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

Diagnostic value of multi-parameter ultrasound evaluation in sepsis complicated by acute kidney injury

BACKGROUND

This study aimed to discuss the diagnostic value of multi-parameter ultrasound evaluation in sepsis complicated with acute kidney injury (AKI).

METHODS

Patients were divided into an AKI group (n = 50) and a non-injury group (n = 50) based on the presence of AKI. The clinical characteristics were collected, and renal function parameters between the two groups were compared, including 24-h urine volume, serum creatinine, urea, serum cystatin C (CysC), renal parenchymal thickness (RPT), renal artery resistance index (RI), and multi-parameter ultrasound scoring (MPUS). Additionally, logistic regression analysis was conducted to determine the influencing factors of sepsis complicated with AKI. The prediction value was evaluated using a receiver operating characteristic (ROC) curve.

RESULTS

In the AKI group, creatinine, CysC, urea, MPUS score, RPT, and RI values were significantly higher, while the 24-h urine volume was lower than those in the non-injury group (p < 0.01). Moreover, multivariate logistic analysis indicated that high CysC and RI values were independent risk factors, whereas high 24-h urine volume and low MPUS were independent protective factors for sepsis-induced AKI. The ROC curve demonstrated that RI (AUC = 0.906) was more effective than 24-h urine volume (AUC = 0.797), CysC (AUC = 0.730), and MPUS (AUC = 0.794) in identifying sepsis-induced AKI.

CONCLUSION

High RI values increase the risk of sepsis-induced AKI, whereas low MPUS may reduce it. RI showed high diagnosis values for sepsis complicated with AKI.

Contrast-enhanced US in Renal Transplant Complications: Overview and Imaging Features

Renal transplant is the first-line treatment of end-stage renal disease. The increasing number of transplants performed every year has led to a larger population of transplant patients. Complications may arise during the perioperative and postoperative periods, and imaging plays a key role in this scenario. Contrast-enhanced US (CEUS) is a safe tool that adds additional value to US. Contrast agents are usually administered intravenously, but urinary tract anatomy and complications such as stenosis or leak can be studied using intracavitary administration of contrast agents. Assessment of the graft and iliac vessels with CEUS is particularly helpful in identifying vascular and parenchymal complications, such as arterial or venous thrombosis and stenosis, acute tubular injury, or cortical necrosis, which can lead to graft loss. Furthermore, infectious and malignant graft involvement can be accurately studied with CEUS, which can help in detection of renal abscesses and in the differentiation between benign and malignant disease. CEUS is also useful in interventional procedures, helping to guide percutaneous aspiration of collections with better delimitation of the graft boundaries and to guide renal graft biopsies by avoiding avascular areas. Potential postprocedural vascular complications, such as pseudoaneurysm, arteriovenous fistula, or active bleeding, are identified with CEUS. In addition, newer quantification tools such as CEUS perfusion are promising, but further studies are needed to approve its use for clinical purposes. ©RSNA, 2024 Supplemental material is available for this article.

Infarcts and ischemia in the abdomen: an imaging perspective with an emphasis on cross-sectional imaging findings

Infarcts and ischemia of abdominal organs may present with acute abdominal pain, and early diagnosis is crucial to prevent morbidity and mortality. Unfortunately, some of these patients present in poor clinical conditions to the emergency department, and imaging specialists are crucial for optimal outcomes. Although the radiological diagnosis of abdominal infarcts is often straightforward, it is vital to use the appropriate imaging modalities and correct imaging techniques for their detection. Additionally, some non-infarct-related abdominal pathologies may mimic infarcts, cause diagnostic confusion, and result in delayed diagnosis or misdiagnosis. In this article, we aimed to outline the general imaging approach, present cross-sectional imaging findings of infarcts and ischemia in several abdominal organs, including but not limited to, liver, spleen, kidneys, adrenals, omentum, and intestinal segments with relevant vascular anatomy, discuss possible differential diagnoses and emphasize important clinical/radiological clues that may assist radiologists in the diagnostic process.

