Can single-phase dual-energy CT reliably identify adrenal adenomas?

PURPOSE: To evaluate whether single-phase dual-energy-CT-based attenuation measurements can reliably differentiate lipid-rich adrenal adenomas from malignant adrenal lesions. MATERIALS AND METHODS: We retrospectively identified 51 patients with adrenal masses who had undergone contrast-enhanced dual-energy-CT (140/100 or 140/80 kVp). Virtual non-contrast and colour-coded iodine images were generated, allowing for measurement of pre- and post-contrast density on a single-phase acquisition. Adrenal adenoma was diagnosed if density on virtual non-contrast images was ≤10 HU. Clinical follow-up, true non-contrast CT, PET/CT, in- and opposed-phase MRI, and histopathology served as the standard of reference. RESULTS: Based on the standard of reference, 46/57 (80.7%) adrenal masses were characterised as adenomas or other benign lesions; 9 malignant lesions were detected. Based on a cutoff value of 10 HU, virtual non-contrast images allowed for correct identification of adrenal adenomas in 33 of 46 (71%), whereas 13/46 (28%) adrenal adenomas were lipid poor with a density ≥10 HU. Based on the threshold of 10 HU on the virtual non-contrast images, the sensitivity, specificity, and accuracy for detection of benign adrenal lesions was 73%, 100%, and 81% respectively. CONCLUSION: Virtual non-contrast images derived from dual-energy-CT allow for accurate characterisation of lipid-rich adrenal adenomas and can help to avoid additional follow-up imaging. KEY POINTS: • Adrenal adenomas are a common lesion of the adrenal glands. • Differentiation of benign adrenal adenomas from malignant adrenal lesions is important. • Dual-energy based virtual non-contrast images help to evaluate patients with adrenal adenomas.

CT perfusion technique for assessment of early kidney allograft dysfunction: preliminary results.

OBJECTIVES: To assess the benefit of quantitative computed tomography (CT) perfusion for differentiating acute tubular necrosis (ATN) and acute rejection (AR) in kidney allografts. METHODS: Twenty-two patients with acute kidney allograft dysfunction caused by either AR (n = 6) or ATN (n = 16) were retrospectively included in the study. All patients initially underwent a multiphase CT angiography (CTA) protocol (12 phases, one phase every 3.5 s) covering the whole graft to exclude acute postoperative complications. Multiphase CT dataset and dedicated software were used to calculate renal blood flow. Renal biopsy or clinical course of disease served as the standard of reference. Mean effective radiation dose and mean amount of contrast media were calculated. RESULTS: Renal blood flow values were significantly lower (P = 0.001) in allografts undergoing AR (48.3 ± 21 ml/100 ml/min) compared with those with ATN (77.5 ± 21 ml/100 ml/min). No significant difference (P = 0.71) was observed regarding creatinine level with 5.65 ± 3.1 mg/dl in AR and 5.3 ± 1.9 mg/dl in ATN. The mean effective radiation dose of the CT perfusion protocol was 13.6 ± 5.2 mSv; the mean amount of contrast media applied was 34.5 ± 5.1 ml. All examinations were performed without complications. CONCLUSION: CT perfusion of kidney allografts may help to differentiate between ATN and rejection. KEY POINTS: • Quantitative CT perfusion of renal transplants is feasible. • CT perfusion could help to non-invasively differentiate AR from ATN. • CT perfusion might make some renal biopsies unnecessary.

[Ultrasound-guided image fusion with computed tomography and magnetic resonance imaging. Clinical utility for imaging and interventional diagnostics of hepatic lesions]. / Ultraschallgestützte Bildfusion mittels CT und MRT. Klinische Bedeutung für die bildgebende und interventionelle Diagnostik von Leberläsionen.

