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BACKGROUND: Differentiation of high-flow from low-flow vascular malformations (VMs) is crucial for therapeutic management of this orphan disease. OBJECTIVE: A convolutional neural network (CNN) was evaluated for differentiation of peripheral vascular malformations (VMs) on T2-weighted short tau inversion recovery (STIR) MRI. METHODS: 527 MRIs (386 low-flow and 141 high-flow VMs) were randomly divided into training, validation and test set for this single-center study. 1) Results of the CNN's diagnostic performance were compared with that of two expert and four junior radiologists. 2) The influence of CNN's prediction on the radiologists' performance and diagnostic certainty was evaluated. 3) Junior radiologists' performance after self-training was compared with that of the CNN. RESULTS: Compared with the expert radiologists the CNN achieved similar accuracy (92% vs. 97%, p = 0.11), sensitivity (80% vs. 93%, p = 0.16) and specificity (97% vs. 100%, p = 0.50). In comparison to the junior radiologists, the CNN had a higher specificity and accuracy (97% vs. 80%, p < 0.001; 92% vs. 77%, p < 0.001). CNN assistance had no significant influence on their diagnostic performance and certainty. After self-training, the junior radiologists' specificity and accuracy improved and were comparable to that of the CNN. CONCLUSIONS: Diagnostic performance of the CNN for differentiating high-flow from low-flow VM was comparable to that of expert radiologists. CNN did not significantly improve the simulated daily practice of junior radiologists, self-training was more effective. [ABSTRACT FROM AUTHOR]

BACKGROUND: Rapid evolution of ultrasound technology has allowed widespread use of handheld ultrasound devices (HHUDs) for many possible applications. Along with the adult population, the use of HHUDs for Point of Care Ultrasound (POCUS) in pediatric medicine has been increasing over the last few years. However, pediatric-specific literature is still scarce on mobile vascular ultrasound. OBJECTIVE: To evaluate diagnostic capabilities of Vscan Air™ in comparison with high-end ultrasound for the assessment of the internal jugular vein in children and adolescents. METHODS: 42 Internal Jugular Veins (IJVs) of 21 pediatric patients were scanned by an experienced examiner using a WLAN-supported handheld ultrasound device (Vscan Air™) and high-end cart-based ultrasound (LOGIQ E9) as reference. B-Mode and Color-coded Doppler (CCDS) were performed and compared. Image quality was assessed using a score of 0 to 5 and statistically analyzed. Results were interpreted independently by two readers in consensus. RESULTS: 21 patients (2–17 years; mean 11,00±4,5 years; female n = 11, male n = 10) were examined. The rating score never dropped below 3 for both devices. The median score evaluation of B-Mode and CCDS for the high-end device was 5.00, of Vscan Air™ 5.00 for B-Mode and 4.00 for CCDS. A significant difference was shown between the two devices in the evaluation of CCDS. CONCLUSIONS: Vscan Air™ ultrasound device allows sufficient assessability of the IJV in pediatric patients, opening up new possibilities for fast and mobile POCUS of cervical veins and potential guidance of central venous catheter placement. [ABSTRACT FROM AUTHOR]

BACKGROUND: The continuous development of ultrasound techniques increasingly enables better description and visualization of unclear lesions. New ultrasound systems must be evaluated with regard to all these diagnostic possibilities. METHODS: A multifrequency C1-7 convex probe (SC7-1M) with the new high-end system Resona A20 Series was used. Modern technologies, including HiFR CEUS, SR CEUS and multimodal tissue imaging with shear wave elastography (SWE), fat evaluation and viscosity measurements (M-Ref) were applied. RESULTS: Of n = 70 (mean value 48,3 years±20,3 years, range 18–84 years) cases examined, a definitive diagnosis could be made in n = 67 cases, confirmed by reference imaging and/or follow-up. Of these, n = 22 cases were malignant changes (HCC (hepatocellular carcinoma) n = 9, CCC (cholangiocellular carcinoma) n = 3, metastases of colorectal carcinomas or recurrences of HCC n = 10). In all 12 cases of HCC or CCC, the elastography measurements using the shear wave technique (with values >2 m/s to 3.7 m/s) showed mean values of 2.3±0.31 m/s and a degree of fibrosis of F2 to F4. In n = 14 cases, changes in the fat measurement (range 0.51 to 0.72 dB/cm/MHz, mean values 0.58±0.12 dB/cm/MHz) in the sense of proportional fatty changes in the liver were detected. In the 4 cases of localized fat distribution disorders, the values were >0.7 dB/cm/MHz in the sense of significant fatty deposits in the remaining liver tissue. Relevant changes in the viscosity measurements with values >1.8 kPa were found in n = 31 cases, in n = 5 cases of cystic lesions with partially sclerosing cholangitis, in n = 13 cases of malignant lesions and in n = 9 cases post-interventionally, but also in n = 4 cases of benign foci with additional systemic inflammation. CONCLUSIONS: The results are promising and show a new quality of ultrasound-based liver diagnostics. However, there is a need for further investigations with regard to the individual aspects, preferably on a multi-center basis. [ABSTRACT FROM AUTHOR]

AIM: To evaluate the usefulness of handheld ultrasound in comparison with high-end ultrasound for lesion evaluation before and after sclerotherapy in pediatric patients with venous malformations (VMs). MATERIAL AND METHODS: 10 pediatric patients prior to and after sclerotherapy were scanned by an experienced examiner using handheld ultrasound (Vscan AirTM) and high-end ultrasound (LOGIQ E9/E10) as reference. Patients with associated venous thromboses and intralesional aneurysms had been excluded. Results were interpreted independently by two readers in consensus. RESULTS: 10 patients (4-17 years; 10.0±4.32 years; female n = 6, male n = 4) with 10 VMs (4 of the head and neck region, 4 of the upper and 2 of the lower extremities) were examined. 7 phleboliths were detected. The average rating score achieved by the high-end device never was less than 4, by Vscan AirTM never less than 3. An exception was the assessment of AV fistulas. In comparison with the evaluation of variables examined, we found a significant difference between the high-end scanner and the handheld device regarding the achieved image quality. CONCLUSION: Vscan AirTM ultrasound device allows new possibilities for procedure planning and post-procedural control of pediatric patients with VMs. [ABSTRACT FROM AUTHOR]

