Sphere-enhanced microwave ablation (sMWA) versus bland microwave ablation (bMWA): technical parameters, specific CT 3D rendering and histopathology.

PURPOSE: This study was designed to compare technical parameters during ablation as well as CT 3D rendering and histopathology of the ablation zone between sphere-enhanced microwave ablation (sMWA) and bland microwave ablation (bMWA). METHODS: In six sheep-livers, 18 microwave ablations were performed with identical system presets (power output: 80 W, ablation time: 120 s). In three sheep, transarterial embolisation (TAE) was performed immediately before microwave ablation using spheres (diameter: 40 ± 10 µm) (sMWA). In the other three sheep, microwave ablation was performed without spheres embolisation (bMWA). Contrast-enhanced CT, sacrifice, and liver harvest followed immediately after microwave ablation. Study goals included technical parameters during ablation (resulting power output, ablation time), geometry of the ablation zone applying specific CT 3D rendering with a software prototype (short axis of the ablation zone, volume of the largest aligned ablation sphere within the ablation zone), and histopathology (hematoxylin-eosin, Masson Goldner and TUNEL). RESULTS: Resulting power output/ablation times were 78.7 ± 1.0 W/120 ± 0.0 s for bMWA and 78.4 ± 1.0 W/120 ± 0.0 s for sMWA (n.s., respectively). Short axis/volume were 23.7 ± 3.7 mm/7.0 ± 2.4 cm(3) for bMWA and 29.1 ± 3.4 mm/11.5 ± 3.9 cm(3) for sMWA (P < 0.01, respectively). Histopathology confirmed the signs of coagulation necrosis as well as early and irreversible cell death for bMWA and sMWA. For sMWA, spheres were detected within, at the rim, and outside of the ablation zone without conspicuous features. CONCLUSIONS: Specific CT 3D rendering identifies a larger ablation zone for sMWA compared with bMWA. The histopathological signs and the detectable amount of cell death are comparable for both groups. When comparing sMWA with bMWA, TAE has no effect on the technical parameters during ablation.

CT-guided irreversible electroporation in an acute porcine liver model: effect of previous transarterial iodized oil tissue marking on technical parameters, 3D computed tomographic rendering of the electroporation zone, and histopathology.

PURPOSE: To evaluate the effect of previous transarterial iodized oil tissue marking (ITM) on technical parameters, three-dimensional (3D) computed tomographic (CT) rendering of the electroporation zone, and histopathology after CT-guided irreversible electroporation (IRE) in an acute porcine liver model as a potential strategy to improve IRE performance. METHODS: After Ethics Committee approval was obtained, in five landrace pigs, two IREs of the right and left liver (RL and LL) were performed under CT guidance with identical electroporation parameters. Before IRE, transarterial marking of the LL was performed with iodized oil. Nonenhanced and contrast-enhanced CT examinations followed. One hour after IRE, animals were killed and livers collected. Mean resulting voltage and amperage during IRE were assessed. For 3D CT rendering of the electroporation zone, parameters for size and shape were analyzed. Quantitative data were compared by the Mann-Whitney test. Histopathological differences were assessed. RESULTS: Mean resulting voltage and amperage were 2,545.3 ± 66.0 V and 26.1 ± 1.8 A for RL, and 2,537.3 ± 69.0 V and 27.7 ± 1.8 A for LL without significant differences. Short axis, volume, and sphericity index were 16.5 ± 4.4 mm, 8.6 ± 3.2 cm(3), and 1.7 ± 0.3 for RL, and 18.2 ± 3.4 mm, 9.8 ± 3.8 cm(3), and 1.7 ± 0.3 for LL without significant differences. For RL and LL, the electroporation zone consisted of severely widened hepatic sinusoids containing erythrocytes and showed homogeneous apoptosis. For LL, iodized oil could be detected in the center and at the rim of the electroporation zone. CONCLUSION: There is no adverse effect of previous ITM on technical parameters, 3D CT rendering of the electroporation zone, and histopathology after CT-guided IRE of the liver.

CT-guided bipolar and multipolar radiofrequency ablation (RF ablation) of renal cell carcinoma: specific technical aspects and clinical results.

