Renal Magnetic Resonance Research Articles

Renal fat deposition measured on dixon-based MRI is significantly associated with early kidney damage in obesity.

To investigate the renal fat deposition on Dixon-based magnetic resonance imaging (MRI) and to explore the predictive value of renal fat biomarkers of magnetic resonance (MR-RFBs) for early kidney damage in obesity. This prospective study included 56 obese volunteers and 47 non-obese healthy volunteers. All volunteers underwent renal magnetic resonance examinations. The differences in MR-RFBs [including renal proton density fat fraction (PDFF), renal sinus fat volume (RSFV), and perirenal fat thickness (PRFT)] measured on Dixon-based MRI between the obese and non-obese volunteers were analyzed using a general linear model, taking sex, age, diabetes, and hypertension as covariates. The relationship between estimated glomerular filtration rate (eGFR) and demographic, laboratory, and imaging parameters in obese volunteers was examined by correlation analysis. Obese volunteers had higher MR-RFBs than non-obese volunteers after controlling for confounders (all p < 0.001). Renal PDFF (r = -0.383; p = 0.004), RSFV (r = -0.368; p = 0.005), and PRFT (r = -0.451; p < 0.001) were significantly negatively correlated with eGFR in obesity. After adjusting for age, sex, body mass index, diabetes, hypertension, visceral adipose tissue, subcutaneous adipose tissue, renal PDFF, and RSFV, PRFT remained independently negatively associated with eGFR (β = -0.587; p = 0.003). All MR-RFBs are negatively correlated with eGFR in obesity. The MR-RFBs, especially PRFT, may have predictive value for early kidney damage in obesity.

#2955 Incidental findings in a renal magnetic resonance imaging study for evaluation of chronic kidney disease in type 2 diabetes population

Abstract Background and Aims Novel Magnetic Resonance Imaging (MRI) techniques are potential methods to non-invasively assess and quantify functional, structural and pathophysiological changes in chronic kidney disease (CKD) that may improve diagnosis, prognosis and treatment of these patients. Advances in imaging techniques are also likely to result in the detection of unexpected and asymptomatic incidental findings. We retrospectively analyzed the overall prevalence of incidental findings in the participants of our previously reported study utilizing a non-contrast multiparametric MRI protocol in patients with type 2 DM (T2DM) as compared to healthy controls. Method The subjects of this sub-study were participants of our original prospective, single-center, observational study, in which several MRI biomarkers were evaluated to differentiate diabetic versus healthy kidneys, and various stages of CKD. A complete medical history and physical examination were performed. The inclusion criteria for the T2DM cohort were: Age 18-70 years, type II DM with CKD staged 3-4 (estimated glomerular filtration rate [eGFR] 15-60 ml/min/1.73 m2, body mass index (BMI) 18-35 and provision of written informed consent. The control group comprised of healthy volunteers who were age- and sex-matched and had the following inclusion criteria: Age 18-70 years, eGFR &amp;gt;80 ml/min/1.73 m2, UACR &amp;lt;30 mmol/g, BMI 18-35 and provision of written informed consent. Exclusion criteria for the diabetic group were any apparent cause/s of CKD other than diabetes, previous kidney transplantation, pregnancy, contraindication for MRI examination, heart failure (NYHA class III or IV), allergies to iodine-based contrast agents. Factors that excluded healthy participants were pregnancy, contraindication for MRI examination, allergy to iodine-based contrast agents and any active or chronic disease/diagnosis. Measured GFR (mGFR) was assessed in all participants using iohexol clearance. An MRI scan using a wide range of non-contrast techniques was performed at baseline. Total scan time for patients did not exceed 45 min per session and no gadolinium-based contrast agents were used in any of the MRI examinations. All patients with incidental findings on MRI were further evaluated and referred to appropriate specialists for management. Results A total of 38 T2DM patients with CKD and 20 age- and gender-matched healthy volunteers who completed the study were included in the analysis. Of the T2DM patients, 2 were found to have CKD stage 2 by mGFR and 36 CKD stages 3–4. Clinically significant incidental findings (excluding 4 cases of renal cysts requiring only follow-up without further intervention) were found in 13 of the 38 (34%) T2DM patients. The most frequent findings were intraductal papillary mucinous neoplasm (IPMN) in 7 patients, followed by 3 cancers (1 case of kidney cancer, 1 bladder cancer and 1 lymphoma) and 3 cases of adrenal gland mass later diagnosed to be benign adenoma on further investigation. In contrast, of the 20 healthy volunteers, 2 (10%) were found to have significant incidental findings, which were IPMN in both. The follow-up duration varied between 2-6 years. The patient with bladder cancer had metastatic disease and died shortly after the diagnosis, the one with kidney cancer is under observation and the one with lymphoma underwent adequate treatment and is under remission. The cases of IPMN are being followed up regularly at our surgical department. Conclusion Clinically important incidental findings on renal MRI appear to be more common in T2DM patients than in healthy volunteers, which would have been missed without MRI examination. Mechanisms for reporting and strategies for dealing with incidental findings need to be taken into account in such investigational imaging studies. The detection of incidental findings also poses various practical and ethical issues. Further larger studies with long-term follow-up are needed to delineate the clinical relevance, natural course and management of such incidental findings.