Abdominal ultrasound is often the first-line imaging modality for assessing focal liver lesions. Due to various new ultrasound techniques, such as image fusion, global positioning system (GPS) tracking and needle tracking guided biopsy, abdominal ultrasound now has great potential regarding detection, characterization and treatment of focal liver lesions. Furthermore, these new techniques will help to improve the clinical management of patients before and during interventional procedures. This article presents the principle and clinical impact of recently developed techniques in the field of ultrasound, e.g. image fusion, GPS tracking and needle tracking guided biopsy and discusses the results based on a feasibility study on 20 patients with focal hepatic lesions.

[Latest developments in ultrasound of the liver]. / Die letzten Entwicklungen beim Ultraschall der Leber.

Abdominal ultrasound (US) is often the first-line imaging modality used to assess focal liver lesions. Due to various new gray-scaled US techniques, such as tissue harmonic imaging (THI), spatial compounding technique and speckle reduction technique, as well as contrast-enhanced techniques, abdominal ultrasound nowadays has great potential regarding detection and characterization of focal liver lesions. Furthermore, image fusion with computed tomography (CT), magnetic resonance imaging (MRI) and 3D ultrasound will most likely help to improve clinical management before and after interventional procedures. This article illustrates the principles and clinical impact of recently developed techniques in the field of ultrasound.

[Contrast-enhanced ultrasound imaging of the carotid artery]. / Kontrastverstärkte Ultraschallbildgebung der A. carotis.

A conventional grey scale, Doppler sonography and color-coded Doppler ultrasound examination should be the first step in the diagnosis of the vessels supplying the brain and have a major impact in diagnostic imaging. This ultrasound examination allows the simultaneous acquisition of morphologic and hemodynamic information with high spatial and temporal resolution. Most of the pathological changes of the extracranial arteries can thus be reliably detected. Contrast-enhanced ultrasound (CEUS) is a promising new non-invasive method for the diagnosis and follow-up of complex carotid abnormalities. In addition to improving current carotid structural scans, CEUS has the potential to improve or provide additional information on carotid arterial diseases, such as the reliable differentiation between internal carotid artery (ICA) occlusion and pseudo-occlusion, improved visualization of in-stent stenosis, extracranial ICA aneurysms and carotid dissection.In this article the contribution of color-coded duplex ultrasound and CEUS in assessing various pathologies of the carotid artery will be addressed.

Automatic path proposal computation for CT-guided percutaneous liver biopsy.

PURPOSE: To evaluate feasibility of automatic software-based path proposals for CT-guided percutaneous biopsies. METHODS: Thirty-three patients (60 [Formula: see text] 12 years) referred for CT-guided biopsy of focal liver lesions were consecutively included. Pre-interventional CT and dedicated software (FraunhoferMeVis Pathfinder) were used for (semi)automatic segmentation of relevant structures. The software subsequently generated three path proposals in downward quality for CT-guided biopsy. Proposed needle paths were compared with consensus proposal of two experts (comparable, less suitable, not feasible). In case of comparable results, equivalent approach to software-based path proposal was used. Quality of segmentation process was evaluated (Likert scale, 1 [Formula: see text] best, 6 [Formula: see text] worst), and time for processing was registered. RESULTS: All biopsies were performed successfully without complications. In 91 % one of the three automatic path proposals was rated comparable to experts' proposal. None of the first proposals was rated not feasible, and 76 % were rated comparable to the experts' proposal. 7 % automatic path proposals were rated not feasible, all being second choice ([Formula: see text]) or third choice ([Formula: see text]). In 79 %, segmentation at least was good. Average total time for establishing automatic path proposal was 42 [Formula: see text] 9 s. CONCLUSION: Automatic software-based path proposal for CT-guided liver biopsies in the majority provides path proposals that are easy to establish and comparable to experts' insertion trajectories.

Comparison of portable ultrasound system and high end ultrasound system in detection of endoleaks.

