Genicular Artery Embolization for Treatment of Symptomatic Knee Osteoarthritis - Two Year Outcome Data.

PURPOSE: To report the 24-month outcomes and subgroup analysis evaluating the safety and effectiveness of the genicular artery embolization (GAE) for the treatment of symptomatic knee osteoarthritis (OA). MATERIALS AND METHODS: Forty participants with symptomatic moderate to severe knee OA from a single-center, single-arm prospective trial of GAE were included in this study. Abnormal genicular artery neovascularity was identified at the subject's focal knee pain with digital subtraction angiography and cone-beam computed tomography. Embolization was performed with 100-µm microspheres. The primary end point was treatment effectiveness as measured by sustained improvement in OA symptoms at 24 months, quantified using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Treatment success was defined as ≥50% decrease in WOMAC relative to baseline. Clinical outcomes were assessed with mean age of 66.0 ± 8.1 years and BMI of 30.1 ± 6.2 kg/m2. RESULTS: Two of the forty (5.0%) patients were lost to follow up. Overall, 18 of 38 (47.4%) patients demonstrated ≥50% reduction in WOMAC at 24 months. In the subset of patients with initial clinical success at 12 months, 18 of 25 (72.0%) reported sustained clinical success at 24 months. Seven of 25 (28.0%) had symptom recurrence between 12 and 24 months and were determined to be clinical failures. All treatment-related adverse events occurred within 12 months following GAE, without additional events after 12 months. CONCLUSION: GAE is effective in achieving sustained symptom relief related to moderate to severe knee OA for up to 24 months with an acceptable safety profile.

Society of Interventional Radiology Research Reporting Standards for Genicular Artery Embolization.

Genicular artery embolization (GAE) is an emerging, minimally invasive therapy to address the global burden of knee osteoarthritis (OA) and the unmet needs for medically refractory disease. Although total knee arthroplasty has been a standard intervention for severe cases, GAE is developing into a promising alternative, particularly for patients ineligible for or unwilling to undergo surgery. GAE targets the inflammatory cascade underlying OA pathophysiology by arresting neoangiogenesis and preventing pathological neoinnervation, offering potential pain relief. Although early studies have established safety and short-term effectiveness, ensuing studies are needed to validate long-term safety, durability, and comparative effectiveness and to optimize patient selection, embolic agent selection, and administration techniques. Standardized reporting guidelines are therefore essential to enhance transparency and reproducibility across clinical trials, facilitating data aggregation and comparison. This Society of Interventional Radiology (SIR)-endorsed reporting standards consensus document provides a framework to harmonize future research efforts and to improve the interpretation of outcomes.

Clinical, dosimetric, and reporting considerations for Y-90 glass microspheres in hepatocellular carcinoma: updated 2022 recommendations from an international multidisciplinary working group.

PURPOSE: In light of recently published clinical reports and trials, the TheraSphere Global Dosimetry Steering Committee (DSC) reconvened to review new data and to update previously published clinical and dosimetric recommendations for the treatment of hepatocellular carcinoma (HCC). METHODS: The TheraSphere Global DSC is comprised of health care providers across multiple disciplines involved in the treatment of HCC with yttrium-90 (Y-90) glass microsphere-based transarterial radioembolization (TARE). Literature published between January 2019 and September 2021 was reviewed, discussed, and adjudicated by the Delphi method. Recommendations included in this updated document incorporate both the results of the literature review and the expert opinion and experience of members of the committee. RESULTS: Committee discussion and consensus led to the expansion of recommendations to apply to five common clinical scenarios in patients with HCC to support more individualized efficacious treatment with Y-90 glass microspheres. Existing clinical scenarios were updated to reflect recent developments in dosimetry approaches and broader treatment paradigms evolving for patients presenting with HCC. CONCLUSION: Updated consensus recommendations are provided to guide clinical and dosimetric approaches for the use of Y-90 glass microsphere TARE in HCC, accounting for disease presentation, tumor biology, and treatment intent.

Added Value of Cone-Beam CT to Identify Arterial Supply during Genicular Artery Embolization for Knee Osteoarthritis.

