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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 847 records · Page 47
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Hepatic Arterial Embolization Using Cone Beam CT with Tumor Feeding Vessel Detection Software: Impact on Hepatocellular Carcinoma Response

PurposeDedicated tumor feeding vessel detection software (TFVDS) using cone beam CT has shown a higher sensitivity to detect tumor feeding vessels during hepatic arterial embolization (HAE) of hepatocellular carcinoma (HCC) compared to 2D imaging. Our primary hypothesis was that HCC tumors treated with HAE guided by a TFVDS would show more complete response (CR) than when treated with 2D imaging alone. Secondary analysis of the impact on X-ray exposure was performed.Materials and MethodsNineteen males and 8 females (median age: 69 year, 46–85) with 44 tumors (median size: 38 mm, 6–100) treated with selective HAE between January 2013 and December 2014 were included. Exclusion criteria were: extra-hepatic supply, >4 tumors, tumor size >10 cm, and adjunctive local therapy. Baseline patient and procedure characteristics were reviewed. Differences in CR per modified Response Evaluation Criteria in Solid Tumors were assessed by univariate and multivariate analyses for tumor size, number, location, particles size, and use of TFVDS.ResultsMedian imaging follow-up was 20.1 months (2–33). Use of TFVDS (13 patients, 19 tumors) was the only factor predictive of CR (OR = 3.85 [CI95%: 1.09, 13.67], p = 0.04) on univariate analysis but not on multivariate analysis (OR = 3.26 [0.87, 12.23], p = 0.08). A higher rate of CR was observed for HAE using TFVDS guidance versus 2D imaging alone (68.4%, 13–19, vs. 36%, 9–25, p = 0.03). Median dose area product was lower when TFVDS was used (149.7 Gy.cm{sup 2}, 38–365, vs. 227.8 Gy.cm{sup 2}, 85.3–468.6, p = 0.05).ConclusionsHCC embolized with TFVDS may result in improved local tumor response without increasing the dose exposure.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

Multipath Curved Planar Reformations of Peripheral CT Angiography: Diagnostic Accuracy and Time Efficiency

ObjectivesTo compare diagnostic performance and time efficiency between 3D multipath curved planar reformations (mpCPRs) and axial images of CT angiography for the pre-interventional assessment of peripheral arterial disease (PAD), with digital subtraction angiography as the standard of reference.MethodsForty patients (10 females, mean age 72 years), referred to CTA prior to endovascular treatment of PAD, were prospectively included and underwent peripheral CT angiography. A semiautomated toolbox was used to render mpCPRs. Twenty-one arterial segments were defined in each leg; for each segment, the presence of stenosis > 70% was assessed on mpCPRs and axial images by two readers, independently, with digital subtraction angiography as gold standard.ResultsBoth readers reached lower sensitivity (Reader 1: 91 vs. 94%, p = 0.08; Reader 2: 89 vs. 93%, p = 0.03) but significantly higher specificity (Reader 1: 94 vs. 89%, p < 0.01; Reader 2: 96 vs. 95%, p = 0.01) with mpCPRs than with axial images. Reader 1 achieved significantly higher accuracy with mpCPRs (93 vs. 91%, p = 0.02), and Reader 2 had similar overall accuracy in both evaluations (94 vs. 94%, p = 0.96). Both readers read mpCPRs significantly faster than axial images (Reader 1: 5′45″ based on mpCPRs vs. 7′40″ based on axial images; Reader 2: 4′41″ based on mpCPRs vs. 6′57″ based on axial images; p < 0.01).ConclusionsmpCPRs are a promising 3D reformation technique that facilitates a fast assessment of PAD with high diagnostic accuracy.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

Fibrolamellar Hepatocellular Carcinoma: Treatment with Yttrium-90 and Subsequent Surgical Resection

