Embolization of hepatic arterial branches to simplify hepatic blood flow before yttrium 90 radioembolization: a useful technique in the presence of challenging anatomy

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.

Catheter-Directed Computed Tomography Hepatic Angiography for Yttrium-90 Selective Internal Radiotherapy of Hepatocellular Carcinoma Reduces Prophylactic Embolization of Extrahepatic Vessels

OBJECTIVES

To determine the rate of prophylactic embolization of extrahepatic vessels in patients undergoing yttrium-90 selective internal radiotherapy (⁹⁰Y SIRT) for hepatocellular carcinoma (HCC) with the use of catheter-directed computed tomography hepatic angiography (CD-CTHA).

MATERIALS AND METHODS

This retrospective study included 186 HCC patients who received ⁹⁰Y SIRT from May 2010 to June 2015 in a single institution. All procedures were performed in a hybrid angiography-CT suite equipped with digital subtraction angiography (DSA) and CD-CTHA capabilities. CD-CTHA was performed during pre-treatment hepatic angiography. ⁹⁰Y SIRT was administered approximately 2 weeks later. Selective prophylactic embolization of extrahepatic vessels was performed if extrahepatic enhancement was seen on CD-CTHA or if an extrahepatic vessel opacified on DSA/CD-CTHA despite the final microcatheter position for ⁹⁰Y microsphere delivery being beyond the origin of this vessel.

RESULTS

Thirty-five patients (18.8%) required selective embolization of extrahepatic vessels. Technical success of ⁹⁰Y SIRT was 99.5%. Two patients (1.1%) developed radiation-induced gastrointestinal ulceration, and one (0.54%) developed radiation-induced pneumonitis. Extrahepatic uptake of ⁹⁰Y microspheres was seen in the gallbladder of one patient without significant complications.

CONCLUSION

The use of CD-CTHA in ⁹⁰Y SIRT of HCC was associated with a low rate of prophylactic embolization of extrahepatic vessels while maintaining a high technical success rate of treatment and low rate of complications.

LEVEL OF EVIDENCE

Level 4, case series.

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 via variant hepatic arteries: Is there a relevant risk for non-target embolization?

BACKGROUND

The hepatic arterial anatomy is highly variable, with the two most common variants being a replaced right hepatic artery (RHA) originating from the superior mesenteric artery (SMA) and a left hepatic artery (LHA) originating from the left gastric artery (LGA). These anatomical variants could potentially increase the risk for non-target embolization during Y90-Radioembolization due to the close proximity between hepatic and enteric vessel branches.

AIM

To evaluate the safety of Yttrium-90 radioembolization (⁹⁰Y-RE) with resin microspheres in patients with a variant hepatic arterial anatomy.

METHODS

In this retrospective single-center observational study, 11 patients who underwent RE with ⁹⁰Y-resin microspheres via a LHA originating from the LGA, and 13 patients via a RHA originating from the SMA were included. Patient and treatment data were reviewed regarding clinical and imaging evidence of non-target embolization of ⁹⁰Y-resin microspheres to the GI tract. Positioning of the tip of the microcatheter in relationship to the last hepatoenteric side branch was retrospectively analyzed using angiographic images, cone-beam CT and pre-interventional CT-angiograms.

RESULTS

None of the 24 patients developed clinical symptoms indicating a potential non-target embolization to the GI tract within the first month after ⁹⁰Y-RE. On the postinterventional ⁹⁰Y-bremsstrahlung images and/or ⁹⁰Y-positron emission tomographies, no evidence of extrahepatic ⁹⁰Y-activity in the GI tract was noted in any of the patients. The mean distance between the tip of the microcatheter and the last enteric side branch during delivery of the ⁹⁰Y microspheres was 3.2 cm (range: 1.9-5 cm) in patients with an aberrant LHA originating from a LGA. This was substantially shorter than the mean distance of 5.2 cm (range: 2.9-7.7 cm) in patients with an aberrant right hepatic originating from the SMA.

CONCLUSION

⁹⁰Y-RE via aberrant hepatic arteries appears to be safe; at least with positioning of the microcatheter tip no less than 1.9 cm distal to the last hepatoenteric side branch vessel.

Pictorial essay: imaging findings following Y90 radiation segmentectomy for hepatocellular carcinoma

Transarterial radioembolization is a novel therapy that has gained rapid clinical acceptance for the treatment of hepatocellular carcinoma (HCC). Segmental radioembolization [also termed radiation segmentectomy (RS)] is a technique that can deliver high doses (> 190 Gy) of radiation selectively to the hepatic segment(s) containing the tumor. The aim of this comprehensive review is to provide an illustrative summary of the most relevant imaging findings encountered after radiation segmentectomy. A 62-patient cohort of Child-Pugh A patients with solitary HCC < 5 cm in size was identified. A comprehensive retrospective imaging review was done by interventional radiology staff at our institution. Important imaging findings were reported and illustrated in a descriptive account. For the purposes of completeness, specific patients outside our initial cohort with unique educational imaging features that also underwent segmentectomy were included in this pictorial essay. This review shows that response assessment after RS requires a learning curve with common drawbacks that can lead to false-positive interpretations and secondary unnecessary treatments. It is important to recognize that treatment responses and pathological changes both are time dependent. Findings such as benign geographical enhancement and initial benign pathological enhancement can easily be misinterpreted. Capsular retraction and segmental atrophy are some other examples of unique post-RS response that are not seen in any other treatment.

