(p>0.1). The major complication (> grade 3) rate was 8.1% (3/37), with two major complications attributable to the proced- ure. One death was due to a pulmonary embolism unrelated to the ablation procedure. Transient severe hypertension (>260/120) was noted in 2 cases which was rapidly managed medication without sequale. No significant intra or postprocedural changes in blood pressure since pretreatment with doxazocin was imple- mented (N ¼ 8). Conclusions: CT-guided percutaneous cryoablation is a safe, effective and low morbidity alternative for patients with adrenal tumors. Transient hypertension is related only to residual viable adrenal tissue but can be safely managed. 3:27 PM Abstract No. 335 Machine learning–based radiomics improve post- ablation prognostication in patients with adrenal metastases D. Daye 1 , A. Tabari 1 , M. Caton 2 , N. Frenk 1 , F. Fintelmann 1 , M. Gee 1 , R. Uppot 1 ; 1 Massachusetts General Hospital, Boston, MA; 2 Brigham and Women’s Hospital, Boston, MA Purpose: Radiomics analysis is advantageous for the assessment of aspects of tumor biology not readily discernible to the human eye. The goal of this study is to assess the role of pre-ablation CT radiomics analysis in improving outcome prediction of patients who underwent ablation for adrenal metastases. Materials: In this IRB-approved retrospective study, we identified 21 patients with pre-ablation contrast-enhanced CT imaging who underwent percutaneous ablation for adrenal metastases. Patient survival was available for up to 108 months. Standard clinical prognostic variables were extracted from the medical record. Ad- renal tumors were identified on the pre-ablation axial CT series and manually segmented. A heterogeneity phenotype vector consisting of 30 quantitative radiomics features was extracted from each lesion. Cox regression analysis was used to assess for independent contribution of the extracted features to survival prediction. A linear support vector machine (SVM) machine learning technique was applied to the extracted data and to standard prognostic clinical variables, with 10-fold cross validation to avoid overfitting. ROC analysis and the area under the curve (AUC) were used to assess classification performance. Results: Mean overall patient survival was 35 months. Pre- ablation tumor entropy (HR>10; p ¼ 0.004), inverse order (HR>10; p ¼ 0.013), energy (HR>10; p ¼ 0.008) and standard deviation (HR<0.1; p ¼ 0.005) exhibited significant independent association with patient survival. 7 Laws texture features contributed independently to survival prediction (p<0.01). The trained SVM model based on standard clinical prognostic vari- ables resulted in an AUC of 0.68. An SVM model that includes radiomics features in addition to clinical variables resulted in improved model performance for survival prediction (AUC 0.93; p ¼ 0.024). Conclusions: Pre-ablation radiomics improves survival predic- tion in patients with adrenal metastases who undergo ablation by potentially adding tumor characteristics not currently captured by standard prognostic markers. Machine learning-based predictive models incorporating radiomics may improve prognostication in patients undergoing adrenal tumor ablation. 3:36 PM Abstract No. 336 MR/US fusion-guided ultra-focal gold nanoparticle directed photothermal ablation of prostate gland tumors: results in 9 patients (phase II trial) P. Shukla 1 , H. Anastos 2 , J. Winoker 2 , M. Carrick 2 , J. Sfakianos 2 , C. Knauer 3 , B. Taouli 2 , S. Lewis 4 , J. Schwartz 5 , A. Rastinehad 6 ; 1 Mount Sinai Hospital, The Icahn School of Medicine, New York, NY; 2 The Icahn School of Medicine at Mount Sinai, New York, NY; 3 Icahn School of Medicine at Mount Sinai, New York, NY; 4 Icahn School of Medicine at Mount Sinai Hospital, New York, NY; 5 Nanospectra Biosciences, Inc, Houston, TX; 6 Icahn School of Medicine at Mount Sinai Department of Urology, New York, NY Purpose: Gold nanoparticle (GNP) mediated laser ablation have been shown in vitro to be biocompatible and safe for the treatment of focal cancer. Herein, we report the first 9 cases in the world using GNP-directed focal laser ablation of prostate tumors using ultrasound (US) and MR/US fusion technology. Materials: All patients with elevated PSA and sub-centimeter lesions on MRI underwent MR/US fusion biopsy and had pa- thology proven prostate cancer. Patients underwent ultra-focal laser ablation of the tumors using GNP with MR/US fusion guidance. Following infusion of intravenous GNP on Day 0, trans-perineal laser catheters were placed into the prostate lesions for GNP excitation/tumor ablation under MR/US fusion guidance using an electromagnetic-tracked MR/US fusion device (Uro- Nav). At 48 hours post-ablation, the patient is imaged, followed by re-imaging and MR/US fusion-guided biopsy (FBx) at 3 months. All patient demographics, clinical variables, and com- plications were recorded. Results: To date, 9 patients (mean age: 69.4 years; range 59-80 years) have been enrolled in the trial. All patients were diagnosed with Gleason 6/7 prostate cancer using trans-perineal MR/US Fusion biopsy. All patients had a solitary lesion with mean tumor volume 0.73 mL (range, 0.6-1.87 cc). The area ablation appeared to cover the tumor on immediate postprocedure MRI in all 9 patients. No procedure related or short-term complications were observed. At the time of abstract submission, 6 patients had reached the 3-month follow-up period. Mean pretreatment PSA was 7.3 ng/mL (range, 5.5-12.4 ng/mL). Mean pose-treatment PSA was 3.9 ng/mL (range, 1.5-6.1 ng/mL). Three of six patients (50%) did not have any cancer detected on follow-up biopsy. Two of the Three patients had micro focus of Gleason 6 and the final patient was downgrade from Gleason 4+3 to 3+4. Conclusions: Recent trends toward less invasive image-guided therapies have been seen as investigators pursue focal targeted therapies. This report is the first in-man demonstration of MR/US- guided ultra-focal prostate ablation using laser activated gold nanoparticle for the treatment of sub-centimeter prostate cancer. 3:45 PM Abstract No. 337 Radiofrequency ablation of parathyroid adenomas to treat clinically significant hypercalcemia A. Khandelwal 1 , A. Kapoor 2 , R. Khandelwal 3 , D. Agarwal 3 , S. Gupta 3 , S. Baijal 4 ; 1 Medanta-The Medicity, Gurgaon, Haryana; 2 Medanta-The Medicity, S144 ▪ Wednesday Scientific Sessions ▪ JVIR WEDNESDAY: Scientific Sessions