Resting-state MRI reveals spontaneous physiological fluctuations in the kidney and tracks diabetic nephropathy in rats.

The kidneys maintain fluid-electrolyte balance and excrete waste in the presence of constant fluctuations in plasma volume and systemic blood pressure. The kidneys perform these functions to control capillary perfusion and glomerular filtration by modulating the mechanisms of autoregulation. An effect of these modulations are spontaneous, natural fluctuations in glomerular perfusion. Numerous other mechanisms can lead to fluctuations in perfusion and flow. The ability to monitor these spontaneous physiological fluctuations in vivo could facilitate the early detection of kidney disease. The goal of this work was to investigate the use of resting-state magnetic resonance imaging (rsMRI) to detect spontaneous physiological fluctuations in the kidney. We performed rsMRI of rat kidneys in vivo over 10 min, applying motion correction to resolve time series in each voxel. We observed spatially variable, spontaneous fluctuations in rsMRI signal between 0 and 0.3 Hz, in frequency bands associated with autoregulatory mechanisms. We further applied rsMRI to investigate changes in these fluctuations in a rat model of diabetic nephropathy. Spectral analysis was performed on time series of rsMRI signals in the kidney cortex and medulla. The power from spectra in specific frequency bands from the cortex correlated with severity of glomerular pathology caused by diabetic nephropathy. Finally, we investigated the feasibility of using rsMRI of the human kidney in two participants, observing the presence of similar, spatially variable fluctuations. This approach may enable a range of preclinical and clinical investigations of kidney function and facilitate the development of new therapies to improve outcomes in patients with kidney disease.NEW & NOTEWORTHY This work demonstrates the development and use of resting-state MRI to detect low-frequency, spontaneous physiological fluctuations in the kidney consistent with previously observed fluctuations in perfusion and potentially due to autoregulatory function. These fluctuations are detectable in rat and human kidneys, and the power of these fluctuations is affected by diabetic nephropathy in rats.

Predicting Osteoporotic Fracture in Patients With Early-Stage Diabetic Kidney Disease Using a Radiomic Model: A Longitudinal Cohort Study.

OBJECTIVE: There is an urgent need for effective predictive strategies to accurately evaluate the risk of fragility fractures in elderly patients in the early stages of diabetic kidney disease (DKD). METHODS: This longitudinal cohort study included 715 older patients in the early stages of DKD diagnosed between January 2015 and August 2019. Patients were randomly allocated to a training cohort (n = 499) and a validation cohort (n = 216). The least absolute shrinkage and selection operator method was used to select key features for dual-energy x-ray absorptiometry-based radiomic analysis. A radiomic model was constructed using Cox proportional hazards regression. The performance of the radiomic model was compared with that of traditional fracture assessment tools through a receiver operating characteristic curve, calibration curve, and decision curve analysis. RESULTS: Over a mean follow-up period of 4.72 ± 1.60 years, 65 participants (9.09%) experienced incident fragility fractures. Seventeen features were ultimately selected to create the radiomic model. The calibration plots of this model demonstrated satisfactory agreement between the observed and predicted outcomes. Moreover, the radiomic model outperformed traditional fracture assessment tools in both the training and validation cohorts according to the area under the receiver operating characteristic curve and decision curve analysis. CONCLUSIONS: The novel radiomic model has demonstrated a more effective prediction of fragility fracture in elderly patients in the early stages of DKDcompared to traditional fracture assessment tools.

Quantitative assessment of early kidney injury using high frame rate contrast-enhanced ultrasonography in a rabbit model of diabetic nephropathy.

AIM: To explore benefits of high-frame-rate contrast-enhanced ultrasonography (H-CEUS) for early kidney injury in a rabbit model of diabetic nephropathy (DN). METHODS: Diabetic rabbits were induced with alloxan administration and split into 2 groups with or without urinary microalbuminuria after a fatty and sugary diet: diabetic rabbits with nephropathy (Group A) and diabetic rabbits without nephropathy (Group B). The control group (Group C) comprised healthy rabbits. Renal H-CEUS and conventional CEUS (C-CEUS) imaging were conducted. Serum creatinine (SCR), blood urea nitrogen (BUN) and urinary microalbuminuria were measured. RESULTS: SCR and BUN levels were barely changed in Groups B and C (p>0.05), whereas Group A exhibited a rise (p<0.05). Perfusion parameters of the two CEUS modalities showed reduced peak intensity (PI) and ascending slope (AS) and elevated area under the curve (AUC) and time to peak (TTP) in Group A versus Group B (p<0.05) and Group B versus Group C (p<0.05). The arrival time (AT) and descending slope (DS) exhibited little difference among the three groups. H-CEUS had a stronger correlation of perfusion parameters with SCR and BUN than C-CEUS. CONCLUSIONS:  H-CEUS outperforms C-CEUS in diagnosing early renal damage in DN. H-CEUS perfusion parameters demonstrate temporal superiority over routine laboratory indices.

