[Transarterial radioembolization of hepatocellular carcinoma and intrahepatic cholangiocarcinoma]. / Transarterielle Radioembolisation des hepatozellulären Karzinoms und des intrahepatischen Cholangiokarzinoms.

Since the first version of the S3 guideline for the diagnosis and treatment of hepatocellular carcinoma (HCC) in 2013, a large number of studies have consolidated the data on transarterial radioembolization (TARE) and created a broad evidence base. As a result, TARE was incorporated into the current 2021 S3 guideline with a number of specific recommendations, whereas it was previously only offered under study conditions. TARE is now offered with the other minimally invasive procedures for bridging and downstaging before liver transplantation, but also as an alternative to transarterial chemotherapy (TACE) in intermediate HCC and in locally limited intrahepatic cholangiocarcinoma in second-line therapy for selected patients-albeit with different levels of evidence. Based on the study situation, however, TARE is not recommended for advanced HCC; here, systemic therapy with immunotherapeutic agents is preferred based on current data.

[International comparison of radiological aspects of the new German S3 guideline on hepatocellular carcinoma and intrahepatic cholangiocarcinoma]. / Radiologische Aspekte der neuen deutschen S3-Leitlinie zum hepatozellulären Karzinom und biliären Karzinomen im internationalen Vergleich.

The updated German S3 guideline "Diagnostics and therapy of hepatocellular carcinoma and biliary carcinomas" covers two tumor entities. The original guideline published in 2013 focusing only on the diagnosis and therapy of hepatocellular carcinoma (HCC) has been expanded to include intrahepatic cholangiocarcinoma. These guidelines were developed within the framework of the guideline program on oncology of the Scientific Medical Society e. V. (AWMF), the German Cancer Society (DKG) and German Cancer Aid Society (DKG) under the auspices of the German Society for Digestive and Metabolic Diseases (DGVS). In addition to updated recommendations regarding histopathology, radiological diagnostics and treatments, the main innovations of the revised guidelines on HCC include a complete revision of the section on the systemic therapeutic approach in advanced stages of the disease. This article presents the significance of the current recommendations for diagnostic and interventional radiology in comparison to other national and international guidelines and should serve to improve the quality of patient care through more widespread dissemination.

Consensus Guidelines for the Definition of Time-to-Event End Points in Image-guided Tumor Ablation: Results of the SIO and DATECAN Initiative.

There is currently no consensus regarding preferred clinical outcome measures following image-guided tumor ablation or clear definitions of oncologic end points. This consensus document proposes standardized definitions for a broad range of oncologic outcome measures with recommendations on how to uniformly document, analyze, and report outcomes. The initiative was coordinated by the Society of Interventional Oncology in collaboration with the Definition for the Assessment of Time-to-Event End Points in Cancer Trials, or DATECAN, group. According to predefined criteria, based on experience with clinical trials, an international panel of 62 experts convened. Recommendations were developed using the validated three-step modified Delphi consensus method. Consensus was reached on when to assess outcomes per patient, per session, or per tumor; on starting and ending time and survival time definitions; and on time-to-event end points. Although no consensus was reached on the preferred classification system to report complications, quality of life, and health economics issues, the panel did agree on using the most recent version of a validated patient-reported outcome questionnaire. This article provides a framework of key opinion leader recommendations with the intent to facilitate a clear interpretation of results and standardize worldwide communication. Widespread adoption will improve reproducibility, allow for accurate comparisons, and avoid misinterpretations in the field of interventional oncology research. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Liddell in this issue.

Intra-arterial Injection of Lidocaine as a Cell Sensitizer during Irreversible Electroporation.

