[Current CO2 angiography]. / Aktuelle CO2-Angiographie.

BACKGROUND: Carbon dioxide (CO2) is a very good and validated alternative to iodine-containing contrast media in diagnostic and interventional angiography. Nevertheless, its routinely use is still limited to specialized centers. OBJECTIVE: The presentation of the current role and limitations of CO2 in diagnostic and interventional angiography (venous and arterial). MATERIAL AND METHODS: A comprehensive review of the literature regarding CO2 angiography (physical features, indications, contraindications, applications) was carried out. RESULTS: The results show that CO2 can be used as a reliable alternative for diagnostic angiography and to support interventions in many arterial and venous vascular territories. An exception is the intra-arterial use of CO2 above the diaphragm due to the risk of severe myocardial and cerebral complications, which represents the most important contraindication. Moreover, due to its very low viscosity, CO2 is more effective than iodine-containing contrast media in detecting bleeding arising from small vessels. CONCLUSION: The CO2 angiography is a safe and effective technique and can be used as valid alternative. In several clinical cases it even offers some advantages compared to iodine-containing contrast media.

ALPPS Procedure in Insufficient Hypertrophy After Portal Vein Embolization (PVE).

BACKGROUND: The main limiting factor for major liver resections is the volume and function of the future remnant liver (FLR). Portal vein embolization (PVE) is now standard in most centers for preoperative hypertrophy of FLR. However, it has a failure rate of about 20-30 %. In these cases, the "Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy" (ALPPS) may represent a suitable and possibly the only alternative. METHODS: We performed a retrospective analysis of nine patients who had ALPPS following an insufficient hypertrophy after PVE. Computed tomography volumetry were performed before and after PVE as well as the first step of ALPPS. Furthermore, complications, 30-day mortality and outcome were analyzed. RESULTS: The FLR volume rose significantly by 77.7 ± 40.7 % (FLR/TLV: 34.9 ± 9.7 %) as early as 9 days after the first stage despite insufficient hypertrophy after preoperative portal vein embolization. Major complications (Grade > IIIb) occurred in 33 % of the patients, and 30-day mortality was 11.1 %. The OS at 1 and 2 years was 78 and 44 %. Four patients are presently still alive at a median of 33.4 (range 15-48) months (survival rate 44.4 %). CONCLUSION: The ALPPS procedure could be a suitable alternative for patients following insufficient PVE or indeed the last chance of a potentially curative treatment in this situation. Nevertheless, the high morbidity and mortality rates and the lack of data on the long-term oncological outcome must also be taken into account.

Vascular closure devices after endovascular procedures in swine: a reliable method?

PURPOSE: To investigate the safety and feasibility of the use of a vascular closure device (VCD) after endovascular procedures in swine. MATERIAL AND METHODS: In a study on endovascular therapy, VCD (StarClose, Abbott Vascular, Il, USA) was used in 20 female swines to achieve immediate hemostasis after percutaneous right femoral artery (FA) access. 10 animals were sacrificed immediately after the study and 10 animals were sacrificed 28 days after the initial study. To ensure complete hemostasis and patency of the femoral artery, a CT-angiography of the puncture site was performed on day 1 (acute and chronic group) and day 28 (chronic group). After the sacrifice, the femoral artery was explanted and examined macroscopically for signs of VCD dysfunction. RESULTS: Technical success rate was 100% with immediate hemostasis being achieved in all animals. No animals showed evidence of hematoma. During explantation, only small traces of coagulated blood were found in the acute group, while there were no signs of hematoma in the chronic group. CT-angiography immediately after VCD application as well as before sacrifice (chronic group) showed patency of the FA in all cases. CONCLUSION: The use of VCD to achieve hemostasis after endovascular studies in swine is feasible and safe.

Comparison of Complications in Patients with Ductal Cholangiocarcinoma (CCC) and Patients with Colorectal Liver Metastases (CRLMs) After Portal Vein Embolization (PVE): A Matched Cohort Study.

