Tracking and navigation of a microswarm under laser speckle contrast imaging for targeted delivery.

Micro/nanorobotic swarms consisting of numerous tiny building blocks show great potential in biomedical applications because of their collective active delivery ability, enhanced imaging contrast, and environment-adaptive capability. However, in vivo real-time imaging and tracking of micro/nanorobotic swarms remain a challenge, considering the limited imaging size and spatial-temporal resolution of current imaging modalities. Here, we propose a strategy that enables real-time tracking and navigation of a microswarm in stagnant and flowing blood environments by using laser speckle contrast imaging (LSCI), featuring full-field imaging, high temporal-spatial resolution, and noninvasiveness. The change in dynamic convection induced by the microswarm can be quantitatively investigated by analyzing the perfusion unit (PU) distribution, offering an alternative approach to investigate the swarm behavior and its interaction with various blood environments. Both the microswarm and surrounding environment were monitored and imaged by LSCI in real time, and the images were further analyzed for simultaneous swarm tracking and navigation in the complex vascular system. Moreover, our strategy realized real-time tracking and delivery of a microswarm in vivo, showing promising potential for LSCI-guided active delivery of microswarm in the vascular system.

tPA-anchored nanorobots for in vivo arterial recanalization at submillimeter-scale segments.

Micro/nanorobots provide a promising approach for intravascular therapy with high precision. However, blood vessel is a highly complex system, and performing interventional therapy in those submillimeter segments remains challenging. While micro/nanorobots can enter submillimeter segments, they may still comprise nonbiodegradable parts, posing a considerable challenge for post-use removal. Here, we developed a retrievable magnetic colloidal microswarm, composed of tPA-anchored Fe3O4@mSiO2 nanorobots (tPA-nbots), to archive tPA-mediated thrombolysis under balloon catheter-assisted magnetic actuation with x-ray fluoroscopy imaging system (CMAFIS). By deploying tPA-nbot transcatheter to the vicinity of the thrombus, the tPA-nbot microswarms were magnetically actuated to the blood clot at the submillimeter vessels with high precision. After thrombolysis, the tPA-nbots can be retrieved via the CMAFIS, as demonstrated in ex vivo organ of human placenta and in vivo carotid artery of rabbit. The proposed colloidal microswarm provides a promising robotic tool with high spatial precision for enhanced thrombolysis with low side effects.

The Hong Kong consensus statements on unresectable hepatocellular carcinoma: narrative review and update for 2021.

Background and Objective: Hong Kong, like many parts of Asia, faces a high burden of hepatocellular carcinoma (HCC) caused by high endemic rates of hepatitis B virus infection. Hong Kong clinicians have developed a high level of expertise in HCC treatment across surgical, transarterial, ablative, radiotherapeutic and systemic modalities. This publication summarizes the latest evidence-based recommendations on how these modalities should be used. Methods: In two meetings held in 2020, a multidisciplinary panel of surgeons, oncologists and interventional radiologists performed a narrative review of evidence on the management of HCC, with an emphasis on treatment of HCC not amenable to surgical resection. Close attention was paid to new evidence published since the previous version of these statements in 2018. Key Content and Findings: The expert panel has formulated 60 consensus statements to guide the staging and treatment of unresectable HCC. Since the previous version of these statements, considerable additions have been made to the recommendations on use of targeted therapies and immunotherapies because of the large volume of new evidence. Conclusions: Our consensus statements offer guidance on how to select HCC patients for surgical or non-surgical treatment and for choosing among non-surgical modalities for patients who are not candidates for resection. In particular, there is a need for more evidence to aid physicians in the selection of second-line systemic therapies, as currently most data are limited to patients with disease progression on first-line sorafenib.

Swarming self-adhesive microgels enabled aneurysm on-demand embolization in physiological blood flow.

The recent rise of swarming microrobotics offers great promise in the revolution of minimally invasive embolization procedure for treating aneurysm. However, targeted embolization treatment of aneurysm using microrobots has significant challenges in the delivery capability and filling controllability. Here, we develop an interventional catheterization-integrated swarming microrobotic platform for aneurysm on-demand embolization in physiological blood flow. A pH-responsive self-healing hydrogel doped with magnetic and imaging agents is developed as the embolic microgels, which enables long-term self-adhesion under biological condition in a controllable manner. The embolization strategy is initiated by catheter-assisted deployment of swarming microgels, followed by the application of external magnetic field for targeted aggregation of microrobots into aneurysm sac under the real-time guidance of ultrasound and fluoroscopy imaging. Mild acidic stimulus is applied to trigger the welding of microgels with satisfactory bio-/hemocompatibility and physical stability and realize complete embolization. Our work presents a promising connection between the design and control of microrobotic swarms toward practical applications in dynamic environments.