We describe a 52-year-old female patient who presented with a 9.5-cm fibrolamellar hepatocellular carcinoma (FL-HCC). The patient was initially unsuitable for surgical resection and therefore underwent transarterial chemoembolization followed by selective internal radiation therapy (SIRT) with Yttrium-90 to downsize the tumour. Following SIRT, the tumour decreased in volume from 350 to 20 cm{sup 3} allowing curative (R0) resection with an extended left hepatectomy and reconstruction of IVC. This is the first reported case of FL-HCC treated with SIRT in which, due to the good SIRT response, the patient was downsized to allow curative resection.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

Carbon dioxide Angiography-Guided Renal-Related Interventions in Patients with Takayasu Arteritis and Renal Insufficiency

BackgroundUse of iodinated contrast agents for angiography in patients with renal insufficiency risks further deterioration of renal function and its adverse sequelae.ObjectiveTo study the effectiveness and safety of carbon dioxide (CO{sub 2}) angiography in guiding percutaneous renal-related interventions in patients with Takayasu arteritis and renal insufficiency.MethodsData on CO{sub 2} angiography-guided interventions were obtained from a 23-year database of 692 Takayasu arteritis patients who underwent percutaneous interventions and were analyzed retrospectively. Follow-up data were also obtained. The CO{sub 2} angiography system used was developed in-house and was pressure-driven.ResultsSeven patients (6 female, age 16–59 years, baseline serum creatinine 1.62–4.55 mg/dl, estimated glomerular filtration rate 12.2–36.9 ml/min/1.73 m{sup 2}) underwent CO{sub 2} angiography-guided interventions: five underwent angioplasty or stenting to treat six stenotic/occluded renal arteries, one underwent extensive endovascular repair for spontaneous focal abdominal aortic dissection with false lumen aneurysm and aorto-iliac true lumen narrowing, and one underwent balloon dilatation of previously deployed aortic stents used to treat aortic occlusion at two levels. Follow-up (median 5 years, range 2 months–16 years) was obtained in all patients. All the procedures were successful and resulted in relief of symptoms, better blood pressure control, improvement in left ventricular systolic function and recovery or stabilization of renal function. There were no early or late complications related to CO{sub 2} angiography. Three renal lesions that had restenosis at follow-up were managed successfully by repeat intervention.ConclusionCO{sub 2} angiography-guided renal-related interventions are effective and safe in patients with Takayasu arteritis and renal insufficiency; they significantly improve the care of such patients.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

Custom-Made Endograft for Endovascular Repair of Thoraco-Abdominal Aneurysm and Type B Dissection: Single-Centre Experience

AimsTo report a series of patients treated with the Jotec custom-made endograft for thoraco-abdominal aneurysms and dissections and identify predictive factors for re-intervention.MethodsWe retrospectively analysed 49 patients unsuitable for surgery, treated between 2011 and 2017 (71.3 ± 9.5 years; 15 females). Indications included Crawford type 4 aneurysm in 25 patients, type 3 in 13, type 2 in 4, type 1 in 2 and chronic aneurysmal dilatation of the false lumen following dissection in 5 cases. Mean aneurysm diameter was 58.7 ± 8.4 mm. The study aims were to assess procedural success, complications rate, mortality and long-term follow-up. We also analysed factors that predicted the need for re-intervention.ResultsThe endograft was successfully deployed in all patients, catheterization of the fenestration and/or branches was achieved in 152/156 (97.4%) vessels. Early complications occurred in 10 patients (3 paraplegia, 3 haemorrhages, pancreatitis, aortic rupture, iliac artery rupture, 2 strokes). Thirty-day mortality was 10.2% and 180-day mortality 14.3%; two non procedure related deaths occurred. Mean follow-up was 23.6 ± 29.9 months [range 1–80]. No patients needed surgical explantation or developed significant renal impairment. Endoleak rate was 34.6% and re-intervention rate 9.7%. The aneurysm sac reduced or was stable in 36/49, and enlarged in 9/49 patients prompting re-intervention. Primary, primary-assisted and secondary patency of fenestrations/branches at 80 months was 90, 96 and 100%. Re-intervention was required more frequently in braches than in fenestrations, most commonly the external type branches.ConclusionsThe results of the Jotec endograft are comparable to other devices, with acceptable complication and re-intervention rates. Fenestration and inner-branch should be preferred due to lower re-intervention rates.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