PURPOSE: To compare complications in patients with cholangiocarcinoma (CCC) and patients with colorectal liver metastases (CRLMs) after portal vein embolization (PVE) and to identify possible predictive factors. MATERIAL AND METHODS: Retrospective analysis of consecutive patients, who underwent PVE between July 2011 and March 2020. The study groups were matched for sex and age. Multivariable analysis was performed for the endpoints of complications categorized according for their respective effect on surgical treatment: "Minor" complications had no effect on subsequent surgical treatment, while "intermediate" and "severe" complications delayed or prevented surgery. RESULTS: A total of 160 patients with either CCC (n = 80) or CRLMs (n = 80) were included: 34/160 experienced complications: 27 (CCC: 21; CRLMs: 6) "minor", 4 (CCC: 3; CRLMs: 1) "intermediate", and 3 (CCC: 2; CRLMs: 1) "severe" complications respectively (p = .01). Patients with CCC received a biliary drainage 5 days on average before PVE. Baseline bilirubin levels were 1.1 mg/dl in CCC patients and 0.55 mg/dl in CRLMs patients (p < .01). Postinterventional infections were more common in CCC patients. The preintervention future liver remnant volume (odds ratio (OR) 0.93; 95% confidence interval (CI) 0.88-0.99; p = .02), body mass index (OR 1.19; 95% CI 1.04-1.36; p = .01), age (OR 0,91; 95% CI 0.84-0.99; p = .01), chemotherapy before PVE (OR 0.03; 95% CI 0.01-0.23; p < .01) and severe liver steatosis (OR 29.52; 95% CI 1.87-467,13; p = .02) were the only significant predictive factors for the occurrence of (minor) complications. CONCLUSION: PVE can be performed in CCC patients with prior biliary drainage, with similar procedural safety as in patients with CRLMs.

[Electromagnetic navigation of transpedicular punctures: more precise than the standard?]. / Elektromagnetische Navigation transpedikulärer Punktionen: Präziser als der Standard?

AIM: Before clinical implementation of an approved electromagnetic tracking system (CAPPA IRAD EMT) an experimental trial was performed to investigate the accuracy of the system and its safety in application for transpedicular vertebral punctures in comparison to the classical fluoroscopic method. MATERIAL AND METHODS: A total of 110 transpedicular punctures were performed bilaterally using 11 vertebrae of 5 realistic artificial phantoms and 1 pedicle was punctured with the conventional technique using c-arm fluoroscopy and the other with the electromagnetic tracking system. As a target a radiopaque non-ferromagnetic marker was implanted bilaterally in the anterior wall of the vertebrae. For evaluation of the precision the distance from the end of the puncture to the target and the gradual deviation of the actual channel from the ideal trajectory were assessed in three-dimensional computer tomography. Calculations and statistical analysis were performed according to the Wilcoxon test by means of SPSS 16.0.1 for Windows. RESULTS: The mean distance from the target was 6.6 mm (± 3.9 mm standard deviation SD) with electromagnetic navigation compared to 3.2 mm (± 2.8 mm SD) with fluoroscopic assistance and the mean aberration from the ideal trajectory was 18.4° (± 4.6° SD) compared to 6.5° (± 3.5° SD), respectively. The difference of accuracy was highly significant regarding both parameters (p < 0.001). CONCLUSIONS: The minimum requirement for accuracy of transpedicular punctures could not be achieved with electromagnetic navigation. Unless proven otherwise, the lack of accuracy is attributed to unstable referencing. Despite evidence of successful employment for soft tissue punctures the system cannot currently be recommended for osseous applications of the spine.

[Process-oriented cost calculation in interventional radiology. A case study]. / Prozessorientierte Kostenrechnung in der Interventionellen Radiologie. Eine Fallstudie.

PURPOSE: Currently used costing methods such as cost centre accounting do not sufficiently reflect the process-based resource utilization in medicine. The goal of this study was to establish a process-oriented cost assessment of percutaneous radiofrequency (RF) ablation of liver and lung metastases. MATERIAL AND METHODS: In each of 15 patients a detailed task analysis of the primary process of hepatic and pulmonary RF ablation was performed. Based on these data a dedicated cost calculation model was developed for each primary process. The costs of each process were computed and compared with the revenue for in-patients according to the German diagnosis-related groups (DRG) system 2010. RESULTS: The RF ablation of liver metastases in patients without relevant comorbidities and a low patient complexity level results in a loss of EUR 588.44, whereas the treatment of patients with a higher complexity level yields an acceptable profit. The treatment of pulmonary metastases is profitable even in cases of additional expenses due to complications. CONCLUSION: Process-oriented costing provides relevant information that is needed for understanding the economic impact of treatment decisions. It is well suited as a starting point for economically driven process optimization and reengineering. Under the terms of the German DRG 2010 system percutaneous RF ablation of lung metastases is economically reasonable, while RF ablation of liver metastases in cases of low patient complexity levels does not cover the costs.