PURPOSE: To investigate whether intra-arterial injection of lidocaine enhances irreversible electroporation (IRE) in a liver model. MATERIALS AND METHODS: Conventional IRE (C-IRE) and lidocaine-enhanced IRE (L-IRE) were performed in 8 pig livers. Protocol 1 (tip exposure and electrode distance of 2.0 cm each) and protocol 2 (increased tip exposure and electrode distance 2.5 cm each) were used. Animals were sacrificed 3 hours after IRE. Study goals included electrical tissue properties (eg, current, conductivity) during IRE, geometry of IRE zones analyzed using computed tomography and magnetic resonance imaging (eg, volume and sphericity index), degree of acute liver damage, and irreversible cell death analyzed using microscopy (hematoxylin and eosin staining and terminal deoxynucleotidyl transferase deoxyuridine 5-triphosphate nick end labeling). Statistical comparisons were performed using the paired t test and Wilcoxon test. RESULTS: All treatments were performed without adverse events. Electrical tissue properties were not significantly different between C-IRE and L-IRE. For protocol 1, the diameter of the largest sphere within the IRE zone was significantly larger for L-IRE than for C-IRE (25.0 ± 4.7 mm vs 18.4 ± 3.1 mm [P = .013]). For protocol 2, the volume of IRE zone was significantly larger for L-IRE compared with C-IRE (46.0 ± 5.4 cm3 vs 22.6 ± 6.4 cm3 [P = .018]), as well as the diameter of the largest sphere within the IRE zone (27.1 ± 2.2 mm vs 19.8 ± 2.3 mm [P = .020]). For protocol 1, a significantly higher degree of irreversible cell death was noted for L-IRE than for C-IRE (1.8 ± 1.0 vs 0.8 ± 1.0 [P = .046]). CONCLUSIONS: Intra-arterial injection of lidocaine can enhance IRE in terms of larger IRE zones and an increase of irreversible cell death.

Feasibility, efficacy, and safety of percutaneous MR-guided ablation of small (≤12 mm) hepatic malignancies.

BACKGROUND: Percutaneous tumor ablation is commonly performed using computed tomography (CT) or ultrasound (US) guidance, although reliable visualization of the target tumor may be challenging. MRI guidance provides more reliable visualization of target tumors and allows for real-time imaging and multiplanar capabilities, making it the modality of choice, in particular if lesions are small. PURPOSE: To investigate the feasibility, technical success, and safety of percutaneous MR-guided ablation (RFA n = 27 / MWA n = 16) of small (≤12 mm) hepatic malignancies. STUDY TYPE: Retrospective case study. POPULATION: In all, 45 patients (age: 61.1 ± 11.8) with hepatic malignancies and a lesion diameter of ≤12 mm scheduled for percutaneous MR-guided tumor ablation based on a tumor board decision were included. FIELD STRENGTH: A 1.5T MR system was used for planning, targeting, and monitoring. ASSESSMENT: Feasibility assessment included the detection of the target tumor, tumor delineation during MR-fluoroscopy guided targeting, and the number of attempts needed for precise applicator placement. Technical success was defined as successful performance of the procedure including a safety margin of 5 mm. Safety evaluation was based on procedure-related complications. STATISTICAL TEST: Frequency. RESULTS: Tumor ablation (mean diameter 9.0 ± 2.1 mm) was successfully completed in 43/45 patients. Planning imaging was conducted without a contrast agent in 79% (n = 37). In 64% (n = 30), the target tumors were visible with MR-fluoroscopy. In six patients (13%), planning imaging revealed new, unexpected small lesions, which were either treated in the same session (n = 4) or changed therapy management (n = 2) due to diffuse tumor progress. Postprocedural imaging revealed a technical success of 100% (43/43), with no major complications. During follow-up, no local tumor progression was observed (mean follow-up 24.7 ± 14.0 months) although 28% (12) patients developed new hepatic lesions distant to the ablation zone. No major complications were observed. DATA CONCLUSION: MR-guided ablation is a feasible approach for an effective and safe treatment of small hepatic malignancies. LEVEL OF EVIDENCE: 4 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2019;49:374-381.

The value of iterative metal artifact reduction algorithms during antenna positioning for CT-guided microwave ablation.

