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VOLUMETRIC BLOOD-FLOW MEASUREMENT BY SIMULTANEOUS DOPPLER SIGNAL AND B-MODE image-processing - A FEASIBILITY STUDY

ULTRASOUND IN MEDICINE AND BIOLOGY 1995年第4期21卷 481-492页

作者： WILLINK, R EVANS, DH UNIV LEICESTER FAC MEDDIV MED PHYSLEICESTERLEICSENGLAND

A system is described for the estimation of volumetric flow in arteries in real time by the simultaneous processing of the audio output of a commercial ultrasound scanner carrying the Doppler signal, and the video output carrying B-mode images of the lateral view of the artery. These images are processed to provide estimates of instantaneous internal vessel diameter. Combination with the relevant estimates of spatial mean velocity provides estimates of instantaneous volumetric flow. The major limitations of the system are the low rate of production of the B-mode images (17 Hz), the limited computing power and the need to tilt the transducer to produce an acceptably low Doppler angle, This tilting diminishes the quality of the imaging echoes from the arterial walls, making diameter measurement difficult. In principle, this approach to flow measurement represents an improvement on the conventional duplex technique where a single estimate of diameter is used. In practice, its value is limited by current transducer capabilities.

关键词： BLOOD FLOW VELOCITY ULTRASONIC IMAGING DOPPLER ULTRASOUND computer-assisted image processing computer-assisted SIGNAL processing DIGITAL SIGNAL processing ARTERIES CAROTID ARTERIES ULTRASONOGRAPHY ULTRASONICS,

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Three-dimensional reconstruction of light microscopy image sections： present and future

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Frontiers of Medicine 2015年第1期9卷 30-45页

作者： Yuzhen Wang Rui Xu Gaoxing Luo Jun Wu Institute of Burn Research Southwest Hospital State Key Laboratory of Trauma Burns and Combined lnjury Chongqing Key Laboratory for Diseases Proteomics the Third Military Medical University Chongqing 400038 China

Three-dimensional （3D） image reconstruction technologies can reveal previously hidden microstruc-tures in human tissue. However, the lack of ideal, non-destructive cross-sectional imaging techniques is still a problem. Despite some drawbacks, histological sectioning remains one of the most powerful methods for accurate high-resolution representation of tissue structures. computer technologies can produce 3D representations of interesting human tissue and organs that have been serial-sectioned, dyed or stained, imaged, and segmented for 3D visualization. 3D reconstruction also has great potential in the fields of tissue engineering and 3D printing. This article outlines the most common methods for 3D tissue section reconstruction. We describe the most important academic concepts in this field, and provide critical explanations and comparisons. We also note key steps in the reconstruction procedures, and highlight recent progress in the development of new reconstruction methods.

关键词： microtomy 3D imaging computer-assisted image processing 3D printing tissue scaffold

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Characterization of vascular structures and skin bruises using hyperspectral imaging, image analysis and diffusion theory

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JOURNAL OF BIOPHOTONICS 2010年第1-2期3卷 53-65页

作者： Randeberg, Lise Lyngsnes Larsen, Eivind La Puebla Svaasand, Lars Othar Norwegian Univ Sci & Technol Dept Elect & Telecommun N-7491 Trondheim Norway

Hyperspectral imaging, image analysis and diffusion theory were used to visualize skin vasculature and to monitor the development of fresh skin bruises. Bruises were inflicted in a porcine model, and the development of the hemorrhage was monitored using white light hyperspectral imaging (400-1000 nm). Hyperspectral images front human volunteers were also included in the study. Statistical image analysis was used to classify bruised regions and to visualize the skin vasculature. Biopsies were collected from the animals to reveal the true depth of the bruising. A three-layer diffusion model and an analytic hemoglobin transport model were used to model the reflectance spectral from the images. The results show that hyperspectral images contain, depth information, and that the approximate depth and extent of bruises can be retrieved using a combination of statistic image analysis and diffusion theory. This technique also shows potential to visualize vascular structures in human skin. [GRAPHICS] Bruised skin classified by spectral angle mapping (C) 2010 by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

关键词： diagnostic imaging computer-assisted image processing contusions near-infrared spectroscopy

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Validation of mitosis counting by automated phosphohistone H3 (PHH3) digital image analysis in a breast carcinoma tissue microarray

