Utility of pre-procedural [99mTc]TcMAA SPECT/CT Multicompartment Dosimetry for Treatment Planning of 90Y Glass microspheres in patients with Hepatocellular Carcinoma: comparison of anatomic versus [99mTc]TcMAA-based Segmentation.

PURPOSE: Pre-treatment [99mTc]TcMAA-based radioembolization treatment planning using multicompartment dosimetry involves the definition of the tumor and normal tissue compartments and calculation of the prescribed absorbed doses. The aim was to compare the real-world utility of anatomic and [99mTc]TcMAA-based segmentation of tumor and normal tissue compartments. MATERIALS AND METHODS: Included patients had HCC treated by glass [90Y]yttrium microspheres, ≥ 1 tumor, ≥ 3 cm diameter and [99mTc]TcMAA SPECT/CT imaging before treatment. Segmentation was performed retrospectively using dedicated dosimetry software: (1) anatomic (diagnostic CT/MRI-based), and (2) [99mTc]TcMAA threshold-based (i.e., using an activity-isocontour threshold). CT/MRI was co-registered with [99mTc]TcMAA SPECT/CT. Logistic regression and Cox regression, respectively, were used to evaluate relationships between total perfused tumor absorbed dose (TAD) and objective response rate (ORR) and overall survival (OS). In a subset-analysis pre- and post-treatment dosimetry were compared using Bland-Altman analysis and Pearson's correlation coefficient. RESULTS: A total of 209 patients were enrolled. Total perfused tumor and normal tissue volumes were larger when using anatomic versus [99mTc]TcMAA threshold segmentation, resulting in lower absorbed doses. mRECIST ORR was higher with increasing total perfused TAD (odds ratio per 100 Gy TAD increase was 1.22 (95% CI: 1.01-1.49; p = 0.044) for anatomic and 1.19 (95% CI: 1.04-1.37; p = 0.012) for [99mTc]TcMAA threshold segmentation. Higher total perfused TAD was associated with improved OS (hazard ratio per 100 Gy TAD increase was 0.826 (95% CI: 0.714-0.954; p = 0.009) and 0.847 (95% CI: 0.765-0.936; p = 0.001) for anatomic and [99mTc]TcMAA threshold segmentation, respectively). For pre- vs. post-treatment dosimetry comparison, the average bias for total perfused TAD was + 11.5 Gy (95% limits of agreement: -227.0 to 250.0) with a strong positive correlation (Pearson's correlation coefficient = 0.80). CONCLUSION: Real-world data support [99mTc]TcMAA imaging to estimate absorbed doses prior to treatment of HCC with glass [90Y]yttrium microspheres. Both anatomic and [99mTc]TcMAA threshold methods were suitable for treatment planning. TRIAL REGISTRATION NUMBER: NCT03295006.

Outcomes Analysis of Yttrium-90 Radioembolization for Tumors Other Than Metastatic Colorectal Cancer from the Radiation-Emitting SIR-Spheres in Nonresectable (RESiN) Registry.

PURPOSE: To characterize the response and survival outcomes of yttrium-90 (90Y) transarterial radioembolization (TARE) for unresectable, liver-dominant metastases from primary neoplasms other than colorectal carcinoma. MATERIALS AND METHODS: This study included 1,474 patients enrolled in the Radiation-Emitting Society of Interventional Radiology (SIR)-Spheres in Nonresectable Liver Tumor registry who received resin 90Y-TARE as part of their oncologic management for unresectable primary or secondary liver tumors (NCT02685631). Of these patients, 33% (481/1,474) were treated for liver metastases of noncolorectal origin (m-non-CRC) compared with 34% (497/1,474) treated for metastatic colorectal cancer (mCRC) and 34% (496/1,474) treated for hepatocellular carcinoma. Treatment response and cancer survival probabilities were computed and compared for each primary cancer type. The Kaplan-Meier method and log-rank test were used to compare survival outcomes. RESULTS: Radiological responses were observed in 12 unique cancer types, mostly heavily pretreated malignancies refractory to multiple lines of systemic therapies. The overall use of resin 90Y-TARE in m-non-CRC resulted in better treatment outcomes in terms of duration of response, progression-free survival, time to progression, and overall survival (P = .04, P = .02, P = .01, and P = .04, respectively). Analyses of cancer cell types revealed that metastatic neuroendocrine tumor, sarcoma, and ovarian, renal, prostate, and breast cancers were associated with superior treatment outcomes, whereas worse treatment outcomes were observed in metastatic lung, gastric, pancreatic, and esophageal cancers. CONCLUSIONS: Real-world data demonstrate the use of resin 90Y-TARE in m-non-CRC refractory to standard chemotherapy. For some cell types, this expanded use achieved superior treatment outcomes relative to the reference standard of mCRC, suggesting the need for inquiry into broadened indications for 90Y-TARE.