Yttrium-90 hepatic radioembolization: clinical review and current techniques in interventional radiology and personalized dosimetry

In recent years, yttrium-90 ((90)Y) microsphere radioembolization has been establishing itself as a safe and efficacious treatment for both primary and metastatic liver cancers. This extends to both first-line therapies as well as in the salvage setting. In addition, radioembolization appears efficacious for patients with portal vein thrombosis, which is currently a contraindication for surgery, transplantation and transarterial chemoembolization. This article reviews the efficacy and expanding use of (90)Y microsphere radioembolization with an added emphasis on recent advances in personalized dosimetry and interventional radiology techniques. Directions for future research into combination therapies with radioembolization and expansion into sites other than the liver are also explored.

Radioembolization with yttrium-90 microspheres work up: Practical approach and literature review

Radioembolization (RE) is a selective internal radiotherapy technique in which yttrium-90 blended microspheres are infused through the hepatic arteries. It is based on the fact that primary and secondary hepatic tumors are vascularized mostly by arterial blood flow whereas healthy hepatocytes obtain their blood supply mostly from the portal network. This enables high radiation doses to be delivered, sparing the surrounding non-malignant liver parenchyma. Most of the complications are caused by unexpected particles passing into the gastrointestinal tract through branches originating from the main hepatic arterial supply. Knowledge of this hepatic arterial network and of its variations and the technical considerations this raises are required in preparation for treatment. This work describes the specific anatomical features and techniques for this anatomy through recent literature illustrated by cases from our own experience.

The role of 18F-FDG-PET and PET/CT in patients with colorectal liver metastases undergoing selective internal radiation therapy with yttrium-90: a first evidence-based review

PURPOSE

To provide a first evidence-based review of the literature on the role of fluorine-18-fluorodeoxyglucose positron emission tomography and positron emission tomography/computed tomography (FDG-PET and PET/CT) in patients with colorectal liver metastases (CRLM) undergoing selective internal radiation therapy (SIRT) with yttrium-90 ((90)Y) microspheres.

METHODS

A comprehensive computer literature search was conducted to find relevant published articles on whole-body FDG-PET or PET/CT in patients with CRLM undergoing SIRT.

RESULTS

We identified 19 studies including 833 patients with CRLM undergoing SIRT. The role of FDG-PET or PET/CT was analysed in treatment planning, treatment response evaluation, and as prognostic tool.

CONCLUSION

FDG-PET and PET/CT provide additional information in treatment evaluation of CRLM patients treated with SIRT and may have a role in treatment planning and patient selection. FDG-PET/CT is emerging as good prognostic tool in these patients.

Celiac Artery Stenting to Facilitate Hepatic Yttrium-90 Radioembolization Therapy

Radioembolization offers a novel way to treat the nonresectable, liver predominant hepatic malignancies with better tumor response and overall progression-free survival rates. Transarterial catheter-based radioembolization procedure involves the hepatic arterial administration of glass- or resin-based beta emitting Yttirum-90 microspheres. Safe delivery of the tumoricidal radiation dose requires careful angiogram planning and coil embolization to quantify lung shunting and prevent systemic toxicity, respectively. Diagnostic pretreatment angiogram also serves to identify the hepatic arterial variant anatomy and other coexisting pathologies that might require a different or alternative approach. We describe a complex case of celiac artery stenosis with tortuous pancreaticoduodenal arterial arcade precluding access to the right hepatic artery for performing radioembolization. Celiac artery stenting of the stenosis was performed to facilitate subsequent safe and successful Yttrium-90 microsphere radioembolization.

Radioembolization of symptomatic, unresectable neuroendocrine hepatic metastases using yttrium-90 microspheres

PURPOSE

To evaluate safety, efficacy, and symptom-control of radioembolization in patients with unresectable liver metastases from neuroendocrine tumors (NETLMs).

MATERIALS AND METHODS

Forty-two patients (mean age of 62 years) with treatment-refractory NETLMs underwent radioembolization using yttrium-90 ((90)Y) resin microspheres. Posttreatment tumor response was assessed by cross-sectional imaging using the Response Evaluation Criteria in Solid Tumors (RECIST) and tumor-marker levels. Laboratory and clinical toxicities and clinical symptoms were monitored.

RESULTS

The median activity delivered was 1.63 GBq (range 0.63-2.36). Imaging follow-up using RECIST at 3-month follow-up demonstrated partial response, stable disease, and progressive disease in 22.5, 75.0, and 2.5% of patients, respectively. In 97.5% of patients, the liver lesions appeared hypovascular or partially necrotic. The mean follow-up was 16.2 months with 40 patients (95.2%) remaining alive. The median decrease in tumor-marker levels at 3 months was 54.8% (chromogranin A) and 37.3% (serotonin), respectively. There were no acute or delayed toxicities greater than grade 2 according to Common Terminology Criteria for Adverse Events [CTCAE (v3.0)]. No radiation-induced liver disease was noted. Improvement of clinical symptoms 3 months after treatment was observed in 36 of 38 symptomatic patients.

CONCLUSION

Radioembolization with (90)Y-microspheres is a safe and effective treatment option in patients with otherwise treatment-refractory NETLMs. Antitumoral effect is supported by good local tumor control, decreased tumor-marker levels, and improved clinical symptoms. Further investigation is warranted to define the role of radioembolization in the treatment paradigm for NETLMs.