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PATHOLOGY 2015年第4期47卷 329-334页

作者： Dessauvagie, B. F. Thomas, C. Robinson, C. Frost, F. A. Harvey, J. Sterrett, G. F. QEII Med Ctr PathWest Lab Med Dept Anat Pathol Nedlands WA 6009 Australia Univ Western Australia Sch Pathol & Lab Med Crawley WA Australia Univ Western Australia Sch Med & Pharmacol Crawley WA Australia

Mitosis counting in H&E stained sections is the most informative constituent of the Nottingham histological grade in breast carcinoma prognosis. Phosphohistone H3 (PHH3) immunohistochemistry (IHC) is a highly specific marker of mitoses, with practical application in identifying mitoses in poorly fixed or distorted tissue and is of prognostic significance in breast carcinoma. Our aim was to assess methods of PHH3 IHC mitosis counting in a tissue microarray (TMA) of 2mm cores from 36 resected breast carcinomas. Mitoses in H&E and PHH3 stained slides were manually scored by pathologist consensus and expressed as counts/2 mm(2). PHH3 stained cores were also evaluated by automated digital image analysis (DIA). Results were compared using Spearman correlation. A strong and significant correlation was observed between manual PHH3 and manual H&E mitotic counts (correlation = 0.81;p< 0.0001) and between automated PHH3 DIA and manual H&E mitotic counts (correlation = 0.79;p< 0.0001). More mitoses were identified with PHH3 IHC than with H&E. Manual and DIA PHH3 counts were strongly and significantly correlated (correlation = 0.83;p< 0.0001) and of similar absolute values. PHH3 DIA is a valid alternative to manual counting with potential application in breast cancer reporting and prognostication.

关键词： Breast carcinoma computer-assisted image processing digital image analysis immunohistochemistry mitotic index PHH3 phosphohistone H3 tissue microarray TMA

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A comparative study of new and current methods for dental micro-CT image denoising

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DENTOMAXILLOFACIAL RADIOLOGY 2016年第3期45卷 art. no. 20150302-art. no. 20150302页

作者： Shahmoradi, Mahdi Lashgari, Mojtaba Rabbani, Hossein Qin, Jie Swain, Michael Univ Sydney Fac Dent Biomat & Bioengn Sydney NSW 2006 Australia Isfahan Univ Med Sci Fac Adv Med Technol Dept Biomed Engn Esfahan Iran Isfahan Univ Med Sci Med Image & Signal Proc Res Ctr Esfahan Iran Jilin Univ Stomatol Hosp Dept Implantol Changchun 130023 Jilin Peoples R China Kuwait Univ Hlth Sci Ctr Fac Dent Dept Bioclin Sci Kuwait Kuwait

Objectives: The aim of the current study was to evaluate the application of two advanced noise-reduction algorithms for dental micro-CT images and to implement a comparative analysis of the performance of new and current denoising algorithms. Methods: Denoising was performed using gaussian and median filters as the current filtering approaches and the block-matching and three-dimensional (BM3D) method and total variation method as the proposed new filtering techniques. The performance of the denoising methods was evaluated quantitatively using contrast-to-noise ratio (CNR), edge preserving index (EPI) and blurring indexes, as well as qualitatively using the double-stimulus continuous quality scale procedure. Results: The BM3D method had the best performance with regard to preservation of fine textural features (CNREdge), non-blurring of the whole image (blurring index), the clinical visual score in images with very fine features and the overall visual score for all types of images. On the other hand, the total variation method provided the best results with regard to smoothing of images in texture-free areas (CNRTex-free) and in preserving the edges and borders of image features (EPI). Conclusions: The BM3D method is the most reliable technique for denoising dental micro-CT images with very fine textural details, such as shallow enamel lesions, in which the preservation of the texture and fine features is of the greatest importance. On the other hand, the total variation method is the technique of choice for denoising images without very fine textural details in which the clinician or researcher is interested mainly in anatomical features and structural measurements.