Multidisciplinary Delphi Consensus on Safety of Combining Transarterial Radioembolization with Yttrium-90 Microspheres with Systemic Anticancer Agents for the Treatment of Liver Malignancy.

PURPOSE: To provide guidance, via multidisciplinary consensus statements, on the safety interactions between systemic anticancer agents (such as radiosensitizing chemotherapy, immunotherapy, targeted therapy, and peptide receptor radionuclide therapy) and transarterial radioembolization (TARE) with yttrium-90 (90Y)-labeled microspheres in the treatment of primary and metastatic liver malignancies. MATERIALS AND METHODS: A literature search identified 59 references that informed 26 statements on the safety of 90Y TARE combined with systemic therapies. Modified Delphi method was used to develop consensus on statements through online anonymous surveys of the 12 panel members representing the fields of interventional radiology, medical oncology, surgical oncology, hepatology, and pharmacy, focusing on hepatocellular carcinoma (HCC), metastatic colorectal cancer (mCRC), neuroendocrine tumors, metastatic breast cancer, and intrahepatic cholangiocarcinoma. RESULTS: High-level evidence was limited. Level 1 data in patients with mCRC suggest that some radiosensitizing chemotherapies (eg, oxaliplatin) require temporary dose reduction when used concomitantly with 90Y TARE, and some targeted therapies (eg, vascular endothelial growth factor inhibitors and antiangiogenic tyrosine kinase inhibitors) should be avoided for at least 4 weeks before 90Y TARE. In patients with HCC, the feasibility of 90Y TARE and immunotherapy has been demonstrated with Level 4 evidence. Data are more limited for other primary and secondary liver malignancies, and consensus statements were driven by expert opinion (Level 5). CONCLUSIONS: Given the absence of evidence-based guidelines on the safety of 90Y TARE in combination with systemic anticancer therapy, these consensus statements provide expert guidance on the potential risks when considering specific combinations.

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.

The IR Trainee Workforce 10 Years after Becoming a Primary Medical Specialty.

The recognition of interventional radiology (IR) as a primary medical specialty and the subsequent development of IR residency programs initiated a new wave of development in the field. The shift from recruiting from the pool of diagnostic radiology residents to the pool of medical students offered a new opportunity to evolve the composition of the IR workforce. After a decade of specialty status, the composition of IR's workforce and pipeline shows progress in its reflection of national demographical changes. Increasing diversification of practitioners in IR is an aggressive growth strategy, which is necessary to serve a diversifying population. Increasing the diversity of the IR workforce offers the potential to promote access to and utilization of IR and improve the quality of care. Cultivating a more diverse workforce utilizes untapped potential critical to the continued growth of IR.

Effect of Previous Transarterial Chemoembolization on Survival and Toxicity after Yttrium-90 Transarterial Radioembolization of Hepatocellular Carcinoma in the Radiation-Emitting SIR-Spheres in Nonresectable Liver Tumor Registry.

PURPOSE: To determine overall survival (OS), best response, and toxicities in patients with hepatocellular carcinoma (HCC) previously treated with chemoembolization (TACE+) or yttrium-90 resin transarterial radioembolization (TARE) compared with those of TACE-naïve (T-N) participants. MATERIALS AND METHODS: In this prospective, observational study, 262 adult participants with HCC were divided into TACE+ (n = 93, 35%) or T-N (n = 169, 65%) groups, included from 36 centers in the United States. Overall survival (OS) was assessed using Kaplan-Meier analysis from the date of TARE. Best response at 6 months was evaluated using modified Response Evaluation Criteria in Solid Tumors. Six-month toxicities were reported using Common Terminology Criteria for Adverse Events, version 5. RESULTS: Median OS for patients in the TACE+ and T-N groups was 22.3 months (95% CI: 17.2 to not reachable) and 21.5 months (95% confidence interval [CI]: 14.9-29.9), respectively (P = .6). Imaging at 6 months ± 2 weeks was available in 156 of 262 (60%) participants. Partial or complete response was seen in 27 of 55 patients (49%) in the TACE+ group and 65 of 101 patients (64%) in the T-N group (P = .2). Six-month toxicities were available in 69 of 93 patients (74%) in the TACE+ group and 135 of 167 patients (81%) in the T-N group. Attributable Grade 3 or greater liver function toxicities were similar between the study groups (all P > .05). CONCLUSIONS: OS and imaging response at 6 months in the TACE+ group was similar to that in the T-N group with similar toxicities. Radioembolization is an acceptable treatment option for patients with HCC previously treated with TACE.

