Clinical application value of Ultrafast Pulse Wave Velocity in early cardiovascular injury of Immunoglobulin A nephropathy.

AIM: To investigate the application and the related influencing factors of ultrafast pulse wave velocity (ufPWV) in the evaluation of carotid artery elasticity in patients with Immunoglobulin A nephropathy (IgAN). MATERIAL AND METHODS: A total of 156 IgAN patients and 50 healthy individuals were selected as the control group. The ufPWV technique was employed to measure carotid arterial elasticity parameters, including carotid intima-media thickness (cIMT), pulse wave velocity at the beginning of systole (BS-PWV) and pulse wave velocity at the end of systole (ES-PWV). RESULTS: Across the three groups (control group, IgAN patients with normal renal function, and IgAN patients with renal dysfunction) there was an increasing trend observed in cIMT, BS-PWV, and ES-PWV. Additionally, ES-PWV exhibited higher sensitivity than BS-PWV. Correlation analysis revealed that BS-PWV and ES-PWV were positively correlated with age, body mass index (BMI), systolic blood pressure (SBP), high-sensitivity C-reactive protein (hs-CRP), creatinine (Cr), blood urea nitrogen (BUN), and uric acid (UA) and negatively correlated with estimated glomerular filtration rate (eGFR). CONCLUSION: The ufPWV technique allows for the rapid and direct measurement of arterial elasticity parameters in the neck and represents a novel approach for the early diagnosis and quantitative assessment of arterial stiffness risk in IgAN patients.

Renal and cardiovascular prognostic significance of echocardiographic early diastolic mitral annular velocity in IgA nephropathy.

In chronic kidney disease (CKD), as in IgA nephropathy (IgAN), cardiovascular (CV) mortality and morbidity are many times higher than in the general population, and diastolic dysfunction (LVDD) has prognostic significance as well. Tissue Doppler Echocardiography (TDI) is another method for measuring myocardial contractility and determining diastolic dysfunction. 79 IgAN patients (age 46 ± 11 years) with CKD stages 1-3 were investigated and followed for 70 ± 28.7 months. Doppler echocardiography was used to measure the E (early) and A (late) waves, as well as the E wave deceleration time (EDT) during mitral inflow. TDI was used to measure early (Ea) and late (Aa) diastolic velocities (lateral and septal basal wall fragment average). From these, we calculated the E/Ea and Ea/Aa ratios. The primary combined endpoints were total mortality, major CV events, and end-stage renal disease, and the secondary endpoints were cardiovascular or renal (eGFR decreased below 15 ml/min/1.73 m2 or renal replacement therapy was started). Patients with decreased Ea (< 13 cm/s) had significantly more endpoints (20/42 vs. 3/37; p = 0.001) than patients with higher Ea (≥ 13 cm/s). The secondary renal endpoints were also significantly higher (p = 0.004). In a multivariate model, the eGFR showed independent correlation with the E/A ratio (r = 0.466; p < 0.01), EDT (r = - 0.270; p < 0.01), Ea/Aa ratio (r = 0.455; p < 0.01), and decreased Ea (r = 0.544; p < 0.01). Independent factors influencing Ea were only EDT by uni- and multivariate regression but age and albuminuria by logistic regression. Decreased Ea measured by TDI seems to be an eligible factor to predict the prognosis of IgA nephropathy. The decreased Ea may be a helpful parameter to identify high-risk CKD patients.

Development of a novel combined nomogram model integrating deep learning radiomics to diagnose IgA nephropathy clinically.

