Andreas Lubienski

CT-Guided Radiofrequency Ablation in Patients with Hepatic Metastases from Breast Cancer

The purpose of this study was to evaluate technical success, technique effectiveness, and survival following radiofrequency ablation for breast cancer liver metastases and to determine prognostic factors. Forty-three patients with 111 breast cancer liver metastases underwent CT-guided percutaneous radiofrequency (RF) ablation. Technical success and technique effectiveness was evaluated by performing serial CT scans. We assessed the prognostic value of hormone receptor status, overexpression of human epidermal growth factor receptor 2 (HER2), and presence of extrahepatic tumor spread. Survival rates were calculated using the Kaplan–Meier method. Technical success was achieved in 107 metastases (96%). Primary technique effectiveness was 96%. During follow-up local tumor progression was observed in 15 metastases, representing a secondary technique effectiveness of 86.5%. The overall time to progression to the liver was 10.5 months. The estimated overall median survival was 58.6 months. There was no significant difference in terms of survival probability with respect to hormone receptor status, HER2 overexpression, and presence of isolated bone metastases. Survival was significantly lower among patients with extrahepatic disease, with the exception of skeletal metastases. We conclude that CT-guided RF ablation of liver metastases from breast cancer can be performed with a high degree of technical success and technique effectiveness, providing promising survival rates in patients with no visceral extrahepatic disease. Solitary bone metastases did not negatively affect survival probability after RF ablation.

Retained surgical sponge with migration into the duodenum and persistent duodenal fistula.

Abstract. Migration of a retained surgical sponge into the bowel is a rare cause of bowel obstruction. Thus far, there have not been any reports that the site of initial migration of the sponge was identified by imaging studies or surgical exploration because the onset of symptoms is usually delayed. Unique about the case presented herein is that a barium meal follow-through study revealed a duodenual fistula that had developed after uneventful cholecystectomy due to a retained surgical sponge that had migrated into the duodenum and obstructed the distal jejunum. Imaging findings are presented and discussed.

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. Tyrodes solution, oxygenated and heated to 36.5°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.

Experimental functional analysis of self-expanding stents using a new developed ex vivo model.

Objective:To modify an ex vivo test procedure for balloon expandable stents as a means to evaluate the mechanical properties of self-expanding stents. Methods:Ten stents each of 7 different stent models measuring 10 mm in diameter (LUMINEXX Vascular Stent/Memotherm-FLEXX Vascular Stent [identical to Bard], Jostent SelfX, Jostent SelfX high radial force [Jomed], sinus-Repo stent, sinus-SuperFlex stent [Optimed], S.M.A.R.T. stent [Cordis], and Easy Wallstent [Boston Scientific]) were implanted in common iliac arteries taken from cadavers (n = 35). They were randomized to either the right or left bifurcation. The vessels were then maintained at 37°C for 24 hours in a special solution that inhibited autolysis, making it possible for the stents to expand. Afterward, they were filled with silicone caoutchouc. After another 24 hours, the vessel walls and stents were removed from the hardened casts. By means of fine analytic measurements, we demonstrated that the volume of a hardened cast formed in the stent cylinder is an indirect but precise measure of the radial force of a stent. Furthermore, using correlation analysis, we examined the relationship between radial force and vessel diameter as well as that between radial force and the degree of arteriosclerosis. Results:The differences between the actually measured volumes, ie, radial strength, (1 cm stent length) of the various stent models (LUMINEXX/Memotherm-FLEXX: 0.6198 mL ± 0.1537 mL; Jostent SelfX: 0.6756 mL ± 0.1298 mL; Jostent SelfX high radial force: 0.6321 mL ± 0.1817 mL; sinus-Repo stent: 0.5508 mL ± 0.1485 mL; sinus-SuperFlex stent: 0.6174 mL ± 0.0953 mL; S.M.A.R.T. stent: 0.5627 mL ± 0.1270 mL; and Easy Wallstent: 0.5613 mL ± 0.1019 mL) were not statistically significant (P > 0.05), but the differences to the theoretically possible volumes that we had previously calculated were highly significant (P < 0.05). Correlation and regression analyses demonstrated a significantly stronger relationship between stent volume and vessel diameter than between stent volume and degree of arteriosclerosis. Conclusion:The modification of our ex vivo model of balloon-expandable stents now makes it possible for researchers to obtain comparable and realistic values for both the radial force and the expansion of self-expanding stents under realistic conditions. Our methods should therefore be employed as an additional procedure to optimize the preclinical evaluation of new stent during certification.