BACKGROUND: Local ablation is an important treatment for liver cancer in cases of cirrhosis. Liver failure may occur after ablation, especially in advanced liver diseases. Currently, there is no standardization for peri-interventional risk assessment. The liver maximum capacity test (LiMAx) is used to assess functional liver capacity, but there is a lack of exploration of its use in this context. OBJECTIVE: The aim of this study was to retrospectively evaluate the usefulness of peri-interventional LiMAx measurements in patients with primary or secondary liver cancer who underwent ablation treatment. METHODS: A LiMAx test was performed at 24 hours pre- and postablation in 49 patients. Blood parameters were collected to determine liver function using MELD and ALBI scores. The results of the LiMAx test were related with these scores and to critical postintervention LiMAx values. RESULTS: LiMAx values correlated strongly with MELD and ALBI scores before the intervention and reflected the change in liver function, as shown by an increase in scores after the intervention. Notably, LiMAx values decreased during the intervention. AUC analysis for patients at risk of reaching a critical liver level after the intervention showed a cutoff value of 186μg/kg/h. CONCLUSIONS: The LiMAx test may be a valuable tool in liver ablation for both peri-interventional monitoring of liver function and preintervention risk assessment. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The study aim was to investigate the use of a novel device, the Vscan Air™, for rapidly and effectively performing ultrasound in student teaching during the COVID-19 pandemic. MATERIAL AND METHODS: As part of the ultrasound practical course with integrated hands-on activity required by the regular medical curriculum, 100 medical students were instructed in the use of the Vscan Air™, including duplex mode. They then evaluated the quality of the ultrasound images obtained by the Vscan Air™ from previously selected organs. RESULTS: 100 students were interviewed (female n = 68, male n = 32; age >18 years n = 100). The rated image quality never fell below a mean of 3 for the examined organs and portal vein flow (liver 4,58; spleen 3,99; kidneys 4,29; aorta 4,16; Douglas/rectovesical space 4,14; portal vein 4,43; pancreas 3,53; Focused Assessment with Sonography for Trauma 4,38). Scores below 3 were found sporadically in ultrasounds of the spleen (n = 4), kidneys (n = 3), Douglas/rectovesical space (n = 2), and pancreas (n = 15). The liver was rated the lowest for 59 ratings. The portal vein was evaluated in 68 cases. The hepatic artery and hepatic veins could be also visualized in all 68 examinations. The aorta was evaluated in 62 cases. CONCLUSION: The Vscan Air™ technology offered adequate image quality and provided a new, fast and patient-oriented technique to support continuous ultrasound examinations and education of students, especially during a pandemic. Particularly noteworthy is the uncomplicated compliance with the required high level of hygiene. [ABSTRACT FROM AUTHOR]

OBJECTIVE: This study aimed to evaluate a new W-Lan-supported ultrasound mobile technology for the diagnosis of vascular peripheral thrombosis. MATERIAL and METHODS: Fifty patients were examined by an experienced reference sonographer using high-end technology and a W-Lan supported device (VScan Air) to evaluate its diagnostic capabilities for peripheral thrombosis. RESULTS: Fifty patients were examined (age, 25–88 years; male, n = 27, female n = 23). Thromboses were diagnosed in the neck (n = 1), upper leg (n = 7), lower leg (n = 49), and muscle veins (n = 25). VScan Air technique also allows the diagnosis of circumscribed deep vein thrombosis with a sufficient diagnostic certainty. Moreover, for superficial thrombi that can be well-delineated, a maximum image quality is possible compared to high-end technology. CONCLUSION: The mobile VScan technology opens up new possibilities for near-patient and location-independent imaging in cases of deep vein thrombosis. [ABSTRACT FROM AUTHOR]

AIM: To examine to what extent the high frame rate contrast-enhanced ultrasound (HiFR) diagnostic enables the conclusive diagnosis of liver changes with suspected malignancy. MATERIAL/METHODS: Ultrasound examinations were performed by an experienced examiner using a multifrequency probe (SC6-1) on a high-end ultrasound system (Resona 7, Mindray) to clarify liver changes that were unclear on the B-scan. A bolus of 1–2.4 ml of the Sulphur hexafluoride ultrasound microbubbles contrast agent SonoVue™ (Bracco SpA, Italy) was administered with DICOM storage of CEUS examinations from the early arterial phase (5–15 s) to the late phase (5–6 min). Based on the image files stored in the PACS, an independent reading was performed regarding image quality and finding-related diagnostic significance (0 not informative/non-diagnostic to 5 excellent image quality/confident diagnosis possible). References were clinical follow-up, if possible, comparison to promptly performed computed tomography or magnetic resonance imaging, in some cases also to histopathology. RESULTS: We examined 100 patients (42 women, 58 men, from 18 years to 90 years, mean 63±13 years) with different entities of focal and diffuse liver parenchymal changes, which could be detected in all cases with sufficient image quality with CEUS and with high image quality with HiFR-CEUS. Proportionally septate cysts were found in n = 19 cases, scars after hemihepatectomy with local reduced fat in n = 5 cases, scars after microwave ablation in n = 19 cases, hemangiomas in n = 9 cases, focal nodular hyperplasia in n = 8 cases, colorectal metastases in n = 15 cases, hepatocellular carcinoma (HCC) in n = 11 cases, Osler disease in n = 8 cases. The size of lesions ranged from 5 mm to 200 mm with a mean value of 33.1±27.8 mm. Conclusive diagnoses could be made by the experienced investigator in 97/100 cases with CEUS, confirmed by reference imaging, in parts by histopathology or follow-up. The image quality for HiFR CEUS was rated with a score of 3 to 5; 62 cases were assessed with an average of good (4 points), 27 cases with very good (5 points), and in 11 cases (3 points) still satisfactory despite aggravated acoustic conditions. The specificity of HIFR-CEUS was 97%, the sensitivity 97%, the positive predictive value 94%, the negative predictive value 99% and the accuracy 97%. CONCLUSION: HIFR-CEUS has demonstrated has demonstrated an improved image quality resulting in a high diagnostic accuracy. In the hands of an experienced investigator, HiFR-CEUS allows the assessment of focal and diffuse unclear liver parenchymal changes on B-scan and dynamic assessment of microcirculation in solid and vascular changes. [ABSTRACT FROM AUTHOR]

