Figure 3 - uploaded by Ping Gong
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Representative UMI images. A, Terminal ileum segment with no inflammation. B, Right lower quadrant segment with mild inflammation. C, Terminal ileum segment with severe inflammation.
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Objectives
Crohn disease (CD) is a chronic inflammation in the digestive tract that affects millions of Americans. Bowel vascularity has important diagnostic information because inflammation is associated with blood flow changes. We recently developed an ultrasensitive ultrasound microvessel imaging (UMI) technique with high vessel sensitivity. Thi...
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Context 1
... tomographic enterographic or MRE readings of bowel segments were used as the reference standards, which revealed 21 bowel segments with no inflammation, 9 bowel segments with mild inflammation, and 46 bowel segments with severe inflammation, as listed in Table 1. Figure 3 shows 3 representative UMI images, indicating the association between blood flow growth and increased IBD activities (ie, normal, mild, and severe). The bowel segment with no inflammation was relatively avascular or hypovascular. ...
Context 2
... improved sensitivity in UMI was mainly attributed to more image frames and advanced clutter-filtering methods used for Doppler image formation. Both CFI and UMI detected significantly increased blood flows in severe CD compared to those in quiescent or mild CD (Figure 3). However, considerable overlaps existed between the VLR calculated in quiescent and mild CD using both CFI and UMI. ...
Citations
... Combining ultrafast imaging with SVD-based filtering that leverages both long temporal ensemble length (packet size) and the rich spatial information has resulted in substantially improved discrimination of blood flow and tissue clutters [5][6][7]. These techniques have demonstrated superior Doppler sensitivity to small vessels compared to conventional Doppler ultrasound, fostering a diverse applications, including functional ultrasound imaging of brain and spine, tumor evaluation, and assessment of kidney, liver, inflammatory diseases [5,[19][20][21][22]. ...
Effective clutter filtering is crucial in suppressing tissue clutter and extracting blood flow signal in Doppler ultrasound. Recent advances in eigen-based clutter filtering techniques have enabled ultrasound imaging of microvasculature without the need for contrast agents. However, simultaneously achieving fully adaptive, highly sensitive and real-time implementation of such eigen-based filtering techniques in clinical scanning scenarios for broad translation remains challenging. To address this, here we propose a fast spatiotemporal clutter filtering technique based on eigenvalue decomposition (EVD) and a novel localized data processing framework for robust and high-definition ultrasound imaging of blood flow. Unlike the existing local clutter filter that hard splits the ultrasound data into small blocks, our approach applies a series of 2D spatial Gaussian windows to the original data to generate local data subsets. This approach improves performance of flow detection while effectively avoiding undesired grid artifacts with dramatically reduced number of subsets required in local EVD filtering to shorten computation time. By leveraging the computational power of Graphics Processing Units (GPUs), we demonstrate the real-time implementation capability of the proposed approach. We also introduce and systematically evaluate several adaptive and automatic eigenvalue thresholding methods tailored for EVD-based filtering to facilitate optimization of blood flow imaging for either global or localized processing. The feasibility of the proposed clutter filtering technique is validated by experimental results from phantom and different in vivo studies, revealing robust clinical application potential. A tradeoff between improved performance and computational cost associated with the packet size and subset number in local processing is also investigated.
... More recently, an ultrasensitive ultrasound microvessel imaging (UMI) technique, able to provide a significant higher sensitivity in depicting smaller vessels compared with conventional Doppler, has been developed and compared to CT/MRI, in a pilot study of Gong et al.(Gong et al., 2020). Altered vascularization was demonstrated in case of severe inflammation, while no significant difference was found between quiescent and mild CD. ...
The evaluation of the degree of inflammation and fibrosis, intrinsic elements in intestinal wall damage of Crohn’s disease, is essential to individuate the extent of the lesions and the presence of strictures. This information will contribute to the choice of the appropriate therapeutic approach, the prediction of the response to therapy and the course of the disease. The accurate evaluation of the extent and severity of inflammation and/or fibrosis in Crohn’s disease currently requires histopathological analysis of the intestinal wall. However, in clinical practice and research, transmural assessment of the intestinal wall with cross sectional imaging is increasingly used for this purpose. The B-mode ultrasonograhic characteristics of the intestinal wall, the assessment of its vascularization by color Doppler and I.V. contrast agents, and the evaluation of the mechanical and elastic properties by sonoelastography, may provide useful and accurate information on the severity and extent of inflammation and intestinal fibrosis in Crohn’s disease. The purpose of this review is to provide an update on current sonographic methods to discriminate inflammation and fibrosis in Crohn’s disease.
