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Thomas Helmberger

Publications and source records attributed to Thomas Helmberger.

16 recordsLinked to original sources
PubMed2006

Mid-term results in otherwise treatment refractory primary or secondary liver confined tumours treated with selective internal radiation therapy (SIRT) using (90)Yttrium resin-microspheres.

The purpose was to determine the response and survival and to analyse the feasibility of single-session, whole-liver SIRT in patients with non-resectable, otherwise non-responding liver cancer. Thirty-nine patients qualified for SIRT. Eighteen patients suffered from colorectal-cancer metastases (CRC), breast-cancer metastases (MBC, 7), HCC (5) and other tumours (9). Response was assessed by tumour-markers and CT-imaging. At 2-4, 5-7 and 8-9 months follow-up in 3/17, 5/15 and 5/10 of CRC-patients CEA-levels were higher than before. In the MBC group 1-3 and 4-6 months after SIRT tumour-marker-levels were higher in 2/6 and 3/3 patients, respectively. In all HCC-patients AFP-levels dropped 1-3 months after SIRT. Using RECIST, in the CRC-group progressive liver disease (PD) was found in 4/17, 2/12, 2/10 and 2/5 patients at 2-4, 5-8, 9-10 and 12-14 months follow-up. Concerning MBC, after 3 months 7/7 patients presented with stable-disease (SD) or partial-response (PR). At 5-6 months, 1/5 patients showed PD. All HCC-patients showed SD/PR at 2-3 months with no PD at 5-8 months. In the mixed-group 5/6 patients presented with SD/PR at 3-4 months and with SD in 2/3 patients at 5-6 months. The median time-to-PD was 6.5, 8.5 and 8 months for the CRC-, MBC- and mixed-group, respectively. SIRT is a promising, liver-targeted approach for patients with otherwise treatment-refractory liver tumours.

Brachytherapy↗
PubMed2006

Liver metastases.

Explore the source record for details and available documents.

Catheter Ablation↗
PubMed2006

Effects of vascular perfusion on coagulation size in radiofrequency ablation of ex vivo perfused bovine livers.

OBJECTIVES: A standardized perfused ex vivo bovine liver model was used to evaluate the effect of organ perfusion on coagulation size and energy deposition during radiofrequency ablation (RFA) procedures. MATERIALS AND METHODS: Bovine livers were perfused in a tank after rinsing the prepared liver vessels with anticoagulants. Tyrode's solution, oxygenated and heated to 36.5 degrees C, was used as perfusion medium. A flow and pressure controlled pump regulated Portal vein circulation; a dialysis machine provided pulsatile arterial circulation. Impedance-guided radiofrequency ablations were performed with 4-cm LeVeen electrodes with and without underlying liver perfusion. Two-dimensional diameters (Dv, Dh) of each ablation area were measured after dissecting the livers. RESULTS: In 4 bovine livers weighing 8.85 +/- 0.83 kg per organ (min, 7.7 kg; max, 9.7 kg) altogether 40 RF ablations were performed. A total of 20 ablations were generated with underlying liver perfusion (group 1) and 20 ablations with no liver perfusion (group 2). In group 1, Dv was 28.4 +/- 5.3 mm, Dh 38.6 +/- 7.8 mm, and energy deposition 36.9 +/- 18.0 kJ. The 20 ablation areas generated without liver perfusion displayed statistically significant differences, with Dv being 35.7 +/- 6.5 mm (P = 0.001), Dh 49.5 +/- 9.4 mm (P = 0.001), and energy deposition 25.5 +/- 13.0 kJ (P = 0.018). CONCLUSION: The model reproduced the cooling effect of perfused tissue during RFA. The ablation areas produced under perfusion conditions had smaller diameters despite longer exposure times and higher energy deposition.

Animals↗
PubMed2005

Selective internal radiation therapy with SIR-Spheres in patients with nonresectable liver tumors.

