Noninvasive evaluation of renal oxygenation in primary nephrotic syndrome with blood oxygen level dependent magnetic resonance imaging: Initial experience

Zhang, Rui; Wang, Yao; Chen, Feng; Wang, Qidong; Wang, Zhaoming; Chen, Yilun; Xiao, Wenbo

doi:10.1177/0300060515579117

Cited by 4 publications

(3 citation statements)

References 23 publications

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“…Some studies recommended the medulla-to-cortex ratio in R 2 * to be a more sensitive marker especially in diabetes, taking advantage of the disparate changes with disease severity in cortex vs. medulla [14]. Increased R 2 * in the cortex has been observed in chronic kidney disease (CKD) [19], with either minimal change or actually a reduction in medullary R 2 * [15,40,41]. The consensus among all respondents (Table 5; 82%) was that a novice BOLD researcher can obtain R 2 * measurements in both cortex and medulla using regions of interest (ROIs) drawn in collaboration with a radiologist.…”

Section: Discussionmentioning

confidence: 99%

Consensus-based technical recommendations for clinical translation of renal BOLD MRI

Bane

Mendichovszky

Milani

et al. 2019

Magn Reson Mater Phy

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Harmonization of acquisition and analysis protocols is an important step in the validation of BOLD MRI as a renal biomarker. This harmonization initiative provides technical recommendations based on a consensus report with the aim to move towards standardized protocols that facilitate clinical translation and comparison of data across sites. We used a recently published systematic review paper, which included a detailed summary of renal BOLD MRI technical parameters and areas of investigation in its supplementary material, as the starting point in developing the survey questionnaires for seeking consensus. Survey data were collected via the Delphi consensus process from 24 researchers on renal BOLD MRI exam preparation, data acquisition, data analysis, and interpretation. Consensus was defined as ≥ 75% unanimity in response. Among 31 survey questions, 14 achieved consensus resolution, 12 showed clear respondent preference (65-74% agreement), and 5 showed equal (50/50%) split in opinion among respondents. Recommendations for subject preparation, data acquisition, processing and reporting are given based on the survey results and review of the literature. These technical recommendations are aimed towards increased inter-site harmonization, a first step towards standardization of renal BOLD MRI protocols across sites. We expect this to be an iterative process updated dynamically based on progress in the field.

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Section: Discussionmentioning

confidence: 99%

Consensus-based technical recommendations for clinical translation of renal BOLD MRI

Bane

Mendichovszky

Milani

et al. 2019

Magn Reson Mater Phy

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“…However, assessment of renal oxygenation in vivo is still a challenge. Blood oxygen level-dependent (BOLD)-MRI is a novel, powerful, and a noninvasive technique, which can assess renal oxygenation [6,7]. The validity of BOLD-MRI in assessing renal tissue oxygenation is supported by direct measurements of tissue O 2 content by oxygen-sensitive microelectrodes [8].…”

Section: Introductionmentioning

confidence: 99%

Renal Hypoxia: An Important Prognostic Marker in Patients with Chronic Kidney Disease