Survival and Toxicities after Yttrium-90 Transarterial Radioembolization of Cholangiocarcinoma in the RESiN Registry.

PURPOSE: To report outcomes in patients with intrahepatic cholangiocarcinoma treated with yttrium-90 resin microspheres (transarterial radioembolization [TARE]) from a multicenter, prospective observational registry. MATERIALS AND METHODS: Ninety-five patients (median age, 67 years [interquartile range {IQR}, 59-74]; 50 men) were treated in 27 centers between July 2015 and August 2020. Baseline demographic characteristics included imaging findings, performance status, and previous systemic or locoregional treatments. Dosimetry method was tracked. Overall survival (OS) and progression-free survival were calculated using the Kaplan-Meier method. The best imaging response was calculated using the Response Evaluation Criteria in Solid Tumors v1.1. Grade ≥3 toxicities were assessed using Common Terminology Criteria for Adverse Events v5. Cox regression analysis was performed. RESULTS: Fifty-two of 86 (60%) patients had multifocal tumors, and 24/89 (27%) had extrahepatic tumors. The median index tumor diameter was 7.0 cm (IQR, 4.9-10 cm). The activity calculation method was reported in 59/95 (62%) patients, with body surface area being the most frequently used method (45/59, 76%). Median OS for the cohort was 14 months (95% confidence interval, 12-22). OS at 3, 6, 12, and 24 months was 94%, 80%, 63%, and 34%, respectively. Median OS was longer in patients without cirrhosis (19.1 vs 12.2 months, P = .05). Cirrhosis, previous chemotherapy (OS, 19.1 vs 10.6 months for treatment-naïve; P = .07), and imaging response at 6 months (OS, 16.4 vs 9.5 months for no response; P = .06) underwent regression analysis. Imaging response predicted OS at regression (hazard ratio, 0.39; P = .008). Grade 3-4 bilirubin toxicities were noted in 5 of 72 (7%) patients. Grade 3 albumin toxicity was noted in 1 of 72 (1.4%) patients. CONCLUSIONS: Objective response at 6 months predicted longer OS after TARE for intrahepatic cholangiocarcinoma. The incidence of liver function toxicity was <10%.

Survival and Toxicities after 90Y Transarterial Radioembolization of Metastatic Colorectal Cancer in the RESIN Registry.

Background Patients with unresectable, chemorefractory hepatic metastases from colorectal cancer have considerable mortality. The role of transarterial radioembolization (TARE) with yttrium 90 (90Y) microspheres is not defined because most reports are from a single center with limited patient numbers. Purpose To report outcomes in participants with colorectal cancer metastases treated with resin 90Y microspheres from a prospective multicenter observational registry. Materials and Methods This study treated enrolled adult participants with TARE using resin microspheres for liver-dominant metastatic colorectal cancer at 42 centers, with enrollment from July 2015 through August 2020. TARE was used as the first-, second-, or third-line therapy or beyond. Overall survival (OS), progression-free survival (PFS), and toxicity outcomes were assessed by line of therapy by using Kaplan-Meier analysis for OS and PFS and Common Terminology Criteria for Adverse Events, version 5, for toxicities. Results A total of 498 participants (median age, 60 years [IQR, 52-69 years]; 298 men [60%]) were treated. TARE was used in first-line therapy in 74 of 442 participants (17%), second-line therapy in 180 participants (41%), and third-line therapy or beyond in 188 participants (43%). The median OS of the entire cohort was 15.0 months (95% CI: 13.3, 16.9). The median OS by line of therapy was 13.9 months for first-line therapy, 17.4 months for second-line therapy, and 12.5 months for third-line therapy (χ2 = 9.7; P = .002). Whole-group PFS was 7.4 months (95% CI: 6.4, 9.5). The median PFS by line of therapy was 7.9 months for first-line therapy, 10.0 months for second-line therapy, and 5.9 months for third-line therapy (χ2 = 8.3; P = .004). TARE-attributable grade 3 or 4 hepatic toxicities were 8.4% for bilirubin (29 of 347 participants) and 3.7% for albumin (13 of 347). Grade 3 and higher toxicities were greater with third-line therapy for bilirubin (P = .01) and albumin (P = .008). Conclusion Median overall survival (OS) after transarterial radioembolization (TARE) with yttrium 90 microspheres for liver-dominant metastatic colorectal cancer was 15.0 months. The longest OS was achieved when TARE was part of second-line therapy. Grade 3 or greater hepatic function toxicity rates were less than 10%. Clinical trial registration no. NCT02685631 Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Liddell in this issue.

