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Comparison of B-mode, M-mode and echo-tracking methods for measurement of the arterial distension waveform

ULTRASOUND IN MEDICINE AND BIOLOGY 1997年第6期23卷 879-887页

作者： Stadler, RW Taylor, JA Lees, RS BOSTON HEART FDN CAMBRIDGEMA 02142 HARVARD UNIV MITDIV HLTH SCI & TECHNOLCAMBRIDGEMA 02142 HARVARD UNIV SCH MEDDIV AGINGBOSTONMA 02142 BETH ISRAEL HOSP HEBREW REHABIL CTR AGEDBOSTONMA 02142

Measurements of arterial diameter throughout the cardiac cycle (i.e., the arterial distension waveform) are conducted increasingly to study mechanical properties of the arterial wall and changes associated with disease. The distension waveform of peripheral arteries can be measured noninvasively via ultrasonic echo tracking, M-mode imaging, and B-mode imaging, Of these, echo tracking is the most popular method because of its single micrometer resolution during continuous measurements under ideal conditions, However, high resolution within continuous measurements does not imply high reproducibility between measurements. Therefore, we compared repeated measurements of the amplitude of common carotid artery distension in 26 subjects, obtained sequentially in random order by: 1. Off-line echo tracking of digitized radiofrequency ultrasound;2. M-mode imaging with automated edge detection;and 3. 30-Hz B-mode imaging with automated edge detection and model-based diameter estimation. In each case, the transducer was hand-held and was removed from the neck between repeated measurements. The amplitude of arterial distension was estimated from the serial diameter measurements by maximum likelihood (ML) estimation, by least-squares fit of a Fourier series model, and by application of a cubic smoothing spline. Within continuous measurements, the standard deviation of the ML distension amplitude for neighboring cardiac cycles was significantly smaller (p < 0.05) with echo-tracking (0.023 mm) than with the B-mode (0.036 mm) or M-mode (0.074 mm) methods. However, between discontinuous measurements on the same subject, the standard deviation of the ML distension amplitude was similar for the echo-tracking (0.076 mm) and B-mode (0.073 mm) methods. The Fourier series model and the cubic smoothing spline slightly reduced the standard deviation of the B-mode and M-mode distension amplitudes, but also reduced the mean amplitude estimate. On the basis of this relative comparison of method

关键词： ultrasound ultrasonic echo tracking computer-assisted image processing arterial distensibility arterial diameter

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Is Proximal Tibia Sufficient for Accurate Measurement of Tibial Slope An-gles on Three-dimensional Tomography-based Anatomical Models?

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CURRENT MEDICAL IMAGING 2021年第12期17卷 1419-1424页

作者： Tanoglu, Oguzhan Subasi, Izzet Ozay Gokgoz, Mehmet Burak Arican, Gokhun Erzincan Binali Yildirim Univ Dept Orthoped & Traumatol Erzincan Turkey Sivas Numune Hosp Dept Orthoped & Traumatol Sivas Turkey Mugla Sitki Kocman Univ Dept Orthoped & Traumatol Mugla Turkey

Background: Tibial slope measurements performed using only the proximal part of tibia ignore the native tibial anatomical axis. Our first aim is to measure the native medial, lateral and total tibial slope angles of gender groups using the whole tibial anatomical axis on computerized tomography-based three-dimensional anatomical models. The second aim is to determine the correlation between proximal and whole tibial anatomical axis for measurement of medial, lateral, and total tibial slope angles. Methods: We randomly selected 100 females and 100 males between 18-60 years of age. Three-dimensional anatomical models of right and left tibia were created. The gender-specific differences of medial, lateral, and total tibial slope angles according to proximal and whole tibial anatomical axis were measured. Correlation coefficients (r) of medial, lateral, and total tibial slope angles measured with proximal and whole tibial anatomical axis were calculated. Results: The mean age was 47.1 years. A statistically significant difference was observed between female (7.1 +/- 3) and male (8.2 +/- 2.5) groups in terms of mean lateral tibial slope angles according to the whole tibial anatomical axis (p=0.008). A strong correlation between proximal and whole tibial anatomical axis for all tibial slope angle measurements was detected. Conclusion: The method we determined for 3D measurement of medial, lateral and total tibial slope angles using proximal tibial anatomical axis has a strong correlation with slope angles measured in accordance with the whole tibial anatomical axis. Our 3D tibial slope angle measurement method on the proximal tibia has high reliability and could be used in the daily practice.