Radiofrequency Ablation (RFA): Development of a Flow Model for Bovine Livers for Extensive Bench Testing

PurposeTo develop a flow model for bovine livers for extensive bench testing of technical improvements or procedure-related developments of radiofrequency ablation excluding animal experiments.MethodsThe perfusion of bovine livers directly from the slaughterhouse was simulated in a liver perfusion tank developed for the experimental work. The liver perfusion medium used was a Tyrode solution prepared in accordance with physiologic criteria (as for liver transplants) which was oxygenated by an oxygenator and heated to 36.5°C. Portal vein circulation was regulated via a flow- and pressure-controlled pump and arterial circulation using a dialysis machine. Flow rate and pressure were adjusted as for the physiology of a human liver converted to bovine liver conditions. The fluid discharged from the liver was returned into the perfusion system through the vena cava. Extendable precision swivel arms with the radiofrequency probe attached were mounted on the liver perfusion tank. RFA was conducted with the RF3000 generator and a 2 cm LeVeen needle (Boston Scientific, Ratingen, Germany) in a three-dimensional grid for precise localization of the generated thermolesions.ResultsFour bovine livers weighing 8.4 ± 0.4 kg each were prepared, connected to the perfusion system, and consecutively perfused for the experiments. Mean arterial flow was 569 ± 43 ml/min, arterial pressure 120 mmHg, portovenous flow 1440 ± 305 ml/min, and portal pressure 10 mmHg. Macroscopic evaluation after the experiments revealed no thrombi within the hepatic vessels. A total of 136 RF thermolesions were generated with an average number of 34 per liver. Mean RF duration was 2:59 ± 2:01 min:sec with an average baseline impedance of 28.2 ± 3.4 ohms. The mean diameter of the thermolesions along the puncture channel was 22.98 ± 4.34 mm and perpendicular to the channel was 23.27 ± 4.82 mm.ConclusionExtracorporeal perfusion of bovine livers with consecutive standardized RF ablation was feasible. The bovine liver flow model seems to allow extensive, standardized evaluation of technical or procedure-related developments of RF systems.

Interventions for benign biliary strictures

Due to their potential for serious consequences, even including biliary liver cirrhosis, benign biliary strictures pose a considerable diagnostic and therapeutic challenge. In addition to inflammatory disease or an acute liver injury, iatrogenically caused biliary strictures following hepatobiliary surgery represent in 95% of cases the main cause for all benign entities. The diagnosis should be determined noninvasively with magnetic resonance cholangiopancreaticography (MRCP). Invasive techniques such as ERCP or percutaneous transhepatic cholangiography (PTC) should be reserved for unclear cases and first performed before the scheduled intervention. Depending on the site and cause of the stricture, surgical and interventional procedures are employed in the treatment of biliary strictures. The best results are obtained in short-segment strictures of the main bile duct. Interventional methods such as balloon dilation and/or stent application with concomitant drain insertion achieve patency rates of up to 75% after 5 and 55% after 12 years with a total complication rate of 5-8%. Due to the fact that most of the cases involve cicatricial fibroses, predisposition for recurrence of biliary strictures after interventional therapy can be very high, ranging up to 66% depending on the localization.

