[Postmortem imaging procedures : Experiences and perspectives]. / Postmortale bildgebende Verfahren : Erfahrungen und Ausblicke.

Autopsies are of key importance for the understanding of the anatomy, pathophysiology and pathomorphology. In forensic medicine, the virtual autopsy is a standard instrument in autopsy practice. The advantage of postmortem imaging is the generation of a three-dimensional pre-autopsy snapshot of the body from head to toe with excellent visualization of skeletal pathologies and air inclusions. When angiography is performed, pathologies of the cardiovascular system can additionally be evaluated. The shortcomings of postmortem imaging are the low soft tissue contrast with CT imaging, the lack of haptic, olfactory and color impressions. Another limitation is the access to CT and particularly to magnetic resonance imaging (MRI) facilities and the necessary experience with the peculiarities of postmortem imaging. To date, postmortem imaging can supplement but not replace the traditional autopsy. Nevertheless, postmortem imaging adds valuable technical capabilities to the traditional autopsy. The ability to achieve valid results for the cause of death and additional diagnoses must be evaluated systematically for postmortem imaging, in particular in addition to CT or MR guided biopsies. This article gives an overview of the current state of the technology and encourages its development for application in pathology departments.

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.

[Cryoablation - back again?]. / Kryoablation - wieder da?

CLINICAL ISSUE: Primary and secondary liver tumors often limit patient outcome and only a minority of patients are eligible for potential curative surgery. Minimally invasive treatments, such as radiofrequency ablation (RFA), microwave ablation (MWA) and cryoablation are alternative treatment options in a curative and palliative setting. One major limitation of RFA and MWA is the limited size of tumor ablation. Furthermore during the procedure the ablation size can only be roughly estimated using RFA and MWA. STANDARD TREATMENT: RFA is the standard modality of minimally invasive tumor therapy. In comparison cryoablation is rarely used despite its advantages. TREATMENT INNOVATIONS: Argon-helium-based cryoablation systems of the newest generation combine the advantage of small diameter applicators comparable with those of RFA and MWA systems with intrinsic advantages. ACHIEVEMENTS: Cryoablation is a minimally invasive treatment option with advantages, such as virtually unlimited ablation size, real-time visualization using computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound and intrinsic analgesic effects. On the other hand it is not very time-efficient in comparison to MWA. Especially in liver metastases RFA is the preferred treatment option. PRACTICAL RECOMMENDATIONS: Cryoablation is a fascinating treatment option in minimally invasive tumor treatment. It demonstrates good results in hepatocellular carcinoma within the Milan criteria and T1a renal cell carcinoma. Furthermore it is a well-established treatment modality for palliative pain management in bone tumors.

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.

[Unilateral tongue atrophy and articulation difficulties]. / Einseitige Zungenatrophie und Artikulationsschwierigkeiten.

A 24-year-old female complained of difficulty articulating and chewing of 2 more than weeks' standing. She reported that her tongue felt "heavy and inert". Clinically, right-sided atrophy of the tongue and deflection of the tongue to the right were observed. Tone audiogram demonstrated normal hearing on both sides and tympanometry was also normal. On CT, a bone-destroying process was seen in the area of the right lateral skull base, which reached as far as the internal carotid artery. MRI demonstrated atrophy of the right tongue musculature with fatty degeneration, as well as an oval, smoothly edged lesion which showed marked contrast-medium uptake with a "salt and pepper" configuration in the region of the right jugular foramen. The diagnosis was hypoglossal paresis due to ipsilateral jugular paraganglioma (Fisch classification C1). Following embolization of the feeding vessels of the paraganglioma, the tumor was completely resected, including the hypoglossal nerve which ran through the tumor. Postoperative dysfunction of the vagus and facial nerves became unsymptomatic with time as a result of logopedic therapy.

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.

Toward Transpulmonary Chemoembolization with Degradable Starch Microspheres: Systematic Analysis of Local and Systemic Effects in a Porcine Model.