Objectives: To compare image quality between filtered back projection (FBP) and iterative reconstruction algorithm and dedicated metal artifact reduction (iMAR) algorithms during antenna positioning for computed tomography-guided microwave ablation (MWA).Materials and methods: An MWA antenna was positioned in the liver of five pigs under CT guidance. Different exposure settings (120kVp/200mAs-120kVp/50mAs) and image reconstruction techniques (FBP, iterative reconstruction with and without iMAR) were applied. Quantitative image analysis included density measurements in six positions (e.g., liver in extension of the antenna [ANTENNA] and liver >3 cm away from the antenna [LIVER-1]). Qualitative image analysis included assessment of overall quality, image noise, artifacts at the antenna tip, artifacts in liver parenchyma bordering antenna tip and newly generated artifacts. Two independent observers performed the analyses twice and interreader agreement was compared with Bland-Altman analysis.Results: For all exposure and reconstruction settings, density measurements for ANTENNA were significantly higher for the I30-1 iMAR compared with FBP and I30-1 (e.g., 8.3-17.2HU vs. -104.5 to 155.1HU; p ≤ 0.01, respectively). In contrast, for all exposure settings, density measurements for LIVER-1 were comparable between FBP and I30-1 iMAR (e.g., 49.4-50.4HU vs. 50.1-52.5U, respectively). For all exposure and reconstruction settings, subjective image quality for LIVER-1 was better for the I30-1 iMAR algorithm compared with FBP and I30-1. Bland-Altman interobserver agreement was from -0.2 to 0.2 for FBP and iMAR, and Cohen's kappa was 0.74.Conclusion: Iterative algorithms I30-1 with iMAR algorithm improves image quality during antenna positioning and placement for CT-guided MWA and is applicable over a range of exposure settings.

Intraprocedural 3D perfusion measurement during chemoembolisation with doxorubicin-eluting beads in liver metastases of malignant melanoma.

OBJECTIVES: To study feasibility and validity of a new software application for intraprocedural assessment of perfusion during chemoembolisation of melanoma metastases. METHODOLOGY: In a prospective phase-II trial, ten melanoma patients with liver-only metastases underwent chemoembolisation with doxorubicin-eluting beads (DEBDOX-TACE). Tumour perfusion was evaluated immediately before and after treatment at cone beam computer tomography (CBCT) using a new software application. For control and comparison, patients underwent perfusion measurement via contrast-enhanced multidetector CT (MDCT) before and after treatment. RESULTS: CBCT showed 94.7 % reduction in perfusion in metastases after DEBDOX-TACE, whereas MDCT showed 96.8 %. Reduction in perfusion after treatment was statistically significant (p < 0.01) for both methods. The additional time needed for data acquisition during treatment was 5 min per case or less; the post-processing data analysis was 10 min or less. Perfusion imaging was associated with additional contrast agent and patient exposure to radiation (dose-length product [DLP]): 18 ml and 394 mGy*cm in CBCT and 100 ml and 446 mGy*cm in MDCT, respectively. CONCLUSIONS: Reduction in perfusion of melanoma metastases after DEBDOX-TACE can be reliably assessed during the intervention via perfusion software at CBCT. Data acquisition and analysis require additional time but can be easily performed during the treatment. KEY POINTS: • Tumour perfusion of melanoma metastases can be assessed at cone beam CT. • The software shows a significant decrease of tumour perfusion after DEBDOX-TACE. • Data acquisition and analysis require an acceptable additional time during the procedure. • CBCT requires less radiation exposure and contrast for perfusion study than MSCT. • This software can monitor the course of DEBDOX-TACE in melanoma metastases.

In vitro artifact assessment of an MR-compatible, microwave antenna device for percutaneous tumor ablation with fluoroscopic MRI-sequences.

