Contrast enhanced ultrasound (CEUS) with parametric imaging and time intensity curve analysis (TIC) for evaluation of the success of prostate arterial embolization (PAE) in cases of prostate hyperplasia.

AIM: To evaluate the use of dynamic contrast enhanced ultrasound (CEUS) with parametric color-coded imaging and time intensity curve analysis (TIC) for planning and follow-up after prostate arterial embolization (PAE). MATERIAL/METHOD: Before and after selective iliacal embolization by PAE with a follow up of 6 months 18 male patients (43-78 years, mean 63±3.5 years) with histopathological proven benign prostate hyperplasia were examined by one experienced examiner. A multifrequency high resolution probe (1-6 MHz) was used for transabdominal ultrasound and CEUS with bolus injections of 2.4 ml sulphur-hexafluoride microbubbles. Independent evaluation of color-coded parametric imaging before and after PAE by in PACS stored DICOM loops from arterial phase (10-15 s) up to 1min were performed. Criteria for successful treatment were reduction of early arterial enhancement by changes of time to peak (TTP) and area under the curve (AUC) by measurements in 8 regions of interest (ROI) of 5 mm in diameter at the margin and in the center and changes from hyperenhancement in parametric imaging (perfusion evaluation of arterial enhancement over 15 s) from red and yellow to blue and green by partial infarctions. Reference imaging method was the contrast high resolution 3 tesla magnetic resonance tomography (MRI) using 3D vibe sequences before and after PAE and for the follow up after 3 and 6 months. RESULTS: PAE was technically and clinically successful in all 18 patients with less clinical symptoms and reduction of the gland volume. In all cases color-coded CEUS parametric imaging was able to evaluate partial infarction after embolization with changes from red and yellow to green and blue colors in the embolization areas. Relevant changes could be evaluated for TIC-analysis of CEUS with reduced arterial enhancement in the arterial phase and prolonged enhancement of up to 1 min with significant changes (p = 0.0024). The area under the curve (AUC) decreased from 676±255.04 rU (160 rU-1049 rU) before PAE to 370.43±255.19 rU (45 rU-858 rU) after PAE. Time to peak (TTP) did not change significantly (p = 0.6877); TTP before PAE was 25.82±9.04 s (12.3 s-42.5 s) and after PAE 24.43±9.10 s (12-39 s). Prostate volume decreased significantly (p = 0.0045) from 86.93±34.98 ml (30-139 ml) before PAE to 50.57±26.26 ml (19-117 ml) after PAE. There were no major complications and, in most cases (14/18) a volume reduction of the benign prostate hyperplasia occurred. CONCLUSION: Performed by an experienced examiner CEUS with parametric imaging and TIC-analysis is highly useful to further establish prostatic artery embolization (PAE) as a successful minimal invasive treatment of benign prostatic hyperplasia.

Evaluation of dynamic effects of therapy-induced changes in microcirculation after percutaneous treatment of vascular malformations using contrast-enhanced ultrasound (CEUS) and time intensity curve (TIC) analyses.

The aim of this follow-up study was to demonstrate the effect of percutaneous interventional treatment on local microcirculation of peripheral vascular malformations using CEUS and TIC analysis. MATERIAL AND METHODS: Retrospective analysis of 197 patients (136 female; 61 male; 3-86 years) with 135 venous (VM), 39 arterio-venous (AVM), 8 lymphatic and 15 veno-lymphatic peripheral vascular malformations before and after the first percutaneous treatment.CEUS was performed after i.v. injection of 1-2.4 ml of sulfur hexafluoride microbubbles (SonoVue®) using a 6-9 MHz linear probe. Digitally stored cine loops (starting in the early arterial phase for 60 sec) were read by independent readers in consensus. Regions of interest (ROI) were defined in the center and at the margins of the malformation, as well as in the healthy surrounding tissue. TIC analyses with Time to Peak (TTP) and Area under the Curve (AUC) were calculated using integrated perfusion software. RESULTS: After the treatment there was a significant decrease for median AUC in VM in the center from 297.8 (14.5-2167.6) rU down to 243.3 (0.1-1678.8) rU (p = 0.043) and in the surrounding tissue down to 107.7 (20.2-660.2) rU (p = 0.018). For the other malformations AUC decreased in the center and the margins as well. TTP rose, however these changes did not reach the level of significance. CONCLUSION: Analyzing the capillary microcirculation TICs offer a possibility of monitoring therapy-induced capillary changes of vascular malformations.