PURPOSE: To evaluate if the addition of cone-beam computed tomography (CT) to digital subtraction angiography (DSA) improves the identification of the genicular arteries during genicular artery embolization (GAE) for knee pain secondary to osteoarthritis (OA). MATERIALS AND METHODS: This single-center study retrospectively analyzed 222 patients who underwent GAE for painful knee OA between May 2018 and April 2022. Intraprocedural cone-beam CT and DSA images were reviewed independently by 2 sets of interventional radiologists. DSA was performed for all patients. Technically adequate cone-beam CT was available for 205 patients (92.3%). The presence of the genicular arteries identified by cone-beam CT and DSA was compared using Φ coefficients. Embolization targets identified by both cone-beam CT and DSA were evaluated against those identified by DSA alone. RESULTS: Genicular arteries with the highest concordance between cone-beam CT and DSA were the inferior lateral (196 vs 198; Φ = 0.3530; P < .0001), superior lateral (197 vs 200; Φ = 0.3060; P < .0001), and superior medial genicular (186 vs 161; Φ = 0.2836; P < .0001) arteries. Cone-beam CT demonstrated higher rates of detection of the inferior medial (195 vs 178; Φ = 0.04573; P = .5150) and median genicular arteries (200 vs 192; Φ = 0.04573; P = .5150). Meanwhile, genicular arteries less frequently identified by cone-beam CT were the descending genicular (197 vs 200; Φ = -0.03186; P = .6502), superior patellar (175 vs 184; Φ = 0.1332; P = .0569), and recurrent anterior tibial (156 vs 186; Φ = 0.01809; P = .7969) arteries. Cone-beam CT in combination with DSA identified 13.4% (372 vs 328) more targets compared to DSA alone. CONCLUSIONS: Based on the results of the current study, cone-beam CT serves as a valuable adjunct for visualizing the genicular arteries during GAE, and together with DSA, it identifies more potential embolization targets.

Yttrium-90 Radioembolization for the Treatment of Solitary, Unresectable HCC: The LEGACY Study.

BACKGROUND AND AIMS: Locoregional therapies, including yttrium-90 radioembolization, play an important role in the treatment of unresectable HCC. The aim of the LEGACY (Local radioEmbolization using Glass Microspheres for the Assessment of Tumor Control with Y-90) study was to evaluate objective response rate (ORR) and duration of response (DoR) in patients with solitary unresectable HCC treated with yttrium-90 glass microspheres. APPROACH AND RESULTS: LEGACY is a multicenter, single-arm, retrospective study conducted at three sites that included all eligible, consecutive patients with HCC treated with radioembolization between 2014 and 2017. Eligibility criteria included solitary HCC ≤ 8 cm, Child-Pugh A cirrhosis, and Eastern Cooperative Oncology Group performance status 0-1. Primary endpoints were ORR and DoR based on modified Response Evaluation Criteria in Solid Tumors in the treated area (localized), as evaluated by blinded, independent, central review. Radioembolization was performed with intent of ablative-level dosimetry in a selective fashion when possible. Overall survival was evaluated using Kaplan-Meier and multivariate Cox proportional hazards. Among the 162 patients included, 60.5% were Eastern Cooperative Oncology Group 0, and the median tumor size was 2.7 cm (range: 1-8) according to blinded, independent, central review. Radioembolization served as neoadjuvant therapy for transplantation or resection in 21.0% (34 of 162) and 6.8% (11 of 162) of patients, respectively, and as primary treatment for all others. Median follow-up time was 29.9 months by reverse Kaplan-Meier. ORR (best response) was 88.3% (CI: 82.4-92.4), with 62.2% (CI: 54.1-69.8) exhibiting a DoR ≥ 6 months. Three-year overall survival was 86.6% for all patients and 92.8% for those neoadjuvant patients with resected or transplanted liver. CONCLUSIONS: In this multicenter study of radioembolization, clinical meaningful response rates and prolonged DoR were observed in the treatment of unresectable, solitary HCC ≤ 8 cm.

Yttrium-90 radiation segmentectomy for hepatic metastases: A multi-institutional study of safety and efficacy.