BACKGROUND: Ultrasound follow-up of transjugular intrahepatic portosystemic shunt (TIPS) is challenging due to the bent course of the stent-graft. OBJECTIVE: Aim of this retrospective study was to assess to which extent the combination of HR flow with Glazing Flow improves hemodynamic assessment in the ultrasound follow-up of TIPS. METHODS: Comparative studies with CCDS and High Resolution (HR)-Flow with Glazing Flow were evaluated regarding image quality and artifacts on a 5-point scale (0 = cannot be assessed up to 5 = maximum image quality without artifacts). In all cases, an experienced examiner performed the examinations with a 1–6 MHz probe (Resona 7, Mindray). RESULTS: 61 ultrasound examinations in 48 patients were performed; the mean patient age was 54±14.2 years. The use of HR-Flow with Glazing Flow resulted in an improved flow display in 55/61 cases (90.2%). Both methods correlated well (r = 0.71), but HR flow with Glazing flow values were in general higher than CCDS values. The reading resulted in an average value of 2.52±0.54 for CCDS and 3.52±0.57 for HR flow with Glazing flow (p = 0.013). CONCLUSION: The combination of HR-Flow and Glazing Flow results in improved flow representation and reduction of artifacts in the ultrasound follow-up of TIPS. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVE: Liver function is one of the most important parameters for the outcome of transarterial chemoembolization (TACE). The liver maximum capacity (LiMAx) test is a bedside test that provides a real-time option for liver function testing. The objective of this pilot study was to investigate the suitability of the LiMAX test for predicting the TACE outcome. METHODS: 20 patients with intermediate-stage hepatocellular carcinoma (HCC) received a LiMAx test 24 h pre and post TACE. In addition, laboratory values were collected to determine liver function and model for endstage liver disease (MELD) scores. The success of TACE was assessed 6 weeks post intervention by morphological imaging tests using modified response evaluation criteria in solid tumors (mRECIST). RESULTS: Patients with an objective response (OR = CR + PR) according to mRECIST post TACE had significantly higher values in the pre-interventional LiMAx test than patients with a non-OR (PD or SD) post TACE (r(14) = 0.62, p = 0.01). Higher pre-interventional LiMAx values therefore indicate OR. Patients with a disease control (DC = CR + PR + SD) according to mRECIST post TACE had significantly higher values in the pre-interventional LiMAx test than patients with a non-DC (PD) post TACE (r(14) = 0.65, p = 0.01). Higher pre-interventional LiMAx values therefore indicate DC. The point biserial correlations of LiMAx values pre and post TACE with the outcome OR or DC were descriptively stronger than those of MELD with OR or DC. This suggests that the LiMAx test correlates better with the treatment response than the MELD score. CONCLUSIONS: For the first time, we were able to show in our study that patients who are scheduled for TACE could benefit from a LiMAx test to be able to estimate the benefit of TACE. The higher the pre-interventional LiMAx values, the higher the benefit of TACE. On the other hand, laboratory parameters summarized in the form of the MELD score had significantly less descriptive correlation with the TACE outcome. [ABSTRACT FROM AUTHOR]

AIM: To evaluate the effectiveness of complementary imaging of high-resolution ultrasound including CEUS with PET/CT for tissue characterization and tumor detection. MATERIAL AND METHODS: 100 patients were examined with PET/CT and US/CEUS between January 2018 until February 2020. All patients underwent PET/CT followed by selective US/CEUS within 4 weeks. Comparison regarding concordant or diverging findings in PET/CT and US. Analysis of the differences concerning the lesions number of found by PET/CT and US/CEUS or the possibility of a secured diagnosis following ultrasound causing therapeutic changes. RESULTS: Diverging findings regarding the number of liver lesions in PET/CT and CEUS were found in 35 out of 64 patients (54%). Regarding renal lesions, a more definite diagnosis following ultrasound, causing a change of therapeutic approach, was achieved in 89%. Concordant results in PET/CT and US were found in 83% of patients with splenic and nodal findings. In 78% of patients with increased musculoskeletal or soft tissue tracer uptake, US was able to make a secured diagnosis with therapeutic changes. CONCLUSION: The present results indicate a strong benefit of complementary imaging of PET/CT and selective, high-resolution ultrasound especially in patients with liver, renal and musculoskeletal or soft tissue findings. [ABSTRACT FROM AUTHOR]

