Renal Pathology

Diagnosis of diabetic kidney disease in whole slide images via AI-driven quantification of pathological indicators

Diagnosis of diabetic kidney disease (DKD) mainly relies on screening the morphological variations and internal lesions of glomeruli from pathological kidney biopsy. The prominent pathological alterations of glomeruli for DKD include glomerular hypertrophy and nodular mesangial sclerosis. However, the qualitative judgment of these alterations is inaccurate and inconstant due to the intra- and inter-subject variability of pathologists. It is necessary to design artificial intelligence (AI) methods for accurate quantification of these pathological alterations and outcome prediction of DKD. In this work, we present an AI-driven framework to quantify the volume of glomeruli and degree of nodular mesangial sclerosis, respectively, based on an instance segmentation module and a novel weakly supervised Macro-Micro Aggregation (MMA) module. Subsequently, we construct classic machine learning models to predict the degree of DKD based on three selected pathological indicators via factor analysis. These corresponding modules are trained and tested on a total of 281 whole slide images (WSIs) digitized from two hospitals with different scanners. Our designed AI framework achieved inspiring results with 0.926 mIoU for glomerulus segmentation, and 0.899 F1 score for glomerulus classification in the external testing dataset. Meantime, the visualized results of the MMA module could reflect the location of the lesions. The performance of predicting disease achieved the F1 score of 0.917, which further proved the effectiveness of our AI-driven quantification of pathological indicators. Additionally, the interpretation of the machine learning model with the SHAP method showed similar accordance with the development of DKD in pathology. In conclusion, the proposed auxiliary diagnostic technologies have the feasibility for quantitative analysis of glomerular pathological tissues and alterations in DKD. Pathological quantitative indicators will also make it more convenient to provide doctors with assistance in clinical practice.

An efficient glomerular object locator for renal whole slide images using proposal-free network and dynamic scale evaluation method

In the diagnosis of chronic kidney disease, glomerulus as the blood filter provides important information for an accurate disease diagnosis. Thus automatic localization of the glomeruli is the necessary groundwork for future auxiliary kidney disease diagnosis, such as glomerular classification and area measurement. In this paper, we propose an efficient glomerular object locator in kidney whole slide image(WSI) based on proposal-free network and dynamic scale evaluation method. In the training phase, we construct an intensive proposal-free network which can learn efficiently the fine-grained features of the glomerulus. In the evaluation phase, a dynamic scale evaluation method is utilized to help the well-trained model find the most appropriate evaluation scale for each high-resolution WSI. We collect and digitalize 1204 renal biopsy microscope slides containing more than 41000 annotated glomeruli, which is the largest number of dataset to our best knowledge. We validate the each component of the proposed locator via the ablation study. Experimental results confirm that the proposed locator outperforms recently proposed approaches and pathologists by comparing F 1 and run time in localizing glomeruli from WSIs at a resolution of 0.25 μm/pixel and thus achieves state-of-the-art performance. Particularly, the proposed locator can be embedded into the renal intelligent auxiliary diagnosis system for renal clinical diagnosis by localizing glomeruli in high-resolution WSIs effectively.

Indications and results of renal biopsy in children: a 36-year experience

BACKGROUND

This study was conducted to investigate retrospectively the indications for renal biopsy (RB) in native kidneys and to analyze pathological findings in a single tertiary pediatric hospital in Southern Italy for the last 36 years.

METHODS

All patients who underwent RB at our hospital from 1979 to 2014 were included. All renal tissue specimens were studied under light and immunofluorescent microscopy, while electron microscopy was performed only for specific clinical indications.

RESULTS

The study group included 213 patients (female 43.2%) who underwent 225 percutaneous native kidney biopsies. Median age was 10.4 years (range 0.6-24 years). The most frequent indication for RB was nephrotic syndrome (44.4%), followed by proteinuria (27.6%), asymptomatic hematuria (17.3%) and acute kidney injury (9.8%). Gross hematuria appeared after biopsy in less than 5% of the patients, but none of them needed blood transfusion. Adequate renal tissue sample was obtained in 95.5% of the renal biopsies. Primary glomerulonephritis (GN) was the most common finding (61.4%), followed by secondary GN (21.4%), tubulointerstitial diseases (3.7%) and hereditary nephropathy (2.8%), while in 10.7% of the cases, normal renal tissues were found. According to histopathological diagnosis, the most common causes of primary GN were IgA nephropathy (20.9%), followed by minimal change disease (18.1%) and focal segmental glomerulosclerosis (11.6%).

CONCLUSIONS

The epidemiology of glomerular disease in our single-center cohort is similar to that shown in other national and international reports. Moreover, our study shows that percutaneous ultrasound-guided RB is a safe, reliable and effective technique in children.

Renal function and histology in children after small bowel transplantation

CKD is a frequent long-term complication after SBTx. CNIs are a well-known factor, but probably not the only cause. We assessed the incidence, risk factors, and severity of CKD in 27 children with SBTx (15 combined liver/SBTx) and prednisone/TAC-based maintenance immunosuppression. Median follow-up was seven yr (3-21). A renal biopsy was performed in 14 patients, 1-18 yr post-SBTx. A reduced GFR was observed in 17 children (63%) during the follow-up with none requiring dialysis. CNI toxicity was observed in 11/14 biopsies, as early as two yr post-transplant, and could occur with a normal mGFR. The dose of TAC was reduced by 50% in 13 patients with CKD and/or significant kidney histological lesions, and six were also given MMF. This led to a significant improvement in renal function: mGFR normalized in eight patients and improved or stabilized in five. No rejection occurred. At last follow-up, 37% had CKD stage 2 and 15% had CKD stage 3. In conclusion, CKD is frequent in children after SBTx and probably multifactorial. Less nephrotoxic immunosuppressive protocols may improve mGFR and should be further considered. The kidney histology helps in designing personalized immunosuppression strategies for patients.