BACKGROUND AND OBJECTIVES: This study assessed the outcomes of Yttrium-90 (90 Y) radiation segmentectomy for hepatic metastases unamenable to resection or ablation. MATERIALS AND METHODS: Over 6 years, 36 patients with 53 tumors underwent segmental radioembolization. Patients were not candidates for surgical resection or thermal ablation. Malignancies included metastases from colorectal cancer (31%), neuroendocrine tumors (28%), sarcoma (19%), and others (22%). Eighty-one percent of patients had undergone prior treatment with systemic chemotherapy. Ongoing systemic chemotherapy was continued. Toxicity, tumor response, tumor progression, and survival were assessed. RESULTS: The median tumor size was 3.6 cm (range 1.2-6.1 cm). Adverse event rates were low, with no hepatic-related Common Terminology Criteria for Adverse Events Grade 3 or 4 toxicity. Target tumor Response Evaluation Criteria in Solid Tumors disease control rate was 92% (28% partial response, 64% stable disease). For patients with enhancing tumors (n = 14), modified Response Evaluation Criteria in Solid Tumors target tumor objective response rate was 100%. During a median follow-up of 12 months, target tumor progression occurred in 28% of treated tumors. Overall survival was 96% and 83% at 6 and 12 months, respectively. CONCLUSIONS: 90 Y radiation segmentectomy for hepatic metastases demonstrates high rates of tumor control and minimal toxicity. Radiation segmentectomy should be considered for patients with metastatic hepatic malignancy who are not candidates for surgical resection.

Transarterial Yttrium-90 Radioembolization of Hepatocellular Carcinoma Perfused by the Cystic Artery: Multi-institutional Feasibility Study.

PURPOSE: To assess the safety and efficacy of transarterial yttrium-90 radioembolization via the cystic artery for patients with hepatocellular carcinoma (HCC) adjacent to the gallbladder with cystic artery supply. MATERIALS AND METHODS: This retrospective study included 17 patients treated at 4 institutions. Patients with HCC perfused by the cystic artery who received ablative-dose radioembolization were included. Median tumor size was 3.8 cm (range, 2.0-8.8 cm). Fourteen patients (82%) had Child-Pugh class A cirrhosis and 3 (18%) had class B cirrhosis. Adverse events, tumor response, and time to progression were analyzed. RESULTS: Median dose to the tissue perfused by the cystic artery was 340 Gy (range, 200-720 Gy). There were no occurrences of acute cholecystitis warranting invasive intervention. Four patients (24%) experienced transient right upper quadrant pain, with symptom resolution within 3 mo. Six patients (35%) exhibited gallbladder wall edema on follow-up imaging. Two (12%) and 0 grade 3/4 increases in alkaline phosphatase and bilirubin were observed, respectively. Follow-up imaging demonstrated complete response in 13 target tumors (76%) and partial response in 4 (24%). There were no cases of target tumor progression during a median follow-up of 9 mo (range, 3-72 mo). CONCLUSIONS: Direct infusion of 90Y microspheres via the cystic artery appears to have an acceptable safety profile, without resulting in acute cholecystitis warranting invasive intervention. In selected patients with HCC in whom other treatments may be contraindicated and the tumor is supplied via the cystic artery, treatment with selective ablative radioembolization can be considered.

Irreversible Electroporation for Hepatic Tumors: Protocol Standardization Using the Modified Delphi Technique.

PURPOSE: A consensus study of panelists was performed to provide a uniform protocol regarding (contra) indications, procedural parameters, perioperative care, and follow-up of irreversible electroporation (IRE) for the treatment of hepatic malignancies. MATERIALS AND METHODS: Interventional radiologists who had 2 or more publications on IRE, reporting at least 1 patient cohort in the field of hepatobiliary IRE, were recruited. The 8 panelists were asked to anonymously complete 3 iterative rounds of IRE-focused questionnaires to collect data according to a modified Delphi technique. Consensus was defined as having reached 80% or greater agreement. RESULTS: Panel members' response rates were 88%, 75%, and 88% in rounds 1, 2, and 3, respectively; consensus was reached on 124 of 136 items (91%). Percutaneous or intraoperative hepatic IRE should be considered for unresectable primary and secondary malignancies that are truly unsuitable for thermal ablation because of proximity to critical structures. Absolute contraindications are ventricular arrhythmias, cardiac stimulation devices, and congestive heart failure of New York Heart Association class 3 or higher. A metal stent outside the ablation zone should not be considered a contraindication. For the only commercially available IRE device, the recommended settings are an inter-electrode distance of 10-20 mm and an exposure length of 20 mm. After 10 test pulses, 90 treatment pulses of 1500 V/cm should be delivered continuously, with a pulse length of 70-90 µs. The first post-procedural follow-up should take place 1 month after IRE and thereafter every 3 months, using cross-sectional imaging plus tumor marker assessment. CONCLUSIONS: This article provides recommendations, created by a modified Delphi consensus study, regarding patient selection, workup, procedure, and follow-up of IRE treatment for hepatic malignancies.

