OBJECTIVE:Ultrasound is central to lymph node assessment and guides targeted biopsy. However, conventional Doppler has limited sensitivity to slow microvascular flow. Super-resolution ultrasound imaging using erythrocytes (SURE) is a fast, contrast-free technique that previously demonstrated feasibility in normal axillary and inguinal lymph nodes, but not in malignant lymph nodes or in the anatomically challenging cervical region. This feasibility study evaluated whether SURE could visualize the microvascular architecture in malignant cervical lymph nodes in patients with head and neck cancer or lymphoma, with an exploratory qualitative and quantitative comparison with normal cervical lymph nodes. METHODS:This preliminary feasibility study included five malignant cervical lymph nodes and five sonographically normal cervical lymph nodes. Conventional B-mode and Doppler images were obtained for qualitative comparison, followed by SURE acquisitions reconstructed into intensity and velocity maps. Exploratory quantitative parameters included vascular density, vessel diameter and peak flow velocity. RESULTS:SURE depicted the microvasculature in malignant cervical lymph nodes in greater detail than Doppler. Normal lymph nodes showed organized hilar branching patterns, whereas malignant lymph nodes showed heterogeneous and disorganized vascular patterns with focal avascular regions. In this small exploratory cohort, vascular density appeared lower in malignant than in normal lymph nodes (p = 0.009), while no statistically significant differences were observed in vessel diameter or peak flow velocity. CONCLUSION:SURE was feasible for fast, contrast-free microvascular imaging of malignant cervical lymph nodes. The findings are exploratory, and further methodological optimization and larger validation studies, including clinically indeterminate lymph nodes, are required to establish clinical utility.

Tumour vascularity is an important biomarker of tumour growth and therapeutic response. Current in vivo imaging methods have a limited ability to detect individual tumour vessels due to the small vessel size and low flow rates commonly observed in murine oncology models. This paper presents three pilot studies which together aim to assess the performance of a developing imaging method, Super-resolution Ultrasound using Erythrocytes (SURE), for subcutaneous tumour imaging. Across three experiments, we qualitatively compared the vascular imaging sensitivity and clinical applicability of SURE imaging with colour Doppler imaging and ex vivo immunohistochemistry. Two murine oncology models were investigated: the LNCaP (lymph node carcinoma of the prostate) xenograft model (n = 3) and the B16-F10 melanoma model (n = 7). Optimal SURE post-processing parameters for subcutaneous tumour imaging were characterised. SURE demonstrated enhanced visualisation of tumour microvasculature relative to conventional colour Doppler imaging. SURE successfully visualised tumour microvasculature, detecting vessels approximately 30 μm in diameter while enabling haemodynamic characterisation. Optimal post-processing involved a trade-off between vascular imaging sensitivity, final signal-to-noise ratio, and image artefact prevalence. Vascular density measurements obtained using SURE did not differ significantly from those obtained by immunohistochemistry. SURE represents a significant advance in in vivo microvascular imaging. While post-processing time, image artefacts, and limited quantitative analysis currently limit preclinical application, the technique demonstrates strong potential for tumour vascular characterisation in both preclinical research and clinical oncology.

Background: Conventional Doppler ultrasound is limited by its angle dependence and its inability to characterize complex flow patterns adequately. Vector flow imaging (VFI) is an angle-independent ultrasound technique that enables two-dimensional velocity vector mapping and the assessment of hemodynamic parameters. This scoping review aims to map the current evidence on the application and validation of VFI for assessing carotid artery stenosis (CAS). Methods: Using the Population–Concept–Context framework, we included studies that evaluated the application, validity, or outcomes of vector flow imaging in individuals with suspected or confirmed carotid artery stenosis, as well as in healthy controls used for comparison or validation, in clinical or research settings. Five electronic databases were searched from inception through 30 April 2026. Studies limited to conventional Doppler ultrasound or to animal or phantom models without human validation were excluded. Data were synthesized using descriptive numerical analysis and narrative thematic synthesis. Results: A total of 48 sources of evidence met the inclusion criteria. Six trial registrations without reported results were excluded from synthesis, leaving 42 synthesized sources, including 40 original studies and two reviews. The most frequently reported parameters were wall shear stress (n = 25), turbulence indices (n = 11), and velocity vectors (n = 14). Most studies were cross-sectional (n = 20) or technical validation studies (n = 13) with small sample sizes (median 31 participants, IQR 10.5–57; range 1–476). The dominant research focus was plaque vulnerability assessment, while fewer studies addressed stenosis grading. Only eight studies reported diagnostic-performance metrics; none employed prespecified thresholds, two reported blinding, and none adhered to the Standards for Reporting Diagnostic Accuracy Studies guidelines (STARD). Conclusions: VFI enables detailed characterization of carotid hemodynamics, but the available evidence remains preliminary and does not establish clinical utility. Standardized, adequately powered studies with external validation are required before clinical implementation.

