Assessment of kidney function in chronic kidney disease by combining diffusion tensor imaging and total kidney volume

3.0 T diffusion tensor imaging and fiber tractography of the testes in nonobstructive azoospermia

PURPOSE

To assess the role of 3.0 T Diffusion Tensor Imaging (DTI) and Fiber Tractography (FT) of the testes in the work-up of nonobstructive azoospermia (NOA).

METHODS

This prospective study included consecutive NOA men and controls. A 3.0 T scrotal MRI was performed, including DTI. The testicular apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were calculated. FT reconstructions were created. The Kruskal-Wallis test, followed by pairwise comparisons, assessed differences in testicular ADC and FA between NOA histologic phenotypes (group 1: hypospermatogenesis; group 2: maturation arrest; and group 3: Sertoli cell-only syndrome) and normal testes. The Mann-Whitney-U test compared ADC and FA between NOA testes with positive and negative sperm retrieval. Visual assessment of the testicular fiber tracts was performed. Fiber tracts fewer in number, of reduced thickness, disrupted and/or disorganized were considered "abnormal". Chi-square tests and binary logistic regression analysis assessed variations in testicular fiber tracts morphology.

RESULTS

Twenty-nine NOA men (mean age: 39 ± 5.93 years) and 20 controls (mean age: 26 ± 5.83 years) were included for analysis. Higher ADC (p < 0.001) and FA (p < 0.001) was observed in NOA testes compared to controls. Differences in FA were found between groups 1 and 3 (0.07 vs 0.10, p = 0.26) and groups 2 and 3 (0.07 vs 0.10, p = 0.03), but not between groups 1 and 2 (p = 0.66). An increase in FA was observed in NOA testes with Sertoli cell-only syndrome compared to hypospermatogenesis and maturation arrest. FA was higher in NOA testes with negative results for the presence of sperm compared to those with positive results (0.09 vs 0.07, p = 0.006). FT showed "abnormal" fiber tracts in NOA testes (p < 0.001).

CONCLUSION

3.0 T DTI and FT provide an insight into deranged spermatogenesis in NOA testes.

Evaluation of renal function in chronic kidney disease (CKD) by mDIXON-Quant and Amide Proton Transfer weighted (APTw) imaging

BACKGROUND

Chronic kidney disease (CKD) is a long-term condition that affects >10% of the adult population worldwide. Noninvasive assessment of renal function has important clinical significance for disease diagnosis and prognosis evaluation.

OBJECTIVE

To explore the value of mDIXON-Quant combined with amide proton transfer weighted (APTw) imaging for accessing renal function in chronic kidney disease (CKD).

MATERIALS AND METHODS

Twenty-two healthy volunteers (HVs) and 30 CKD patients were included in this study, and the CKD patients were divided into the mild CKD (mCKD) group (14 cases) and moderate-to-severe CKD (msCKD) group (16 cases) according to glomerular filtration rate (eGFR). The cortex APT (cAPT), medulla APT (mAPT), cortex R2⁎ (cR2⁎), medulla R2⁎ (mR2⁎), cortex FF (cFF) and medulla FF (mFF) values of the right renal were independently measured by two radiologists. Intra-group correlation coefficient (ICC) test was used to test the inter-observer consistency. The analysis of variance (ANOVA) was used to compare the difference among three groups. Mann-Whitney U test was used to analyze the differences of R2⁎, FF and APT values among the patient and HV groups. Area under the receiver operating characteristic (ROC) curve (AUC) was used to analyze the diagnostic efficiency. The corresponding threshold, sensitivity, and specificity were obtained according to the maximum approximate index. The combined diagnostic efficacy of R2⁎, FF, and APT values was analyzed by binary Logistic regression, and the AUC of combined diagnosis was compared with the AUC of the single parameter by the Delong test.

RESULTS

The cAPT value of the HV, mCKD and msCKD groups increased gradually. The mAPT value and cR2⁎ values of the mCKD and msCKD groups were higher than those of the HV group, while the mFF value of the mCKD group was lower than HV group (all P < 0.05). The cAPT and mAPT values showed good diagnostic efficacy in evaluating different degrees of renal damage, while cR2⁎ and mFF values showed moderate diagnostic efficacy. When combining the APT, R2⁎, and FF values, the diagnostic efficiency was significantly improved.

CONCLUSION

mDIXON-Quant combined APTw imaging can be used for improved diagnosis of CKD.

Current progress in artificial intelligence-assisted medical image analysis for chronic kidney disease: A literature review

Chronic kidney disease (CKD) causes irreversible damage to kidney structure and function. Arising from various etiologies, risk factors for CKD include hypertension and diabetes. With a progressively increasing global prevalence, CKD is an important public health problem worldwide. Medical imaging has become an important diagnostic tool for CKD through the non-invasive identification of macroscopic renal structural abnormalities. Artificial intelligence (AI)-assisted medical imaging techniques aid clinicians in the analysis of characteristics that cannot be easily discriminated by the naked eye, providing valuable information for the identification and management of CKD. Recent studies have demonstrated the effectiveness of AI-assisted medical image analysis as a clinical support tool using radiomics- and deep learning-based AI algorithms for improving the early detection, pathological assessment, and prognostic evaluation of various forms of CKD, including autosomal dominant polycystic kidney disease. Herein, we provide an overview of the potential roles of AI-assisted medical image analysis for the diagnosis and management of CKD.