关键词： Three-dimensional imaging unicondylar knee arthroplasty ACL injury total knee arthroplasty computer-assisted image processing osteotomy anatomical models tomography

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Validation of 3D reconstructions of a mimicked femoral artery with an ultrasound imaging robotic system

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MEDICAL PHYSICS 2010年第7期37卷 3868-3879页

作者： Janvier, Marie-Ange Soulez, Gilles Allard, Louise Cloutier, Guy CRCHUM Lab Biorheol & Med Ultrason Montreal PQ H2L 2W5 Canada Univ Montreal Inst Biomed Engn Montreal PQ H3T 1J4 Canada Univ Montreal Dept Radiol Radiooncol & Nucl Med Montreal PQ H3T 1J4 Canada CHUM Dept Radiol Montreal PQ H2L 4M1 Canada

Purpose: The degree of stenosis is the most important criterion to assess peripheral arterial disease manifested by atherosclerosis mainly in lower limb arteries. Ultrasound (U.S.) imaging offers low-cost, safe, and convenient options to evaluate this disease, but most U.S. freehand approaches cannot optimally locate stenoses and map lower limb arterial geometries. A 3D-U.S. imaging robotic system that can control and standardize image acquisition by scanning typically encountered diseased arterial lower limb segments is presented and validated with phantoms. Methods: A Z-phantom calibration procedure was used to characterize spatial transformation of the U.S. probe image plane for different clinical image acquisition settings. Moreover, the accuracy of the calibration transform to reconstruct a lower-limb-mimicking vessel geometry was evaluated with a vascular phantom. Results: A 3D calibration precision of 0.47 +/- 0.27 mm was achieved. Reconstruction errors were less than 1.74 +/- 0.08 mm in all 3D vessel representations and the cross-sectional areas of each image section were close to those of gold standard phantom measures. The best reconstruction accuracy (smallest error) was 0.40 +/- 0.03 mm. Conclusion: Altogether, these results demonstrate the potential of the robotic scanner to adequately represent lower limb vessels for the clinical evaluation of stenoses. (C) 2010 American Association of Physicists in Medicine. [DOI: 10.1118/1.3447721]

关键词： 3D-ultrasound imaging system cardiovascular imaging robotics ultrasound probe calibration 3D-ultrasound reconstruction precision and accuracy evaluations calibration phantom lower limb arterial disease computer-assisted image processing

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Doppler ultrasound compared with electrocardiogram and pulse oximetry cardiac triggering: A pilot study

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MAGNETIC RESONANCE IN MEDICINE 2015年第5期74卷 1257-1265页

作者： Kording, Fabian Schoennagel, Bjoern Lund, Gunnar Ueberle, Friedrich Jung, Caroline Adam, Gerhard Yamamura, Jin Univ Med Ctr Hamburg Eppendorf Ctr Radiol & Endoscopy Dept Diagnost & Intervent Radiol D-20246 Hamburg Germany Hamburg Univ Appl Sci Hamburg Germany

PurposeAccurate triggering of the cardiac cycle is mandatory for optimal image acquisition and thus diagnostic quality in cardiac magnetic resonance imaging. The purpose of this work was to evaluate Doppler ultrasound as an alternative trigger method in cardiac MRI. MethodsSteady-state free precession (SSFP) 2D cine CMR was performed in 11 healthy subjects at 1.5T. Doppler ultrasound (DUS), electrocardiogram (ECG) and pulse oximetry (POX) were used for cardiac triggering. DUS peak detection was verified in comparison to ECG. Quantitative analysis of image quality of each gating method was determined by calculating endocardial border sharpness (EBS) and left ventricular (LV) function parameters and compared with ECG. ResultsMean difference between DUS and ECG in detected RR intervals was 0.04 63 ms (r = 0.96). Trigger jitter was not different between ECG and DUS (P = 0.15) but significant different between ECG and POX (P = 0.01). EBS was similar between each method (3.1 +/- 0.2 / 2.6 +/- 0.2 / 2.9 +/- 0.2 pixel). Mean differences in stroke volume were not significantly different with -1 +/- 7 mL (ECG/DUS, P = 0.9) and 2 +/- 10 mL (ECG/POX, P = 0.8). ConclusionCine cardiac MRI using DUS was successfully demonstrated. DUS triggering is an alternative method for cardiac MRI and may be applied in a clinical setting. Magn Reson Med 74:1257-1265, 2015. (c) 2014 Wiley Periodicals, Inc.