This study aimed to develop and validate a combined nomogram model based on superb microvascular imaging (SMI)-based deep learning (DL), radiomics characteristics, and clinical factors for noninvasive differentiation between immunoglobulin A nephropathy (IgAN) and non-IgAN.We prospectively enrolled patients with chronic kidney disease who underwent renal biopsy from May 2022 to December 2022 and performed an ultrasound and SMI the day before renal biopsy. The selected patients were randomly divided into training and testing cohorts in a 7:3 ratio. We extracted DL and radiometric features from the two-dimensional ultrasound and SMI images. A combined nomograph model was developed by combining the predictive probability of DL with clinical factors using multivariate logistic regression analysis. The proposed model's utility was evaluated using receiver operating characteristics, calibration, and decision curve analysis. In this study, 120 patients with primary glomerular disease were included, including 84 in the training and 36 in the test cohorts. In the testing cohort, the ROC of the radiomics model was 0.816 (95% CI:0.663-0.968), and the ROC of the DL model was 0.844 (95% CI:0.717-0.971). The nomogram model combined with independent clinical risk factors (IgA and hematuria) showed strong discrimination, with an ROC of 0.884 (95% CI:0.773-0.996) in the testing cohort. Decision curve analysis verified the clinical practicability of the combined nomogram. The combined nomogram model based on SMI can accurately and noninvasively distinguish IgAN from non-IgAN and help physicians make clearer patient treatment plans.

A novel clinical-radiomic nomogram for the crescent status in IgA nephropathy.

Objective: We used machine-learning (ML) models based on ultrasound radiomics to construct a nomogram for noninvasive evaluation of the crescent status in immunoglobulin A (IgA) nephropathy. Methods: Patients with IgA nephropathy diagnosed by renal biopsy (n=567) were divided into training (n=398) and test cohorts (n=169). Ultrasound radiomic features were extracted from ultrasound images. After selecting the most significant features using univariate analysis and the least absolute shrinkage and selection operator algorithm, three ML algorithms were assessed for final radiomic model establishment. Next, clinical, ultrasound radiomic, and combined clinical-radiomic models were compared for their ability to detect IgA crescents. The diagnostic performance of the three models was evaluated using receiver operating characteristic curve analysis. Results: The average area under the curve (AUC) of the three ML radiomic models was 0.762. The logistic regression model performed best, with AUC values in the training and test cohorts of 0.838 and 0.81, respectively. Among the final models, the combined model based on clinical characteristics and the Rad score showed good discrimination, with AUC values in the training and test cohorts of 0.883 and 0.862, respectively. The decision curve analysis verified the clinical practicability of the combined nomogram. Conclusion: ML classifier based on ultrasound radiomics has a potential value for noninvasive diagnosis of IgA nephropathy with or without crescents. The nomogram constructed by combining ultrasound radiomic and clinical features can provide clinicians with more comprehensive and personalized image information, which is of great significance for selecting treatment strategies.

Evaluating the renal mild tubulointerstitial damage and renal function in IgAN patients: a comparative study based on diffusion kurtosis imaging and diffusion tensor imaging.

OBJECTIVE: To compare the performance of 3.0 T magnetic resonance diffusion kurtosis imaging (DKI) and diffusion tensor imaging (DTI) in evaluation of the degree of tubulointerstitial damage and renal function in Immunoglobulin A Nephropathy (IgAN) patients. METHODS: Both DKI and DTI were performed in 40 IgAN patients and 17 healthy volunteers. IgAN patients were divided into two groups according to tubulointerstitial lesion score: Mild injury group, n = 24; Moderate-severe injury group, n = 16. DKI characteristic parameters [mean kurtosis (MK), axial kurtosis (Ka), radial kurtosis (Kr)] and DTI parameters [fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (Da), radial diffusivity (Dr)] of renal cortex and medulla were measured and compared among different groups. Correlations between DKI, DTI parameters and clinicopathological characteristics were assessed. Diagnostic performance of DKI and DTI to evaluate tubulointerstitial damage of IgAN was compared. RESULTS: Cortical MK, Kr, Da and parenchymal Ka significantly differed among three groups (P < 0.05). Cortical MK, Kr, Ka were negatively correlated with estimated glomerular filtration rate (eGFR) (MK: r = - 0.613; Kr: r = - 0.539; Ka: r = - 0.664) and positively correlated with tubulointerstitial lesion score (MK: r = 0.655; Kr: r = 0.577; Ka: r = 0.661) (all P < 0.001). Lower correlation coefficient was found among cortical FA, MD, Dr and eGFR, tubulointerstitial lesion score (all|r|< 0.350). The AUCs of DKI and DTI parameters for differentiating Mild injury group from control group were (cortical MK 0.822, cortical Ka 0.816; cortical FA 0.515, cortical MD 0.714) and for differentiating Mild injury group from Moderate-severe injury group were (cortical MK 0.813, cortical Ka 0.831; medulla FA 0.784, medulla MD 0.586). CONCLUSION: Compared with DTI, DKI was more sensitive and accurate to probe the renal function and the tubulointerstitial damage of IgAN, especially the mild tubulointerstitial damage.