PURPOSE: This study was designed to evaluate the clinical efficacy of CT-guided bipolar and multipolar radiofrequency ablation (RF ablation) of renal cell carcinoma (RCC) and to analyze specific technical aspects between both technologies. METHODS: We included 22 consecutive patients (3 women; age 74.2 ± 8.6 years) after 28 CT-guided bipolar or multipolar RF ablations of 28 RCCs (diameter 2.5 ± 0.8 cm). Procedures were performed with a commercially available RF system (Celon AG Olympus, Berlin, Germany). Technical aspects of RF ablation procedures (ablation mode [bipolar or multipolar], number of applicators and ablation cycles, overall ablation time and deployed energy, and technical success rate) were analyzed. Clinical results (local recurrence-free survival and local tumor control rate, renal function [glomerular filtration rate (GFR)]) and complication rates were evaluated. RESULTS: Bipolar RF ablation was performed in 12 procedures and multipolar RF ablation in 16 procedures (2 applicators in 14 procedures and 3 applicators in 2 procedures). One ablation cycle was performed in 15 procedures and two ablation cycles in 13 procedures. Overall ablation time and deployed energy were 35.0 ± 13.6 min and 43.7 ± 17.9 kJ. Technical success rate was 100 %. Major and minor complication rates were 4 and 14 %. At an imaging follow-up of 15.2 ± 8.8 months, local recurrence-free survival was 14.4 ± 8.8 months and local tumor control rate was 93 %. GFR did not deteriorate after RF ablation (50.8 ± 16.6 ml/min/1.73 m(2) before RF ablation vs. 47.2 ± 11.9 ml/min/1.73 m(2) after RF ablation; not significant). CONCLUSIONS: CT-guided bipolar and multipolar RF ablation of RCC has a high rate of clinical success and low complication rates. At short-term follow-up, clinical efficacy is high without deterioration of the renal function.

[Compatibility of family and profession. Survey of radiologists and medical technical personnel in clinics with different organizations]. / Vereinbarkeit von Familie und Beruf. Umfrage unter Radiologen und medizinisch-technischen Angestellten in Kliniken unterschiedlicher Ausrichtung.

PURPOSE: The compatibility of family and profession is especially difficult for employees in medical professions because of shift work and overtime. It seems that in the future women are going to represent the majority of medical professionals in Germany. Hence, with the forthcoming lack of physicians in Germany social aspects will also play a greater role in the choice of the place of employment. Therefore a statistical survey was made among employees on how they judge the compatibility of family and job and what they would like to improve. MATERIALS AND METHODS: From autumn 2009 until spring 2010 a total of 115 questionnaires were distributed to 8 different academic radiology departments. The anonymous questionnaire with partially open, partially graded questions and partially multiple answer questions was designed with the help of an expert for statistics and analytics and included questions about the employment and family situation, plans for the future, requested flexible working hours and childcare models, as well as ideas for improvement. Of the questionnaires 87 were analyzed with a specially designed access database using, for example descriptive statistics and histogram analyses. RESULTS: Of the interviewees 68% were female and 31% were male (1% not significant n.s.), 46% had children and 49% were childless (5% n.s.), 63% were medical doctors, 33% radiographers (3% other) and 82% worked full-time. Of the male respondents with children 42% indicated that their spouse was at home, 18% of female respondents with children indicated that their spouse was at home and only mothers worked part-time. Of the male respondents 73% would like to take parental leave, 44% of all respondents (70% of the male respondents and 34% of the female respondents) agreed that radiology is more compatible with family than other medical disciplines and 87% would like to have a childcare possibility in close proximity to the working place. DISCUSSION/CONCLUSIONS: In most of the families the classic role model prevails, although women are well-educated and men also set a high value on the compatibility of family and profession and would like to take parental leave and work flexible working hours. This is a chance especially for radiology.

[Transarterial ablation of hepatocellular carcinoma. Status and developments]. / Transvaskuläre Ablation des hepatozellulären Karzinoms. Ist Chemotherapie alles?