Diagnostic value of contrast-enhanced ultrasound in intravenous leiomyomatosis: a single-center experiences

Objective

Intravenous leiomyomatosis (IVL) is a rare disease, and few studies have focused on the diagnostic value of contrast-enhanced ultrasound (CEUS) in this condition. This study aimed to investigate the diagnostic value of CEUS in IVL and summarize the specific CEUS characteristics of IVL.

Materials and Method

From December 2016 to March 2021, 93 patients admitted to our hospital with inferior vena cava (IVC) occupying lesions were prospectively enrolled and underwent detailed ultrasound multi-modality examinations, including conventional and contrast-enhanced ultrasound scans. The diagnostic value of CEUS and conventional ultrasound (CU) in IVL was compared, and the specific IVL signs were summarized.

Results

Among the 93 patients with inferior vena cava mass, 67 were IVL while 26 were non-IVL. The inter-observer agreement of the two senior doctors was good, with Kappa coefficient = 0.71 (95% CI: 0.572–0.885). The area under the ROC curve of CU for IVL diagnosis was 0.652 (95% CI: 0.528–0.776), and its sensitivity, specificity, accuracy, positive predictive value, negative predictive value, missed diagnosis rate, and misdiagnosis rate were 61.1%, 69.2%, 63.4%, 83.7%, 40.9%, 38.8%, and 30.8%, respectively. The area under curve (AUC) for IVL diagnosis by CEUS was 0.807 (95% CI: 0.701–0.911), and the sensitivity, specificity, accuracy, positive predictive value, negative predictive value, missed diagnosis rate, and misdiagnosis rate were 82.0%, 84.6%, 82.8%, 93.2%, 64.7%, 15.4%, and 17.9%, respectively. In CEUS mode, “sieve hole sign” and “multi-track sign” were detected in 57 lesions, and the detected rate was higher than that of CU (https://loop.frontiersin.org/people/1014187 < 0.01).

Conclusion

CEUS can better show the fine blood flow inside the IVL, which is important for IVL differential diagnosis. Moreover, CEUS can obtain more information about IVL diagnosis than CU, compensating for the shortcomings of CU in detecting more blood flow within the lesion. Thus, this technique has great significance for IVL diagnosis.

Efficacy Evaluation of Ultrasound with Active Contour Model for Hemodialysis in Children with Renal Failure

This study was aimed to explore the efficacy of ultrasound with active contour model (ACM) for hemodialysis in children with renal failure. The pulse coupled neural network (PCNN) was used to extract the initial contour of the ultrasound images, and the cloud model-based ACM was used to accurately segment the images, whose effect was compared with the classic Snake model. 84 children with chronic renal failure who received hemodialysis treatment in hospital were selected as research objects. There were 42 cases in the control group who were diagnosed by conventional ultrasound and 42 cases in the observation group who were diagnosed by ultrasound with the algorithm. Then, 42 children who underwent healthy physical examination (health group) were selected for comparison of related analysis indicators. The error rates of different algorithms were compared to analyze the levels of inflammatory factors in different groups of patients after hemodialysis. The results showed that the error rate of classical Snake model was 18.87% and that of ACM algorithm model was 11.01%, and the error rate of ACM algorithm model was significantly lower ( $P<0.05$ ). After hemodialysis, the level of tumor necrosis factor (TNF)-α was 38.76 pg/mL in the observation group and 40.05 pg/mL in the control group, which was notably decreased in both groups, especially in the observation group ( $P<0.05$ ). After hemodialysis, transforming growth factor (TGF)-β1 was 7.76 ng/mL in the observation group and 7.60 ng/mL in the control group, which was significantly reduced in both groups. After treatment, UA and Scr in both groups were significantly reduced, and the reduction was more significant in the observation group ( $P<0.05$ ). HGB and RBC were significantly increased in both groups, and the increase was more significant in the observation group ( $P<0.05$ ). In summary, ACM algorithm had a good segmentation effect on the ultrasonic images of children with renal failure. This study provided guidance for clinicians to choose the algorithm for the application of ultrasonic imaging diagnosis.