Reduced microperfusion due to portal vein thrombosis: Impact on the outcome of percutaneous thermal tumor ablation.

PURPOSE: To determine the influence of pre-interventionally existing portal vein thrombosis on the ablation success of percutaneous tumor ablation of HCC. MATERIALS AND METHODS: 15 patients with HCC and pre-existing portal vein thrombosis underwent thermal tumor ablation. We retrospectively analyzed the pre- and post-interventionally performed CT and MRI scans in terms of technical success as well as the complication rate. The portal vein thrombosis was classified into segmental, lobar and central thrombus. RESULTS: In 13/15 cases (87%) complete ablation with no evidence of residual tumor tissue was seen 6 weeks after the procedure in contrast-enhanced MRI scans and contrast-enhanced ultrasound (CEUS). No major and 2 minor complications were observed after the ablation procedure. CONCLUSION: Reduced perfusion due to pre-interventionally existing portal vein thrombosis has no significant impact on the ablation success or the complication rate.

Effect of irreversible electroporation of prostate cancer on microcirculation: Imaging findings in contrast-enhanced T1-weighted 3D MRI.

OBJECTIVES: Irreversible electroporation (IRE) is a novel focal ablation technique applicable for treatment of prostate cancer (PCa). We aim to evaluate imaging findings of T1-weighted contrast-enhanced MRI after percutaneous IRE of low-risk PCa. METHODS: A total of 13 male patients underwent IRE of focal low-risk PCa and were included in this analysis. Prostate IRE was conducted using 2-4 electrodes being placed under CT-fluoroscopy guidance. Dynamic contrast-enhanced 3D isotropic fat-saturated T1-weighted MRI (DCE-MRI) was performed 24-72 hours before and 24-72 hours after ablation. RESULTS: Ablated prostate was either homogeneously (8/13 [62%]) or heterogeneously (5/13 [38%]) hypo attenuating. Peripheral contrast enhancement manifesting as a hyper attenuating margin was observed during the arterial (60 sec) (3/13 [23%]) and venous (240 sec) (10/13 [77%]) phase. The ablation defect showed a sharp (8/13 [62%]) or blurry (5/13 [38%]) margin. CONCLUSIONS: The results show a venous peripheral rim enhancement in most of the cases, indicating reactive hyperaemia. The heterogeneous appearance of the defect zone in some cases may be secondary to sustained vascularization.

Comparison of computed tomography (CT) and contrast-enhanced ultrasound (CEUS) for the quantitative evaluation of an ablation defect following radiofrequency ablation of malignant liver lesions.

OBJECTIVE: To compare contrast-enhanced computed tomography (CT) and contrast-enhanced ultrasound (CEUS) for the quantitative evaluation of an ablation defect following radiofrequency ablation of malignant liver lesions in a prospective study. MATERIALS AND METHODS: 22 radiofrequency ablations of malignant liver tumors were performed. The ablation defects were then measured and evaluated by two independent examiners via contrast-enhanced computed tomography (CT) and contrast-enhanced ultrasound (CEUS) using a 1-5 MHz multifrequency convex ultrasound transducer (LOGIQ E9, GE) with respect to the short-axis diameter, the long-axis diameter, and the area. RESULTS: Quantitative evaluation of ablation defects is possible with both contrast-enhanced CT and CEUS. The average long-axis diameter was 47.1 mm (±11.08;±23,5%) on CEUS and 56.48 mm (±14.14;±25,0%) on CT; the short-axis diameter was 39.72 mm (±11.14;±28,05%) on CEUS and 40.27 mm (±10.50;±26,07%) on CT; the area was 1439.82 mm2 (±678.57;±47,13%) on CEUS and 2392.68 mm2 (1147.67;±48,0%) on CT. On average, ablation defects are assessed to be larger on CT than on CEUS. A significant correlation between the modalities could not be achieved for all measurement axes. CONCLUSION: CEUS can be used for the postinterventional detection and evaluation of ablation defects. However, these are always assessed to be larger on contrast-enhanced CT than CEUS.

Low Tube Voltage Liver MDCT with Sinogram-Affirmed Iterative Reconstructions for the Detection of Hepatocellular Carcinoma.

