[Imaging of neuroendocrine tumors of the gastrointestinal tract : Value of (hybrid) imaging diagnostics in radiology]. / Bildgebung von neuroendokrinen Tumoren des Gastrointestinaltrakts : Bedeutung der (hybriden) bildgebenden Diagnostik in der Radiologie.

CLINICAL/METHODICAL ISSUE: Neuroendocrine tumors (NET) represent a heterogeneous group of rare tumors that predominantly arise in the gastrointestinal tract. At the time of initial diagnosis, the NET has already spread locoregionally in about half of the patients, and 27% of patients have already developed distant metastases. Since this plays a crucial role in therapy planning, accurate diagnostic imaging is important. STANDARD RADIOLOGICAL METHODS: Due to its high temporal and spatial resolution (multiphasic including arterial phase), computed tomography (CT) plays a decisive role in primary staging and follow-up care, while magnetic resonance imaging (MRI) with its excellent soft tissue contrast offers advantages in the assessment of parenchymal organs in the upper abdomen. METHODICAL INNOVATIONS: Somatostatin receptor (SSR) positron emission tomography (PET) provides additional functional information that not only helps to detect the primary tumor and distant metastases, but also has a significant influence on therapeutic management in a theranostic approach. PERFORMANCE: Hybrid imaging using SSR-PET/CT has proven to be particularly effective in the detection of NET. Compared to conventional imaging, it provides additional information in 68% of patients, which has a significant impact on clinical management. ACHIEVEMENTS: Imaging of NET requires the combined use of various methods such as ultrasound, CT, MRI, and PET/CT to enable accurate diagnosis and effective treatment planning. PRACTICAL RECOMMENDATIONS: SSR-PET/CT is a valuable tool for the accurate staging of neuroendocrine tumors of the gastrointestinal tract, especially with small metastases, while MRI with hepatocyte-specific contrast agent and diffusion-weighted imaging is useful for the specific assessment of liver metastases.

Validation of the standardization framework SSTR-RADS 1.0 for neuroendocrine tumors using the novel SSTR­targeting peptide [18F]SiTATE.

OBJECTIVES: Somatostatin receptor positron emission tomography/computed tomography (SSTR-PET/CT) using [68Ga]-labeled tracers is a widely used imaging modality for neuroendocrine tumors (NET). Recently, [18F]SiTATE, a SiFAlin tagged [Tyr3]-octreotate (TATE) PET tracer, has shown great potential due to favorable clinical characteristics. We aimed to evaluate the reproducibility of Somatostatin Receptor-Reporting and Data System 1.0 (SSTR-RADS 1.0) for structured interpretation and treatment planning of NET using [18F]SiTATE. METHODS: Four readers assessed [18F]SiTATE-PET/CT of 95 patients according to the SSTR-RADS 1.0 criteria at two different time points. Each reader evaluated up to five target lesions per scan. The overall scan score and the decision on peptide receptor radionuclide therapy (PRRT) were considered. Inter- and intra-reader agreement was determined using the intraclass correlation coefficient (ICC). RESULTS: The ICC analysis on the inter-reader agreement using SSTR-RADS 1.0 for identical target lesions (ICC ≥ 85%), overall scan score (ICC ≥ 90%), and the decision to recommend PRRT (ICC ≥ 85%) showed excellent agreement. However, significant differences were observed in recommending PRRT among experienced readers (ER) (p = 0.020) and inexperienced readers (IR) (p = 0.004). Compartment-based analysis demonstrated good to excellent inter-reader agreement for most organs (ICC ≥ 74%), except for lymph nodes (ICC ≥ 53%). CONCLUSION: SSTR-RADS 1.0 represents a highly reproducible and consistent framework system for stratifying SSTR-targeted PET/CT scans, even using the novel SSTR-ligand [18F]SiTATE. Some inter-reader variability was observed regarding the evaluation of uptake intensity prior to PRRT as well as compartment scoring of lymph nodes, indicating that those categories require special attention during further clinical validation and might be refined in a future SSTR-RADS version 1.1. CLINICAL RELEVANCE STATEMENT: SSTR-RADS 1.0 is a consistent framework for categorizing somatostatin receptor-targeted PET/CT scans when using [18F]SiTATE. The framework serves as a valuable tool for facilitating and improving the management of patients with NET. KEY POINTS: SSTR-RADS 1.0 is a valuable tool for managing patients with NET. SSTR-RADS 1.0 categorizes patients with showing strong agreement across diverse reader expertise. As an alternative to [68Ga]-labeled PET/CT in neuroendocrine tumor imaging, SSTR-RADS 1.0 reliably classifies [18F]SiTATE-PET/CT.

