Intra- and Interobserver Study Investigating the Adapted EFSUMB Bosniak Cyst Categorization Proposed for Contrast-Enhanced Ultrasound (CEUS) in 2020.

BACKGROUND: To investigate the inter- and intraobserver variability in comparison to an expert gold standard of the new and modified renal cyst Bosniak classification proposed for contrast-enhanced ultrasound findings (CEUS) by the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) in 2020. MATERIALS AND METHODS: 84 CEUS examinations for the evaluation of renal cysts were evaluated retrospectively by six readers with different levels of ultrasound expertise using the modified Bosniak classification proposed for CEUS. All cases were anonymized, and each case was rated twice in randomized order. The consensus reading of two experts served as the gold standard, to which all other readers were compared. Statistical analysis was performed using Cohen's weighted kappa tests, where appropriate. RESULTS: Intraobserver variability showed substantial to almost perfect agreement (lowest kappa κ=0.74; highest kappa κ=0.94), with expert level observers achieving the best results. Comparison to the gold standard was almost perfect for experts (highest kappa κ=0.95) and lower for beginner and intermediate level readers still achieving mostly substantial agreement (lowest kappa κ=0.59). Confidence of rating was highest for Bosniak classes I and IV and lowest for classes IIF and III. CONCLUSION: Categorization of cystic renal lesions based on the Bosniak classification proposed by the EFSUMB in 2020 showed very good reproducibility. While even less experienced observers achieved mostly substantial agreement, training remains a major factor for better diagnostic performance.

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.

Contrast-enhanced ultrasound (CEUS) reliably rules out neoplasm in developmental renal pseudotumor.

BACKGROUND: Renal pseudotumors appear as benign cortical hypertrophies and are typically assessed by contrast-enhanced computed tomography or magnetic resonance imaging to rule out malignancy. PURPOSE: To investigate whether contrast-enhanced ultrasound (CEUS) can rule out renal neoplasm and thus potentially reduce cross-sectional imaging and further follow-up in these patients. MATERIAL AND METHODS: Thirty-two patients with presumption of developmental renal pseudotumor on CEUS between June 2011 and July 2019 were retrospectively analyzed. All patients were examined with a standardized renal US protocol including B-mode, color-coded duplex sonography (CCDS), and CEUS by an experienced radiologist (EFSUMB level 3). Images were retrospectively interpreted in consensus by two highly experienced radiologists. Histopathological reports, cross-sectional imaging findings, and clinical course (treatment response, long-term imaging follow-up) were defined as standard of reference. RESULTS: CEUS correctly identified 8/9 neoplastic lesions and missed one oncocytoma within the 32 included patients. Irregular vessel structure (88.9% vs. 13.0%, P = 0.007) and hyperenhancement (66.6% vs. 17.4%, P = 0.031) on CEUS were more common in neoplasm compared to developmental pseudotumors reaching statistical significance. Compared with the standard of reference, CEUS had 89% sensitivity (95% confidence interval [CI] 57-98), 96% specificity (95% CI 80-99), a positive predictive value of 89% (95% CI 57-98), and a negative predictive value of 96% (95% CI 79-99) for ruling out renal malignancy in developmental pseudotumors. CONCLUSION: CEUS is a safe and fast method to rule out neoplasm in the diagnostic work-up of renal pseudotumors. In conjunction with B-mode and CCDS, CEUS has the potential to reduce further (invasive) diagnostic procedures.

Assessment of quantitative microflow Vascular Index in testicular cancer.

PURPOSE: Ultrasound (US) is the primary imaging modality when a testicular tumor is suspected. Superb microvascular imaging (SMI) is a novel, highly sensitive Doppler technique that allows quantification of flow signals by determination of the Vascular Index (VI). The aim of the present study is to investigate the diagnostic significance of the SMI-derived VI in normal testicular tissue and testicular cancer. METHODS: This retrospective analysis included patients who underwent testicular US in our department from 2018 to 2022. Inclusion criteria were: i) sufficient image quality of the stored images, ii) US with standardized SMI-default setting (colour gain of 44 ± 5), iii) patient age ≥ 18 years, and iv) normal testicular findings or testicular tumor with histopathological workup. US examinations were performed as part of clinical routine using a high-end ultrasound system (Aplio i800/i900, Canon Medical Systems Corporation, Tochigi, Japan). Statistical analysis included Chi-square test and Mann-Whitney U tests and receiver operating characteristic (ROC) curve analysis. RESULTS: A total of 62 patients (31 each with normal findings and testicular tumors) were included. The VI differed statistically significantly (p < 0.001) between normal testis (median 2.5 %) and testicular tumors (median 17.4 %). Like vascular patterns (p < 0.001), the VI (p = 0.030) was shown to distinguish seminomas (median 14.8 %), non-seminomas (median 17.6 %) and lymphomas (median 34.5 %). CONCLUSIONS: In conclusion, our study has shown the VI to be a quantitative tool that can add information for differentiating testicular tumor entities. While further confirmation in larger study populations is desirable, our results suggest that the VI may be a useful quantitative parameter.