Transarterial Radioembolization Following Chemoembolization for Unresectable Hepatocellular Carcinoma: Response Based on Apparent Diffusion Coefficient Change is an Independent Predictor for Survival

PurposeTo evaluate whether response based on contrast-enhanced magnetic resonance imaging (MRI) and apparent diffusion coefficient (ADC) change at diffusion-weighted MRI after transarterial radioembolization (TARE) can predict survival, in patients with prior transarterial chemoembolization with drug-eluting beads (DEB-TACE) for hepatocellular carcinoma (HCC).MethodsWe identified all patients who received DEB-TACE prior to TARE for HCC between 2007 and 2016. Response on MRI was determined by modified RECIST (mRECIST) and ADC change relative to pre-TARE imaging (ADCratio). Kaplan–Meier and log-rank tests were used to correlate the response/disease and treatment variables to overall survival. Multivariable Cox regression models were used to correct for confounders.ResultsA total of 29 consecutive patients were included. Univariable analysis showed that response determined by mRECIST was a nonsignificant predictor of survival (p = 0.057), and response determined by ADCratio was a significant predictor of survival (p = 0.011). Number of prior DEB-TACE procedures (p = 0.037), female gender (p < 0.001) and BCLC C (p = 0.03) were related to worse survival. The number of prior DEB-TACE procedure was significantly higher in non-responders determined by ADCratio (p = 0.028). Multivariable analyses showed that response based on ADCratio was an independent predictor of survival (p = 0.041).ConclusionADCratio following TARE is an independent predictor for survival in patients who previously underwent DEB-TACE for HCC.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

Transcatheter Arterial Embolization for Postoperative Bleeding Following Abdominal Surgery

PurposeWe aimed to estimate the usefulness of transcatheter arterial embolization (TAE) in patients with postoperative abdominal hemorrhage and to evaluate the effects of pancreatic fistula on clinical outcomes and angiographic findings.Materials and MethodsWe enrolled 22 patients (20 males and 2 females; mean age 63 years; range 25–86 years), who underwent transarterial angiography for postoperative hemorrhage after abdominal surgery. This group corresponded to 28 procedures. Technical and clinical success rates were calculated, and clinical findings and outcomes were compared between patients with and without a pancreatic fistula.ResultsPre-interventional CT was performed in all patients before first angiography, and the location of the bleeding was identified in all but one patient. Active arterial bleeding, identified by extravasation of contrast agent (n = 12), pseudoaneurysm formation (n = 12), and arterial wall irregularity (n = 2) were detected in 28 angiographic procedures, and embolization was performed in 26 instances. Various embolization techniques such as isolation, packing, embolization, and stentgraft implantation were performed. The technical and clinical success rates were 96% (25/26 procedures) and 82% (18/22 patients), respectively. In hemodynamically unstable patients (shock index: heart rate/systolic blood pressure > 1), a 92% (12/13 cases) technical success rate was achieved. There were no significant differences in any evaluated parameters between patients with and without pancreatic fistula.ConclusionTAE is a safe and effective for treating postoperative hemorrhage even in patients with hemodynamic instability and pancreatic fistula. Additionally, pre-interventional CT is useful for effective, consecutive interventions.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Rectal Venous Malformation Treated by Superior Rectal Artery Embolization

A 25-year-old female was referred to the Interventional Radiology Department for investigation and treatment of a rectal venous malformation (RVM) causing large recurrent episodes of rectal bleeding and chronic anaemia. Magnetic resonance imaging (MRI) demonstrated a large venous malformation affecting the rectum, lower pelvis and left thigh. After three failed attempts at injection foam sclerotherapy using fluoroscopic colonoscopy, a multidisciplinary team proposed an embolization procedure of the arterial inflow to the venous malformation. Following discussion with the patient, embolization of the superior rectal arteries was undertaken with immediate on-table fluoroscopic improvement in the RVM. Post-treatment, a significant reduction in bleeding, was reported by day 10 with subsequent return to activities of daily living and full employment. Follow-up MRI at 1 year demonstrated significant reduction in bowel-wall thickening.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Radiofrequency Wire Recanalization of Chronically Occluded Venous Stents: A Retrospective, Single-Center Experience in 15 Patients