PURPOSE: To compare the value of a portable ultrasound system and a high end ultrasound system in detection of endoleaks after EVAR. MATERIAL AND METHODS: In this retrospective study, a cohort of 25 patients underwent both standard examination using a portable ultrasound system (Philips VISIQ) and a second examination using a high end ultrasound system (Philips EPIQ 7). The examination included B-mode and color Doppler in detection of endoleaks. Additional the maximum diameter of the aneurysm was measured in two planes (right-left and ventral-dorsal). The gold standard was contrast-enhanced ultrasound (CEUS) in detection of endoleaks. RESULTS: 25 patients were included in the study. Patients were predominantly male (n = 23) with an average age of 73,30±7.82 years (range 54-85). Diameters of the treated aneurysms were in the right-left plane 5,32±1.88 cm and ventral-dorsal 4,99±1.78 cm using the high end system. Diameters of the treated aneurysms were in the right-left plane 5,30±1.82 cm and ventral-dorsal 4,87±1.74 cm using portable ultrasound system. In 80% of the cases CEUS could detect an endoleak. Whereas the high end system could detect in B-mode 40% and color Doppler 45% of the cases an endoleak. The portable system could detect in B-mode 30% and in color Doppler 35% of the cases an endoleak. On both systems in B-mode a false positive endoleak was found on the same patient. All high flow endoleaks, which needed intervention, could be detected on all systems. CONCLUSION: The high end ultrasound system does not seem to have an additional advantage in the measurement of the aneurysm diameter. Due to a higher resolution, more endoleaks could be detected in B-mode and color Doppler by using the high end system. The presence of small endoleaks could only be detected by using contrast enhanced ultrasound on an high end ultrasound system. High flow endoleaks could be reliable seen on both systems.

Value of high-resolution contrast-enhanced ultrasound in detection and characterisation of endoleaks after EVAR.

PURPOSE: To compare the value of high-resolution contrast-enhanced ultrasound in the detection and characterisation of endoleaks after EVAR. MATERIAL AND METHODS: In this retrospective study, a cohort of 80 patients underwent both standard examination using a curved array 5 MHz transducer and a second examination using a curved array 9 MHz transducer. The examination included B-mode, color Doppler and contrast-enhanced ultrasound using the Philips EPIQ 7 scanner. RESULTS: 80 patients were included in the study. CEUS was used as the preferred examination in determining the presence of an endoleak. The sensitivity and specificity for the detection of endoleak using the 5 MHz transducer was: CEUS (96.8%, 100%), Color Doppler (47.6%, 94.1%), B-mode (15.8%, 94.1%), while for the 9 MHz transducer: CEUS (100%, 100%), Color Doppler (39.7%, 94.1%), B-mode (23.8%, 24.1%). CONCLUSION: High resolution ultrasound (9 MHz) in detection and characterization of endoleaks after EVAR has some minor advantages in comparison to lower resolution ultrasound (5 MHz).

Dual-energy CT pulmonary angiography in patients with suspected pulmonary embolism: value for the detection and quantification of pulmonary venous congestion.

OBJECTIVE: To evaluate if vascular and pulmonary parenchymal enhancement values in dual-energy (DE) CT pulmonary angiography (CTPA) can suggest the diagnosis of pulmonary congestion. METHODS: DE-CTPA images of 90 out of 1321 patients negative for pulmonary embolism showed signs of congestive heart failure. We measured DE-derived pulmonary parenchymal [perfused blood volume (PBV)], pulmonary artery (PA) and left atrium (LA) enhancement values in these patients and in 142 control patients. Enhancement values were compared between the populations and correlated with serum values of B-type natriuretic peptide (BNP) and proBNP, where available. RESULTS: No significant difference of PBV but significant differences of mean PA and LA enhancement and individual enhancement differences (PA - LA) were found between the populations. PA - LA was higher in patients with elevated BNP and proBNP and was positively correlated with these values. Receiver operating characteristic analysis revealed a moderate discriminatory power of the PA - LA difference for the presence of cardiac biomarker elevations. CONCLUSION: PBV in DE-CTPA is not altered in patients with signs of congestive heart failure. However, differences in enhancement values in the pre- and post-pulmonary vessels were found in comparison with the control population. ADVANCES IN KNOWLEDGE: Altered pulmonary vascular haemodynamics in pulmonary venous congestion are not reflected in dual-energy-derived PBV maps. In the diagnosis of left heart failure in patients with chest pain and dyspnoea, density measurements in the pulmonary artery and in the left atrium in CTPA images may be a helpful diagnostic tool.