A global evaluation of advanced dosimetry in transarterial radioembolization of hepatocellular carcinoma with Yttrium-90: the TARGET study.

PURPOSE: To investigate the relationships between tumor absorbed dose (TAD) or normal tissue absorbed dose (NTAD) and clinical outcomes in hepatocellular carcinoma (HCC) treated with yttrium-90 glass microspheres. METHODS: TARGET was a retrospective investigation in 13 centers across eight countries. Key inclusion criteria: liver-dominant HCC with or without portal vein thrombosis, < 10 tumors per lobe (at least one ≥ 3 cm), Child-Pugh stage A/B7, BCLC stages A-C, and no prior intra-arterial treatment. Multi-compartment pre-treatment dosimetry was performed retrospectively. Primary endpoint was the relationship between ≥ grade 3 hyperbilirubinemia (such that > 15% of patients experienced an event) without disease progression and NTAD. Secondary endpoints included relationships between (1) objective response (OR) and TAD, (2) overall survival (OS) and TAD, and (3) alpha fetoprotein (AFP) and TAD. RESULTS: No relationship was found between NTAD and ≥ grade 3 hyperbilirubinemia, which occurred in 4.8% of the 209 patients. The mRECIST OR rate over all lesions was 61.7%; for the target (largest) lesion, 70.8%. Responders and non-responders had geometric mean total perfused TADs of 225.5 Gy and 188.3 Gy (p = 0.048). Probability of OR was higher with increasing TAD (p = 0.044). Higher TAD was associated with longer OS (HR per 100 Gy increase = 0.83, 95% CI: 0.71-0.95; p = 0.009). Increased TAD was associated with higher probability of AFP response (p = 0.046 for baseline AFP ≥ 200 ng/mL). CONCLUSION: Real-world data confirmed a significant association between TAD and OR, TAD and OS, and TAD and AFP response. No association was found between ≥ grade 3 hyperbilirubinemia and NTAD. TRIAL REGISTRATION NUMBER: NCT03295006.

Long-term outcomes following 90Y Radioembolization of neuroendocrine liver metastases: evaluation of the radiation-emitting SIR-spheres in non-resectable liver tumor (RESiN) registry.

BACKGROUND: The goal of this study was to evaluate efficacy and safety of 90Y radioembolization for neuroendocrine liver metastases (NELM) in a multicenter registry. METHODS: One hundred-seventy patients with NELM were enrolled in the registry (NCT02685631). Prior treatments included hepatic resection (n = 23, 14%), arterial therapy (n = 62, 36%), octreotide (n = 119, 83%), cytotoxic chemotherapy (n = 58, 41%), biologic therapy (n = 49, 33%) and immunotherapy (n = 10, 6%). Seventy-seven (45%) patients had extrahepatic disease. Seventy-eight (48%), 61 (37%), and 25 (15%) patients were Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or ≥ 2. Tumor grade was known in 81 (48%) patients: 57 (70%) were well-, 12 (15%) moderate-, and 12 (15%) poorly-differentiated. Kaplan-Meier analysis and log rank tests were performed to compare overall and progression-free survival (OS/PFS) by tumor location and grade. Toxicities were reported using Common Terminology Criteria for Adverse Events v.5. Cox Proportional Hazards were calculated for pancreatic primary, performance status, extrahepatic disease at treatment, unilobar treatment, baseline ascites, and > 25% tumor burden. RESULTS: One, 2, and 3-year OS rates were 75, 62 and 46%, respectively. Median OS was 33 months [(95% CI: 25-not reached (NR)]. The longest median OS was in patients with pancreatic (42 months, 95% CI: 33-NR) and hindgut 41 months, 95% CI: 12-NR) primaries. The shortest OS was in foregut primaries (26 months; 95% CI: 23-NR; X2 = 7, p = 0.1). Median OS of well-differentiated tumors was 36 months (95% CI: 10-NR), compared to 44 (95% CI: 7-NR) and 25 (95% CI: 3-NR) months for moderate and poorly differentiated tumors. Median progression-free survival (PFS) was 25 months with 1, 2, and 3-year PFS rates of 70, 54, and 35%, respectively. Thirteen patients (7.6%) developed grade 3 hepatic toxicity, most commonly new ascites (n = 8, 5%) at a median of 5.5 months. Performance status of ≥2 (HR 2.7, p = 0.01) and baseline ascites (HR 2.8, P = 0.049) predicted shorter OS. DISCUSSION: In a population with a high incidence of extrahepatic disease, 90Y was effective and safe in treatment of NELM, with median OS of 41 months for well differentiated tumors. Grade 3 or greater hepatic toxicity was developed in 7.6% of patients. TRIAL REGISTRATION: NCT02685631 .