Introduction: Chronically occluded venous stents may be difficult to salvage, necessitating multiple approaches and adjunctive techniques. Radiofrequency wires have been used to cross chronic obstructions in a variety of settings. Herein, radiofrequency wire recanalization (RFWR) of chronically occluded venous stents is presented. Materials and Methods: Fifteen patients (8 males; 7 females) aged 23–74 years (median 42 years) underwent prior venous stenting in the setting of venous occlusions. Seven had an underlying coagulopathy, three had May–Thurner syndrome, three had provoked deep venous thrombosis, one had a dialysis fistula, and one had pacer leads in situ. All indwelling venous stents were chronically occluded and symptomatic. Out of 15 patients, 13 (87%) had iliocaval venous stents, while two (13%) had superior vena cava and/or upper extremity venous stents. After failing conventional and blunt recanalization techniques, RFWR was performed to traverse the chronic occlusions. Technical success and complications were recorded. Results: Fifteen patients underwent 19 procedures. Twelve patients underwent one procedure, two patients had two procedures, and one patient had three procedures. RFWR alone was used in 12/19 (63%) procedures, while 7/19 (37%) required adjunctive sharp recanalization techniques. Technical success or crossing of the occlusion with flow restoration through the occluded segments was achieved in 17/19 (89%). One major and one minor complication occurred. Conclusion: Radiofrequency wire recanalization is an effective adjunct to revise chronically occluded venous stents, potentially increasing procedural success in challenging cases.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Hydrodissection of the Retrohepatic Space: A Technique to Physically Separate a Liver Tumour from the Inferior Vena Cava and the Ostia of the Hepatic Veins

Objective: To report a technique of percutaneous retrohepatic hydrodissection, highlighting its potential to physically separate liver tumours from the inferior vena cava (IVC) and the ostia of the hepatic veins (HV). Materials and Methods: Between December 2017 and April 2018, hydrodissection of the retrohepatic IVC was performed in 5 patients (5 females; mean age 64.5 years) undergoing percutaneous ablation of 5 liver metastases (mean size: 3.6 cm) located adjacent to the IVC. Number of hydrodissection needles, volume of hydrodissection, separation of tumour/liver parenchyma from IVC/HV post-hydrodissection; technical success of ablation; and complications were tabulated. Results: Two to three 22G spinal needles were required per case for adequate dissection. Mean volume to obtain sufficient hydrodissection was 410 ml on average. Physical separation of the IVC and tumour/hepatic parenchyma was successful in all cases, by 9 mm on average (range 5–12 mm). It also leaded to physical separation of the ostia of the right and middle HV in all cases. There was no early or delayed complication, notably no venous thrombosis in the post-operative period. All lesions but one were completely ablated after one session at 3-month follow-up. The patient with residual tumour was successfully retreated. Conclusion: Retrohepatic hydrodissection is a feasible technique to separate a tumour from the IVC and/or ostia of the HV. This could potentially limit the heat-sink effect/reduce the risk of thrombosis. Larger follow-up studies are required to assess efficacy on a long-term basis.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Lymphangiography and Post-lymphangiographic Multidetector CT for Preclinical Lymphatic Interventions in a Rabbit Model