#1040 Correlation of genotype to disease onset age and hypertension diagnosis in autosomal dominant polycystic kidney disease

Abstract Background and Aims Autosomal Dominant Polycystic Kidney Disease (ADPKD) is the predominant genetic disease leading to End Stage Kidney Disease (ESKD). Genetic identity could correlate to the disease profile. Correlations between genetic and phenotype characteristics in a cohort of ADPKD patients are investigated. Method Genetic analysis was conducted in 85 patients with an ADPKD phenotype, employing targeted Next Generation (tNGS) or Sanger Sequencing and Multiplex ligation-dependent probe amplification (MLPA). Medical history, clinical and laboratory data, including Renal Magnetic Resonance Imaging (MRI) for Total Kidney Volume (TKV) measurement (in 66 patients), were recorded and subsequently correlated to the respective genotypes. Results Eighty-five patients (43 females, 42 males, 33 ± 16 years old) were included in the study. The mean age at diagnosis of the disease was at 21.5 ± 13 (0.6-69) years. Fifty-eight out of 85 patients (68%) had a familial history of ADPKD. The mean age at which the affected parent reached ESKD was 53.0 ± 9 years. Hypertension was diagnosed in 60 individuals (71%) within the study cohort. The mean age at hypertension diagnosis was 31 ± 11 years. In the assessment based on height-adjusted TKV and age, the Mayo Clinic Imaging Categories revealed that 9% of patients were classified as 1A, 20% as 1B, 29% as 1C, 29% as 1D, and 13% as 1E. Mutations in PKD1 gene were detected in 70 patients (82%), with 61% exhibiting truncating mutations and 39% non-truncating mutations, while PKD2 mutations were identified in 15 patients (18%). The average age of ADPKD diagnosis differed among genetic subgroups. Patients carrying PKD1-truncating mutations were diagnosed at 17.6 ± 11 years, those with PKD1-non-truncating mutations at 24.5 ± 12 years, and those with PKD2 mutations at 27.3 ± 16 years (p = 0.01). Moreover, the mean age at which the affected parent reached ESKD was 50 ± 8 years, 55 ± 10 and 60 ± 7 years in PKD1-truncating, PKD1-non-truncating and PKD2 patients respectively (p = 0.04). Additionally, the mean age of hypertension diagnosis was 29 ± 12 years in PKD1-truncating, 30 ± 10 years in PKD1-non-truncating and 40 ± 7 years in PKD2 patients (p = 0.05). Conclusion Mutation type correlates with the age of ADPKD diagnosis, the renal survival within families and the hypertension onset. Patients with PKD1-truncating mutations manifest an earlier onset of both the disease and hypertension compared to those with PKD2 gene mutations.

#1232 Integrating genotype and phenotype data is required for renal survival prediction in autosomal dominant polycystic kidney disease

Abstract Background and Aims Autosomal dominant polycystic kidney disease (ADPKD) is the cause for 5-10% of end stage kidney disease (ESKD) worldwide. Accurate renal prognosis is essential for effective disease management. Investigation of the prognostic value of combining genetic and phenotypic characteristics in a cohort of ADPKD patients is attempted. Method In 66 ADPKD patients (mean age 33 ± 12 years, 32 males) the genetic diagnosis (using targeted Next Generation, tNGS, or Sanger Sequencing or Multiplex ligation-dependent probe amplification, MLPA) and the Mayo Clinic Imaging Category (MCIC) (through Renal Magnetic Resonance Imaging, MRI, for Total Kidney Volume measurement) were assessed. The prediction of ESKD was performed using the Mayo Clinic formula (Irazabal MV et al JASN, 2015). The calculation incorporated variables such as sex, age, e-GFR, and the MCIC. The PROPKD score was derived by considering both phenotypic factors (sex, hypertension and urologic events before the age of 35 years) and genetic data (PKD1-truncating, PKD1-nontruncating and PKD2). Results Adjusted for age, the e-GFR was on average, 26 and 27 ml/min higher in PKD2 patients compared to ADPKD-PKD1-truncating and ADPKD-PKD1-non-truncating patients, respectively (p = 0.001). The median prediction of ESKD for ADPKD-PKD1-truncating, ADPKD-PKD1-non-truncating and PKD2 patients was 22 (11-31) years, 22 (11-34) years and 31 (21-59) years, respectively (NS). In patients categorized as high risk according to PROPKD (score 7-9) the predicted time to ESKD was 16 (9-30) years, for those at intermediate risk (score 4-6), 25 (13-34) years and for those at low risk (score 0-3), 28 (16-55) years (NS). Finally, the PROPKD score showed an inverse correlation to the years of ESKD prediction, as determined by the Mayo Clinic formula; a higher PROPKD score was associated with a shorter prediction period for ESKD (Spearman r = −0.3, p = 0.04). Conclusion Prognosis of renal survival in ADPKD patients requires not only a specific genetic diagnosis but also consideration of the phenotypic data, as incorporated in the PROPKD score, enhancing the accuracy of renal survival prediction.

