Validation of Vessel Width in Super-Resolution Ultrasound Imaging Using Micro-CT

Description

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 σ = 15 µm), 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 µm 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.

Period	16 Sept 2025
Event title	2025 IEEE International Ultrasonics Symposium
Event type	Conference
Location	Utrecht, NetherlandsShow on map
Degree of Recognition	International