[Explaining radiation dose exposure : The role of the banana equivalent dose compared to the effective dose in patient communication]. / Strahlenexposition erklären : Die Rolle der Bananenäquivalentdosis im Vergleich zur effektiven Dosis im Rahmen der Patientenkommunikation.

BACKGROUND AND OBJECTIVES: Communicating the amount and effects of ionizing radiation to patients prior to an examination using x­rays is associated with challenges: first, calculating the expected dose prior to the examination and, second, quantifying and illustrating cancer risks. Analogies, such as comparing radiation exposure to accident risks, have limitations and may evoke unease. This study explores and compares two new approaches to discuss radiation exposure from common clinical examinations with patients: effective dose and exposure based on radioactive potassium-40 intake from the ingestion of bananas, the banana equivalent dose (BED). MATERIALS AND METHODS: The effective doses of the diagnostic reference levels (DRL) for computed tomography (CT) and X-ray examinations in adults were calculated using mean conversion factors for specific anatomic body regions. For the BED calculation of the diagnostic reference levels, the radiation dose from a conventional banana ingested over 50 years per becquerel was calculated. The outcomes were juxtaposed against an equivalent number of bananas and its respective radiation doses. RESULTS: The calculated doses, namely effective dose and BED, of the German DRL can serve as a reliable metric to discuss radiation exposure from medical imaging with patients prior to an examination. CONCLUSION: This is the first study to calculate the effective doses of the current DRL and to compare these with the pseudoscientific unit BED. While the BED serves as an interesting illustration to metaphorize radiation exposure, it is recommended to use the calculated effective dose of the DRL as the basis for educational consultations with 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.

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.

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.

[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.

Evaluation of renal lesions using contrast-enhanced ultrasound (CEUS); a 10-year retrospective European single-centre analysis.

OBJECTIVE: To investigate the usefulness of contrast-enhanced ultrasound (CEUS) in the evaluation of renal masses. METHODS: This study included 255 patients with renal masses. Ages ranged from 18-86 years. CEUS was used for determining malignancy or benignancy and findings were correlated with the histopathological outcome. Out of 255 lesions, 212 lesions were malignant (83.1%) and 43 were benign (16.9%). Diagnostic accuracy was tested using the histopathological diagnosis as the gold standard. RESULTS: CEUS showed a sensitivity of 99.1% [95% confidence interval (CI): 96.7%, 99.9%], a specificity of 80.5% (CI: 65.1%, 91.2%), a positive predictive value of 96.4% (CI: 93.0%, 98.4%) and a negative predictive value of 94.3% (CI: 80.8%, 99.3%). Kappa for diagnostic accuracy was κ = 0.85 (CI: 0.75, 0.94). Of 212 malignant lesions, 200 renal cell carcinomas and 12 other malignant lesions were diagnosed. Out of 43 benign lesions, 10 angiomyolipomas, 3 oncocytomas, 8 renal cysts and 22 other benign lesions were diagnosed. CONCLUSION: CEUS is an useful method to differentiate between malignant and benignant renal lesions. To date, to our knowledge, this is the largest study in Europe for the evaluation of renal lesions using CEUS with a histopathological validation. KEY POINTS: • CEUS helps clinicians detect and characterise unclear solid and cystic renal lesions • CEUS shows a high diagnostic accuracy in the characterization of these lesions • Proper surgical treatment or follow-up can be given with better diagnostic confidence.

Contrast-enhanced ultrasound (CEUS) as a new technique to characterize suspected renal transplant malignancies in renal transplant patients in comparison to standard imaging modalities.

BACKGROUND: Renal transplant patients have a higher risk for malignancies of the renal transplant. In most cases suspected renal malignancies will be detected during the regular ultrasound follow-up and will require cross-sectional imaging to rule out a malignant aetiology. But it is well known that contrast agents for computed tomography or magnetic resonance imaging are critical in patients with limited renal function. OBJECTIVE: This study aims to compare the sensitivity and specificity of contrast-enhanced ultrasound (CEUS) and gold standard imaging modalities in characterizing suspected renal transplant malignancies in renal transplant patients. METHODS: A total of 22 renal transplant patients who underwent one or more CEUS examinations and at least one standard imaging modality (CT or MRI) between 2005 and 2017 were included. Patient ages ranged from 28.2 years to 74.6 (mean age 55.7 years; SD±13.0 years). CEUS of 22 patients was correlated with a standard imaging modality, CT (15 out of 22) or MRI (7 out of 22), serving as gold standard. RESULTS: CEUS showed a sensitivity of 100%, a specificity of 94.4%, a positive predictive value (PPV) of 80%, and a negative predictive value (NPV) of 100%. CONCLUSIONS: CEUS is an eligible method to help characterizing suspected renal malignancies in renal transplant patients compared to the well-established imaging modalities CT and MRI. As an imaging modality with no nephrotoxic effects CEUS can be used repeatedly even in patients with limited renal function.