Stent Graft Placement by Pseudoaneurysm of the Hepatic Arteries: Efficacy and Patency Rate in Follow-up.

PURPOSE: To investigate efficacy and patency status of stent graft implantation in the treatment of hepatic artery pseudoaneurysm. MATERIALS AND METHODS: A retrospective analysis of patients who had undergone endovascular treatment of hepatic artery pseudoaneurysms between 2011 and 2020 was performed. Medical records were examined to obtain patients' surgical histories and to screen for active bleeding. Angiographic data on vascular access, target vessel, material used and technical success, defined as the exclusion of the pseudoaneurysm by means of a stent graft with sufficient control of bleeding, were collected. Vessel patency at follow-up CT was analyzed and classified as short-term (< 6 weeks), mid-term (between 6 weeks and 1 year), and long-term patency (> 1 year). In case of stent occlusion, collateralization and signs of hepatic hypoperfusion were examined. RESULTS: In total, 30 patients were included and of these, 25 and 5 had undergone stent graft implantation and coiling, respectively. In patients with implanted stent grafts, technical success was achieved in 23/25 patients (92%). Follow-up CT scans were available in 16 patients, showing stent graft patency in 9/16 patients (56%). Short-term, mid-term, and long-term short-term stent patency was found in 81% (13/16), 40% (4/10), and 50% (2/4). In patients with stent graft occlusion, 86% (6/7) exhibited maintenance of arterial liver perfusion via collaterals and 14% (1/7) exhibited liver abscess during follow-up. CONCLUSION: Stent graft provides an effective treatment for hepatic artery pseudoaneurysms. Even though patency rates decreased as a function of time, stent occlusion was mainly asymptomatic due to sufficient collateralization.

Dragon 1 Protocol Manuscript: Training, Accreditation, Implementation and Safety Evaluation of Portal and Hepatic Vein Embolization (PVE/HVE) to Accelerate Future Liver Remnant (FLR) Hypertrophy.

STUDY PURPOSE: The DRAGON 1 trial aims to assess training, implementation, safety and feasibility of combined portal- and hepatic-vein embolization (PVE/HVE) to accelerate future liver remnant (FLR) hypertrophy in patients with borderline resectable colorectal cancer liver metastases. METHODS: The DRAGON 1 trial is a worldwide multicenter prospective single arm trial. The primary endpoint is a composite of the safety of PVE/HVE, 90-day mortality, and one year accrual monitoring of each participating center. Secondary endpoints include: feasibility of resection, the used PVE and HVE techniques, FLR-hypertrophy, liver function (subset of centers), overall survival, and disease-free survival. All complications after the PVE/HVE procedure are documented. Liver volumes will be measured at week 1 and if applicable at week 3 and 6 after PVE/HVE and follow-up visits will be held at 1, 3, 6, and 12 months after the resection. RESULTS: Not applicable. CONCLUSION: DRAGON 1 is a prospective trial to assess the safety and feasibility of PVE/HVE. Participating study centers will be trained, and procedures standardized using Work Instructions (WI) to prepare for the DRAGON 2 randomized controlled trial. Outcomes should reveal the accrual potential of centers, safety profile of combined PVE/HVE and the effect of FLR-hypertrophy induction by PVE/HVE in patients with CRLM and a small FLR. TRIAL REGISTRATION: Clinicaltrials.gov: NCT04272931 (February 17, 2020). Toestingonline.nl: NL71535.068.19 (September 20, 2019).

[Interventional radiological therapies in lung oncology]. / Interventionell-radiologische Therapien in der pneumologischen Onkologie.

Interventional radiological procedures for the treatment of primary and secondary pulmonary malignancies have become increasingly important. In addition to thermally ablative treatment, selective chemoembolisation by a vascular access allows localised therapy. These treatments are considered to be palliative for patients in a reduced general condition which does not allow systemic chemotherapy. In functionally inoperable patients especially the ablative procedures are potentially curative alternatives to surgery. This article provides an overview of the currently used interventional radiological procedures in lung oncology and assesses their importance. Further studies are needed to show whether interventional radiological procedures, which are promising due to their favourable risk-benefit ratio, may represent an alternative to radiotherapy or be effective in multimodal approaches.

Correlation Between Sarcopenia and Growth Rate of the Future Liver Remnant After Portal Vein Embolization in Patients with Colorectal Liver Metastases.