#2242 mTORi: edging closer to targeted therapy in tuberous sclerosis complex

Abstract Background and Aims Tuberous sclerosis complex (TSC) is an autosomal dominant condition with an estimated incidence of 1 in 6000 births. TSC is caused mostly by mutations in either TSC1 or TSC2 genes, with 70–80% of cases resulting from sporadic mutations; however in 10-15% of cases no mutations are identified. A dysregulation of these genes that encode the hamartin and tuberin proteins, respectively, results in an aberrant signaling of the mammalian target of the rapamycin (mTOR) pathway and subsequent tumor growth. Indeed, the clinical features of TSC are characterized by the proliferation of different types of hamartomas in various organs, including brain, heart, skin, lungs, eyes, bone, kidneys and less frequently pancreas. TSC is mainly diagnosed clinically according to diagnostic criteria with genetic testing performed in cases of diagnostic uncertainty or/and to support the clinic diagnosis. Renal angiomyolipomas (AMLs), observed in more than 80% of patients with TSC, are benign, mostly bilateral tumors, composed of immature smooth muscle cells, abnormal blood vessels and fat cells in variable portions. Their size and the prevalence of their vascular component are directly associated with risk of acute bleeding that in 25% of cases may require embolization or nephrectomy. As a consequence, renal complications are the leading cause of death in adult TSC patients and AML-related surgery is performed in a high percentage of these patients. In the last decade, mTOR inhibitor (mTOR-i) therapy has demonstrated to be a potential alternative to embolization and nephrectomy for managing TSC-AML. The aim of this study was to evaluate over time, potential changes in the relative tissue composition of renal AMLs and their overall size following the initiation of mTOR-i therapy based on MRI measurements. Method From August 2011 to May 2023, 86 potentially eligible adult TSC patients with AML, across a great part of Italy were referred for assessment and monitoring at our center. 14 of these patients were eligible for mTOR-i therapy. An ethics committee approved its use as a compassionate therapy as mTOR-is are not approved as a conventional therapy for renal AMLs in Italy. These patients underwent baseline renal magnetic resonance imaging (MRI) assessment and a regular follow-up with MRI scan every 6-9 months after initiation of therapy. Dose titration was guided by trough levels, side effects and lesion radiological responsiveness on MRI. Results No AML bleeding events were documented during the study. None of the 14 patients on treatment discontinued therapy. Overall, 5 of them (35.7%) required dose adjustments during the course of treatment due to adverse events (40%), sub-optimal trough levels (40%) or minimal radiological response (20%). Radiologic assessment with MRI confirmed a halted growth trend in all treatment-naive cases (100%) and in 64% of them, a regression in AML volume and a reduction of their vascular component within the first year of treatment. Conclusion Our experience confirmed results that emerged from different clinical studies evaluating mTOR inhibition in TSC patients conducted in the last decade. For renal angiomyolipoma, mTOR-i treatment, carefully monitored, fundamentally changed the approach from preventive embolization or even partial nephrectomy to pharmacological treatment; drastically limiting the number of urgent interventional procedures that TSC patients often might undergo. In conclusion, mTOR-i therapy represents a valid and important therapeutic strategy to arrest the growth or regress of renal AMLs.

Socioeconomic deprivation and illness trajectory in the Scottish population after COVID-19 hospitalization

