Publications by authors named "Gregor Laimer"

Article Synopsis
  • Several new software methods have been developed to assess the minimum ablative margin during thermal ablation of colorectal liver metastases, aiming to enhance patient outcomes in a multi-institutional context.
  • This retrospective study analyzed 400 cases of thermal ablation over 13 years, focusing on minimum ablative margins and their correlation with local disease progression rates.
  • Results showed that a minimum ablative margin of 5 mm or more significantly reduces the risk of local tumor progression, confirming the importance of this margin across various institutions.
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Rationale And Objectives: To evaluate the targeting accuracy of a novel robot-assisted guidance technique relying on one pair of 2D C-arm images.

Material And Methods: In total, 160 punctures were carried out semi-automatically by using a novel robotic device. The needle's paths were planned based on one pair of 2D fluoroscopic images from different angles.

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Purpose: To assess the association between minimal ablative margin (MAM) and local tumor progression (LTP) following CT-guided thermal ablation of colorectal liver metastases (CRLM) in a multicenter cohort and across two confirmation software.

Materials And Methods: This multicenter retrospective study included patients who underwent CT-guided radiofrequency or microwave ablation for CRLM between 2009 and 2021 in three institutions. Three-dimensional (3D) MAM was retrospectively assessed using dedicated ablation confirmation software by automatic non-rigid (Ablation-fit) or semi-automatic rigid co-registration (SAFIR) of intraprocedural pre- and post-ablation contrast-enhanced CT scans by two independent reader teams blinded to patient outcomes.

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Objectives: The purpose of this study was to assess the performance of an optically tracked robot for computed-tomography (CT)-guided needle placements in a phantom study.

Methods: In total, 240 needle punctures were carried out with the help of an optically tracked robotic device (Micromate) based on CT image datasets at three different slice thicknesses (1, 3, and 5 mm). Conically shaped targets inside a gelatin-filled plexiglass phantom were punctured.

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Article Synopsis
  • Normothermic liver machine perfusion (NLMP) improves the preservation and assessment of liver organs, enhancing their utilization for transplantation, specifically in split liver transplantation (SLT).
  • A study analyzed outcomes from adult recipients who underwent SLT after NLMP, measuring 90-day graft and patient survival, as well as post-transplant complications.
  • Results showed that NLMP was safe and allowed successful delay of the second split liver graft transplantation, achieving a 100% survival rate at 90 days while documenting some early complications.
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Objectives: To compare the volumes and shapes of the coagulation zone (CZ) of a multi-probe RFA system (three RFA electrodes) and a single-probe MWA system from the same vendor in an ex vivo bovine liver model.

Material & Methods: A total of 48 CZs were obtained in bovine liver specimens with three different ablation system configurations (single-probe MWA vs. multi-probe RFA with 20 mm inter-probe distance [confluent CZ] vs.

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For both primary and metastatic liver cancer, thermal ablation represents an interesting alternative to surgery. However, except for a small fraction of patients, conventional ultrasound- and CT-guided single-probe approaches have not achieved oncologic outcomes comparable with surgery. In this overview, we describe our stereotactic ablation workflow and discuss the short- and long-term results of stereotactic radiofrequency ablation (SRFA) and stereotactic microwave ablation (SMWA) for the treatment of primary and secondary liver tumours.

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Rationale And Objectives: To evaluate the targeting accuracy of laser-guided punctures in combination with an aiming device for computed tomography (CT) interventions during in vitro experiments. MATERIALS AND METHODS: A total of 600 CT-guided punctures were performed using a laser target system, half of them with the additional help of an aiming device. Conically shaped targets in a plexiglass phantom were punctured.

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Purpose: To compare the results of a novice with those of experienced interventional radiologists (IRs) for stereotactic radiofrequency ablation (SRFA) of malignant liver tumors in terms of safety, technical success, and local tumor control.

Methods: A database, including all SRFA procedures performed in a single center between January 2011 and December 2018 was retrospectively analyzed. A total of 39 ablation sessions performed by a novice IR were compared to the results of three more experienced IRs.

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In the 2016 WHO classification of tumors of the central nervous system, hemangiopericytomas (HPCs) and solitary fibrous tumors (SFTs) were integrated into a new entity (SFT/HPC). Metastases to bone, liver, lung, and abdominal cavity are of concern. Only 37 cases of patients with liver metastases due to intracranial SFTs/HPCs have been reported.