Clinical and dosimetric considerations for Y90: recommendations from an international multidisciplinary working group.

The TheraSphere Global Dosimetry Steering Committee was formed in 2017 by BTG International to review existing data and address gaps in knowledge related to dosimetry. This committee is comprised of health care providers with diverse areas of expertise and perspectives on radiation dosimetry. The goal of these recommendations is to optimize glass microspheres radiation therapy for hepatocellular carcinoma while accounting for variables including disease presentation, tumour vascularity, liver function, and curative/palliative intent. The recommendations aim to unify glass microsphere users behind standardized dosimetry methodology that is simple, reproducible and supported by clinical data, with the overarching goal of improving clinical outcomes and advancing the knowledge of dosimetry.

A reality check in transradial access: a single-centre comparison of transradial and transfemoral access for abdominal and peripheral intervention.

OBJECTIVES: The purpose of this study was to describe a single institution's experience with transradial access (TRA) for angiographic interventions, and to compare technical success, complication rate and radiation dose of procedures performed with TRA to those performed with transfemoral access (TFA). METHODS: A retrospective cohort study of patients undergoing peripheral interventions via TRA or TFA from 2015 to 2017 was performed. The cohort comprised 33 patients undergoing 44 procedures via TRA and 37 patients undergoing 44 procedures via TFA. Outcome measures were technical success, access-related complications, fluoroscopy time and radiation exposure. Differences at p < 0.05 were considered to be statistically significant. RESULTS: Baseline characteristics were similar between patients who had procedures via TRA versus those who had procedures via TFA, including age, sex and body mass index. Technical success was achieved in 41/44 (93.2%) of procedures performed via TRA, compared to 44/44 (100%) of procedures performed via TFA (p = 0.241). There were three access-related complications (6.8%) when TRA was performed, compared to none when TFA was performed (p = 0.241). Fluoroscopy time was longer in procedures performed with TRA compared to those performed with TFA (27.3 vs 20.4, p = 0.033). Dose area product (DAP) did not differ with access site choice (p = 0.186). CONCLUSIONS: TRA is a safe and feasible alternative to TFA for a range of peripheral interventions. However, TRA must be performed with prudence as it is not without complications and is technically challenging, leading to longer fluoroscopy time. KEY POINTS: • Transradial access (TRA) is feasible in a variety of peripheral interventions, achieving success in 93.2% of cases. • Access-related complications are comparable between transfemoral access (TFA) and TRA (p = 0.241), but prudence must be taken during TRA as it could be technically challenging. • Procedures performed with TRA tend to have longer fluoroscopy time compared to those performed with TFA (p = 0.033), but the DAPs are comparable (p = 0.186).

Coil-Assisted Retrograde Transvenous Obliteration (CARTO): An Alternative Treatment Option for Refractory Hepatic Encephalopathy.

BACKGROUND: Overt hepatic encephalopathy (OHE) is a serious complication of liver dysfunction, which is associated with severe morbidity/mortality and healthcare resource utilization. OHE can be medically refractory due to spontaneous portosystemic shunts (SPSSs) and therefore a new treatment option for these SPSSs is critical. METHODS: This is a retrospective study of 43 patients with medically refractory OHE, who underwent CARTO (Coil-Assisted Retrograde Transvenous Obliteration) procedures between June 2012 and October 2016. The patient demographic characteristics, technical and clinical outcomes with an emphasis on HE improvement, and complications are reviewed and analyzed. RESULTS: The overall clinical success rate was 91% with a significant HE improvement. Eighty-one percent of patients had clinically significant improvement from OHE and 67% of patients had complete resolution of their HE symptoms during our follow-up period of 893 ± 585 days (range 36-1881 days, median 755.0 days). The median WH score improved from 3 (range 2-4) pre-CARTO to 1 (range 0-4) post-CARTO (p < 0.001). The median ammonia level significantly decreased from 134.5 pre-CARTO to 70.0 post-CARTO (p < 0.001) in 3 days. The overall mean survival was 1465.5 days (95% CI of 1243.0 and 1688.0 days). Only three patients had recurrent HE symptoms. There were 39.6% minor complication rate including new or worsened ascites and esophageal varices, and only 2.3% major complication rate requiring additional treatment (one patient with bleeding esophageal varices requiring treatment). No procedure-related death is noted. CONCLUSIONS: CARTO appears to be a safe and effective treatment option for refractory overt hepatic encephalopathy (OHE) due to spontaneous portosystemic shunts. CARTO could be an excellent addition to currently available treatment options for these patients.