Noninvasive Assessment of the Renal Function, Oxford Classification and Prognostic Risk Stratification of IgAN by Using Intravoxel Incoherent Motion Diffusion-Weighted Imaging and Blood Oxygenation Level-Dependent MRI.

BACKGROUND: Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. Oxford classification including mesangial hypercellularity (M), endothelial hypercellularity (E), segmental sclerosis (S), interstitial fibrosis/tubular atrophy (T), and crescent (C) were recommended to predict the prognosis of IgAN. PURPOSE: To explore whether multiparametric magnetic resonance imaging (MRI) can be applied to assess the renal function, Oxford classification, and risk of progression to end-stage kidney disease within 5 years of IgAN. STUDY TYPE: Prospective. POPULATION: A total of 46 patients with pathologically confirmed IgAN and 20 healthy volunteers. FIELD STRENGTH/SEQUENCE: A 3-T, blood oxygenation level-dependent (BOLD)-MRI, intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI). ASSESSMENT: Two radiologists measured the cortex and medulla T2*, apparent diffusion coefficient (ADC), true diffusion (Dt), pseudo-diffusion (Dp), perfusion fraction (fp). All participants were divided into three groups: group 1, healthy volunteers; group 2, patients with estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 ; group 3, patients with eGFR <60 mL/min/1.73 m2 . Or two groups: group A, 5-year risk scores ≤10% and group B, 5-year risk scores >10%. STATISTICAL TESTS: Intraclass correlation coefficient, one-way analysis of variance, least-significant difference, Student's t-test, Pearson product-moment correlation, Spearman's rank correlation, and receiver operating characteristics (ROC) with the area under the curve (AUC). A P value <0.05 was considered statistically significant. RESULTS: Except for cortical Dp, all other MRI parameters showed significant differences between group 1 and group 2. None of the MRI parameters showed a significant correlation with M, E, or C scores. Cortical T2*, Dt, fp, and medullary Dt and fp showed low-to-moderate significant correlations with S scores. Except for cortical and medullary Dp, all other MRI parameters were significantly correlated with T scores. Cortical Dt showed the largest AUC for differentiating group A from group B (AUC = 0.927) and T0 from T1/T2 (AUC = 0.963). DATA CONCLUSION: Imaging by IVIM-DWI and BOLD-MRI could facilitate noninvasive assessment of the renal function, Oxford classification, and prognostic risk of IgAN patients. EVIDENCE LEVEL: 2. TECHNICAL EFFICACY: Stage 3.

Anomalous kinetics of galactose-deficient IgA incurring nephropathy revealed by cross-scale optical imaging.

IgA nephropathy (IgAN) is the most common glomerulonephritis, characterized by the presence of predominant IgA deposits in the mesangium. Deposition of pathogenic IgA in kidney tissue is a fundamental initiating process that has not been fully studied. Here, we employed optical imaging to directly visualize kidney deposition of IgA with optimized spatial and temporal resolution in BALB/c nude mice. Real-time fluorescence imaging revealed that IgA isolated from patients with IgAN preferentially accumulated in the kidneys, compared with IgA purified from healthy individuals. There was no difference in the distribution of either IgA preparation by the liver. Photoacoustic computed tomography dynamically demonstrated and quantified the enhanced retention of pathological IgA in the kidney cortex. Photoacoustic microscopy tracked IgA deposition in the glomeruli with a resolution down to three microns in a mouse model. Notably, longitudinal fluorescent imaging revealed that galactose-deficient IgA (Gd-IgA), which was elevated in the circulation of patients with IgAN, persisted in the kidney for longer than two weeks, and stable deposition of Gd-IgA induced kidney impairment, including albuminuria and mesangial proliferation. Thus, our study highlights that the aberrant kidney depositional kinetics of Gd-IgA is involved in the pathogenesis of IgAN. Hence, cross-scale optical imaging has potential applications in assessing immune-mediated kidney diseases and uncovering underlying mechanisms of disease.