Ultrasound image fusion - clinical implementation and potential benefits for monitoring of renal transplants.

PURPOSE: To evaluate the feasibility of US image fusion in the clinical routine and to discuss potential benefits for follow-up after renal transplantation. MATERIALS AND METHODS: 15 patients with a renal transplant were prospectively included in the study. For all of them, a previously performed CT- or MRI-scan covering the renal transplant was available. Each patient was investigated using ultrasound image fusion. Time needed for sucessful implementation of image fusion was registered. Subsequently, quality of image fusion was assessed by two experienced radiologists (10 and 5 years of experience) in consensus using a subjective 5 point rank scale (1 = best). RESULTS: Image fusion was successfully performed in all patients. Time needed for setup of image fusion varied from 45-120 sec (85 ± 5 sec). The score for quality of US image fusion was 1.9 ± 0.7. CONCLUSION: Assessment of renal transplants using US image fusion is feasible and provides several potential benefits for the follow-up of renal transplants.

Image fusion in the management of thermal tumor ablation of the liver.

PURPOSE: The purpose of this study was to evaluate whether image fusion with contrast enhanced ultrasound (CEUS) and CT is effective in the pre-, intra- and post-interventional management of liver lesions during microwave or radiofrequency ablation. METHODS AND MATERIALS: Fifteen patients with a single hepatocellular carcinoma (HCC) up to 3 cm diameter, identified on both contrast-enhanced CT (Siemens Somatom Definition AS and Definition Edge, Siemens Healthcare, Erlangen, Germany) and ultrasound (Siemens ACUSON S2000™ or S3000™, Siemens Healthcare, Erlangen, Germany) were retrospectively enrolled between July 2011 and May 2012. Either automatic registration or plane match registration was chosen on CT and ultrasound for the pre-, intra- and postinterventional management of all treated liver lesions during microwave or radiofrequency ablation. Using conventional ultrasound B-mode, CEUS and image fusion including B-mode and CEUS the detectability of the liver lesions was evaluated semi-quantitatively by comparing the image sequences in a consensus reading. Eight patients underwent radiofrequency ablation and seven patients underwent microwave ablation. RESULTS: All patients were examined using all diagnostic ultrasound tools of the study. The results show that the procedure is easy and convenient to perform, as well as efficient. The co-registration procedure took approximately 5 to 10 minutes depending on the amount of DICOM volume-data and the habitus of the patient. The results show that the use of image fusion with CT and contrast-enhanced ultrasound could improve the diagnostic assessment capabilities in comparison to the examination without image fusion in the pre-, intra- and postinterventional management of malignant liver lesions during thermal ablation. CONCLUSION: Percutaneous thermal ablation guided by contrast-enhanced ultrasound and image fusion seems to be an efficient approach for malignant liver lesions especially if these are not clearly demarcated by B-mode. The use of the image fusion technique in the pre-, intra- and postinterventional management can increase operator confidence, the accuracy of the procedure, and technical success in real time.

Multimodality imaging using ultrasound image fusion in renal lesions.

OBJECTIVES: To assess the benefit of ultrasound (US) image fusion in the identifiability and assessment of the dignity of renal lesions. MATERIALS AND METHODS: 25 patients with 29 renal lesions were investigated using standard US and CEUS (contrast enhanced US) with image fusion (CT or MRI). Identifiability and assessment of dignity was evaluated using cross-sectional images and US separately as well as using both US-techniques with additional image fusion. The respective modality was rated by two experienced radiologists (10 and 5 years of experience) using a (subjective) 5 point rank scale (1 = best). RESULTS: Using CEUS, image fusion resulted in improved identifiability (score: 1.1 ± 0.4) and improved assessment of dignity (score 1.0 ± 0) of renal lesions than using cross sectional images (score 1.8 ± 1.2 and 3.8 ± 1.2 respectively) separately. CONCLUSION: Image fusion improved the identifiability and the assessment of the dignity of renal lesions compared to using the respective modalities separately.