Medical ultrasound probes commonly employ a polymer encapsulation over the transducer for electrical protection and acoustic impedance matching. However, the speed of sound mismatch between the encapsulant and biological tissue can introduce time of flight (TOF) errors that degrade beamforming coherence. This article presents a beamforming method that includes the encapsulating layer in the TOF calculation to improve image quality. Two TOF approximations, direct path (DP) and normal path (NP), are evaluated in terms of accuracy and computational cost. These are compared against the homogeneous direct path (HDP) model, which neglects the encapsulant, and the exact Snell's law path (SP), computed using ray-tracing. Simulations and experiments are performed on a silicone encapsulated row-column addressed (RCA) capacitive micromachined ultrasound transducer (CMUT) probe as a case study. DP and NP increased the processing time by only 1.2 & times; compared to HDP, while SP increased it by 46 & times;. The measured standard deviation of the TOF error was reduced from 0.10 lambda (HDP) to 0.06 lambda (DP) and 0.05 lambda (SP), ensuring high interchannel coherence. Lateral resolution increased up to +47%, and contrast was enhanced by >= + 2.1 dB using DP and SP models compared to HDP. The DP approximation achieved near-SP image quality, while maintaining HDP-level computational efficiency. The validity domain of NP and DP for any transducer was generalized using a critical F-number alpha. Overall, the proposed approximations provide a computationally efficient means to enhance resolution and contrast, establishing a practical solution for high-resolution real-time imaging.

Wall shear stress (WSS) plays a crucial role in the initiation and progression of atherosclerosis. However, its noninvasive quantification remains challenging due to the limited spatiotemporal resolution and scalability of MRI, as well as the limited precision (±30% error range) and image quality trade-off of existing ultrasound-based approaches. This study presents an ultrasound-based wall shear stress imaging (WASHI) framework that simultaneously provides high-quality B-mode images and spatiotemporally resolved WSS maps, and evaluates its accuracy and precision. WASHI derives WSS directly from velocity gradients obtained using transverse oscillation vector flow imaging based on an interleaved synthetic aperture imaging sequence implemented on a Verasonics Vantage 256. Accuracy was assessed using a flow-rig setup under controlled conditions, and in vivo precision was evaluated in ten healthy volunteers through bilateral scans of the common carotid arteries (19 CCAs in total). In the flow-rig experiments,WASHI produced consistent WSS estimates across 0° and 20° tilting angles with accuracy comparable to a velocity-based estimator (bias: -1 mPa vs. -3 mPa). In in vivo measurements, WASHI successfully tracked vessel wall motion over multiple cardiac cycles and resolved both spatial and temporal variations in WSS along both vessel walls. The median coefficient of variation (CV) across the 19 CCAs was 10.2%, demonstrating high measurement precision. Although this precision was slightly lower than that of the velocity-based estimator (CV: 6.2%), WASHI produced WSS magnitudes (2.7 & 2.3 Pa) that closely reflected the captured flow profile (2.9 & 2.4 Pa). In addition, the intrasubject variability of time-averaged WSS was the same across participants (p = 0.45), indicating reproducible performance. These results demonstrate the feasibility of WASHI for precise and reproducible WSS imaging, enabling future longitudinal studies and large-cohort investigations of vascular hemodynamics.