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and represents the main cause of death among European patients with liver cirrhosis. Only 30-40% of patients diagnosed with HCC are candidates for curative treatment options (e.g. surgical resection, liver transplantation or ablation). The remaining majority of patients must undergo local regional and palliative therapies. Transvascular ablation of HCC takes advantage of the fact that the hypervascularized HCC receives most of its blood supply from the hepatic artery. In this context transvascular ablation describes different therapy regimens which can be assigned to four groups: cTACE (conventional transarterial chemoembolization), bland embolization (transarterial embolization TAE), DEB-TACE (TACE with drug-eluting beads, DEB) and SIRT (selective internal radiation therapy, radioembolization). Conventional TACE is the most common type of transvascular ablation and represents a combination of intra-arterial chemotherapy and embolization with occlusion of the arterial blood supply. However, there is no standardized regimen with respect to the chemotherapeutic drug, the embolic agent, the usage of lipiodol and the interval between the TACE procedures. Even the exact course of a cTACE procedure (order of chemotherapy or embolization) is not standardized. It remains unclear whether or not intra-arterial chemotherapy is definitely required as bland embolization using very small, tightly calibrated spherical particles (without intra-arterial administration of a chemotherapeutic drug) shows tumor necrosis comparable to cTACE. For DEB-TACE microparticles loaded with a chemotherapeutic drug combine the advantages of cTACE and bland embolization. Thereby, a continuing chemotherapeutic effect within the tumor might cause a further increase in intratumoral cytotoxicity and at the same time a decrease in systemic toxicity.

Super-micro-bland particle embolization combined with RF-ablation: angiographic, macroscopic and microscopic features in porcine kidneys.

PURPOSE: To describe angiographic, macroscopic and microscopic features of super-micro-bland particle embolization in combination with RF-ablation in kidneys. Thereby, a special focus was given on the impact of the sequence of the different procedural steps. MATERIALS AND METHODS: In ten pigs, super-micro-bland particle embolization combined with RF-ablation was carried out. Super-micro-bland embolization was performed with spherical particles of very small size and tight calibration (40 ± 10 µm). In the left kidneys, RF-ablations were performed before embolization (I). In the right kidneys, RF-ablations were performed after embolization (II). The animals were killed three hours after the procedures. Angiographic (e.g. vessel architecture), macroscopic (e.g. long and short axes of the RF-ablations) and microscopic (e.g. particle distribution) study goals were defined. RESULTS: Angiography detected almost no vessels in the center of the RF-ablations in I. In II, angiography could not define the RF-ablations. Macroscopy detected significantly larger long and short axes of the RF-ablations in II compared to I (52.2 ± 3.2 mm vs. 45.3 ± 6.9 mm [P<0.05] and 25.1 ± 3.5mm vs. 20.0 ± 1.9 mm [P<0.01], respectively). Microscopy detected irregular particle distribution at the rim of the RF-ablations in I. In II, microscopy detected homogeneous particle distribution at the rim of the RF-ablations. Microscopy detected no particles in the center of the RF-ablations in I and II. CONCLUSION: The sequence of the different procedural steps of super-micro-bland particle embolization combined with RF-ablation impacts angiographic, macroscopic and microscopic features in kidneys in the acute setting.

Dual-energy CT-cholangiography in potential donors for living-related liver transplantation: improved biliary visualization by intravenous morphine co-medication.

PURPOSE: To prospectively evaluate whether intravenous morphine co-medication improves bile duct visualization of dual-energy CT-cholangiography. MATERIALS AND METHODS: Forty potential donors for living-related liver transplantation underwent CT-cholangiography with infusion of a hepatobiliary contrast agent over 40 min. Twenty minutes after the beginning of the contrast agent infusion, either normal saline (n=20 patients; control group [CG]) or morphine sulfate (n=20 patients; morphine group [MG]) was injected. Forty-five minutes after initiation of the contrast agent, a dual-energy CT acquisition of the liver was performed. Applying dual-energy post-processing, pure iodine images were generated. Primary study goals were determination of bile duct diameters and visualization scores (on a scale of 0 to 3: 0--not visualized; 3--excellent visualization). RESULTS: Bile duct visualization scores for second-order and third-order branch ducts were significantly higher in the MG compared to the CG (2.9±0.1 versus 2.6±0.2 [P<0.001] and 2.7±0.3 versus 2.1±0.6 [P<0.01], respectively). Bile duct diameters for the common duct and main ducts were significantly higher in the MG compared to the CG (5.9±1.3 mm versus 4.9±1.3 mm [P<0.05] and 3.7±1.3 mm versus 2.6±0.5 mm [P<0.01], respectively). CONCLUSION: Intravenous morphine co-medication significantly improved biliary visualization on dual-energy CT-cholangiography in potential donors for living-related liver transplantation.