Improved carotid atherosclerotic plaques imaging with contrast-enhanced ultrasound (CEUS).

PURPOSE: To evaluate neovascularisation within carotid atherosclerotic plaques with contrast enhanced ultrasound. METHODS: We used contrast-enhanced ultrasound to examine 33 patients with carotid atherosclerotic plaques. Plaque size and echogenicity were analyzed and we correlated neovascularization within the plaques. RESULTS: There were 41 atherosclerotic plaques, 27 plaques enhanced after the injection of a contrast agent. Among the group of enhancing plaques we found 8 soft- and 19 mixed plaques. The overall thickness ranging in enhanced plaques was from 1.8 to 4.6 mm. In all cases the contrast uptake in the plaques was later than in the carotid artery. Among the 14 unenhanced atherosclerotic plaques, 4 plaques presented as hard plaques, three calcified plaques, two soft plaques and five presented as mixed plaques. The overall thickness ranging in unenhanced plaques was from 1.7 to 6 mm. CONCLUSION: Contrast-enhanced ultrasound allows the non invasive, dynamic evaluation of neovascularisation within carotid plaques.

Duplex and contrast enhanced ultrasound (CEUS) in evaluation of in-stent restenosis after carotid stenting.

PURPOSE: The aim of the study was to evaluate whether contrast enhanced ultrasound (CEUS) can improve the visualization of in-stent restenosis after carotid stenting of the internal carotid artery (ICA) in comparison to color-coded duplex sonography (CCDS) and power Doppler. MATERIAL AND METHODS: The study included the follow up of thirty patients after carotid artery stenting (CAS). Intrastenotic flow detection and lengths of in-stent restenosis were the main criteria. A high-end ultrasound machine (Siemens, ACUSON, Sequoia or S2000) with a multi-frequency linear 9 MHz or 15 MHz transducer was used to carry out contrast-enhanced ultrasound with SonoVue. In cases of treatment of a high degree in-stent stenosis intra-arterial digital subtraction angiography (DSA) was used. RESULTS: All patients were examined using all diagnostic ultrasound tools of the study. In five patients (17%) an in-stent restenosis of the internal carotid artery (ICA) was found. Two patients need a reintervention. The results show that the contrast enhanced ultrasound could improve the diagnostic assessment capabilities in comparison to CCDS and power Doppler for patients with in-stent restenosis after carotid stenting of the ICA. CONCLUSION: Contrast enhanced ultrasound is a reliable method for the evaluation of in-stent restenosis after carotid stenting of the ICA. CEUS provides a reduction in intrastenotic flow artefacts, resulting in better visualisation and detection of the complete length of the stenosis in comparison with CCDS and power Doppler. In order to elucidate hemodynamic changes, additional Doppler examinations are still necessary.

Imaging of carotid arterial diseases with contrast-enhanced ultrasound (CEUS).

Carotid duplex ultrasound is the standard of care for the initial diagnosis of carotid artery bifurcation diseases. But in difficult examinations, carotid abnormalities are commonly encountered and may represent a diagnostic challenge in patients with clinical symptoms as well as in the follow up after carotid endarterectomy or carotid artery stenting. Contrast enhanced ultrasound (CEUS) with low mechanical index (low MI) is a promising new method in the diagnosis and follow up of pathological carotid diseases. Unlike most contrast agents used for magnetic resonance imaging or computed tomography, the microbubbles used in CEUS with SonoVue(®) remain within the vascular space and hence can be used to study vascular disease. In addition to improving current carotid structural scans, CEUS has potential to improve or add extra information on carotid arterial diseases. This review describes the current carotid duplex ultrasound examination and compares the pathological findings with CEUS.