BackgroundThe associations between deprivation and illness trajectory after hospitalisation for coronavirus disease-19 (COVID-19) are uncertain.MethodsA prospective, multicentre cohort study was conducted on post-COVID-19 patients, enrolled either in-hospital or shortly post-discharge. Two evaluations were carried out: an initial assessment and a follow-up at 28–60 days post-discharge. The study encompassed research blood tests, patient-reported outcome measures, and multisystem imaging (including chest computed tomography (CT) with pulmonary and coronary angiography, cardiovascular and renal magnetic resonance imaging). Primary and secondary outcomes were analysed in relation to socioeconomic status, using the Scottish Index of Multiple Deprivation (SIMD). The EQ-5D-5L, Brief Illness Perception Questionnaire (BIPQ), Patient Health Questionnaire-4 (PHQ-4) for Anxiety and Depression, and the Duke Activity Status Index (DASI) were used to assess health status.ResultsOf the 252 enrolled patients (mean age 55.0 ± 12.0 years; 40% female; 23% with diabetes), deprivation status was linked with increased BMI and diabetes prevalence. 186 (74%) returned for the follow-up. Within this group, findings indicated associations between deprivation and lung abnormalities (p = 0.0085), coronary artery disease (p = 0.0128), and renal inflammation (p = 0.0421). Furthermore, patients with higher deprivation exhibited worse scores in health-related quality of life (EQ-5D-5L, p = 0.0084), illness perception (BIPQ, p = 0.0004), anxiety and depression levels (PHQ-4, p = 0.0038), and diminished physical activity (DASI, p = 0.002). At the 3-month mark, those with greater deprivation showed a higher frequency of referrals to secondary care due to ongoing COVID-19 symptoms (p = 0.0438). However, clinical outcomes were not influenced by deprivation.ConclusionsIn a post-hospital COVID-19 population, socioeconomic deprivation was associated with impaired health status and secondary care episodes. Deprivation influences illness trajectory after COVID-19.

Impact on pulmonary, cardiac, and renal function and long-term quality of life after hospitalization for acute respiratory distress syndrome due to COVID-19: Protocol of the Post-COVID Brazil 3 study.

Evidence about long-term sequelae after hospitalization for acute respiratory distress syndrome due to COVID-19 is still scarce. To evaluate changes in pulmonary, cardiac, and renal function and in quality of life after hospitalization for acute respiratory distress syndrome secondary to COVID-19. This will be a multicenter case-control study of 220 participants. Eligible are patients who are hospitalized for acute respiratory distress syndrome due to COVID-19. In the control group, individuals with no history of hospitalization in the last 12 months or long-term symptoms of COVID-19 will be selected. All individuals will be subjected to pulmonary spirometry with a carbon monoxide diffusion test, chest tomography, cardiac and renal magnetic resonance imaging with gadolinium, ergospirometry, serum and urinary creatinine, total protein, and urinary microalbuminuria, in addition to quality-of-life questionnaires. Patients will be evaluated 12 months after hospital discharge, and controls will be evaluated within 90 days of inclusion in the study. For all the statistical analyses, p < 0.05 is the threshold for significance. The primary outcome of the study will be the pulmonary diffusing capacity for carbon monoxide measured after 12 months. The other parameters of pulmonary, cardiac, and renal function and quality of life are secondary outcomes. This study aims to determine the long-term sequelae of pulmonary, cardiac, and renal function and the quality of life of patients hospitalized for acute respiratory distress syndrome due to COVID-19 in the Brazilian population.

Multiparametric Renal Magnetic Resonance Imaging for Prediction and Annual Monitoring of the Progression of Chronic Kidney Disease over Two Years

Multiparametric Renal Magnetic Resonance Imaging for Prediction and Annual Monitoring of the Progression of Chronic Kidney Disease over Two Years

Socioeconomic status and post-covid illness trajectory

Abstract Background The associations between deprivation and illness trajectory after hospitalisation for coronavirus disease-19 (COVID-19) are uncertain. Methods A prospective, multicentre, longitudinal, cohort study involving post-COVID-19 patients enrolled in-hospital or early post-discharge (visit 1) and re-evaluated at 28-60 days post-discharge (visit 2) and in the longer term. Serial research blood tests (biomarkers), digital electrocardiography, and patient-reported outcome measures were obtained at both visits. Novel, multisystem imaging, including chest computed tomography (CT) with pulmonary and coronary angiography, cardiovascular and renal magnetic resonance imaging, was acquired at visit 2. The analysis of primary and secondary outcomes by socioeconomic status was prespecified. The Scottish Index of Multiple Deprivation (SIMD), a small-area measure of social deprivation based on domiciled post code reflecting seven factors including income, employment, education, health, access to services, crime, and housing, and categorized into general population quintiles, was used to measure social deprivation. The EQ-5D-5L, Brief Illness Perception Questionnaire (BIPQ), Patient Health Questionnaire-4 (PHQ-4) for Anxiety and Depression, and the Duke Activity Status Index (DASI) were used to assess health status. Follow-up of clinical outcomes was undertaken using electronic health records. Results Two hundred and fifty-two patients (mean±SD age 55.0 ±12.0 years, body mass index (BMI) 31.3 ±6.9 kg/m2,101 (40%) female, and 59 (23%) with diabetes) were enrolled and had follow-up completed at a median 428 (IQR 385, 538) days. Deprivation status was positively associated with BMI (p=0.0444) and diabetes (p=0.0239). One hundred and eighty-six (74%) patients reattended for investigation 28-60 days post-discharge. Lung ground glass opacity and/or consolidation (p=0.0085), obstructive coronary artery disease (p=0.0128) and renal inflammation (p=0.0421) were associated with deprivation. At 28-60 days post-discharge (n=184), health-related quality of life (EQ-5D-5L utility score, p=0.0084), illness perception, (BIPQ, p=0.0004), anxiety and depression (PHQ-4 score, p=0.0038), physical activity (DASI, p=0.002) and estimated peak oxygen consumption (ml/min/kg) (p=0.002) were worse with greater deprivation. At 3 months (n=252), deprivation status was associated with more referrals to secondary care because of ongoing COVID-19 symptoms (p=0.0438). Clinical outcomes did not associate with deprivation. Conclusion In a post-hospital COVID-19 population, socioeconomic deprivation was associated with impaired health status and secondary care episodes. Deprivation influences illness trajectory after COVID-19.