Overall survival and toxicity of Y90 radioembolization for hepatocellular carcinoma patients in Barcelona Clinic Liver Cancer stage C (BCLC-C).

INTRODUCTION: National Comprehensive Cancer Network HCC guidelines recommend Y90 to treat BCLC-C patients only in select cases given the development of systemic regimens. We sought to identify ideal candidates for Y90 by assessing survival and toxicities in this patient group. MATERIALS AND METHODS: The Radiation-Emitting Selective Internal radiation spheres in Non-resectable tumor registry is a prospective observational study (NCT: 02,685,631). Patients with advanced HCC were stratified into 3 groups based on tumor location, Eastern Cooperative Oncology Group (ECOG) performance status, and liver function. Group 1: liver isolated HCC, ECOG 0 and Child Pugh (CP) A (n = 12, 16%), Group 2: liver isolated HCC, ECOG ≥ 1 or CP B/C (n = 37, 49%), and Group 3: extrahepatic HCC with any ECOG or CP score (n = 26, 35%). Patients in any group could have macrovascular invasion. Overall survival (OS) and progression-free survival (PFS) with 95% confidence intervals (95% CI) were calculated. Grade 3 + toxicities were tracked using Common Terminology Criteria for Adverse Events v5. Cox proportional hazard model was performed to determine factors affecting OS. RESULTS: Seventy-five BCLC-C patients treated between 2015 and 2019 were reviewed. The groups were similar in age, sex, race, and ethnicity (all p > 0.05). Bilobar disease was least common in Group 1 (p < 0.001). Median OS of the entire cohort was 13.6 (95% CI 7.5-16.1) months. Median OS of Groups 1-3 were 21.8, 13.1 and 11.5 months respectively (p = 0.6). Median PFS for the cohort was 6.3 (4.8-14.7) months. Median PFS for group 1 was not reached. Mean PFS for Group 1 was 17.3 ± 4.8 months. Median PFS for Groups 2 and 3 was 6.8 and 5.9 months (X2 = 1.5, p = 0.5). Twenty-four Grade 3 or greater toxicities developed, most commonly hyperbilirubinemia (8/75, 11%) and thrombocytopenia (2/75, 3%). The incidence of toxicities between groups was similar (all p > 0.05). Cox Proportional Hazard analysis predicted shorter OS with CP class B/C (X2 = 6.7, p = 0.01), while macrovascular invasion (X2 = 0.5, p = 0.5) and ECOG score of ≥ 1 (X2 = 2.1, p = 0.3) was not associated with OS. CONCLUSIONS: OS of CPA patients with advanced HCC and performance status of 0 was 21.8 months following Y90. CP A cirrhosis is the best predictor of prolonged OS in advanced (BCLC-C) HCC.

High quality imaging and dosimetry for yttrium-90 (90Y) liver radioembolization using a SiPM-based PET/CT scanner.