et al. 2018

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Background: Blood oxygen level-dependent (BOLD)-MRI is a novel and noninvasive tool that can assess renal oxygenation. The R2* value is a parameter of tissue deoxyhemoglobin concentration detected by BOLD-MRI. The purpose of the current study was to determine the relationships between renal R2* values and clinical parameters and to determine whether renal R2* values were associated with the risk for progression of chronic kidney disease (CKD). Methods: Sixty patients with CKD were enrolled in this prospective observational study in China from March 2013 to August 2014. A region of interest-based BOLD-MRI was performed to obtain cortical and medullary R2* (CR2* and MR2*) values. Data on demographics and clinical characteristics were collected. The primary end point (CKD progression) was defined as an absolute 30% decline in the estimated glomerular filtration rates (eGFR; CKD-Epidemiology Collaboration equations) or initiation of dialysis during follow-up. Results: The CR2* and MR2* values in patients with CKD were significantly higher compared with those of healthy controls. The CR2* levels were positively associated with 24-h urinary protein excretion, blood urea nitrogen, creatinine, and uric acid but negatively associated with baseline eGFR, 24-h creatinine clearance, eGFR slope, serum albumin, and the use of angiotensin II type 1 receptor blockade. The CR2* levels had the highest areas under the curve during follow-up compared with the MR2* levels and medullary cortical ratios. The Kaplan-Meier survival analysis showed that patients with CKD in the lowest tertile of the CR2* levels had the best prognosis compared with the other 2 tertiles. Moreover, baseline eGFR and CR2* tertiles were associated with the progression of CKD in Cox proportional hazard regression models. Only CR2* tertiles correlated negatively with the eGFR slope. Conclusion: We have demonstrated that the clinical feasibility of BOLD-MRI to evaluate renal oxygenation and cortex hypoxia aggravates with the decline of renal function, and cortex hypoxia was a prognostic marker in the progression of CKD.

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“…Over the last two decades, BOLD MRI has been widely used to assess changes in renal oxygen level in various kidney disease conditions, for instance, ischemic [18], hypertensive [19], diabetic [20-23] and contrast [24-26] nephropathies as well as nephrotic syndrome [27], lupus nephritis [28, 29], chronic kidney disease [30-32], acute kidney injury [33, 34] and renal allograft rejection [35-39]. It is interesting to note that BOLD MRI studies with many analytical methods in patients with different etiologies have shown inconsistent and contradictory results, reporting higher or lower R2* values.…”

Section: Introductionmentioning

confidence: 99%

Methods of Blood Oxygen Level-Dependent Magnetic Resonance Imaging Analysis for Evaluating Renal Oxygenation

Chen

Sun

2018

Kidney Blood Press Res

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Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI) has recently been utilized as a noninvasive tool for evaluating renal oxygenation. Several methods have been proposed for analyzing BOLD images. Regional ROI selection is the earliest and most widely used method for BOLD analysis. In the last 20 years, many investigators have used this method to evaluate cortical and medullary oxygenation in patients with ischemic nephropathy, hypertensive nephropathy, diabetic nephropathy, chronic kidney disease (CKD), acute kidney injury and renal allograft rejection. However, clinical trials of BOLD MRI using regional ROI selection revealed that it was difficult to distinguish the renal cortico-medullary zones with this method, and that it was susceptible to observer variability. To overcome these deficiencies, several new methods were proposed for analyzing BOLD images, including the compartmental approach, fractional hypoxia method, concentric objects (CO) method and twelve-layer concentric objects (TLCO) method. The compartmental approach provides an algorithm to judge whether the pixel belongs to the cortex or medulla. Fractional kidney hypoxia, measured by using BOLD MRI, was negatively correlated with renal blood flow, tissue perfusion and glomerular filtration rate (GFR) in patients with atherosclerotic renal artery stenosis. The CO method divides the renal parenchyma into six or twelve layers of thickness in each coronal slice of BOLD images and provides a R2* radial profile curve. The slope of the R2* curve associated positively with eGFR in CKD patients. Indeed, each method invariably has advantages and disadvantages, and there is generally no consensus method so far. Undoubtedly, analytic approaches for BOLD MRI with better reproducibility would assist clinicians in monitoring the degree of kidney hypoxia and thus facilitating timely reversal of tissue hypoxia.

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Noninvasive evaluation of renal oxygenation in primary nephrotic syndrome with blood oxygen level dependent magnetic resonance imaging: Initial experience

Cited by 4 publications

References 23 publications

Consensus-based technical recommendations for clinical translation of renal BOLD MRI

Consensus-based technical recommendations for clinical translation of renal BOLD MRI

Renal Hypoxia: An Important Prognostic Marker in Patients with Chronic Kidney Disease

Methods of Blood Oxygen Level-Dependent Magnetic Resonance Imaging Analysis for Evaluating Renal Oxygenation

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