Effectiveness of functional magnetic resonance imaging for early identification of chronic kidney disease: A systematic review and network meta-analysis

PURPOSE

The commonly used clinical indicators are not sensitive enough on detecting early chronic kidney disease (CKD), whether functional magnetic resonance imaging (fMRI) can be regarded as a new noninvasive method to identify early stages of CKD and even different stages remains unknown. We performed a network meta-analysis to explore the question.

METHODS

Five databases were searched to identify eligible articles from 2000 to 2022. The outcome indicators were imaging biomarkers of fMRI techniques, including apparent diffusion coefficient (ADC) by diffusion-weighted imaging (DWI), fractional anisotropy (FA) by diffusion tensor imaging (DTI), diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f) by intravoxel incoherent motion imaging (IVIM), and apparent relaxation rate (R2*) by blood oxygen level-dependent (BOLD).

RESULTS

A total of 21 articles with 1472 patients were included for analysis. Cortical FA, f, and R2* values in CKD stages 1-2 were found statistically different with healthy controls (mean difference (MD), -0.03, 95% confidence interval (CI) -0.05, -0.01; MD, -0.04, 95% CI -0.06, -0.02; MD, 2.22, 95% CI 0.87, 3.57, respectively), and cortical ADC values were significantly different among different CKD stages (stages 3 and 1-2: MD, -0.15, 95% CI -0.23, -0.06; stages 4-5 and 3: MD -0.27, 95% CI -0.39, -0.14).

CONCLUSION

The results indicated fMRI techniques had great efficacy in assessing early stages and different stages of CKD, among which DTI, IVIM, and BOLD exerted great superiority in differentiating early CKD patients from the general population, while DWI showed the advantage in distinguishing different CKD stages.

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

PURPOSE

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.

MATERIALS AND METHODS

Twenty-two (female:male, 14:8; age, 48 ± 10 years) 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.

RESULTS

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.

CONCLUSION

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.

Clinical study on the use of advanced magnetic resonance imaging in lupus nephritis

OBJECTIVES

To investigate the correlation between the histopathology of the kidney and clinical indicators in patients with lupus nephritis (LN) using magnetic resonance imaging (MRI).

METHODS

A total 50 female participants were enrolled in the study. Thirty patients with LN were divided into types 2, 3, 4, and 5, according to their pathological features. The control group consisted of 20 healthy female volunteers. Serum creatinine, C3, C1q, and anti-ds-DNA were measured. Conventional MRI, DTI, DWI, and BOLD scanning was performed to obtain the FA, ADC, and R2* values for the kidney.

RESULTS

Compared with the control group, FA and the ADC were decreased in patients with LN, while the R2* value was increased (P < 0.05). The overall comparison of the SLEDAI (Activity index of systemic lupus erythematosus) score, total pathological score, AI, and serum creatinine C3 showed that these were significantly different between the two groups (P < 0.05). FA and the ADC were negatively correlated with urinary, blood ds-DNA, and serum creatinine and positively correlated with C1q (P < 0.05). The R2* value was positively correlated with urinary NGAL, blood ds-DNA, and serum creatinine (P < 0.05). FA and the ADC were negatively correlated with the SLEDAI score, total pathological score, AI, CI, nephridial tissue C3, and C1q. The R2* value was positively correlated with the SLEDAI score, total pathological score, AI, CI, nephridial tissue C3, and C1q (P < 0.05).

CONCLUSIONS

MRI examination in female patients with LN was correlated with pathologic test results, which may have clinical significance in determining the disease's severity, treatment, and outcome.

Relationship between Acute Respiratory Tract Infection and the Serum 25(OH) D3 Level in Chronic Kidney Disease Patients and Its Prevention and Treatment

Observational studies and randomized controlled studies propose that vitamin D plays a significant role in preventing acute respiratory tract infection (RTI); however, results are inconsistent and the optimal serum 25-hydroxyvitamin D (25-OH-D3) concentration remains unknown. This study explores the risk factors associated with acute RTI in patients with chronic kidney disease (CKD) and analyzes its correlation with serum 25-OH-D3 levels, to provide appropriate preventive treatment measures for CKD patients complicated with acute RTI. Seventy cases of CKD patients treated in the department of nephrology of Jiangxi Provincial People’s Hospital are recruited as the research objects and divided into a control group (CKD without RTI) and an observation group (CKD with RTI), with 35 cases in each group. The laboratory indexes and serum 25-OH-D3 levels are compared between the two groups. The area under the receiver operating characteristic curve (ROC) of 25-OH-D3 in the diagnosis of CKD patients complicated with RTI is 0.892, and the standard error is 0.038. The glomerular filtration rates (GFR) are $48.32\pm 9.87\text{mL}/\min$ and $50.18\pm 20.71\text{mL}/\min$ in the control group and the experimental group, respectively, with no statistical significance between the two groups ( $P>0.05$ ). The serum 25-OH-D3 content in the control group ( $35.08\pm 6.2\text{nmol}/\text{L}$ ) is dramatically higher than that in the observation group ( $20.71\pm 5.87\text{nmol}/\text{L}$ ) ( $P<0.05$ ). The proportion of patients with diabetes mellitus (DM) in the control group and observation group is 25.71% and 68.57%, respectively, with a considerable difference ( $P<0.05$ ). In the control group and the experimental group, the proportion of patients with oral vitamin D receptor agonists is 54.29% and 11.43%, respectively, and the difference is significant ( $P<0.05$ ). Results show that the serum 25-OH-D3 level is highly correlated with the occurrence of RTI in CKD patients. In addition, it is related to patients’ age, DM, and vitamin D receptor agonists.