Optimized contrast volume for dynamic CT angiography in renal transplant patients using a multiphase CT protocol.

OBJECTIVES: To study the feasibility of an optimized multiphase renal-CT-angiography (MP-CTA) protocol in patients with history of renal transplantation compared with Doppler-ultrasound (DUS). METHODS: 36 Patients underwent both DUS and time-resolved, MP-CTA (12 phases), with a mean contrast-volume of 34.4±5.1 ml. Quality of MP-CTA was assessed quantitatively (vascular attenuation) and qualitatively (grades 1-4, 1=best). For the assessment of clinical value of MP-CTA, cases were grouped into normal, macrovascular (arterial/venous) and microvascular complications (parenchymal perfusion defect). DUS served as the standard of reference. RESULTS: Using the best of 12 phases in each patient, optimal attenuation was 353±111 HU, 337±98 HU and 164±51 HU in the iliac arteries, renal arteries, and renal veins, respectively. Mean image quality was 1.1±0.3 (n=36) and 2.1±0.6 (n=30) for the transplant renal arteries and veins, respectively. Six renal veins were non-diagnostic in MP-CTA. In 36 patients, MP-CTA showed 13 vascular complications and 10 parenchymal perfusion defects. DUS was not assessable in eight patients. Overall, MP-CTA showed 15 cases with pathology (42%) not identifiable with DUS. The mean effective radiation dose of the MP-CTA protocol was 13.5±5.2 mSv. CONCLUSION: MP-CTA can be sufficiently performed with reduced contrast volume at reasonable radiation dose in renal transplant patients, providing substantially higher diagnostic yield than DUS.

Benefit of contrast enhanced ultrasound for detection of ischaemic lesions and arterio venous fistulas in renal transplants - a feasibility study.

PURPOSE: To evaluate the benefit of CEUS (contrast enhanced ultrasound) regarding depiction of ischaemic lesions and AVFs (arterio venous fistula) in renal transplants compared to standard ultrasound (US) (grey-scale and color Doppler). MATERIALS AND METHODS: In this study 22 patients suspected of having acute vascular complication after renal transplantation were investigated using standard ultrasound (grey-scale US and color Doppler US) and CEUS, respectively. Validity of the respective US-techniques regarding depiction of ischaemic lesions and AVF was compared. Dynamic CTA (computed tomography angiography) served as the standard of reference. RESULTS: In 10 renal transplants arterial embolism associated with kidney infarctions were observed. Very good correlation to dynamic CTA was yielded using CEUS, whereas grey scale US and color Doppler US was limited in the accurate depiction of renal infarctions. Additionally CEUS was superior in displaying arteriovenous fistulas compared to standard US. CONCLUSION: CEUS as a fast and bedside available imaging modality not associated with dose exposure or renal toxicity facilitates improved detection of ischaemic lesions and AVFs compared to standard US and thus should be considered for short term follow up of renal transplants.

Improving the follow up after EVAR by using ultrasound image fusion of CEUS and MS-CT.