Noninvasive evaluation of IgA nephropathy fibrosis using Doppler ultrasound.

In this study, we aimed to explore the clinical value of routine color ultrasound parameters in the evaluation of tubular atrophy and interstitial fibrosis (TA/IF) in IgA nephropathy (IgAN). We enrolled 725 patients with IgAN who underwent renal biopsy at the First Affiliated Hospital of Anhui Medical University between January 2019 and May 2022. Examinations were performed to measure the routine ultrasound renal parameters and renal biopsy was done within next three days. Univariate and multivariate analyses were used to determine the correlates and the independent predictors of TA/IF. Simultaneously, a nomogram based on risk indicators was created to predict TA/IF. Univariate and multivariate analyses showed that sex (p < 0.001, OR = 2.538, 95%CI: 1.739-3.734), renal length (p < 0.001, OR = 0.927, 95%CI: 0.905-0.95), resistive index of main renal artery (p = 0.037, OR = 1.891, 95%CI: 1.027-3.426), peak systolic velocity of segmental renal artery (p = 0.58, OR = 0.975, 95%CI: 0.399-0.841), and cortex echogenicity (p < 0.001, OR = 3.448, 95%CI: 2.382-5.018) were independent predictors of TA/IF in IgAN nomograms, with a good C-index of 0.765 (95%CI = 0.727-0.803). Analyses of the calibration charts show that nomograms have good performance and clinical applicability. In our study, renal color ultrasound parameters correlated well with TA/IF in IgAN. By establishing a conventional color ultrasound prediction model, we can accurately gauge the extent of TA/IF in patients with IgAN for clinical applications.

Contrast-enhanced ultrasonography for assessing histopathology in pediatric immunoglobulin A nephropathy and Henoch-Schönlein purpura nephritis.

BACKGROUND: Glomerular disease, including immunoglobulin A nephropathy (IgAN) and Henoch-Schönlein purpura nephritis, is one of the most common kidney diseases in children. The diagnosis of these diseases depends on pathological biopsy, although this procedure is seriously limited by its invasive and high-risk nature. OBJECTIVE: To investigate the potential of contrast-enhanced ultrasonography (CEUS) for evaluating the histopathological severity of IgAN and Henoch-Schönlein purpura nephritis (HSPN). MATERIALS AND METHODS: We investigated a total of 13 children with IgAN and 12 children with HSPN confirmed by renal histopathology. We reevaluated the pathological lesions of the children according to the Oxford classification and the Lee grading system and then all the children underwent CEUS. Using SonoLiver software, we constructed time-intensity curves of CEUS for regions of interest in the renal cortex. We analyzed CEUS quantitative parameters for IgAN and HSPN and used Spearman correlation analysis to examine the correlation between CEUS parameters and clinicopathological indexes in the study cohort. RESULTS: The CEUS parameters rise time (RT) and time to peak (TTP) were significantly higher in children with Lee grade IV than in those with Lee grades II or III. Spearman correlation analysis revealed a positive correlation between rise time and time to peak with Lee grade in the overall cohort of children, and a positive correlation between rise time and time to peak and severity of crescents in the Oxford classification scoring system. CONCLUSION: Contrast-enhanced US may be used as a noninvasive imaging technique to evaluate the severity of renal pathology and formation of crescents in children with IgAN and HSPN.

IgA Nephropathy in a Patient With Metastatic Carcinoma of Unknown Primary: Findings on 18F-FDG PET/MRI.

