Fig 2 - available from: BMC Nephrology
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Inter-reader agreement. The rate of agreement between the two readers was calculated for each individual lesion characteristic, the Bosniak class designation (or solid designation) and the overall designation of malignant or benign based on Bosniak class (Bosniak I, II and IIF considered benign and Bosniak III, IV and solid considered malignant)
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Background:
Patients with chronic kidney disease are at increased risk of cystic kidney disease that requires imaging monitoring in many cases. However, these same patients often have contraindications to contrast-enhanced computed tomography and magnetic resonance imaging. This study evaluates the accuracy of contrast-enhanced ultrasound (CEUS),...
Context in source publication
Context 1
... agreement CEUS inter-reader agreement results are shown in Fig. 2. The highest rate of agreement was seen with calcifications (89%), overall malignant/benign designation (87%), mural nodules (83%) and lesion enhancement (80%). The lowest rate of agreement was with Bosniak class (57%), septa (63%) and rim enhancement (65%). Low rate of Bosniak class agreement was not surprising as there are 6 possible ...
Citations
... Multiple studies have confirmed the high diagnostic accuracy of CEUS in the categorization of complex cystic renal lesions [36,47,[49][50][51][52][53][54][55][56][57][58][59][60][61][62][63]. Meta-analyses performed by Richard Barr and Zhou et al. found pooled sensitivities and specificities of 95% and 84%, respectively [46,64]. ...
... To directly compare the clinical performance of CEUS in patients with differing stage of CKD, Chang et al. performed subgroup analysis of the performance of CEUS in the detection of renal malignancy patients with advanced (stage IV, V, or ESRD) versus early (stage II or III) CKD [60]. The authors found decreased overall accuracy in advanced CKD, largely due to a decreased in specificity. ...
With the rising incidence of chronic kidney disease worldwide, an increasing number of patients are expected to require renal transplantation, which remains the definitive treatment of end stage renal disease. Medical imaging, primarily ultrasonography and contrast-enhanced CT and/or MRI, plays a large role in pre-transplantation assessment, especially in the characterization of lesions within the native kidneys. However, patients with CKD/ESRD often have relative contraindications to CT- and MR-contrast agents, limiting their utilization within this patient population. Contrast-enhanced ultrasound (CEUS), which combines the high temporal and spatial resolution of ultrasonography with intravascular microbubble contrast agents, provides a promising alternative. This review aims to familiarize the reader with the literature regarding the use of CEUS in the evaluation of cystic and solid renal lesions and provide case examples of its use at our institution in the pre-transplant setting.
Graphical abstract
... The potential side effects of CEUS are considered to be low, which has led to increasing clinical use worldwide. There is no restriction because of renal function considerations and no influence of ultrasound contrast agents on thyroid metabolism, so CEUS can be used for examination of the liver even in patients with impaired renal function for whom CT or MRI contrast agents are no longer possible [25]. The most common ultrasound contrast agent currently used in Europe is based on sulphur hexafluoride microbubbles (SonoVue , BRACCO, Italy), which is usually administered intravenously as a bolus (1 to 2.4 mL) followed by 5 to 10 mL of NaCl. ...
Aims: To assess the value of using integrated parametric ultrasound software for contrast-enhanced ultrasonography (CEUS) of liver tumors.
Methods: 107 patients with liver tumors were studied. CEUS were performed to detect focal lesions. Parametric images were based on continuous CINE LOOPs, from the early-arterial phase (15 s) to the portal-venous phase (1 min) generated by perfusion software. The evaluations of the parametric images and their dignity for liver lesions were performed independently by an experienced and a less-experienced investigator. Computed tomography, magnetic resonance imaging scans or histological analysis were used as references.
Results: High parametric image quality were obtained in all patients. Among the patients, 44% lesions were benign, 56% were malignant. The experienced investigator correctly classified 46 of 47 (98%) as benign, and 60 of 60 (100%) as malignant tumors based on the parametric images. The less-experienced investigator correctly classified 39 of 47 (83%) as benign, and 49 of 60 (82%) malignant tumors, acheaving a high statistical accuracy of 98% with this type of diagnostic.
Conclusion: Parametric imaging for grading the malignant degree of tumor may be a good complement to existing ultrasound techniques and was particularly helpful for improving the assessments of the less-experienced examiner.
... Many studies have reported high sensitivity (86-100%) and moderate to high specificity (63-86%) when using qualitative CEUS features to diagnose kidney lesions [6,[17][18][19][20], and a particularly notable study by Barr et al., 2014 achieved remarkable sensitivity (100%) and specificity (96%) [21]. However, few studies have explored CEUS in patients with impaired kidney function [19,22,23]. ...