Application of DKI and IVIM imaging in evaluating histologic grades and clinical stages of clear cell renal cell carcinoma.

To evaluate the value of quantitative parameters derived from diffusion kurtosis imaging (DKI) and intravoxel incoherent motion (IVIM) in differentiating histologic grades and clinical stages of clear cell renal cell carcinoma (ccRCC). A total of 65 patients who were surgically and pathologically diagnosed as ccRCC were recruited in this study. In addition to routine renal magnetic resonance imaging examination, all patients underwent preoperative IVIM and DKI. The corresponding diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion fraction (f), mean diffusivity (MD), kurtosis anisotropy (KA), and mean kurtosis (MK) values were obtained. Independent-samples t-test or Mann-Whitney U test was used for comparing the differences in IVIM and DKI parameters among different histologic grades and clinical stages. The diagnostic efficacy of IVIM and DKI parameters was evaluated using the receiver operating characteristic (ROC) curve. Spearman's correlation analysis was used to separately analyze the correlation of each parameter with histologic grades and stages of ccRCC. The D and MD values were significantly higher in low-grade ccRCC than high-grade ccRCC (all p < 0.001) and in low-stage than high-stage ccRCC (all p < 0.05), and the f value of high-stage ccRCC was lower than that of low-stage ccRCC (p = 0.007). The KA and MK values were significantly higher in low-grade than high-grade ccRCC (p = 0.000 and 0.000, respectively) and in low-stage than high-stage ccRCC (p = 0.000 and 0.000, respectively). The area under the curve (AUC) values of D, D*, f, MD, KA, MK, DKI, and IVIM+DKI values were 0.825, 0.598, 0.626, 0.792, 0.750, 0.754, 0.803, and 0.857, respectively, in grading ccRCC and 0.837, 0.719, 0.710, 0.787, 0.796, 0.784, 0.864, 0.823, and 0.916, respectively, in staging ccRCC. The AUC of IVIM was 0.913 in staging ccRCC. The D, D*, and MD values were negatively correlated with the histologic grades and clinical stages (all p < 0.05), and the KA and MK values showed a positive correlation with histologic grades and clinical stages (all p < 0.05). The f value was also negatively correlated with the ccRCC clinical stage (p = 0.008). Both the IVIM and DKI values can be used preoperatively to predict the degree of histologic grades and stages in ccRCC, and the D and MD values have better diagnostic performance in the grading and staging. Also, further slightly enhanced diagnostic efficacy was observed in the model with combined IVIM and DKI parameters.

Monoexponential, biexponential, stretched-exponential and kurtosis models of diffusion-weighted imaging in kidney assessment: comparison between patients with primary aldosteronism and healthy controls.

This study used various diffusion-weighted imaging (DWI) models (including monoexponential, biexponential, stretched-exponential and kurtosis models) in renal magnetic resonance imaging (MRI) to compare whether there were differences in each diffusion parameter between patients with primary aldosteronism (PA) and healthy volunteers. Twenty-two (female:male, 14:8; age, 48 ± 10years) patients with PA and 22 age- and sex-matched healthy controls (HCs) underwent MRI examinations of the kidneys. The independent-sample t test or the Mann‒Whitney U test was used to detect differences in the diffusion metrics of the kidneys between the two groups. Univariable and multivariable linear regression were applied to analyze the correlations between diffusion parameters and the clinical indicators. The mean diffusivity (MD, p < 0.001) and radial diffusivity (Dr, p < 0.001) values in the medulla were lower in the PA group than in the HC group. The medullary fractional anisotropy (FA, p < 0.001) was higher than that of HCs. The FA (p < 0.001) and axial diffusivity (Da, p < 0.001) values in the cortex were lower in the PA group. The cortical α (anomalous exponent term, p = 0.016) was higher in the PA patients than in the HCs. Linear regression analysis showed that log(plasma aldosterone concentration) and the estimated glomerular filtration rate (eGFR) were correlated with medullary FA. The stretched-exponential model (cortical α) and the kurtosis model (FA, MD and Dr in the medulla and FA and Da in the cortex) showed significant differences between PA patients and healthy volunteers and may have potential for noninvasive renal assessment in PA patients.

