Practical vascular anatomy in the preparation of radioembolization

Synchronous Treatment of Breast Cancer Hepatic Metastases by Transarterial Radioembolization and Radiofrequency Thermoablation: A Case Report

ABSTRACT

In a 51-year-old woman affected by breast cancer, hepatic recurrence of disease was managed by concurrent 90Y-labeled glass microsphere embolization (transarterial radioembolization) and radiofrequency thermoablation. Intention-to-treat target, candidate to radioembolization, was in the IV hepatic segment; another lesion, managed with radiofrequency thermoablation, was in the VI-VII hepatic segment. Concomitant correction of a duodenocephalopancreatic shunting was performed as well. Thermoablation did not interfere with distribution of 99mTc-macroaggregated albumin and 90Y-labeled microspheres to the target and healthy liver. At our knowledge, this is the first report that combines 2 locoregional procedures in different hepatic segments on the same day.

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.

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.

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.

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 Y-90 Glass Microspheres: Do We Really Need SPECT-CT to Identify Extrahepatic Shunts?

Purpose

Selective Internal Radiation Therapy (SIRT) with ⁹⁰yttrium (Y-90) is an increasingly used therapeutic option for unresectable liver malignancies. Nontarget embolization of extrahepatic tissue secondary to vascular shunting can lead to SIRT associated complications. Our aim was to assess whether extrahepatic shunts can reliably be diagnosed based on hepatic digital subtraction angiography (DSA) or whether subsequent SPECT/CT data can provide additional information.

Materials and Methods

825 patients with hepatocellular carcinoma (n = 636), hepatic metastases (n = 158) or cholangiocellular carcinoma (n = 31) were retrospectively analyzed. During hepatic DSA 128 arteries causing shunt flow to gastrointestinal tissue were coilembolized (right gastric artery n = 63, gastroduodenal artery n = 29; branches to duodenum / pancreas n = 36). Technectium-99m-labeled human serum albumin (HSA) was injected in all 825 patients. SPECT/CT data was used to identify additional or remaining shunts to extrahepatic tissue.

Results

An unexpected uptake of HSA in extrahepatic tissue was found by SPECT/CT in 54/825 (6.5%) patients (located in stomach n = 13, duodenum n = 26, distal bowel segments n = 12, kidney n = 1, diaphragm n = 2). These patients underwent repeated DSA and newly identified shunt vessels were coilembolized in 22/54 patients, while in 12/54 patients a more distal catheter position for repeat injection of HSA was chosen. In 20/54 patients the repeated SPECT/CT data still revealed an extrahepatic HSA uptake. These patients did not receive SIRT.

Conclusion

Most extrahepatic shunts can be identified on DSA prior to Y-90 therapy. However, SPECT-CT data helps to identify additional shunts that were initially not seen on DSA.

Safety of Radioembolization with (90)Yttrium Resin Microspheres Depending on Coiling or No-Coiling of Aberrant/High-Risk Vessels

PURPOSE

To evaluate the safety of radioembolization (RE) with (90)Yttrium ((90)Y) resin microspheres depending on coiling or no-coiling of aberrant/high-risk vessels.

MATERIALS AND METHODS

Early and late toxicity after 566 RE procedures were analyzed retrospectively in accordance with the National Cancer Institute's Common Terminology Criteria for Adverse Events (CTCAE v3.0). For optimal safety, aberrant vessels were either coil embolized (n = 240/566, coiling group) or a more peripheral position of the catheter tip was chosen to treat right or left liver lobes (n = 326/566, no-coiling group).

RESULTS

Clinically relevant late toxicities (≥ Grade 3) were observed in 1% of our overall cohort. The no-coiling group had significantly less "any" (P = 0.0001) or "clinically relevant" (P = 0.0003) early toxicity. There was no significant difference (P > 0.05) in delayed toxicity in the coiling versus the no-coiling group. No RE-induced liver disease was noted after all 566 procedures.

CONCLUSION

RE with (90)Y resin microspheres is a safe and effective treatment option. Performing RE without coil embolization of aberrant vessels prior to treatment could be an alternative for experienced centers.