关键词： noise dental X-ray microtomography image quality enhancement computer-assisted image processing

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Refined tooth and pulp segmentation using U-Net in CBCT image

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DENTOMAXILLOFACIAL RADIOLOGY 2021年第6期50卷 1-8页

作者： Duan, Wei Chen, Yufei Zhang, Qi Lin, Xiang Yang, Xiaoyu Tongji Univ Coll Elect & Informat Engn Shanghai 201804 Peoples R China Tongji Univ Dept Endodont Shanghai Engn Res Ctr Tooth Restorat & Regenerat Sch & Hosp Stomatol Shanghai 200072 Peoples R China

Objectives: The aim of this study was extracting any single tooth from a CBCT scan and performing tooth and pulp cavity segmentation to visualize and to have knowledge of internal anatomy relationships before undertaking endodontic therapy. Methods: We propose a two-phase deep learning solution for accurate tooth and pulp cavity segmentation. First, the single tooth bounding box is extracted automatically for both single-rooted tooth (ST) and multirooted tooth (MT). It is achieved by using the Region Proposal Network (RPN) with Feature Pyramid Network (FPN) method from the perspective of panorama. Second, U-Net model is iteratively performed for refined tooth and pulp segmentation against two types of tooth ST and MT, respectively. In light of rough data and annotation problems for dental pulp, we design a loss function with a smoothness penalty in the network. Furthermore, the multi-view data enhancement is proposed to solve the small data challenge and morphology structural problems. Results: The experimental results show that the proposed method can obtain an average dice 95.7% for ST, 96.2% for MT and 88.6% for pulp of ST, 87.6% for pulp of MT. Conclusions: This study proposed a two-phase deep learning solution for fast and accurately extracting any single tooth from a CBCT scan and performing accurate tooth and pulp cavity segmentation. The 3D reconstruction results can completely show the morphology of teeth and pulps, it also provides valuable data for further research and clinical practice.

关键词： computer-assisted image processing Tooth and pulp cavity segmentation U-Net model Cone-Beam Computed Tomography

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Deep learning reconstruction for contrast-enhanced CT of the upper abdomen: similar image quality with lower radiation dose in direct comparison with iterative reconstruction

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EUROPEAN RADIOLOGY 2021年第8期31卷 5533-5543页

作者： Nam, Ju Gang Hong, Jung Hee Kim, Da Som Oh, Jiseon Goo, Jin Mo Seoul Natl Univ Med Res Ctr Seoul Natl Univ Hosp Dept Radiol 101 Daehak Ro Seoul 03080 South Korea Seoul Natl Univ Med Res Ctr Coll Med 101 Daehak Ro Seoul 03080 South Korea Seoul Natl Univ Med Res Ctr Inst Radiat Med 101 Daehak Ro Seoul 03080 South Korea Inje Univ Coll Med Busan Paik Hosp Dept Radiol Busan 47392 South Korea Seoul Natl Univ Coll Med Canc Res Inst Seoul 03080 South Korea

Objective To evaluate the effect of a commercial deep learning algorithm on the image quality of chest CT, focusing on the upper abdomen. Methods One hundred consecutive patients who simultaneously underwent contrast-enhanced chest and abdominal CT were collected. The radiation dose was optimized for each scan (mean CTDIvol: chest CT, 3.19 +/- 1.53 mGy;abdominal CT, 7.10 +/- 1.88 mGy). Three image sets were collected: chest CT reconstructed with an adaptive statistical iterative reconstruction (ASiR-CHT;50% blending), chest CT with a deep learning algorithm (DLIR-CHT), and abdominal CT with ASiR (ASiR-ABD;40% blending). Afterwards, the images covering the upper abdomen were extracted, and image noise, the signal-to-noise ratio (SNR), and the contrast-to-noise ratio (CNR) were measured. For subjective evaluation, three radiologists independently assessed noise, spatial resolution, presence of artifacts, and overall image quality. Additionally, readers selected the most preferable reconstruction technique among three image sets for each case. Results The average measured noise for DLIR-CHT, ASiR-CHT, and ASiR-ABD was 8.01 +/- 2.81, 14.8 +/- 2.56, and 12.3 +/- 2.28, respectively (p < .001). Deep learning-based image reconstruction (DLIR) also showed the best SNR and CNR (p < .001). However, in the subjective analysis, ASiR-ABD showed less subjective noise than DLIR (2.94 +/- 0.23 vs. 2.87 +/- 0.26;p < .001), while DLIR showed better spatial resolution (2.60 +/- 0.34 vs. 2.44 +/- 0.31;p = .02). ASiR-ABD showed a better overall image quality (p = .001), but two of the three readers preferred DLIR more frequently. Conclusion With < 50% of the radiation dose, DLIR chest CT showed comparable image quality in the upper abdomen to that of dedicated abdominal CT and was preferred by most readers.

