Intrahepatic Flow Redistribution in Patients Treated with Radioembolization

The double-balloon technique: a safe and effective adjunctive technique in patients undergoing arterial therapy for hepatic malignancies with vascular supply not amenable to selective administration

PURPOSE

During catheter directed intraarterial therapy for liver lesions, challenging hepatic vascular anatomy can sometimes prevent selective administration of treatment delivery to liver tumors leading to increased toxicity to normal liver parenchyma. The objective of this study is to describe a variation of the double balloon technique that isolates the feeding artery to liver tumors proximally and distally to provide treatment delivery in lesions that cannot be otherwise selected.

MATERIALS AND METHODS

An IRB-approved retrospective review of 7 patients who had undergone either radioembolization, chemoembolization, or bland embolization and the double balloon technique was employed. The devices used for flow augmentation were two 2.1 French balloon microcatheters (Sniper™, Embolx). One balloon was inflated distal to target vessel and the second was inflated proximal to protect from reflux.

RESULTS

DEB-TACE was performed in 3 cases, ⁹⁰Y was performed in 4, and bland embolization was performed in the last patient. There were no adverse effects from the procedure or clinically evident effects from non-target embolization. Mean follow up time was 286.4 +/- 200.1 days. Six of the 7 patients are alive. One patient passed away on post-procedure day 121 from septic shock unrelated to the procedure. One patient was bridged to transplant with an additional TACE of a separate lesion.

CONCLUSION

Double-balloon technique for patients undergoing ⁹⁰Y or chemoembolization is a safe adjunctive technique for super selective treatment of hepatic lesions where direct selection via catheter is not feasible. This may increase the range of lesions that can be both safely and effectively treated by catheter directed therapies.

Coil Embolization of Variant Hepatic Arteries During Percutaneous Arterial Port Catheter Placement for Intraarterial Chemotherapy: Analysis of Intrahepatic Perfusion Redistribution and Treatment Efficacy

PURPOSE

The purpose of this study was to analyze the intrahepatic perfusion redistribution after embolization of hepatic arterial variants during percutaneous arterial port catheter placement as well as to investigate the treatment efficacy of intraarterial chemotherapy in perfusion redistribution-dependent compared to redistribution-independent liver areas.

MATERIALS AND METHODS

This retrospective study included 62 patients (67.7% males, mean age of 56 ± 12 years). A replaced left hepatic artery was encountered in 36/62 (58.1%), a replaced right hepatic artery in 19/62 (30.6%) and a replaced left and right hepatic artery in 7/62 of patients (11.3%), respectively. Subjective perfusion analysis was performed on digital subtracted angiography and computed tomography (CT)/cone-beam computed tomography (CBCT) images evaluating the visibility of the main, segmental and subsegmental branches of the embolized variant hepatic artery, re-perfused from intrahepatic arterial anastomoses. For objective perfusion analysis ROI measurements on CT/CBCT images were taken in the redistribution-dependent and redistribution-independent liver lobe. Response analysis according to RECIST 1.1 was separately calculated for the redistribution-dependent and redistribution-independent liver lobe.

RESULTS

Intrahepatic reperfusion of the embolized variant hepatic artery was observed immediately after embolization with visualization of the subsegmental branches in 95.2% of patients. ROI measurements on CT/CBCT images (right lobe mean 76 ± 30.2 HU, left lobe mean 74.4 ± 30.5, p-value 0.88) did not show any differences. Treatment response after intraarterial chemotherapy did not differ between the redistribution-dependent and redistribution-independent liver lobes.

CONCLUSION

Embolization of hepatic arterial variants during percutaneous arterial port catheter placement results in effective intrahepatic perfusion redistribution and does not compromise treatment efficacy of intraarterial chemotherapy in the redistribution-dependent liver lobe.

Balloon-assisted radioembolization via the proper hepatic artery to treat a left liver hepatocellular carcinoma and portal vein tumor thrombus with an inaccessible left hepatic artery: A case report

Although yttrium-90 (⁹⁰Y) transarterial radioembolization (TARE) is an effective treatment for hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT), inability to cannulate tumor-feeding vessels can preclude its use. In this case we demonstrate the feasibility of employing balloon occlusion within the proper hepatic artery to treat a left lobar HCC and PVTT with an inaccessible left hepatic artery. Vessel angulation prevented subselection of the left hepatic artery, and subsequent mapping studies indicated significant non-target radiotracer activity. Through occlusion of the proper hepatic artery by a balloon microcatheter, flow alterations were created that led to uptake of the ⁹⁰Y microspheres by the tumor while sparing the non-diseased liver parenchyma. Thus, this innovative approach may permit the use of TARE in patients when proximal tumor vessels are inaccessible.