Anatomic variants of arteries often coil-occluded prior to hepatic radioembolization

BACKGROUND

Prior to radioembolization (RE) treatment of malignant liver lesions, many interventionalists occlude the right gastric artery (RGA), the cystic artery (CA), and the gastroduodenal artery (GDA) to prevent radioactive microspheres from entering non-target vessels.

PURPOSE

To systematically analyze anatomic variants of arteries that are important to know for the interventional radiologist performing RE of the liver.

MATERIAL AND METHODS

The computed tomography (CT) angiographies and conventional angiographies of 166 patients evaluated for RE were retrospectively analyzed for the presence of anatomic variants of the RGA, GDA, and CA.

RESULTS

The RGA was found to arise from the left hepatic artery in 42% of cases, from the proper hepatic artery in 40%, from the GDA in 10%, from the right hepatic artery in 4%, and from the common hepatic artery in 3% of cases. The GDA originated in the common hepatic artery in 97% of cases, in the left hepatic artery in 2%, and in the celiac trunk in 1% of cases. The CA arose from the right hepatic artery in 96% of cases and from the GDA in 2% of cases; in 2% of our study population, the gallbladder was supplied by small branches from the liver parenchyma.

CONCLUSION

Variant anatomy of the RGA is common, while it is quite rare for the GDA and CA. Knowledge of the variations of liver supplying arteries helps the interventionalist to embolize necessary vessels prior to RE.

Selective internal radiation therapy of hepatic tumors: procedural implications of a patent hepatic falciform artery

Selective internal radiation therapy (SIRT) using 90-yttrium is a local therapy for unresectable liver malignancies. Non-targeted 90-yttrium diversion via a patent hepatic falciform artery (HFA) is seen as risk for periprocedural complications. Therefore, this study aimed to evaluate the impact of a patent HFA on SIRT. 606 patients with SIRT between 2006 and 2012 were evaluated retrospectively. SIRT preparation was performed by digital subtraction angiography including ^99mTc-HSAM administration and subsequent SPECT/CT. Patients with an angiographically patent HFA were analyzed for procedural consequences and complications. 19 of 606 patients (3%) with an angiographically patent HFA were identified. Only 11 of these 19 patients received 90-yttrium in the hepatic vessel bed containing the HFA. Initial coil embolization of the HFA succeeded only in three of 11 patients. Out of the eight remaining patients four had no abdominal wall ^99mTc-HSAM accumulation. The other four patients presented with an abdominal wall ^99mTc-HSAM accumulation, for those a reattempt of HFA embolization was performed or ice packs were administered on the abdominal wall during SIRT. In summary, all patients tolerated SIRT well. A patent HFA should not be considered a SIRT contraindication. In patients with abdominal wall ^99mTc-HSAM accumulation HFA embolization or ice pack administration seems to prevent complications.

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.

Selective internal radiation therapy of hepatic tumours: is coiling of the gastroduodenal artery always beneficial?

AIM

To assess the effect of gastroduodenal artery (GDA) occlusion prior to selective internal radiation therapy (SIRT) with regards to arterial hepato-intestinal collateralization (HIC).

MATERIALS AND METHODS

Six hundred and six patients were scheduled for SIRT between 2006 and 2012 at University Hospital Essen, Germany. Digital subtraction angiography (DSA) followed by administration of 99m-technetium labelled human serum albumin microspheres ((99m)Tc-HSAM) and single-photon emission computed tomography combined with computed tomography (SPECT/CT) was initially performed. Depending on vascular anatomy and hepatic tumour load, GDA coil embolization was considered. In subsequent (99m)Tc-HSAM rescans or therapeutic DSA, HIC and its consequences for SIRT were analysed.

RESULTS

The GDA was occluded in 86 of 606 patients (14%). Twenty-two of these 86 patients did not undergo SIRT due to the patients' clinical status or SIRT contraindications. In 28 of the remaining 64 patients, newly apparent or reopened HIC were seen either at the site of the proximal GDA (n = 21) or in the periphery of the hepatic arteries (n = 7). In 25 of these 28 patients, the HIC could be occluded or the catheter position could be changed achieving a safe (90)Y application. However, due to the newly visible HIC in three of 28 patients, SIRT was regarded as unsafe and was abandoned.