Diagnostic accuracy of SSR-PET/CT compared to histopathology in the identification of liver metastases from well-differentiated neuroendocrine tumors.

BACKGROUND: Histopathology is the reference standard for diagnosing liver metastases of neuroendocrine tumors (NETs). Somatostatin receptor-positron emission tomography / computed tomography (SSR-PET/CT) has emerged as a promising non-invasive imaging modality for staging NETs. We aimed to assess the diagnostic accuracy of SSR-PET/CT in the identification of liver metastases in patients with proven NETs compared to histopathology. METHODS: Histopathologic reports of 139 resected or biopsied liver lesions of patients with known NET were correlated with matching SSR-PET/CTs and the positive/negative predictive value (PPV/NPV), sensitivity, specificity, and diagnostic accuracy of SSR-PET/CT were evaluated. PET/CT reading was performed by one expert reader blinded to histopathology and clinical data. RESULTS: 133 of 139 (95.7%) liver lesions showed malignant SSR-uptake in PET/CT while initial histopathology reported on 'liver metastases of NET´ in 127 (91.4%) cases, giving a PPV of 91.0%. Re-biopsy of the initially histopathologically negative lesions (reference standard) nevertheless diagnosed 'liver metastases of NET' in 6 cases, improving the PPV of PET/CT to 95.5%. Reasons for initial false-negative histopathology were inadequate sampling in the sense of non-target biopsies. The 6 (4.3%) SSR-negative lesions were all G2 NETs with a Ki-67 between 2-15%. CONCLUSION: SSR-PET/CT is a highly accurate imaging modality for the diagnosis of liver metastases in patients with proven NETs. However, we found that due to the well-known tumor heterogeneity of NETs, specifically in G2 NETs approximately 4-5% are SSR-negative and may require additional imaging with [18F]FDG PET/CT.

Cost-effectiveness of stress CTP versus CTA in detecting obstructive CAD or in-stent restenosis in stented patients.

OBJECTIVES: The aim of this retrospective study was to determine cost-effectiveness of stress myocardial CT perfusion (CTP), coronary CT angiography (CTA), and the combination of both in suspected obstructive coronary artery disease (CAD) or in-stent restenosis (ISR) in patients with previous coronary stent implantation. METHODS: A decision model based on Markov simulations estimated lifetime costs and quality-adjusted life years (QALYs) associated with CTA, CTP, and CTA + CTP. Model input parameters were obtained from published literature. Probabilistic sensitivity analysis was performed to evaluate overall model uncertainty. A single-variable deterministic sensitivity analysis evaluated the sensitivity of the results to plausible variations in model inputs. Cost-effectiveness was assessed based on a cost-effectiveness threshold of $100,000 per QALY. RESULTS: In the base-case scenario with willingness to pay of $100,000 per QALY, CTA resulted in total costs of $47,013.87 and an expected effectiveness of 6.84 QALYs, whereas CTP resulted in total costs of $46,758.83 with 6.93 QALYs. CTA + CTP reached costs of $47,455.63 with 6.85 QALYs. Therefore, strategies CTA and CTA + CTP were dominated by CTP in the base-case scenario. Deterministic sensitivity analysis demonstrated robustness of the model to variations of diagnostic efficacy parameters and costs in a broad range. CTP was cost-effective in the majority of iterations in the probabilistic sensitivity analysis as compared with CTA. CONCLUSIONS: CTP is cost-effective for the detection of obstructive CAD or ISR in patients with previous stenting and therefore should be considered a feasible approach in daily clinical practice. KEY POINTS: • CTP provides added diagnostic value in patients with previous coronary stents. • CTP is a cost-effective method for the detection of obstructive CAD or ISR in patients with previous stenting.