To assess diagnostic capabilities of a modern handheld ultrasound device (HUD) for portal vein (PV) evaluation in pediatric patients and to verify if age, body mass index (BMI) and object depth correlate to imagequality.45 patients (3.9 months– 17.9 years; 10.3 years±5.4) were examined using a HUD and cart-based high-end ultrasound system (HEUS). The intra-and extrahepatic PV was scanned using B-Mode and Color-coded Doppler sonography (CCDS). A five-point Likert scale was applied to evaluate image quality. Results were interpreted by two readers in consensus. Scores were compared between the scanners and correlated to age, BMI and skin-to-portal-vein-distance (SPVD). The influence on image quality and the difference between the two devices were analyzed using ordinal and Bayesian logistic regression models.≥4 points (mild or no limitations) were achieved by the HUD in 60% for B-Mode and 56% for CCDS. There was a statistically significant negative correlation between the image quality achieved by the HUD and the SPVD for B-Mode and CCDS. The effect of BMI and SPVD on having≥4 points differed significantly between the HUD and HEUS for B-Mode (OR = 0.191, p = 0.005, and OR = 0.040, p = 0.008) and for CCDS (OR = 0.209, p = 0.009, and OR = 0.084,p = 0.011).Sufficient to excellent image quality for portal vein assessment in pediatric patients was achieved by the HUD except for the most deep-lying structures. Compared to HEUS, diagnostic performance of the HUD is lower, based on a negative correlation with object depth. [ABSTRACT FROM AUTHOR]

AIM: The aim of this study was to assess the success of irreversible electroporation (IRE) in prostate cancer and to differentiate between reactive changes and tumor. MATERIAL AND METHODS: This is a retrospective pilot study of 50 patients after irreversible electroporation (IRE) in prostate cancer between 50–79 years (mean age 65 years). Each patient received a transabdominal sonography using a 1–6 MHz convex matrix probe. Contrast-enhanced ultrasound (CEUS) was performed after i.v. bolus injection of 2.0 ml sulphur hexafluoride microbubbles. DICOM loops were continuously stored up to one minute. Parametric images were calculated by integrated perfusion analysis software. A comparison was drawn to a follow-up MRI six months after ablation. RESULTS: While 13 patients showed local recurrence, 37 patients were successfully treated, meaning no local recurrence within six months after ablation. 18 patients showed signs of prostatitis after IRE. Tumorous changes were visually characterized by dynamic early nodular hypervascularization with fast and high wash-in. Correspondingly, nodular red and yellow shades were seen in parametric imaging. All patients with remaining tumor were correctly identified with CEUS and parametric imaging. After IRE there is a relevant decrease in tumor microcirculation in all patients, as seen in more purple shades of the prostate. The sensitivity for detecting residual tumor with CEUS compared to MRI was 76%, the specificity was 81%. The corresponding positive predictive value (PPV) was 73% and the negative predictive value (NPV) was 83%. CONCLUSION: CEUS and parametric imaging enable a critical analysis of post-ablation defects after IRE for prostate cancer even with a transabdominal approach. Remaining tumor can be detected with the help of pseudo-colors. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To investigate the diagnostic accuracy of high-resolution ultrasound (HRU) for the detection of hepatic metastases of breast cancer in a humanized tumour mouse (HTM) using clinical standard technology. In addition, the efficiency of standard contrast-enhanced ultrasound (CEUS) [microbubbles of sulphur hexafluoride] and CEUS using a novel VEGFR2-targeted contrast agent [BR55®] was examined. METHODS: A total of 14 HTM were sonographically examined twice. In addition to a human immune system, the animals developed hepatic tumour lesions after intrahepatic injection of BT-474 breast cancer cells. Digital cine loops from the arterial phase (15–35 sec), the portal venous phase (35–90 sec) and the late phase (3–15 min) of the entire liver were analysed. Data were correlated to histopathology. RESULTS: After 9 months, half of the mice (7/14) revealed the development of hepatic breast cancer metastases. The detection limit was 1 mm tumour diameter. In particular, the use of targeted contrast media reduced the needed tumour diameter and helped to precisely classify tumour tissue. In 93% (13/14), the findings of ultrasound could be approved by histological examination by the pathologist. CONCLUSIONS: This study in HTM demonstrated the high feasibility of tumour specific contrast media and standard HRU contrast agents to detect early liver metastases. [ABSTRACT FROM AUTHOR]

Gadolinium ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) is a hepatocyte-specific, linear ionic contrast agent for MRI. In comparison to other linear contrast agents Gd-EOB-DTPA is excreted equally through liver and kidneys. This prospective longitudinal study investigates the signal intensity (SI) in the dentate nucleus (DN) on unenhanced T1-weighted images after repetitive application of Gd-EOB-DTPA. 46 patients were included into the study and 107 MRI examinations were performed. Statistical analysis of 25 patients showed no significant correlation between cumulative dose of Gd-EOB-DTPA and SI change and between the DN/Pons ratiolast and the mean DN/Pons ratiofirst. Subgroup analysis however revealed a significant correlation for one out of two readers. Gd-EOB-DTPA deposition could not be proven in the framework of this study. [ABSTRACT FROM AUTHOR]