CONCLUSION

Coil embolization of the GDA may induce arterial hepato-intestinal collaterals. Although most of these collaterals do not impede (90)Y administration, SIRT may become unfeasible in specific occasions. Hence, segmental or lobar SIRT instead of a whole-liver approach with coiling of the GDA is recommended.

Towards new response criteria in neuroendocrine tumors: which changes in MRI parameters are associated with longer progression-free survival after radioembolization of liver metastases?

PURPOSE

To evaluate the association of therapy-related changes in imaging parameters with progression-free survival (PFS) of patients with unresectable liver metastases from neuroendocrine tumors (NETLMs).

MATERIALS AND METHODS

Forty-five radioembolized patients (median age: 62 years; range: 43-75) received a pre- and 3 months posttherapeutic magnetic resonance imaging (MRI) examination. The latter were evaluated for tumor size, arterial enhancement, and necrosis pattern. Influences of therapy-related changes on PFS were analyzed. Statistical analysis included Student's t-test, Wilcoxon test, Cox regression analysis, and Kaplan-Meier curves.

RESULTS

The median percentage decrease in sum of diameters was 9.7% (range: 43.9% decrease to 15.4% increase). Twenty-one patients (47%) showed increased necrosis. Three parameters were associated with significantly longer PFS: a decrease of diameter (hazard ratio [HR]: 0.206; 95% confidence interval [CI]: 0.058-0.725; P = 0.0139), a decrease in tumor arterial enhancement (HR: 0.143; 95% CI: 0.029-0.696; P = 0.0160), and an increase in necrosis after 3 months (HR: 0.321; 95% CI: 0.104-0.990; P = 0.0480). Multivariate analysis revealed that changes in diameter and arterial enhancement have complementary information and are associated independently with long PFS.

CONCLUSION

A decrease both in sum of diameters and arterial enhancement of metastases, as well as an increase in necrosis, are associated with significantly longer PFS after radioembolization.

The origin of the cystic artery supplying hepatocellular carcinoma on digital subtraction angiography in 311 patients

PURPOSE

This study was designed to investigate the prevalence and patterns of origin of the cystic artery using selective angiography images obtained during chemoembolization.

METHODS

Between March 2007 and January 2012, 326 patients with hepatocellular carcinoma supplied by the cystic artery were treated by chemoembolization through the cystic artery. Fifteen patients were excluded due to the difficulty in determining the origin of their cystic arteries. Thus, a total of 311 patients were included in this study. Digital subtraction angiography images were reviewed retrospectively by consensus.

RESULTS

A total of 112 (36 %) patients had a total of 121 variant hepatic arteries. Double cystic arteries were present in 46 (14.8 %) patients, and total 357 cystic arteries were observed. The origin sites of the cystic artery were the following: the right hepatic artery (n = 248), the anterior sectional artery (n = 44), the segment IV artery (n = 21), the posterior sectional artery (n = 10), the left hepatic artery (n = 8), the proper hepatic artery (n = 8), the gastroduodenal artery (n = 4), and others (n = 14). In total, 103 (33 %) patients had at least one cystic artery arising from arteries other than the right hepatic artery. In patients with right hepatic artery variations, the cystic artery more frequently originated from arteries other than the right hepatic artery (p = 0.003).

CONCLUSIONS

The most and second most common origins of the cystic artery are the right hepatic artery and the anterior sectional artery. In addition, the origin site of the cystic arteries is influenced by variations of hepatic arteries.

Short-term clinical implications of the accessory left hepatic artery in patients undergoing radical gastrectomy for gastric cancer

Background

To evaluate the prevalence of the accessory left hepatic artery (ALHA; defined as a vessel arising from the left gastric artery, which, together with a typical left hepatic artery, supplies blood to the left lobe of the liver) and its short-term clinical implications in patients undergoing radical gastrectomy for gastric cancer.

Methods

Clinical data of 1173 patients with gastric cancer who underwent laparoscopy-assisted radical gastrectomy were retrospectively analyzed. Groups of patients with and without ALHA were compared to identify differences in intraoperative and postoperative variables and changes in liver function.