Uncertainty-aware self-supervised neural network for liverT1ρmapping with relaxation constraint.

Objective.T1ρmapping is a promising quantitative MRI technique for the non-invasive assessment of tissue properties. Learning-based approaches can mapT1ρfrom a reduced number ofT1ρweighted images but requires significant amounts of high-quality training data. Moreover, existing methods do not provide the confidence level of theT1ρestimation. We aim to develop a learning-based liverT1ρmapping approach that can mapT1ρwith a reduced number of images and provide uncertainty estimation.Approach. We proposed a self-supervised neural network that learns aT1ρmapping using the relaxation constraint in the learning process. Epistemic uncertainty and aleatoric uncertainty are modelled for theT1ρquantification network to provide a Bayesian confidence estimation of theT1ρmapping. The uncertainty estimation can also regularize the model to prevent it from learning imperfect data. Main results. We conducted experiments onT1ρdata collected from 52 patients with non-alcoholic fatty liver disease. The results showed that when only collecting twoT1ρ-weighted images, our method outperformed the existing methods forT1ρquantification of the liver. Our uncertainty estimation can further regularize the model to improve the performance of the model and it is consistent with the confidence level of liverT1ρvalues.Significance. Our method demonstrates the potential for accelerating theT1ρmapping of the liver by using a reduced number of images. It simultaneously provides uncertainty ofT1ρquantification which is desirable in clinical applications.

Selective Internal Radiation Therapy with Yttrium-90 Resin Microspheres Followed by Gemcitabine plus Cisplatin for Unresectable Intrahepatic Cholangiocarcinoma: A Phase 2 Single-Arm Multicenter Clinical Trial.

Introduction: This investigator-initiated clinical trial aims to study the efficacy and safety of administering selective internal radiation therapy with resin yttrium-90 microspheres (SIRT) followed by standard chemotherapy in unresectable intrahepatic cholangiocarcinoma (ICC). Methods: A phase 2 single-arm multicenter study was conducted in patients with unresectable ICC (NCT02167711). SIRT was administered at dose of 120 Gy targeted at tumor followed by commencement of gemcitabine 1,000 mg/m2 and cisplatin 25 mg/m2 on days one and eight of a 21-day cycle. The primary endpoint was overall survival (OS), and the secondary endpoints include progression-free survival (PFS), response rate according to Response Evaluation Criteria in solid tumors 1.1, toxicity, and time from SIRT to commencement of chemotherapy. Results: Total 31 patients were screened and twenty-four were recruited. All patients completed SIRT and 16 of them underwent subsequent chemotherapy. The median cycle of chemotherapy was 5 (range: 1-8). The median OS was 13.6 months (95% CI: 5.4-21.6) for the intent-to-treat population. Among 16 patients undergoing chemotherapy, the median OS was 21.6 months (95% CI: 7.3-25.2) and the median PFS was 9 months (95% CI: 3.2-13.1). The response rate was 25% (95% CI: 3.8-46.2%), and the disease control rate was 75% (95% CI: 53.8-96.2%). No new safety signal was observed, with fewer than 10% of patients suffering from grade 3 or higher treatment-related adverse events. The median time from SIRT to chemotherapy was 29 (range: 7-42) days. Eight patients could not receive chemotherapy due to rapid progressive disease (n = 4), underlying treatment unrelated comorbidities (n = 2), and withdrawal of consent due to personal reasons (n = 2). Conclusions: Treatment of SIRT followed by standard gemcitabine and cisplatin chemotherapy is feasible and effective for unresectable ICC. Further studies are required to study the optimal sequence of SIRT and chemotherapy.

PHIL and Squid Embolization of Cerebral Arteriovenous Malformation: A Retrospective Case Series of 23 Patients.