PURPOSE: Transarterial radioembolization (TARE) with yttrium-90 (90Y) microspheres is a liver-directed treatment for primary and secondary hepatic malignancies. Personalized dosimetry aims for maximum treatment effect and reduced toxicity. We aimed to compare pre-treatment voxel-based dosimetry from 99mTc macroaggregated albumin (MAA) SPECT/CT with post-treatment 90Y PET/CT for absorbed dose values, and to evaluate image quality of 90Y SiPM-based PET/CT. METHODS: Forty-two patients (28 men, 14 women, mean age: 67 ± 11 years) with advanced hepatic malignancies were prospectively enrolled. Twenty patients were treated with glass and 22 with resin microspheres. Radiation absorbed doses from planning 99mTc-MAA SPECT/CT and post-therapy 90Y PET/CT were assessed. 90Y PET/CT images were acquired for 20 min and reconstructed to produce 5-, 10-, 15-, and 20-min datasets, then evaluated using the 5-point Likert scale. RESULTS: The mean administered activity was 3.44 ± 1.5 GBq for glass and 1.62 ± 0.7 GBq for resin microspheres. The mean tumor absorbed doses calculated from 99mTc-MAA SPECT/CT and 90Y PET/CT were 175.69 ± 113.76 Gy and 193.58 ± 111.09 Gy (P = 0.61), respectively for glass microspheres; they were 60.18 ± 42.20 Gy and 70.98 ± 49.65 Gy (P = 0.37), respectively for resin microspheres. The mean normal liver absorbed doses from 99mTc-MAA SPECT/CT and 90Y PET/CT were 32.70 ± 22.25 Gy and 30.62 ± 20.09 Gy (P = 0.77), respectively for glass microspheres; they were 18.33 ± 11.08 Gy and 24.32 ± 15.58 Gy (P = 0.17), respectively for resin microspheres. Image quality of 90Y PET/CT at 5-, 10-, 15-, and 20-min scan time showed a Likert score of 3.6 ± 0.54, 4.57 ± 0.58, 4.84 ± 0.37, and 4.9 ± 0.3, respectively. CONCLUSIONS: 99mTc-MAA SPECT/CT demonstrated great accuracy for treatment planning dosimetry. SiPM-based PET/CT scanner showed good image quality at 10-min scan time, acquired in one bed position. A PET/CT scan time of 5 min showed acceptable image quality and suffices for dosimetry and treatment verification. This allows for inclusion of 90Y PET/CT in busy routine clinical workflows. Studies with larger patient cohorts are needed to confirm these findings.

International recommendations for personalised selective internal radiation therapy of primary and metastatic liver diseases with yttrium-90 resin microspheres.

PURPOSE: A multidisciplinary expert panel convened to formulate state-of-the-art recommendations for optimisation of selective internal radiation therapy (SIRT) with yttrium-90 (90Y)-resin microspheres. METHODS: A steering committee of 23 international experts representing all participating specialties formulated recommendations for SIRT with 90Y-resin microspheres activity prescription and post-treatment dosimetry, based on literature searches and the responses to a 61-question survey that was completed by 43 leading experts (including the steering committee members). The survey was validated by the steering committee and completed anonymously. In a face-to-face meeting, the results of the survey were presented and discussed. Recommendations were derived and level of agreement defined (strong agreement ≥ 80%, moderate agreement 50%-79%, no agreement ≤ 49%). RESULTS: Forty-seven recommendations were established, including guidance such as a multidisciplinary team should define treatment strategy and therapeutic intent (strong agreement); 3D imaging with CT and an angiography with cone-beam-CT, if available, and 99mTc-MAA SPECT/CT are recommended for extrahepatic/intrahepatic deposition assessment, treatment field definition and calculation of the 90Y-resin microspheres activity needed (moderate/strong agreement). A personalised approach, using dosimetry (partition model and/or voxel-based) is recommended for activity prescription, when either whole liver or selective, non-ablative or ablative SIRT is planned (strong agreement). A mean absorbed dose to non-tumoural liver of 40 Gy or less is considered safe (strong agreement). A minimum mean target-absorbed dose to tumour of 100-120 Gy is recommended for hepatocellular carcinoma, liver metastatic colorectal cancer and cholangiocarcinoma (moderate/strong agreement). Post-SIRT imaging for treatment verification with 90Y-PET/CT is recommended (strong agreement). Post-SIRT dosimetry is also recommended (strong agreement). CONCLUSION: Practitioners are encouraged to work towards adoption of these recommendations.

Multicenter Evaluation of Survival and Toxicities of Hepatocellular Carcinoma following Radioembolization: Analysis of the RESiN Registry.

PURPOSE: To determine overall survival (OS), progression-free survival (PFS), and toxicity in patients with hepatocellular carcinoma (HCC) in a multicenter, real-world data registry using transarterial radioembolization (TARE) with resin microspheres. MATERIALS AND METHODS: A total of 448 patients with HCC were treated at 36 centers between 2015 and 2019. Treatment history, baseline laboratory and imaging, and treatment goal were assessed. OS and PFS were stratified using Barcelona Clinic Liver Cancer (BCLC) and Child-Pugh (CP) classifications. Kaplan-Meier analyses compared OS and PFS with 95% confidence intervals. Transplants were tracked. Toxicities were assessed using Common Terminology Criteria for Adverse Events v5. Cox proportional hazard of baseline demographics assessed factors affecting survival. RESULTS: Prior chemoembolization and systemic therapy were used in 107 (26%) and 68 (16%) patients, respectively. Using the BCLC staging system, 66 patients (19%) were BCLC A and 202, 51, and 26 were BCLC B, C, and D, respectively. Median OS for patients with BCLC A disease was not achieved at 30 months. Median OS for patients with BCLC B, C, and D disease were 19.5, 13.6, and 11.5 months, respectively (P = .0006). Median PFS for patients with BCLC A, B, C, and D were 19.8, 10.0, 6.3, and 5.9 months, respectively (P = .003). Twenty patients underwent transplantation, representing 14 of 43 (33%) and 6 of 28 (21%) patients who underwent bridging and downstaging therapy, respectively. Common Grade 3 toxicities were encephalopathy (11/448, 2.5%), hyperbilirubinemia (10/448, 2.2%), and ascites (9/448, 2.0%). Factors predicting longer survival included CP A (χ2 = 4.2, P = .04) and BCLC A (χ2 = 5.2, P = .02). CONCLUSIONS: In a frequently pretreated patient cohort with disease burden in 81% beyond the Milan criteria, TARE with resin microspheres provided OS comparable to other studies in this multicenter registry.