PURPOSE: To investigate whether sarcopenia and myosteatosis correlate with the degree of hypertrophy (DH) and kinetic growth rate (KiGR) of the future liver remnant (FLR) in patients with colorectal liver metastases undergoing portal vein embolization (PVE) in preparation for right hepatectomy. MATERIALS AND METHODS: Forty-two patients were included. Total liver volume and FLR volume were measured before and 2-4 weeks after PVE. KiGR of the FLR was calculated. Sarcopenia was assessed using the total psoas muscle volume (PMV), the psoas muscle cross-sectional area (PMCS) and the total skeletal muscle index (L3SMI) at the level of 3rd lumbar vertebra. Degree of myosteatosis was assessed by mean muscle attenuation at L3 (L3MA). Correlations between muscle indices and DH and KiGR were assessed using simple linear regression analyses. RESULTS: Mean DH was 8.9 ± 5.7%, and mean KiGR was 3.6 ± 2.3. Mean PMV was 55.56 ± 14.19 cm3/m3, mean PMCS was 8.76 ± 2.3 cm2/m2, mean L3SMI was 45.6 ± 9.89 cm2/m2, and mean L3MA was 27.9 ± 18.6 HU. There was a strong positive correlation between PMV and DH (R = 0.503, p = 0.001) and PMV and KiGR (R = 0.545, p < 0.001). Furthermore, there was a moderate correlation between PMCS and KiGR (R = 0.389, p = 0.014). L3SMI and L3MA were neither associated with DH (p = 0.390 and p = 0.768, respectively) nor with KiGR (p = 0.188 and p = 0.929, respectively). CONCLUSION: We identified a positive correlation between PMV and PMCS, as markers for sarcopenia, and the KiGR of the FLR after PVE. PMV and PMCS might therefore aid to identify patients who are poor candidates for FLR augmentation using PVE alone.

Short-Term Oral Sorafenib for Therapy of Intratumoral Shunts of Hepatocellular Carcinoma to Enable Intraarterial Treatment.

INTRODUCTION: Significant intratumoral shunts between tumor-supplying arteries and portal or liver veins are a contraindication for transarterial therapy of HCC because interventional treatment of these shunts is frequently insufficient. Sorafenib has anti-angiogenic effects and is indicated for palliative treatment of patients with HCC. Here, we report our experience with the use of sorafenib for the closure of intratumoral shunts in patients scheduled for transarterial therapy of HCC. MATERIALS AND METHODS: Three patients with HCC, aged 65, 82 and 79 years, exhibited a significant intratumoral shunting from tumor artery to portal (n = 1) or liver veins (n = 2). In all cases, intratumoral shunting had already been suspected based on pre-interventional CT angiography, and DSA confirmed the shunt. Oral sorafenib (800 mg/day) was administered for at least four weeks, only and specifically to occlude the shunt. Hereafter, patients were re-evaluated by CT and DSA. RESULTS: All patients tolerated the full prescribed dose for at least 4 weeks. In one case, therapy was prolonged with an adapted dose (400 mg/day) due to sorafenib-related hand-foot syndrome. After sorafenib treatment, CT and DSA confirmed a complete closure of intratumoral shunts for all patients. No tumor progression was observed. All three patients hereafter underwent successful transarterial treatment by TACE (n = 2) or TARE (n = 1) without complications. Progression-free survival according to mRECIST was 501, 397 and 599 days, respectively. CONCLUSION: Even short-term oral sorafenib seems to effectively close intratumoral shunts in patients with HCC and thus might enable transarterial treatment of these patients.

Multipolar hepatic radiofrequency ablation using up to six applicators: preliminary results.