OBJECTIVE: To evaluate artifact configuration and diameters of a magnetic resonance (MR) compatible microwave (MW) applicator using near-realtime MR-fluoroscopic sequences for percutaneous tumor ablation procedures. MATERIAL AND METHODS: Two MW applicators (14 G and 16 G) were tested in an ex-vivo phantom at 1.5 T with two 3 D fluoroscopic sequences: T1-weighted spoiled Gradient Echo (GRE) and T1/T2-weighted Steady State Free Precession (SSFP) sequence. Applicator orientation to main magnetic field (B0), slice orientation and phase encoding direction (PED) were systematically varied. The influence of these variables was assessed with ANOVA and post-hoc testing. RESULTS: The artifact was homogenous along the whole length of both antennas with all tested parameters. The tip artifact diameter of the 16 G antenna measured 6.9 ± 1.0 mm, the shaft artifact diameter 8.6 ± 1.2 mm and the Tip Location Error (TLE) was 1.5 ± 1.2 mm.The tip artifact diameter of the 14 G antenna measured 7.7 ± 1.2 mm, the shaft artifact diameter 9.6 ± 1.5 mm and TLE was 1.6 ± 1.2 mm. Orientation to B0 had no statistically significant influence on tip artifact diameters (16 G: p = .55; 14 G: p = .07) or TLE (16 G: p = .93; 14 G: p = .26). GRE sequences slightly overestimated the antenna length with TLE(16 G) = 2.6 ± 0.5 mm and TLE(14 G) = 2.7 ± 0.7 mm. CONCLUSIONS: The MR-compatible MW applicator's artifact seems adequate with an acceptable TLE for safe applicator positioning during near-realtime fluoroscopic MR-guidance.

MR-guided microwave ablation in hepatic tumours: initial results in clinical routine.

OBJECTIVES: Evaluation of the technical success, patient safety and technical effectiveness of magnetic resonance (MR)-guided microwave ablation of hepatic malignancies. METHODS: Institutional review board approval and informed patient consent were obtained. Fifteen patients (59.8 years ± 9.5) with 18 hepatic malignancies (7 hepatocellular carcinomas, 11 metastases) underwent MR-guided microwave ablation using a 1.5-T MR system. Mean tumour size was 15.4 mm ± 7.7 (7-37 mm). Technical success and ablation zone diameters were assessed by post-ablative MR imaging. Technique effectiveness was assessed after 1 month. Complications were classified according to the Common Terminology Criteria for Adverse Events (CTCAE). Mean follow-up was 5.8 months ± 2.6 (1-10 months). RESULTS: Technical success and technique effectiveness were achieved in all lesions. Lesions were treated using 2.5 ± 1.2 applicator positions. Mean energy and ablation duration per tumour were 37.6 kJ ± 21.7 (9-87 kJ) and 24.7 min ± 11.1 (7-49 min), respectively. Coagulation zone short- and long-axis diameters were 31.5 mm ± 10.5 (16-65 mm) and 52.7 mm ± 15.4 (27-94 mm), respectively. Two CTCAE-2-complications occurred (pneumothorax, pleural effusion). Seven patients developed new tumour manifestations in the untreated liver. Local tumour progression was not observed. CONCLUSIONS: Microwave ablation is feasible under near real-time MR guidance and provides effective treatment of hepatic malignancies in one session. KEY POINTS: • Planning, applicator placement and therapy monitoring are possible without using contrast enhancement • Energy transmission from the generator to the scanner room is safely possible • MR-guided microwave ablation provides effective treatment of hepatic malignancies in one session • Therapy monitoring is possible without applicator retraction from the ablation site.

Preclinical evaluation of an MR-compatible microwave ablation system and comparison with a standard microwave ablation system in an ex vivo bovine liver model.