ABSTRACT: A 35-year-old man with mesenteric metastases of unknown primary was referred for 18F-FDG PET/MRI. The images demonstrated that FDG accumulated in the chest, abdomen, bilateral kidneys, and external genitalia. Renal and testicular metastases were suspected. The primary tumor was still not found. In addition, kidney biopsy findings indicated a diagnosis of IgA nephropathy.

Color Doppler Ultrasound and Hemodynamics for Evaluating Graft Dysfunction in Recurrent Immunoglobulin A Nephropathy.

BACKGROUND The aim of this study was to investigate the diagnostic and prognostic utility of color Doppler ultrasound for graft dysfunction in recurrent immunoglobulin A nephropathy (IgAN). MATERIAL AND METHODS We selected a series of 78 biopsies diagnostic of recurrent IgAN following living-donor transplantation from July 2004 to January 2019. Based on Lee's classification, Doppler parameters in different degrees of histopathological injury were retrospectively analyzed. RESULTS The 4-year cumulative graft survival rate after biopsy was 66.3%, and the difference among the Kaplan-Meier curves of Lee's classification (P<0.01) was significant. Doppler parameters showed that echo enhancement, decreasing blood flow distribution, decreasing end-diastolic velocity (EDV) of the main renal artery (MRA), segmental renal atery (SRA) and interlobar renal artery (IRA), and an elevated resistance index (RI) of the arcuate renal artery (ARA) were significantly different among grades I-V of Lee's classification (P<0.05). Logistic multivariate analysis indicated that echo enhancement (HR 13.6, 95% CI 2.7-68.4) and decreasing EDV of the SRA (HR 1.1 for a 1-cm/s, 95% CI 1.0-1.2) were independent predictors of severe injury (IV-V). The ROC curve fitted by echo enhancement and decreasing EDV of the SRA had an area under the curve of 0.87. The cutoff was 17.5 cm/s (decreasing EDV of the SRA) without echo enhancement. The sensitivity and specificity were 72.2% and 91.7%, respectively. CONCLUSIONS Color Doppler ultrasound successfully evaluated the graft dysfunction in recurrent IgAN; a decreasing EDV of the SRA indicated severe histopathological injury and poor prognosis.

Preliminary study on the application of renal ultrasonography radiomics in the classification of glomerulopathy.

BACKGROUND: The aim of this study was to investigate the potential use of renal ultrasonography radiomics features in the histologic classification of glomerulopathy. METHODS: A total of 623 renal ultrasound images from 46 membranous nephropathy (MN) and 22 IgA nephropathy patients were collected. The cases and images were divided into a training group (51 cases with 470 images) and a test group (17 cases with 153 images). A total of 180 dimensional features were designed and extracted from the renal parenchyma in the ultrasound images. Least absolute shrinkage and selection operator (LASSO) logistic regression was then applied to these normalized radiomics features to select the features with the highest correlations. Four machine learning classifiers, including logistic regression, a support vector machine (SVM), a random forest, and a K-nearest neighbour classifier, were deployed for the classification of MN and IgA nephropathy. Subsequently, the results were assessed according to accuracy and receiver operating characteristic (ROC) curves. RESULTS: Patients with MN were older than patients with IgA nephropathy. MN primarily manifested in patients as nephrotic syndrome, whereas IgA nephropathy presented mainly as nephritic syndrome. Analysis of the classification performance of the four classifiers for IgA nephropathy and MN revealed that the random forest achieved the highest area under the ROC curve (AUC) (0.7639) and the highest specificity (0.8750). However, logistic regression attained the highest accuracy (0.7647) and the highest sensitivity (0.8889). CONCLUSIONS: Quantitative radiomics imaging features extracted from digital renal ultrasound are fully capable of distinguishing IgA nephropathy from MN. Radiomics analysis, a non-invasive method, is helpful for histological classification of glomerulopathy.

Renal resistive index in IgA nephropathy and renal scleroderma vasculopathy.