AIM: Transarterial embolization of branches of the hepatic artery with biocompatible 90Y-labeled microspheres (SIR-Spheres) is a local treatment modality for patients with liver tumors, which, most recently, has become available in Europe. The aim of this study was to evaluate the feasibility and efficacy of this selective internal radiation therapy (SIRT). METHODS: Twenty-three patients with nonresectable hepatic metastases or hepatocellular carcinoma nonresponding to polychemotherapy and/or other local treatment were treated with SIRT. SIR-Spheres (mean activity, 2270 MBq) were administered by gentle intra-arterial infusion in the hepatic artery. A follow-up was documented by fluorodeoxyglucose-positron emission tomography (FDG-PET), course of tumor markers, and computed tomography (CT). RESULTS: Common minor side-effects were abdominal pain, nausea, and fever. Mild pancreatitis and peptic ulceration were observed once each. Currently, all patients are still alive, with survival times ranging from 11 to 518 days from SIRT up to the present. Three-month follow-up investigations are available in 13 of 23 patients, which, so far, are showing a marked decrease of FDG uptake, a drop of tumor markers, and unchanged or slightly decreasing lesion size (CT) in 10 of 13 patients. Two patients showed stable findings, while another patient showed progressive disease. Long-term follow-up investigations are available in 2 of 23 patients, showing hepatic and extrahepatic progression 6 and 9 months after SIRT. CONCLUSIONS: Our initial experience confirms that SIRT is a promising local therapeutic approach in patients with nonresectable liver tumors which is feasible and has an acceptable toxicity profile. Prospective data on comparing this treatment alone or in combination with other modalities are needed to answer whether long-term survival in this unfavorable stage of disease can be markedly improved.

Adult↗
PubMed2004

Antibody-positive paraneoplastic neurologic syndromes: value of CT and PET for tumor diagnosis.

OBJECTIVE: To assess use of whole-body 18F fluoro-2-deoxy-glucose (FDG)-PET and CT for diagnosing tumor in patients with antibody-positive paraneoplastic neurologic syndromes (PNS). METHODS: In order to directly compare CT and FDG-PET imaging in patients with various antineuronal antibodies, the authors performed in parallel CT scanning and FDG-PET in a series of 13 consecutive patients (9 women, 4 men, aged 59 +/- 14 years) with positive antineuronal antibodies (anti-Hu: 8, anti-Yo: 4, anti-Tr: 1) in whom the authors were searching for a tumor or tumor recurrence. RESULTS: A new tumor or tumor recurrence was found in 10/13 patients (5 small cell lung cancer, 2 ovarian cancer, and 1 each neuroblastoma, Hodgkin's lymphoma, and lymph node metastasis of adenocarcinoma). All tumors except one with good clinical evidence for small cell lung cancer were confirmed histologically. For detection of tumor or tumor recurrence, CT was positive in 3/10 patients (sensitivity of 30%), and FDG-PET in 9/10 (sensitivity of 90%, difference between methods p < 0.01), but the combination of both methods showed a sensitivity of 100%. CONCLUSIONS: FDG-PET imaging is useful in tumor screening of patients with antineuronal antibodies, but should be complemented by CT scanning to increase sensitivity and accuracy of tumor diagnosis.

Adenocarcinoma↗
PubMed2004

Cross-sectional imaging of biliary tumors: current clinical status and future developments.

Extrahepatic cholangiocarcinoma, including hilar cholangiocarcinoma, is a relatively rare diagnosis. However, it frequently has been associated with major problems in diagnostics and clinical management from its first comprehensive description by Klatskin up until today. In this article, cholangiocarcinoma, representing the most common biliary tumor, as well as the differential diagnoses of benign and malignant biliary obstruction, will be discussed. The latest improvements of cross-sectional imaging modalities (sonography, CT, MRI and PET) and their diagnostic values for detection and staging will be displayed. A practical imaging-based diagnostic approach to obstructive biliary disease will be proposed.

Bile Duct Neoplasms↗
PubMed2004

Magnetic resonance imaging characteristics of six radiofrequency electrodes in a phantom study.