The diagnostic value of contrast-enhanced ultrasound (CEUS) for assessing hepatocellular carcinoma compared to histopathology; a retrospective single-center analysis of 119 patients1.

BACKGROUND: HCC as the 6th most common tumor entity with the fourth highest mortality and an increasing prevalence especially due to today's lifestyle acquires a high attention in the clinical setting. Beside CECT and CEMRI, CEUS depicts a dynamic, low-risk and radiation free imaging method that finds its use mainly in screening and active surveillance programs. PURPOSE: The aim of the retrospective study was to evaluate the diagnostic value of CEUS in correlation to pathologic findings. MATERIALS AND METHODS: Between 2004 and 2018 a total number of 119 patients were included in this retrospective single-center study. Every patient underwent CEUS in addition to a native B-mode and Color-Doppler scan. After given informed consent SonoVue® (Bracco, Milan, Italy), a second-generation blood-pool agent, was used as contrast medium. Every examination was performed and interpreted by a single experienced radiologist (EFSUMB level 3). A low mechanical index (MI) of <0,2 was chosen to obtain a good imaging quality. RESULTS: All 119 included patients received CEUS followed by a liver biopsy for inter-modality comparison. In correlation to the pathology results, CEUS showed a diagnostic sensitivity of 96,6%, a specificity of 63,9%, a PPV of 86,7% and a NPV of 88,5% by detecting liver lesions suspicious for HCC. According to the Cohen's Kappa coefficient (k = 0,659) CEUS shows a strong inter-modality agreement in comparison to the histopathological finding. CONCLUSION: With a high sensitivity and a strong cross-modality comparability to histopathology, the CEUS is highly effective in the detection of suspicious HCC lesions.

The diagnostic performance of contrast-enhanced ultrasound (CEUS) for evaluating hepatocellular carcinoma (HCC) juxtaposed to MRI findings; a retrospective single-center analysis of 292 patients.

BACKGROUND: HCC is the most frequent primary liver cancer entity. Major risk factors comprise chronic HBC and HCV infections, ALD or NAFLD. Apart from the anamnesis, the clinical examination and serologic analysis, an essential part of the diagnostic HCC work-up is due to imaging findings from sonography, CT or MRI scans. HCC lesions feature a distinct vascularization pattern: hyperenhancement during early arterial and hypoenhancement/wash-out during portal venous or delayed phases. CEUS facilitates dynamic assessment of microperfusion patterns of suspicious liver lesions. PURPOSE: The purpose of the present retrospective single-center study was to determine the diagnostic value of CEUS for assessing HCC by comparison with findings from MRI scans. MATERIALS AND METHODS: Between 2004-2018 292 patients with suspicious liver lesions underwent CEUS and MRI. All patients underwent native B-mode, Color Doppler and CEUS after given informed consent. The applied contrast agent was a second-generation blood pool agent (SonoVue®, Bracco, Milan, Italy). Every CEUS examination was performed and interpreted by a single experienced radiologist (EFSUMB Level 3). RESULTS: CEUS was performed on all included patients without occurrence of any adverse effects. CEUS showed a sensitivity of 96%, a specificity of 91%, a PPV of 95% and a NPV of 94% for analyzing HCC in comparison with MRI as the diagnostic gold standard. CONCLUSION: With a distinguished safety profile CEUS shows a high diagnostic accuracy in assessing HCC compared to corresponding results from MRI scans.

Contrast-enhanced ultrasound (CEUS) in the diagnostic evaluation of popliteal artery aneurysms, a single-center study.