BACKGROUND: Renal Ultra-Sound (US) and Doppler US provide measurements which reflect changes in renal and systemic haemodynamic. The renal resistive index (RRI), obtained through the Doppler spectrum analysis of renal small arteries, is altered in several pathologic conditions. Glomerulonephritis cause minor RRI changes, while renal scleroderma vasculopathy (RSV) leads to significant RRI modifications. The aim of our study was to assess RRI in IgA nephropathy (IgAN) and RSV in a retrospective observational study and to investigate determinants of the RRI in these groups of patients. METHODS: We enrolled 61 IgAN patients [23 female, median age 41 (33-58) years] and 80 SSc patients [71 female, median age 52 (43-60) years]. RRI was evaluated in all patients at the time of enrolment. Laboratory tests and clinical assessment were evaluated in all patients. RESULTS: IgAN patients showed lower RRI values than RSV patients [0.70 (0.65-0.73) vs 0.66 (0.62-0.72), p < 0.01], while no significant difference in longitudinal length was observed. Median age was significantly lower in IgAN patients than in RSV patients [41 (33-58) vs 52 (43-60), p < 0.05] while IgAN patients showed a higher prevalence of high blood pressure than RSV patients (39.3% vs 13.8%, p < 0.01). The multiple regression analysis, weighted for age, showed that RRI inversely correlates with estimated glomerular filtration rate (ß coefficient = -0.524, p < 0.0001). CONCLUSION: Higher RRI were found in RSV patients than IgAN patients. IgAN is characterized mainly by glomerular injury, not leading to major RRI changes.

Pathological application of carbocyanine dye-based multicolour imaging of vasculature and associated structures.

Simultaneous visualisation of vasculature and surrounding tissue structures is essential for a better understanding of vascular pathologies. In this work, we describe a histochemical strategy for three-dimensional, multicolour imaging of vasculature and associated structures, using a carbocyanine dye-based technique, vessel painting. We developed a series of applications to allow the combination of vessel painting with other histochemical methods, including immunostaining and tissue clearing for confocal and two-photon microscopies. We also introduced a two-photon microscopy setup that incorporates an aberration correction system to correct aberrations caused by the mismatch of refractive indices between samples and immersion mediums, for higher-quality images of intact tissue structures. Finally, we demonstrate the practical utility of our approach by visualising fine pathological alterations to the renal glomeruli of IgA nephropathy model mice in unprecedented detail. The technical advancements should enhance the versatility of vessel painting, offering rapid and cost-effective methods for vascular pathologies.

Potential value of three-dimensional ultrasonography in diagnosis of diabetic nephropathy in Chinese diabetic population with kidney injury.

BACKGROUND: To explore the potential value of three-dimensional ultrasonography (3DUS) and contrast-enhanced ultrasound (CEUS) in the diagnosis of diabetic nephropathy (DN) in Chinese diabetic patients with kidney injury. METHODS: Patients with type 2 diabetes mellitus and kidney injury in our hospital were enrolled, and the clinical characteristics as well as the laboratory data of patients were collected; 3DUS and CEUS were used to evaluate the morphological structure and blood perfusion of kidneys. Eligible patients were categorized into two groups based on renal biopsy results: DN group and non-diabetic renal diseases (NDRD) group. Correlation analysis and logistic regression analysis were applied to identify the risk factors of DN development. RESULTS: A total of 115 patients aged from 24 to 78 years old were recruited in the experiment, of which 64 patients (55.65%) and 51 patients (44.35%) were in the DN group and NDRD group, respectively. After correction to CKD stage, BMI and right kidney volume index were retained to identify patients with DN. The ROC of the logistic regression model had an AUC of 0.703 (95% CI: 0.591-0.815) and it was higher than both indicators. CONCLUSION: 3DUS has potential value in the diagnosis of diabetic nephropathy in Chinese diabetic population with kidney injury and may act as an auxiliary diagnosis for DN. More prospective and well-designed studies with larger samples are needed to verify the result.

Shear wave elastography findings in Immunoglobulin A Nephropathy patients: is it more specific and sensitive for interstitial fibrosis or interstitial fibrosis/tubular atrophy?