关键词： cine magnetic resonance imaging Doppler ultrasound cardiac-gated imaging techniques oximetry electrocardiogram computer-assisted image processing

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Clinical Value of Radiofrequency Ultrasonic Local Estimators in Classifying Breast Lesions

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JOURNAL OF ULTRASOUND IN MEDICINE 2013年第1期32卷 83-92页

作者： Wang, Jian Kang, Chunsong Liu, Xiaofang Li, Tingting Wang, Yu Feng, Tinghua Li, Zhaojun Xue, Jiping Shi, Kailing Shanxi Med Univ Dept Ultrasound Hosp 1 Taiyuan Shanxi Peoples R China Shanxi Acad Med Sci Dept Ultrasound Taiyuan 030032 Shanxi Peoples R China Shanxi Dayi Hosp Taiyuan 030032 Shanxi Peoples R China

Objectives-We sought to summarize the features of radiofrequency ultrasonic local estimator (RULES) images of benign and malignant masses and to explore the diagnostic value of RULES scores to identify breast lumps. Methods-A total of 81 women with a mean age +/- SD of 41.33 +/- 12.03 years (range, 19-68 years) with 82 lesions seen at our hospital were included in this study. Inclusion criteria were Breast Imaging Reporting and Data System grade 2 to 5 breast lesions, preoperative 2-dimensional (2D) ultrasound (US) examinations and RULES image acquisition, no treatment before the US examinations, surgical resection in our hospital, and histopathologic results. Each RULES characteristic was scored on the basis of expected values for malignant characteristics, and this RULES scoring system was assessed by a receiver operating characteristic curve. Results-Of the 82 lesions, 45 were benign, and 37 were malignant. Malignancy was associated with multiple colors, red as the main color, colors distributed in 3 or more locations, aggregated colors, and more than half of the area filled with colors. A RULES score of 7 had the highest sum of sensitivity (67.6%) and specificity (95.6%) and the highest accuracy (82.9%) for diagnosis of malignancy. When 2D US imaging a Breast Imaging Reporting and Data System category of 4 was combined with a RULES score of 4 to detect breast cancer, the sensitivity was 83.8%;the specificity was 93.3%;and the accuracy increased to 89.0%. Conclusions-The use of RULES images and characteristics is helpful in differentiating benign and malignant breast lesions. Diagnostic accuracy can be improved by combining 2D US imaging and RULES.

关键词： breast lesions breast neoplasms computer-assisted image processing diagnosis ultrasound

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The role of the subchondral layer in osteonecrosis of the femoral head: analysis based on HR-QCT in comparison to MRI findings

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ACTA RADIOLOGICA 2019年第4期60卷 501-508页

作者： Kolb, Alexander R. Patsch, Janina M. Vogl, Wolf-Dieter Benca, Emir Stelzeneder, David Windhager, Reinhard Hofstaetter, Jochen G. Med Univ Vienna Dept Orthoped Waehringer Gurtel 18-20 A-1090 Vienna Austria Med Univ Vienna Dept Radiol & Nucl Med Vienna Austria Med Univ Vienna Dept Biomed Imaging & Image Guided Therapy CIR Computat Imaging Res Lab Vienna Austria