Magnetic Resonance Imaging to Diagnose and Predict the Outcome of Diabetic Kidney Disease—Where Do We Stand?

Diabetic kidney disease (DKD) is a major public health problem and its incidence is rising. The disease course is unpredictable with classic biomarkers, and the search for new tools to predict adverse renal outcomes is ongoing. Renal magnetic resonance imaging (MRI) now enables the quantification of metabolic and microscopic properties of the kidneys such as single-kidney, cortical and medullary blood flow, and renal tissue oxygenation and fibrosis, without the use of contrast media. A rapidly increasing number of studies show that these techniques can identify early kidney damage in patients with DKD, and possibly predict renal outcome. This review provides an overview of the currently most frequently used techniques, a summary of the results of some recent studies, and our view on their potential applications, as well as the hurdles to be overcome for the integration of these techniques into the clinical care of patients with DKD.

Assessment of Fasudil on Contrast-Associated Acute Kidney Injury Using Multiparametric Renal MRI.

Aims: To evaluate the utility of fasudil in a rat model of contrast-associated acute kidney injury (CA-AKI) and explore its underlying mechanism through multiparametric renal magnetic resonance imaging (mpMRI). Methods: Experimental rats (n = 72) were grouped as follows: controls (n = 24), CA-AKI (n = 24), or CA-AKI + Fasudil (n = 24). All animals underwent two mpMRI studies (arterial spin labeling, T1 and T2 mapping) at baseline and post iopromide/fasudil injection (Days 1, 3, 7, and 13 respectively). Relative change in renal blood flow (ΔRBF), T1 (ΔT1) and T2 (ΔT2) values were assessed at specified time points. Serum levels of cystatin C (CysC) and interleukin-1β (IL-1β), and urinary neutrophil gelatinase-associated lipocalin (NGAL) concentrations were tested as laboratory biomarkers, in addition to examining renal histology and expression levels of various proteins (Rho-kinase [ROCK], α-smooth muscle actin [α-SMA]), hypoxia-inducible factor-1α (HIF-1α), and transforming growth factor-β1 (TGF-β1) that regulate renal fibrosis and hypoxia. Results: Compared with the control group, serum levels of CysC and IL-1β, and urinary NGAL concentrations were clearly increased from Day 1 to Day 13 in the CA-AKI group (all p < 0.05). There were significant reductions in ΔT2 values on Days 1 and 3, and ΔT1 reductions were significantly more pronounced at all time points (Days 1–13) in the CA-AKI + Fasudil group (vs. CA-AKI) (all p < 0.05). Fasudil treatment lowered expression levels of ROCK-1, and p-MYPT1/MYPT1 proteins induced by iopromide, decreasing TGF-β1 expression and suppressing both extracellular matrix accumulation and α-SMA expression relative to untreated status (all p < 0.05). Fasudil also enhanced PHD2 transcription and inhibition of HIF-1α expression after CA-AKI. Conclusions: In the context of CA-AKI, fasudil appears to reduce renal hypoxia, fibrosis, and dysfunction by activating (Rho/ROCK) or inhibiting (TGF-β1, HIF-1α) certain signaling pathways and reducing α-SMA expression. Multiparametric MRI may be a viable noninvasive tool for monitoring CA-AKI pathophysiology during fasudil therapy.

Individualized everolimus treatment for tuberous sclerosis-related angiomyolipoma promotes treatment adherence and response.

ABSTRACTBackgroundEverolimus is a potential alternative to embolization and nephrectomy for managing tuberous sclerosis complex (TSC)-associated renal angiomyolipoma (AML). In 2016, National Health Service England approved its use through regional centres for renal AML ≥30 mm showing interval growth. Evidence of lesion stabilization or reduction after 6 months is mandated for continuation of long-term treatment.MethodsFrom November 2016 to June 2021, all potentially eligible adult TSC patients with AML across Yorkshire and Humber were referred for assessment and monitoring. Eligible patients underwent baseline renal magnetic resonance imaging (MRI) assessment and a follow-up MRI scan after 6 months on everolimus. Dose titration was guided by trough levels and lesion responsiveness using a new 3D MRI volumetric protocol.ResultsOf 28 patients commencing treatment, 19 tolerated everolimus for >3 months. Overall, 11 patients (40%) discontinued treatment, mostly due to recurrent infections (42%) and allergic reactions (25%). Sixty-eight percent required dose adjustments from the initiating dose (10 mg) due to sub-optimal trough levels (38%), minimal AML response (15%) or adverse events (47%). 3D volumetric assessment confirmed a reduction in AML volume of a pre-selected index lesion in all treatment-naïve cases (n = 14), showing superiority over 2D measurements of lesion diameter.ConclusionIn this cohort, everolimus promoted AML regression in all patients who tolerated the drug for >6 months with stabilization observed over 3 years. Trough levels enabled individual dose titration to maximize responsiveness and minimize side effects. The use of 3D MRI assessment of lesion volume was superior to 2D measurements of lesion diameter in monitoring treatment response.