AIM: Evaluation of the post-interventional success following ablative techniques (radiofrequency and microwave) using a new color coded perfusion quantification software with CEUS in patients with primary and secondary liver malignancies. MATERIAL AND METHODS: 75 patients (60 males, 15 females, age 24–84 years, mean 62.7 years) with 128 malignant liver lesions were included in this study. Between 01/2013 and 06/2018, the therapeutic interventional procedure in 88 lesions was MWA, in 40 lesions RFA. All patients underwent CEUS using a convex multifrequency probe (1–6 MHz) following application of 1–2.4 ml sulphur hexaflouride microbubbles, before and within 24 hours following RFA and MWA to detect residual tumor tissue. Postprocessing of the stored DICOM loops from 15 sec up to 1 min using a perfusion quantification software regarding peak enhancement (pE), time to peak (TTP), mean transit time (MTT), rise time (Ri) and Wash-in area under the curve (WiAUC) in the center of the lesion, the border area and periphery was performed. RESULTS: In patients treated with RFA, pE differences between center of the lesion vs. surrounding liver were found to be statistically extremely significant (p < 0.001), differences between center of the lesion and margin were also statistically significant (p < 0.01). mTT, TTP, WiAuC and Ri showed no significant difference between center, margin or surrounding liver. In patients treated with MWA, statistically significant differences (p < 0.05) were found for pE, Ri and mTT regarding the differences between center of lesion and surrounding tissue. WiAuC and TTP showed no significant differences between center, margin or surrounding liver. CONCLUSION: CEUS with perfusion imaging is a valuable supporting tool for post-interventional success control following RFA and MWA of primary and secondary liver maligancies. Focus should be placed upon pE following MWA and pE, Ri and mTT following RFA. [ABSTRACT FROM AUTHOR]

AIM: To assess the influence of difficult examination conditions onto the diagnostic performance of CEUS (contrast-enhanced ultrasound) in focal liver lesions (FLL). METHODS: 77 liver CEUS examinations of 75 patients were analysed retrospectively. CEUS was performed as the first diagnostic procedure by one experienced sonographer after bolus injection of 1.0 up to 2.4 ml sulphur hexafluoride microbubbles using a high-end ultrasound device with a high resolution multifrequency probe (1–6 MHz). The combination of complementary imaging (CT or MRI), histology and CEUS follow up of at least 6 months was considered. Cross tables were used to define the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy. Chi-Square Test analysed categorical data. RESULTS: The patients were between 18 and 84 years old (mean 62±11 years). 26 patients suffered from liver cirrhosis (33.8%). 52 patients (67.5%) received therapy for an oncological disease. The final diagnosis showed 52 malignant FLLs including 24 hepatocellular carcinomas (HCCs), 9 cholangiocellular carcinomas (CCCs) and 19 metastases from different primary tumors. In the other 25 patients no malignant lesions could be detected, three of them presenting however liver haemangioma and two of them liver cysts. The overall lesions' size according to the CEUS findings ranged from 7 to 100 mm (mean 31.1±22.6 mm). Under good examination conditions the malignant potential of a tumor was diagnosed correctly by CEUS in 98.0% of cases (Sensitivity 97.1%, Specificity 100%, PPV 100%, NPV 94.1%, diagnostic accuracy 98.0%). Limited examination conditions (e.g. obesity, meteorism) were present in 35.1% of cases with a decrease of the diagnostic accuracy to 92.6% (Sensitivity 100%, Specificity 77.8%, PPV 90.0%, NPV 100%). CONCLUSION: Despite the influence of difficult examination conditions, CEUS is – in the hands of an experienced sonographer – an excellent diagnostic procedure for the assessment of liver lesions. [ABSTRACT FROM AUTHOR]

PURPOSE: Contrast enhanced magnetic resonance imaging (MRI) is able to assess liver function by characteristic changes of signal intensity (SI). The aim was to evaluate dynamic contrast-enhanced SI-indices of the abdominal aorta, portal vein and liver. METHODS: 72 patients underwent Gd-EOB-DTPA-enhanced MRI and a 13C-methacetin-based liver breath test (13C-MBT) for evaluation of liver function. Region-of-interest measurements in the liver, abdominal aorta and portal vein during native, arterial (AP), late arterial (LAP), portal venous (PVP) and hepatobiliary phase (HBP) were applied to analyze SI-indices in T1-weighted volume-interpolated breath-hold examination (VIBE) sequences with fat-suppression and relative enhancement (RE) analysis was performed. RESULTS: The liver (p < 0.001), the portal vein (p < 0.001) and abdominal aorta (p = 0.002) showed significant decrease of REs with decreasing liver function. An increasing trend between logarithmic values of 13C-MBT and REs of hepatic parenchyma (HBP; r = 0.662, p < 0.001), portal vein (PVP; r = 0.532, p < 0.001) and abdominal aorta (PVP; r = 0.421, p < 0.001) was observed. CONCLUSIONS: RE measurements of the hepatic parenchyma proofed to be a trustable evaluation method for liver function evaluation. In accordance with liver function, changes of REs in the portal vein and abdominal aorta occur. [ABSTRACT FROM AUTHOR]