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.

Contrast-enhanced ultrasound (CEUS) in characterization of inconclusive cervical lymph nodes: a meta-analysis and systematic review.

Lymph node metastases are common in malignant neoplasms of head and neck. Since cervical lymph nodes (cLN) are localized superficially, ultrasound (US) represents the primary imaging modality. The aim of the study is to report the value of US and contrast-enhanced ultrasound (CEUS) and their diagnostic confidence in the characterization of inconclusive cLN. A systematic review was performed using the literature data base PubMed. Results were filtered (published in a peer-reviewed journal, full-text available, published within the last ten years, species human, English or German full-text) and inclusion criteria were clearly defined (cohort with lymphadenopathy or malignancy in head and neck ≥ 50 patients, histological confirmation of malignant imaging findings, performance of CEUS as outcome variable). The results were quantified in a meta-analysis using a random-effects model. Overall, five studies were included in qualitative and quantitative analysis. The combination of non-enhanced US and CEUS enlarges the diagnostic confidence in the characterization of lymph nodes of unclear dignity. The pooled values for sensitivity and specificity in the characterization of a malignant cervical lymph node using US are 76% (95%-CI 66-83%, I2 = 63%, p < 0.01) and 80% (95%-CI 45-95%, I2 = 92%, p < 0.01), compared to 92% (95%-CI 89-95%, I2 = 0%, p = 0.65) and 91% (95%-CI 87-94%, I2 = 0%, p = 0.40) for the combination of US and CEUS, respectively. Consistent results of the included studies show improved diagnostic performance by additional CEUS. Nevertheless, more prospective studies are needed to implement CEUS in the diagnostic pathway of cLN.

Diagnostic performance of MRI and US in suspicion of penile fracture.

Background: Penile fracture (PF) is defined as rupture of the tunica albuginea of the corpora cavernosa. While most authors agree that rapid surgical therapy of this rare pathology leads to the best patient outcome, the role of imaging is highly controversial in the published literature. To obtain further evidence concerning the diagnostic accuracies of magnetic resonance imaging (MRI) and ultrasound (US) in the diagnostic assessment of patients with suspected PF. Methods: We systematically reviewed MRI and US examinations performed in our institution between 2000 and 2021 and correlated imaging reports with either intraoperative finding or final clinical diagnosis. Inclusion criteria were: (I) patient age ≥18 years, (II) examination between 2000 and 2021, (III) information available on patient's history and clinical presentation, and (IV) documented final diagnosis in discharge letter. Next to diagnostic accuracy, we describe typical imaging findings such as penile hematoma, tear of the tunica albuginea including location in terms of side and shaft segment affected, and involvement of corpus spongiosum. Results: Overall, 46 of 88 included patients (54.5%) had a confirmed diagnosis of PF. A total of 69 MRI and 31 US examinations were included. Sensitivity and specificity were 91.9% (95% CI: 78.7-97.2%) and 90.6% (95% CI: 75.8-96.8%) for MRI and 71.4% (95% CI: 45.4-88.3%) and 100.0% (95% CI: 81.6-100.0%) for US, respectively. Conclusions: The results of the present study suggest that MRI is more suitable to confirm PF and identify the site of the associated tunica albuginea tear while US is a good tool for ruling out PF.

Diagnostic value of contrast-enhanced ultrasound (CEUS) in kidney allografts - 12 years of experience in a tertiary referral center.