Bronchial Artery Embolization for Hemoptysis in Cystic Fibrosis Patients: A 17-Year Review.

PURPOSE: To review safety and efficacy of bronchial artery embolization (BAE) for treatment of hemoptysis in adult patients with cystic fibrosis (CF) and to report 30-day, 1-year, and 3-year outcomes. MATERIALS AND METHODS: Between January 2001 and April 2018, 242 patients with CF were evaluated for hemoptysis. Thirty-eight BAEs were performed in 28 patients with hemoptysis. Technical success was defined as freedom from repeat embolization and hemoptysis-related mortality. Clinical success was defined as freedom from repeat embolization and mortality from any cause. Technical and clinical success were examined at 30 days, 1 year, and 3 years after initial BAE. Mean patient age was 32 years, and median follow-up was 4.8 years (range, 10 mo to 16.7 y). RESULTS: Technical and clinical success rates at 30 days were 89% (25/28) and 82% (23/28), respectively. Success rates at 1 year were 86% (24/28) and 79% (22/28), respectively, and at 3 years were 82% (23/28) and 75% (21/28), respectively. The 30-day overall complication rate was 7.9% (3/38) with 2.6% (1/38) major complication rate and 5.2% (2/38) minor complication rate. Overall 3-year mortality rate was 25% (7/28). CONCLUSIONS: BAE is safe and effective in patients with CF presenting with life-threatening hemoptysis. BAE results in high rates of long-term technical and clinical success in this patient population despite progressive chronic disease. Repeat embolization is necessary only in a minority of patients.

Feasibility of Augmented Reality-Guided Transjugular Intrahepatic Portosystemic Shunt.

PURPOSE: To investigate an augmented reality (AR)-guided endovascular puncture to facilitate successful transjugular intrahepatic portosystemic shunt (TIPS). MATERIALS AND METHODS: An AR navigation system for TIPS was designed. Three-dimensional (3D) liver models including portal and hepatic vein anatomy were extracted from preoperative CT images. The 3D models, intraoperative subjects, and electromagnetic tracking information of the puncture needles were integrated through the system calibration. In the AR head-mounted display, the 3D models were overlaid on the subjects, which was a liver phantom in the first phase and live beagle dogs in the second phase. One life-size liver phantom and 9 beagle dogs were used in the experiments. Imaging after puncture was performed to validate whether the needle tip accessed the target hepatic vein successfully. RESULTS: Endovascular punctures of the portal vein of the liver phantom were repeated 30 times under the guidance of the AR system, and the puncture needle successfully accessed the target vein during each attempt. In the experiments of live canine subjects, the punctures were successful in 2 attempts in 7 beagle dogs and in 1 attempt in the remaining 2 dogs. The puncture time of needle from hepatic vein to portal vein was 5-10 s in the phantom experiments and 10-30 s in the canine experiments. CONCLUSIONS: The feasibility of AR-based navigation facilitating accurate and successful portal vein access in preclinical models of TIPS was validated.

Lower Extremity Venous Stent Placement: A Large Retrospective Single-Center Analysis.

