M. Horikawa

Embolization of Arteriovenous Malformations: Effect of Flow Control and Composition of n-Butyl-2 Cyanoacrylate and Iodized Oil Mixtures with and without Ethanol in an in Vitro Model

Purpose To elucidate the effect of flow control (ie, balloon occlusion) and the composition of various mixtures of n-butyl-2 cyanoacrylate (NBCA) and iodized oil, with and without the addition of ethanol, for the treatment of arteriovenous malformations in an in vitro model. Materials and Methods A simulation circuit device that featured an artificial nidus was filled with heparinized swine blood obtained during exsanguination from another Institutional Animal Care and Use Committee-approved protocol and was constructed to generate pulsatile flow. Mixtures of NBCA and iodized oil (NL) at a 1:1 ratio (NL 1:1); NL and ethanol (NLE) at a 1:1:3 ratio (NLE 1:1:3) with or without flow control; and NL at 1:3, 1:5, and 1:10 ratios without flow control were injected six times each for a total of 42 trials. Embolization was classified as complete filling, proximal occlusion, pass through, or distal overpenetration after occlusion balloon deflation, and the trial results were compared. The results of the embolization test were evaluated by using the Fisher exact probability test to compare optimal and suboptimal embolization groups. Results NLE 1:1:3 with flow control completely filled the nidus in all six trials. NL 1:1 delivered with flow control achieved complete nidus filling in three of six injections, as did the NL 1:5 ratio trial without flow control. Complete embolization with NLE 1:1:3 with flow control was more feasible to achieve complete nidus filling than was NL 1:1 with flow control or NL 1:5 without flow control, although there was no statically significant difference (all, P = .09). None of the other mixtures produced complete embolization. Conclusion NLE 1:1:3 showed consistent and reproducible complete embolization with flow control and was stable after balloon deflation, making it an acceptable material for embolization in an in vitro arteriovenous malformation model. Further study should be performed before the NLE 1:1:3 mixture is used in routine clinical practice. (©) RSNA, 2015.

Development of Conventional Transarterial Chemoembolization for Hepatocellular Carcinomas in Japan: Historical, Strategic, and Technical Review

OBJECTIVE This article reviews the development of transarterial chemoembolization (TACE) in Japan, particularly ethiodized oil-based conventional TACE, from historical, strategic, and technical points of view. We also present the current status of standardized conventional TACE. CONCLUSION Conventional TACE has been developed toward a more-selective and hemodynamic-conscious method, along with technical innovation and knowledge accumulation. Standardization of this method is necessary for further scientific evaluation.

Arteriopathy after transarterial chemo-lipiodolization for hepatocellular carcinoma

OBJECTIVES The purpose of this study was to investigate the incidence of and the risk factors for arteriopathy in hepatic arteries after transarterial chemo-lipiodolization in patients with hepatocellular carcinoma and the subsequent treatment strategy changes due to arteriopathy. PATIENTS AND METHODS A total of 365 arteries in 167 patients (126 men and 41 women; mean age, 60.4±15.0 [SD] years [range: 18-87 years]) were evaluated for the development of arteriopathy after chemo-lipiodolization with epirubicin- or doxorubicin-Lipiodol® emulsion. The development of arteriopathy after chemo-lipiodolization was assessed on arteriograms performed during subsequent transarterial treatments. The treatment strategy changes due to arteriopathy, including change in the chemo-lipiodolization method and the application of alternative therapies was also investigated. Univariate and multivariate binary logistic regression models were used to identify risk factors for arteriopathy and subsequent treatment strategy change. RESULTS One hundred two (27.9%) arteriopathies were detected in 62/167 (37.1%) patients (45 men, 17 women) with a mean age of 63.3±7.1 [SD] years (age range, 50-86 years). The incidence of arteriopathy was highly patient dependent, demonstrating significant correlation in a fully-adjusted multivariate regression model (P<0.0001). Multivariate-adjusted regression analysis with adjustment for the patient effect showed a statistically significant association of super-selective chemo-lipiodolization (P=0.003) with the incidence of arteriopathy. Thirty of the 102 arteriopathies (29.4%) caused a change in treatment strategy. No factors were found to be significantly associated with the treatment strategy change. CONCLUSION The incidence of arteriopathy after chemo-lipiodolization is 27.9%. Among them, 29.4% result in a change in treatment strategy.

Embolization of the Thoracic Duct by Direct Injection of N-Butyl-2-Cyanoacrylate Glue via a Puncture Needle

PurposeTo report embolization of the thoracic duct by direct injection of N-butyl-2-cyanoacrylate (NBCA) glue via a puncture needle.Materials and MethodsTwo cases of high output chylothorax were successfully treated with direct injection of N-butyl-2-cyanoacrylate (NBCA) glue via a puncture needle. In them, conventional thoracic duct embolization (TDE) was attempted, but the cisterna chyli was absent on intranodal lymphangiography, and probably for this reason catheterization of the thoracic duct was unsuccessful. Contrast material injection via a puncture needle, however, clearly showed a leak from the thoracic duct, prompting us to attempt embolization of the thoracic duct by direct injection of NBCA glue via the needle.ResultsThoracic duct embolization by direct injection of NBCA glue via a puncture needle was technically successful in both patients. No minor or major complication occurred. Both patients disappeared chylothorax after this treatment.ConclusionThis embolization method can be useful for treatment of chylothorax when conventional TDE is not achievable.

