Safety and Efficacy Assessment of Flow Redistribution by Occlusion of Intrahepatic Vessels Prior to Radioembolization in the Treatment of Liver Tumors

Abstract

We evaluated the feasibility, safety, and efficacy of radioembolization (administered from one or two vascular points) after the redistribution of arterial blood flow in the liver in patients with hepatic neoplasms and arterial anatomic peculiarities (AAP). Twenty-four patients with liver neoplasms and AAP (graded according to Michel's classification) were included in the study. During pretreatment angiographic planning, all extrahepatic vessels that could feed the tumor were embolized and the intrahepatic vessels occluded in order to redistribute blood flow. The distribution of microspheres was initially assessed by using technetium-99m-labeled macroaggregated albumin ((99m)Tc-MAA) from one of two vascular points before the administration of yttrium-90 ((90)Y)-radiolabeled resin microspheres. Perfusion of lesions situated in the redistributed segments (L-RS) and nonredistributed segments (L-NRS) were compared by assessing the distribution of (99m)Tc-MAA by SPECT/CT. Perfusion was graded as normal, reduced, or absent. (90)Y resin microspheres were then injected from the same arterial sites as (99m)Tc-MAA and the tumor response recorded 3 months later. The tumor response in L-RS was compared with that in L-NRS and graded as better, similar, or worse. Among 11 patients with type I AAP in whom mainly vessels in segments I-III or IV were occluded, perfusion of L-RS was graded as similar (n = 7) or reduced (n = 4). Among the remaining 13 patients with AAP types III (n = 3), V (n = 4), VIII (n = 3), and others (n = 3) in which aberrant arteries were occluded, perfusion of L-RS was graded as similar (n = 9), reduced (n = 3), or absent (n = 1). Overall, (99m)Tc-MAA was present in the L-RS of 95.8% patients and the distribution of (99m)Tc-MAA in L-RS and L-NRS were graded as similar in 66.6% of patients. Compared with lesions in the L-NRS, tumor response in L-RS was similar in 23 cases and worse in 1 case. No complications were recorded after the administration of (90)Y resin microspheres. Redistribution of flow in L-RS is feasible and enables a safe and effective delivery of (90)Y resin microspheres that are able to be distributed via intrahepatic collaterals and access the microvasculature of L-RS.

The Relation Between Perfusion Pattern of Hepatic Artery Perfusion Scintigraphy and Response to Y-90 Microsphere Therapy

“…Smaller tumours displayed diffuse and intense uptake of 99m-Tc MAA. This finding supports the literature stating that HAPS can be used to evaluate not only the extrahepatic shunting but also tumour vasculature in order to predict therapy response (7,8). …”

“…In another study, the tumours’ perfusion change was evaluated by HAPS perfusion pattern after a reperfusion procedure i.e. occlusion of extrahepatic vessels, and relation between perfusion pattern change and tumour response was evaluated (8). The authors stated that HAPS revealed the change in perfusion after redistribution during the angiographic workup, and this way they delivered treatment to the whole tumour volume accurately (8).…”

“…occlusion of extrahepatic vessels, and relation between perfusion pattern change and tumour response was evaluated (8). The authors stated that HAPS revealed the change in perfusion after redistribution during the angiographic workup, and this way they delivered treatment to the whole tumour volume accurately (8). In the present study, the perfusion pattern was assessed visually and a heterogeneous perfusion pattern was observed especially for liver lesions with greater diameter and necrotic centre (Figure 1).…”

Research Reporting Standards for Radioembolization of Hepatic Malignancies

“…The meticulous mapping of the vascular anatomy helps the interventional radiologist performing the procedure to (i) identify the vascular supply of the tumor and (ii) identify and coil-embolize vessels that may lead to aberrant deposition of the radioembolic material. There is a new concept of flow redistribution (ie, occlusion intrahepatic vessels before radioembolization to cause redistribution of flow) that is being advocated by certain centers; if this technique is used, it should be reported (38,41). Therapy control is defined as the intraprocedural adjustments to increase safety/efficacy of the procedure (25).…”

Hepatic Arterial Configuration in Relation to the Segmental Anatomy of the Liver; Observations on MDCT and DSA Relevant to Radioembolization Treatment

“…For the administration in branches at high risk for nontarget embolization, such as aberrant hepatic arteries originating from the LGA, an antireflux catheter, such as the Surefire Infusion System Ò (Surefire Medical Inc., Westminster, CO), may be used [33]. Another strategy is to coil embolize aberrant hepatic arteries to induce a redistribution of blood flow through small intrahepatic collateral pathways and administer microspheres in the hepatic artery that took over the coiled artery's vascular territory, resulting in a simplified and safe administration [34,35].…”