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Correlation-based perfusion mapping using time-resolved MR angiography: A feasibility study for patients with suspicions of steno-occlusive craniocervical arteries

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EUROPEAN RADIOLOGY 2018年第11期28卷 4890-4899页

作者： Nam, Yoonho Jang, Jinhee Park, Sonya Youngju Choi, Hyun Seok Jung, So-Lyung Ahn, Kook-Jin Kim, Bum-soo Catholic Univ Korea Seoul St Marys Hosp Coll Med Dept Radiol 222 Banpo Daero Seoul 06591 South Korea

Purpose To explore the feasibility of using correlation-based time-delay (CTD) maps produced from time-resolved MR angiography (TRMRA) to diagnose perfusion abnormalities in patients suspected to have steno-occlusive lesions in the craniocervical arteries. Materials and methods Twenty-seven patients who were suspected to have steno-occlusive lesions in the craniocervical arteries underwent both TRMRA and brain single-photon emission computed tomography (SPECT). TRMRA was performed on the supra-aortic area after intravenous injection of a 0.03 mmol/kg gadolinium-based contrast agent. Time-to-peak (TTP) maps and CTD maps of the brain were automatically generated from TRMRA data, and their quality was assessed. Detection of perfusion abnormalities was compared between CTD maps and the time-series maximal intensity projection (MIP) images from TRMRA and TTP maps. Correlation coefficients between quantitative changes in SPECT and parametric maps for the abnormal perfusion areas were calculated. Results The CTD maps were of significantly superior quality than TTP maps (p < 0.01). For perfusion abnormality detection, CTD maps (kappa 0.84, 95% confidence interval [CI] 0.67-1.00) showed better agreement with SPECT than TTP maps (0.66, 0.46-0.85). For perfusion deficit detection, CTD maps showed higher accuracy (85.2%, 95% CI 66.3-95.8) than MIP images (66.7%, 46-83.5), with marginal significance (p = 0.07). In abnormal perfusion areas, correlation coefficients between SPECT and CTD (r = 0.74, 95% CI 0.34-0.91) were higher than those between SPECT and TTP (r = 0.66, 0.20-0.88). Conclusion CTD maps generated from TRMRA were of high quality and offered good diagnostic performance for detecting perfusion abnormalities associated with steno-occlusive arterial lesions in the craniocervical area.

关键词： Magnetic resonance angiography Perfusion Stenosis computer-assisted image processing Comparative study

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Automated detection of pulmonary embolism in CT pulmonary angiograms using an AI-powered algorithm

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EUROPEAN RADIOLOGY 2020年第12期30卷 6545-6553页

作者： Weikert, Thomas Winkel, David J. Bremerich, Jens Stieltjes, Bram Parmar, Victor Sauter, Alexander W. Sommer, Gregor Univ Basel Univ Hosp Basel Clin Radiol & Nucl Med Petersgraben 4 CH-4031 Basel Switzerland

Objectives To evaluate the performance of an AI-powered algorithm for the automatic detection of pulmonary embolism (PE) on chest computed tomography pulmonary angiograms (CTPAs) on a large dataset. Methods We retrospectively identified all CTPAs conducted at our institution in 2017 (n= 1499). Exams with clinical questions other than PE were excluded from the analysis (n= 34). The remaining exams were classified into positive (n= 232) and negative (n= 1233) for PE based on the final written reports, which defined the reference standard. The fully anonymized 1-mm series in soft tissue reconstruction served as input for the PE detection prototype algorithm that was based on a deep convolutional neural network comprising a Resnet architecture. It was trained and validated on 28,000 CTPAs acquired at other institutions. The result series were reviewed using a web-based feedback platform. Measures of diagnostic performance were calculated on a per patient and a per finding level. Results The algorithm correctly identified 215 of 232 exams positive for pulmonary embolism (sensitivity 92.7%;95% confidence interval [CI] 88.3-95.5%) and 1178 of 1233 exams negative for pulmonary embolism (specificity 95.5%;95% CI 94.2-96.6%). On a per finding level, 1174 of 1352 findings marked as embolus by the algorithm were true emboli. Most of the false positive findings were due to contrast agent-related flow artifacts, pulmonary veins, and lymph nodes. Conclusion The AI prototype algorithm we tested has a high degree of diagnostic accuracy for the detection of PE on CTPAs. Sensitivity and specificity are balanced, which is a prerequisite for its clinical usefulness.