BACKGROUND: The diagnostic value of Doppler ultrasonography of the portal vein for the evaluation of liver function is still contradictory. OBJECTIVE: Aim of this study was to test the relationship between clinical liver function tests based on MRI and breath testing and blood flow in the portal vein. METHODS: The portal vein velocity was measured by color coded Doppler ultrasonography (CCDS) and tested against the relative enhancement (RE), a MRI-based index of liver function. The signal intensity in the liver parenchyma was assessed before (pre) and after (post) administration of contrast agent, the RE was calculated afterwards. Further, the liver function was also assessed using a 13C-Methacetin-based breath test. The blood flow in the portal vein was tested for possible correlation applying Pearson's correlation coefficient. RESULTS: Using CCDS, all patients show a hepatopetal portal blood flow. The portal vein velocity is decreasing with progression of liver damage and there was a significant correlation of portal velocity with SI post (r = 0.411, p = 0.024). However, the portal velocity did not correlate significantly with the 13C-MBT readout (r = 0.233; p = 0.216), SI pre (r = 0.271, p = 0.147) or the relative enhancement (r = 0.303; p = 0.103). CONCLUSIONS: The results of this proof-of-principle study indicate that CCDS-based assessment of portal velocity is of only limited value for the evaluation of liver function. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To identify the indications for CEUS in renal imaging in an interdisciplinary ultrasound department. METHODS: 102 CEUS examinations of the kidney in 82 patients between September 2014 and July 2016 were analysed regarding the indication for ultrasound. CEUS was performed by one experienced sonographer agent after bolus injection of 1.0 up to 2.4 ml sulphur hexafluoride microbubbles using multifrequency probes with Contrast Harmonic imaging. RESULTS: CEUS of the kidney was performed in patients from 20 to 87 years. 44% of the patients had a stage 3 of chronic kidney disease and higher 38% of the patients had undergone a renal transplantation. No adverse events were observed. 54% of examinations were requested by nephrologists. The remaining by surgeons, oncologists or gastroenterologists. In 47% the objectives were the evaluation of complex renal cysts, in 31% the analysis of kidney perfusion, in 19% the assessment of solid renal masses. The remaining were perirenal tumours (2%) and infection (1%). CONCLUSIONS: CEUS is a good diagnostic alternative for patients with impaired renal function, complicated cysts, infections, solid renal lesions and after renal transplant. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Correct preoperative detection of parathyroid gland adenoma (PA) in the case of primary hyperparathyroidism (pHPT) is the requirement for unilateral cervical exploration associated with lower morbidity. We present our experience with contrast-enhanced ultrasonography (CEUS) as diagnostic tool for the preoperative localization of PA in pHPT in comparison to the 99mTechnetium-sestamibi scintigraphy. METHODS: Between 8/2009-5/2013 143 patients with pHPT received surgical interventions in the Department of Surgery at the University Hospital of Regensburg. In all patients contrast-enhanced ultrasonography (CEUS) was performed as diagnostic tool for the localization of pathological parathyroid glands. By one experienced examiner CEUS was performed after bolus injection of 1-2.4 ml contrast agent with storage of digital cine loops from the arterial phase (15-45 s) to the late phase (3 Min). Criteria for a parathyroid adenoma were marginal hypervascularisation in the arterial phase and wash out in the late phase. 74 patients received 99mTechnetium-sestamibi scintigraphy. The sensitivity of both diagnostic tools was analyzed in comparison to the intraoperative and histological findings. RESULTS: CEUS revealed a sensitivity of 95.9% for the detection of pathological parathyroid glands and even of 97.1% for patients without scintigrapy in comparison to 60.8% for 99mTechnetium-sestamibi scintigraphy. Sensitivity of CEUS in patients with negative scintigraphy was 96.3%. In multivariate regression analysis detection of small PA compared to scintigraphy was better by trend but did not reach significance (p = 0.019). Follow-up with a minimum of 8 weeks showed normal serum levels of calcium and parathyroid hormone in all patients except one. CONCLUSIONS: CEUS represents a new diagnostic method for the localization of parathyroid gland adenomas independent on findings in scintigraphy. In the present of appropriate expertise in CEUS no further diagnostic procedures are required. [ABSTRACT FROM AUTHOR]

AIM: Identification of acute and subacute complications following pancreas and renal transplantation using contrast enhanced ultrasound (CEUS) in comparison with Magnetic Resonance Tomography (MRI), Computed Tomography (CT), Digital Subtraction Angiography (DSA) or Ultrasound (US). The study evaluated whether CEUS could confirm the preliminary diagnosis or even provide additional information, relevant for the therapeutic strategy. MATERIAL AND METHODS: Retrospective evaluation of 19 patients (13 male, 6 female, age 26-77 years, mean 53.2 years) following renal transplantation and 10 patients (4 male, 6 female, age 35-56 years, mean 45.7 years) following combined pancreas and renal transplantation. CEUS was used as an additional diagnostic method when obscure diagnostic findings occurred in US, CT, MRI or DSA. Fundamental B-scan, Color Coded Doppler Sonography (CCDS) and CEUS were performed in all patients by an experienced examiner using a multifrequency convex transducer (1-5 MHz). After a bolus injection of up to 2.4 ml SonoVue® [BRACCO, Italy] digital raw data was stored as cine-loops up to 5 minutes in length. RESULTS: In all patients, the pathological features and suspected diagnostic findings identified in the other imaging modalities could be confirmed using CEUS (100%). In 25 out of 29 patients (86.2%), new clinically relevant findings were detected. In 27 patients, the diagnosis of CEUS was confirmed during surgery (7), DSA (5), follow-up CEUS (13), CT (1) and MRI (1). In 4 patients renal AV-fistulas were found following biopsy, 3 patients showed post-operative allograft arterial stenosis or dissection, 1 patient demonstrated a stenosis of the common iliac artery and 2 patients were diagnosed with post-operative allograft venous thrombosis or stenosis. In 2 patients, a definite diagnosis of a benign lesion following renal transplantation was possible. In 1 patient a malignant lesion was suspected and confirmed following surgery. In 6 patients, normal perfusion of the pancreas and renal parenchyma and the corresponding vessels was diagnosed, in 5 patients the parenchymal perfusion was diminished and 1 patient suffered from pancreatitis. CONCLUSION: These first results show that CEUS can provide additional, clinically relevant informations in patients with acute and subacute complications following pancreas and renal transplantation. Thus, an early application within the diagnostic course seems favorable. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To evaluate treatment response of hepatocellular carcinoma (HCC) after transarterial chemoembolization (TACE) with a new real-time imaging fusion technique of contrast-enhanced ultrasound (CEUS) with multi-slice detection computed tomography (CT) in comparison to conventional post-interventional follow-up. MATERIAL AND METHODS: 40 patients with HCC (26 male, ages 46-81 years) were evaluated 24 hours after TACE using CEUS with ultrasound volume navigation and image fusion with CT compared to non-enhanced CT and follow-up contrast-enhanced CT after 6-8 weeks. Reduction of tumor vascularization to less than 25% was regarded as 'successful' treatment, whereas reduction to levels >25% was considered as 'partial' treatment response. Homogenous lipiodol retention was regarded as successful treatment in non-enhanced CT. RESULTS: Post-interventional image fusion of CEUS with CT was feasible in all 40 patients. In 24 patients (24/40), post-interventional image fusion with CEUS revealed residual tumor vascularity, that was confirmed by contrast-enhanced CT 6-8 weeks later in 24/24 patients. In 16 patients (16/40), post-interventional image fusion with CEUS demonstrated successful treatment, but follow-up CT detected residual viable tumor (6/16). Non-enhanced CT did not identify any case of treatment failure. Image fusion with CEUS assessed treatment efficacy with a specificity of 100%, sensitivity of 80% and a positive predictive value of 1 (negative predictive value 0.63). CONCLUSIONS: Image fusion of CEUS with CT allows a reliable, highly specific post-interventional evaluation of embolization response with good sensitivity without any further radiation exposure. It can detect residual viable tumor at early state, resulting in a close patient monitoring or re-therapy. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To assess the effects of vascular-disrupting agent (VDA)-based therapy including monitoring of therapeutic efficacy with contrast-enhanced ultrasound (CEUS) in a gastric cancer model. MATERIALS & METHODS: Gastric cancer cell lines and endothelial cells were used. Effects of the VDA ASA404 on cells were determined by MTT assays and Western blotting in vitro. Therapeutic efficacy of ASA404 was assessed in vivo in a subcutaneous mouse model in combination with paclitaxel. CEUS with TIC (time intensity curve) analyses was employed to measure tumor perfusion. Finally, tumor tissue was harvested and processed for histological work-up. RESULTS: In vitro, ASA404 impaired growth of ECs upon stimulation with conditioned media from gastric cancer cells. No direct effects on tumor cells were observed. In vivo treatment with ASA404 in combination with paclitaxel led to significant decrease of tumor microvascularization as determined by CEUS. Furthermore, combination of ASA404 with paclitaxel showed a significant inhibition of tumor growth which was paralleled by strong reduction of tumor cell proliferation and vessel area. CONCLUSION: VDA-based therapy in combination with paclitaxel, and therapy monitoring by CEUS, appears to be a promising strategy for gastric cancer. [ABSTRACT FROM AUTHOR]