PURPOSE: To evaluate the clinical feasibility and safety of hepatic radiofrequency (RF) ablation using a multipolar RF system permitting the simultaneous use of up to six electrodes. MATERIALS AND METHODS: Ten patients (3 female, 7 male, mean age 61) suffering from 29 hepatic metastases (range: 1 - 5) of different tumors were treated with a modified multipolar RF system (CelonLab Power, Celon Medical Instruments, Teltow, Germany) operating four to six needle-shaped internally cooled RF applicators. The procedure duration, applied energy and generator output were recorded during the intervention. The treatment result and procedure-related complications were analyzed. The achieved coagulation volume was calculated on the basis of contrast-enhanced CT scans 24 hours after RF ablation. RESULTS: Complete tumor ablation was achieved in all cases as determined by the post-interventional lack of contrast enhancement in the target region using four applicators in five patients, five applicators in one patient and six applicators in four patients. A mean energy deposition of 353.9 +/- 176.2 kJ resulted in a mean coagulation volume of 115.9 +/- 79.5 cm (3). The mean procedure duration was 74.9 +/- 21.2 minutes. Four patients showed an intraabdominal hemorrhage which necessitated further interventional treatment (embolization; percutaneous histoacryl injection) in two patients. CONCLUSION: Multipolar RF ablation of hepatic metastasis with up to six applicators was clinically feasible. In our patient population it was associated with an increased risk of intraabdominal bleeding probably due to the multiple punctures associated with the use of multiple applicators.

Fluid-modulated bipolar radiofrequency ablation: an ex-vivo evaluation study.

BACKGROUND: The effect of radiofrequency ablation (RFA) can be modulated by fluid injection. PURPOSE: To evaluate the potential of different fluids to modulate the effect of bipolar RFA in an ex-vivo liver model. MATERIAL AND METHODS: A bipolar RFA system with an internally cooled needle-shaped applicator (20-mm active tip) was used to induce coagulation lesions in ex-vivo porcine liver. Prior to the ablation procedure, 1-ml samples of seven different fluids were injected (0.9% saline, gadopentetate dimeglumine, ioxithalamate, 10% hydroxyethyl starch, 5% glucose, 95% ethanol, distilled water). Each fluid was used for five RF ablations. During the procedure, applied energy, impedance, and time were recorded. Additionally, temperature was measured at a fixed distance of 0.5 and 1.0 cm from the RF probe. Generator output was set to 20 W, as recommended by the vendor. Five ablation procedures without fluid injection served as the reference standard. The lesion diameters were measured, and volume and an efficiency index (coagulation volume/procedure duration) calculated and compared (ANOVA, Student-Newman-Keuls test). RESULTS: In comparison to the reference standard, fluid injection resulted in an enlargement of mean coagulation volume for all fluids. In comparison to RF ablation alone (1.42+/-0.33 cm(3)), significant increase (P<0.001) of lesion size was found using gadopentetate dimeglumine, hydroxyethyl starch, glucose, and ethanol. The largest lesions were generated using preinjection of hydroxyethyl starch. Most energy could be applied after injection of glucose. Comparing the efficiency index, no statistically significant differences were found. CONCLUSION: Besides the modulation of the electrical conductivity, the increase in thermal conductivity also contributes to the enhancement of RFA by the injection of the tested fluids. Further studies are needed to evaluate this effect for larger injection volumes under in-vivo conditions.

[Fluid-modulated RF ablation: in-vitro experiments]. / Flüssigkeitsmodulierte RF-Ablation: In-vitro-Experimente.

PURPOSE: To evaluate the potential of different fluids to enhance the effect of radiofrequency ablation. MATERIALS AND METHODS: A bipolar radiofrequency system with an internally cooled needle electrode was used to heat three samples of 16 different fluids. Each sample had a volume of 20 ml. The generator output was set to 20 watt as recommended by the vendor. Energy was applied until the temperature of the sample reached 80 degrees C or the duration of heating exceeded 30 minutes. If a fluid was not able to be heated because the resistance was too high, 15 ml of the fluid were mixed with 5 ml of a 1-mol saline solution. During energy deposition, the temperature was measured every 15 seconds. The applied energy, impedance, resistance, voltage and flowing current were recorded continuously. RESULTS: The ionic contrast agent Telebrix Gastro was heated to 80 degrees C within 620 +/- 95 seconds which was the shortest time needed. It was not possible to heat the contrast agents Solutrast 300, Isovist 240, Gadovist and Lipiodol as well as a 40 % glucose solution and 95 % ethanol. The longest time was needed to heat the 40 % glucose solution + the 1-mol saline solution (1755 +/- 26 seconds). The correlation coefficients (Pearson) showed only a marginal connection between resistance and maximum temperature (r=0.52) and duration for heating up to 80 degrees C, respectively (r=- 0.54). The same is true for the connection between impedance and maximum temperature (r=0.52) as well as duration for heating up to 80 degrees C (r=- 0.57). CONCLUSION: The selection of an appropriate fluid allows an increase in the effect of radiofrequency ablation or the generation of a protective effect. Especially HAES, Magnevist and Telebrix Gastro are suitable for enhancing heating. Glucose solution or non-ionic contrast agents could be used to generate a protective effect during radiofrequency ablation. The heating of fluids by means of a bipolar radiofrequency ablation system is not only influenced by the electric properties but also by other parameters such as the specific heat capacity.