OBJECTIVE: Evaluation of a newly developed MR-compatible microwave ablation system with focus on ablation performance and comparison with a corresponding standard microwave ablation system. MATERIALS AND METHODS: A total of 52 ablations were performed with a non-cooled microwave ablation system in an ex vivo bovine liver model using the following settings: [A] 16G-standard antenna, 2 cm active tip, 2.4 m cable; [B] MR-compatible 16G-antenna, 2 cm active tip, 2.4 m cable; [C] MR-compatible 16G-antenna, 2 cm active tip, extended 6 m cable; and [D] MR-compatible 16G-antenna, 4 cm active tip, extended 6 m cable. Ablation durations were 3, 5 and 10 min, and additionally 15 min for [D]. Ablations zones were measured for short-axis diameter (SA) and long-axis diameter (LA). Settings [A]-[C] were compared regarding SA, volume (V) and generator energy output (E) with analysis of variance and Tukey-Kramer post hoc test. Ablation performance of the MR-compatible settings [C] and [D] were compared regarding SA, V, E and sphericity index (SA/LA) with unpaired t-test. p < 0.05 was considered as statistically significant. RESULTS: No significant differences were found between [A], [B] and [C] regarding SA and V (10 min; SA[A] = 25.8 ± 2.4 mm, SA[B] = 25.3 ± 1.9 mm, SA[C] = 25.0 ± 2.0 mm, p = 0.88; V[A] = 17.8 ± 4.4 cm³, V[B] = 16.6 ± 3.0 cm³, V[C] = 17.8 ± 2.7 cm³, p = 0.85); however, the highest energy output was measured for setting [C] (10 min; [A]: 9.9 ± 0.5 kJ, [B]: 10.1 ± 0.5 kJ, [C]: 13.1 ± 0.3 kJ, p < 0.001). SA, V and E were significantly larger with setting [D] than [C] with 10 min ablations (SA[C] = 25.0 ± 2.0 mm, SA[D] = 34.0 ± 2.9 mm, p = 0.003; V[C] = 17.8 ± 2.7 cm³, V[D] = 39.4 ± 7.5 cm³, p = 0.007; E[C] = 13.1 ± 0.3 kJ, E[D] = 16.7 ± 0.8 kJ, p = 0.002) without significant difference in sphericity index (SA/LA[C] = 0.46 ± 0.02, SA/LA[D] = 0.52 ± 0.04, p = 0.08). CONCLUSION: The tested MR-compatible system can be used without loss of ablation performance compared to the standard system.

Degradable Starch Microspheres Transcatheter Arterial Chemoembolization (DSM-TACE) in Intrahepatic Cholangiocellular Carcinoma (ICC): Results from a National Multi-Center Study on Safety and Efficacy.

BACKGROUND The aim of this study was to evaluate the safety and efficacy of DSM (degradable starch microspheres) as an embolic agent in transarterial chemoembolization in the treatment of intrahepatic cholangiocellular carcinoma (ICC). MATERIAL AND METHODS This was a national, multi-center observational cohort study on the safety and efficacy of DSM-TACE using mitomycin, gemcitabine, cisplatin, doxorubicin, and carboplatin in palliative treatment of ICC. Recruitment period for the study was from January 2010 to June 2014. Primary endpoints were toxicity, safety, and response according to mRECIST criteria. RESULTS Twenty-five DSM-TACE procedures in cases of advanced ICC were performed in seven patients. Nausea and vomiting occurred as adverse event (AE) in eight out of 25 treatments (32%), with seven of eight events (87.5%) associated with the use of gemcitabine. In 11 out of 25 treatments (44%) moderate, transient epigastric pain was registered as an adverse event (AE) within 24 hours of DSM-TACE. One case (1/25) of severe AE (4%) with thrombocytopenia led to discontinuation of the DSM-TACE-treatment. A total of 25 DSM-TACE procedures with complete clinical and imaging follow-up over a two-year-period were analyzed: objective response (OR) was achieved in three of 25 treatments (12%) Disease control (DC) was achieved in 44% (11/25) of treatments; progress was registered in 4% (1/25). CONCLUSIONS The use of DSM as an embolic agent for TACE is safe in the treatment of ICC. A standardized anti-emetic medication should be established, especially when using gemcitabine. Further prospective studies need to be conducted to find the most suitable, standardized DSM-TACE treatment regime.

An in-vitro evaluation of three types of drug-eluting microspheres loaded with irinotecan.

To compare the mechanical and chemical properties of three commercially available microspheres loaded with irinotecan. LifePearl (200 µm), DC Bead (100-300 µm), and Tandem (100 µm) microspheres were loaded with irinotecan. For loading, elution, and stability determinations, irinotecan concentrations were quantified using validated high-performance liquid chromatography methods. In-vitro elution was performed over 24 h using a USP 4 dissolution apparatus. Diameter measurements were performed using light microscopy. Time in suspension was considered as the time required for the microspheres to vacate 1/3 of the volume. All three microsphere types rapidly loaded irinotecan, with more than 95% loading at 1 h. In-vitro elution of irinotecan was rapid for LifePearl and DC Bead microspheres, with more than 98% elution at 1 h, and delayed for Tandem microspheres, with about 70% elution at 6 h. After loading with irinotecan, the average diameter of LifePearl and DC Bead microspheres was reduced by 9 and 18%, respectively, and was unchanged for Tandem microspheres. All three microsphere types lost 4-6% of the loaded irinotecan almost immediately upon placement in contrast: water and contrast: 5% dextrose, but further losses were minimal over 2 weeks. LifePearl microspheres remained longer in suspension (392±23 s) compared with DC Bead (154±13 s, P<0.001) and Tandem (198±19 s, P<0.001) microspheres. All three microsphere types load irinotecan rapidly. LifePearl and DC Bead microspheres elute irinotecan rapidly. Elution is delayed with Tandem microspheres. LifePearl microspheres show the longest time in suspension.