Microwave ablation of porcine kidneys in vivo: effect of two different ablation modes ("temperature control" and "power control") on procedural outcome.

PURPOSE: This study was designed to analyze the effect of two different ablation modes ("temperature control" and "power control") of a microwave system on procedural outcome in porcine kidneys in vivo. METHODS: A commercially available microwave system (Avecure Microwave Generator; MedWaves, San Diego, CA) was used. The system offers the possibility to ablate with two different ablation modes: temperature control and power control. Thirty-two microwave ablations were performed in 16 kidneys of 8 pigs. In each animal, one kidney was ablated twice by applying temperature control (ablation duration set point at 60 s, ablation temperature set point at 96°C, automatic power set point; group I). The other kidney was ablated twice by applying power control (ablation duration set point at 60 s, ablation temperature set point at 96°C, ablation power set point at 24 W; group II). Procedural outcome was analyzed: (1) technical success (e.g., system failures, duration of the ablation cycle), and (2) ablation geometry (e.g., long axis diameter, short axis diameter, and circularity). RESULTS: System failures occurred in 0% in group I and 13% in group II. Duration of the ablation cycle was 60±0 s in group I and 102±21 s in group II. Long axis diameter was 20.3±4.6 mm in group I and 19.8±3.5 mm in group II (not significant (NS)). Short axis diameter was 10.3±2 mm in group I and 10.5±2.4 mm in group II (NS). Circularity was 0.5±0.1 in group I and 0.5±0.1 in group II (NS). CONCLUSIONS: Microwave ablations performed with temperature control showed fewer system failures and were finished faster. Both ablation modes demonstrated no significant differences with respect to ablation geometry.

[Compatibility of family and medical profession]. / Vereinbarkeit von Familie und ärztlichem Beruf.

The compatibility of family and profession is especially difficult for employees in medical professions because of shift work and overtime. It seems that in the future women are going to represent the majority of medical professionals. Hence, with the manifest lack of physicians social aspects will also play a bigger role in the choice of the place of employment. In most families the classic role model prevails although women are well educated and men also set a high value on the compatibility of family and profession and would like to take parental leave and work in flexible working hours. This represents a chance, especially for radiology.

Successful thrombolysis and spasmolysis of acute leg ischemia after accidental intra-arterial injection of dissolved flunitrazepam tablets.

A 37-year-old man with known intravenous drug abuse presented in the surgical ambulatory care unit with acute leg ischemia after accidental intra-arterial injection of dissolved flunitrazepam tablets into the right femoral artery. A combination of anticoagulation, vasodilatation, and local selective and superselective thrombolysis with urokinase was performed to salvage the leg. As a result of the severe ischemia-induced pain, the patient had to be monitored over the complete therapy period on the intensive care unit with permanent administration of intravenous fluid and analgetics. We describe the presenting symptoms and the interventional technique, and we discuss the recent literature regarding the management of accidental intra-arterial injection of dissolved flunitrazepam tablets.

Renal artery embolization combined with radiofrequency ablation in a porcine kidney model: effect of small and narrowly calibrated microparticles as embolization material on coagulation diameter, volume, and shape.

The purpose of this study was to evaluate the effect of renal artery embolization with small and narrowly calibrated microparticles on the coagulation diameter, volume, and shape of radiofrequency ablations (RFAs) in porcine kidneys. Forty-eight RFAs were performed in 24 kidneys of 12 pigs. In 6 animals, bilateral renal artery embolization was performed with small and narrowly calibrated microparticles. Upper and lower kidney poles were ablated with identical system parameters. Applying three-dimensional segmentation software, RFAs were segmented on registered 2 mm-thin macroscopic slices. Length, depth, width, volume_segmented, and volume_calculated were determined to describe the size of the RFAs. To evaluate the shape of the RFAs, depth-to-width ratio (perfect symmetry-to-lesion length was indicated by a ratio of 1), sphericity ratio (perfect sphere was indicated by a sphericity ratio of 1), eccentricity (perfect sphere was indicated by an eccentricity of 0), and circularity (perfect circle was indicated by a circularity of 1) were determined. Embolized compared with nonembolized RFAs showed significantly greater depth (23.4 ± 3.6 vs. 17.2 ± 1.8 mm; p < 0.001) and width (20.1 ± 2.9 vs. 12.6 ± 3.7 mm; p < 0.001); significantly larger volume_segmented (8.6 ± 3.2 vs. 3.0 ± 0.7 ml; p < 0.001) and volume_calculated (8.4 ± 3.0 ml vs. 3.3 ± 1.1 ml; p < 0.001); significantly lower depth-to-width (1.17 ± 0.10 vs. 1.48 ± 0.44; p < 0.05), sphericity (1.55 ± 0.44 vs. 1.96 ± 0.43; p < 0.01), and eccentricity (0.84 ± 0.61 vs. 1.73 ± 0.91; p < 0.01) ratios; and significantly greater circularity (0.62 ± 0.14 vs. 0.45 ± 0.16; p < 0.01). Renal artery embolization with small and narrowly calibrated microparticles affected the coagulation diameter, volume, and shape of RFAs in porcine kidneys. Embolized RFAs were significantly larger and more spherical compared with nonembolized RFAs.