Purpose: To describe the feasibility of lymphangiography and the visibility of the lymphatic system using post-lymphangiographic multidetector CT (MDCT) for preclinical lymphatic interventions in a rabbit model. Materials and Methods: Lymphangiography via the popliteal lymph node or vessel after surgical exposure was performed, using six healthy female Japanese White rabbits. Lipiodol was manually injected for lymphangiography. Post-lymphangiographic MDCT examinations were performed in all rabbits. The dataset images were subjected to image processing analysis utilizing the three-dimensional maximum intensity projection technique. Three reviewers evaluated the degree of depiction of the lymphatic system using a four-point visual score (1, poor; 2, fair; 3, good; 4, excellent). The distance between the body surface and cisterna chyli was measured on post-lymphangiographic MDCT axial image. Results: Lymphangiography was successfully performed in all rabbits. The popliteal lymph node was detectable in 90%. The visualization of lymphatic system via the popliteal node was achieved in 89%. Mean visual scores of > 3.0 were realized by the right femoral lymphatic vessel, left femoral lymphatic vessel, left iliac lymphatic vessel, left lumbar lymphatic trunks and cisterna chyli, whereas mean visual scores of < 3.0 were yielded by the right iliac lymphatic vessel, right lumbar lymphatic trunks and thoracic duct. The distance between the body surface and cisterna chyli on post-lymphangiographic MDCT axial images was 4.33 ± 0.14 cm. Conclusion: Lymphangiography is feasible, and the visibility of the lymphatic system on post-lymphangiographic MDCT in a rabbit model provides enough information for interventional radiologists to perform preclinical lymphatic interventions.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Image-Guided Percutaneous Bleomycin and Bevacizumab Sclerotherapy of Orbital Lymphatic Malformations in Children

Purpose: To evaluate the effectiveness and safety of image-guided percutaneous sclerotherapy using bleomycin for macrocystic and bevacizumab (Avastin™) for microcystic orbital lymphatic malformations in children. Materials and Methods: Between October 2015 and July 2018, we prospectively evaluated 10 pediatric patients who presented clinically and radiologically with lymphatic malformations and were treated with percutaneous sclerotherapy. Patients with venous malformations were excluded. Eight females and two males with ages ranging from 3 to 17 years (mean: 8.8, SD: 4.9) were included. Guided with ultrasound and fluoroscopy, macrocysts were treated with bleomycin instillation. For microcystic components in three patients, bevacizumab was injected intralesional. All patients underwent ultrasound and non-contrast MRI to evaluate response to treatment after 6 weeks. Results: The malformations were macrocystic in seven patients and complex (macro/microcystic) in three. Twenty sclerotherapy sessions were performed, (range: 1–3 sessions, mean: 2, SD: 0.8). Clinically, there was a significant reduction in the proptosis after treatment (P = 0.007) and dystopia (P = 0.018). The local radiological response showed a reduction in the maximum lesions diameters and volumes after treatment (P = 0.005 and 0.005, respectively). Two of the three patients treated with bevacizumab showed a reduction in the lesions volumes by 90.4% and 63.4%, respectively, whereas one patient did not show volume reduction. Transient periorbital edema and ecchymosis occurred following the procedure with no major complications encountered. Follow-up ranged from 9–33 months, mean: 20.3, SD: 7.4. Conclusion: Bleomycin sclerotherapy is a safe and effective treatment for orbital macrocystic lymphatic malformations. Further use of bevacizumab for microcystic lesions in a larger series is required to outline its efficacy and safety.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Transgraft sac Embolization Combined with Graft Reinforcement for Refractory Mixed-Type Endoleak

An 80-year-old female underwent EVAR 4 years ago. She presented type II endoleak with sac expansion from 68 to 80 mm during 3-year follow-up after EVAR. Although she underwent translumbar percutaneous sac embolization, the AAA sac continued to enlarge, suggesting mixed-type endoleak including type I, II, and III. Transgraft direct sac angiography revealed endoleak cavity without demonstrable feeding vessel. Transgraft sac embolization using n-butyl cyanoacrylate and graft reinforcement was performed concurrently, without complications. The graft reinforcement consisted of graft extension for eliminating occult type I endoleak, and relining for eliminating occult type III endoleak. Six months after the procedure, CT showed no signs of sac expansion. Transgraft sac embolization combined with graft reinforcement is one of the available options for persistent and refractory mixed-type endoleak.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Percutaneous Bronchial Embolization to Treat Intractable Bronchobiliary Fistula