BACKGROUND: Popliteal artery aneurysms (PAA) are the most common peripheral artery aneurysms. Most common cause is arteriosclerosis. Acute thromboembolic limb ischemia and rupture of the PAA depict severe complications. Diagnostic tools for identifying PAAs are (Doppler) ultrasound, CT/MR angiography and DSA. PURPOSE: The aim of the present retrospective single-center study is to assess the application and safety of CEUS for assessing untreated and treated PAAs. MATERIALS AND METHODS: 13 patients were included in this study on whom CEUS was performed between 2007-2016. CEUS examinations were performed and interpreted by an experienced single radiologist (EFSUMB Level 3). RESULTS: CEUS allowed for the detection of PAAs in all cases. CEUS allowed for detection of partial thrombosis of PAA in 7/8 of untreated patients, proper exclusion of PAA upon femoro-popliteal bypass in 3 patients, incomplete exclusion of PAA upon femoro-popliteal bypass in 1 patient and ruling out of in-stent stenosis in 1 patient. CONCLUSION: CEUS is a useful and safe tool for in real-time evaluation of PAAs in the pre-/post-treatment status. In addition to conventional (Doppler) ultrasound and as an alternative tool to more elaborate imaging modalities, CEUS might be integrated in the future diagnostic work-up and follow-up of PAA patients.

Long-term study analysis of contrast-enhanced ultrasound in the diagnosis of focal nodular hyperplasia.

BACKGROUND: Focal nodular hyperplasia (FNH) is a hyperplastic mass of vascular abnormality and the second most common benign liver lesion. It can be discovered incidentally or during a surveillance examination in patients at risk for hepatic malignancy, mostly by conventional ultrasound. CEUS has been used as an additional alternative method for the rapid diagnosis of FNH. However, none of the previous studies compared the diagnostic performance of CEUS to MRI retrospectively in a 10-year observation. OBJECTIVE: The aim of this long-term retrospective study is to assess the diagnostic performance of CEUS in the imaging of FNH and compare the results to MRI. MATERIAL AND METHODS: A single experienced physician performed CEUS examinations in 244 patients between 2009 and 2019 with suspected focal nodular hyperplasia after conventional ultrasound. A second-generation blood pool agent (SonoVue®, Bracco, Milan, Italy) was administered. Additional dynamic MRI with contrast agent was performed in a subgroup of 95 patients. RESULTS: Out of 244 patients, FNH could be displayed in 221 patients on CEUS. A subgroup of 95 patients had CEUS examinations and CEMRI for diagnosis comparison. In comparison with CEMRI, CEUS presented a sensitivity of 97%, a specificity of 76%, a positive predictive value of 93% and a negative predictive value of 89%. CONCLUSION: CEUS is a safe and feasible approach that assess the diagnosis of focal nodular hyperplasia equally to MRI. The focal lesion enhancement can be depicted in real-time in the arterial, venous and late phase facilitating the prompt diagnosis.

[Neuroendocrine tumors of the stomach, duodenum and pancreas : Value of (hybrid) radiological diagnostics]. / Neuroendokrine Tumoren von Magen, Duodenum und Pankreas : Stellenwert der (hybriden) radiologischen Diagnostik.

CLINICAL/METHODICAL ISSUE: Neuroendocrine tumors (NET) of the stomach, duodenum and pancreas are rare tumors with a low incidence but the exact tumor localization and staging diagnostics are of critical importance for further planning of treatment. STANDARD RADIOLOGICAL METHODS: Standard primary diagnostic methods include multimodal imaging with computed tomography (CT) and magnetic resonance imaging (MRI) but in 20-50% of the cases the localization of the primary tumor cannot be identified. METHODICAL INNOVATIONS: Modern hybrid imaging procedures combine radiological procedures and functional imaging, e.g. using somatostatin receptor (SSR) positron emission tomography CT (PET)/CT imaging. For the exact diagnostics of the primary tumor and distant metastases morphological and functional aspects can be combined for targeted diagnostics. For primary tumor staging a sensitivity of 80.0% and a specificity of 88.4% are given in the literature. PERFORMANCE: The application of SSR PET/CT led to a change in patient management in 44% of all cases according to a recently published meta-analysis and therefore had a significant influence on the further procedure. ASSESSMENT: The use of SSR PET/CT can provide critical information for further treatment and can lead to a significant change in treatment management in a relevant proportion of patients. PRACTICAL RECOMMENDATIONS: Radiological imaging diagnostics and in particular hybrid functional imaging procedures using PET/CT will become increasingly more relevant for the diagnostics, treatment and follow-up of NET patients.

Performance of contrast-enhanced ultrasound (CEUS) compared to MRI in the diagnostic of gallbladder diseases.