Precipitating hydrophobic injectable liquid (PHIL; MicroVention, Aliso Viejo, CA, USA) and Squid (Balt, Irvine, CA, USA) are 2 newer liquid embolic agents used in endovascular embolization of cerebral arteriovenous malformation (AVM). This study aims to investigate and compare the effectiveness and safety profile of the 2 newer liquid embolic agents in the embolization of cerebral AVM. This is a retrospective study on all patients diagnosed with cerebral AVM undergoing endovascular embolization with liquid embolic agents PHIL and Squid admitted to the Division of Neurosurgery, Department of Surgery in Prince of Wales Hospital from January 2014 to June 2021. Twenty-three patients with cerebral AVM were treated with 34 sessions of endovascular embolization with either PHIL or Squid (17 sessions each) liquid embolic agents with a male to female ratio of 2.3:1 (male 16; female 7) and mean age of 44.6 (range, 12 to 67). The mean total nidus obliteration rate per session was 57% (range, 5% to 100%). Twenty-one patients (91.3%) received further embolization, stereotactic radiosurgery, or surgical excision after initial endovascular embolization. There were 2 morbidities (1 neurological and 1 non-neurological, 6%) and no mortalities (0%). All patients had static or improvement in modified Rankin Scale at 3 to 6 months at discharge. PHIL and Squid are effective and safe liquid embolic agents for endovascular embolization of cerebral AVM, achieving satisfactory nidal obliteration rates and patient functional outcomes.

Blood Flow Diversion Within Hepatocellular Carcinoma (HCC) after Selective Occlusion of Feeding Arteries (SOFA) and Feasibility of Utilizing the SOFA Technique in Transarterial Chemoembolization (SOFA-TACE).

PURPOSE: Arterial feeders supplying a hepatocellular carcinoma are known to be interconnected through the sinusoid-like tumor vasculature. It was observed angiographically that when one of the feeders is selectively catheterized for drug delivery in transarterial chemoembolization (TACE), the whole tumor vasculature will be filled up, if the arterial inflow from all the other feeders is temporarily arrested with selective occlusion of feeding arteries (SOFA) using an additional catheter (balloon catheter). The feasibility of using the SOFA technique in TACE (SOFA-TACE) is discussed. MATERIALS AND METHODS: In this prospective, monocentric feasibility study, with informed consent obtained, 8 consecutive patients of median age 64.5 years (60-68.8) and tumor dimension 4.7 cm (3.2-6.1), having specific tumor features (solitary, hypervascularity, well-defined, ≤ 7 cm, multiple tumor feeders), received SOFA-TACE using ethiodized oil-cisplatin suspension. Tumor response was assessed with 3-monthly CT using modified RECIST. RESULTS: A single tumor feeder was catheterized for drug delivery (8 cases). All other tumor feeders were successfully occluded with a balloon at one site (8 cases). Complete filling of the vasculature of the whole tumor was achieved in 7 of 8 cases with the SOFA technique as shown on arteriogram and CT, except in a case with an intratumoral septum. There was no complication. Surveillance CT (median 25 months, range 22-28) showed complete response in all cases. CONCLUSION: SOFA-TACE is feasible with reasonable safety and favorable treatment outcome; it may be a valuable technical option that may facilitate the procedures of selective TACE in technically challenging cases.

Comparison of Chemoembolization, Radioembolization, and Transarterial Ethanol Ablation for Huge Hepatocellular Carcinoma (≥ 10 cm) in Tumour Response and Long-Term Survival Outcome.

PURPOSE: To compare transarterial chemoembolization (TACE), transarterial radioembolization using Yttrium-90 (TARE), and transarterial ethanol ablation (TEA) for huge hepatocellular carcinoma (HCC) in treatment responses and long-term survival outcomes. MATERIALS AND METHODS: In this retrospective study approved by institutional committee, inclusion criteria were tumour ≥ 10 cm, newly diagnosed, treatment naïve, Child A, Performance Score 0 or 1, no venous invasion or extrahepatic disease on contrast-enhanced CT or MRI. There were 107 patients (Supportive Care [SC] 17, TACE 54, TARE 17, TEA 19). Survival outcomes of SC and TACE were compared (TACE selected as benchmark for transarterial treatments). Tumour response and overall survival (OS) of the three groups were compared. RESULTS: OS of TACE (vs. SC) was significantly longer (9.9 [5.9, 24.1] months versus 2.8 [1.5, 10.2], p = 0.001). Complete response of TEA was significantly better (TEA 10/19 [52.6%] versus TARE 2/17 [12.5%], p = 0.013, versus TACE 9/54 [16.7%], p = 0.002). OS of TEA (vs. TACE) was significantly longer (21.6 [12, 41] months versus 9.9 [5.9, 24.1], p = 0.014, hazard ratio 0.6 (0.3, 1). OS of TEA (vs. TARE) was longer (21.6 [12, 41] months versus 11.9 [7, 28.7], p = 0.082, hazard ratio 0.6 (0.3, 1.3) in favour of TEA). CONCLUSION: In patients with huge HCC, transarterial treatment as represented by TACE had a survival benefit over supportive care. In this retrospective analysis, TEA was associated with better tumour response and survival outcome as compared to TACE or TARE; therefore, transarterial treatment could be useful for prolonging patient survival, and TEA could be a preferred option.