Background/Objectives: Distinguishing melanoma from benign melanocytic nevi remains a central diagnostic challenge, and vascular features may provide additional information beyond surface morphology. Super-resolution ultrasound using the erythrocytes (SURE) is a contrast-free imaging technique that uses endogenous erythrocyte scattering signals to reconstruct microvascular architecture beyond the conventional diffraction limit. This study evaluated the feasibility of SURE for in vivo visualization and quantitative assessment of dermal microvasculature in clinically benign nevi. Methods: Eleven participants with 35 clinically benign dermal nevi were included. All lesions underwent clinical and dermoscopic assessment, conventional B-mode ultrasound, color and power Doppler imaging, and SURE imaging. Eight larger nevi were imaged in two imaging planes, resulting in 43 SURE acquisitions. SURE reconstructions were assessed qualitatively for microvascular morphology and quantitatively for vessel diameter and erythrocyte flow velocity in proximal, intermediate, and distal visible intralesional vessel segments. Results: Dermoscopic and conventional ultrasound images were acquired for all lesions. SURE reconstructions of sufficient quality for quantitative analysis were obtained for all included acquisitions, yielding 129 vessel diameter measurements and 129 corresponding velocity measurements. Conventional Doppler demonstrated absent or minimal detectable vascular signal in the majority of lesions, whereas SURE visualized branching structures consistent with dermal microvascular networks in all the lesions. The mean vessel diameter was 85.0 ± 20.2 µm, with measured diameters ranging from 48.1 to 173.0 µm. The median flow velocity was 1.80 [1.30–2.50] mm/s. No significant differences in vessel diameter or velocity were observed between proximal, intermediate, and distal intralesional segments. Conclusions: SURE enabled contrast-free in vivo visualization and quantitative assessment of low-velocity dermal microvasculature in clinically benign nevi. These findings support the feasibility of SURE for microvascular mapping of melanocytic lesions and provide a basis for future studies including malignant lesions, volumetric imaging, and histopathological validation.

Objectives: To systematically map the existing literature on ultrasound-based techniques for non-invasive visualization of the dermal microvasculature and identify methodological strengths, limitations, and evidence gaps. Methods: This scoping review was conducted according to PRISMA-ScR guidelines and registered on the Open Science Framework (DOI: 10.17605/OSF.IO/7VDUK). MEDLINE, PubMed, Embase, Scopus, and Web of Science were searched (January 2000-October 2025). Studies involving human participants and ultrasound-based techniques explicitly aimed at visualizing dermal microvasculature were included. Data on study design, population characteristics, imaging parameters, and reported outcomes were extracted and synthesized narratively. Results: Thirty-six studies published between 2007 and 2025 were included. Most were small feasibility or experimental studies (n = 24), with a median sample size of three participants and substantial heterogeneity in imaging protocols. Photoacoustic-based techniques were most frequently reported (n = 21) and were the most consistently described as providing high microvascular detail and functional assessment capability. High-frequency ultrasound (n = 10) and advanced Doppler methods (n = 7) also enabled visualization of dermal vessels, but showed variability in sensitivity, reporting, and standardization. Validation against histopathology was reported in only one study. Conclusions: Ultrasound-based techniques can visualize dermal microvasculature in vivo; however, evidence remains fragmented, methodologically heterogeneous, and largely derived from small exploratory studies. Standardized imaging protocols, pathology-based clinical cohorts and robust validation studies are required to establish comparative performance and enable clinical translation in radiology.

Super-resolution ultrasound imaging using the erythrocytes (SURE) visualizes microvasculature in seconds without contrast agents. However, it is computationally intensive because it uses processing steps similar to those in ultrasound localization microscopy (ULM). The hypothesis is that a graphics processing unit (GPU) can process SURE in real time, allowing the resulting images to be displayed immediately at the patient's bedside. The processing included beamforming, motion correction, tissue signal removal through singular value decomposition (SVD)-based filtering, and peak detection. All calculations were performed on the GPU, where batches of 32 frames were processed in parallel to improve hardware utilization. The image quality was compared with that of the original SURE implementation for in vivo rat kidney data acquired at 417 frames/s, and the processing rate was measured on an NVIDIA GeForce RTX 4090 GPU. The processing rate was 517 images/s, demonstrating real-time SURE imaging with GPU acceleration. Furthermore, the image quality was improved, with more blood vessels being clearly visualized. In conclusion, SURE imaging can be performed in real time, similar to power Doppler, enabling noninvasive super-resolution ultrasound imaging at the bedside.

Row-column (RC) arrays typically suffer from a limited field of view (FOV), with the imaging area confined to a rectangular region equal to the footprint of the probe. This limitation can be solved by using a diverging lens in front of the probe. Previous studies have introduced a Thin Lens model for beamforming lensed RC arrays, but this model inaccurately assumes the lens to be infinitely thin, leading to degraded resolution and contrast due to errors in the time of flight (TOF) calculations. This paper presents a beamformer based on ray tracing for accurate TOF calculation. A Verasonics Vantage 256 scanner was equipped with a Vermon RC probe with 128 + 128 elements, λ pitch, and a 6 MHz center frequency. A synthetic aperture ultrasound sequence with 96 virtual sources and 32 active elements for each emission with row elements was employed, and all column elements were used for acquiring data. This method was tested with a polystyrene (PS) lens with a spherical shape and polymethyl methacrylate (PMMA) in a Bicylindrical shape. Based on pressure field measurements, these two lenses provide a 20° and 33° FOV, respectively. The Thin Lens model had a lateral resolution of around 17.4λ for the Bicylindrical lens, whereas the new method achieves a resolution of around 3.8λ, representing a 4.6-fold improvement. The contrast is enhanced from 23.1 to 29.8 dB for the Bicylindrical lens while preserving the FOV.