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Arterial pseudoaneurysms (PSAs) typically occur after (iatrogenic) damage (i.e., puncture) to the arterial wall and are the most frequent complication following percutaneous interventions.

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Background: Robotic-based guidance systems are becoming increasingly capable of assisting in needle placement during interventional procedures. Despite these technical advances, less sophisticated low-cost guidance devices promise to enhance puncture accuracy compared with the traditional freehand technique. Purpose: To compare the in vitro accuracy and feasibility of two different aiming devices for computed-tomography (CT)-guided punctures.

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Objectives: To evaluate the targeting accuracy of stereotactic punctures based on a hybrid robotic device in combination with optical tracking-a phantom study.

Methods: CT data sets of a gelatin-filled plexiglass phantom with 1-, 3-, and 5-mm slice thickness were acquired. An optical navigation device served for planning of a total of 150 needle trajectories.

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Objectives: This study aimed to assess the safety and efficacy of stereotactic radiofrequency ablation (SRFA) in patients with hepatocellular adenomas (HCA).

Methods: Retrospective analyses of all patients referred for SRFA treatment at our institution between January 2010 and October 2020 revealed 14 patients (10 women; mean age 34.4 [range, 17-73 years]) with 38 HCAs treated through 18 ablation sessions.

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Purpose: To assess the technical outcome and local tumor control of multi-probe stereotactic radiofrequency ablation (SRFA) in a large series of patients. Furthermore, to determine factors accounting for adverse outcomes.

Material And Methods: Between 2003 and 2018, 865 patients were treated by SRFA for 2653 primary and metastatic liver tumors with a median tumor size of 2.

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Background: Radiofrequency ablation (RFA) is subject to "heat-sink" effects, particularly for treatment of tumors adjacent to major vessels.

Methods: In this retrospective study, 104 patients with 137 tumors (40 HCC, 10 ICC and 54 metastatic liver tumors) close to (≤1 cm from) the hepatic venous confluence underwent stereotactic RFA (SRFA) between June 2003 and June 2018. Median tumor size was 3.

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Aim: Torsion of the testicular appendages represents the most common cause of an acute scrotum in prepubertal boys. Its sonographic appearances on gray-scale US and color Doppler US have already been presented in several studies. The aim of this analysis was to expand those already established techniques with strain elastography and thus present typical features of this entity on multiparametric US.

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Thermal ablation is an emerging, potentially curative approach in treating primary and metastatic liver cancer. Different technologies are available, with radiofrequency ablation (RFA) and microwave ablation (MWA) being the most widely used. Regardless of the technique, destruction of the entire tumor, including an adequate safety margin, is key.

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Purpose: To evaluate safety, local oncological control, long-term outcome and potential prognostic factors of stereotactic RFA (SRFA) for the treatment of BCLMs.

Methods: Between July 2003 and December 2019, 42 consecutive female patients with median age 54.0 years were treated with SRFA at our institution for 110 BCLMs in 48 ablation sessions.

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Objectives: To retrospectively assess the periablational 3D safety margin in patients with colorectal liver metastases (CRLM) referred for stereotactic radiofrequency ablation (RFA) and to evaluate its influence on local treatment success.

Methods: Forty-five patients (31 males; mean age 64.5 [range 31-87 years]) with 76 CRLM were treated with stereotactic RFA and retrospectively analyzed.

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Objectives: To assess the difficulties in the immediate judgment of treatment success after radiofrequency ablation (RFA) of liver tumors by visual inspection alone and to evaluate whether radiologist's expertise affects the resultant judgment.

Methods: Peri-interventional CT-scans of nine patients with nine hepatocellular carcinomas with known outcomes after RFA were presented to 38 participants from 14 different countries. In a total of 342 reads, all interventional oncologists assessed the pre- and immediate post-interventional CT-scans through conventional side-by-side juxtapositioning of images and judged whether complete ablation (i.

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Objectives: To assess the frequency of major complications after multi-probe stereotactic radiofrequency ablation (SRFA) in a large cohort of patients over 15 years and to elucidate risk factors for adverse events.

Materials And Methods: A retrospective study was carried out between July 2003 and December 2018. Seven hundred ninety-three consecutive patients (median 65.

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Background: To evaluate the efficacy, safety and overall clinical outcome of multiprobe SRFA as a treatment for recurrent colorectal liver metastases after hepatic resection (HR).

Methods: A retrospective, single center study carried out between 2006 and 2018. 64 consecutive patients with recurrent or new CRLM after previous HR were treated by SRFA for 217 lesions (median size 2.

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