Background: Prediction of prognosis in Immunoglobulin A Nephropathy (IgAN) and taking appropriate precautions may reduce annual incidence of chronic kidney disease. This may be possible by close follow-up for the development and progression of interstitial fibrosis (IF) or interstitial fibrosis/tubular atrophy (IFTA) in IgAN patients.Aim: To investigate whether Young's elastic modulus (YM) which measured shear wave elastography (SWE) might be used for follow-up of IF or IFTA in IgAN patients.Methods: Prospective study was approved by Human Research Ethics Committee. Group 1 consisted of patients with IgAN. Group 2 consisted of healthy control participants. Young's elastic modulus which is a value of stiffness along with longitudinal stiffness was used to evaluate tissue elasticity. Specificity, sensitivity, positive predictive value (PPV) of YM for the presence of IF and IFTA were evaluated.Results: Group 1 consisted of 30 participants, and group 2 consisted of 32 participants. Sensitivity and specificity of SWE to diagnose presence of IF for YM > 15 kPa were 89% and 90%, respectively. PPV among the ones whom IF was diagnosed by YM >15 kPa was 91%. Sensitivity and specificity of SWE to diagnose presence of IFTA for YM > 15 were 65% and 51%, respectively. PPV among the ones whom IFTA was diagnosed by YM >15 kPa was 78.1%.Conclusions: YM which measured SWE is highly specific and sensitive in the diagnosis of IF, but not for IFTA in IgAN patients. Therefore, progression for IF in IgAN may be followed by SWE.

Multiparametric Quantitative MRI for the Detection of IgA Nephropathy Using Tomoelastography, DWI, and BOLD Imaging.

OBJECTIVES: The aim of this study was to noninvasively evaluate changes in renal stiffness, diffusion, and oxygenation in patients with chronic, advanced stage immunoglobulin A nephropathy (IgAN) by multiparametric magnetic resonance imaging using tomoelastography, diffusion-weighted imaging (DWI), and blood oxygen level-dependent (BOLD) imaging. MATERIALS AND METHODS: In this prospective study, 32 subjects (16 patients with biopsy-proven IgAN and 16 age- and sex-matched healthy controls) underwent multifrequency magnetic resonance elastography with tomoelastography postprocessing at 4 frequencies from 40 to 70 Hz to generate shear wave speed (meter per second) maps reflecting tissue stiffness. In addition, DWI and BOLD imaging were performed to determine the apparent diffusion coefficient in square millimeter per second and T2* relaxation time in milliseconds, respectively. Regions including the entire renal parenchyma of both kidneys were analyzed. Areas under the receiver operating characteristic (AUCs) curve were calculated to test diagnostic performance. Clinical parameters such as estimated glomerular filtration rate and protein-to-creatinine ratio were determined and correlated with imaging findings. RESULTS: Success rates of tomoelastography, DWI, and BOLD imaging regarding both kidneys were 100%, 91%, and 87%, respectively. Shear wave speed was decreased in IgAN (-21%, P < 0.0001), accompanied by lower apparent diffusion coefficient values (-12%, P = 0.004). BOLD imaging was not sensitive to IgAN (P = 0.12). Tomoelastography detected IgAN with higher diagnostic accuracy than DWI (area under the curve = 0.9 vs 0.8) and positively correlated with estimated glomerular filtration rate (r = 0.66, P = 0.006). CONCLUSIONS: Chronic, advanced stage IgAN is associated with renal softening and restricted water diffusion. Tomoelastography is superior to DWI and BOLD imaging in detecting IgAN.

Combined Acoustic Radiation Force Impulse and Conventional Ultrasound in the Quantitative Assessment of Immunoglobulin a Nephropathy.