Background/Objectives: Diabetic kidney disease (DKD) is a significant concern for global healthcare, particularly in individuals with diabetes. The Zucker rat strain is a commonly used model of type 2 diabetes, despite awareness that this animal can develop hydronephrosis. In this study, we present novel imaging data evaluating the accuracy of this animal model in replicating the vascular aspects of human DKD while examining the impact of hydronephrosis on its validity as a disease model. Methods: This study reused data from a population of male Zucker Diabetic Fatty (ZDF; n = 22) rats and Zucker Lean (ZL) rats (n = 22) aged 12 to approximately 40 weeks. Vascular casting was performed to enable visualisation of the renal vasculature. Anatomical regional volumes and vascular density data were obtained from μCT scans using image thresholding and manual analysis. The effects of hydronephrosis were evaluated using renal functional parameters and histological examination. Results: A significantly lower cortical vascular density, as well as lower total renal vascular density, was seen in ZDF rats compared to ZL rats, independent of age. We identified that hydronephrosis affected 92% of ZDF rats and 69% of ZL rats. Hydronephrosis cavity size was significantly correlated with the degree of hyperglycaemia and rate of diuresis but had no other detected impact on renal function, vascularity, or tissue histological architecture. Conclusions: These findings support using the Zucker rat strain as a model for vascular changes in DKD. Despite identifying severe hydronephrosis in this population, it had minimal quantifiable impact on renal function or diabetes modelling.

Tendon overuse injuries are a common clinical problem and are characterized by neovessel ingrowth. Invasive techniques have illustrated the presence of microvessels in both healthy and injured tendons, but conventional ultrasound imaging methods, such as power Doppler and color Doppler imaging, have significant limitations in visualizing slow flow due to their limited observation time. These methods can only detect blood flow when the tendon is diseased beyond a certain threshold. It is hypothesized that a recently introduced fast contrast-free super-resolution ultrasound technique (SURE) can reliably reveal microvasculature in injured human patellar tendons in both longitudinal and transverse views, achieving a resolution below lambda/2. This reliability is defined as the consistent detection of vessels in multiple scans. The SURE technique employed an interleaved synthetic aperture ultrasound imaging scheme with 2x12 virtual sources. Human data acquisition was conducted using a Verasonics research scanner paired with a 10 MHz GE L8-18iD linear array hockey stick probe. For comparison, the same probe was used with a commercial scanner (GE Logiq E9). The resulting images of the patellar tendons showed more detailed microvessel structures compared to conventional Doppler, identifying vessels as small as 44 mu m using SURE. Analyzing four different positions along two vessels in six individual 4.8-second segments of a complete data set demonstrated that these microvascular structures can be consistently detected over time, with a maximum standard deviation in vessel width of 7.0 mu m.

Super-resolution ultrasound (SRUS) techniques, ultrasound localization microscopy (ULM) and super-resolution using erythrocytes (SURE), resolve vasculature beyond the diffraction limit, yet detection thresholds and filtering can bias width estimates. This study tests whether modest spatial smoothing, matched to the system's effective resolution (Gaussian sigma = 15 mu m), reduces bias relative to micro-CT. A Sprague-Dawley rat kidney was imaged with SURE and ULM and co-registered to ex vivo micro-CT (5.45 mu m voxels). Vessel widths were measured as the full width half maximum of SRUS line profiles and local thickness on micro-CT along identical lines, stratified by vessel type (interlobar, arcuate, and cortial radial vessels). Without smoothing, SRUS underestimated micro-CT across classes: interlobar mean normalized error was -89.9 +/- 8.9 % (SURE) and -80.6 +/- 12.4 % (ULM); arcuate -59.9 +/- 13.1 % (SURE) and -87.2 +/- 10.9 % (ULM); radial -39.3 +/- 34.3 % (SURE) and -91.1 +/- 5.3 % (ULM). With smoothing, errors moved toward zero: interlobar 9.7 +/- 35.7 % (SURE) and -1.0 +/- 25.7 % (ULM); arcuate -4.3 +/- 40.5 % (SURE) and 28.8 +/- 41.3 % (ULM); radial 23.4 +/- 31.7 %(SURE) and 14.6 +/- 23.8 % (ULM). Paired, line-wise normalized improvements were predominantly positive, e.g., interlobar gains of 60 +/- 22 % (SURE) and 59 +/- 22 %, with the largest class-wise gain up to 73 +/- 21 % for radial vessels in ULM. These results show that resolution-matched smoothing mitigates systematic underestimation in SRUS width estimates, yielding near-unbiased ULM interlobar measurements and attenuated bias across vessel classes, and support modality-aware preprocessing for structural quantification in SRUS.