In vitro artefact assessment of a new MR-compatible microwave antenna and a standard MR-compatible radiofrequency ablation electrode for tumour ablation.

OBJECTIVE: To evaluate and compare artefact configuration and diameters in a magnetic resonance (MR)-compatible prototype microwave (MW) applicator and a standard MR-compatible radiofrequency (RF) applicator for MR-guided tumour ablation. METHODS: Both applicators were tested in a phantom study at 1.5T with three sequences: T1-weighted three-dimensional volume interpolated breath-hold examination (VIBE), T1-weighted fast low angle shot (FLASH), T2-weighted turbo spin echo (TSE). Applicator orientation to main magnetic field (B0) and slice orientation were varied. Needle tip location error (TLE) was assessed, and artefact diameters were calculated. Influence of imaging parameters on artefacts was assessed with analysis of variance (ANOVA) and post hoc testing. RESULTS: MW applicator: the shaft artefact diameter measured 2.3 +/- 0.8 mm. Tip artefact diameter and length measured 2.2 ± 0.8 mm and 2.4 ± 1.3 mm, respectively. A prominent oval artefact (diameter: 16.5 +/- 1.8 mm, length: 19.1 +/- 2.5 mm) appeared close to the tip. TLE: - .3 +/- 0.6 mm. RF applicator: shaft and tip diameter measured 8.9 +/- 4.7 mm and 9.0 +/- .0 mm, respectively. TLE: -0.1 +/- 0.8 mm. Minimal artefacts were measured with RF applicator orientation parallel to B0 (P < 0.0001), whereas no such influence was found for MW applicator. For both applicators, significantly large artefacts were measured with T1 FLASH (P = 0.03). CONCLUSION: The MW applicator's artefact is satisfactory and seems useable for MR-guided ablation procedures. KEY POINTS: MW applicator's artefact appearance is independent of angulation to main magnetic field. MW applicator's prominent distal artefact may increase visibility under MR-guidance. RF and MW applicator's artefacts are precise concerning tip depiction. Largest artefact diameters are measured with T1-weighted fast low angle shot sequence.

Electrochemical Effects after Transarterial Chemoembolization in Combination with Percutaneous Irreversible Electroporation: Observations in an Acute Porcine Liver Model.

PURPOSE: To evaluate the effects of combined use of transarterial chemoembolization and irreversible electroporation (IRE) for focal tissue ablation in an acute porcine liver model. MATERIALS AND METHODS: Two established interventional techniques were combined: IRE with zones of irreversible and reversible electroporation and chemoembolization with microspheres, iodized oil, and doxorubicin. IRE was performed before chemoembolization in two pigs (pigs 1 and 2; IRE/chemoembolization group), chemoembolization was performed before IRE in two pigs (pigs 3 and 4; chemoembolization/IRE group), and only IRE was performed in two pigs (pigs 5 and 6). Five study groups were defined: IRE/chemoembolization (pigs 1 and 2), chemoembolization/IRE (pigs 3 and 4), IRE only (pigs 5 and 6), chemoembolization only (tissue outside the IRE zones in pigs 1-4), and control (untreated liver tissue outside the IRE zones in pigs 5 and 6). Animals were euthanized 2 hours after intervention. Size and shape of IRE zones on contrast-enhanced computed tomography, cell death on light microscopy, and doxorubicin tissue concentrations on chromatography and fluorescence microscopy were analyzed. RESULTS: Size and shape of IRE zones were not significantly different (eg, P = .067 for volume). A histologic marker for irreversible cell death was positive in IRE/chemoembolization, chemoembolization/IRE, and IRE groups only in the macroscopically visible IRE zones. Doxorubicin tissue concentrations were not significantly different (P = .873). However, in the reversible electroporation (RE) zones, broad areas with intense intranuclear doxorubicin accumulation were observed in IRE/chemoembolization but not in chemoembolization/IRE and chemoembolization groups. CONCLUSIONS: IRE before chemoembolization enhances the intranuclear accumulation of doxorubicin in the RE zone.