Stellenwert der Multislice-CT bei der Diagnostik der Lungenembolie

Multislice computed tomography (MSCT) of the pulmonary arteries has overcome the limitations of single-slice CT and is accepted as the sole reference standard for imaging pulmonary embolism (PE) in many institutions. This technique provides the opportunity of efficient risk stratification to enable adequate differential therapy. With a low or intermediate pretest probability and a negative CT angiography (CTA), relevant PE can be ruled out safely. In >30% further diagnoses other than pulmonary embolism, e.g., pneumonia or aortic aneurysm, can be established on the basis of thoracic CTA. This article discusses the present role of MSCT in diagnostic imaging of PE and provides optimized acquisition protocols as well as practical aspects for secondary image reconstruction. Examples of typical imaging features of PE are shown. Diagnostic algorithms for daily emergency practice are discussed with respect to artifacts and pitfalls in image interpretation.

Percutaneous Alcohol Instillation

As yet there is no general consensus on a common rational therapeutic approach to hepatocellular carcinoma (HCC). Therefore, treatment strategies for HCC vary throughout the world due to geographical differences in the incidence and presentation of the disease and the treatment options available. Several treatment guidelines have been published by the European Association for the Study of the Liver (EASL) (Bruix et al. 2001), with the Barcelona Clinic Liver Cancer (BCLC) staging recommendation being the most accepted (Fig. 3.2.1) (Mor et al. 1998; Sala et al. 2004). It links tumoral stage with treatment strategy, and is aimed at incorporating an estimation of the prognosis and potential treatment advancements in a single unified proposal (Sala et al. 2004). According to these guidelines percutaneous alcohol instillation (PAI) has a place in the treatment strategy of HCC, generally as a second choice when surgical techniques are precluded, such as in patients with early-stage tumors; nevertheless, in some centers in Italy and Japan PAI is used as a first-line treatment option (Llovet et al. 2003).

Bildgebungsverfahren bei neuroendokrinen und mesenchymalen Tumoren des Gastrointestinaltrakts

Neuroendocrine tumors (NET) are rare, and the majority of gastrointestinal NET arise in the small bowel while pancreatic NET originate in the islet cells. The goal of modern imaging strategies is to establish an early and timely diagnosis besides local staging and detection of metastatic spread. This overview provides an assessment of CT, MRI, somatostatin receptor scintigraphy (SRS) and PET by means of compared detection rates and sensitivities. The mean detection rate and sensitivity of CT and MRI in the diagnosis of extrapancreatic NET is documented to be 80% on average. In the detection of pancreatic insulinomas and gastrinomas the sensitivity of MRI (85-100%) is reported to be higher than that of CT (69-82%). 111In-octreotide SRS provides detection rates of 75-100% while (18F-)FDG-PET showed limited values of 25-73%. Gastrointestinal stromal tumors (GIST) account for most of the mesenchymal gastrointestinal tumors, and contrast-enhanced CT is the accepted standard modality for the staging of GIST. If suspicion of metastatic spread is raised, complementary PET is indicated to detect foci of increased FDG metabolism. Furthermore, PET is the modality of choice for early response monitoring of imatinib. This overview illustrates the diagnostic strategies and imaging features of gastroenteropancreatic NET and GIST using different imaging modalities by means of the actual literature and own results.

Interventionen bei benignen Gallengangstenosen

Due to their potential for serious consequences, even including biliary liver cirrhosis, benign biliary strictures pose a considerable diagnostic and therapeutic challenge. In addition to inflammatory disease or an acute liver injury, iatrogenically caused biliary strictures following hepatobiliary surgery represent in 95% of cases the main cause for all benign entities. The diagnosis should be determined noninvasively with magnetic resonance cholangiopancreaticography (MRCP). Invasive techniques such as ERCP or percutaneous transhepatic cholangiography (PTC) should be reserved for unclear cases and first performed before the scheduled intervention. Depending on the site and cause of the stricture, surgical and interventional procedures are employed in the treatment of biliary strictures. The best results are obtained in short-segment strictures of the main bile duct. Interventional methods such as balloon dilation and/or stent application with concomitant drain insertion achieve patency rates of up to 75% after 5 and 55% after 12 years with a total complication rate of 5-8%. Due to the fact that most of the cases involve cicatricial fibroses, predisposition for recurrence of biliary strictures after interventional therapy can be very high, ranging up to 66% depending on the localization.