Die Bosniak-Klassifizierung von Nierenzysten im kontrastmittelunterstützten Ultraschall (CEUS) vergleichend zur Computertomographie und Magnetresonanztomographie

Background: Since the introduction in 1986 the Bosniak classification is the primary tool for morphologic evaluation and treatment planning of cystic renal lesions. Over the last decade the use of contrast-enhanced ultrasound (CEUS) in the diagnostic algorithm of complex renal cysts was rapidly increasing. Bosniak classification in CEUS is comparable to gold standard computed tomography (CT) but seems to upgrade cystic lesions in a small number of cases. This study investigates whether the Bosniak classification of renal cysts in CEUS examinations is comparable to gold standard CT or magnetic resonance imaging (MRI). Methods: The Bosniak classification of retrospectively evaluated CEUS examinations was compared to contrast-enhanced follow up imaging CT or MRI. For detection of malignancy the results were compared to histopathological report, if available. If case of missing CT and MRI initial CEUS examinations were compared to CEUS follow up after six months. All CEUS examinations were performed by experts in the field of ultrasound with more than 10 years of experience in the application of CEUS (EFSUMB level 3). Results: Overall 270 cystic renal lesions were included into the analysis (median age 66 years [IQR, 57-73], 63% male patients). Using Bosniak-classification 23/83 renal cysts (28%) were rated different compared to CT with a downgrade of 19 cystic lesions (23%) and an intra-class-correlation coefficient of 0.824 (p<0.001). 38/86 cystic lesions (44 %) were up- and downgraded by CEUS compared to MRI especially in classes Bosniak IIF (n=16/31) und Bosniak III (n=16/28) with an intra-class-correlation coefficient of 0.651 (p<0,001). In 97 CEUS follow-Up examinations no change was detected in Bosniak classes I and III, while a different rating was described in 12 lesions (7 Bosniak IIF downgraded to Bosniak II and 5 Bosniak II lesions upgraded in Bosniak IIF). Conclusion: CEUS-Bosniak classification showed excellent correlation to CT and only moderate correlation to MRI, especially in intermediate complex renal cysts (Bosniak IIF and III). Due to the sensitive detection of microbubbles, CEUS can even visualize finest septal and small nodular wall enhancement which may result in an upgrade of cystic lesions into a higher Bosniak class compared to CT.Seit der Einführung 1986 wurde die Bosniak-Klassifikation zur morphologischen Beurteilung und Therapieplanung von zystischen Nierenläsionen verwendet. In den letzten Jahren gewann der Kontrastmittelultraschall (CEUS) im diagnostischen Algorithmus komplexer Nierenzysten zunehmend an Bedeutung. Insgesamt vergleichbar zum Goldstandard, der Computertomographie (CT), scheint CEUS jedoch Nierenzysten teilweise höher einzustufen. In dieser Studie soll die Vergleichbarkeit der Bosniak-Klassifikation von CEUS zu den schnittbildgebenden Verfahren CT und MRT untersucht werden. Methoden: In einem multizentrischen, retrospektiven Design wurde die Bosniak-Klassifikationen der CEUS–Untersuchungen von zystischen Nierenläsionen mit im kurzfristigen Zeitintervall durchgeführten Verlaufskontrollen (kontrastmittelgestützter CT oder MRT) und, sofern vorhanden, mit den histopathologischen Befunden verglichen. Native Verlaufskontrollen wurden ausgeschlossen. Bei fehlender Schnittbildgebung wurde das CEUS Follow-UP nach 6 Monaten als Vergleich herangezogen. Alle CEUS-Untersuchungen wurden von erfahrenen Radiologen auf dem Gebiet der Kontrastmittelsonographie durchgeführt (mehr als 10 Jahre Erfahrung in CEUS). Ergebnisse: Insgesamt konnten 270 zystische Nierenläsionen eingeschlossen werden (medianes Alter 66 Jahre [IQA: 57-73], 63% männlich). Aus 83 mit der CT verglichenen Untersuchungen wurden 23 Nierenzysten (28%) unterschiedlich bewertet, in 19 Fällen (23%) folgte eine Einstufung in eine niedrigere Bosniak-Klasse. Insgesamt erreichen CEUS und die CT eine exzellente Vergleichbarkeit (ICC: 0,824, p<0.001). Aus 86 Vergleichsuntersuchungen mit der MRT wurden insgesamt 38 zystische Nierenläsionen unterschiedlich bewertet (44%), sowohl in höhere als auch niedrigere Bosniak-Klassen (ICC: 0,651, p<0,001). Unterschiede fanden sich insbesondere in den Gruppen Bosniak IIF (n=16/31) und Bosniak III (n=16/28). In 97 CEUS Follow-Up Untersuchungen gab es keine Änderung in den Gruppen I und III, 12 Läsionen aus den Gruppen Bosniak II und IIF wurden unterschiedlich bewertet (7 Läsionen aus der Bosniak-Klasse IIF zu Bosniak II, 5 Läsionen aus der Bosniak-Klasse II zu Bosniak IIF). Schlussfolgerung: Die Bosniak-Klassifikation von CEUS zeigt eine bessere Vergleichbarkeit mit der CT (Goldstandard) als mit der MRT. Die häufigsten Unterscheidungen kommen in den Klassen der komplexen Nierenzysten Bosniak IIF und vor. Durch die hochsensitive und dynamischen Kontrastmitteldarstellung von CEUS in der Evaluation zystischer Nierenläsionen kann diese zu einem Upgrade in der Bosniak-Klassifikation führen, weshalb eine s Anpassung der Bosniak-Klassifikation in Erwägung gezogen werden sollte