BACKGROUND: Conventional ultrasound and MRI are very important techniques for the detection of gallbladder alterations. In the past years, studies showed that the additional use of contrast media to the conventional ultrasound allows the early depiction of pathological microvessels and their flow elucidating suspect findings stipulating the prompt therapy approach. OBJECTIVE: The study aims to evaluate the performance of CEUS in gallbladder diseases and compare it to MR imaging using histopathological findings as a gold standard. MATERIAL AND METHODS: The retrospective mono-center study analysed 18 patients with gallbladder alterations between 2009 and 2017. All patients underwent CEUS and MRI examinations and all results were confirmed in the pathology. CEUS images were performed and interpreted by a single experienced physician. RESULTS: CEUS imaging results compared to MR imaging of the gallbladder demonstrated a sensitivity of 100%, specificity of 93%, a positive predictive value of 67% and a negative predictive value of 100%. CONCLUSION: CEUS enables the depiction and characterization of important vascularization's patterns facilitating the early differentiation between malignant and benign findings. In this study, CEUS displayed a better diagnostic accuracy than MRI proving to be a valuable additional tool to the established imaging modalities.

Single-center study: The diagnostic performance of contrast-enhanced ultrasound (CEUS) for assessing focal splenic lesions compared to CT and MRI.

BACKGROUND: Frequently focal splenic lesions (FSL) - cysts, hemangioma, hamartoma, metastases or infarction amongst others - are incidentally found within the scope of the sonographic examination of the abdomen. By using native B-mode and Color Doppler the underlying entity often is not elucidated. Thus, more elaborate imaging modalities like CT and MRI scans with their associated risks are used to clarify the entity of FSL. PURPOSE: The aim of the present retrospective single-center study is to evaluate the diagnostic performance of CEUS examination for assessing splenic focal lesions by comparison with findings from CT and MRI scans. MATERIALS AND METHODS: Between 2010-2018 46 patients were included in the study. All patients underwent native B-mode, Color Doppler and CEUS after given informed consent. The applied contrast agent was a second-generation blood pool agent (SonoVue®, Bracco, Milan, Italy). CEUS examinations were performed and interpreted by a single experienced radiologist (EFSUMB Level 3). RESULTS: All patients were examined without occurrence of any side effects. In total, 53 FSL were investigated (9% traumatic vs. 91% non-traumatic). Compared to CT, CEUS showed a sensitivity, specificity, PPV, NPV of 100% for assessing infarction, hematoma, hamartoma, cystic and malignant lesions. In comparison with MRI, CEUS presented a sensitivity, specificity, PPV, NPV of 100% for evaluating pseudolesions, hemangioma, hamartoma, cystic and malignant lesions. CONCLUSION: With an excellent safety profile CEUS shows an equipollent diagnostic performance for differentiating FSL compared to CT and MRI scans.

[Modern sonographic imaging of abdominal neuroendocrine tumors]. / Moderne sonographische Bildgebung bei neuroendokrinen Tumoren des Abdomens.

BACKGROUND: Radiological and nuclear medical diagnostics play an important role in the work-up of patients with gastroenteropancreatic neuroendocrine tumors (GEP-NET). The sonographic examination, including contrast-enhanced examination, depicts an initial imaging modality to screen for NET. This report describes the sonomorphological behavior of ileal and pancreatic NET as well as hepatic metastases from NET. CLINICAL/METHODICAL ISSUE: Sonographic evaluation of NET of the small intestine, pancreas and neuroendocrine hepatic metastases. STANDARD RADIOLOGICAL METHODS: Contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI), unenhanced ultrasonography. METHODICAL INNOVATIONS: Contrast-enhanced ultrasound (CEUS). PERFORMANCE: CEUS supports unenhanced ultrasound in the detection of NET and the differential diagnosis of unclear lesions, and is more sensitive for liver metastases (sensitivity according to the literature, 99% vs. 68%) PRACTICAL RECOMMENDATIONS: CEUS allows initial evaluation of NET and differentiation of benign vs. malignant lesions. Nevertheless, CEUS cannot replace more elaborate imaging modalities like CT or MRI for thorough staging examinations.

Contrast-enhanced ultrasound (CEUS) for the evaluation of gallbladder diseases in comparison to cross-sectional imaging modalities and histopathological results.