PURPOSE: To evaluate whether the image fusion with contrast enhanced ultrasound (CEUS) and CT affects the diagnosis of endoleaks in unclear cases. METHODS AND MATERIALS: 35 patients with follow-up examinations after endovascular aneurysm repair (EVAR) were included in this retrospective study. Mean patient age was 73 years (range 54-83 y). B-scan, colour doppler and CEUS (1.2 ml SonoVue®, Bracco Imaging Germany) were performed in all patients by an experienced examiner using two different high-end ultrasound system (Siemens ACUSON S2000™, Siemens Healthcare, Erlangen, Germany or Logic E9, GE Healthcare, Milwaukee,WI, USA) with a multifrequency curved array transducer. The examiner was initially blinded to the CT results. Additional image fusion with CT-angiography (CTA) was then performed. The ultrasound examinations were later read by two blinded unbiased investigators with more than five years of clinical ultrasound in consensus. RESULTS: All patients were examined using all diagnostic ultrasound tools of the study. The results show that image fusion is easy and convenient to perform. Conventional ultrasound examination with B-scan and colour Doppler examination detected one Type I and one Type II endoleak, contrast enhanced ultrasound detected one Type I and three Type II endoleaks after EVAR whereas CTA depicted one Type I and two Type II endoleaks. Ultrasound image fusion with CT-angiography confirmed one Type I and three Type II endoleaks. CONCLUSION: In comparison to conventional ultrasound and CTA the use of CEUS improved the visualization and classification of endoleaks. CEUS shows even small blood flow which can be depicted due to the real time imaging of endoleaks. In unclear cases additional ultrasound image fusion with CEUS and CT angiography improves the visualisation of small endoleaks and this may cause a change in the follow-up interval. CEUS is a good alternative to CT in the detection and follow-up of endoleaks, especially in patients with contraindications to CT contrast agents due to allergies or renal failure, enabling reduced additional costs and exposure to radiation.

Improved visualization of renal lesions using three-dimensional ultrasound--a feasibility study.

PURPOSE: To evaluate the potential benefit of three-dimensional ultrasound in the assessment of renal lesions. MATERIALS AND METHODS: 21 patients with unclear renal findings were prospectively included in the study. Every patient was examined using two-dimensional (2D) ultrasound (US), X-plane technique (simultaneous display of main image and second image at a plane at right angles to the first), and real time three-dimensional (3D) US. The imaging model used were standard gray scale-, duplex- and contrast-enhanced ultrasound (CEUS). All acquisitions were compared to each other with regard to image quality and identifiability of renal lesions. Additionally, when using the X-plane technique the quality of the first and the second image were analysed separately. The assessment was done using a subjective 6 point scale (1 = best). RESULTS: All acquisitions were successfully performed and no patient had to be excluded. Image quality of real time 3D-US (score: 2.4 ± 0.73) was slightly inferior to 2D-US and X-plane technique (main image) with a score of 2.2 ± 0.43 and 2.2 ± 0.5, respectively. The image quality of second image in the X-plane mode -due to a lower spatial resolution- was lower with a score of 3.2 ± 0.5. Real time 3D-US and X-plane technique allowed for better identifiability (score: 1.4 ± 0.59 and 1.9 ± 0.53) of renal lesions compared to 2D-US (score: 2.5 ± 0.6). The most marked difference was observed between the simultaneous use of real time 3D-US and X-plane technique versus 2D-US in case of renal cell carcinoma, especially with regard to extra-capsular tumor extension (score: 1.6 ± 0.52, 1.8 ± 0.71, and 3.0 ± 0.52, respectively). CONCLUSION: Assessment of renal lesions using real time 3D-US is feasible and improves the identifiability of renal lesions.

Diagnosis, therapy monitoring and follow up of renal artery pseudoaneurysm with contrast-enhanced ultrasound in three cases.

PURPOSE: We describe the presentation of renal artery pseudoaneurysm (RAP) in different imaging modalities (CT, DSA, standard US, contrast enhanced ultrasound (CEUS)). In particular the benefit of CEUS with regards to therapy monitoring and follow up care shall be highlighted. MATERIALS AND METHODS: Three patients with renal artery pseudoaneurysm after renal surgery were investigated with CT and/or US (grey-scaled US, color duplex US, CEUS), respectively. The therapy (angiography-coiling) was monitored using contrast-enhanced ultrasound. RESULTS: Accurate diagnosis of RAP in our study was yielded using color duplex US and CEUS. CEUS was very practical for therapy monitoring of coil embolization with the potential of shortening the invasive DSA. Thus, CEUS has potential of radiation dose reduction and the potential of saving coils with the result of cost reduction. CONCLUSION: CEUS is an appropriate approach for monitoring coil embolization of RAP.