Multiparametric quantitative renal MRI in children and young adults: comparison between healthy individuals and patients with chronic kidney disease

PURPOSE

Multiparametric quantitative renal MRI may provide noninvasive radiologic biomarkers of chronic kidney disease (CKD) based on investigations in animal models and adults. We aimed to (1) obtain normative multiparametric quantitative MRI data from the kidneys of healthy children and young adults, (2) compare MRI measurements between healthy control participants and patients with CKD, and (3) determine if MRI measurements correlate with clinical and laboratory data as well as histology.

METHODS

This was a prospective, case-control study of 20 healthy controls and 12 CKD patients who underwent percutaneous renal biopsy ranging from 12 to 23 years of age between October 2018 and March 2020. Kidney function was documented and pathology assessed for fibrosis/inflammation. Utilizing a field strength of 1.5T, we examined renal T1, T2, and T2* relaxation mapping, MR elastography (MRE), and diffusion-weighted imaging (DWI). A single analyst made all manual measurements for quantitative MRI pulse sequences. Independent measurements from cortex, medulla, and whole kidney were obtained by drawing regions of interest on single slices from the upper, mid, and lower kidney. A weighted average was calculated for each kidney; if two kidneys, the right and left were averaged. Continuous variables were compared with Mann-Whitney U test; bivariate relationships were assessed using Spearman rank-order correlation.

RESULTS

Median estimated glomerular filtration rate (eGFR) was 112.3 ml/min/1.73 m² in controls (n = 20, 10 females) and 55.0 ml/min/m² in CKD patients (n = 12, 2 females) (p < 0.0001). Whole kidney (1333 vs. 1291 ms; p = 0.018) and cortical (1212 vs 1137 ms; p < 0.0001) T1 values were higher in CKD patients. Cortical T1 values correlated with eGFR (rho = - 0.62; p = 0.0003) and cystatin C (rho = 0.58; p = 0.0007). Whole kidney (1.87 vs. 2.02 10^-3 mm²/s; p = 0.007), cortical (1.89 vs. 2.04 10^-3 mm²/s; p = 0.008), and medullary (1.87 vs. 1.98 10^-3 mm²/s; p = 0.0095) DWI apparent diffusion coefficients (ADC) were lower in CKD patients. Whole kidney ADC correlated with eGFR (rho = 0.45; p = 0.012) and cystatin C (rho = - 0.46; p = 0.009). Cortical histologic inflammation correlated with DWI ADC (rho = - 0.71; p = 0.011).

CONCLUSION

Renal T1 relaxation and DWI ADC measurements differ between pediatric healthy controls and CKD patients, correlate with laboratory markers of CKD, and may have histologic correlates.

Does Chronic Kidney Disease Affect the Surgical Outcome and Prognosis of Patients with Gastric Cancer? A Meta-Analysis

The purpose of this meta-analysis was to evaluate the impact of chronic kidney disease on short-term complications and long-term survival in patients with gastric cancer.

The PubMed, Embase, and Cochrane Library databases were searched from inception to May 18, 2021. The search strategy focused on two keywords: chronic kidney disease and gastric cancer. Pooled odds ratios, mean differences, and hazard ratios were analyzed. RevMan 5.3 was used for data analysis in this meta-analysis.

A total of seven studies including 3,346 patients were included in this meta-analysis. The chronic kidney disease group had a higher proportion of males and older patients, lower albumin levels, higher comorbidity rates, and higher N staging. The chronic kidney disease group had higher rates of overall postoperative complications (OR = 2.05, 95% CI = 1.38 to 3.05, P = 0.0004), more severe postoperative complications (OR = 2.06, 95% CI = 1.59 to 2.66, P < 0.00001), and higher rates of cardiovascular-related complications, anastomotic leakage, pneumonia, wound infections, pancreatic-related diseases and short-term death. Furthermore, the chronic kidney disease group had poorer overall survival than the nonchronic kidney disease group (HR = 2.89, 95% CI = 2.20 to 3.80, P < 0.00001).

Preexisting chronic kidney disease was associated with higher complications and poorer overall survival following gastrectomy in patients with gastric cancer.