Quantitative renal magnetic resonance imaging: magnetic resonance urography.

The goal of functional renal imaging is to identify and quantitate irreversible renal damage and nephron loss, as well as potentially reversible hemodynamic changes. MR urography has evolved into a comprehensive evaluation of the urinary tract that combines anatomical imaging with functional evaluation in a single test without ionizing radiation. Quantitative functional MR imaging is based on dynamic contrast-enhanced MR acquisitions that provide progressive, visible enhancement of the renal parenchyma and urinary tract. The signal changes related to perfusion, concentration and excretion of the contrast agent can be evaluated using both quantitative and qualitative measures. Functional evaluation with MR has continued to improve as a result of significant technical advances allowing for faster image acquisition as well as the development of new tracer kinetic models of renal function. The most common indications for MR urography in children are the evaluation of congenital anomalies of the kidney and urinary tract including hydronephrosis and renal malformations, and the identification of ectopic ureters in children with incontinence. In this paper, we review the underlying acquisition schemes and techniques used to generate quantitative functional parameters including the differential renal function (DRF), asymmetry index, mean transit time (MTT), signal intensity versus time curves as well as the calculation of individual kidney glomerular filtration rate (GFR). Visual inspection and semi-quantitative assessment using the renal transit time (RTT) and calyceal transit times (CTT) are fundamental to accurate diagnosis and are used as a basis for the interpretation of the quantitative data. The importance of visual assessment of the images cannot be overstated when analyzing the quantitative measures of renal function.

Will advances in functional renal magnetic resonance imaging translate to the nephrology clinic?

Characterizing structural and tissue abnormalities of the kidney is fundamental to understanding kidney disease. Functional multi-parametric renal magnetic resonance imaging (MRI) is a noninvasive imaging strategy whereby several sequences are employed within a single session to quantify renal perfusion, tissue oxygenation, fibrosis, inflammation, and oedema without using ionizing radiation. In this review, we discuss evidence surrounding its use in several clinical settings including acute kidney injury, chronic kidney disease, hypertension, polycystic kidney disease and around renal transplantation. Kidney size on MRI is already a validated measure for making therapeutic decisions in the setting of polycystic kidney disease. Functional MRI sequences, T1 mapping and apparent diffusion coefficient, can non-invasively quantify interstitial fibrosis and so may have a near-future role in the nephrology clinic to stratify the risk of progressive chronic kidney disease or transplant dysfunction. Beyond this, multi-parametric MRI may be used diagnostically, for example differentiating inflammatory versus ischaemic causes of renal dysfunction, but this remains to be proven. Changes in MRI properties of kidney parenchyma may be useful surrogate markers to use as end points in clinical trials to assess if drugs prevent renal fibrosis or alter kidney perfusion. Large, multi-centre studies of functional renal MRI are ongoing which aim to provide definitive answers as to its role in the management of patients with renal dysfunction.

Comparison of contrast-enhanced magnetic resonance angiography and digital subtraction angiography in the evaluation of renal artery stenosis and detecting of accessory and polar arteries

Objectives: Renal artery stenosis (RAS) is the most common cause of secondary hypertension. RAS may cause renal insufficiency, uncontrolled hypertension and is associated with increased cardiovascular morbidity and mortality. We aimed to evaluate the accuracy of contrast enhanced Flash 3D Renal Magnetic Resonance Angiography (MRA) in the depiction of the RAS also detecting of accessory and polar renal arteries with intraarterial digital subtraction angiography (DSA) still serving as the reference standard. Methods: In this retrospective case-control study, we reviewed contrast enhanced Flash 3D Renal MRA and DSA of 71 patients who were suspected of having RAS and underwent DSA after MRA within 15 days. DSA was accepted as gold standart and the specificity, sensitivity and accuracy of MRA were determined. Results: Overall sensitivity and specificity values of contrast enhanced Flash 3D Renal MRA in detecting stenosis were 96.1% and 76.3% respectively. Conclusions: Contrast enhanced Flash 3D Renal MRA is a reliable noninvasive imaging modality in the diagnosis of RAS.

Perspectives on the Role of Magnetic Resonance Imaging (MRI) for Noninvasive Evaluation of Diabetic Kidney Disease.