Aim of this study was to compare low tube voltage computed tomography (80 kV) of the liver using iterative image reconstruction (SAFIRE) with standard computed tomography (120 kV) using filtered back-projection (FBP) for the detection of hepatocellular carcinoma (HCC). 46 patients (43 men) with 93 HCC confirmed by 3 T MRI with Gd-EOB-DPTA, in inconclusive cases combined with contrast-enhanced ultrasound, underwent dual-energy CT. The raw data of the 80 kV tube was reconstructed using the iterative reconstruction algorithm SAFIRE with two strengths (I3 and I5). The virtual 120 kV image data set was reconstructed using FBP. The CT images were reviewed to determine the lesion-to-liver contrast (LLC), the lesion contrast-to-noise ratio (CNR) and the sensitivity. The LLC (57.1/54.3 [I3/I5] vs. 34.9 [FBP]; p ≤ 0.01), CNR (3.67/4.45 [I3/I5] vs. 2.48 [FBP]; p < 0.01) and sensitivity (91.4%/88.2% [I3/I5] vs. 72.0% [FBP]; p ≤ 0.01) were significantly higher in the low-voltage protocol using SAFIRE. Therefore, low tube voltage CT using SAFIRE results in an increased lesion-to-liver contrast as well as an improved lesion contrast-to-noise ratio compared to FBP at 120 kV which results in a higher sensitivity for the detection of HCC.

Percutaneous Irreversible Electroporation: Long-term survival analysis of 71 patients with inoperable malignant hepatic tumors.

Aim of this retrospective analysis was to evaluate the survival times after percutaneous irreversible electroporation (IRE) in inoperable liver tumors not amenable to thermal ablation. 71 patients (14 females, 57 males, median age 63.5 ± 10.8 years) with 103 liver tumors were treated in 83 interventions using IRE (NanoKnife® system). The median tumor short-axis diameter was 1.9 cm (minimum 0.4 cm, maximum 4.5 cm). 35 patients had primary liver tumors and 36 patients had liver metastases. The Kaplan-Meier method was employed to calculate the survival rates, and the different groups were compared using multivariate log-rank and Wilcoxon tests. The overall median survival time was 26.3 months; the median survival of patients with primary land secondary liver cancer did not significantly differ (26.8 vs. 19.9 months; p = 0.41). Patients with a tumor diameter >3 cm (p < 0.001) or more than 2 lesions (p < 0.005) died significantly earlier than patients with smaller or fewer tumors. Patients with hepatocellular carcinoma and Child-Pugh class B or C cirrhosis died significantly earlier than patients with Child-Pugh class A (p < 0.05). Patients with very early stage HCC survived significantly longer than patients with early stage HCC with a median survival of 22.3 vs. 13.7 months (p < 0.05).

Evaluation of a robotic system for irreversible electroporation (IRE) of malignant liver tumors: initial results.

OBJECTIVE: Comparison of conventional CT-guided manual irreversible electroporation (IRE) of malignant liver tumors and a robot-assisted approach regarding procedural accuracy, intervention time, dose, complications, and treatment success. METHODS: A retrospective single-center analysis of 40 cases of irreversible electroporation of malignant liver tumors in 35 patients (6 females, 29 males, average age 60.3 years). Nineteen of these ablation procedures were performed manually and 21 with robotic assistance. A follow-up (ultrasound, CT, and MRI) was performed after 6 weeks in all patients. RESULTS: The time from the planning CT scan to the start of the ablation as well as the dose-length product were significantly lower under robotic assistance (63.5 vs. 87.4 min, [Formula: see text]; 2132 vs. 4714 mGy cm, [Formula: see text]). The procedural accuracy, measured as the deviation of the IRE probes with respect to a defined reference probe, was significantly higher using robotic guidance (2.2 vs. 3.1 mm, [Formula: see text]). There were no complications. There was one incomplete ablation in the manual group. CONCLUSION: Robotic assistance for IRE of liver tumors allows for faster procedure times with higher accuracy while reducing radiation dose as compared to the manual placement of IRE probes.

Microwave ablation of large HCC lesions: Added value of CEUS examinations for ablation success control.