Radioembolization for the Treatment of Hepatocellular Carcinoma: The Road to Personalized Dosimetry and Ablative Practice

Radioembolization dosimetry for the treatment of hepatocellular carcinoma has evolved alongside our understanding of best practice for this therapy. At the core of advances in dosimetry are personalized and ablative applications of radioembolization, which have generated paradigm shifts in both safety and efficacy. This review provides a summary of fundamental radioembolization dosimetry concepts and narrates how our approach to treating patients has shifted from conventional to tailored and definitive therapy.

Embolization of variant hepatic arteries in patients undergoing percutaneous hepatic perfusion for unresectable liver metastases from ocular melanoma

PURPOSE

In patients undergoing percutaneous liver perfusion with melphalan (M-PHP), the presence of variant hepatic arteries (HAs) may require catheter repositioning and thus prolong procedure time. Coil-embolization of variant HAs may enable M-PHP with a single catheter position as occlusion of variant HAs results in redistribution of flow through preexisting intrahepatic arterial collaterals. We aimed to evaluate whether redistribution of flow has any negative effect on therapeutic response in ocular melanoma patients undergoing M-PHP.

METHODS

We retrospectively analyzed pretreatment angiograms in all 32 patients that underwent M-PHP between January 2014 and March 2017 for unresectable liver metastases from ocular melanoma. Patients that underwent embolization of a variant left HA (LHA) or middle HA (MHA) during pretreatment angiography followed by at least one technically successful M-PHP were included for further analysis. Redistribution of arterial flow was evaluated on angiography and cone-beam computed tomography (CBCT) images. In each patient, tumor response in liver segments with redistributed blood flow was evaluated using RECIST 1.1 and mRECIST, and then compared with tumor response in segments without flow redistribution. Follow-up scans were reviewed to evaluate progression of liver metastases.

RESULTS

A total of 12 patients were included. Replaced LHA embolization resulted in redistribution of flow to segment(s) 2 (n=3), 2 and 3 (n=5), and 2, 3 and 4 (n=2). MHA embolization resulted in redistribution of flow to segment 4 (n=2). Successful redistribution was confirmed by angiography and/or CBCT in all patients. Tumor response was similar for redistributed and non-redistributed liver segments in 8 out of 9 patients (89%) according to RECIST 1.1, and in 7 out of 8 patients (88%) according to mRECIST. In three patients, tumor response was not evaluable according to RECIST 1.1 or mRECIST as metastases were too small to be categorized as target lesions (n=1), or target lesions were confined to non-redistributed segments (n=2). In one patient, tumor response was not evaluable according to mRECIST as target lesions in the redistributed segments were hypovascular. After a median follow-up time of 17.1 months (range, 9.1-38.5 months), hepatic progression was seen in 9 out of 12 patients with a median time to progression of 9.9 months (range, 2.5-17.7 months). Progression of liver metastases was never seen only in the redistributed liver segments.

CONCLUSION

Flow redistribution in liver segments by coil-embolization of variant HAs is a feasible technique that does not seem to compromise tumor response in patients undergoing M-PHP.

Hepatic Flow Redistribution is Feasible in Patients with Hepatic Malignancies Undergoing Same-Day Work-Up Angiography and Yttrium-90 Microsphere Radioembolization

PURPOSE

To assess the feasibility of performing same-day vascular flow redistribution and Yttrium-90 radioembolization (90Y-RE) for hepatic malignancies.

MATERIALS AND METHODS

From November 2015 to February 2019, patients undergoing same-day hepatic flow redistribution during work-up angiography, ^99mTechnetium-labeled macroaggregated albumin (^99mTc-MAA) SPECT/CT and 90Y microsphere-RE, were recruited. Within 18 h following the delivery of 90Y resin microspheres, an 90Y-PET/CT study was performed. According to patients' vascular anatomy, flow redistribution was performed by microcoil embolization of extrahepatic branches (group A), intrahepatic non-tumoral vessels (group B) and intrahepatic tumoral arteries (group C). The accumulation of ^99mTc-MAA particles and microspheres in the redistributed areas was qualitatively evaluated using a 5-point visual scale (grade 1 = < 25% accumulation; grade 5 = 100% accumulation). Differences in the distribution of microspheres among groups were assessed with Mann-Whitney U test.