PURPOSE: To evaluate and compare visibility and artifacts in magnetic resonance (MR) compatible radiofrequency (RF) electrodes for MR-guided RF ablation. MATERIAL AND METHODS: Six different MR compatible electrodes for RF ablation including two internally cooled single needles, one internally cooled cluster needle, two expandable needles and one perfused needle were tested in a phantom study at 0.2 Tesla and at 1.5 Tesla field strength. Fluoroscopic, T1- and T2-weighted fast spin echo (FSE) and gradient echo (GE) sequences, which are usually used for MR-guided interventions, were evaluated. Qualitative and quantitative evaluations were performed. Length, width, noise, tip artifacts, global artifacts and global visualization of the RF electrodes that showed all sequences at different angles. RESULTS: Qualitative analysis showed that electrodes were well visualized at all angles and sequences and on both MR imagers. Quantitative analysis showed that artifact-induced widening of the shaft was increased in all electrodes by: a). use of fluoroscopic sequences, GE sequences, and fat saturation, b). increasing the angle between the needle and main magnetic field, and c). high field strength (1.5 T). Expandable needles produced fewer tip artifacts but broader signal voids along the shaft compared to nonexpandable needles. Cluster electrodes produced less widening than the other electrodes. CONCLUSION: Visibility and artifacts in all six MR compatible RF electrodes are satisfactory and these electrodes could be used for MR-guided radiofrequency ablation procedures.

Artifacts↗
PubMed2002

Detection of malignant hepatic lesions before orthotopic liver transplantation: accuracy of ferumoxides-enhanced MR imaging.

OBJECTIVE: The purpose of this study was to evaluate the diagnostic accuracy of ferumoxides-enhanced MR imaging for screening malignant hepatic lesions before orthotopic liver transplantation. MATERIALS AND METHODS: The study comprised 48 patients who underwent MR imaging within 6 months before transplantation. Imaging techniques included unenhanced and ferumoxides-enhanced T1-weighted gradient-echo and T2-weighted fast spin-echo sequences and ferumoxides-enhanced T2(*)-weighted gradient-echo sequences. Qualitative and quantitative analyses were performed; the gold standard was the histopathologic reports of explanted livers. RESULTS: Twenty patients had malignant hepatic lesions, and 24 hepatocellular carcinomas were histopathologically proven. The mean area under the receiver operating characteristic curve and the mean sensitivity were significantly greater for the image sets with ferumoxides-enhanced gradient-echo sequences than for those without these sequences. The mean sensitivity and specificity of all sequences were 85% and 74% on a per-patient basis, respectively. The mean contrast-to-noise ratio was significantly greater for the ferumoxides-enhanced T2(*)-weighted gradient-echo sequences than for any other sequences and for the ferumoxides-enhanced T1-weighted gradient-echo sequences than for unenhanced sequences and the ferumoxides-enhanced T2-weighted fast spin-echo sequences. CONCLUSION: Ferumoxides-enhanced gradient-echo sequences improved the diagnostic accuracy and the sensitivity for detecting malignant hepatic lesions in patients with end-stage cirrhosis of the liver. However, the specificity was not improved even after the administration of ferumoxides because of the false-positive lesions that were mainly the result of fibrotic changes.

Adult↗
PubMedDate not supplied

Radiation dose to the radiologist's hand during continuous CT fluoroscopy-guided interventions.

Computed tomography fluoroscopy (CT fluoroscopy) enables real-time image control over the entire body with high geometric accuracy and, for the most part, without significant interfering artifacts, resulting in increased target accuracy, reduced intervention times, and improved biopsy specimens [1--4]. Depending on the procedure being used, higher radiation doses than in conventional CT-supported interventions might occur. Because the radiologist is present in the CT room during the intervention, he is exposed to additional radiation, which is an important aspect. Initial experience with CT fluoroscopically guided interventions is from the work of Katada et al. in 1994 [5] and only relatively few reports on radiation aspects in CT fluoroscopy are found in the literature [1, 2, 6--11]. To date, there are no reported injuries to patients and radiologists occurring with CT fluoroscopy. The time interval since the wide use of CT fluoroscopy is too short to have data on late effects to the operator using CT fluoroscopy on a daily basis. In addition, the spectrum of CT fluoroscopically guided interventional procedures will expand and more sophisticated procedures requiring longer fluoroscopy times will be performed. Thus, effective exposure reduction is very important. The purpose of our study was to assess the radiation dose to the operator's hand by using data from phantom measurements. In addition, we investigated the effect of a lead drape on the phantom surface adjacent to the scanning plane, the use of thin radiation protective gloves, and the use of different needle holders.

