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  • 1.
    Brodén, Cyrus
    et al.
    Department of Molecular Medicine and Surgery, Karolinska Institutet.
    Olivecrona, Henrik
    Department of Molecular Medicine and Surgery, Karolinska Institutet.
    Maguire Jr., Gerald Q.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Noz, Marilyn E.
    New York University, Department of Radiology.
    Zeleznik, Michael P.
    School of Computing, College of Engineering, University of Utah.
    Sköldenberg, Olof
    Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet.
    Accuracy and Precision of Three-Dimensional Low Dose CT Compared to Standard RSA in Acetabular Cups: An Experimental Study2016In: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, article id 5909741Article in journal (Refereed)
    Abstract [en]

    Background and Purpose. The gold standard for detection of implant wear and migration is currently radiostereometry (RSA). The purpose of this study is to compare a three-dimensional computed tomography technique (3D CT) to standard RSA as an alternative technique for measuring migration of acetabular cups in total hip arthroplasty.

    Materials and Methods. With tantalum beads, we marked one cemented and one uncemented cup and mounted these on a similarly marked pelvic model. A comparison was made between 3D CT and standard RSA for measuring migration. Twelve repeated stereoradiographs and CT scans with double examinations in each position and gradual migration of the implants were made. Precision and accuracy of the 3D CT were calculated.

    Results. The accuracy of the 3D CT ranged between 0.07 and 0.32 mm for translations and 0.21 and 0.82° for rotation. The precision ranged between 0.01 and 0.09 mm for translations and 0.06 and 0.29° for rotations, respectively. For standard RSA, the precision ranged between 0.04 and 0.09 mm for translations and 0.08 and 0.32° for rotations, respectively. There was no significant difference in precision between 3D CT and standard RSA. The effective radiation dose of the 3D CT method, comparable to RSA, was estimated to be 0.33 mSv.

    Interpretation. Low dose 3D CT is a comparable method to standard RSA in an experimental setting.

  • 2.
    Chen, Fengnong
    et al.
    KTH, School of Technology and Health (STH). College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
    Chen, Pulan
    Muhammed, Hamed Hamid
    KTH, School of Technology and Health (STH).
    Zhang, Juan
    Intravoxel Incoherent Motion Diffusion for Identification of Breast Malignant and Benign Tumors Using Chemometrics2017In: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, article id 3845409Article in journal (Refereed)
    Abstract [en]

    Theaim of the paper is to identify the breast malignant and benign lesions using the features of apparent diffusion coefficient (ADC), perfusion fraction f, pseudodiffusion coefficient D*, and true diffusion coefficient D from intravoxel incoherent motion (IVIM). There are 69 malignant cases (including 9 early malignant cases) and 35 benign breast cases who underwent diffusion-weighted MRI at 3.0 T with 8 b-values (0 similar to 1000 s/mm(2)). ADC and IVIM parameters were determined in lesions. The early malignant cases are used as advanced malignant and benign tumors, respectively, so as to assess the effectiveness on the result. A predictive model was constructed using Support VectorMachine Binary Classification (SVMBC, also known Support VectorMachine Discriminant Analysis (SVMDA)) and Partial Least Squares Discriminant Analysis (PLSDA) and compared the difference between them both. The.. value and ADC provide accurate identification of malignant lesions with.. = 300, if early malignant tumor was considered as advanced malignant (cancer). The classification accuracy is 93.5% for cross-validation using SVMBC with ADC and tissue diffusivity only. The sensitivity and specificity are 100% and 87.0%, respectively, r(2) (cv) = 0.8163, and root mean square error of cross-validation (RMSECV) is 0.043. ADC and IVIM provide quantitative measurement of tissue diffusivity for cellularity and are helpful with the method of SVMBC, getting comprehensive and complementary information for differentiation between benign and malignant breast lesions.

  • 3.
    Etehad Tavakol, Mahnaz
    et al.
    Isfahan University of Medical Sciences, Iran.
    Fatemi, Alimohammad
    Isfahan University of Medical Sciences, Iran.
    Karbalaie, Abdolamir
    KTH, School of Technology and Health (STH), Health Systems Engineering.
    Emrani, Zahra
    Isfahan University of Medical Sciences, Iran.
    Erlandsson, Björn-Erik
    KTH, School of Technology and Health (STH), Health Systems Engineering, Systems Safety and Management.
    Nailfold Capillaroscopy in Rheumatic Diseases: Which Parameters Should Be Evaluated?2015In: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, Vol. 2015, article id 974530Article in journal (Refereed)
    Abstract [en]

    Video nailfold capillaroscopy (NFC), considered as an extension of the widefield technique, allows a more accurate measuring andstoring of capillary data and a better defining, analyzing, and quantifying of capillary abnormalities. Capillaroscopic study is oftenperformed on the patients suspected of having microcirculation problems such as Raynaud’s phenomenon as the main indicationfor nailfold capillaroscopy. Capillaroscopic findings based on microcirculation studies can provide useful information in the fieldsof pathophysiology, differential diagnosis, and monitoring therapy. Nailfold capillaroscopy provides a vital assessment in clinicalpractices and research; for example, its reputation in the early diagnosis of systemic sclerosis is well established and it is also usedas a classification criterion in this regard. This review focuses on the manner of performing video nailfold capillaroscopy and on acommon approach for measuring capillary dimensions in fingers and toes.