This work introduces a complex-valued gradient optimization approach for precise motion estimation and correction in high-framerate ultrasound imaging. The method is hypothesized to outperform non-optimization approaches such as transverse oscillation, speckle tracking, and an intensity-based optimization approach. This is then hypothesized to result in quantifiable image quality improvements when used for motion correction during microvascular flow imaging with ultrasound. Motion estimation is achieved by iteratively aligning neighboring beamformed ultrasound frames to minimize the per-pixel magnitude of the complex-valued difference. In ultrasound microvascular simulations with a maximum global tissue motion of 6.6 mm/s and a maximum displacement of 1.7 mm, the mean motion error compared to prior phase-based techniques is reduced by a factor of 5.1 for lateral and 2.4 for axial motion. Comparing neighbor-frame complex gradient optimization-based motion estimation to transverse oscillation motion estimation, median lateral and axial motion error is, respectively, reduced to 0.9 and 0.17 mu m from an original 5.08 and 0.56 mu m, demonstrating sub-micrometer accuracy motion estimation with a 154 mu m transmit wavelength. Tested on in vivo ultrasound data of a Sprague-Dawley rat kidney, the peak residual tissue signal after echo cancellation is reduced by approximately 11 dB compared to prior techniques. In summary, motion estimation using complex gradient optimization has sub-micron accuracy in microvascular simulations and is shown to reduce residual tissue signal for in vivo ultrasound microvascular imaging.

Multi-element ultrasound arrays are not always perfect, especially when produced using experimental technology. Element variability leads to deterioration of image quality, which prevents a fair comparison to more established transducer manufacturing technologies. This paper presents an approach to compensate for the geometric (Z-axis) imperfections of a transducer, relying on the characterization results of its individual elements. It is hypothesized that compensating for the geometric imperfection of the transducer can significantly improve the ultrasound image quality. The potential of the approach is evaluated through image quality comparison using a commercial transducer, an experimental transducer, and a multi-wire phantom. For a wire at 75 mm depth, the lateral width of a wire image is reduced from 7.4 lambda to 3.1 lambda, and the cystic contrast (r = 2.5 lambda) is improved from -21.4 dB to -31.1 dB.

Row-Column Addressed (RCA) transducers are promising for achieving high-resolution volumetric imaging. However, their clinical applicability is constrained by an inherently limited Field of View (FOV), which is restricted to the physical aperture of the transducer. A cost-effective and flexible solution to increase the FOV is to use a diverging lens. Yet, the geometry of the lens might introduce inhomogeneities in the transmit pressure field. This work investigates the impact of various sources of inhomogeneities and provides a framework for lens design and performance assessment. Three lenses are fabricated, investigating different strategies to optimize the FOV. The Spherical lens provided the most homogeneous pressure field but the smallest effective FOV (17 degrees). The BiCylindrical lens provided a larger FOV (26 degrees), due to a smaller curvature, but the incomplete coverage translated into hotspots in the pressure field. The BiQuadratic lens yielded the largest FOV (36 degrees), due to its steep curvature, despite a rapid pressure drop at the edges of the transmit field. Ray-tracing simulations successfully captured the observed inhomogeneities, demonstrating their value for lens optimization. Finally, it was found that the effective FOV of lensed arrays, including those generating inhomogeneous pressure fields, is more robustly characterized using a 30 dB Signal to Noise Ratio (SNR) criterion rather than the conventional -6 dB isoline derived from the transmit pressure field. These findings provide a practical framework for optimizing acoustic lens design to achieve effective large-scale volumetric ultrasound imaging.