Background Non-traumatic avascular osteonecrosis of the femoral head (ONFH) is a severe disease causing destruction of the hip joint, often necessitating total hip arthroplasty (THA) even in young patients. Magnetic resonance imaging (MRI) is commonly used for diagnosis of ONFH, but provides limited insight into the subchondral bone microstructure. Purpose To analyze routine MRI findings in comparison to high-resolution quantitative computed tomography (HR-QCT) with a special focus on the subchondral layer and to estimate the importance of differences determining the indication for THA. Material and Methods Twelve patients with ONFH were included before THA. Preoperative MRI and HR-QCT of the retrieved femoral heads were aligned using a registration algorithm. Pathological findings and trabecular bone parameters in matched areas were analyzed by two readers. McNemar, marginal homogeneity test, and Pearson's correlation coefficient were used for comparison. Results Subchondral delamination was found in nine cases on HR-QCT, but missed or underestimated in all but one case on MRI (P = 0.016). Chondral discontinuity was found in all cases on HR-QCT and in two cases on MRI (P = 0.016). Areas of complete bone resorption on HR-QCT were linked to high signal intensity on 3D gradient-echo MRI sequences with water-selective excitation, while there was no correlation between trabecular bone parameters and MRI signal intensities in other areas (P = 0.304). Conclusion Subchondral delamination, subchondral resorption, and chondral discontinuity are found frequently in advanced stages of ONFH. These lesions tend to be underestimated on conventional MRI. Our results support the importance of CT imaging in the evaluation of ONFH.

关键词： Femur head necrosis magnetic resonance imaging MRI multimodal imaging diagnostic imaging computer-assisted image processing

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Three-dimensional echocardiography paves the way toward virtual reality

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ULTRASOUND IN MEDICINE AND BIOLOGY 2000年第7期26卷 1065-1074页

作者： Bruining, N Lancée, C Roelandt, JRTC Bom, N Erasmus Univ Erasmus Med Ctr Rotterdam Dept Cardiol Thoraxctr NL-3015 GD Rotterdam Netherlands Interuniv Cardiol Inst Rotterdam Netherlands

The heart is a three-dimensional (3-D) object and, with the help of 3-D echocardiography (3-DE), it can be shown in a realistic fashion. This capability decreases variability in the interpretation of complex pathology among investigators, Therefore, it is likely that the method will become the standard echocardiography examination in the future. The availability of volumetric data sets allows retrieval of an infinite number of cardiac cross-sections. This results in more accurate and reproducible measurements of valve areas, cardiac mass and cavity volumes by obviating geometric assumptions. Typical 3-DE parameters, such as ejection fraction, flow jets, myocardial perfusion and LV wall curvature, may become important diagnostic parameters based on 3-DE. However, the freedom of an infinite number of cross-sections of the heart can result in an often-encountered problem of being "lost in space" when an observer works on a 3-DE image data set. Virtual reality computing techniques in the form of a virtual heart model can be useful by providing spatial "cardiac" information, With the recent introduction of relatively low cost portable echo devices, it is envisaged that use of diagnostic ultrasound (US) will be further boosted. This, in turn, will require further teaching facilities. Coupling of a cardiac model with true 3-D echo data in a virtual reality setting may be the answer. (C) 2000 World Federation for Ultrasound in Medicine & Biology.

关键词： echocardiography three-dimensional ultrasound computer-assisted image processing magnetic position sensor freehand acquisition virtual reality

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Advanced very low bit rate video coding using preferential pattern selection algorithms

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JOURNAL OF RESEARCH AND PRACTICE IN INFORMATION TECHNOLOGY 2005年第3期37卷 285-295页

作者： Paul, M Murshed, M Monash Univ Gippsland Sch Comp & IT Churchill Vic Australia

In the context of very low bit-rate video coding, pre-defined fixed pattern representations of moving regions in blocked-based motion estimation and compensation has become increasingly attractive over H.264 as the former represents an MB by a smaller size moving region covered by the best available pattern that approximates the shape of the region more closely and hence, requiring no extra motion vector, which is not the case with the latter. But fixed set patterns sometimes fail to code efficiently for all video sequences. In this paper a novel idea of selecting a subset of best-matched patterns through preferential selection technique is developed by presenting two algorithms, Variable Pattern Selection (VPS) and Extended VPS (EVPS) for an initial pattern codebook size of 32 using a new parametric macroblock classification definition and a new similarity metric. The complexity analysis confirmed that EVPS guaranteed to be nearly six times faster than VPS, with the peak performance providing an improvement factor of nine times. The overall performance of EVPS is identical to VPS for certain parameters but on average, 0.2dB and 0.8dB better than the contemporary algorithm using fixed set patterns and Advanced Video coding standard (H.264) respectively, for the same. number of bits per frame. ACM Classification: 1.4.2 (Computing methodologies - image processing and computer vision - compression (coding)).

