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

Gallbladder Radiation Protection in SIRT-Quantitative Anatomical Study of Hepatic Vasculature

Introduction: This study was designed to assess quantitatively a safe position of the microcatheter during the SIRT (Selective Internal Radiation Therapy) procedure, in order to minimize the risk of non-target spheres leaking. Materials and Methods: Retrospective analysis of the distance of the tip of the microcatheter from coiled or patent non-target arteries was measured during ^99mTc-MAA work-up procedure. Frequency of extrahepatic leaking during work-up and SIRT procedures was evaluated. Results: There were 85 patients who underwent 98 work-up procedures. There were 64 radioembolizations. There were 44 gastroduodenal, 51 right gastric, and 54 cystic artery embolizations performed. Extrahepatic ^99mTc-MAA leaking was observed in 33 cases: 16 to gallbladder, four to a gastric wall, nine to the duodenum, one to the intestinal wall, and three to the abdominal wall. Leak in ^99mTc-MAA was also related to the presence of additional arteries (p = 0.009). There were 34 proximal and 31 distal to cystic artery ^99mTc-MAA injections resulting in 12 vs. four leaks, respectively (p = 0.039, RR-2.5). Mean distance of the tip of the microcatheter from the origin of the cystic artery was 20 mm (minimum of 2.1 mm and maximum of 53 mm) proximally and 10 mm (minimum 1 mm and maximum 51 mm) distally (ns). Conclusions: Leaking in ^99mTc-MAA (^99mTc - labelled macroaggregated albumin) was related to the presence of additional arteries. Regardless of cystic artery embolization, it is 2.5 times safer to inject microspheres distal to its origin, compared to proximal injection. Cystic artery origin relative to the right hepatic artery division usually necessitates embolization of the former.

Use of C-Arm Cone Beam CT During Hepatic Radioembolization: Protocol Optimization for Extrahepatic Shunting and Parenchymal Enhancement

PURPOSE

To optimize a C-arm computed tomography (CT) protocol for radioembolization (RE), specifically for extrahepatic shunting and parenchymal enhancement.

MATERIALS AND METHODS

A prospective development study was performed per IDEAL recommendations. A literature-based protocol was applied in patients with unresectable and chemorefractory liver malignancies undergoing an angiography before radioembolization. Contrast and scan settings were adjusted stepwise and repeatedly reviewed in a consensus meeting. Afterwards, two independent raters analyzed all scans. A third rater evaluated the SPECT/CT scans as a reference standard for extrahepatic shunting and lack of target segment perfusion.

RESULTS

Fifty scans were obtained in 29 procedures. The first protocol, using a 6 s delay and 10 s scan, showed insufficient parenchymal enhancement. In the second protocol, the delay was determined by timing parenchymal enhancement on DSA power injection (median 8 s, range 4-10 s): enhancement improved, but breathing artifacts increased (from 0 to 27 %). Since the third protocol with a 5 s scan decremented subjective image quality, the second protocol was deemed optimal. Median CNR (range) was 1.7 (0.6-3.2), 2.2 (-1.4-4.0), and 2.1 (-0.3-3.0) for protocol 1, 2, and 3 (p = 0.80). Delineation of perfused segments was possible in 57, 73, and 44 % of scans (p = 0.13). In all C-arm CTs combined, the negative predictive value was 95 % for extrahepatic shunting and 83 % for lack of target segment perfusion.

CONCLUSION

An optimized C-arm CT protocol was developed that can be used to detect extrahepatic shunts and non-perfusion of target segments during RE.

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.

⁹⁰Y Hepatic Radioembolization: An Update on Current Practice and Recent Developments

Radioembolization is an established treatment modality that has been subjected to many improvements over the last decade. Developments are occurring at a high pace, affecting patient selection and treatment. The aim of this review is therefore to provide an overview of current practice, with a focus on recent developments in the field of radioembolization. Several practical issues and recommendations in the application of radioembolization will be discussed, ranging from patient selection to treatment response and future applications.

Why Bundled Payments Could Drive Innovation: An Example From Interventional Oncology

This case study illustrates that in a fee-for-service payment environment, innovation that results in more efficient care may also result in lost revenue.