Vascular rejection in renal transplant: Diagnostic value of contrast-enhanced ultrasound (CEUS) compared to biopsy.

BACKGROUND: Despite of the more potent immunosuppressive medication, vascular rejection is still a major issue after renal transplantation. Renal biopsy is the gold standard diagnostic to evaluate acute and chronic allograft rejection. As it is an invasive diagnostic there is the risk of complications like haematoma, arteriovenous fistulas, active bleeding or infection. Contrast-enhanced ultrasound is a non-invasive imaging modality that allows visualising renal transplant perfusion. OBJECTIVE: To analyse the sensitivity and specificity of contrast-enhanced ultrasound (CEUS) compared to biopsy as gold standard in diagnosing vascular rejection in renal transplant patients. METHODS: A total of 57 renal transplant recipients with poor renal allograft function with initial diagnostic imaging between 2006 and 2017 were included in the study. Clinical data and imaging studies were analysed retrospectively. The diagnostic accuracy of CEUS in diagnosing vascular rejection of the renal transplant was compared to renal biopsy as gold standard. Out of 57 patients 7 patients showed signs of vascular rejection in biopsy. In 6 out of these 7 patients CEUS described irregularities in renal perfusion suspicious of vascular rejection. RESULTS: CEUS showed a sensitivity of 85.7%, a specificity of 100%, a positive predictive value (PPV) of 100%, and a negative predictive value (NPV) of 98.0%. CONCLUSIONS: CEUS is a safe, non-nephrotoxic imaging modality for the initial imaging of renal transplant recipients with elevated kidney function parameters suspicious of vascular rejection. Compared to renal biopsy as gold standard CEUS shows a high specificity and PPV in detecting signs of vascular rejection. Since sub-types of vascular rejection with cellular and humoral components with greater risk for allograft loss have been described renal biopsy is inevitable in these cases.

Diagnostic performance of contrast-enhanced ultrasound (CEUS) for the evaluation of gallbladder diseases1.

BACKGROUND: Contrast-enhanced ultrasound (CEUS) has been used as an additional imaging technique to conventional ultrasound in order to clarify gallbladder findings, CEUS is easy and fast to perform, overcomes the limitations of gray-scale ultrasonography and is a safe tool. OBJECTIVE: The aim of this retrospective mono-center analysis study is to evaluate the diagnostic performance of CEUS in the assessment of gallbladder disease by comparing its results with additional CT findings. METHODS: A total of 24 patients between 2009 and 2017 with unclear gallbladder appearance were retrospectively analysed. The contrast agent administered was a second-generation blood pool agent (SonoVue®, Bracco, Milan, Italy). Examinations were performed and interpreted by a single experienced radiologist with more than fifteen years' experience. RESULTS: 24 patients were successfully examined without any adverse reaction. CEUS presented a sensitivity of 75%, a specificity of 100.0%, a positive predictive value of 100.0% and a negative predictive value of 95%. CONCLUSIONS: In conclusion, the excellent results in this study acknowledged that CEUS is a feasible alternative tool to differentiate gallbladder pathologic alterations.

The diagnostic value of contrast-enhanced ultrasound (CEUS) as a new technique for imaging of vascular complications in renal transplants compared to standard imaging modalities.

BACKGROUND: Vascular complications in renal transplant patients are a well-known issue in post transplant patient care. If malfunctioning of the renal transplant is suspected to be caused by vascular complications an early diagnosis and therapy is required to maintain the renal transplant. Computed tomography (CT), digital substraction angiography (DSA) and radioisotope renography are the gold standard imaging modalities to diagnose vascular complications. OBJECTIVE: To analyse the sensitivity and specificity of contrast-enhanced ultrasound (CEUS) in comparison to the standard imaging modalities CT, DSA and radioisotope renography in the diagnosis of vascular complications in renal transplant patients. METHODS: A total of 33 renal transplant recipients with elevated kidney function parameters with initial diagnostic imaging between 2006 and 2017 were included in the study. The imaging studies and clinical data were analysed retrospectively. The diagnostic accuracy of CEUS was compared to CT, DSA and renal scintigraphy respectively which are classified as gold standard for diagnosis of vascular complications in renal transplant patients. Out of 23 patients 15 patients showed vascular complications in CT, DSA or radioisotope renography and in 15 out of 15 patients CEUS detected the vascular complication. RESULTS: CEUS showed a sensitivity of 100%, a specificity of 66.7%, a positive predictive value (PPV) of 71.4%, and a negative predictive value (NPV) of 100%. CONCLUSIONS: CEUS is a non-nephrotoxic and safe method for the initial imaging of vascular complications in renal transplant recipients. Compared to the gold standard imaging modalities CT, DSA and radioisotope renography CEUS shows a high sensitivity and NPV in detecting vascular complications. In cases with suspected stenosis of the transplant renal artery additional DSA might be needed.