PURPOSE: To assess the value of dynamic contrast enhanced ultrasound (CEUS) for the detection of residual tumor tissue day 1 after microwave ablation (MWA) of large hepatocellular carcinoma (HCC) compared to MRI. MATERIAL AND METHODS: 30 consecutive patients (5 females, 25 males, mean age 64 years, age range 54-73 years) with an untreated HCC lesion larger than or equal to 3 cm underwent percutaneous MWA between 03/2014 and 04/2016. 1 patient was excluded because of an artificial pacemaker. All remaining 29 patients underwent 3-T MRI with liver-specific contrast agent and CEUS 1 day after ablation to detect residual tumor tissue. The 6-week follow-up including CEUS and MRI was defined as the reference standard. RESULTS: Complete ablation was achieved in 23 of 29 treated lesions (79%). The sensitivities and specificities for the detection of residual tumor tissue on day 1 were 100% and 83% for CEUS and 87% and 67% for MRI resp. without the differences being statistically significant. CONCLUSION: CEUS allows a reliable assessment of therapeutic success of percutaneous ablation of large HCC lesions one day after the ablation. Its ability to visualize reactive periablation perfusion changes in real-time might be of advantage in the depiction of residual tumor tissue when compared to MRI imaging alone.

Percutaneous irreversible electroporation (IRE) of prostate cancer: Contrast-enhanced ultrasound (CEUS) findings during follow up.

PURPOSE: Irreversible electroporation (IRE) is a focal non-thermal ablation technique that can be used to treat prostate cancer (Pca). The objective was to document the evolution of the volume of the prostate gland and the ablation zone after IRE of Pca. MATERIAL AND METHODS: A retrospective analysis of the image findings of CEUS 1 day, 6 weeks, 3 months and 6 months after IRE of 25 patients was conducted. The prostate gland volumes and the size of the ablation zones were documented. Changes in volume and size over time were calculated. RESULTS: There was a significant volume reduction of the prostate gland in the first 3 months after ablation. The mean percentage change after 6 weeks was 34.3% with another decrease of 35.0% after 3 months. Volume did not change between month 3 and 6. Size of ablation zone measured in short- and long-axis significantly diminished until 6 months after ablation. CONCLUSION: CEUS showed a significant involution of the prostate gland during the first 3 months and a significant decrease of the ablation zone during the first 6 months after IRE of prostate cancer.

Robot-assisted microwave thermoablation of liver tumors: a single-center experience.

PURPOSE: To evaluate and compare the needle placement accuracy, patient dose, procedural time, complication rate and ablation success of microwave thermoablation using a novel robotic guidance approach and a manual approach. METHODS: We performed a retrospective single-center evaluation of 64 microwave thermoablations of liver tumors in 46 patients (10 female, 36 male, mean age 66 years) between June 2014 and February 2015. Thirty ablations were carried out with manual guidance, while 34 ablations were performed using robotic guidance. A 6-week follow-up (ultrasound, computed tomography and MRI) was performed on all patients. RESULTS: The total procedure time and dose-length product were significantly reduced under robotic guidance (18.3 vs. 21.7 min, [Formula: see text]; 2216 vs. 2881 mGy[Formula: see text]cm, [Formula: see text]). The position of the percutaneous needle was more accurate using robotic guidance (needle deviation 1.6 vs. 3.3 mm, [Formula: see text]). There was no significant difference between both groups regarding the complication rate and the ablation success. CONCLUSION: Robotic assistance for liver tumor ablation reduces patient dose and allows for fast positioning of the microwave applicator with high accuracy. The complication rate and ablation success of percutaneous microwave thermoablation of malignant liver tumors using either CT fluoroscopy or robotic guidance for needle positioning showed no significant differences in the 6-week follow-up.

Percutaneous irreversible electroporation (IRE) of prostate cancer: Contrast-enhanced ultrasound (CEUS) findings.

PURPOSE: To evaluate the use of contrast-enhanced ultrasound (CEUS) after irreversible electroporation (IRE) of prostatic cancer tissue to assess the ablation status by depicting microvascularisation in the ablation area. MATERIALS AND METHODS: Retrospective evaluation of CEUS of 13 patients (mean age: 61.4 ± 7.5 years) with histologically confirmed prostatic cancer who underwent percutaneous IRE. In the course of clinical routine, the tumor lesions were documented before, immediately after, and 1 day after the ablationusing color-coded transabdominal and transrectal CEUS. The obtained image data (DICOM loops and images) were subsequently evaluated by 2 experienced radiologists and assessed with regard to micro vascularisation by means of a 5-point scale. RESULTS: CEUS images showed significantly reduced microcirculation of the lesions (mean 0.9 ± 0.6 cm (0.5-1.5 cm) after IRE. Microcirculation was reduced from 2.15 ± 0.56 prior to ablation to 0.65 ± 0.63 (p <  0.001) immediately after the ablation and to 0.27 ± 0.44 one day after IRE (p <  0.001). CONCLUSION: This study showed rapid and significant reduction of the microcirculation in the ablation area afterpercutaneous IRE of prostatic cancer tissue.