Comparison of Survival Outcomes in Transarterial Ethanol Ablation and Liver Resection for Solitary Hepatocellular Carcinoma ≤ 5 cm in Patients Stratified by Liver Function.

PURPOSE: To compare the survival outcomes of patients treated with transarterial ethanol ablation (TEA) with those treated with liver resection (LR) for solitary HCC less than 5 cm in diameter, in patients stratified according to liver function using ALBI grade. MATERIALS AND METHODS: This retrospective study approved by the Institutional Committee included all treatment-naïve patients with solitary HCC (≤ 5 cm) and Child-Pugh score 5, and who had received TEA (33 patients) or LR (192 patients) between 2004 and 2012. Treatment outcomes were compared between patients treated with TEA and LR after a period of at least 7 years of follow-up. Comparison was repeated for those patients with ALBI grade 2 or 3. RESULTS: Both overall survival (OS, months) and recurrence-free survival (RFS months) were significantly longer in the LR group (OS: LR 129.7[119.5, 140], TEA 69.1[55.9, 82.3], P < 0.0001; RFS: LR 91.3[43.5, 139.1], TEA 13.8 [11, 16.5], P < 0.0001). In patients with ALBI grade 2 or 3, there was no significant difference between the groups in OS or RFS (OS: LR 43.1[0, 91.2], TEA 55.4 [43.7, 67.2], P = 0.65; RFS: LR 17.8 [11.4, 24.2], TEA 11.9 [6.7, 17.1], P = 0.132). Transient epigastric discomfort and low-grade fever without consequence occurred in 8 patients (8/33 or 24.2%) in the TEA group. CONCLUSION: The overall survival after LR for HCCs ≤ 5 cm was superior to that after TEA but similar when compared in patients with ALBI grade 2 or 3, the ALBI grade is useful for patient selection for TEA or LR for HCCs ≤ 5 cm.

Consensus of Minimally Invasive and Multidisciplinary Comprehensive Treatment for Hepatocellular Carcinoma - 2020 Guangzhou Recommendations.

In China, the majority of patients with hepatocellular carcinoma (HCC) result from long-term infection of hepatitis B. Pathologically, HCC is characterized by rich blood supply, multicentric origins, early vascular invasion and intrahepatic metastasis. Therefore, HCC is not a local disease but a systemic disease at the beginning of its occurrence. For this reason, a comprehensive treatment strategy should be adopted in the management of HCC, including local treatments (such as surgical resection, radiofrequency ablation, microwave ablation, chemical ablation and cryoablation, etc.), organ-level treatments [such as transcatheter arterial infusion of chemotherapy and transcatheter arterial chemoembolization (TACE)], and systemic treatments (such as immunotherapy, antiviral therapy and molecular targeted therapy, etc.). This consensus sets forth the minimally-invasive and multidisciplinary comprehensive guideline of HCC, focusing on the following eight aspects (1) using hepaticarteriography, CT hepatic arteriography (CTHA), CT arterial portography (CTAP), lipiodol CT (Lp-CT), TACE-CT to find the intrahepatic lesion and make precise staging (2) TACE combined with ablation or ablation as the first choice of treatment for early stage or small HCC, while other therapies are considered only when ablation is not applicable (3) infiltrating HCC should be regarded as an independent subtype of HCC (4) minimally-invasive comprehensive treatment could be adopted in treating metastatic lymph nodes (5) multi-level subdivision of M-staging should be used for individualized treatment and predicting prognosis (6) HCC with severe hepatic decompensation is the only candidate criterion for liver transplantation (7) bio-immunotherapy, traditional Chinese medicine therapy, antiviral therapy, and psychosocial and psychopharmacological interventions should be advocated through the whole course of HCC treatment (8) implementation of multicenter randomized controlled trials of minimally-invasive therapy versus surgery for early and intermediate stage HCC is recommended.

Ultrasound Doppler-guided real-time navigation of a magnetic microswarm for active endovascular delivery.