关键词： Pulmonary embolism Computed tomography angiography Artificial intelligence computer-assisted image processing

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Skin changes in streptozotocin-induced diabetic rats

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BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 2017年第4期490卷 1154-1161页

作者： Moretti Andrade, Thiago Antonio Masson-Meyers, Daniela Santos Caetano, Guilherme Ferreira Terra, Vania Aparecida Ovidio, Paula Payao Jordao-Junior, Alceu Afonso Cipriani Frade, Marco Andrey Univ Sao Paulo Dept Internal Med Div Dermatol Sch Med Ribeirao Preto Av Bandeirantes 3900 BR-14049900 Ribeirao Preto SP Brazil Herminio Ometto Univ Ctr UNIARARAS Grad Program Biomed Sci Av Dr Maximiliano Baruto500 Jd Univ BR-13607339 Araras SP Brazil Univ Wisconsin Coll Hlth Sci 2400 East Hartford Avenue Milwaukee WI 53211 USA State Univ Londrina UEL Lab Mol Pathol Rod Celso Garcia CidPR-445Km 380 Londrina Parana Brazil Univ Sao Paulo Sch Med Ribeirao Preto Div Clin Nutr Dept Internal Med Av Bandeirantes 3900 BR-14049900 Ribeirao Preto SP Brazil

Diabetes can cause serious health complications, which can affect every organ of the body, including the skin. The molecular etiology has not yet been clarified for all diabetic skin conditions. Thus, this study aimed to investigate the changes of diabetes in skin compared to non-diabetic skin in rats. Fifteen days after establishing the diabetic status, skin samples from the dorsum-cervical region were harvested for subsequent analysis of alterations caused by diabetes. Our results demonstrate that diabetes stimulated higher inflammation and oxidative stress in skin, but antioxidant defense levels were lower compared to the non-diabetic group (p < 0.05). This could have been related to a decreased number of blood vessels and low expression of VEGF, eNOS and TGF-beta 1. Finally, insulin signaling proteins IRS, Akt, Shc and ERK showed a low expression in the diabetic group. Thus, our study shows that the pathology of diabetes induced immunohistopathological and biochemical skin changes compared to non-diabetic skin in rats. (C) 2017 Elsevier Inc. All rights reserved.

关键词： Skin homeostasis Diabetes mellitus Insulin pathway Inflammation Diabetic complication computer-assisted image processing

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Analysis of normal-appearing white matter of multiple sclerosis by tensor-based two-compartment model of water diffusion

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EUROPEAN RADIOLOGY 2015年第6期25卷 1701-1707页

作者： Tachibana, Yasuhiko Obata, Takayuki Yoshida, Mariko Hori, Masaaki Kamagata, Koji Suzuki, Michimasa Fukunaga, Issei Kamiya, Kouhei Yokoyama, Kazumasa Hattori, Nobutaka Inoue, Tomio Aoki, Shigeki Natl Inst Radiol Sci Res Ctr Charged Particle Therapy Inage Ku Chiba 2638555 Japan Yokohama City Univ Grad Sch Med Dept Radiol Kanazawa Ku Yokohama Kanagawa 2360004 Japan Juntendo Univ Sch Med Dept Radiol Bunkyo Ku Tokyo 1138431 Japan Juntendo Univ Sch Med Dept Neurol Bunkyo Ku Tokyo 1138431 Japan

To compare the significance of the two-compartment model, considering diffusional anisotropy with conventional diffusion analyzing methods regarding the detection of occult changes in normal-appearing white matter (NAWM) of multiple sclerosis (MS). Diffusion-weighted images (nine b-values with six directions) were acquired from 12 healthy female volunteers (22-52 years old, median 33 years) and 13 female MS patients (24-48 years old, median 37 years). Diffusion parameters based on the two-compartment model of water diffusion considering diffusional anisotropy was calculated by a proposed method. Other parameters including diffusion tensor imaging and conventional apparent diffusion coefficient (ADC) were also obtained. They were compared statistically between the control and MS groups. Diffusion of the slow diffusion compartment in the radial direction of neuron fibers was elevated in MS patients (0.121 x 10(-3) mm2/s) in comparison to control (0.100 x 10(-3) mm(2)/s), the difference being significant (P = 0.001). The difference between the groups was not significant in other comparisons, including conventional ADC and fractional anisotropy (FA) of diffusion tensor imaging. The proposed method was applicable to clinically acceptable small data. The parameters obtained by this method improved the detectability of occult changes in NAWM compared to the conventional methods.