Quality Assessment of CEUS in Individuals with Small Renal Masses—Which Individual Factors Are Associated with High Image Quality?

Obesity and bowel gas are known to impair image quality in abdominal ultrasound (US). The present study aims at identifying individual factors in B-mode US that influence contrast-enhanced US (CEUS) image quality to optimize further imaging workup of incidentally detected focal renal masses. We retrospectively analyzed renal CEUS of focal renal masses <= 4 cm performed at our center in 143 patients between 2016 and 2020. Patient and lesion characteristics were tested for their influence on focal and overall image quality assessed by two experienced radiologists using Likert scales. Effects of significant variables were quantified by receiver operating characteristics (ROC) curve analysis with area under the curve (AUC), and combined effects were assessed by binary logistic regression. Shrunken kidney, kidney depth, lesion depth, lesion size, and exophytic lesion growth were found to influence focal renal lesion image quality, and all factors except lesion size also influenced overall image quality. Combination of all parameters except kidney depth best predicted good CEUS image quality showing an AUC of 0.91 (p < 0.001, 95%-CI 0.863-0.958). The B-mode US parameters investigated can identify patients expected to have good CEUS image quality and thus help select the most suitable contrast-enhanced imaging strategy for workup of renal lesions

Assessment of Renal Transplant Perfusion by Contrast-Enhanced Ultrasound after Switch from Calcineurin Inhibitor to Belatacept: A Pilot Study

Calcineurin inhibitors (CNIs) have improved short-term kidney allograft survival but are nephrotoxic and vasoconstrictive. Vasoconstriction is potentially reversible after switching from CNIs to belatacept. The kidney allograft shows optimal requirements for dynamic perfusion imaging using contrast-enhanced ultrasound (CEUS). We performed standardized CEUS in patients after switching from CNIs to belatacept for clinical indication to study the suitability of CEUS, in order to assess the effects of CNI cessation on kidney allograft perfusion. Eleven kidney transplant patients were enrolled from February 2020 until November 2020. Demographic, clinical, and laboratory parameters, as well as perfusion imaging, were assessed at baseline and 6 months after switching immunosuppression. Quantification of perfusion imaging on CEUS was performed using a post-processing software tool on uncompressed DICOM cine loops. After CNI cessation, estimated glomerular filtration rate increased by 4.8 mL/min/1.73 m(2) (16%). Despite good quality of fit and comparable regions of interest in baseline and follow-up CEUS examinations, quantification of perfusion imaging showed a slightly improved cortical perfusion without reaching statistical significance after CNI cessation. This is the first study that systematically investigates the suitability of CEUS to detect changes of microvascular perfusion in kidney transplant recipients in vivo. No significant differences could be detected in perfusion measurements before and after CNI cessation

Assessment of Parotid Gland Tumors by Means of Quantitative Multiparametric Ultrasound (mpUS)