Swarming micro/nanorobots offer great promise in performing targeted delivery inside diverse hard-to-reach environments. However, swarm navigation in dynamic environments challenges delivery capability and real-time swarm localization. Here, we report a strategy to navigate a nanoparticle microswarm in real time under ultrasound Doppler imaging guidance for active endovascular delivery. A magnetic microswarm was formed and navigated near the boundary of vessels, where the reduced drag of blood flow and strong interactions between nanoparticles enable upstream and downstream navigation in flowing blood (mean velocity up to 40.8 mm/s). The microswarm-induced three-dimensional blood flow enables Doppler imaging from multiple viewing configurations and real-time tracking in different environments (i.e., stagnant, flowing blood, and pulsatile flow). We also demonstrate the ultrasound Doppler-guided swarm formation and navigation in the porcine coronary artery ex vivo. Our strategy presents a promising connection between swarm control and real-time imaging of microrobotic swarms for localized delivery in dynamic environments.

LPAQR-Net: Efficient Vertebra Segmentation From Biplanar Whole-Spine Radiographs.

Vertebra segmentation from biplanar whole-spine radiographs is highly demanded in the quantitative assessment of scoliosis and the resultant sagittal deformities. However, automatic vertebra segmentation from the radiographs is extremely challenging due to the low contrast, blended boundaries, and superimposition of many layers, especially in the sagittal plane. To alleviate these problems, we propose a lightweight pyramid attention quick refinement network (LPAQR-Net) for efficient and accurate vertebra segmentation. The LPAQR-Net consists of three components: (1) a lightweight backbone network (LB-Net) to prune network parameters and memory footprints to strike an optimal balance between speed and accuracy, (2) a series of global attention refinement (GAR) modules to selectively reuse low-level features to facilitate the feature refinement, and (3) an attention-based atrous spatial pyramid pooling (A-ASPP) module to extract weighted pyramid contexts to improve the segmentation of blurred vertebrae. Moreover, the multi-class training strategy is employed to alleviate the over-segmentation of adjacent vertebrae. Evaluation results on both frontal and lateral radiographs of 332 AIS patients show our method achieves accurate vertebra segmentation with significant reductions in inference time and computational demands compared to the state-of-the-art. Meanwhile, results on the public AASCE2019 dataset also demonstrate the good generalization ability of our model. It is the first attempt to explore the lightweight network for vertebra segmentation from biplanar whole-spine radiographs. It simulates radiologists gathering nearby contexts for accurate and robust vertebra boundary inference. The method can provide efficient and accurate vertebra segmentation for clinicians to perform a fast and reproducible spinal deformity evaluation.

Timing and Outcomes of Intracranial Stenting in the Post-SAMMPRIS Era: A Systematic Review.

Objective: To investigate the impact of timing on the safety and efficacy of stenting for ICAS, we reviewed high-volume randomized controlled trials or prospective cohort studies of stenting for intracranial atherosclerotic artery stenosis (ICAS) after the SAMMPRIS trial. Methods: We included randomized controlled trials or prospective cohort studies since 2011 (the publication of the SAMMPRIS trial), evaluating the outcomes of intracranial stenting for ICAS patients. The primary outcomes were perioperative and 1-year stroke or death rate. The interaction of timing and outcomes were shown on trend plots. Overall meta-analysis and subgroup analysis by timing of intracranial stenting were conducted. Results: Fourteen studies with a total of 1,950 patients were included. The perioperative and post-operative stroke or death rates decreased with the time of stenting to the qualifying events. The perioperative stroke rate was significantly higher in patients treated within 21 days after the qualifying events, compared to those beyond 21 days (IRR = 1.60, 95%CI: 1.10-2.33; p = 0.014), similar relationships were obtained for both post-procedural (IRR = 1.61, 95%CI: 1.02-2.55; p = 0.042) and 1-year (IRR = 1.51, 95%CI: 1.10-2.08; p = 0.012) stroke or death rate. Conclusions: The timing of intracranial stenting may influence the safety and efficacy outcomes of stenting. Intracranial stenting within 21 days from the qualifying events may confer a higher risk of stroke or death. More studies are needed to confirm the impact of timing and the proper cut-off value.

Pocket-Size Mobile Echocardiographic Screening of Thoracic Aortic Aneurysms in Hypertensive Patients.