Chronic liver disease: Correlation of CEUS-based microperfusion and indocyanine green clearance.

PURPOSE: To evaluate whether changes of dynamic contrast-enhanced ultrasound (CEUS)-based liver microcirculation during chronic liver disease are correlated with the extent of impaired liver function, expressed by the indocyanine green (ICG) clearance. MATERIALS AND METHODS: 19 patients underwent CEUS examinations with previous or consecutive ICG clearance test. The ICG plasma disappearance rate (ICG-PDR) was determined using the noninvasive pulse-densitometric LiMON system. Quantification of peak enhancement (PE), rise time (RT) and the wash-in rate (WiR) was performed in the liver parenchyma (ROIliver) as well as in the portal vein (ROIportal vein) using a novel quantification software (VueBoxTM). To compare quantification parameters, patients were classified in patients representing a healthy population (ICG-PDR >16, n = 8) and those representing patients with liver disease (ICG-PDR ≤16, n = 11). RESULTS: ROIportal vein showed significant differences comparing healthy patients and patients with liver disease for all perfusion parameters: PE and WiR were significantly higher in patients without liver disease (p = 0.048; p = 0.039). RT was significantly lower in healthy population (p = 0.039). Comparing perfusion parameters for ROIliver, PE was significantly higher in patients without liver disease (p = 0.039). There was no significant difference for RT (p = 0.804) and WiR (p = 0.058), respectively. CONCLUSION: Within the framework of this study CEUS derived estimation of microcirculation did not prove to be a reliable estimator of liver function. RT, PE and WiR measured in the portal vein were significant perfusion factors in predicting liver function.

Percutaneous treatment of symptomatic superior mesenteric vein stenosis using self-expanding nitinol stents.

PURPOSE: To evaluate the technical and clinical success of percutaneous superior mesenteric vein (SMV) stenting in symptomatic patients using self-expanding nitinol stents. METHODS: We retrospectively analyzed the technical and clinical success of percutaneous SMV stenting of 6 symptomatic patients (3 men, mean age 67 years, range 48-81 years). Stenosis of the SMV was caused by postoperative stricture (n=3), pancreas carcinoma (n=1) and pancreatitis (n=2). As a result of the stenosis, 3 patients had symptomatic ascites, 2 patients showed signs of mesenteric ischemia and 1 patient had recurrent gastrointestinal bleeding. Stenting was performed by a percutaneous transhepatic approach using self-expanding nitinol stents. RESULTS: Stenting of the SMV was technically and clinically successful in all patients. No peri-interventional complications occurred. The stent diameters ranged from 6 to 14 mm. During the mean follow-up of 6 months (range, 2-10 months) 1 patient presented early stent occlusion 2 weeks after placement. CONCLUSION: Stenting of a symptomatic SMV stenosis using self-expanding nitinol stents is feasible and clinically effective.

S3 guideline for chronic pancreatitis - diagnosis, classification and therapy for the radiologist.

UNLABELLED: Chronic pancreatitis shows an increasing prevalence and incidence mainly in the Western Hemisphere. Early diagnosis and therapy are frequently delayed because of non-specific symptoms as well as non-specific blood values. The German Society of Digestive and Metabolic Diseases (DGVS) organized the preparation and publication of an interdisciplinary S3 level guideline with the support of the German Radiological Society (DRG) as 1 of 11 contributing societies. In this article we present and discuss the main topics of the guideline regarding the diagnosis, differential diagnosis and therapy of complications of this complex chronic disease with a focus on clinical and scientific radiologists. KEY POINTS: • Ultarsound represents the perfect first line imaging modality • For further diagnostic werk up MRI with MRCP are recommended for the differential diagnosis of pancreatic cancer • For clinical studies the modified (CT, MRI) Cambridge classification is recommended.