... However, the current literature reports few studies using CEUS to characterize kidney lesions in patients with kidney dysfunction. Prior studies have included a small subset of patients with kidney insufficiency [19,23], with one study comparing diagnostic performance in patients with and without CKD [22]. High accuracy (>89%) was reported for determining lesion pathology in the presence of abnormal kidney function, but differences in study design, assessment criteria, and final reported metrics make direct comparison to our outcomes challenging [19,23]. ...
... High sensitivity (86-100%) and moderately high specificity (63-86%) have been reported using CEUS [6,[17][18][19]21]. In CKD patients specifically, high sensitivity (96%) and moderate specificity (50%) were reported [22]. In comparison, here, we achieved a lower combined sensitivity for identifying malignant lesions (71%) but a specificity (75%) comparable to previous values. ...
We investigated the accuracy of CEUS for characterizing cystic and solid kidney lesions in patients with chronic kidney disease (CKD). Cystic lesions are assessed using Bosniak criteria for computed tomography (CT) and magnetic resonance imaging (MRI); however, in patients with moderate to severe kidney disease, CT and MRI contrast agents may be contraindicated. Contrast-enhanced ultrasound (CEUS) is a safe alternative for characterizing these lesions, but data on its performance among CKD patients are limited. We performed flash replenishment CEUS in 60 CKD patients (73 lesions). Final analysis included 53 patients (63 lesions). Four readers, blinded to true diagnosis, interpreted each lesion. Reader evaluations were compared to true lesion classifications. Performance metrics were calculated to assess malignant and benign diagnoses. Reader agreement was evaluated using Bowker’s symmetry test. Combined reader sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for diagnosing malignant lesions were 71%, 75%, 45%, and 90%, respectively. Sensitivity (81%) and specificity (83%) were highest in CKD IV/V patients when grouped by CKD stage. Combined reader sensitivity, specificity, PPV, and NPV for diagnosing benign lesions were 70%, 86%, 91%, and 61%, respectively. Again, in CKD IV/V patients, sensitivity (81%), specificity (95%), and PPV (98%) were highest. Inter-reader diagnostic agreement varied from 72% to 90%. In CKD patients, CEUS is a potential low-risk option for screening kidney lesions. CEUS may be particularly beneficial for CKD IV/V patients, where kidney preservation techniques are highly relevant.
... Contrast-enhanced US uses nonnephrotoxic microbubble contrast agents that can help characterize FPTs. However, unlike DMSA, contrastenhanced US is not widely available and clinical expertise is still limited [42,43]. ...
Background
The terms “renal regenerating nodule” and “nodular compensatory hypertrophy” are used in the literature to describe functioning pseudo-tumors (FPT) in the setting of an extensively scarred kidney. FPTs are usually discovered incidentally during routine renal imaging. Differentiating these FPTs from renal neoplasms is critical but can be challenging in the setting of chronic kidney disease (CKD) given the limitations related to using contrast-based imaging.
Case summaries
We report a pediatric case series of 5 CKD patients, with history of urinary tract infections, in which tumor-like lesions evolved in scarred kidneys and were incidentally discovered on routine renal imaging. These were diagnosed as FPT by utilizing dimercaptosuccinic acid (DMSA) imaging and showed stable size and appearance upon follow-up with ultrasound and MRI.
Conclusion
FPTs can be picked up on routine imaging of pediatric patients with CKD. Although larger cohort studies are needed to confirm these conclusions, our case series supports the evidence that DMSA scan showing uptake at the site of the mass can be a useful tool to suggest the diagnosis of FPTs in children with kidney scarring, and that SPECT DMSA scan adds more precision in picking up and accurately localizing FPTs compared to planar DMSA.
... Comparison of CEUS and MRI also demonstrated similar results with CEUS having higher diagnostic sensitivity and accuracy, but lower specificity than MRI in the characterization of renal cystic masses [16]. The high sensitivity of CEUS together with a relatively lower specificity was corroborated by further studies, thus proposing it primarily as a rule-out test for renal malignancies [17]. The noninferiority of CEUS compared to CT/MRI was also supported by a recent meta-analysis [18], and a comparison to subsequent histopathology [19]. ...
Background:
Contrast enhanced ultrasound (CEUS) is increasingly used in the evaluation of renal lesions, however, its availability remains limited. Thus, sensitive noncontrast ultrasound evaluation of renal lesion vascularity is an unmet need.
Methods:
In this single-center, retrospective study we assessed microvascular flow imaging (MV-flow) compared to CEUS in the evaluation of complex renal cysts and solid lesions. Out of 92 patients 28 were evaluated with both CEUS and MV-flow. Color Doppler, CEUS, and MV-flow was performed in 13 cases, whilst MV-flow, CEUS, and contrast-enhanced MV-flow (CE-MV-flow) was done in 16 cases. The CEUS diagnosis was considered gold standard.