Objective: The preoperative diagnostical differentiation of parotid gland tumor (PGT) is not always simple due to several different entities. B-mode-ultrasound (US) remains the imaging modality of choice, while histopathology serves as the gold standard for finalizing the diagnosis. We aimed to evaluate the use of multiparametric US (mpUS) in the assessment of PGT. Methods: We included 97 PGTs from 96 patients. A standardized mpUS protocol using B-mode-US, shear-wave elastography (SWE), and standardized contrast-enhanced ultrasound (CEUS) was performed prior to surgical intervention. SWE was assessed by real-time measurement conducting a minimum of five measurements, while quantitative CEUS parameters were assessed with a post-processing perfusion software. Results: SWE allowed differentiation between benign PGT (Warthin's Tumor (WT) paired with lymph nodes (LN) and pleomorphic adenoma (PA)), and WT and LN were softer compared to PA. WT showed lower velocities than squamous cell carcinoma (SCC): the most common malignant PGT. CEUS parameters showed significant group differences between WT and PA, WT and malignant lesions, WT and SCC, WT paired with LN versus PA, and WT paired with LN versus SCC. Conclusion: MpUS seems to be beneficial in the assessment of PGT characterization, with benign PGT appearing to be softer in SWE than tumors with malignant tendencies. The quantitative CEUS parameter shows higher perfusion in WT than in PA, and malignant PGTs are less vascularized than WTs

Cost‐effectiveness analysis of multiple imaging modalities in diagnosis and follow‐up of intermediate complex cystic renal lesions

Objectives: To compare health-economic aspects of multiple imaging modalities used to monitor renal cysts, the present study evaluates costs and outcomes of patients with Bosniak IIF and III renal cysts detected and followed-up by either contrast-enhanced computed tomography (ceCT), contrast-enhanced magnetic resonance imaging (ceMRI), or contrast-enhanced ultrasonography (CEUS). Patients and methods: A simulation using Markov models was implemented and performed with 10 cycles of 1 year each. Proportionate cohorts were allocated to Markov models by a decision tree processing specific incidences of malignancy and levels of diagnostic performance. Costs of imaging and surgical treatment were investigated using internal data of a European university hospital. Multivariate probabilistic sensitivity analysis was performed to confirm results considering input value uncertainties. Patient outcomes were measured in quality-adjusted life years (QALY), and costs as averages per patient including costs of imaging and surgical treatment. Results: Compared to the 'gold standard' of ceCT, ceMRI was more effective but also more expensive, with a resulting incremental cost-effectiveness ratio (ICER) >€70 000 (Euro) per QALY gained. CEUS was dominant compared to ceCT in both Bosniak IIF and III renal cysts in terms of QALYs and costs. Probabilistic sensitivity analysis confirmed these results in the majority of iterations. Conclusion: Both ceMRI and CEUS can be used as alternatives to ceCT in the diagnosis and follow-up of intermediately complex cystic renal lesions without compromising effectiveness, while CEUS is clearly cost-effective. The economic results apply to a large university hospital and must be adapted for smaller hospitals

Solitary peliosis hepatis mimics a liver metastasis on contrast-enhanced ultrasound

Peliosis hepatis remains a rare focal liver lesion with inconclusive imaging features. The unknown pathogenesis represents a wide possible range of etiologies including the breakdown of the sinusoidal borders, a potential hepatic outflow obstruction or dilatation of the central vein of a hepatic lobule. In histopathology, a blood-filled cystlike appearance with sinusoidal dilatation was reported. On ultrasound, B-mode features are not specific demonstrating a irregular, moreover hypoechogenic focal liver lesions. Postcontrast imaging features on Contrast-Enhanced-Ultrasound may mimic a malignant lesion with irregular contrast inflow and washout during late phase. Our case demonstrates a peliosis hepatis with malignant image features on contrast-enhanced ultrasound, ruled out by PET-CT and core needle biopsy with corresponding histopathological workup

Acute Effects of Running on Shear Wave Elastography Measures of the Achilles Tendon and Calf Muscles in Professional Female Handball and Volleyball Players