关键词： Multiple sclerosis Diffusion tensor imaging Brain Magnetic resonance imaging computer-assisted image processing

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Segmentation and Surface Reconstruction of the Detailed Ear Structures, Identified in Sectioned images

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ANATOMICAL RECORD-ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY 2011年第4期294卷 559-564页

作者： Jang, Hae Gwon Chung, Min Suk Shin, Dong Sun Park, Seung Kyu Cheon, Keun Soo Park, Hyo Seok Park, Jin Seo Dongguk Univ Dept Anat Coll Med Gyeongju 780714 South Korea Ajou Univ Multimedia & Comp Architecture Lab Grad Sch Informat & Commun Suwon 443749 South Korea Ajou Univ Dept Anat Sch Med Suwon 443749 South Korea Dongguk Univ Dept Obstet & Gynecol Coll Med Gyeongju 780714 South Korea

The structure of the ear, which intervenes between gross anatomy and histology in size, can be best understood by means of three-dimensional (3D) surface models on a computer. Furthermore, surface models are the source of interactive simulation for clinical trials, such as tympanoplasty. The objective of this research was to elaborate the surface models of detailed ear structures, which contribute to learning anatomy or the practice of otology. We produced sectioned images of a cadaver head (pixel size, 0.1 mm;48-bit color). In the sectioned images, the external, middle, and internal ear structures and other related components were delineated on Photoshop to acquire segmented images at 0.5-mm intervals. Segmented images of each structure were stacked, and the surface was reconstructed to generate a 3D-surface model on commercial software. Thirty surface models showed fine ear topographic anatomy (e. g., semicircular ducts), as expected. Herein, we present the corresponding sectioned images, segmented images, and surface models of ear structures that will be released together. It is hoped that these image data will stimulate the development of medical simulations. The efficient technique of segmentation and surface reconstruction enables the manufacture of surface models from other serial images (e. g., CTs and MRIs). Anat Rec, 294: 559-564, 2011. (C) 2011 Wiley-Liss, Inc.

关键词： ear cross-sectional anatomy computer-assisted image processing three-dimensional imaging anatomic models

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Towards a Visualizable, De-identified Synthetic Biomarker of Human Movement Disorders

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JOURNAL OF PARKINSONS DISEASE 2022年第7期12卷 2085-2096页

作者： Hu, Hao Xiao, Dongsheng Rhodin, Helge Murphy, Timothy H. Univ British Columbia Dept Psychiat Kinsmen Lab Neurol Res Detwiller Pavil Vancouver BC Canada Univ British Columbia Djavad Mowafaghian Ctr Brain Hlth Vancouver BC Canada Univ British Columbia Dept Comp Sci Vancouver BC Canada

Human motion analysis has been a common thread across modern and early medicine. While medicine evolves, analysis of movement disorders is mostly based on clinical presentation and trained observers making subjective assessments using clinical rating scales. Currently, the field of computer vision has seen exponential growth and successful medical applications. While this has been the case, neurology, for the most part, has not embraced digital movement analysis. There are many reasons for this including: the limited size of labeled datasets, accuracy and nontransparent nature of neural networks, and potential legal and ethical concerns. We hypothesize that a number of opportunities are made available by advancements in computer vision that will enable digitization of human form, movements, and will represent them synthetically in 3D. Representing human movements within synthetic body models will potentially pave the way towards objective standardized digital movement disorder diagnosis and building sharable open-source datasets from such processed videos. We provide a hypothesis of this emerging field and describe how clinicians and computer scientists can navigate this new space. Such digital movement capturing methods will be important for both machine learning-based diagnosis and computer vision-aided clinical assessment. It would also supplement face-to-face clinical visits and be used for longitudinal monitoring and remote diagnosis.