Effect of intravenous morphine comedication on bile duct visualization, diameter and volume applying intravenous CT cholangiography in a porcine liver model.

BACKGROUND/AIMS: To determine whether intravenous morphine comedication improves bile duct visualization, diameter and/or volume applying intravenous CT cholangiography in a porcine liver model. METHODS: 12 Landrace pigs underwent intravenous CT cholangiography. Eight minutes after initiation of the contrast material infusion, either morphine sulfate (n = 6 animals) or normal saline (n = 6 animals) was administered. Eighteen consecutive CT scans of the liver were acquired with 2-min intervals starting with initiation of the contrast material infusion. Maximum bile duct visualization scores, diameters and volumes and time to maximum bile duct visualization scores, diameters and volumes were determined. RESULTS: Maximum bile duct visualization scores, diameters and volumes and time to maximum bile duct visualization scores, diameters and volumes were not significantly different when the morphine group was compared to the normal saline group. Maximum bile duct visualization scores ranged between 4.00 ± 0.00 and 2.83 ± 1.47. Maximum bile duct diameters ranged between 6.77 ± 0.40 and 2.10 ± 1.35 mm. Maximum bile duct volume was 16.41 ± 7.33 ml in the morphine group and 16.79 ± 5.65 ml in the normal saline group. CONCLUSION: Intravenous morphine comedication failed to improve bile duct visualization and to increase bile duct diameter and volume applying CT cholangiography.

Patients with life-threatening arterial renal hemorrhage: CT angiography and catheter angiography with subsequent superselective embolization.

The purpose of this study was to evaluate the technical and clinical success of superselective embolization in patients with life-threatening arterial renal hemorrhage undergoing preinterventional CT angiography. Forty-three patients with clinical signs of life-threatening arterial renal hemorrhage underwent CT angiography and catheter angiography. Superselective embolization was indicated in the case of a positive catheter angiography. Primary study goals were technical and clinical success of superselective embolization. Secondary study goals were CT angiographic and catheter angiographic image findings and clinical follow-up. The mean time interval between CT angiography and catheter angiography was 8.3 +/- 10.3 h (range, 0.2-34.1 h). Arterial renal hemorrhage was identified with CT angiography in 42 of 43 patients (98%) and catheter angiography in 39 of 43 patients (91%) (overview angiography in 4 of 43 patients [9%], selective angiography in 16 of 43 patients [37%], and superselective angiography in 39 of 43 patients [91%]). Superselective embolization was performed in 39 of 43 patients (91%) and technically successful in 37 of 39 patients (95%). Therefore, coil embolization was performed in 13 of 37 patients (35%), liquid embolization in 9 of 37 patients (24%), particulate embolization in 1 of 37 patients (3%), and a combination in 14 of 37 patients (38%). Clinical failure occurred in 8 of 39 patients (21%) and procedure-related complications in 2 of 39 patients (5%). The 30-day mortality rate was 3%. Hemoglobin decreased significantly prior to intervention (P < 0.001) and increased significantly after intervention (P < 0.005). In conclusion, superselective embolization is effective, reliable, and safe in patients with life-threatening arterial renal hemorrhage. In contrast to overview and selective angiography, only superselective angiography allows reliable detection of arterial renal hemorrhage. Preinterventional CT angiography is excellent for detection and localization of arterial renal hemorrhage and appropriate for guidance of the embolization procedure.