BACKGROUND: The first method of choice for gallbladder alteration detection is the conventional ultrasound. Due to some imaging limitations, contrast-enhanced ultrasound (CEUS) has been widely used in the last years. CEUS is an additional modality that is able to depict microvessels flow and elucidate suspicious findings. OBJECTIVE: The aim of this retrospective mono-center analysis study is to evaluate the performance of CEUS in gallbladder diseases and compare it to cross-sectional imaging modalities and histopathological results as gold standard. METHODS: The retrospective study analysed 37 patients with gallbladder diseases between 2009 and 2017. All patients underwent CEUS examinations and additional cross-sectional imaging was also performed: CT imaging on 24 (64.9%) patients, MRI imaging on 18 (48.6%) patients, CT and MRI imaging on (28.7%). CEUS images were performed and interpreted by a single physician. RESULTS: CEUS imaging results of the gallbladder showed a sensitivity and specificity of 100%, a positive predictive value (PPV) of 100% and a negative predictive value (NPV) of 100%. CT imaging of the gallbladder showed a sensitivity of 100%, specificity of 75%, PPV of 100%, and NPV of 95%. MR imaging of the gallbladder showed a sensitivity of 100%, specificity of 93%, PPV of 75%, and NPV of 100%. CONCLUSION: Ultrasound imaging plays an essential role in the evaluation of gallbladder disease. Due to additional features of contrast-enhanced ultrasound, it is possible to differentiate gallbladder pathologic alterations by depicting its micro and macrocirculation and display important malignant features that recommends prompt management. Patients with contraindications to other cross-sectional imaging modalities benefit from this safe technique.

Contrast-enhanced ultrasound (CEUS) and gallbladder diseases - A retrospective mono-center analysis of imaging findings with histopathological correlation.

BACKGROUND: Radiologic imaging, especially ultrasound has an important role in the assessment of gallbladder alteration. Contrast-enhanced ultrasound (CEUS) is an easy and fast imaging technique that overcomes the limitations of greyscale ultrasonography. It is a safe tool that can be used as an additional imaging modality in order to elucidate and differentiate gallbladder pathological findings. OBJECTIVE: The aim of this retrospective study analysis is to assess the diagnostic performance of CEUS in gallbladder alterations and compare the results to the histopathological findings. METHODS: A total of 17 patients between 2009 and 2017 with uncertain gallbladder appearance were retrospectively analysed. A single experienced physician with more than fifteen years' experience performed CEUS examinations by applying a second-generation blood pool agent (SonoVue®, Bracco, Milan, Italy). Archived images were interpreted by the same physician and compared to the histopathological findings. RESULTS: CEUS results, when correlated to the respectively pathologic findings, presented a sensitivity of 100%, a specificity of 100%, a positive predictive value (PPV) of 100% and a negative predictive value (NPV) of 100%. All patients were successfully examined without any adverse reaction. CONCLUSION: In conclusion, the excellent results in this study acknowledged that CEUS is a feasible alternative tool to differentiate gallbladder pathologic alterations.

Papillary renal cell carcinoma in contrast-enhanced ultrasound (CEUS) - A diagnostic performance study.

BACKGROUND: Renal cell carcinomas (RCC) represent a heterogeneous group of hypo- and hypervascularized malignancies. Using contrast-enhanced ultrasound (CEUS) specific imaging features of clear cell (ccRCC), papillary (pRCC) and chromophobe RCC (chRCC) subtypes have been demonstrated. However, some RCCs show atypical imaging features making it difficult to distinguish between the subtypes. OBJECTIVE: This study was performed to evaluate the observed enhancement features of pRCC in CEUS and to assess the sensitivity in the diagnosis of suspected renal malignancies in a 10 year retrospective analysis at our institution. METHODS: The study population consisted of 60 patients with histologically confirmed pRCC. All patients underwent CEUS imaging between 2005 and 2015 as part of their diagnostic workup. RESULTS: In 45 out of 60 (75%) cases the examined pRCC showed typical hypoenhancement and wash-out. 15 out of 60 (25%) pRCC showed atypical enhancement features; in 14 cases the contrast enhancement indicated a ccRCC. 1 complex cyst was falsely reported as IIF lesion. 59 out of 60 malignancies were reported as malignant using CEUS resulting in a sensitivity of 98.4%. CONCLUSIONS: CEUS is an eligible imaging technique to visualize the contrast enhancement features of pRCC. However, up to 25% of pRCCs show an atypical enhancement pattern making it difficult to distinguish it from other renal lesions.