Impact of Preoperative Three-Dimensional Computed Tomography Cholangiography on Postoperative Resection Margin Status in Patients Operated due to Hilar Cholangiocarcinoma.

INTRODUCTION: The purpose of this study was to analyse the value of 3-dimensional computed tomography cholangiography (3D-ERC) compared to conventional retrograde cholangiography in the preoperative diagnosis of hilar cholangiocarcinoma (HC) with special regard to the resection margin status (R0/R1). PATIENTS AND METHODS: All hepatic resections performed between January 2011 and November 2013 in patients with HC at the Department of General, Visceral and Transplant Surgery of the RWTH Aachen University Hospital were analysed. All patients underwent an ERC and contrast-enhanced multiphase CT scan or a 3D-ERC. RESULTS: The patient collective was divided into two groups (group ERC: n = 17 and group 3D-ERC: n = 16). There were no statistically significant differences between the two groups with regard to patient characteristics or intraoperative data. Curative liver resection with R0 status was reached in 88% of patients in group ERC and 87% of patients in group 3D-ERC (p = 1.00). We could not observe any differences with regard to postoperative complications, hospital stay, and mortality rate between both groups. CONCLUSION: Based on our findings, preoperative imaging with 3D-ERC has no benefit for operative planning and R0 resection status. It cannot replace the exploration by an experienced surgeon in a centre for hepatobiliary surgery.

[Oligometastasized stage IV colorectal cancer : Surgical resection and local ablative procedures]. / Oligometastasierung beim kolorektalen Karzinom im Stadium IV : Chirurgie und lokal ablative Verfahren.

BACKGROUND: By the intensified combination of systemic, surgical and local ablative therapies a significant improvement in therapy results for metastasized colorectal cancer has been achieved in the last decade. Downstaging with subsequent resection is nowadays a standard for oligometastasized primarily unresectable colorectal cancer. MATERIAL AND METHODS: The value of combining resection and local ablation is unclear; therefore, this article gives an overview of the available literature dealing with the combination of surgery and local ablative methods for oligometastasized stage IV colorectal cancer. RESULTS: The best results were obtained following surgical resection alone. Whereas nowadays cryoablation is of minor importance, the most successful results are achieved following local ablative methods by radiofrequency and microwave ablation. In the future irreversible electroporation will be the most promising local ablative method. A combination of surgical resection and local ablation appears to be rational in patients if an R0 resection can be achieved. CONCLUSION: Surgical resection of colorectal liver metastases is the gold standard for oncological therapy whenever possible. The rational combination of non-curative surgical resection and local ablation should be considered in the context of a multimodal therapeutic strategy, particularly in patients with primarily resectable disease.

Stentgraft Implantation for the Treatment of Postoperative Hepatic Artery Pseudoaneurysm.

PURPOSE: Hepatic artery pseudoaneurysms are a rare but potentially life-threatening complication of major pancreaticobiliary surgery. We evaluated the safety and efficacy of endovascular stentgraft implantation for the management of such vascular lesions. MATERIALS AND METHODS: Between May 2013 and October 2015, ten patients with postoperative hepatic artery pseudoaneurysm, of which eight presented with active hemorrhage, were treated with endovascular stentgraft implantation. All patients had undergone major pancreatic or hepatic surgery before (pylorus-preserving pancreaticoduodenectomy, pancreatectomy, hemihepatectomy, extended hemihepatectomy). The pseudoaneurysms were diagnosed 13-202 days after surgery and were associated with postsurgical complications (e.g., leakage of pancreaticojejunal anastomosis). RESULTS: In 9/10 patients, the pseudoaneurysm was completely excluded via stentgraft implantation. In 1/10 patient, the pseudoaneurysm ruptured during the procedure and was successfully treated by immediate open surgery. In 1/10 patient, a second intervention was performed after 6 days because of rebleeding; this was successfully treated by implantation of a second overlapping stentgraft. Mean follow-up time is 51 days. None of the patients died due to stentgraft- or aneurysm-related complications. Further episodes of hemorrhage were not observed. In one patient, clinically asymptomatic complete occlusion of the stentgraft was discovered at follow-up imaging. CONCLUSION: Stentgraft implantation is a safe and effective technique to treat hepatic artery pseudoaneurysms related to major pancreatic or hepatic surgery, especially in the setting of acute hemorrhage.

