In vivo assessment of hypertensive nephrosclerosis using ultrasound localization microscopy

Abstract

As a typical chronic kidney disease (CKD), hypertensive nephrosclerosis (HN) is a common syndrome of hypertension, characterized by chronic kidney microvascular damage. Early diagnosis of microvascular damage using conventional ultrasound imaging encounters challenges in sensitivity and specificity owing to the inherent diffraction limit. Ultrasound localization microscopy (ULM) has been developed to obtain microvasculature and microvascular hemodynamics within the kidney, and would be a promising tool for the early diagnosis of CKD. Methods: In this study, the advantage of quantitative indexes obtained by using ULM (mean arterial blood flow speeds of different segments of interlobular arteries) over indexes obtained using conventional clinical serum (β2microglobulin,serum urea nitrogen,and creatinine) and urine ( 24-h urine volume and urine protein) tests and ultrasound Doppler imaging (peak systolic velocity [PSV], end-diastolic velocity [EDV], and resistance index [RI]) and contrastenhanced ultrasound imaging (CEUS; rise time [RT], peak intensity [IMAX], mean transit time [mTT], and area under the time-intensity curve [AUC]) for early diagnosis of HN were investigated. Examinations were carried out on six spontaneously hypertensive rats (SHR) and five normal Wistar-Kyoto (WKY) rats at the age of 10 weeks. Results:The experimental results show that the indicators derived from conventional clinical inspections (serum and urine tests) and ultrasound imaging (PSV, EDV, RI, RT, IMAX, mTT, and AUC) do not show significant difference between hypertensive and healthy rats (p > 0.05), while the TTP of the SHR group (28.52 ± 5.52 s) derived from CEUS is significantly higher than that of the WKY group (18.68 ± 7.32 s; p < 0.05). The mean blood flow speed in interlobular artery of SHR (12.47 ± 1.06 mm/s) derived from ULM is significantly higher than that of WKY rats (10.13 ± 1.17 mm/s; p < 0.01). Conclusion:The advantages of ULM over conventional clinical inspections and ultrasound imaging methods for early diagnosis of HN were validated. The quantitative results show that ULM can effectively diagnose HN at the early stage by detecting the blood flow speed changes of interlobular arteries. ULM may promise a reliable technique for early diagnosis of HN in the future.

Ultrasound super-resolution imaging for the differential diagnosis of thyroid nodules: A pilot study

“…Our results demonstrated no significant difference was showed in blood flow patterns between benign and malignant thyroid nodules as showed in Figure 3 . This diagnostic variability may be since CDFI cannot overcome the diffraction limit of ultrasound to truly reveal intra-nodular microvascular information ( 14 ).…”

“…In the last several decades, the application of contrast-enhanced ultrasound (CEUS) on thyroid-related diseases has greatly improved. CEUS can significantly enhance the US contrast echo of the bloodstream, nevertheless, the imaging resolution of CEUS is still limited by the diffraction limit of US applied ( 14 ). Therefore, CEUS is still insufficient to observe the microvasculature at the capillary level and also the microvascular flow rate (MFR) within the micro-vessels.…”

Super-Resolution Ultrasound Imaging Provides Quantification of the Renal Cortical and Medullary Vasculature in Obese Zucker Rats: A Pilot Study

“…Super-resolution (SR) ultrasound imaging has the potential to visualize the microvasculature in vivo, but the literature on pathological changes in the renal vasculature is limited [ 9 , 10 , 11 ]. One approach for SR imaging is based on localizing gas-filled intravascular microbubbles (MBs) [ 12 ].…”

Microvascular Imaging with Super-Resolution Ultrasound

“…For example, unlike sham-operated mice, mice with unilateral ischemia-reperfusion-induced chronic kidney disease had decreased vascular density and increased tortuosity in the renal cortex [19]. In another study, a vasodilator-induced decrease in microbubble velocity was found in the cortex and the deeper-lying medulla of rat kidneys [20], and lastly, increased microbubble velocity was found in the cortical radial arteries of hypertensive rats [21]. The cortical vessels of a human kidney have also been visualized with SRUS [22].…”

“…In einer anderen Studie wurde eine durch Vasodilatatoren induzierte Abnahme der Geschwindigkeit von Mikrobläschen im Cortex und im tiefer liegenden Mark von Rattennieren festgestellt [20]. Schließlich wurde eine erhöhte Geschwindigkeit von Mikrobläschen in der kortikalen A. radialis hypertensiver Ratten gefunden [21]. Die kortikalen Gefäße einer menschlichen Niere wurden ebenfalls mit SRUS visualisiert [22].…”