The role of SPECT/CT in radioembolization of liver tumours

Radioembolization (RE) with (90)Y microspheres is a promising catheter-based therapeutic option for patients with unresectable primary and metastatic liver tumours. Its rationale arises from the dual blood supply of liver tissue through the hepatic artery and the portal vein. Metastatic hepatic tumours measuring >3 mm derive 80 - 100 % of their blood supply from the arterial rather than the portal hepatic circulation. Typically, an angiographic evaluation combined with (99m)Tc-macroaggregated albumin ((99m)Tc-MAA) scan precedes therapy to map the tumour feeding vessels as well as to avoid the inadvertent deposition of microspheres in organs other than the liver. Prior to administration of (99m)Tc-MAA, prophylactic coil embolization of the gastroduodenal artery is recommended to avoid extrahepatic deposition of the microspheres. SPECT/CT allows direct correlation of anatomic and functional information in patients with unresectable liver disease. SPECT/CT is recommended to assess intrahepatic distribution as well as extrahepatic gastrointestinal uptake in these patients. Pretherapeutic SPECT/CT is an important component of treatment planning including catheter positioning and dose finding. A post-therapy bremsstrahlung (BS) scan should follow RE to verify the distribution of the administered tracer. BS SPECT/CT imaging enables better localization and definition of intrahepatic and possible extrahepatic sphere distribution and to a certain degree allows posttreatment dosimetry. In this paper we address the usefulness and significance of SPECT/CT in therapy planning and therapy monitoring of RE.

Clinical and laboratory toxicity after intra-arterial radioembolization with (90)y-microspheres for unresectable liver metastases

OBJECTIVE

To investigate clinical and laboratory toxicity in patients with unresectable liver metastases, treated with yttrium-90 radioembolization ((90)Y-RE).

METHODS

Patients with liver metastases treated with (90)Y-RE, between February 1(st) 2009 and March 31(st) 2012, were included in this study. Clinical toxicity assessment was based on the reporting in patient's charts. Laboratory investigations at baseline and during a four-month follow-up were used to assess laboratory toxicity according to the Common Terminology Criteria for Adverse Events version 4.02. The occurrence of grade 3-4 laboratory toxicity was stratified according to treatment strategy (whole liver treatment in one session versus sequential sessions). Response assessment was performed at the level of target lesions, whole liver and overall response in accordance with RECIST 1.1 at 3- and 6 months post-treatment. Median time to progression (TTP) and overall survival were calculated by Kaplan-Meier analysis.

RESULTS

A total of 59 patients, with liver metastases from colorectal cancer (n = 30), neuroendocrine tumors (NET) (n = 6) and other primary tumors (n = 23) were included. Clinical toxicity after (90)Y-RE treatment was confined to grade 1-2 events, predominantly post-embolization symptoms. No grade 3-4 clinical toxicity was observed, whereas laboratory toxicity grade 3-4 was observed in 38% of patients. Whole liver treatment in one session was not associated with increased laboratory toxicity. Three-months disease control rates for target lesions, whole liver and overall response were 35%, 21% and 19% respectively. Median TTP was 6.2 months for target lesions, 3.3 months for the whole liver and 3.0 months for overall response. Median overall survival was 8.9 months.

CONCLUSION

The risk of severe complications or grade 3-4 clinical toxicity in patients with liver metastases of various primary tumors undergoing (90)Y-RE is low. In contrast, laboratory toxicity grade 3-4 can be expected to occur in more than one-third of patients without any clinical signs of radiation induced liver disease.

Usefulness and pitfalls of MAA SPECT/CT in identifying digestive extrahepatic uptake when planning liver radioembolization

Purpose

Identifying gastroduodenal uptake of ^99mTc-macroaggregated albumin (MAA), which is associated with an increased risk of ulcer disease, is a crucial part of the therapeutic management of patients undergoing radioembolization for liver tumours. Given this context, the use of MAA single photon emission computed tomography (SPECT)/CT may be essential, but the procedure has still not been thoroughly evaluated. The aim of this retrospective study was to determine the effectiveness of MAA SPECT/CT in identifying digestive extrahepatic uptake, while determining potential diagnostic pitfalls.

Methods

Overall, 139 MAA SPECT/CT scans were performed on 103 patients with different hepatic tumour types. Patients were followed up for at least 6 months according to standard requirements.

Results

Digestive, or digestive-like, uptake other than free pertechnetate was identified in 5.7% of cases using planar imaging and in 36.6% of cases using SPECT/CT. Uptake sites identified by SPECT/CT included the gastroduodenal region (3.6%), gall bladder (12.2%), portal vein thrombosis (6.5%), hepatic artery (6.5%), coil embolization site (2.1%) as well as falciform artery (5.0%). For 2.1% of explorations, a coregistration error between SPECT and CT imaging could have led to a false diagnosis by erroneously attributing an uptake site to the stomach or gall bladder, when the uptake actually occurred in the liver.

Conclusion

SPECT/CT is more efficacious than planar imaging in identifying digestive extrahepatic uptake sites, with extrahepatic uptake observed in one third of scans using the former procedure. However, more than half of the uptake sites in our study were vascular in nature, without therapeutic implications. The risk of coregistration errors must also be kept in mind.