CT versus MR guidance for radiofrequency ablation in patients with colorectal liver metastases: a 10-year follow-up favors MR guidance.

Objectives: To compare the results of CT- vs MR-guided radiofrequency ablation (RFA) of liver metastases (LM) from colorectal cancer after 10 years of follow-up in an observational, retrospective, and multicentric study.

Methods: A total of 238 patients with 496 LM were treated with RFA either with CT (CT group) or magnetic resonance (MR group) guidance. Every ablated LM was assessed and followed up with diagnostic MRI.

Single-centre survival analysis over 10 years after MR-guided radiofrequency ablation of liver metastases from different tumour entities.

Background: Radiofrequency ablation (RFA) is a minimal-invasive, local therapy in patients with circumscribed metastatic disease. Although widely used, long time survival analysis of treated liver metastases is still pending while also analysing the patients' experience of MR-based radiofrequency.

Methods: Monocentric, retrospective analysis of long-time overall and progression free survival (OS; PFS) of 109 patients, treated with MRI-guided hepatic RFA between 1997 and 2010, focusing on colorectal cancer patients (CRC).

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.

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.

Diagnostic accuracy of different magnetic resonance imaging sequences for detecting local tumor progression after radiofrequency ablation of hepatic malignancies.

Objective: To evaluate the diagnostic accuracy of the individual sequences of a clinical routine liver MRI protocol for the detection of local tumour progression after radiofrequency (RF) ablation of hepatic malignancies.

Material And Methods: A cohort of 93 patients treated for 140 primary and secondary hepatic malignancies with RF ablation was assembled for this retrospective study. The cohort contained 31 cases of local tumour progression, which occurred 8.

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.

Comparison of Ga-labelled PSMA-11 and C-choline in the detection of prostate cancer metastases by PET/CT.

Purpose: Prostate-specific membrane antigen (PSMA) is expressed ubiquitously on the membrane of most prostate tumors and its metastasis. While PET/CT using C-choline was considered as the gold standard in the staging of prostate cancer, PET with radiolabelled PSMA ligands was introduced into the clinic in recent years. Our aim was to compare the PSMA ligand Ga-PSMA-11 with C-choline in patients with primary and recurrent prostate cancer.

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.

Imaging of HCC-Current State of the Art.

Early diagnosis of hepatocellular carcinoma (HCC) is crucial for optimizing treatment outcome. Ongoing advances are being made in imaging of HCC regarding detection, grading, staging, and also treatment monitoring. This review gives an overview of the current international guidelines for diagnosing HCC and their discrepancies as well as critically summarizes the role of magnetic resonance imaging (MRI) and computed tomography (CT) techniques for imaging in HCC.

Assessment of metastatic colorectal cancer with hybrid imaging: comparison of reading performance using different combinations of anatomical and functional imaging techniques in PET/MRI and PET/CT in a short case series.

Purpose: The purpose was to investigate the diagnostic performance of different combinations of anatomical and functional imaging techniques in PET/MRI and PET/CT for the evaluation of metastatic colorectal cancer lesions.

Methods: Image data of 15 colorectal cancer patients (FDG-PET/CT and subsequent FDG-PET/MRI) were retrospectively evaluated by two readers in five reading sessions: MRI (morphology) alone, MRI/diffusion-weighted MRI (DWI), MRI/PET, MRI/DWI/PET; and PET/CT. Diagnostic performance of lesion detection with each combination was assessed in general and organ-based.

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).

[Primary perivascular epitheloid cell tumour (PEComa) of the liver - is a new entity of the liver tumors?].

Perivascular epitheloid cell tumor (PEComa) is a rare tumor, characterized by dual Expression of smooth muscle and melanocytic markers. Due to the development of diagnostic procedures, we now diagnose PEComa more often. We report about a case of PEComa of the liver as an accidental finding.

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.

Transarterial chemoembolization using drug eluting beads and subsequent percutaneous MR-guided radiofrequency ablation in the therapy of intermediate sized hepatocellular carcinoma.

Objective: To evaluate safety, efficacy, survival and recurrence-free survival of transarterial chemoembolization (TACE) with drug eluting (DC) beads combined with MR-guided radiofrequency (RF) ablation for the treatment of hepatocellular carcinomas (HCC) larger than 3 cm.

Materials And Methods: This retrospective study was approved by the institutional review board. 20 patients (69.

A comparison of internally water-perfused and cryogenically cooled monopolar and bipolar radiofrequency applicators in ex vivo liver samples.

Rationale And Objectives: To evaluate the ex vivo ablation zones created in hepatic tissue using monopolar and bipolar gas- and water-cooled radiofrequency (RF) applicators.

Materials And Methods: RF ablations were performed on ex vivo bovine liver tissue using closed circuit water-cooled and closed circuit cryogenically cooled (via CO₂ enthalpy) 15-ga linear-needle applicators. Both monopolar and bipolar electrode applicators were used, with the electric current administered ranging in 50-mA increments from 1100 to 1300 mA for the monopolar case, and from 500 to 700 mA for the bipolar case.

Forms of energy delivery during cryo-cooled radiofrequency ablation for optimization of the ablation result.

Purpose: Energy transfer from radiofrequency (RF) applicator to tissue is both precondition and limiting factor. The purpose of this ex vivo study was to examine the influence of form of energy delivery on ablation result during RF ablation with cryo-cooled applicators.

