken RP, Quaiyum M, Baqui AH, Projahnmo Study Group. Validity of Newborn Clinical Assessment to Determine Gestational Age in Bangladesh. Pediatrics. 2016 07; 138(1).
Lakhoo J, Bui JT, Lokken RP, Ray CE, Gaba RC. Transjugular Intrahepatic Portosystemic Shunt Creation and Variceal Coil or Plug Embolization Ineffectively Attain Gastric Variceal Decompression or Occlusion: Results of a 26-Patient Retrospective Study. J Vasc Interv Radiol. 2016 07; 27(7):1001-11.
Patel D, Ray CE, Lokken RP, Bui JT, Lipnik AJ, Gaba RC. Advanced Stent Graft Treatment of Venous Stenosis Affecting Hemodialysis Vascular Access: Case Illustrations. Semin Intervent Radiol. 2016 Mar; 33(1):39-45.
Lakhoo J, Bui JT, Zivin SP, Lokken RP, Minocha J, Ray CE, Gaba RC. Root Cause Analysis of Rebleeding Events following Transjugular Intrahepatic Portosystemic Shunt Creation for Variceal Hemorrhage. J Vasc Interv Radiol. 2015 Oct; 26(10):1444-53.
Lokken RP, Sadow CA, Silverman SG. Diagnostic yield of CT urography in the evaluation of young adults with hematuria. AJR Am J Roentgenol. 2012 Mar; 198(3):609-15.
Lokken RP, Wellenius GA, Coull BA, Burger MR, Schlaug G, Suh HH, Mittleman MA. Air pollution and risk of stroke: underestimation of effect due to misclassification of time of event onset. Epidemiology. 2009 Jan; 20(1):137-42.
Lokken RP, Gervais DA, Arellano RS, Tuncali K, Morrison PR, Tatli S, Mueller PR, Silverman SG. Inflammatory nodules mimic applicator track seeding after percutaneous ablation of renal tumors. AJR Am J Roentgenol. 2007 Oct; 189(4):845-8.
Jeon CY, Lokken RP, Hu FB, van Dam RM. Physical activity of moderate intensity and risk of type 2 diabetes: a systematic review. Diabetes Care. 2007 Mar; 30(3):744-52.
McConnell TS, Lokken RP, Steitz JA. Assembly of the U1 snRNP involves interactions with the backbone of the terminal stem of U1 snRNA. RNA. 2003 Feb; 9(2):193-201.