关键词： Artificial intelligence computer-assisted diagnosis computer-assisted image processing neural networks (computer) movement disorders Parkinson's disease

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computer-assisted surgery with markerless augmented reality for the surgical removal of mandibular odontogenic cysts: report of two clinical cases

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INTERNATIONAL JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY 2023年第4期53卷 347-350页

作者： Kawakami, H. Suenaga, H. Sakakibara, A. Hoshi, K. Univ Tokyo Hosp Dept Oral Maxillofacial Surg & Orthodont Bunkyo Ku7-3-1 Hongo Tokyo 1138655 Japan

Odontogenic cysts are commonly seen in clinical practice. Surgical enucleation of these cysts becomes challenging when they form adjacent to anatomically important structures. Recently, computer-assisted surgery using computer-aided preoperative simulation and augmented reality (AR) has been applied in oral and maxillofacial surgery. The authors have introduced a new AR system that eliminates the need for markers and uses image recognition of the teeth to overlay the surgical field with preoperative surgical simulation images. This report describes two cases of cystectomy performed using an AR assisted system, one for recurrent odontogenic keratocyst and the other for a dentigerous cyst. The teeth were scanned using a 3D intraoral scanner, while the face was scanned using a computed tomography scanner. A 3D reconstructed image of the mandible was generated, and a dentofacial skeleton model was designed using the intraoral and CT scan data. A camera was used to capture the clinical image and validate the AR. Two cystectomy cases performed using the AR-assisted system and preoperative planning are reported. This new AR system, which eliminates the need for markers and uses image recognition of the teeth to overlay the surgical field with preoperative surgical simulation images, has the potential to provide more accurate and efficient guidance during surgery.

关键词： Augmented reality computer-assisted surgery Mandible Odontogenic cysts computer-assisted image processing computer simulation

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Assessment of volume changes of radial forearm free flaps in head and neck cancer: Long-term results

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ORAL ONCOLOGY 2011年第1期47卷 72-75页

作者： Joo, Young-Hoon Hwang, Se-Hwan Sun, Dong-Il Park, Jun-Ook Cho, Kwang-Jae Kim, Min-Sik Catholic Univ Korea Coll Med Dept Otolaryngol Head & Neck Surg Seoul 137040 South Korea

The goal of this study was to evaluate changes in radial forearm free flap (RFFF) volumes after 5 years of follow-up after ablative tumor surgery in the head and neck. Eighteen patients underwent RFFF reconstruction. Flap volumes were measured by computerized segmentation of CT or MR images. Average postoperative 3 months, and 1, 3, and 5 years flap volumes were 167.4, 129.0, 104.9, and 88.7 cm(3), respectively. Average percentage changes between 3 months and 1-year, 3 months and 3-years, and 3 months and 5-years scans were 20.4, 30.3, and 42.7%, respectively. A significant relation was found between postoperative irradiation and RFFF volume changes from 3 months to 5 years (p = 0.046). Overcorrection with a 40% greater RFFF volume is recommended for the reconstruction of tumor-related defects in the head and neck. (C) 2010 Elsevier Ltd. All rights reserved.

关键词： Surgical flaps Organ size computer-assisted image processing Head and neck neoplasms Radiation

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Optimization of dental CBCT exposures through mAs reduction

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DENTOMAXILLOFACIAL RADIOLOGY 2015年第9期44卷 art. no. 20150108-art. no. 20150108页

作者： Pauwels, R. Seynaeve, L. Henriques, J. C. G. de Oliveira-Santos, C. Souza, P. C. Westphalen, F. H. Rubira-Bullen, I. R. F. Ribeiro-Rotta, R. F. Rockenbach, M. I. B. Haiter-Neto, F. Pittayapat, P. Bosmans, H. Bogaerts, R. Jacobs, R. Chulalongkorn Univ Fac Dent Dept Radiol Bangkok Thailand Univ Leuven Dept Imaging & Pathol OMFS IMPATH Res Grp Biomed Sci GrpOral Imaging Ctr Leuven Belgium Univ Sao Paulo Sch Dent Ribeirao Preto Dent Dept Stomatol Publ Hlth & Forens Dent Sao Paulo Brazil Pontif Catholic Univ Parana Sch Dent Curitiba Parana Brazil Univ Sao Paulo Bauru Sch Dent Dept Stomatol Sao Paulo Brazil Univ Fed Goias Sch Dent Dept Oral Med Goiania Go Brazil Pontif Catholic Univ Rio Grande do Sul Fac Dent Dept Surg Porto Alegre RS Brazil Univ Estadual Campinas Piracicaba Dent Sch Dept Oral Diag Piracicaba Brazil Univ Hosp Leuven Dept Radiol Leuven Belgium Univ Hosp Leuven Dept Expt Radiotherapy Leuven Belgium