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 Functional MRI of the Kidney: Current State and Future Trends with Deep Learning Approaches

BACKGROUND

 Until today, assessment of renal function has remained a challenge for modern medicine. In many cases, kidney diseases accompanied by a decrease in renal function remain undetected and unsolved, since neither laboratory tests nor imaging diagnostics provide adequate information on kidney status. In recent years, developments in the field of functional magnetic resonance imaging with application to abdominal organs have opened new possibilities combining anatomic imaging with multiparametric functional information. The multiparametric approach enables the measurement of perfusion, diffusion, oxygenation, and tissue characterization in one examination, thus providing more comprehensive insight into pathophysiological processes of diseases as well as effects of therapeutic interventions. However, application of multiparametric fMRI in the kidneys is still restricted mainly to research areas and transfer to the clinical routine is still outstanding. One of the major challenges is the lack of a standardized protocol for acquisition and postprocessing including efficient strategies for data analysis. This article provides an overview of the most common fMRI techniques with application to the kidney together with new approaches regarding data analysis with deep learning.

METHODS

 This article implies a selective literature review using the literature database PubMed in May 2021 supplemented by our own experiences in this field.

RESULTS AND CONCLUSION

 Functional multiparametric MRI is a promising technique for assessing renal function in a more comprehensive approach by combining multiple parameters such as perfusion, diffusion, and BOLD imaging. New approaches with the application of deep learning techniques could substantially contribute to overcoming the challenge of handling the quantity of data and developing more efficient data postprocessing and analysis protocols. Thus, it can be hoped that multiparametric fMRI protocols can be sufficiently optimized to be used for routine renal examination and to assist clinicians in the diagnostics, monitoring, and treatment of kidney diseases in the future.

KEY POINTS

  · Multiparametric fMRI is a technique performed without the use of radiation, contrast media, and invasive methods.. · Multiparametric fMRI provides more comprehensive insight into pathophysiological processes of kidney diseases by combining functional and structural parameters.. · For broader acceptance of fMRI biomarkers, there is a need for standardization of acquisition, postprocessing, and analysis protocols as well as more prospective studies.. · Deep learning techniques could significantly contribute to an optimization of data acquisition and the postprocessing and interpretation of larger quantities of data..

CITATION FORMAT

· Zhang C, Schwartz M, Küstner T et al. Multiparametric Functional MRI of the Kidney: Current State and Future Trends with Deep Learning Approaches. Fortschr Röntgenstr 2022; DOI: 10.1055/a-1775-8633.

Role of Contrast-Enhanced Ultrasound (CEUS) in Native Kidney Pathology: Limits and Fields of Action

Gray scale ultrasound has an important diagnostic role in native kidney disease. Low cost, absence of ionizing radiation and nephrotoxicity, short performance time, and repeatability even at the bedside, are the major advantages of this technique. The introduction of contrast enhancement ultrasound (CEUS) in daily clinical practice has significantly reduced the use of contrast enhancement computed tomography (CECT) and contrast enhancement magnetic resonance (CEMR), especially in patients with renal disease. Although there are many situations in which CECT and CEMRI are primarily indicated, their use may be limited by the administration of the contrast medium, which may involve a risk of renal function impairment, especially in the elderly, and in patients with acute kidney injury (AKI) and moderate to severe chronic kidney disease (CKD). In these cases, CEUS can be a valid diagnostic choice. To date, numerous publications have highlighted the role of CEUS in the study of parenchymal micro-vascularization and renal pathology by full integration with second level imaging methods (CECT and CEMRI) both in patients with normal renal function and with diseased kidneys. The aim of this review is to offer an updated overview of the limitations and potential applications of CEUS in native kidney disease.