RESULTS

Twenty-two patients were treated for primary (n = 17) and secondary (n = 5) hepatic malignancies. The MAA-SPECT/CT showed uptake in all the redistributed areas. Regarding the accumulation of microspheres within the redistributed segments in all the groups, perfusion patterns were classified as 2 in 1 case, 4 in 6 cases and 5 in 15 cases. No statistically significant differences were observed between groups A and B-C (U value = 34, p = 0.32) and between groups B and C (U value = 26, p = 0.7). Mean predicted absorbed doses by the tumoral and normal hepatic tissues were 163.5 ± 131.2 Gy and 60.4 ± 69.3 Gy, respectively. Mean total procedure time (from work-up angiography to 90Y delivery) was 401 ± 0.055 min.

CONCLUSION

Performing same-day redistribution of the arterial hepatic flow to the target and 90Y-microsphere delivery is feasible in the treatment of liver tumors. Clinical Trials Registry NCT03380130.

The Efficacy of Coil Embolization to Obtain Intrahepatic Redistribution in Radioembolization: Qualitative and Quantitative Analyses

Purpose

To evaluate the efficacy of coil embolization to obtain intrahepatic redistribution in patients undergoing radioembolization.

Materials and Method

All patients treated with radioembolization at our institute were retrospectively analyzed, and all cases in which a tumor-feeding vessel was coil-embolized were selected. Two nuclear medicine physicians visually assessed the effect of redistribution. Furthermore, the redistribution of microspheres was measured by quantifying the activity distributed to the coil-embolized (dependent) segment relative to the other (non-dependent) segments and to the tumor(s) in that segment. Quantitative analysis was performed on post-treatment ⁹⁰Y-PET and ¹⁶⁶Ho-SPECT using Simplicit⁹⁰Y software. Lesion response was measured according to RECIST 1.1 criteria at 3 months post-treatment.

Results

Out of 37 cases, 32 were suitable for quantitative analysis and 37 for qualitative analysis. In the qualitative analysis, redistribution was deemed successful in 69% of cases. The quantitative analysis showed that the median ratio of the activity to the dependent embolized segments and the non-dependent segments was 0.88 (range 0.26–2.05) and 0.80 (range 0.19–1.62) for tumors in dependent segments compared with tumors in non-dependent segments. Using a cutoff ratio of 0.7 (30% lower activity concentration in comparison with the rest of the liver), 57% of cases were successful. At 3 months post-treatment, 6% of dependent tumors had partial response, 20% progressive disease, and 74% stable disease. In non-dependent tumors, this was, respectively, 16%, 20%, and 64%.

Conclusion

Coil embolization of hepatic arteries to induce redistribution of microspheres has a limited success rate. Qualitative assessment tends to overrate redistribution.

Y90 Radioembolization Dosimetry: Concepts for the Interventional Radiologist

Transarterial radioembolization (TARE) with beta particle emitting microspheres via Yttrium-90 decay has become a fundamental component of the contemporary Interventional Oncology practice. TARE continues to advance as a result of increased utilization, clinical study, technological improvements, and evolving applications. To maximize TARE safety and efficacy, a core understanding of dosimetry is essential. The intent of this overview is to provide the reader with a general survey of radiation physics and biology, device differentiation, patient selection, anatomic assessment, activity administration models, and procedural techniques involved with TARE dosimetry.

Autoradiography and biopsy measurements of a resected hepatocellular carcinoma treated with 90 yttrium radioembolization demonstrate large absorbed dose heterogeneities

Purpose

Radioembolization is an alternative palliative treatment for hepatocellular carcinoma. Here, we examine the uptake differences between tumor tissue phenotypes and present a cross-section of the absorbed dose throughout a liver tissue specimen.

Methods and materials

A patient with hepatocellular carcinoma was treated with ⁹⁰Y radioembolization followed by liver tissue resection. Gamma camera images and autoradiographs were collected and biopsy tissue samples were analyzed using a gamma well counter and light microscopy.