Background: Preoperative differentiation of thyroid nodules in benign and malignant pathologies still represents an unsolved problem in endocrinology. In the presented study, contrast-enhanced ultrasonography (CEUS) was applied as a new diagnostic tool detecting the microvascularisation of thyroid carcinomas. Methods: 167 patients underwent surgery for suspicious thyroid nodules between 05/2011 and 08/2012. Contrast-enhanced ultrasonography (CEUS) with a linear probe (6-9 MHz, LOGIQE9/GE), color coded Doppler sonography (CCDS) and Power Doppler ultrasonography (PD) were performed in all patients preoperatively. Removed nodules were proved by histology. In case of carcinoma morphological characteristics and especially microvascularization were analyzed using time intensity curves (TIC) in selected regions of interest (ROI). Results: In total, 22 thyroid carcinomas could be identified by histology. Using CEUS thyroid carcinomas in 19 patients showed early and irregular arterial vascularization followed by early arterial central wash-out. CCDS/PD, however, revealed irregular peripheral vascularization with low flow only in 8 cases. Further analysis resulted in a significant higher area under the curve (AUC) at the edge than in the tumor center but in a similar time to peak (TTP) in both regions. Conclusions: CEUS represents a highly sensitive method for the detection of the microvascularization of thyroid carcinomas. Future studies should compare these findings to benign pathologies in order to establish CEUS as a standard diagnostic procedure in the preoperative evaluation of suspicious thyroid nodules. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to evaluate the value of linear contrast enhanced intraoperative ultrasound (CE-IOUS) to improve detection of malign liver tumors lesions before surgery or radiofrequency ablation (RFA). Materials and Methods: 50 patients were included for surgery of malignant liver tumors (mean age 61 years (19-80); male n = 35, female n = 15), suffering from HCC (n = 15), colorectal liver-metastasis (n = 28), CCC (n = 2) or other malign liver lesions (n = 5). Preoperative CE-CT (n = 38), CE-MRI (n = 23) or PET-CT (n = 8) confirmed hepatic tumor manifestation. Before undergoing surgery, intraoperative conventional (IOUS) as well as CE-IOUS were performed by one experienced examiner in all cases using multifrequency linear probes (6-9 MHz, 6-15 MHz; LOGIQ E9; GE Healthcare, Milwaukee, WI, USA). CE-IOUS was performed after bolus injection of 5 ml up to 15 ml SonoVue® (Bracco Imaging SpA, Milan, Italy). Digitally stored images of CE-IOUS were compared with fundamental B-Scan and preoperative imaging (CE-CT, CE-MRI and PET-CET). Results: In 28 of 50 patients (56%), additional lesions were found using CE-IOUS (mean tumor size 8 mm, range 4-12 mm). This resulted in a change of surgical strategy or the intraoperative application of RFA in 27 patients (54%). Modification of therapy due to additionally found liver lesions was statistically significant (p < 0.05). Comparing conventional IOUS and CE-IOUS, 14 additional lesions in 10 patients were seen by CE-IOUS. All lesions seen in B-scan could also be detected with CE-IOUS. Summary: This is the first study using contrast-enhanced ultrasound with high resolution linear probes for intraoperative detection of malignant liver lesions. Compared to preoperative imaging and also conventional IOUS more than 50% additional lesions were found leading to therapeutic consequences of patients. A recently started prospective study has to show whether these changes in the surgical or interventional therapy will influence morbidity, mortality and especially the recurrence rate. [ABSTRACT FROM AUTHOR]