Objectives: To investigate the effect of tube current-exposure time (mAs) reduction on clinical and technical image quality for different CBCT scanners, and to determine preliminary minimally acceptable values for the mAs and contrast-to-noise ratio (CNR) in CBCT. Methods: A polymethyl methacrylate (PMMA) phantom and an anthropomorphic skull phantom,, containing a human skeleton embedded in polyurethane, were scanned using four CBCT devices, including seven exposure protocols. For all protocols, the mAs was varied within the selectable range. Using the PMMA phantom, the CNRAIR was measured and corrected for voxel size. Eight axial slices and one coronal slice showing various anatomical landmarks were selected for each CBCT scan of the skull phantom. The slices were presented to six dentomaxillofacial radiologists, providing scores for various anatomical and diagnostic parameters. Results: A hyperbolic relationship was seen between CNRAIR and mAs Similarly, a gradual reduction in clinical image quality was seen at lower mAs values;however, for several protocols, image quality remained acceptable for a moderate or large mAs reduction compared with the standard exposure setting, depending on the clinical application. The relationship between mAs, CNRAIR and observer scores was different for each CBCT device. Minimally acceptable values for mAs were between 9 and 70, depending on the criterion and clinical application. Conclusions: Although noise increased at a lower mAs, clinical image quality often remained acceptable at exposure levels below the manufacturer's recommended setting, for certain patient groups. Currently, it is not possible to determine minimally acceptable values for image quality that are applicable to multiple CBCT models.

关键词： cone-beam computed tomography computer-assisted radiographic image interpretation computer-assisted image processing quality control

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Filtered back projection vs. iterative reconstruction for CBCT: effects on image noise and processing time

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DENTOMAXILLOFACIAL RADIOLOGY 2023年第8期52卷 20230109页

作者： Ramage, Amanda Gutierrez, Bryan Lopez Fischer, Kathleen Sekula, Michael Santaella, Gustavo Machado Scarfe, William Brasil, Danieli Moura de Oliveira-Santos, Christiano Univ Louisville Sch Dent Louisville KY 40292 USA

Objectives: To assess the effect of standard filtered back projection (FBP) and iterative reconstruction (IR) methods on CBCT image noise and processing time (PT), acquired with various acquisition parameters with and without metal artefact reduction (MAR). Methods: CBCT scans using the Midmark EIOS unit of a human mandible embedded in soft tissue equivalent material with and without the presence of an implant at mandibular first molar region were acquired at various acquisition settings (milliamperages [4mA-14mA], FOV [5 x 5, 6 x 8, 9 x 10cm], and resolutions [low, standard, high] and reconstructed using standard FBP and IR, and with and without MAR. The processing time was recorded for each reconstruction. imageJ was used to analyze specific axial images. Radial transaxial fiducial lines were created relative to the implant site. Standard deviations of the gray density values (image noise) were calculated at fixed distances on the fiducial lines on the buccal and lingual aspects at specific axial levels, and mean values for FBP and IR were compared using paired t-tests. Significance was defined as p < 0.05. Results: The overall mean for image noise ( SD) for FBP was 198.65 55.58and 99.84 +/- 16.28 for IR. IR significantly decreased image noise compared to FBP at all acquisition parameters (p < 0.05). Noise reduction among different scanning protocols ranged between 29.7% (5 x 5cm FOV) and 58.1% (5mA). IR increased processing time by an average of 35.1s. Conclusions: IR significantly reduces CBCT image noise compared to standard FBP without substantially increasing processing time.

关键词： MeSH terms: Cone-Beam Computed Tomography Dental Implants Radiographic image Enhancement computer-assisted image processing

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