Evaluation of Early Diabetic Kidney Disease Using Ultrasound Localization Microscopy: A Feasibility Study

Abstract

ObjectiveThe purpose of this study is to detect the hemodynamic changes of microvessels in the early stage of diabetic kidney disease (DKD) and to test the feasibility of ultrasound localization microscopy (ULM) in early diagnosis of DKD.MethodsIn this study, streptozotocin (STZ) induced DKD rat model was used. Normal rats served as the control group. Conventional ultrasound, contrast‐enhanced ultrasound (CEUS), and ULM data were collected and analyzed. The kidney cortex was divided into four segments, which are 0.25–0.5 mm (Segment 1), 0.5–0.75 mm (Segment 2), 0.75–1 mm (Segment 3), and 1–1.25 mm (Segment 4) away from the renal capsule, respectively. The mean blood flow velocities of arteries and veins in each segment were separately calculated, and also the velocity gradients and overall mean velocities of arteries and veins. Mann–Whitney U test was used for comparison of the data.ResultsQuantitative results of microvessel velocity obtained by ULM show that the arterial velocity of Segments 2, 3, and 4, and the overall mean arterial velocity of the four segments in the DKD group are significantly lower than those in the normal group. The venous velocity of Segment 3 and the overall mean venous velocity of the four segments in the DKD group are higher than those in the normal group. The arterial velocity gradient in the DKD group is lower than that in the normal group.ConclusionULM can visualize and quantify the blood flow and may be used for early diagnosis of DKD.

Value of Ultrasound Super-Resolution Imaging for the Assessment of Renal Microcirculation in Patients with Acute Kidney Injury: A Preliminary Study

“…US SRI, also called ultrasound localization microscopy (ULM) [ 17 ], can capture images and track the movement trajectory of microbubbles at an extremely high speed (500 frames/s) over a very short period (several seconds) [ 18 ], automatically generating microvascular images of living tissues. SRI technology can improve the resolution of blood vessels, with a spatial resolution of 100 μm, and the results of the present study showed that the tiny blood vessels near the renal capsule were clearly visible ( Figure 1 D,E).…”

Contrast Agent‐Free 3D Renal Ultrafast Doppler Imaging Reveals Vascular Dysfunction in Acute and Diabetic Kidney Diseases

“…[ 52 , 53 , 54 , 55 ] Disregarding the inapplicability of the aforementioned techniques, our study's findings align with several preceding CEUS, MRI, and super‐resolution USI studies with the same or similar AKI and DKD preclinical models. [ 32 , 56 , 57 , 58 ] Instead, we exploited eGFR, a clinically‐prevalent parameter, as a cross‐validative measure of kidney perfusion. The correlation between eGFR and nephropathy under AKI and DKD is well established in clinics.…”

“…Better resolution can be possibly achieved through super‐resolution localization techniques, although this may come at the cost of increased acquisition time and require the use of contrast agents. [ 56 , 62 ] With improved resolution, we might be able to directly observe glomerular and tubular pathogenesis. Moreover, the current linear scanning method results in anisotropic resolutions in the cross‐sectional and elevational directions.…”

Super-Resolution Ultrasound Imaging of Renal Vascular Alterations in Zucker Diabetic Fatty Rats during the Development of Diabetic Kidney Disease

“…Contrast-enhanced ultrasound (CEUS), used in clinics, is often unable to distinguish early kidney disease from the healthy kidney; instead, the MB pattern is used to differentiate solid renal tumors from pseudo-tumors [58]. Zhang et al showed no significant differences in renal perfusion using CEUS on a streptozotocininduced DKD rat model compared with healthy controls [23]. Other imaging modalities have shown to be limited in resolution as well.…”

“…Recently, SRUS showed a superiority to ultrasound in the evaluation of human kidney allograft vascularization [19]. Additionally, SRUS has been used on rodent kidneys to detect decreased vascular density after acute kidney injury and flow-velocity changes [20][21][22][23]. However, altered renal vascular morphology as a consequence of DKD development has not previously been investigated using SRUS.…”