Results:
MV-flow showed a substantial agreement with the CEUS diagnosis (weighted Kappa = 0.806), excluding equivocal lesions (Bosniak 2F). MV-flow substantially outperformed color Doppler (weighted Kappa = 0.77 vs. 0.133). The agreement of CE-MV-flow and MV-flow was comparable (weighted Kappa = 0.79 vs. 0.69).
Conclusion:
MV-flow significantly improves evaluation of renal lesion vascularity compared to conventional techniques. However, the sensitivity is limited for equivocal lesions (e.g. Bosniak 2F cysts). Thus, MV-flow should be used as an ancillary technique, not as a substitute to CEUS. Current MV-flow presets are ill-suited for postcontrast imaging, therefore specific presets optimized for this purpose are needed to establish its potential.
... 47 Contrast-enhanced US can be used to assess ischemic diseases, including infarction and necrosis, as well as the states of relative hypervascularization, such as malignant kidney lesions. 49,50 . ...
... Across all patients, contrast-enhanced US achieved high sensitivity (96%) and moderate specificity (50%) for malignancy detection, whereas the sensitivity dropped to 90% and specificity increased to 55% only in those with CKD. 50 However, this was based on a radiologist's interpretation of contrast-enhanced US images rather than any specific perfusion parameter. In contrast to these studies, Jeong et al 54 discovered no relationship between perfusion parameters and kidney function. ...
Ultrasound imaging is a key investigatory step in the evaluation of chronic kidney disease and kidney transplantation. It uses non-ionizing radiation, is non-invasive and generates real-time images, making it the ideal initial radiographic test for patients with abnormal kidney function. Ultrasound enables the assessment of both structural (form and size) as well as functional (perfusion and patency) aspects of the kidney, which are especially important as disease progresses. Ultrasound and its derivatives have been studied for their diagnostic and prognostic significance in chronic kidney disease and kidney transplantation. As ultrasound rapidly grows more widely accessible, now available even in handheld formats which allow for bedside ultrasound examinations. Given the trend towards ubiquity, the current use of kidney ultrasound demands a full understanding of its breadth as it and its variants become available. We describe the current applications and future directions of ultrasound imaging and its variants in the context of chronic kidney disease and transplantation in this review.
... A study conducted by Chang et al. showed a high sensitivity for diagnosing renal malignancy in patients with chronic kidney disease. CEUS sensitivity was comparable to the reported sensitivity of CT (83-100%) and MR (81-100%) among patients with and without CKD [41]. They found sensitivity to be high as 90% (95% CI 56%, 98%), and specificity was 55% in CKD patients. ...
... Oncocytoma is also a close mimicker of ccRCC. They are spherical tumors having a central scar on B mode US and may show central radiating vessels on Doppler interrogation [41]. Wu et al. and Mittal et al. found similar CEUS findings of oncocytomas which is a spoke wheel/centripetal pattern of hyperenhancement or a central scar with sustained enhancement in the delayed phase [50,54]. ...
... Metastasis and lymphoma generally show multiple focal lesions in both the kidneys which are < 3 cm and lack a capsule, though they can present as a solitary mass of variable size they show hypoenhancement in all the phases on CEUS [41]. ...
Contrast-enhanced ultrasound (CEUS) is an extension and an enhanced form of ultrasound that allows real-time evaluation of the various structures in diferent vascular phases. The last decade has witnessed a widespread expansion of CEUS
applications beyond the liver. It has shown fair potential in kidneys and its diagnostic efcacy is comparable to CT and
MRI. Ultrasound is the well-accepted screening modality for renal pathologies, however, it underperforms in the characterization of the renal masses. CEUS can be benefcial in such cases as it can help in the characterization of such incidental
masses in the same sitting. It has an excellent safety profle with no risk of radiation or contract-related nephropathy. It can
aid in the correct categorization of renal cysts into one of the Bosniak classes and has proven its worth especially in complex
cysts or indeterminate renal masses (especially Bosniak Category IIF and III). Few studies also describe its potential role
in solid masses and in diferentiating benign from malignant masses. Other areas of interest include infections, infarctions,
trauma, follow-up of local ablative procedures, and VUR. Through this review, the readers shall get an insight into the various applications of CEUS in kidneys, with imaging examples.
... CEUS can be used to characterize complex cystic renal masses, with accuracy comparable to CT and MRI and reports a concordance rate between the three imaging techniques of approximately 90% (Fig. 2) [26,29,47,48,49,50,51]. In addition, CEUS has been reported to be more sensitive than CT in demonstrating minimal wall and/or septal enhancement and solid, increasing components in complex cystic renal masses [26,29,51,52]. CEUS is also recommended for non-surgical follow-up of complex cystic kidney lesions [26,29,53]. ...