Sixty-four-year-old female who underwent hemi-hepatectomy for intrahepatic cholangiocarcinoma a year ago presented with biliary sputum, cough and fever. Cross-sectional imaging showed a recurred tumor involving right diaphragmatic area and an abscess formation in liver dome with adjacent right lower lobe of lung. Percutaneous transhepatic biliary drainage and percutaneous drainage of lung abscess were performed. Tubogram showed connections between the lung abscess cavity and multiple distal bronchi, suggesting bronchobiliary fistulas. Two weeks of drainage treatment did not relieve symptoms. We successfully treated intractable bronchobiliary fistula via image-guided percutaneous access to closest distal bronchi near abscess with subsequent tandem placement of vascular plugs.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

The Role of a Curved Electrode with Controllable Direction in the Radiofrequency Ablation of Liver Tumors Behind Large Vessels

Purpose: To investigate the role of a novel curved radiofrequency ablation (RFA) electrode with controllable direction in the ablation of tumors behind large hepatic vessels in ex vivo bovine and in vivo canine liver experiments. Materials and Methods: Approval from the institutional animal care and use committee was obtained. In ex vivo experiments, conventional multi-tines expandable electrodes, conventional monopolar straight electrodes and novel curved electrodes were used in the ablation of the bovine liver (n = 90). The ablated area, parallel axis, vertical axis and shape of different electrodes were compared. Then, 24 beagle dogs (10 months old, female) were used for in vivo experiments. Visual tumor targets deeply located in the portal vein were established, and ultrasound-guided liver ablation was performed with different electrodes. The ablation range, target coverage rate, percentage of normal tissue injury and damage to adjacent vessels were evaluated. The Kruskal–Wallis test and the Chi-squared test were used for statistical analysis. Results: For the ex vivo study with a 3-cm electrode, the ablation area of the multi-tines expandable electrode group (7.14 ± 0.16 cm{sup 2}) was significantly larger than that of the novel curved electrode group (5.01 ± 0.30 cm{sup 2}, P < 0.001) and the monopolar straight electrode group (5.43 ± 0.15 cm{sup 2}, P < 0.001). The results obtained with the 4-cm electrode in the three groups were in accordance with those of the 3-cm electrode. In vivo, the normal tissue damage area of the novel curved electrode group was smaller than that of the multi-tines expandable electrode group (1.10 ± 0.18 cm{sup 2} vs. 4.00 ± 0.18 cm{sup 2}, P < 0.001). The target coverage rate of the novel curved electrode group was better than that of the monopolar straight electrode group (100% vs. 80.86 ± 1.68%, P < 0.001). The hematoxylin and eosin (H&E) and TUNEL staining results showed that the ablation necrosis area was adjacent to large vessels, but the vascular wall was not significantly damaged in the novel curved electrode group. Conclusion: Our preliminary results showed that the novel curved RFA electrode with controllable direction could achieve accurate ablation for tumors behind large hepatic vessels, with a better target coverage rate and less damage to normal tissue, than conventional multi-tines expandable electrodes and monopolar straight electrodes.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Endovascular Recanalization of Thromboangiitis Obliterans (Buerger’s Disease) in Twenty-Eight Consecutive Patients and Combined Antegrade–Retrograde Intervention in Eight Patients

Purpose: The aim of the study was to evaluate the technical success of the procedure and the clinical efficacy of treatment in patients with thromboangiitis obliterans (TAO) (Buerger’s disease) based on a change in the Rutherford classification. Materials and Methods: A total of 28 consecutive patients (26 males, 2 females, mean age 43.3 ± 5.32 years) underwent endovascular recanalization with a diagnosis of TAO, between April 2015 and July 2018. After unsuccessful attempts using the antegrade approach, retrograde approaches were used in 8 patients under ultrasound guidance. Clinical follow-up was routinely performed at 1-month, 3-month, 6-month, and 1-year intervals. Results: A total of 28 TAO patients underwent 40 procedures in 32 limbs. Technical success was achieved in 28 of the 32 limbs (87.5%). In total, 45 of 59 (76.2%) below the knee arteries were treated successfully. One major amputation was performed, providing a 96.8% rate for limb salvage both at 12 and 24 months. Amputation-free survival estimated by Kaplan–Meier analysis was 84% at 12 and 24 months. Primary patency rates at 12, 24, and 36 months were 84%, 78%, and 75%, respectively. Secondary patency rates were 87.5% both at 12 and 24 months. Conclusion: Endovascular treatment is a technically feasible and potentially effective treatment modality for Buerger’s disease. Combined antegrade and retrograde interventions in TAO patients may improve technical success and clinical recovery, especially in cases where the antegrade approach has failed.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Percutaneous Cryoablation of Stage T1b Renal Cell Carcinoma: Safety, Technical Results, and Clinical Outcomes