PURPOSE: To investigate local and systemic effects of transpulmonary chemoembolization (TPCE) with degradable starch microspheres (DSM) and doxorubicin. The long-term goal is to establish DSM-TPCE as a treatment option for pulmonary malignancies. MATERIALS AND METHODS: Nine pigs underwent TPCE of either the right or left lower lobe pulmonary artery (LLPA) and bland embolization (TPE) of the contralateral LLPA. Before the procedures, macroaggregated albumin (MAA) particles were injected into both LLPAs, to exclude systemic shunting. Pulmonary arterial pressure, heart rate and oxygenation were recorded immediately before and at 1, 3, 5 and 10 min after treatment. To investigate possible nontarget embolization, animals underwent cerebral MRI (cMRI). We killed the animals after a contrast-enhanced chest computed tomography (CT) and performed a pathologic examination at 12 h (3), 24 h (3) and 72 h (3) after treatment. RESULTS: All experiments were technically successful. Mean injected DSM dose until stasis was similar in TPCE and TPE (4.3 ± 1.4 vs. 4.0 ± 1.4 mL). Pulmonary arterial pressure increased significantly 3 min after treatment (TPE: 17 ± 5 vs. 27 ± 7 mmHg; TPCE: 22 ± 6 vs. 36 ± 8 mmHg). No significant changes in heart rate or peripheral oxygenation levels occurred. We observed no evidence of structural lung damage or permanent perfusion disruption on CT. MAA test injection and cMRI revealed no shunting or nontarget embolization. The pathologic assessment revealed nonspecific local inflammation of the lung parenchyma. CONCLUSION: In this large-animal model, TPCE and TPE appear feasible and safe. We observed a mild increase in pulmonary arterial pressure. Nontarget embolization did not occur. TPCE, as well as TPE, did not cause structural damage to the normal lung parenchyma.

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.

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.

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.

Silicon carbide-enhanced microwave ablation in an ex-vivo bovine liver model - effects on heat distribution and ablation volume.

PURPOSE: Evaluation of the maximum temperatures and ablation volumes in microwave ablation (MWA) after injection of different concentrations of silicon carbide (SiC) particles in an ex-vivo bovine liver model. MATERIALS AND METHODS: 15 ml of different concentrations of SiC particles (20 vol% SiC; 50 vol% SiC) mixed with 2 % gelatin were injected into an ex-vivo bovine liver. As a reference group, 2 % gelatin without SiC was injected. MWA was performed using a clinical MWA system with different generator settings (10 - 45 W/10 minutes). The temperature was measured at a distance of 5 mm and 10 mm from the applicator. Afterwards the liver tissue was sliced along the short and long axis, the ablation zones were measured on the x, y and z-axis and the ablation volume was calculated. All experiments were performed 5 times (total: 40 experiments). RESULTS: The average maximum temperatures measured at a generator setting of 45 W at a distance of 5 mm from the applicator were 103.4 ± 4.6 °C (20 vol% SiC), 103.3 ± 6.5 °C (50 vol% SiC) and 96.0 ± 4.2 °C in the control group (0 vol% SiC). At 45 W, injection of 20 vol% SIC caused a significantly higher maximum temperature than that achieved in the control group (p = 0.016). No significant temperature increase compared to the control group could be measured using 50 vol% SiC. The mean ablation volumes at 45 W and 20 vol% SiC and 50 vol% SiC were significantly larger (172.7 ± 31.5 ml and 171.0 ± 34.7 ml, respectively) than those achieved in the control group (111.2 ± 23.8 ml) (p = 0.027 and p = 0.045). CONCLUSION: In an ex-vivo bovine liver model, the SiC particles demonstrated an enhancing effect of MWA with respect to maximum temperatures and ablation volume. Therefore, SiC is a promising candidate for enhancing MWA in vivo.