BACKGROUND: Patients with hypertension may develop a thoracic aortic aneurysm (TAA) that can be asymptomatic but potentially life-threatening. We sought to assess the prevalence of asymptomatic TAA among hypertensive patients with a point-of-care screening program using pocket-size mobile echocardiographic (PME) devices. METHODS: We prospectively performed transthoracic aortic ultrasound using a PME device on patients attending our hypertension clinics between June 2016 and July 2018. The echo examinations were performed by a research fellow to obtain aortic diameter measurements including the aortic sinus, sinotubular junction, ascending aorta, aortic arch, and descending thoracic aorta through various standard echo views. Images were stored on the PME and transferred to a desktop computer for measurements and further statistical analysis. RESULTS: During the study period 1529 hypertensive patients (mean age, 62 years [range, 30-85]; 824 men) were recruited. The prevalence of TAA (defined as maximum aortic diameter ≥ 4.5 cm and/or >50% larger than the diameter of the adjacent normal aorta) in our study population was 7.5% (115/1529). Multiple logistic regression analysis identified male gender (odds ratio, 2.120; P < .001) and older age (odds ratio, 1.031; P < .001) as independent factors associated with TAA. CONCLUSIONS: Silent TAA is common among hypertensive patients in Hong Kong. We found the PME device to be effective in detecting TAA in a clinic setting. Such an approach may be useful for early detection of TAA among at-risk patients, allowing aggressive blood pressure control and early surgical intervention to prevent catastrophic complications.

Inadvertent arterial & venous injury by bone marrow biopsy needle: case report on rescue embolization techniques.

BACKGROUND: Bone marrow biopsy is a common medical procedure for diagnosis and characterization of haematological diseases. It is generally regarded as a safe procedure with low rate of major complications. Inadvertent vascular injury is however an uncommon but important complication of bone marrow biopsy procedure. The knowledge of a safe and effective embolization method is crucial for interventional radiologists to reduce significant patient morbidity and mortality, shall such inadvertent vascular injury occurs. CASE PRESENTATION: Bedside bone marrow biopsy was performed for an elderly gentleman to evaluate for his underlying acute leukaemia. Biopsy needle inadvertently injured the internal iliac artery and vein during the procedure. Coil embolization was carefully performed across injured arterial segment via the culprit biopsy needle until contrast cessation. Concomitant venous injury was subsequently confirmed on angiography when the needle was withdrawn for a short distance from the iliac artery. This venous injury was tackled by further withdrawing the biopsy needle to distal end of the bone marrow tract for tract embolization with coils and gelatin sponges. High caution was made to avoid coil dislodgement into the iliac vein, to prevent pulmonary embolism. Patient was clinically stable throughout the procedure. Post-procedure contrast CT shows no pelvic haematoma or contrast extravasation. CONCLUSIONS: This case illustrates rescue embolization techniques for rare life-threatening concomitant internal iliac arterial and venous injuries by a bone marrow biopsy needle. Interventional radiologists can play an important role in carrying out precise embolization to avoid significant patient morbidity and mortality in the case of life-threatening haemorrhage.

Transarterial Ethanol Ablation for Small Hepatocellular Carcinoma (≤ 3 cm): A Comparative Study Versus Radiofrequency Ablation.

PURPOSE: The objective was to evaluate the local treatment efficacy of transarterial ethanol ablation (TEA) as compared to radiofrequency ablation (RFA) for small hepatocellular carcinoma (HCC). MATERIALS AND METHODS: This was a retrospective study between January 2005 and April 2017, in which the treatment outcomes of all patients who received either percutaneous TEA or RFA for HCC tumors of size ≤ 3 cm, of Child-Pugh grade A or B, received no prior treatment other than surgical resection, were compared. For TEA, a mixture of absolute ethanol and ethiodized oil at a proportion of 1:2 by volume was administered superselectively into the tumor via a microcatheter placed at the feeding arteries. The TEA group and the RFA group consisted of 68 consecutive patients (88 treated target tumors) and 129 consecutive patients (129 tumors), respectively. RESULTS: Technical success was achieved in all the target tumors in both groups. Grade 3 complication (CIRSE Classification) of prolonged fever occurred in 3 cases with multi-focal and large tumors in the TEA group. There was no statistically significant difference in complete response rate between the TEA group (84/88 or 95.5%) and the RFA group (188/195 or 96.4%) (p = 0.7). Time to progression in the TEA group [median 11.9 months, interquartile range (IQR) 5.6-18 months] was not statistically different from that in the RFA group (median 9.5 months, IQR 3.5-18.7 months) (p = 0.773). CONCLUSION: TEA could be an effective alternative of RFA for the local treatment of small HCC; it is especially valuable for tumors of unfavorable location.