PURPOSE: To study short-term and long-term outcomes of lower extremity venous stents placed at a single center and to characterize changes in vein diameter achieved by stent placement. MATERIALS AND METHODS: A database of all patients who received lower extremity venous stents between 1996 and 2018 revealed 1,094 stents were placed in 406 patients (172 men, 234 women; median age, 49 y) in 513 limbs, including patients with iliocaval stents (9.4% acute thrombosis, 65.3% chronic thrombosis, 25.3% nonthrombotic lesions). Primary, primary assisted, and secondary patency rates were assessed for lower extremity venous stents at 1, 3, and 5 years using Kaplan-Meier analyses and summary statistics. Subset analyses and Cox regression were performed to identify risk factors for patency loss. Vein diameters and Villalta scores before and up to 12 months after stent placement were compared. Complication and mortality rates were calculated. RESULTS: Primary, primary assisted, and secondary patency rates at 5 years were 57.3%, 77.2%, and 80.9% by Kaplan-Meier methods and 78.6%, 90.3%, and 92.8% by summary statistics. Median follow-up was 199 days (interquartile range, 35.2-712.0 d). Patency rates for the subset of patients (n = 46) with ≥ 5 years of follow-up (mean ± SD 9.1 y ± 3.4) were nearly identical to cohort patency rates at 5 years. Patients with inferior vena cava stent placement (hazard ratio 2.11, P < .0001) or acute thrombosis (hazard ratio 3.65, P < .0001) during the index procedure had significantly increased risk of losing primary patency status. Vein diameters were significantly greater after stent placement. There were no instances of stent fracture, migration, or structural deformities. In patients with chronic deep vein thrombosis, Villalta scores significantly decreased after stent placement (from 15.7 to 7.4, P < .0001). Perioperative mortality was < 1%, and major perioperative complication rate was 3.7%. CONCLUSIONS: Cavo-ilio-femoral stent placement for venous occlusive disease achieves improvement of vein disease severity scores, increase in treated vein diameters, and satisfactory long-term patency rates.

Yttrium-90 Radioembolization in Intrahepatic Cholangiocarcinoma: A Multicenter Retrospective Analysis.

PURPOSE: To report outcomes of yttrium-90 (90Y) radioembolization in patients with unresectable intrahepatic cholangiocarcinoma (ICC). MATERIALS AND METHODS: Retrospective review was performed of 115 patients at 6 tertiary care centers; 92 were treated with resin microspheres (80%), 22 were treated with glass microspheres (19%), and 1 was treated with both. Postintervention outcomes were compared between groups with χ2 tests. Survival after diagnosis and after treatment was assessed by Kaplan-Meier method. RESULTS: Grade 3 laboratory toxicity was observed in 4 patients (4%); no difference in toxicity profile between resin and glass microspheres was observed (P = .350). Clinical toxicity per Society of Interventional Radiology criteria was noted in 29 patients (25%). Partial response per Response Evaluation Criteria In Solid Tumors 1.1 was noted in 25% of patients who underwent embolization with glass microspheres and 3% of patients who were treated with resin microspheres (P = .008). Median overall survival (OS) from first diagnosis was 29 months (95% confidence interval [CI], 21-37 mo) for all patients, and 1-, 3-, and 5-year OS rates were 85%, 31%, and 8%, respectively. Median OS after treatment was 11 months (95% CI, 8-13 mo), and 1- and 3-year OS rates were 44% and 4%, respectively. These estimates were not significantly different between resin and glass microspheres (P = .730 and P = .475, respectively). Five patients were able to undergo curative-intent resection after 90Y radioembolization (4%). CONCLUSIONS: This study provides observational data of treatment outcomes after 90Y radioembolization in patients with unresectable ICC.

Toward Data-Driven Learning Healthcare Systems in Interventional Radiology: Implementation to Evaluate Venous Stent Patency.

We developed a code and data-driven system (learning healthcare system) for gleaning actionable clinical insight from interventional radiology (IR) data. To this end, we constructed a workflow for the collection, processing and analysis of electronic health record (EHR), imaging, and cancer registry data for a cohort of interventional radiology patients seen in the IR Clinic at our institution over a more than 20-year period. As part of this pipeline, we created a database in REDCap (VITAL) to store raw data, as collected by a team of clinical investigators and the Data Coordinating Center at our university. We developed a single, universal pre-processing codebank for our VITAL data in R; in addition, we also wrote widely extendable and easily modifiable analysis code in R that presents results from summary statistics, statistical tests, visualizations, Kaplan-Meier analyses, and Cox proportional hazard modeling, among other analysis techniques. We present our findings for a test case of supra versus infra-inguinal ligament stenting. The developed pre-processing and analysis pipelines were memory and speed-efficient, with both pipelines running in less than 2 min. Three different supra-inguinal ligament veins had a statistically significant improvement in vein diameters post-stenting versus pre-stenting, while no infra-inguinal ligament veins had a statistically significant improvement (due either to an insufficient sample size or a non-significant p value). However, infra-inguinal ligament stenting was not associated with worse restenosis or patency outcomes in either a univariate (summary-statistics and Kaplan-Meier based) or multivariate (Cox proportional hazard model based) analysis.