Published online Aug 28, 2018. doi: 10.4329/wjr.v10.i8.83
Peer-review started: May 4, 2018
First decision: June 6, 2018
Revised: June 26, 2018
Accepted: July 10, 2018
Article in press: July 10, 2018
Published online: August 28, 2018
Processing time: 117 Days and 20.2 Hours
Diabetic nephropathy (DN) remains one of the most common causes of morbidity and mortality in patients with type 2 diabetes worldwide. Early diagnosis of DN facilitates timely treatment, and therefore, improving patient outcomes. Although microalbuminuria (MAU) level is currently the primary standard for the diagnosis of DN, it may lag behind DN progression and has limited sensitivity.
Diffusion tensor imaging (DTI) quantifies the directional nature of water diffusion and is especially suited for specifically oriented organs such as the kidney. DTI parameter changes were reported in several renal pathologic conditions presenting itself as a potential biomarker of renal damage.
The main objective of this study was to explore the possibility of using renal DTI to detect early renal damage in patients with type 2 diabetes.
This prospective study included 26 diabetic patients (12 with MAU, and 14 with normoalbuminuria) and 14 healthy volunteers. Renal DTI on 3.0 T MR was performed and estimated glomerular filtration rate (eGFR) was recorded for each subject. Mean cortical and medullary fractional anisotropy (FA) values were separately calculated by placing multiple representative regions of interest. Mean FA values were statistically compared among groups, and correlations between FA values and eGFR were evaluated. The high-field MR offered high signal-to-noise ratio and the multiple sampling of renal parenchyma ensured the representativeness of the underlying pathological changes.
The results showed that both cortical and medullary FA were significantly reduced in diabetic patients compared to healthy controls. Cortical FA was significant lower in diabetic patients with NAU than healthy controls, indicating that the renal damage reflected by the FA changes occurred even earlier than the clinical detection of MAU. Both cortical FA and medullary FA correlated with eGFR, indicating that both renal cortex and medulla could be involved in the pathogenesis of DN.
In conclusion, both cortical and medullary FA could potentially exhibit early renal damage in type 2 diabetic patients, and therefore help to differentiate diabetic kidneys from healthy controls even before the clinical detection of MAU.
Based on these findings, renal DTI could be developed as an early biomarker in addition to the current examinations in the clinical practice. Further experimental or clinical studies with pathological results can be designed to reveal the specific underlying mechanism of FA reduction in DN.