Results

An analysis of 25 punched biopsy tissue samples identified 4 tissue regions: Normal tissue, viable tumor tissue with and without infarcted areas, and tumor areas with postnecrotic scar tissue. Autoradiography and biopsy tissue sample measurements showed large dose differences between viable and postnecrotic tumor tissue (159 Gy vs 23 Gy).

Conclusions

Radioembolization of 90 yttrium with resin microspheres produces heterogeneous-absorbed dose distributions in the treatment of unifocal hepatic malignancies that could not be accurately determined with current gamma camera imaging techniques.

Radioembolisation of hepatocellular carcinoma: a primer

Transarterial radioembolisation (TARE) has gained increasing acceptance as an additional/alternative locoregional treatment option for hepatocellular carcinoma, and colorectal hepatic metastases that present beyond potentially curative options. This is a catheter-based transarterial selective internal brachytherapy that involves injection of radioactive microspheres (usually Y-90) that are delivered selectively to the liver tumours. Owing to the combined radioactive and microembolic effect, the findings at follow-up imaging are significantly different from that seen with other transarterial treatment options. Considering increasing confidence among clinicians, refinement in techniques and increasing number of ongoing trials, TARE is expected to gain further acceptance and become an important tool in the armamentarium for the treatment of liver malignancies. So it is imperative that all radiologists involved in the management of liver malignancies are well versed with TARE to facilitate appropriate discussion at multidisciplinary meetings to direct further management. In this article, we provide a comprehensive review on various aspects of radioembolisation with Y-90 for hepatocellular carcinoma including the patient selection, treatment planning, radiation dosimetry and treatment, side effects, follow-up imaging and future direction.

Radioembolization with 90Y glass microspheres for the treatment of unresectable metastatic liver disease from chemotherapy-refractory gastrointestinal cancers: final report of a prospective pilot study

BACKGROUND

This prospective pilot single-institution study was undertaken to document the feasibility, safety, and efficacy of radioembolization of liver-dominant metastatic gastrointestinal cancer using ⁹⁰Y glass microspheres.

METHODS

Between June 2010 and October 2013, 42 adult patients (26 men, 16 women; median age 60 years) with metastatic chemotherapy-refractory unresectable colorectal (n=21), neuroendocrine (n=11), intrahepatic bile duct (n=7), pancreas (n=2), and esophageal (n=1) carcinomas underwent 60 lobar or segmental administrations of ⁹⁰Y glass microspheres. Data regarding clinical and laboratory adverse events (AE) were collected prospectively for up to 5.5 years after radioembolization. Radiographic responses were evaluated using Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1. Time to maximum response, response duration, progression-free survival (PFS) (hepatic and extrahepatic), and overall survival (OS) were measured.

RESULTS

Median target dose and activity were 109.4 Gy and 2.6 GBq per treatment session, respectively. Majority of clinical AE were grade 1 or 2 in severity. Patients with colorectal cancer had hepatic objective response rate (ORR) of 25% and a hepatic disease control rate (DCR) of 80%. Median PFS and OS were 1.0 and 4.4 months, respectively. Patients with neuroendocrine tumors (NET) had hepatic ORR and DCR of 73% and 100%, respectively. Median PFS was 8.9 months for this cohort. DCR and median PFS and OS for patients with cholangiocarcinoma were 86%, 1.1 months, and 6.7 months, respectively.

CONCLUSIONS

⁹⁰Y glass microspheres device has a favorable safety profile, and achieved prolonged disease control of hepatic tumor burden in a subset of patients, including all patients enrolled in the neuroendocrine cohort.

Percutaneous Isolated Hepatic Perfusion for the Treatment of Unresectable Liver Malignancies

Liver malignancies are a major burden of disease worldwide. The long-term prognosis for patients with unresectable tumors remains poor, despite advances in systemic chemotherapy, targeted agents, and minimally invasive therapies such as ablation, chemoembolization, and radioembolization. Thus, the demand for new and better treatments for malignant liver tumors remains high. Surgical isolated hepatic perfusion (IHP) has been shown to be effective in patients with various hepatic malignancies, but is complex, associated with high complication rates and not repeatable. Percutaneous isolated liver perfusion (PHP) is a novel minimally invasive, repeatable, and safer alternative to IHP. PHP is rapidly gaining interest and the number of procedures performed in Europe now exceeds 200. This review discusses the indications, technique and patient management of PHP and provides an overview of the available data.