... One-third of all patients are under 20 years of age. The reported incidence and prevalence rates are 4.8 -6.8 / 100.000 and 17.9 -30.7 / 100.000, respectively (Gong et al., 2020). ...
... One-third of all patients are under 20 years of age. The reported incidence and prevalence rates are 4.8 -6.8 / 100.000 and 17.9 -30.7 / 100.000, respectively (Gong et al., 2020). ...
Background Liver microcirculation dysfunction plays a vital role in the occurrence and development of liver diseases, and thus, there is a clinical need for in vivo, noninvasive, and quantitative evaluation of liver microcirculation. Purpose To evaluate the feasibility of ultrasensitive US microvessel imaging (UMI) in the visualization and quantification of hepatic microvessels in healthy and cirrhotic rats. Materials and Methods In vivo studies were performed to image hepatic microvasculature by means of laparotomy in Sprague-Dawley rats (five cirrhotic and five control rats). In vivo conventional power Doppler US and ex vivo micro-CT were performed for comparison. UMI-based quantifications of perfusion, tortuosity, and integrity of microvessels were compared between the control and cirrhotic groups by using the Wilcoxon test. Spearman correlations between quantification parameters and pathologic fibrosis, perfusion function, and hepatic hypoxia were evaluated. Results UMI helped detect minute vessels below the liver capsule, as compared with conventional power Doppler US and micro-CT. With use of UMI, lower perfusion indicated by vessel density (median, 22% [IQR, 20%-28%] vs 41% [IQR, 37%-46%]; P = .008) and fractional moving blood volume (FMBV) (median, 6.4% [IQR, 4.8%-8.6%] vs 13% [IQR, 12%-14%]; P = .008) and higher tortuosity indicated by the sum of angles metric (SOAM) (median, 3.0 [IQR, 2.9-3.0] vs 2.7 [IQR, 2.6-2.9]; P = .008) were demonstrated in the cirrhotic rat group compared with the control group. Vessel density (r = 0.85, P = .003), FMBV (r = 0.86, P = .002), and median SOAM (r = -0.83, P = .003) showed strong correlations with pathologically derived vessel density labeled with dextran. Vessel density (r = -0.81, P = .005) and median SOAM (r = 0.87, P = .001) also showed strong correlations with hepatic tissue hypoxia. Conclusion Contrast-free ultrasensitive US microvessel imaging provided noninvasive in vivo imaging and quantification of hepatic microvessels in cirrhotic rat liver. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Fetzer in this issue.
The morphological features of vasculature in diseased tissue differ significantly from those in normal tissue. Therefore, vasculature quantification is crucial for disease diagnosis and staging. Ultrasound microvessel imaging (UMI) with ultrafast ultrasound acquisitions has been determined to have potential in clinical applications given its superior sensitivity in blood flow detection. However, the presence of spatial-dependent noise caused by a low imaging signal-to-noise ratio and incoherent clutter artifacts caused by moving hyperechoic scatterers degrades the performance of UMI and the reliability of vascular quantification. To tackle these issues, we proposed an improved UMI technique along with an adaptive vessel segmentation workflow for robust vessel identification and vascular feature quantification. A previously proposed sub-aperture cross-correlation technique and a normalized cross-correlation technique were applied to equalize the spatially dependent noise level and suppress the incoherent clutter artifact. A square operator and non-local means filter were then used to better separate the blood flow signal from residual background noise. On the de-noised ultrasound microvessel image, an automatic and adaptive vessel segmentation method was developed based on the different spatial patterns of blood flow signal and background noise. The proposed workflow was applied to a CIRS phantom, to a Doppler flow phantom and to an inflammatory bowel, kidney and liver, to validate its feasibility. Results revealed that automatic adaptive, and robust vessel identification performance can be achieved using the proposed method without the subjectivity caused by radiologists/operators.