Efficacy of magnetic thermoablation using SPIO in the treatment of osteoid osteoma in a bovine model compared to radiofrequency and microwave ablation.

PURPOSE: To evaluate heating efficacy of superparamagnetic iron oxide nanoparticles (SPIO) for electromagnetic ablation (EMA) of osteoid osteoma (OO) using an ex vivo model compared to radiofrequency ablation (RFA) and microwave ablation (MWA). METHODS: A model for OO using sliced bovine tibia and sliced muscle tissue was developed. A bone cavity filled with either a mixture of SPIO and agarose or pure agarose (control group) was established. EMA was performed using an experimental system, RFA and MWA using clinically approved systems, and the ablation protocols recommended by the vendor. For temperature measurements, fiberoptic temperature probes were inserted inside the cavity, on the outside of the periosteum, and at a 5 mm distance to the periosteum. RESULTS: Maximum temperatures with or without SPIO in the nidus were as follows: EMA: 79.9 ± 2.5/22.3 ± 0.7 °C; RFA: 95.1 ± 1.8/98.6 ± 0.9 °C; MWA: 85.1 ± 10.8/83.4 ± 9.62 °C. In RFA with or without SPIO significantly higher temperatures were achieved in the nidus compared to all other groups (p < 0.05). In MWA significantly higher temperatures were observed in the 5 mm distance to the periosteum compared to EMA and RFA with or without SPIO (p < 0.05). In MWA temperature decrease between nidus and the 5 mm distance to the periosteum was significantly lower than in RFA with or without SPIO (p < 0.0001). In MWA without SPIO temperature decrease was significantly lower than in the EMA group (p < 0.05). CONCLUSION: In the experimental setting, ablation of OO is safe and effective using EMA. It is less invasive than RFA and MWA, and it theoretically allows repeated treatments without repeated punctures. In comparison, the highest temperatures in the nidus are reached using RFA.

Carbon dioxide-contrasted computed tomography angiography: high pitch protocols and adapted injection parameters improve imaging quality.

PURPOSE: To systematically investigate the impact of image acquisition and contrast injection parameters for CO2-enhanced CT angiography (CTA) of the aorto-iliac and peripheral arteries in a pig model using commercially available equipment. The aim was to establish an imaging protocol that is ready for use in human subjects. MATERIALS AND METHODS: Three domestic swine underwent CO2-CTA with varying injection parameters: pitch (1.0, 3.0), injection pressure (0.7 bar, 1.0 bar, 1.3 bar) and scan delay (2 s, 4 s, 6 s). Objective (vessel diameter) and subjective (image quality) parameters and applied radiation doses were systematically evaluated. To ensure clinical applicability of the setting, only approved catheters/injectors and standard injection parameters were evaluated. RESULTS: The image quality scores were superior and the vessel diameter was larger with high pitch in comparison to standard pitch (diameters: 4.7 ± 2.0 mm vs. 3.6 ± 2.1 mm, p = 0.0040, scores: 2.6 ± 1.1 vs. 2.0 ± 1.1, p = 0.0038). High injection pressure (1.3 bar) improved the image quality as assessed by subjective and objective ratings (diameters: 3.6 ± 2.0 mm, 4.0 ± 2.1 mm and 4.6 ± 2.1 mm, for 0.7, 1.0 and 1.3 bar, p-values ≤ 0.0052, scores: 1.9 ± 1.1, 2.3 ± 1.1 and 2.7 ± 1.2, p-values ≤ 0.0017), the same was observed for a shorter injection delay (diameters: 3.5 ± 2.0 mm, 4.2 ± 2.1 mm and 4.8 ± 2.1 mm, for 6 s, 4 s, and 2 s, p ≤ 0.0022, scores: 1.9 ± 1.1, 2.3 ± 1.1 and 2.7 ± 1.1, p-values ≤ 0.0013). The dose length products were 239 ± 47 mGycm (high pitch) and 565 ± 63 mGycm (standard pitch, p-values < 0.0001). CONCLUSION: A higher pitch, shorter delay and higher injection pressure improve image quality in CO2-enhanced CTA. Since commercially available, clinically approved equipment was used. The protocol is now ready for use in human subjects.