Transarterial chemoembolization (TACE) for colorectal liver metastases--current status and critical review.

BACKGROUND: Transarterial liver-directed therapies are currently not recommended as a standard treatment for colorectal liver metastases. Transarterial chemoembolization (TACE), however, is increasingly used for patients with liver-dominant colorectal metastases after failure of surgery or systemic chemotherapy. The limited available data potentially reveals TACE as a valuable option for pre- and post-operative downsizing, minimizing time-to-surgery, and prolongation of overall survival after surgery in patients with colorectal liver only metastases. PURPOSE: In this overview, the current status of TACE for the treatment of liver-dominant colorectal liver metastases is presented. Critical comments on its rationale, technical success, complications, toxicity, and side effects as well as oncologic outcomes are discussed. The role of TACE as a valuable adjunct to surgery is addressed regarding pre- and post-operative downsizing, conversion to resectability as well as improvement of the recurrence rate after potentially curative liver resection. Additionally, the concept of TACE for liver-dominant metastatic disease with a focus on new embolization technologies is outlined. CONCLUSIONS: There is encouraging data with regard to technical success, safety, and oncologic efficacy of TACE for colorectal liver metastases. The majority of studies are non-randomized single-center series mostly after failure of systemic therapies in the 2nd line and beyond. Emerging techniques including embolization with calibrated microspheres, with or without additional cytotoxic drugs, degradable starch microspheres, and technical innovations, e.g., cone-beam computed tomography (CT) allow a new highly standardized TACE procedure. The real efficacy of TACE for colorectal liver metastases in a neoadjuvant, adjuvant, and palliative setting has now to be evaluated in prospective randomized controlled trials.

Diffusion-weighted imaging during MR-guided radiofrequency ablation of hepatic malignancies: analysis of immediate pre- and post-ablative diffusion characteristics.

BACKGROUND: Previous studies have shown a benefit of magnetic resonance (MR)-diffusion-weighted imaging (DWI) for follow-up after liver radiofrequency (RF) ablation. However, no data are available concerning acute changes of DWI characteristics immediately after RF ablation. PURPOSE: To analyze and compare the MR-diffusion characteristics of pre-interventional hepatic malignancies and the ablation zone during successful MR-guided RF ablation. MATERIAL AND METHODS: This retrospective study was conducted in accordance with the guidelines of the local institutional review board. Forty-seven patients with 29 HCC (24 patients) and 30 hepatic metastases (23 patients) underwent MR-guided radiofrequency ablation including DWI before and immediately after ablation (b = 0, 400, 800 s/mm(2)). Two reviewers (A and B) analyzed DWI with focus on detectability of the tumor before ablation and characteristics of the coagulative area after treatment. Mean apparent diffusion coefficient (ADC) was compared between liver, untreated tumor, and hyperintense areas in post-ablative DWI (b = 800 s/mm(2)) with the paired Student's t-test. RESULTS: Pre-ablative: the reviewers classified 19/29 (A) and 23/29 (B) HCC and 25/30 (A and B) metastases as detectable in DWI. Post-ablative: a hyperintense rim surrounding the ablation zone was observed in 28/29 treated HCC and 30/30 treated metastases (A and B). A homogenous hypointense central ablation zone was found in 18/29 (A) and 20/29 (B) treated HCC and 17/30 (A & B) treated metastases in DWI. ADC of the rim was significantly lower than ADC of the liver (P < 0.001). CONCLUSION: DWI enables visualization of the target tumor in MR-guided liver radiofrequency ablation in most cases. A common post-ablative DWI finding is a hyperintense rim with decreased ADC surrounding the ablation zone.