Silicon carbide as a heat-enhancing agent in microwave ablation: in vitro experiments.

PURPOSE: Silicon carbide (SiC) is an inert compound material with excellent microwave absorption and heat-conducting properties. The aim of our study was to investigate the heat-enhancing effects of SiC in microwave ablation in an in vitro setting. MATERIALS AND METHODS: Different concentrations of SiC powder were mixed with 2% gelatin, producing a 20-ml mixture that was then heated with a clinical microwave ablation system (5 min/45 W). Temperature was measured continuously fiberoptically. Additional heating properties were assessed for the most heatable concentrations at different energy settings (10, 20, and 30 W). As reference, 2% gelatin without SiC was heated. Statistical evaluation by analysis of variance with post hoc Student-Newman-Keuls testing was performed. RESULTS: For the different SiC concentrations, maximum temperatures measured were 45.7 ± 1.2°C (0% SiC, control), 50.4 ± 3.6°C (2% SiC), 60.8 ± 1.8°C (10% SiC), 74.9 ± 2.6°C (20% SiC), and 83.4 ± 2.5°C (50% SiC). Differences between all data points were significant (P < 0.05). Maximum temperatures that used 20% SiC were 36.3 ± 2.76°C (10 W), 48.7 ± 4.18°C (20 W), and 50.6 ± 0.68°C (30 W). The use of 50% SiC maximum temperatures resulted in values of 46.2 ± 2.52°C (10 W), 70.1 ± 0.64°C (20 W), and 83.0 ± 4.69°C (30 W). With 20% SiC and 50% SiC mixtures, the 10 W maximum temperatures were significantly lower than at all other power levels, and maximum temperatures with 20 and 30 W were significantly lower when compared with 45 W (P < 0.05). CONCLUSIONS: SiC is a nontoxic, highly effective substance for enhancing microwave-induced heating with a microwave ablation system in vitro. These data suggest its usefulness for enhancement of ablative effects in percutaneous tumor therapy. Further investigations need to be performed to evaluate the ex vivo and in vivo ablation effects and the possible methods for administration of SiC particles.

[In vitro experiments on fluid-modulated microwave ablation]. / In-vitro-Experimente zur flüssigkeitsmodulierten Mikrowellenablation.

PURPOSE: Evaluation of the enhancing or protecting effects of different fluids during microwave ablation (MWA). MATERIALS AND METHODS: 3 samples of 17 different fluids (each 20 ml) were heated using MWA at power levels of 10, 20, 30, 40 and 45 watts. Energy was applied until the temperature reached 80 degrees C or the duration of heating exceeded 10 minutes. The cooling-down process was then observed until the temperature reached 30 degrees C. RESULTS: Gastrografin needed the shortest time to be heated up to 80 degrees C (370 sec), followed by Magnograf (410 sec) and HES 10 % (420 sec). The least heatable fluids were Lipiodol (10 min -54.5 +/- 2.43 degrees C), distilled water (10 min -56 +/- 2.42 degrees C) and Glucose 5 % solution (10 min -56.6 +/- 1.69 degrees C). Fluids which could not be heated well, such as distilled water, Lipiodol or Glucose 5 % solution, had a small slope of the temperature curve as a function of the power level used (m = 0.60 - 0.73), whereas fluids which could be heated well, such as Gastrografin, Magnograf and HES 10 %, had a much steeper slope of the temperature curve as a function of the power level (m = 0.99 - 1.20). With respect to the maximum temperature, the above mentioned groups differed significantly (p < 0.05). The temperature slope correlated strongly with maximum temperatures reached (Pearson correlation coefficient: 0.97). CONCLUSION: By additionally administering a carefully chosen fluid, enhancing or protecting effects during microwave ablation can be observed. Especially Gastrografin, Magnograf and HES 10 % can be used to enhance ablation effects, whereas protective effects can be observed particularly when using Lipiodol, distilled water and Glucose 5 %-solution.