On the truncation of time frequency distributions to improve the computational performance in the estimation of fundamental parameters of a Doppler ultrasound blood flow signal

Evaluation of blood-flow Doppler ultrasound spectral content is currently performed on clinical diagnosis. Since mean frequency and bandwidth spectral parameters are determinants on the quantification of stenotic degree, more precise estimators than the conventional Fourier transform should be seek. This paper summarizes studies led by the author in this field, as well as the strategies used to implement the methods in real-time. Regarding stationary and nonstationary characteristics of the blood-flow signal, different models were assessed. When autoregressive and autoregressive moving average models were compared with the traditional Fourier based methods in terms of their statistical performance while estimating both spectral parameters, the Modified Covariance model was identified by the cost/benefit criterion as the estimator presenting better performance. The performance of three time-frequency distributions and the Short Time Fourier Transform was also compared. The Choi–Williams distribution proved to be more accurate than the other methods. The identified spectral estimators were developed and optimized using high performance techniques. Homogeneous and heterogeneous architectures supporting multiple instruction multiple data parallel processing were essayed. Results obtained proved that real-time implementation of the blood-flow estimators is feasible, enhancing the usage of more complex spectral models on other ultrasonic systems.

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AB0425 PRELIMINARY EVALUATION OF THE SURAL NERVE USING 24-MHZ ULTRASOUND: A NEW APPROACH TO EVALUATE SURAL NEUROPATHY OF SJOGREN’S SYNDROME PATIENTS

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2020-eular.4176 ◽

2020 ◽

Vol 79 (Suppl 1) ◽

pp. 1512.2-1512

Author(s):

F. Liu ◽

J. Zhu ◽

S. Zhang ◽

D. LI ◽

F. Liu ◽

...

Keyword(s):

Blood Flow ◽

Sjögren’S Syndrome ◽

Sural Nerve ◽

Sjögren's Syndrome ◽

Sjogren’S Syndrome ◽

Sjogren's Syndrome ◽

Primary Sjögren’S Syndrome ◽

Flow Signal ◽

Blood Flow Signal ◽

Sjögren‘S Syndrome

Background:Peripheral neuropathy is one of the most frequent extraglandular manifestations of primary Sjögren’s syndrome (pSS). The diagnosis of peripheral neuropathy complications of pSS is based primarily on careful neurologic examination and electrodiagnostic tests. The value of ultrasound in peripheral nerve has been recognized. However, little clinical researches have focused specifically on cutaneous nerve of pSS.Objectives:To evaluate the morphological changes of sural nerve in patients with pSS by high-frequency ultrasound.Methods:The prospective study subjects consisted of 31 consecutive pSS patients underwent sural nerve biopsy and 30 healthy volunteers as controls. The ultrasonic presentations of the fascicle, perineurium, epineurium of sural nerve were observed, and the cross-sectional areas (CSA) of the sural nerves was measured.Results:Among the 21 sural nerves confirmed by pathology, all showed the thickening of the perineurium and epineurium (Figure 1-2), and abnormal blood flow signal in perineurium or epineurium in 14 cases (Figure 2). The mean CSAs were (1.41±0.44) mm2 for the control group, and (1.58±0.48) mm2 for the case group (P>0.05). In addition, the abnormal blood flow signal in sural nerve correlated with disease activity.Conclusion:This study indicated that high-frequency ultrasound may be a valuable tool for evaluating cutaneous nerve neuropathy of Sjogren’s syndrome patients.References:[1]Vitali C, Bombardieri S, Jonsson R, Moutsopoulos HM, Alexander EL, Carsons SE, et al. Classification criteria for Sjögren’s syndrome: a revised version of the European criteria proposed by the American-European Consensus Group. Ann Rheum Dis. 2002;61(6):554-8.[2]Terrier B, Lacroix C, Guillevin L, Hatron PY, Dhote R, Maillot F, et al. Diagnostic and prognostic relevance of neuromuscular biopsy in primary Sjögren’s syndrome-related neuropathy. Arthritis Rheum.2007;57(8):1520-9.[3]McCoy SS, Baer AN. Neurological Complications of Sjögren’s Syndrome: Diagnosis and Management. Curr Treatm Opt Rheumatol. 2017;3(4):275-88.[4]Carvajal Alegria G, Guellec D, Devauchelle-Pensec V, Saraux A. Is there specific neurological disorders of primary Sjögren’s syndrome? Joint Bone Spine. 2015;82(2):86-9.Figure 1.Transverse sonograms of the sural nerve (arrows) V: indicates lesser saphenous veinFigure 2.Longitudinal sonograms of the sural nerve (arrows) The sonogram of sural nerve showed abnormal blood flow signal. V indicates lesser saphenous vein.Acknowledgments:This work was partly supported by National Natural Science Foundation of China (No. 81701712).Disclosure of Interests: :None declared

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