Shear Wave Elastography (SWE) is currently used to detect tissue pathologies, i.e., tendinopathy. For preventive medicine, it is important to examine the sensitivity of SWE and to investigate how stiffness measures are affected by methodological variables. The aim of this study is to examine shear wave elastography (SWE) measures in order to compare the pre- and post-running values and to determine the correlation between the shear wave speed values (m/s). SWE examinations of the Achilles tendon (AT), soleus muscle (MS) and gastrocnemius muscle (MG)) were performed in 24 healthy professional female athletes. Measurements of the shear wave speed (m/s) were taken before and after incremental treadmill running until exhaustion. Correlations were investigated using the Pearson correlation coefficient and were examined for significance using the Student’s t-test. The pre- and post-exercise shear wave speed did not differ. The pre-exercise and post-exercise stiffness for MS (r = 0.613), MG (r = 0.609) and AT (r = 0.583) correlated strongly. The pre-exercise values and changes in stiffness showed a significant correlation (p < 0.001). In professional athletes, acute exercise induces different tissue stiffness changes in AT, MS and MG for each individual. Thus, exercise activity immediately prior to the SWE measurement needs to be factored in when evaluating tissue stiffness

Vascular pattern and diagnostic accuracy of contrast-enhanced ultrasound (CEUS) in spleen alterations

BACKGROUND: Contrast-enhanced ultrasound (CEUS) has been used as an additional imaging technique in order to clarify rare focal splenic lesions (FSL). CEUS is a safe and cost-effective modality for assessment of perfusion. OBJECTIVE: To validate contrast enhancement pattern and evaluate the diagnostic accuracy of CEUS in unclear FSL. METHODS: CEUS examinations of the spleen in 50 patients between 2012 and 2018 were included in the study. Examinations were performed using B-mode, colour-coded Doppler ultrasound (CCDS) and CEUS after injection of sulphur hexafluoride microbubbles and interpreted in consensus by two experienced radiologists. Reference standard was defined as histopathological report and clinical course (treatment response, long term follow up). RESULTS: All patients were successfully examined by CEUS without an adverse reaction. CEUS presented the correct differentiation of benign and malignant alterations in 49/50 (98%). Lesion washout was found in all malignant but also 16.7% of all benign lesions. Matched to the histopathological report and clinical follow up, CEUS represented a sensitivity of 100% (95%-CI, 57-100), a specificity of 98% (95%-CI, 88-100), a positive predictive value (PPV) of 83% (95%-CI, 44-97) and a negative predictive value (NPV) of 100% (95%-CI, 92-100). CONCLUSION: CEUS may provide additional information by visualization of dynamic contrast enhancement pattern to differentiate benign and malignant lesions. Nevertheless, established criteria for malignancy (early enhancement or washout) in FSL should be considered with caution since they are also found in benign lesions

Clinical Applicability of Ultrasound Shear Wave Elastography in Patients under Hypoglossal Nerve Stimulation Therapy

Relationship between stiffness of genioglossi (GG) and geniohyoidei (GH) muscles under electric hypoglossal nerve stimulation therapy (HNS) in relation to success of therapy was investigated with additional special focus on tongue movement. Patients and Methods: Clinical and sleep laboratory parameters of a cohort of 18 patients with known shear wave velocity (SWV) data of the ipsilateral and contralateral musculi GG and GH (sGG, sGH and nGG, nGH) before and under HNS therapy were analyzed. The SWV was already determined using the ultrasonic shear wave elastography (US-SWE) technique. Results: Median Epworth Sleepiness Scale (ESS) was 8 (IQR 12), median baseline Apnoe–Hypopnoe Index (AHI) 31.65 (IQR 25.1), median AHI under HNS therapy 16.3 (IQR 20.03). Therapy success: 9/18 patients (AHI during therapy p = 0.006). Patients with bilateral protrusion of the tongue differed regarding to therapy success in increase in SWV in sGG (p = 0.032). Tongue protrusion to contralateral: A significant difference between patients with AHI during therapy p = 0.021) was seen, with also a correlation to the current AHI under therapy (p = 0.047) and the change factor of the AHI (p = 0.015). Conclusion: Stiffness of the target muscle does not appear to be an isolated measure of the success of HNS therapy. This observation may have implications for future decision-making processes in the process of titrating electrical therapy parameters. But the technique of US-SWE may be useful for future research of the neurophysiology of the tongue and OSA phenotyping