Purpose: The use of percutaneous cryoablation for T1b (4.1–7.0 cm) renal cell carcinoma, has not yet been widely adopted. The purpose of this study was to describe our experience in the cryoablation of stage T1b tumors with an emphasis on safety, technical results, and clinical outcomes. Materials and Methods: A retrospective review of hospital records identified 37 patients who underwent cryoablation for T1b lesions from 2008 to 2018. Patient demographics, comorbidities, tumor characteristics, technical parameters, and outcomes were recorded and analyzed. Recurrence-free, overall, and cancer-specific survival rates were estimated using the Kaplan–Meier method. Results: Thirty-seven patients (22 males, 15 females; mean age 66.5 ± 11.3) with 37 T1b tumors (mean diameter 47.3 ± 6.3 mm) were included. A median of 3 probes were used (range: 1–7). Angio-embolization was used in 3/37 (8.1%) and 2/37 patients (5.4%) required hydrodissection. The mean number of total cryoablation procedures for each patient was 1.5 (median 1; range: 1–4). Technical success was achieved in 88.2% of patients. Recurrence-free survival was 96.5%, 86.1%, and 62.6% at 1, 2, and 3 years respectively. Cancer-specific survival was 100% at 1, 2, and 3 years respectively. Overall survival was 96.7%, 91.8%, and 77.6% at 1, 2, and 3 years respectively. Complications classified as CIRSE grade 2 or higher occurred in 6/37 (16.2%) patients. Conclusion: T1b cryoablation is associated with high rates of technical success, excellent cancer-specific survival, and an acceptable safety profile. Level of Evidence: Level 4, Case Series.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

Comparison of neutron organ and effective dose coefficients for PIMAL stylized phantom in bent postures in standard irradiation geometries

Neutron dose coefficients for standard irradiation geometries have been reported in International Commission on Radiological Protection (ICRP) Publication 116 for the ICRP Publication 110 adult reference phantoms. In the present paper, organ and effective dose coefficients have been calculated for a receptor in both upright and articulated (bent) postures representing more realistic working postures exposed to a mono-energetic neutron radiation field. This work builds upon prior work by Dewji and co-workers comparing upright and bent postures for exposure to mono-energetic photon fields. Simulations were conducted using the Oak Ridge National Laboratory’s articulated stylized adult phantom, “Phantom wIth Moving Arms and Legs” (PIMAL) software package, and the Monte Carlo N-Particle (MCNP) version 6.1.1 radiation transport code. Organ doses were compared for the upright and bent (45° and 90°) phantom postures for neutron energies ranging from 1 × 10 -9 to 20 MeV for the ICRP Publication 116 external exposure geometries—antero-posterior (AP), postero-anterior (PA), and left and right lateral (LLAT, RLAT). Using both male and female phantoms, effective dose coefficients were computed using ICRP Publication 103 methodology. The resulting coefficients for articulated phantoms were compared to those of the upright phantom. Computed organ and effective dose coefficients are discussed as a function of neutron energy, phantom posture, and source irradiation geometry. For example, it is shown here that for the AP and PA irradiation geometries, the differences in the organ coefficients between the upright and bent posture become more pronounced with increasing bending angle. In the AP geometry, the brain dose coefficients are expectedly higher in the bent postures than in the upright posture, while all other organs have lower dose coefficients, with the thyroid showing the greatest difference. Finally and overall, the effective dose estimated for the upright phantom is more conservative than that for the articulated phantom, which may have ramifications in the estimation or reconstruction of radiation doses.

61 RADIATION PROTECTION AND DOSIMETRY↗