Background: Contrast-enhanced ultrasonography (CEUS) represents a new diagnostic tool to localize pathological parathyroid glands. The aim of this study was to differentiate the capability of CEUS as first-line or complimentary modality for the detection of hyperfunctioning parathyroid glands. Methods: Sixty patients with pHPT were admitted to the University Hospital Regensburg between 8/2009 and 3/2011. Conventional and contrast-enhanced ultrasonography (CEUS) using a linear probe (6-9 MHz, LOGIQ E9/GE) was performed in all patients preoperatively. The sensitivity of CEUS was analyzed to determine its potential as first line or complimentary diagnostic procedure. Results: Using CEUS 98.3% of all pathological glands could be detected in the correct quadrant whereas conventional ultrasonography (70%) (p < 0.001) revealed less sensitivity. In all patients CEUS indicated a correct side localization of the hyperfunctioning parathyroid gland. The advantage of CEUS was the detection of the early dynamic on the capillary level immediately after contrast injection. Overall, CEUS permit minimally invasive video-assisted parathyroidectomy in 45 patients. 15 patients required conventional procedure due to concomitant goiter. All patients showed normal calcium and parathyroid hormone serum levels three months after surgery. Conclusions: CEUS represents a highly sensitive diagnostic modality for localization of pathologic parathyroid glands in patients with pHPT. Nevertheless, it can only be recommended as first-line diagnostic procedure in specialized clinical centers with experienced investigators. [ABSTRACT FROM AUTHOR]

Ultrasound-guided interventions (such as biopsies) of unclear lesions are indicated if microcirculatory changes indicate possible malignant lesions. These place high demands on the ultrasound device used. In order to potentially reduce the often associated high technical effort, the wireless ultrasound device Vscan AirTM was examined as a possible ultrasound device for the intervention biopsy.As part of an advanced training course on Computertomographie- and ultrasound-guided biopsy and ablation procedures, participants were asked about the image quality of the handheld device used by means of questionnaires. Various lesions were evaluated at a depth of 1.0 to 5.0 cm in an in vitro liver model. The image quality was evaluated independently before, during and after the intervention. The rating scale contained values from 0 (no assessment possible) to 5 (maximum high image quality). A high-end device was used as a reference.A total of 11 participants took part in the study (n = 4 male [36.4%], n = 7 female [63.6%]). A total of five tumor like lesions at different depths (1 cm, 2 cm, 3 cm, 4 cm, >4 cm) were assessed separately. In all cases, an adequate biopsy of the target lesion (1 cm in length, core filling 5 mm) was successful. From a depth of 3 cm, the image quality of the mobile device increasingly decreased, but the image quality of the high-end system was still not impaired. Compared to the high-end device, there was a highly significant difference in image quality from a depth of 3 cm (p < 0.01). Assessment by inexperienced examiners using a handheld device was adequately possible.Mobile interventional ultrasound represents a potential alternative for the biopsy of unclear tumorous lesions with microcirculatory disorders with limited depth localization. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The study aim was to investigate the use of a novel device, the Vscan Air™, for rapidly and effectively performing ultrasound in student teaching during the COVID-19 pandemic. MATERIAL AND METHODS: As part of the ultrasound practical course with integrated hands-on activity required by the regular medical curriculum, 100 medical students were instructed in the use of the Vscan Air™, including duplex mode. They then evaluated the quality of the ultrasound images obtained by the Vscan Air™ from previously selected organs. RESULTS: 100 students were interviewed (female n = 68, male n = 32; age >18 years n = 100). The rated image quality never fell below a mean of 3 for the examined organs and portal vein flow (liver 4,58; spleen 3,99; kidneys 4,29; aorta 4,16; Douglas/rectovesical space 4,14; portal vein 4,43; pancreas 3,53; Focused Assessment with Sonography for Trauma 4,38). Scores below 3 were found sporadically in ultrasounds of the spleen (n = 4), kidneys (n = 3), Douglas/rectovesical space (n = 2), and pancreas (n = 15). The liver was rated the lowest for 59 ratings. The portal vein was evaluated in 68 cases. The hepatic artery and hepatic veins could be also visualized in all 68 examinations. The aorta was evaluated in 62 cases. CONCLUSION: The Vscan Air™ technology offered adequate image quality and provided a new, fast and patient-oriented technique to support continuous ultrasound examinations and education of students, especially during a pandemic. Particularly noteworthy is the uncomplicated compliance with the required high level of hygiene. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To investigate the diagnostic accuracy of high-resolution ultrasound (HRU) for the detection of hepatic metastases of breast cancer in a humanized tumour mouse (HTM) using clinical standard technology. In addition, the efficiency of standard contrast-enhanced ultrasound (CEUS) [microbubbles of sulphur hexafluoride] and CEUS using a novel VEGFR2-targeted contrast agent [BR55®] was examined. METHODS: A total of 14 HTM were sonographically examined twice. In addition to a human immune system, the animals developed hepatic tumour lesions after intrahepatic injection of BT-474 breast cancer cells. Digital cine loops from the arterial phase (15–35 sec), the portal venous phase (35–90 sec) and the late phase (3–15 min) of the entire liver were analysed. Data were correlated to histopathology. RESULTS: After 9 months, half of the mice (7/14) revealed the development of hepatic breast cancer metastases. The detection limit was 1 mm tumour diameter. In particular, the use of targeted contrast media reduced the needed tumour diameter and helped to precisely classify tumour tissue. In 93% (13/14), the findings of ultrasound could be approved by histological examination by the pathologist. CONCLUSIONS: This study in HTM demonstrated the high feasibility of tumour specific contrast media and standard HRU contrast agents to detect early liver metastases. [ABSTRACT FROM AUTHOR]