Utilization of the corticomedullary difference in magnetic resonance imaging-derived apparent diffusion coefficient for noninvasive assessment of chronic kidney disease in type 2 diabetes.

BACKGROUNDS: Accumulating data demonstrated that the cortico-medullary difference in apparent diffusion coefficient (ΔADC) of diffusion-weighted magnetic resonance imaging (DWI) was a better correlation with kidney fibrosis, tubular atrophy progression, and a predictor of kidney function evolution in chronic kidney disease (CKD). OBJECTIVES: We aimed to assess the value of ΔADC in evaluating disease severity, differential diagnosis, and the prognostic risk stratification for patients with type 2 diabetes (T2D) and CKD. METHODS: Total 119 patients with T2D and CKD who underwent renal MRI were prospectively enrolled. Of them, 89 patients had performed kidney biopsy for pathological examination, including 38 patients with biopsy-proven diabetic kidney disease (DKD) and 51 patients with biopsy-proven non-diabetic kidney disease (NDKD) and Mix (DKD + NDKD). Clinicopathological characteristics were compared according to different ΔADC levels. Moreover, univariate and multivariate-linear regression analyses were performed to explore whether ΔADC was independently associated with estimated glomerular filtration rate (eGFR) and urinary albumin creatinine ratio (UACR). The diagnostic performance of ΔADC for discriminating DKD from NDKD + Mix was evaluated by receiver operating characteristic (ROC) analysis. In addition, an individual's 2- or 5-year risk probability of progressing to end-stage kidney disease (ESKD) was calculated by the kidney failure risk equation (KFRE). The effect of ΔADC on prognostic risk stratification was assessed. Additionally, net reclassification improvement (NRI) was used to evaluate the model performance. RESULTS: All enrolled patients had a median ΔADC level of 86 (IQR 28, 155) × 10-6 mm2/s. ΔADC significantly decreased across the increasing staging of CKD (P < 0.001). Moreover, those with pathological-confirmed DKD has a significantly lower level of ΔADC than those with NDKD and Mix (P < 0.001). It showed that ΔADC was independently associated with eGFR (ß = 1.058, 95% CI = [1.002,1.118], P = 0.042) and UACR (ß = -3.862, 95% CI = [-7.360, -0.365], P = 0.031) at multivariate linear regression analyses. Besides, ΔADC achieved an AUC of 0.707 (71% sensitivity and 75% specificity) and AUC of 0.823 (94% sensitivity and 67% specificity) for discriminating DKD from NDKD + Mix and higher ESKD risk categories (≥50% at 5 years; ≥10% at 2 years) from lower risk categories (<50% at 5 years; <10% at 2 years). Accordingly, the optimal cutoff value of ΔADC for higher ESKD risk categories was 66 × 10-6 mm2/s, and the group with the low-cutoff level of ΔADC group was associated with 1.232 -fold (95% CI 1.086, 1.398) likelihood of higher ESKD risk categories as compared to the high-cutoff level of ΔADC group in the fully-adjusted model. Reclassification analyses confirmed that the final adjusted model improved NRI. CONCLUSIONS: ΔADC was strongly associated with eGFR and UACR in patients with T2D and CKD. More importantly, baseline ΔADC was predictive of higher ESKD risk, independently of significant clinical confounding. Specifically, ΔADC <78 × 10-6 mm2/s and <66 × 10-6 mm2/s would help to identify T2D patients with the diagnosis of DKD and higher ESKD risk categories, respectively.

Value of Contrast-enhanced Ultrasound Parameters in Evaluating K-W Nodule Formation in Diabetic Nephropathy / 中国医学科学院学报

Objective To discuss the value of contrast-enhanced ultrasound(CEUS)parameters in evaluating the formation of Kimmelstiel-Wilson(K-W)nodules in diabetic nephropathy(DN).Methods Sixty-two patients pathologically diagnosed with DN and undergoing CEUS in the First Medical Center of Chinese PLA General Hospital from March 2017 to January 2020 were assigned into two groups according to whether K-W nodules were formed.The cortical CEUS parameters and the ratios of cortical to medullary CEUS parameters were compared between the two groups.Results The 62 patients included 19 patients without K-W nodules(group A)and 43 patients with K-W nodules(group B).The median rise time(

Neuropad for detecting preclinical diabetic peripheral neuropathy

The case for adopting Neuropad to detect preclinical diabetic peripheral neuropathy is not supported by the evidence. Neuropad detects sub-normal sweating in patients with diabetes but the clinical importance of this in current NHS care pathways is poorly defined. There is insufficient evidence to support the use of Neuropad in patients in whom 10 g monofilament testing for diabetic peripheral neuropathy is not possible.