Renal magnetic resonance imaging (MRI) techniques are currently in vogue, as they provide in vivo information on renal volume, function, metabolism, perfusion, oxygenation, and microstructural alterations, without the need for exogenous contrast media. New imaging biomarkers can be identified using these tools, which represent a major advance in the understanding and study of the different pathologies affecting the kidney. Diabetic kidney disease (DKD) is one of the most important diseases worldwide due to its high prevalence and impact on public health. However, its multifactorial etiology poses a challenge for both basic and clinical research. Therefore, the use of novel renal MRI techniques is an attractive step forward in the comprehension of DKD, both in its pathogenesis and in its detection and surveillance in the clinical practice. This review article outlines the most promising MRI techniques in the study of DKD, with the purpose of stimulating their clinical translation as possible tools for the diagnosis, follow-up, and monitoring of the clinical impacts of new DKD treatments.

Kidney Segmentation in Renal Magnetic Resonance Imaging - Current Status and Prospects

Magnetic resonance imaging has achieved an increasingly important role in the clinical work-up of renal diseases such chronic kidney disease (CKD). A large panel of parameters have been proposed to diagnose CKD among them total kidney volume (TKV) which recently qualified as biomarker. Volume estimation in renal MRI is based on image segmentation of the kidney and/or its compartments. Beyond volume estimation renal segmentation supports also the quantification of other MR based parameters such as perfusion or filtration. The aim of the present article is to discuss the recent existing literature on renal image segmentation techniques and show today’s limitations of the proposed techniques that might hinder clinical translation. We also provide pointers to open source software related to renal image segmentation.

P0705MULTIPARAMETRIC RENAL MRI IN CHRONIC KIDNEY DISEASE: CHANGES IN CLINICAL AND MRI MEASURES OVER TWO YEARS

Abstract Background and Aims Chronic kidney disease (CKD) progression is currently monitored using estimated GFR (eGFR) and albuminuria but these are relatively crude measures with multiple limitations. Multiparametric renal magnetic resonance imaging (MRI) combines several MR measures into a single scan session, offering the potential to assess severity, progression and response to therapy in CKD in a novel, non-invasive way. Previous studies have focussed on cross-sectional comparisons of MRI and clinical measures. In this study we sought to investigate the ability of MRI variables to predict and monitor progression of CKD over two years. Method Persons with CKD stage 3-4 (eGFR 15-59ml/min/1.732) who had undergone renal biopsy were recruited. Participants underwent multiparametric renal MRI scans on a 3T Philips Ingenia scanner at baseline, one and two years. In addition demographic data, medical history, eGFR and urine protein:creatinine ratio (uPCR) was collected. Multiparametric renal MRI comprised longitudinal relaxation time (T1 using SE-EPI and bFFE readouts), Diffusion Weighted Imaging, renal blood flow (Phase Contrast MRI), renal cortex perfusion (Arterial Spin Labelling), and Blood Oxygen Level Dependent (BOLD) relaxation rate (R2*). CKD progression was defined as participants having a slope in eGFR of -5ml/min/yr or greater over 2 years. Interstitial fibrosis was quantified on renal biopsy samples. Results 22 participants underwent MRI scanning at baseline (7 participants were classified as ‘progressors’ and 15 as ‘stable’), while 13 completed all three scans (4 of whom were ‘progressors’). At baseline, cortex T1 was significantly higher for ‘progressors’ compared to ‘stable’ participants (p=0.02), and renal cortex perfusion was significantly lower (p=0.03). There was no significant difference in total kidney volume (TKV), ADC, renal cortex or medulla R2*, or renal biopsy measures of interstitial fibrosis between ‘progressor’ and ‘stable’ CKD participants. At Year 1 and Year 2 compared to baseline, a decrease in total kidney volume (TKV) was found, with a significantly greater decrease in TKV in the ‘progressor’ group (p=0.04). Over time, T1 increased in the ‘progressor’ group versus baseline, particularly in the cortex which showed a significant difference at year 1 (p=0.034) and year 2 (p=0.053). There was a trend for a reduction in ADC in ‘progressors’ versus stable participants over time. There was no significant change over time or between groups in renal cortex perfusion, renal cortex or medulla T2*, or renal biopsy measures of interstitial fibrosis. Conclusion Our results show that at baseline lower renal cortex perfusion and higher renal cortex T1 were associated with progression of CKD over 2 years suggesting that these MRI parameters may be a predictors of progression. On the other hand, cortex T1, TKV and ADC changed more in ‘progressors’ than in ‘stable’ participants over time (TKV and ADC decreased, T1 increased), suggesting that they may be useful MRI measures to monitor progression. Further studies are required to confirm these findings in a larger cohort of patients before renal MRI can be recommended for clinical use.