We investigated the value of combined acoustic radiation force impulse (ARFI) imaging and conventional ultrasound (US) in identifying renal histopathological fibrosis with immunoglobulin A nephropathy. A total of 146 patients with immunoglobulin A nephropathy, pathologically confirmed by renal biopsy were grouped according to Oxford classification and Katafuchi grading, were included in the test group, and 39 healthy volunteers were included in the control group. Receiver operating characteristic (ROC) curves were constructed to compare the diagnostic accuracy of ARFI, renal lengths, parenchymal thicknesses and interlobular arterial resistance index (RI) and their combinations in identifying Katafuchi grading at renal biopsy. Shear wave velocity (SWV), renal length, renal parenchyma thickness and the interlobular arterial RI were correlated with Katafuchi grading, mesangial hypercellularity (M) and tubular atrophy/interstitial fibrosis (T) (r = -0.504 to -0.407, p < 0.01) but were not correlated with endocapillary hypercellularity (E) or segmental glomerulosclerosis (S). The area under the curves of SWV value + conventional US index (renal length, renal parenchyma thickness and interlobular arterial RI) was higher than those of the SWV value or of the conventional US index alone. The combination of ARFI imaging and conventional US can improve the diagnostic performance in quantitative evaluation pathologic damage in patients with immunoglobulin A nephropathy.

Diffusional kurtosis imaging in assessing renal function and pathology of IgA nephropathy: a preliminary clinical study.

AIM: To evaluate renal fibrosis in immunoglobulin A nephropathy (IgAN) using diffusion kurtosis imaging (DKI). MATERIALS AND METHODS: Twenty patients with biopsy-proven IgAN were enrolled. DKI was performed on a clinical 3 T magnetic resonance imaging (MRI) system, and region-of-interest measurements were conducted to determine mean kurtosis (K), mean diffusivity (D), and apparent diffusion coefficient (ADC) of the kidney cortex. Renal biopsy specimens were scored based on the severity of renal fibrosis. The associations between the DKI data and clinicopathological parameters were investigated. RESULTS: Both the K and ADC were not only well correlated with the estimated glomerular filtration rate, but also significantly associated with the pathological scores of fibrosis, including the glomerular sclerosis index (K: r=0.759, p<0.001; ADC: r=-0.636, p=0.003) and the percentage of tubular atrophy and interstitial fibrosis (K: r=0.767, p<0.001; ADC: r=-0.702, p=0.001). Further receiver operating characteristic analysis showed that K demonstrated better diagnostic performance in discriminating severe glomerulosclerosis (area under curve [AUC] 0.970, sensitivity 81.8%, specificity 100%), and ADC displayed better capabilities in identifying severe tubular atrophy/interstitial fibrosis (AUC 0.976, sensitivity 100%, specificity 92.9%). CONCLUSION: This DKI method can be used to detect renal fibrosis in IgAN in a non-invasive manner and may provide additional information for characterisation and surveillance.

Cilostazol-induced acute tubulointerstitial nephritis accompanied by IgA nephropathy: a case report.

BACKGROUND: Cilostazol is an antiplatelet drug that is widely prescribed for the prevention of secondary stroke. Adverse reactions to cilostazol include headaches, palpitations, and diarrhea. Little is known about the nephrotoxicity of cilostazol, such as acute kidney injury. We report a biopsy-proven case of diffuse tubulointerstitial nephritis induced by cilostazol. CASE PRESENTATION: A 69-year-old woman prescribed cilostazol was hospitalized for acute kidney injury. On admission, her renal function deteriorated, with an increased serum creatinine level. Urinalysis showed hematuria, proteinuria, and hyper-beta2-microglobulinuria. A renal biopsy revealed diffuse tubulointerstitial nephritis associated with IgA nephropathy, and gallium-67 scintigraphy showed uptake in the bilateral kidneys. A drug lymphocyte stimulation test for cilostazol was positive, and the patient was diagnosed with cilostazol-induced acute tubulointerstitial nephritis. Despite discontinuation of cilostazol, her renal function rapidly worsened and steroid pulse therapy was initiated, followed by oral high-dose glucocorticoid therapy. After steroid treatment, her serum creatinine level normalized in parallel with urine beta2-microglobulin. CONCLUSION: Cilostazol can induce acute tubulointerstitial nephritis.