Image-guided tumor ablation: standardization of terminology and reporting criteria--a 10-year update.

Image-guided tumor ablation has become a well-established hallmark of local cancer therapy. The breadth of options available in this growing field increases the need for standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison among treatments that use different technologies, such as chemical (eg, ethanol or acetic acid) ablation, thermal therapies (eg, radiofrequency, laser, microwave, focused ultrasound, and cryoablation) and newer ablative modalities such as irreversible electroporation. This updated consensus document provides a framework that will facilitate the clearest communication among investigators regarding ablative technologies. An appropriate vehicle is proposed for reporting the various aspects of image-guided ablation therapy including classification of therapies, procedure terms, descriptors of imaging guidance, and terminology for imaging and pathologic findings. Methods are addressed for standardizing reporting of technique, follow-up, complications, and clinical results. As noted in the original document from 2003, adherence to the recommendations will improve the precision of communications in this field, leading to more accurate comparison of technologies and results, and ultimately to improved patient outcomes. Online supplemental material is available for this article .

Image-guided tumor ablation: standardization of terminology and reporting criteria--a 10-year update.

Image-guided tumor ablation has become a well-established hallmark of local cancer therapy. The breadth of options available in this growing field increases the need for standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison among treatments that use different technologies, such as chemical (eg, ethanol or acetic acid) ablation, thermal therapies (eg, radiofrequency, laser, microwave, focused ultrasound, and cryoablation) and newer ablative modalities such as irreversible electroporation. This updated consensus document provides a framework that will facilitate the clearest communication among investigators regarding ablative technologies. An appropriate vehicle is proposed for reporting the various aspects of image-guided ablation therapy including classification of therapies, procedure terms, descriptors of imaging guidance, and terminology for imaging and pathologic findings. Methods are addressed for standardizing reporting of technique, follow-up, complications, and clinical results. As noted in the original document from 2003, adherence to the recommendations will improve the precision of communications in this field, leading to more accurate comparison of technologies and results, and ultimately to improved patient outcomes.

Specific CT 3D rendering of the treatment zone after Irreversible Electroporation (IRE) in a pig liver model: the "Chebyshev Center Concept" to define the maximum treatable tumor size.

BACKGROUND: Size and shape of the treatment zone after Irreversible electroporation (IRE) can be difficult to depict due to the use of multiple applicators with complex spatial configuration. Exact geometrical definition of the treatment zone, however, is mandatory for acute treatment control since incomplete tumor coverage results in limited oncological outcome. In this study, the "Chebyshev Center Concept" was introduced for CT 3d rendering to assess size and position of the maximum treatable tumor at a specific safety margin. METHODS: In seven pig livers, three different IRE protocols were applied to create treatment zones of different size and shape: Protocol 1 (n = 5 IREs), Protocol 2 (n = 5 IREs), and Protocol 3 (n = 5 IREs). Contrast-enhanced CT was used to assess the treatment zones. Technique A consisted of a semi-automated software prototype for CT 3d rendering with the "Chebyshev Center Concept" implemented (the "Chebyshev Center" is the center of the largest inscribed sphere within the treatment zone) with automated definition of parameters for size, shape and position. Technique B consisted of standard CT 3d analysis with manual definition of the same parameters but position. RESULTS: For Protocol 1 and 2, short diameter of the treatment zone and diameter of the largest inscribed sphere within the treatment zone were not significantly different between Technique A and B. For Protocol 3, short diameter of the treatment zone and diameter of the largest inscribed sphere within the treatment zone were significantly smaller for Technique A compared with Technique B (41.1 ± 13.1 mm versus 53.8 ± 1.1 mm and 39.0 ± 8.4 mm versus 53.8 ± 1.1 mm; p < 0.05 and p < 0.01). For Protocol 1, 2 and 3, sphericity of the treatment zone was significantly larger for Technique A compared with B. CONCLUSIONS: Regarding size and shape of the treatment zone after IRE, CT 3d rendering with the "Chebyshev Center Concept" implemented provides significantly different results compared with standard CT 3d analysis. Since the latter overestimates the size of the treatment zone, the "Chebyshev Center Concept" could be used for a more objective acute treatment control.