Results

Of the 1173 patients, 135 (11.5%) had an ALHA and 1038 (88.5%) did not. There were no significant between-group differences in clinicopathological and intraoperative characteristics, postoperative recovery, and morbidity and mortality rates (P>0.05 each). None of the patients had postoperative symptoms associated with impaired liver function. Glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT) and total bilirubin (TBIL) concentrations were similar preoperatively. TBIL concentrations on postoperative days 1, 3, and 7 were similar (P>0.05), while GOT and GPT activities were higher in the ALHA than in the non-ALHA group on days 1 and 7 (P<0.05), with all three markers similar in the two groups on day 14. In patients without chronic liver disease (CLD), GOT, GPT and TBIL concentrations were similar in patients with and without ALHA; whereas, in patients with CLD, GOT and GPT concentrations on days 1 and 3 and GOT on day 7 were higher in patients with than without ALHA.

Conclusion

ALHA is a common anomaly that was found in 11.5% of patients. It can be safely severed during radical gastrectomy in patients without CLD, but should be left intact in patients with CLD to prevent liver dysfunction. If severed in the latter, the patient should be monitored and liver-protecting therapy may be necessary.

Selective internal radiotherapy (SIRT) of hepatic tumors: how to deal with the cystic artery

PURPOSE

Selective internal radiotherapy (SIRT) with the beta emitter yttrium-90 (Y90) is a rapidly developing therapy option for unresectable liver malignancies. Nontarget irradiation of the gallbladder is a complication of SIRT. Thus, we aimed to assess different strategies to avoid infusion of Y90 into the cystic artery (CA).

METHODS

After hepatic digital subtraction angiography and administration of technetium-99m-labeled human serum albumin ((99)mTc-HSA), 295 patients with primary or secondary liver tumors underwent single-photon emission computed tomography/computed tomography (SPECT/CT). Different measures were taken before repeated Y90 mapping and SIRT to avoid unintended influx into the CA where necessary. Clinical symptoms, including pain, fever, or a positive Murphy sign, were assessed during patient follow-up.

RESULTS

A significant (99)mTc-HSA accumulation in the gallbladder wall (higher (99)mTc-HSA uptake than in normal liver tissue) was seen in 20 patients. The following measures were taken to avoid unintended influx into the CA: temporary/permanent occlusion of the CA with gelfoam (n = 5)/microcoil (n = 1), induction of vasospasm with a microwire (n = 4), or altering catheter position (n = 10). Clinical signs of cholecystitis were observed in only one patient after temporary CA occlusion with gelfoam and were successfully treated by antibiotics. Cholecystectomy was not required for any patient.

CONCLUSION

It is important to identify possible nontarget irradiation of the gallbladder. The risk for radiation-induced cholecystitis can be easily minimized by temporary or permanent CA embolization, vasospasm induction, or altering the catheter position.

Effectiveness of repeat angiographic assessment in patients designated for radioembolization using yttrium-90 microspheres with initial extrahepatic accumulation of technitium-99m macroaggregated albumin: a single center's experience

PURPOSE

To evaluate the efficacy of a workflow consisting of repeat assessment in patients planned for yttrium-90 ((90)Y) radioembolization in case of nontarget visceral technetium-99m ((99m)Tc)-macroaggregated albumin (MAA) accumulation despite initial prophylactic coil embolization of nonhepatic arteries.

MATERIALS AND METHODS

In 341 patients with primary and secondary liver cancer, pretreatment hepatic angiograms, as well as single-photon emission computed tomography coregistered with magnetic resonance imaging scans, were obtained. Extrahepatic tracer deposition was identified in 33 patients (9.7%) necessitating repeat assessment. Images were reviewed to correlate the site of MAA accumulation with causative gastrointestinal vessels, and repeat angiograms served as reference standard.

RESULTS

At repeat angiography, the source of extrahepatic flow was identified and eliminated in 31 of 33 patients (93.9%). In 20 patients (60.6%), successful embolization of nontarget vessels was achieved, in 13 patients (39.4%), MAA was administered more distally. Afterward, extrahepatic MAA deposition was eliminated in 30 patients (90.9%).

CONCLUSION

The algorithm of repeat assessment in case of extrahepatic MAA accumulation has proven highly effective to eliminate extrahepatic shunting, thus decreasing the risk of postradioembolization complications due to inadvertent visceral microsphere deposition.