Response and Overall Survival for Yttrium-90 Radioembolization of Hepatic Sarcoma: A Multicenter Retrospective Study.

PURPOSE: To evaluate the effectiveness and safety of yttrium-90 transarterial radioembolization (TARE) for the treatment of primary and metastatic soft tissue sarcoma (STS) of the liver. MATERIALS AND METHODS: A retrospective review of 39 patients with primary (n = 2) and metastatic (n = 37) hepatic STS treated with TARE at 4 institutions was performed. Fourteen STS subtypes were included, with leiomyosarcoma being the most common (51%). TARE with glass (22 patients) or resin (17 patients) microspheres was performed, with single lobe (17 patients) or bilobar treatment (22 patients) based on disease burden. Adverse events of treatment, overall survival (OS), and tumor response at 3, 6, and 12 months after TARE were assessed per the Response Evaluation Criteria in Solid Tumors. RESULTS: Fourteen patients demonstrated either partial or complete response to therapy, with an objective response rate of 36%. Thirty patients (77%) demonstrated disease control (DC)-either stable disease or response to treatment. Median OS was 30 months (95% confidence interval 12-43 months) for all patients. DC at 3 months was associated with an increased median OS (44 months) compared with progressive disease (PD) (7.5 months; P < .0001). Patients with DC at 6 months also demonstrated an increased median OS (38 months) compared to patients with PD (17 months; P = .0443). Substantial adverse events included 1 liver abscess, 1 gastric ulceration, and 1 pneumonitis. CONCLUSIONS: Patients with hepatic STS treated with TARE demonstrated a high rate of DC and a median OS of 30 months, which suggests a role for TARE in the palliation of hepatic STS.

Value of Antibiotic Prophylaxis for Percutaneous Gastrostomy: A Double-Blind Randomized Trial.

PURPOSE: To compare peristomal infection rates following percutaneous gastrostomy (PG) after a single dose of prophylactic antibiotics versus placebo and evaluate rates of peristomal infection in patients receiving concurrent antibiotics. MATERIALS AND METHODS: This single-center, randomized trial (2012-2016) enrolled 122 patients referred for image-guided PG; all enrolled patients completed the study. Of enrolled patients, 68 were randomly assigned to receive either antibiotics (n = 34) or placebo (n = 34) before PG placement. The remaining 54 patients were taking pre-existing antibiotics and were assigned to an observation arm. Stoma sites were assessed for signs of infection by a blinded evaluator at early (between 3-5 d and 7-10 d) and late (between 14-17 d and 28-30 d) time points after the procedure. The primary outcome was peristomal infection. RESULTS: Under intention-to-treat analysis, early infection rate was 11.8% (4/34 patients; 95% CI, 0.0%-9.4%) in the placebo arm and 0.0% (0/34 patients; 95% CI, 0.0%-8.4%) in the antibiotic arm (P = .057 for comparison of infections in the 2 arms). Under per-protocol analysis, early infection rate was 13.3% (4/30 patients; 95% CI, 4.4%-29.1%) in the placebo arm and 0.0% (0/32 patients; 95% CI, 0.0%-8.9%) in the antibiotic arm (P = .049). The number needed to treat to prevent 1 early infection was 8.5 and 7.5 from the 2 analyses, respectively. CONCLUSIONS: There is a trend toward reduction in rate of peristomal infection after PG when prophylactic antibiotics are administered.

Safety and Efficacy Outcomes of Embolization in Hepatic Sarcomas.