The use of contrast-enhanced ultrasound (CEUS) for the diagnostic evaluation of hepatic echinococcosis.

BACKGROUND: Hepatic echinococcosis (HE) is a zoonosis and depicts a rare but potentially lethal disease caused by larval infestation of E. multilocularis (alveolar echinococcosis, AE) and E. granulosus (cystic echinocococcosis, CE). In many countries, HE is a critical public health problem. Clinically, HE patients initially are often asymptomatic for years. Depending on the echinococcal manifestations patients can later develop unspecific symptoms as fatigue, abdominal pain and may present with elevated transaminases, jaundice and hepatomegaly. The combination of grey scale ultrasound and serological tests has been the gold standard for the screening and diagnosis of HE. Besides MRI, CT and FDG-PET scans, safe and directly accessible contrast-enhanced ultrasound (CEUS) may easily help to indirectly describe perilesional inflammation. Upon diagnosis of HE, an appropriate therapeutical strategy should be evaluated in a multidisciplinary way. OBJECTIVE: The aim of the present retrospective monocenter study is to assess the diagnostic performance of CEUS examination in the evaluation of hepatic echinococcal manifestation by comparison with CT, MRI, FDG-PET scans and histopathology. METHODS: Out of 36 patients with echinococcal disease (16 patients with E. multilocularis infection, 12 patients with E. granulosus infection and 8 patient with unspecified Echinococcus infection) 8 HE patients (4 patients with E. multilocularis, 2 patients with E. granulosus and 2 patients with unspecified echinococcal liver disease) were included in this study on whom CEUS was performed between 2008-2016. The applied contrast agent was a second-generation blood pool agent (SonoVue ®, Bracco, Milan, Italy). CEUS examinations were performed and interpreted by a single experienced radiologist with more than 15 years of experience. RESULTS: All patients were examined without occurrence of any side effects. In all 4 AE patients, contrast enhancement could be detected by means of CEUS and was confirmed by MRI or PET-CT scan. In the remaining 4 patients (CE and unspecified echinococcosis), doppler ultrasonography, CEUS and corresponding CT or MRI scans could not detect any hypervascularization of the lesions of interest. The histopathological analysis did not reveal any viable parasite material. CEUS showed a sensitivity of 100% and a specificity of 100% compared to MRI, CT or FDG-PET-CT. CONCLUSIONS: CEUS depicts a safe method for the evaluation of echinococcal liver disease. In addition to serological tests and grey scale ultrasound, CEUS imaging could be integrated as an easily accessible tool helping to describe hypervascularization as a sonomorphological correlate for active perilesional inflammation of echinococcal manifestations. CEUS may further help to differentiate between CE and AE and also to evaluate treatment outcome.

[Reliable diagnosis of cystic renal lesions]. / Sichere Diagnostik zystischer Nierenläsionen.

CLINICAL/METHODICAL ISSUE: Cystic renal lesions are commonly seen during routine ultrasound examinations of the abdomen. STANDARD RADIOLOGICAL METHODS: Some cystic renal lesions cannot be sufficiently characterized using native ultrasound. In these cases additional imaging might be necessary. METHODICAL INNOVATIONS: Contrast-enhanced ultrasound (CEUS) is a reliable imaging modality to characterize cystic renal lesions. Contrast enhancement of septations and the cystic wall are visualized in high resolution. This information helps to categorize the cystic renal lesions applying the CEUS Bosniak classification. This classification helps to estimate the probability of a malignant etiology of cystic renal lesions. PERFORMANCE: Using CEUS, cystic renal lesions can be characterized with a high sensitivity and specificity. ACHIEVEMENTS: The advantages of CEUS include that there is no effect on the function of the kidneys or the thyroid gland and no radiation exposure. In some cases, additional cross-sectional imaging is necessary to optimize diagnostic accuracy. PRACTICAL RECOMMENDATIONS: CEUS is a helpful imaging modality to characterize cystic renal lesions, to avoid unnecessary follow-ups and to detect malignant cystic renal lesions.