VIDEO: Technique to Restrict the Gore Viatorr Stent-Graft for TIPS Reduction

OBJECTIVE The Viatorr stent-graft (W. L. Gore and Associates), specifically made for transjugular intrahepatic portosystemic shunt (TIPS) creation, has significantly improved TIPS patency compared with bare metal stents. Post-TIPS hepatic encephalopathy (HE), however, remains relatively common after TIPS creation. We describe a technique to secondarily restrict a Viatorr stent-graft to treat post-TIPS refractory HE and maintain use of the Viatorr device. CONCLUSION We show a simple technique to modify the Viatorr stent-graft for TIPS reduction.

Baseline tumor Lipiodol uptake after transarterial chemoembolization for hepatocellular carcinoma: identification of a threshold value predicting tumor recurrence

Abstract Background The aim of the study was to evaluate the association between baseline Lipiodol uptake in hepatocellular carcinoma (HCC) after transarterial chemoembolization (TACE) with early tumor recurrence, and to identify a threshold baseline uptake value predicting tumor response. Patients and methods A single-institution retrospective database of HCC treated with Lipiodol-TACE was reviewed. Forty-six tumors in 30 patients treated with a Lipiodol-chemotherapy emulsion and no additional particle embolization were included. Baseline Lipiodol uptake was measured as the mean Hounsfield units (HU) on a CT within one week after TACE. Washout rate was calculated dividing the difference in HU between the baseline CT and follow-up CT by time (HU/month). Cox proportional hazard models were used to correlate baseline Lipiodol uptake and other variables with tumor response. A receiver operating characteristic (ROC) curve was used to identify the optimal threshold for baseline Lipiodol uptake predicting tumor response. Results During the follow-up period (mean 5.6 months), 19 (41.3%) tumors recurred (mean time to recurrence = 3.6 months). In a multivariate model, low baseline Lipiodol uptake and higher washout rate were significant predictors of early tumor recurrence (P = 0.001 and < 0.0001, respectively). On ROC analysis, a threshold Lipiodol uptake of 270.2 HU was significantly associated with tumor response (95% sensitivity, 93% specificity). Conclusions Baseline Lipiodol uptake and washout rate on follow-up were independent predictors of early tumor recurrence. A threshold value of baseline Lipiodol uptake > 270.2 HU was highly sensitive and specific for tumor response. These findings may prove useful for determining subsequent treatment strategies after Lipiodol TACE.

Mechanisms of Günther Tulip filter tilting during transfemoral placement

OBJECTIVE The purpose of this study was to characterize the mechanisms of Günther Tulip filter (GTF) tilting during transfemoral placement in an experimental model with further validation in a clinical series. MATERIALS AND METHODS In an experimental study, 120 GTF placements in an inferior vena cava (IVC) model were performed using 6 configurations of pre-deployment filter position. The angle between the pre-deployment filter axis and IVC axis, and the proximity of the constrained filter legs to IVC wall prior to deployment were evaluated. The association of those pre-deployment factors with post-deployment filter tilting was analyzed. The association noted in the experimental study was then evaluated in a retrospective clinical series of 21 patients. RESULTS In the experimental study, there was a significant association between the pre-deployment angle and post-deployment filter tilting (P<0.0001). With a low pre-deployment angle (≤5°), a significant association was noted between filter tilting and the proximity of the constrained filter legs to the far IVC wall (P=0.001). In a retrospective clinical study, a significant association between the pre-deployment angle and post-deployment filter tilting was also noted with a linear regression model (P=0.026). CONCLUSION Significant association of the pre-deployment angle with post-deployment GTF tilting was shown in both the experimental and clinical studies. The experimental study also showed that proximity of filter legs is relevant when pre-deployment angle is small. Addressing these factors may result in a lower incidence of filter tilting.

Practical Tantalum Coating of Microspheres for Experimental Visualization under Fluoroscopy and CT

The present report describes a simple technique for tantalum coating of microspheres for visualization by fluoroscopy and computed tomography (CT). Spherical microspheres were soaked with Ta powder under different conditions and microscopically evaluated for Ta-coating quality by assessing bound and unbound Ta. For 100-300-µm Embosphere particles, soaking with 0.05 mL Ta powder for 30 minutes and centrifugation at 500 rpm produced optimal coating. Optimized microspheres were injected in swine renal arteries and assessed by fluoroscopy and micro-CT for the opacification of segmental, arcuate, and interlobular arteries. This practical method can be used for experimental studies with commonly available microspheres.