OBJECTIVE: The outcome for patients with unresectable hepatic sarcoma is poor with a median survival period of 12-16 months. The purpose of this study was to evaluate liver-directed transcatheter therapies for the treatment of hepatic sarcomas. MATERIALS AND METHODS: In a retrospective study, the cases of patients with primary and metastatic hepatic sarcoma treated by transcatheter embolization, chemoembolization, and 90Y radioembolization between 2004 and 2015 were identified. Response Evaluation Criteria in Solid Tumors version 1.1 response was assessed for the target tumor. Survival was assessed by means of Kaplan-Meier analysis. RESULTS: Twenty-eight patients (17 [61%] men, 11 [39%] women; median age, 47 years) were included. Eighteen patients were treated electively. Two of the electively treated patients underwent embolization; eight, chemoembolization; six, radioembolization; and two, a combination of transcatheter treatments. Treatment was well tolerated; only one patient had grade 3 hepatic toxicity. The objective response rate of the index tumor was 61%, and the median overall survival period was 26.7 months. Ten patients underwent emergency embolization to control acute hemorrhage from tumor rupture. The median overall survival periods were 611 days for the patients with ruptured gastrointestinal stromal tumors (GIST) (n = 3) and 19 days for the patients with ruptured angiosarcoma (n = 7). CONCLUSION: Liver-directed transcatheter therapies are safe and may have a role in the elective management of unresectable primary and metastatic liver sarcomas. Emergency embolization for ruptured GIST may be effective for stabilizing the patient's condition and allowing more definitive therapy in the future. However, emergency embolization has limited efficacy in treating patients with ruptured angiosarcoma, likely because of substantial venous bleeding at rupture and the aggressive behavior of this lesion.

Segmental Yttrium-90 Radioembolization versus Segmental Chemoembolization for Localized Hepatocellular Carcinoma: Results of a Single-Center, Retrospective, Propensity Score-Matched Study.

PURPOSE: To compare segmental radioembolization with segmental chemoembolization for localized, unresectable hepatocellular carcinoma (HCC) not amenable to ablation. MATERIALS AND METHODS: In a single-center, retrospective study (2010-2015), 101 patients with 132 tumors underwent segmental radioembolization, and 77 patients with 103 tumors underwent segmental doxorubicin-based drug-eluting embolic or conventional chemoembolization. Patients receiving chemoembolization had worse performance status (Eastern Cooperative Oncology Group 0, 76% vs 56%; P = .003) and Child-Pugh class (class A, 65% vs 52%; P = .053); patients receiving radioembolization had larger tumors (32 mm vs 26 mm; P < .001), more infiltrative tumors (23% vs 9%; P = .01), and more vascular invasion (18% vs 1%; P < .001). Toxicity, tumor response, tumor progression, and survival were compared. Analyses were weighted using a propensity score (PS). RESULTS: Toxicity rates were low, without significant differences. Index and overall complete response rates were 92% and 84% for radioembolization and 74% and 58% for chemoembolization (P = .001 and P < .001). Index tumor progression at 1 and 2 years was 8% and 15% in the radioembolization group and 30% and 42% in the chemoembolization group (P < .001). Median progression-free and overall survival were 564 days and 1,198 days in the radioembolization group and 271 days and 1,043 days in the chemoembolization group (PS-adjusted P = .002 and P = .35; censored by transplant PS-adjusted P < .001 and P = .064). CONCLUSIONS: Segmental radioembolization demonstrates higher complete response rates and local tumor control compared with segmental chemoembolization for HCC, with similar toxicity profiles. Superior progression-free survival was achieved.

Irreversible Electroporation in Patients with Hepatocellular Carcinoma: Immediate versus Delayed Findings at MR Imaging.

PURPOSE: To assess the postprocedure findings of irreversible electroporation (IRE) in patients with hepatocellular carcinoma (HCC) at magnetic resonance (MR) imaging. MATERIALS AND METHODS: This retrospective study was Institutional Review Board approved, and informed consent was waived. Twenty patients with HCC were treated with IRE over a 2.5-year period. The median patient age was 62 years, and 75% of patients had cirrhosis with a Child-Pugh score of A. The median tumor diameter was 2.0 cm (range, 1.0-3.3 cm). Contrast material-enhanced multiphase MR imaging was performed on postprocedure days 1 and 30 and every 90 days thereafter. Ablation zone sizes and signal intensities were compared between each time point for both T1- and T2-weighted images. Trends in signal intensity and tumor dimensions over time were quantified by using generalized linear models. RESULTS: MR imaging appearances of treated tumors include a zone of peripheral enhancement with centripetal filling on delayed contrast-enhanced images. Compared with postprocedure day 1, every 90 days there is a decrease of 28.9% (mean, axis) in the size of the enhancing ablation zone. Over time, there is a trend toward decreasing signal intensity in the peripheral ablation zone on both T2-weighted (P = .01) and contrast-enhanced T1-weighted (P < .08) images. Conversely, the tumor itself typically has increased signal intensity on the same sequences. CONCLUSION: IRE of HCC results in a large region of enhancement on immediate postprocedure MR images that, over time, involutes and is associated with decreasing signal intensity of the peripheral ablation zone. This phenomenon may represent resolution of the reversible penumbra.