[CEUS-diagnostic workup of cystic renal lesions]. / CEUS ­ Diagnostik zystischer Nierenläsionen.

CLINICAL/METHODICAL ISSUE: Cystic renal lesions are common incidental findings in radiological imaging and they should be adequately examined to be able to characterize them as benign or malignant. STANDARD RADIOLOGICAL METHODS: It is not always possible to sufficiently characterize cystic renal lesion solely using native B­mode sonography and color-Doppler sonography. METHODICAL INNOVATIONS: Using contrast-enhanced ultrasound (CEUS), it is possible to dynamically evaluate the perfusion of cystic renal lesions and to characterize the potential malignancy of these lesions using the Bosniak classification in order to give recommendations regarding further work-up. CEUS can also be used in patients with contraindications for other radiological imaging modalities as it uses a contrast agent with almost no side effects. PERFORMANCE: Using CEUS, cystic renal lesions can be reliably characterized with a diagnostic accuracy greater than 90%. ACHIEVEMENTS: CEUS is a useful method in diagnosing and characterizing unclear cystic renal lesions and should always be considered as a viable diagnostic tool. PRACTICAL RECOMMENDATIONS: CEUS should always be performed in initially unclear cases and is a useful additional tool for the diagnosis and characterization of unclear cystic renal lesions.

[CEUS-diagnosis of benign liver lesions]. / CEUS ­ Diagnostik benigner Leberläsionen.

CLINICAL/METHODICAL ISSUE: Focal liver lesions are commonly seen during routine ultrasound examinations. STANDARD RADIOLOGICAL METHODS: With native ultrasound there are lesions that cannot be sufficiently characterized. In these cases additional imaging might be necessary. METHODICAL INNOVATIONS: With contrast-enhanced ultrasound (CEUS), focal liver lesions can be characterized with high diagnostic accuracy. After the ultrasound contrast agent has been injected into a peripheral vein, the examiner saves video loops of the arterial, portal venous and late contrast phases. Combing the findings of native and contrast-enhanced ultrasound allows not only assessment of the etiology as benign or malignant but also detailed characterization of the focal liver lesion in most cases. PERFORMANCE: Using CEUS, focal liver lesions can be characterized with a sensitivity of over 95% and a specificity of about 83%. ACHIEVEMENTS: The advantages of CEUS include that there is no radiation exposure and that the ultrasound contrast agent has no effects on the function of the liver, kidneys or the thyroid gland. The main limiting factors for CEUS are bowel gas and obesity of the patient. PRACTICAL RECOMMENDATIONS: CEUS can visualize micro- and macrovascularization of benign focal liver lesions in real time. It is a useful imaging modality in unclear cases.

[CEUS-Diagnostic of malignant liver lesions]. / CEUS ­ Diagnostik maligner Leberläsionen.

CLINICAL/METHODICAL ISSUE: Cross-sectional modalities or conventional ultrasound are not always able to sufficiently identify and characterize malignant liver lesions. STANDARD RADIOLOGICAL METHODS: The evaluation of malignant liver lesions in conventional ultrasound relies on echostructure, shape and borders, but often warrants additional contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI) studies. METHODICAL INNOVATIONS: Contrast-enhanced ultrasound (CEUS) is a relatively safe imaging technique used for the detection and characterization of malignant liver lesions. The use of a second-generation contrast agent in dynamic real-time imaging allows the visualization of vascularization in any kind of liver lesion as well as liver perfusion during the arterial, portal venous and late phase. PERFORMANCE: Due to the different enhancement patterns, it is possible to differentiate a liver lesion with high diagnostic accuracy (over 90%). ACHIEVEMENTS: CEUS is a helpful complementary technique to cross-sectional imaging for the evaluation of unclear liver lesions and may frequently obviate additional contrast-enhanced MRI or CT studies. PRACTICAL RECOMMENDATIONS: CEUS enables the detection and characterization of liver lesions in real time.