关键词： Deep learning Multidetector computed tomography computer-assisted image processing Radiation dosage image enhancement

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Diffusion-Weighted MRI of Breast Cancer: Improved Lesion Visibility and image Quality Using Synthetic b-Values

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JOURNAL OF MAGNETIC RESONANCE IMAGING 2019年第6期50卷 1754-1761页

作者： Bickel, Hubert Polanec, Stephan H. Wengert, Georg Pinker, Katja Bogner, Wolfgang Helbich, Thomas H. Baltzer, Pascal A. Med Univ Vienna Div Mol & Gender Imaging Dept Biomed Imaging & Image Guided Therapy Vienna Austria Mem Sloan Kettering Canc Ctr Breast Imaging Serv Dept Radiol 1275 York Ave New York NY 10021 USA Med Univ Vienna Dept Biomed Imaging & Image Guided Therapy High Field MR Ctr Vienna Austria

Background: Diffusion-weighted imaging (DWI) is an MRI technique with the potential to serve as an unenhanced breast cancer detection tool. Synthetic b-values produce images with high diffusion weighting to suppress residual background signal, while avoiding additional measurement times and reducing artifacts. Purpose: To compare acquired DWI images (at b = 850 s/mm(2)) and different synthetic b-values (at b = 1000-2000 s/mm(2)) in terms of lesion visibility, image quality, and tumor-to-tissue contrast in patients with malignant breast tumors. Study Type: Retrospective. Population: Fifty-three females with malignant breast lesions. Field Strength/Sequence: T(2)w, DWI EPI with STIR fat-suppression, and dynamic contrast-enhanced T(1)w at 3T. Assessment: From acquired images using b-values of 50 and 850 s/mm(2), synthetic images were calculated at b = 1000, 1200, 1400, 1600, 1800, and 2000 s/mm(2). Four readers independently rated image quality, lesion visibility, preferred b-value, as well as the lowest and highest b-value, over the range of b-values tested, to provide a diagnostic image. Statistical Tests: Medians and mean ranks were calculated and compared using the Friedman test and Wilcoxon signed-rank test. Reproducibility was analyzed by intraclass correlation (ICC), Fleiss, and Cohen's kappa. Results: Relative signal-to-noise and contrast-to-noise ratios decreased with increasing b-values, while the signal-intensity ratio between tumor and tissue increased significantly (P < 0.001). Intermediate b-values (1200-1800 s/mm(2)) were rated best concerning image quality and lesion visibility;the preferred b-value mostly lay at 1200-1600 s/mm(2). Lowest and highest acceptable b-values were 850 s/mm(2) and 2000 s/mm(2). Interreader agreement was moderate to high concerning image quality (ICC: 0.50-0.67) and lesion visibility (0.70-0.93), but poor concerning preferred and acceptable b-values (kappa = 0.032-0.446). Data Conclusion: Synthetically increased b-values may be

关键词： Breast neoplasms magnetic resonance imaging diffusion magnetic resonance imaging computer-assisted image processing

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Novel mammographic image features differentiate between interval and screen-detected breast cancer: a case-case study

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BREAST CANCER RESEARCH 2016年第1期10卷 1-10页

作者： Strand, Fredrik Humphreys, Keith Cheddad, Abbas Tornberg, Sven Azavedo, Edward Shepherd, John Hall, Per Czene, Kamila Karolinska Inst Dept Med Epidemiol & Biostat POB 281 SE-17177 Stockholm Sweden Karolinska Univ Hosp Diagnost Radiol Solna Sweden Karolinska Inst Swedish eSci Res Ctr Solna Sweden Stockholm Gotland Reg Canc Ctr Dept Canc Screening Stockholm Sweden Karolinska Inst Dept Mol Med & Surg Solna Sweden Univ Calif San Francisco UCSF Sch Med Dept Radiol & Biomed Imaging San Francisco CA 94143 USA