BACKGROUND: B-Mode and Doppler ultrasound are standard diagnostic techniques for early postoperative monitoring and long-term follow-up of kidney transplants. In certain cases, contrast-enhanced ultrasound (CEUS) is used to clarify unclear Doppler findings. OBJECTIVE: To investigate the diagnostic performance of CEUS in the workup of renal allograft pathologies. METHODS: A systematic search for CEUS examinations of renal transplants conducted in our department between 2008 and 2020 was performed using the following inclusion criteria: i) patient age ≥18 years and ii) confirmation of diagnosis by biopsy and histopathology, imaging follow-up by CEUS, contrast-enhanced computed tomography (ceCT), contrast-enhanced magnetic resonance imaging (ceMRI), or angiography, or intraoperative findings. Exclusion criteria were: i) CEUS performed in the setting of a study and ii) CEUS for other indications than dedicated renal transplant examination. Statistical analysis was performed separately for subgroups with different indications (focal vs non-focal). RESULTS: Overall, 78 patients were included in the statistical analysis, which revealed high sensitivity (92.2%, 95% -confidence interval [CI] 81.5-96.9%) and high specificity (88.9%, 95% -CI 71.9-96.1%) of CEUS. CONCLUSIONS: The high diagnostic performance demonstrated here and the superficial location of kidney allografts advocate the additional use of CEUS in the follow-up of renal transplant recipients.

Multiparametric ultrasound findings in acute kidney failure due to rare renal cortical necrosis.

Renal cortical necrosis (RCN) is a rare cause of acute kidney failure and is usually diagnosed on the basis of characteristic enhancement patterns on cross-sectional imaging. Contrast-enhanced ultrasound (CEUS) offers benefits in patients with kidney failure in the clinical setting including the use of a nonnephrotoxic intravascular contrast agent and the fact that it can be performed at the bedside in critical cases. Therefore, the aim of this study is to investigate whether CEUS can reliably identify typical imaging features of RCN. We retrospectively analyzed 12 patients with RCN examined in our department and confirmation of the diagnosis by either histopathology, other contrast-enhanced cross-sectional imaging tests, and/or CEUS follow-up. Assessed parameters in conventional US were reduced echogenicity, loss of corticomedullary differentiation, length and width of kidney, hypoechoic rim, resistance index and in CEUS delayed wash-in of contrast agent (> 20 s), reverse rim sign, maximum nonenhancing rim and additional renal infarction. Furthermore, imaging features in RCN were compared with the findings in renal vein thrombosis (RVT), among them echogenicity, corticomedullar differentiation, hypoechoic rim, RI value, delayed cortical enhancement, total loss of cortical perfusion and enhancement of renal medulla. All 12 patients showed the reverse rim sign, while a hypoechogenic subcapsular rim was only visible in four patients on B-mode ultrasound. A resistance index (RI) was available in 10 cases and was always less than 1. RI was a strong differentiator in separating RVT from RCN (RI > 1 or not measurable due to hypoperfusion as differentiator, p = 0.001). CEUS showed total loss of medullary enhancement in all cases of RVT. With its higher temporal resolution, CEUS allows dynamic assessment of renal macro- and microcirculation and identification of the typical imaging findings of RCN with use of a nonnephrotoxic contrast agent.

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.

Multiparametric Ultrasound (mpUS) of a Rare Testicular Capillary Hemangioma.

Capillary hemangioma is a rare entity among testicular tumors. We demonstrate the case of an 18-year-old patient with palpatoric and sonographic conspicuous left testicle and negative serum tumor markers (α-fetoprotein, ß-human chorionic gonadotropin, and lactate dehydrogenase). Ultrasound (US) imaging represented an isoechogenic lesion with high vascularization in both power Doppler and microflow imaging with central feeding artery. Both strain elastography and shear wave elastography demonstrated a stiff lesion compared to surrounding testicular tissue. While contrast-enhanced ultrasound (CEUS) clearly depicted high vascular load, time intensity curve (TIC) analysis was able to show shorter median transit time, higher peak enhancement, and higher wash-in area under the curve compared to regular testicular tissue. Histopathological examination revealed a lobular constructed and rich vascularized proliferation without cellular atypia and feeder vessels with positive reaction to CD34, CD31, CD99, and Vimentin. Proliferative activity was quantified to 3-5% by Ki-67 index. Two days after surgery, the patient could leave the hospital in subjective wellbeing. While histology remains the gold standard to make a precise diagnosis of capillary hemangiomas due to small case numbers and variety of this benign tumor, the combination of multiparametric US and clinical information may be a promising future tool in preoperative assessment.