A rapid, contrast-free method for ultrasound superresolution vector flow imaging is introduced. The approach enhances the SURE-Hankel pipeline by integrating frequency-based directional separation, Hankel-matrix Singular Value Decomposition (HSVD), and localized optical flow estimation. A multi-stage process isolates overlapping erythrocyte signals based on their directional and spatiotemporal characteristics. Subsequently, optical flow is applied to the envelope of these separated modes for 2D flow vector estimation. The method's validation was performed on an in vivo rat kidney (8.7 MHz center frequency, wavelength lambda approximate to 178 mu m). For 1-second acquisitions, spatial resolution was improved to 40.8 mu m from 57.5 mu m using standard SURE. Flow direction accuracy, quantified against ULM velocimetry, resulted in a mean absolute Flow Angle Difference of 28.7 degrees and a mean bias of 1.3 degrees, successfully determining flow direction both axially and laterally. This technique enables accurate, non-invasive vector flow mapping of the microvasculature within acquisitions compatible with a single breath-hold.

Background: Vascular imaging is essential for clinical practice, research, and the diagnosis and management of vascular diseases. Super-resolution ultrasound (SRUS) imaging is an emerging high-resolution imaging technique with broad applications in soft tissue vascular imaging. However, the impact of biological and clinical variables on its imaging accuracy is currently unknown. This study investigates these factors in an animal model and compares SRUS with contrast-enhanced µCT. Methods: Kidney scans from 29 Zucker rats (Zucker Diabetic Fatty and Zucker Lean) were retrospectively analysed. The left kidney was imaged in vivo using SRUS during microbubble infusion, then filled with Microfil and excised for ex vivo µCT. SRUS parameters and clinical variables were analysed, and SRUS scans were co-registered with µCT to compare vascular density measurements. Results: Mean arterial blood pressure and anaesthesia time showed significant linear relationships with SRUS microbubble detection and vascular track reconstruction. The anaesthesia time was also strongly correlated with vascular density measurement. Visualisation and velocity estimations of renal arteries were limited with SRUS. Ultrasound signal attenuation had significant impacts, particularly in cortical far-field imaging. Despite differences between kidney regions, the vascular density distribution did not differ considerably between SRUS and µCT datasets for whole-kidney imaging. Conclusions: This study outlines key factors SRUS users must consider for optimal technique use. Careful region selection and control of clinical variables ensure more reliable and comparable images. Further research is necessary to translate these findings from a rat model into clinical application.

Ultrasound Localization Microscopy (ULM) can map microvasculature and microcirculation with unprecedented resolution by tracking isolated microbubbles (MB). The common MB tracking methods in ULM, such as the Hungarian algorithm or nearest-neighbor approaches, are fast and robust. However, while Kalman filter methods enable robust MB tracking and improve blood flow speed measurements, they often fail to reveal detailed and low-velocity microvasculature and microcirculations. This study hypothesizes that the fusion of MB trajectories from Hungarian and Kalman filter-based methods will enhance the visualization of the density and velocity images in ULM. ULM results for a rat kidney were compared across the tracking methods. The Hungarian tracker effectively captures dense vascular networks, while the Kalman tracker provides stable velocity estimates. Their combination leverages the strengths of both methods, revealing more continuous and detailed microvascular structures in both density and velocity maps compared to either tracker alone.

Lymph nodes play a crucial role in cancer metastasis, and assessing lymph node involvement is essential for patient prognosis and treatment strategies. Super-resolution ultrasound imaging (SRUS), including ultrasound localization microscopy (ULM), has shown promise in visualizing the lymph node microvasculature, however, ULM requires microbubbles injection, monitoring, and long acquisition times. This study investigates the feasibility of using a fast contrast-free SRUS approach based on erythrocytes (SURE) to visualize and quantify the microvasculature in human lymph nodes. The SURE pipeline detects and tracks erythrocyte scatterer peaks to generate high-resolution microvascular images with a resolution of less than half the wavelength in 2 seconds of data acquisition. SURE visualized the microvasculature, flow direction, and velocity in four normal human lymph nodes, detecting vessels as small as 40 μm in diameter and blood flow velocities ranging from 2 to 15 mm/s. The time evolution of SURE images from 0.1 to 10 seconds was demonstrated, and the SURE consistency was validated by processing SURE images of the same lymph node acquired at different time points. The SURE approach offers a fast contrast-free method for assessing human lymph node microvascular characteristics, providing a promising tool for lymph node evaluation in clinical settings.