Adult↗
PubMedDate not supplied

CT/fluoroscopy-guided transthoracic needle biopsy: sensitivity and complication rate in 98 procedures.

PURPOSE: The purpose of this study was to evaluate CT/fluoroscopy (CTF)-guided core needle biopsies (CNBs) in the thorax. METHOD: Ninety-eight biopsies were performed using a core biopsy needle (18G) with a reusable biopsy gun under CT/F. All results were compared to surgery plus histology or to clinical follow-up of >12 months. Sensitivity, specificity, and negative predictive value (NPV) were calculated. RESULTS: For pulmonary biopsies, sensitivity was 94%, specificity 100%, and NPV 73%; no significant correlation between the pneumothorax rate and the intrathoracic penetration depth was found. For biopsies of the mediastinum and pleura, sensitivities were 87 and 80%, respectively; specificity was 100% in both locations. A pneumothorax occurred in 21%, a pneumothorax requiring drainage in 2.0%. CONCLUSION: CT/F-guided CNB is a reliable method to obtain thoracic biopsies, with a complication rate of 2.0%.

Adult↗
PubMedDate not supplied

Cross-sectional imaging findings in congenital intestinal lymphangiectasia.

A 37-year-old woman presented with an 18 month history of recurrent severe abdominal pain, recurrent diarrhea since her second year of life, and mild peripheral edema. CT and more clearly MRI revealed signs of small bowel and mesenterial edema with partial tubular appearance, which correlated well with the histopathologic findings shown in duodenal biopsy. This is the first report of MR findings in congenital intestinal lymphangiectasia with correlation with other imaging modalities.

Abdominal Pain↗
PubMedDate not supplied

Large core biopsy of the pancreas under CT fluoroscopy control: results and complications.

PURPOSE: The objective of this study was to evaluate the accuracy and complication rate of CT fluoroscopy-guided percutaneous core biopsies of the pancreas in patients with a suspected pancreatic neoplasm. MATERIALS AND METHODS: Sixty-three CT-guided biopsies were performed in 57 consecutive patients over a period of 20 months. Forty-nine of the 57 patients had a malignant lesion (85.9%). All procedures were done under CT fluoroscopic guidance. A high-speed biopsy gun with 14, 16, or 18 gauge cutting-type needles was used. Based on final pathologic diagnosis as the standard of reference, the diagnostic efficacy was determined. Complications during and afterward up to the patient's discharge from hospital (mean, 8.1 days; range, 1-48 days) were noted. RESULTS: Core biopsy of the pancreas resulted in a correct diagnosis in 51 of 63 biopsies, yielding a sensitivity for malignancy of 78.1%, a specificity of 100%, a positive predictive value of 100%, and an overall accuracy of 81.0%. One patient of 57 developed an acute pancreatitis related to the biopsy (1.6%). CONCLUSION: CT fluoroscopic-guided core biopsy is a safe and reliable tool for the pretherapeutic evaluation of pancreatic lesions.

Adult↗
PubMedDate not supplied

Pulmonary radiofrequency ablation--an international study survey.

BACKGROUND: The lung is the most common site for primary cancer worldwide as well as being a common site of metastases for various malignancies. Percutaneous radiofrequency ablation (RFA) is rapidly evolving as a new minimally invasive tool for the treatment of pulmonary tumors. PATIENTS AND METHODS: A questionnaire was sent by e-mail to 14 centres around the world, which we knew or thought were performing percutaneous pulmonary RFA, to retrospectively survey their experience in this field including the number of ablations done to date, indications, method, peri- and postprocedural complications. RESULTS: Seven centers reported 493 percutaneous procedures in lung tumors. Two deaths have been reported. Complications were subdivided into major and minor complications. Pneumothorax occurred in up to 30% of interventions with less than 10% requiring intercostal drainage. Pleural effusion requiring aspiration occurred in less than 10% of cases. CONCLUSION: With almost 500 procedures done to date, percutaneous pulmonary RFA appears to be a safe, minimally invasive tool for local pulmonary tumor control with negligible mortality, little morbidity, short hospital stay and gain in quality of life.

Catheter Ablation↗