Materials And Methods: One hundred eight ablations were performed in ex vivo bovine liver under continuous energy delivery (A), pulsed energy delivery with reduced current during ablation pause (B) and impedance-dependent energy delivery.

Liver lesion conspicuity during real-time MR-guided radiofrequency applicator placement using spoiled gradient echo and balanced steady-state free precession imaging.

Purpose: To retrospectively evaluate the conspicuity of liver lesions in a fluoroscopic spoiled gradient echo (GRE) and a balanced steady-state free precession (SSFP) magnetic resonance imaging (MRI) sequence.

Materials And Methods: In all, 103 patients with hepatocellular carcinomas (HCC) (41) or liver metastases (67) were treated using MR-guided radiofrequency ablation in a wide-bore 1.5 T scanner.

Encephalopathic Susac's Syndrome associated with livedo racemosa in a young woman before the completion of family planning.

Background: Susac's Syndrome (SS) consists of the triad of encephalopathy, branch retinal artery occlusions (BRAO) and hearing loss (HL). Histopathologically, SS is characterised by a microangiopathy, and some observations suggest that an immune-mediated damage of endothelial cells might play a role. These findings also implicate a similarity between SS and other autoimmune diseases, most notably juvenile dermatomyositis (JDM).

[Image-guided therapy with closed MRI: an update].

Standard Radiological Methods: Standard imaging modalities for percutaneous minimally invasive therapy are ultrasound, fluoroscopy and computed tomography.

Methodical Innovations: Magnetic resonance imaging is becoming increasingly more popular for minimally invasive procedures. The advantages are high soft-tissue contrast, the possibility of free selection of multiple imaging slices, multiple tools for intrainterventional monitoring and the absence of ionizing radiation for the patient and the interventional radiologist.

Image-guided radiofrequency ablation of hepatocellular carcinoma (HCC): is MR guidance more effective than CT guidance?

Objectives: The purpose of the study was to retrospectively compare technique effectiveness of computed tomography (CT)-guided versus magnetic resonance (MR)-guided radiofrequency (RF) ablation of hepatocellular carcinoma (HCC).

Materials And Methods: In 35 consecutive patients 53 CT-guided (n=29) or MR-guided (n=24) ablation procedures were performed in the treatment of 56 (CT: 29; MR: 27) HCC. The entire ablation procedure was performed at a multislice CT-scanner or an interventional 0.

Internally gas-cooled radiofrequency applicators as an alternative to conventional radiofrequency and microwave ablation devices: an in vivo comparison.

Purpose: To test the efficacy of internally CO2-cooled radiofrequency (RF) ablation in vivo and to compare its effectiveness to a standard water-cooled RF probe and to a gas-cooled microwave (MW) device.

Method And Materials: 49 ablations were performed on 15 pigs under general anesthesia using 15G monopolar CO2-cooled RF applicators, 17G monopolar water-cooled RF applicators and 15G internally CO2-cooled microwave devices. The power of the MW device was 45W, the current of the gas-cooled RF device was 1200-1600mA.

Therapy monitoring of magnetic resonance-guided radiofrequency ablation using T1- and T2-weighted sequences at 1.5 T: reliability of estimated ablation zones.

Purpose: The aim of this study was to compare the size and shape of the indicated ablation zone using magnetic resonance (MR) imaging with different contrast weightings after MR-guided radiofrequency ablation (RFA) at 1.5 T.

Materials And Methods: Magnetic resonance images of 50 patients treated for hepatic malignancies using MR-guided RFA were retrospectively evaluated.

Comparison of four microwave ablation devices: an experimental study in ex vivo bovine liver.

Purpose: To compare volume, sphericity, and short-axis diameter of the coagulation zone of four commercially available microwave ablation systems with three technical concepts in an ex vivo setting and to formulate mathematical models to predict these quantities.

Materials And Methods: Two high-power systems (systems A and B), a system that enables simultaneous use of three antennas (system C), and a non-perfusion-cooled system that automatically adapts power and frequency (system D) were tested in ex vivo bovine livers (108 ablations). Coagulation volume, sphericity, and mean short-axis diameter were assessed, and mathematical functions were fitted for each system and assessed with the coefficient of determination (R(2)).

MR-guided radiofrequency ablation using a wide-bore 1.5-T MR system: clinical results of 213 treated liver lesions.

Objective: To evaluate the technical effectiveness, technical success and patient safety of MR-guided radiofrequency (RF) ablation of liver malignancies using a wide-bore 1.5-T MR system.

Methods: In 110 patients, 56 primary liver lesions and 157 liver metastases were treated in 157 sessions using percutaneous RF ablation.

Prolonged antibiotic prophylaxis in patients with bilioenteric anastomosis undergoing percutaneous radiofrequency ablation.

Purpose: To reduce risk of development of a hepatic abscess in patients with preexisting bilioenteric anastomosis (BEA) undergoing radiofrequency (RF) ablation of hepatic tumors by use of prolonged antibiotic prophylaxis over at least 10 days.

Materials And Methods: Between April 2003 and June 2011, 184 patients underwent 206 percutaneous RF ablation procedures for hepatic malignancies. Eight patients presented with BEA and were treated in 10 sessions at 14 tumor locations.