Background: Interval breast cancers are often diagnosed at a more advanced stage than screen-detected cancers. Our aim was to identify features in screening mammograms of the normal breast that would differentiate between future interval cancers and screen-detected cancers, and to understand how each feature affects tumor detectability. Methods: From a population-based cohort of invasive breast cancer cases in Stockholm-Gotland, Sweden, diagnosed from 2001 to 2008, we analyzed the contralateral mammogram at the preceding negative screening of 394 interval cancer cases and 1009 screen-detected cancers. We examined 32 different image features in digitized film mammograms, based on three alternative dense area identification methods, by a set of logistic regression models adjusted for percent density with interval cancer versus screen-detected cancer as the outcome. Features were forward-selected into a multiple logistic regression model adjusted for mammographic percent density, age, BMI and use of hormone replacement therapy. The associations of the identified features were assessed also in a sample from an independent cohort. Results: Two image features, 'skewness of the intensity gradient' and 'eccentricity', were associated with the risk of interval compared with screen-detected cancer. For the first feature, the per-standard deviation odds ratios were 1.32 (95 % CI: 1.12 to 1.56) and 1.21 (95 % CI: 1.04 to 1.41) in the primary and validation cohort respectively. For the second feature, they were 1.20 (95 % CI: 1.04 to 1.39) and 1.17 (95% CI: 0.98 to 1.39) respectively. The first feature was associated with the tumor size at screen detection, while the second feature was associated with the tumor size at interval detection. Conclusions: We identified two novel mammographic features in screening mammograms of the normal breast that differentiated between future interval cancers and screen-detected cancers. We present a starting point for further research into featu

关键词： Breast cancer Interval cancer Cancer screening Early detection Mammography computer-assisted image processing

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Integration of interactive three-dimensional image post-processing software into undergraduate radiology education effectively improves diagnostic skills and visual-spatial ability

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EUROPEAN JOURNAL OF RADIOLOGY 2013年第8期82卷 1366-1371页

作者： Rengier, Fabian Haefner, Matthias F. Unterhinninghofen, Roland Nawrotzki, Ralph Kirsch, Joachim Kauczor, Hans-Ulrich Giesel, Frederik L. Univ Heidelberg Hosp Dept Diagnost & Intervent Radiol D-69120 Heidelberg Germany Univ Heidelberg Hosp Dept Radiat Oncol D-69120 Heidelberg Germany Karlsruhe Inst Technol Inst Anthropomat Dept Informat D-76131 Karlsruhe Germany Heidelberg Univ Inst Anat & Cell Biol D-69120 Heidelberg Germany Univ Heidelberg Hosp Dept Nucl Med D-69120 Heidelberg Germany

Purpose: Integrating interactive three-dimensional post-processing software into undergraduate radiology teaching might be a promising approach to synergistically improve both visual-spatial ability and radiological skills, thereby reducing students' deficiencies in image interpretation. The purpose of this study was to test our hypothesis that a hands-on radiology course for medical students using interactive three-dimensional image post-processing software improves radiological knowledge, diagnostic skills and visual-spatial ability. Materials and methods: A hands-on radiology course was developed using interactive three-dimensional image post-processing software. The course consisted of seven seminars held on a weekly basis. The 25 participating fourth- and fifth-year medical students learnt to systematically analyse cross-sectional imaging data and correlated the two-dimensional images with three-dimensional reconstructions. They were instructed by experienced radiologists and collegiate tutors. The improvement in radiological knowledge, diagnostic skills and visual-spatial ability was assessed immediately before and after the course by multiple-choice tests comprising 64 questions each. Wilcoxon signed rank test for paired samples was applied. Results: The total number of correctly answered questions improved from 36.9 +/- 4.8 to 49.5 +/- 5.4 (p < 0.001) which corresponded to a mean improvement of 12.6 (95% confidence interval 9.9-15.3) or 19.8%. Radiological knowledge improved by 36.0% (p < 0.001), diagnostic skills for cross-sectional imaging by 38.7% (p < 0.001), diagnostic skills for other imaging modalities - which were not included in the course - by 14.0% (p = 0.001), and visual-spatial ability by 11.3% (p < 0.001). Conclusion: The integration of interactive three-dimensional image post-processing software into undergraduate radiology education effectively improves radiological reasoning, diagnostic skills and visual-spatial ability, and thereby even dia

关键词： Undergraduate medical education Radiology computer-assisted image processing Teaching Visual-spatial ability

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