The widespread availability of cross-sectional imaging is responsible for the increased detection of small, usually asymptomatic renal masses. More than 50% of renal cell carcinomas (RCCs) represent incidental findings on noninvasive imaging. Multimodality imaging, including conventional US, contrast-enhanced US (CEUS), multiparametric CT and MRI (mpMRI) is essential in diagnosing and characterizing renal masses, but also provides information regarding its prognosis, therapeutic management, and follow-up. In this review, the imaging data for renal masses that urologists require for accurate treatment planning will be discussed. The roles of US, CEUS, CT and mpMRI in the detection and characterization of renal masses, RCC staging and follow-up of treated or untreated local RCCs will be presented. The role of percutaneous image-guided ablation in the management of RCC will also be reviewed
... Because UCAs are not nephrotoxic, they can depict lesion perfusion in children with compromised renal function who otherwise have limited or no imaging options. Using the Bosniak criteria, CEUS has successfully assessed the risk of malignancy in detected lesions in this population [39,40,52]. Kapur and Oscar [4] reported a case series of nine children with renal failure, ages 3-16 years, who could not be given CT or MRI contrast agents. ...
... The diagnostic performance of CEUS was compared to either pathology or follow-up imaging. CEUS showed high sensitivity (90%) and low specificity (55%) for malignant lesions in the 19/44 (43%) adults with chronic kidney disease when assessed by two readers [52]. The high sensitivity makes CEUS a reasonable screening examination for those with chronic kidney disease. ...
... The authors explored the difference in CEUS performance for those with early versus late chronic kidney disease. Although the study was limited by a small number of people with kidney disease, it revealed that when comparing early to advanced renal insufficiency, CEUS lesion characterization decreased in sensitivity from 100% to 83% and specificity from 72% to 41%, respectively [52]. One possible explanation for this observation is that the enhancement of the kidneys in people with renal disease is more heterogeneous and relatively reduced compared to that of normal kidneys, and that these changes in enhancement progressively worsen with advancing renal disease. ...
Pediatric applications of contrast-enhanced ultrasound (CEUS) are growing. Evaluation of the kidneys and adrenal glands in children using intravenous administration of US contrast agents, however, is still an off-label indication. Pediatric CEUS applications for kidneys are similar to those in adults, including ischemic disorders, pseudo- versus real tumors, indeterminate lesions, complex cystic lesions, complicated pyelonephritis, and abscesses. CEUS applications for evaluation of adrenal glands in children are limited, mainly focusing on the assessment and follow-up of adrenal trauma and the differentiation between an adrenal hemorrhage and a mass. This review addresses the current experience in pediatric CEUS of the kidneys and adrenal glands. By extrapolating the established knowledge for US contrast evaluations in the adult kidney to the pediatric context we can note opportunities for CEUS clinical use in children.
... [12][13][14] Similarly, kidney ultrasonography is helpful in evaluating kidney disease chronicity, but often the findings on sonography are normal despite severe kidney dysfunction. 15 Furthermore, it has also been suggested that the routine measures of kidney function probably do not identify early structural and functional changes in individuals with DM. 16 Changes in the kidneys include haemodynamic disturbances within the glomerulus with increased blood flow and pressure and this occurs early in the course of DM, which over time contributes significantly to the development of glomerulosclerosis and its attendant proteinuria. 17 Micropuncture studies have shown in experimental studies of DM that there is an elevation of intraglomerular pressure even in the absence of systemic hypertension. ...
Objective:
The aim of this study was to determine the haemodynamics of the intrarenal arteries from the relationship between resistivity index (RI) and kidney function, and to identify the predictors of high RI among patients with diabetic nephropathy (DN) and those with diabetes mellitus (DM) without DN.
Methods:
This was a cross-sectional survey of 133 participants, comprising 40 subjects with DM without DN, 53 with DM with DN and 40 healthy controls. Information obtained was demographics, lifestyle, medical and medication histories, while anthropometric and blood pressure measurements were taken. Albuminuria and estimated glomerular filtration rate were determined and RI was measured using a Doppler ultrasound scan.
Results:
The mean intrarenal artery RIs were higher among the patients with DM without DN (0.60 ± 0.04) and the group with DM with DN (0.61 ± 0.04) than in the controls (0.56 ± 0.04) (p = 0.02). Glycated haemoglobin (HbA1c) predicted high RI in the DM without DN group (OR 2.81; CI: 1.73-9.03) while hypertension (OR 3.60; CI: 1.06-12.22) predicted high RI in the DM with DN group.
Conclusions:
Elevated intrarenal artery RI was prevalent among patients with DM without DN and those with DM with DN, while elevated HbA1c level and hypertension predicted elevated RI in subjects with DM without DN and those with DM with DN.