Introduction to Cost Analysis in IR: Challenges and Opportunities.

Demonstration of value has become increasingly important in the current health care system. This review summarizes four of the most commonly used cost analysis methods relevant to IR that could be adopted to demonstrate the value of IR interventions: the cost minimization study, cost-effectiveness assessment, cost-utility analysis, and cost-benefit analysis. In addition, the issues of true cost versus hospital charges, modeling in cost studies, and sensitivity analysis are discussed.

Cone-Beam CT with Fluoroscopic Overlay Versus Conventional CT Guidance for Percutaneous Abdominopelvic Abscess Drain Placement.

PURPOSE: To compare technical success and procedure time for percutaneous abscess drain placement with fluoroscopic cone-beam computed tomography (CT) and two-axis needle guidance versus conventional CT guidance. MATERIALS AND METHODS: A total of 85 consecutive patients undergoing abdominopelvic abscess drain placement guided by fluoroscopic cone-beam CT or conventional CT were retrospectively reviewed over a 2-year period. Forty-three patients underwent drain placement with cone-beam CT using XperGuide navigation and 42 underwent placement with conventional 64-slice CT. Patient characteristics, median abscess size (6.8 cm vs 7.8 cm; P = .14), and depth to abscess (7.2 cm vs 7.7 cm; P = .88) were similar between groups. RESULTS: Technical success rates were 98% (42 of 43) in the cone-beam CT group and 100% (42 of 42) in the conventional CT group (P = .32), with a 10-F pigtail drainage catheter inserted in the majority of cases. There were no complications in either group. There was no significant difference in effective dose between groups (9.6 mSv vs 10.7 mSv; P = .30). Procedure times were significantly shorter in the cone-beam CT group (43 min vs 62 min; P = .02). In addition, during the study period, there was a gradual improvement in procedure time in the cone-beam CT group (50% reduction), whereas procedure time did not change for the conventional CT group. CONCLUSIONS: Cone-beam CT guidance appears to be equivalent to conventional CT guidance for drain placement into medium-sized abdominopelvic collections, yielding similar technical success rates and radiation doses, with the additional benefit of reduced procedure times.

Yttrium-90 Radioembolization as a Salvage Treatment following Chemoembolization for Hepatocellular Carcinoma.

PURPOSE: To determine safety and efficacy of yttrium-90 ((90)Y) transarterial radioembolization (TARE) in patients who have undergone chemoembolization for hepatocellular carcinoma. MATERIALS AND METHODS: A retrospective study identified 40 patients (median age 61 y; range, 44-84 y) who underwent (90)Y mapping angiography and had undergone ≥ one prior chemoembolizations. There were 4 (10%) patients in Barcelona Clinic Liver Cancer stage A, 7 (17.5%) in stage B, and 29 (72.5%) in stage C; 28 (70%) were Child-Pugh class A and 12 (30%) were class B. Median tumor diameter was 4.2 cm (range, 1-11.6 cm). The most common indications for changing to TARE were tumor progression (35/40; 86%) and development of portal vein thrombus (15/40; 37.5%). RESULTS: Of 40 patients, 29 (72.5%) underwent TARE; the most common reasons for not undergoing TARE were attenuated hepatic arteries (5/11), high pulmonary shunt (4/11), and poor arterial flow (2/11). Patients who underwent ≤ 4 chemoembolizations to the TARE target tended to be more likely to undergo TARE after mapping than patients who had > 4 chemoembolizations (P = .056). Most common grade ≥ 3 toxicities were fatigue (9/29; 31%) and biochemical alterations (bilirubin [3/29; 10.3%], albumin [4/29; 13.8%], aspartate aminotransferase [5/29; 17.2%]). Of 27 patients treated with TARE with follow-up, responses were 11 (41%) complete response, 5 (19%) partial response, 2 (7%) stable disease, and 9 (33%) progressive disease. Median progression-free survival and overall survival were 90 days and 257 days. CONCLUSIONS: TARE is safe and effective salvage therapy in patients after chemoembolization. In patients who have undergone > 4 chemoembolizations to the (90)Y target, feasibility of TARE tends to be decreased.