关键词： Computing methodologies image processing and computer vision Compression (coding) Video coding peak performance algorithms Computing Methodologies improvement factor motion vector Complexity Analysis computer-assisted image processing

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Automated and representative fascicle selection for computer-assisted morphometry of myelinated nerve fibres in peripheral nerves

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computerS IN BIOLOGY AND MEDICINE 2002年第1期32卷 1-11页

作者： Lindemuth, R Mink, D Ernzerhof, C Schimrigk, K Univ Saarland Fak Med Neurol Klin D-66421 Homburg Germany Univ Saarland Fak Med Frauenklin D-66421 Homburg Germany

We describe an algorithm that permits representative fascicle selection for sample acquisition from the entire cross-section of a nerve. We calculate the number of fascicles necessary for the acquisition of a given sample volume of nerve fibres from the image magnification, determine the scheme of intrafascicular sampling, and measure the (estimated) nerve fibre density. We start by storing the positions of all fascicles as coordinates of the microscope motor stage. We then recruit the needed fascicles from the file by calling them up out of the storage order with a constant interval, using the quotient of the total number of fascicles and the number of fascicles necessary to obtain the sample size for this purpose. The results obtained on the analysis of 40 specimens of sural and tibial nerves by means of the image analysis system IBAS are reported. (C) 2002 Elsevier Science Ltd. All rights reserved.

关键词： automated morphometry computer-assisted image processing fibre distribution fibre sampling fascicle sampling myelinated fibre peripheral nerve

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In vivo coronary artery plaque assessment with computed tomography angiography: is there an impact of iterative reconstruction on plaque volume and attenuation metrics?

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ACTA RADIOLOGICA 2017年第6期58卷 660-669页

作者： Chen, Zhongyi Boldeanu, Irina Nepveu, Simon Durand, Madeleine Chin, Anne S. Kauffmann, Claude Mansour, Samer Soulez, Gilles Tremblay, Cecile Chartrand-Lefebvre, Carl Univ Montreal Med Ctr CHUM Radiol Dept Montreal PQ Canada Univ Montreal Med Ctr CHUM Med Dept Montreal PQ Canada

Background: Coronary computed tomography angiography (CTA) allows the evaluation of coronary plaque volume and low attenuation (lipid-rich) component, for plaque vulnerability assessment. Purpose: To determine the effect of iterative reconstruction (IR) on coronary plaque volume and composition. Material and Methods: Consecutive patients without coronary artery disease were prospectively enrolled for 256-slice CT. images were reconstructed with both filtered back projection (FBP) and a hybrid IR algorithm (iDose(4), Philips) levels 1, 3, 5, and 7. Coronary plaques were assessed according to predefined Hounsfield unit (HU) attenuation intervals, for total plaque and HU-interval volumes. Results: Fifty-three patients (mean age, 53.6 years) were included. Noise was significantly decreased and signal-to-noise ratio (SNR) / contrast-to-noise (CNR) were both significantly improved at all IR levels in comparison to FBP. Plaque characterization was performed in 41 patients for a total of 125 plaques. Total plaque volume ranged from 104.4 +/- 120.7 to 107.4 +/- 128.9 mm(3) and low attenuation plaque component from 40.5 +/- 54.7 to 43.5 +/- 58.9 mm(3), with no statistically significant differences between all IR levels and FBP (P = 0.786 and P >= 0.078, respectively). Conclusion: IR improved image quality. Total and low attenuation plaque volumes were similar using either IR or FBP.

关键词： Algorithms coronary artery disease atherosclerotic plaque X-ray computed tomography (CT) computer-assisted image processing image reconstruction

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