  • 4.
    Kuang, Qie
    et al.
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Structural Biotechnology. Karolinska Institutet, Sweden.
    Purhonen, Pasi
    Hebert, Hans
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Structural Biotechnology. Karolinska Institutet, Sweden.
    Two-Dimensional Crystallization Procedure, from Protein Expression to Sample Preparation2015In: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, article id 693869Article, review/survey (Refereed)
    Abstract [en]

    Membrane proteins play important roles for living cells. Structural studies of membrane proteins provide deeper understanding of their mechanisms and further aid in drug design. As compared to other methods, electron microscopy is uniquely suitable for analysis of a broad range of specimens, from small proteins to large complexes. Of various electron microscopic methods, electron crystallography is particularly well-suited to study membrane proteins which are reconstituted into two-dimensional crystals in lipid environments. In this review, we discuss the steps and parameters for obtaining large and well-ordered twodimensional crystals. A general description of the principle in each step is provided since this information can also be applied to other biochemical and biophysical methods. The examples are taken from our own studies and published results with related proteins. Our purpose is to give readers a more general idea of electron crystallography and to share our experiences in obtaining suitable crystals for data collection.

  • 5.
    Loskutova, Ksenia
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Medical Imaging.
    Grishenkov, Dmitry
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Medical Imaging.
    Ghorbani, Morteza
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Medical Imaging. Mechatronics Engineering Program, Faculty of Engineering and Natural Science, Sabanci University, Istanbul 34956, Turkey.
    Review on Acoustic Droplet Vaporization in Ultrasound Diagnostics and Therapeutics2019In: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, article id 9480193Article, review/survey (Refereed)
    Abstract [en]

    Acoustic droplet vaporization (ADV) is the physical process in which liquid undergoes phase transition to gas after exposure to a pressure amplitude above a certain threshold. In recent years, new techniques in ultrasound diagnostics and therapeutics have been developed which utilize microformulations with various physical and chemical properties. The purpose of this review is to give the reader a general idea on how ADV can be implemented for the existing biomedical applications of droplet vaporization. In this regard, the recent developments in ultrasound therapy which shed light on the ADV are considered. Modern designs of capsules and nanodroplets (NDs) are shown, and the material choices and their implications for function are discussed. The influence of the physical properties of the induced acoustic field, the surrounding medium, and thermophysical effects on the vaporization are presented. Lastly, current challenges and potential future applications towards the implementation of the therapeutic droplets are discussed.

  • 6.
    Lundblad, Henrik
    et al.
    Karolinska Institutet, Sweden.
    Maguire Jr., Gerald Q.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Karlsson-Thur, Charlotte
    Karolinska Institutet, Sweden.
    Jonsson, Cathrine
    Karolinska University Hospital Solna, Sweden.
    Noz, Marilyn E.
    New York University, USA.
    Zeleznik, Michael P.
    University of Utah, USA.
    Jacobsson, Hans
    Karolinska Institutet, Sweden.
    Weidenhielm, Lars
    Karolinska Institutet, Sweden.
    Using PET/CT Bone Scan Dynamic Data to Evaluate Tibia Remodeling When a Taylor Spatial Frame Is Used: Short and Longer Term Differences2015In: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, Vol. 2015, p. 1-11, article id 574705Article in journal (Refereed)
    Abstract [en]

    Eighteen consecutive patients, treated with a Taylor Spatial Frame for complex tibia conditions, gave their informed consentto undergo Na18F− PET/CT bone scans. We present a Patlak-like analysis utilizing an approximated blood time-activity curveeliminating the need for blood aliquots. Additionally, standardized uptake values (SUV) derived from dynamic acquisitions werecompared to this Patlak-like approach. Spherical volumes of interest (VOIs) were drawn to include broken bone, other (normal)bone, and muscle. The SUV𝑚(𝑡) (𝑚 = max, mean) and a series of slopes were computed as (SUV𝑚(𝑡𝑖) − SUV𝑚(𝑡𝑗))/(𝑡𝑖 − 𝑡𝑗), forpairs of time values 𝑡𝑖 and 𝑡𝑗. A Patlak-like analysis was performed for the same time values by computing ((VOI𝑝(𝑡𝑖)/VOI𝑒(𝑡𝑖)) −(VOI𝑝(𝑡𝑗)/VOI𝑒(𝑡𝑗)))/(𝑡𝑖−𝑡𝑗), where p = broken bone, other bone, andmuscle and e = expected activity in aVOI. Paired comparisonsbetween Patlak-like and SUV𝑚 slopes showed good agreement by both linear regression and correlation coefficient analysis(𝑟 = 84%, 𝑟𝑠 = 78%-SUVmax, 𝑟 = 92%, and 𝑟𝑠 = 91%-SUVmean), suggesting static scans could substitute for dynamic studies.Patlak-like slope differences of 0.1 min−1 or greater between examinations and SUVmax differences of ∼5 usually indicated goodremodeling progress, while negative Patlak-like slope differences of −0.06 min−1 usually indicated poor remodeling progress in thiscohort.

  • 7.
    Otten, Volker
    et al.
    Department of Surgical and Perioperative Sciences (Institutionen för kirurgisk och perioperativ vetenskap), Umeå University, Umeå, Sweden.
    Maguire Jr., Gerald Q.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Noz, Marilyn E.
    New York University, Department of Radiology.
    Zeleznik, Michael P.
    University of Utah.
    Nilsson, Kjell G.
    Department of Surgical and Perioperative Sciences (Institutionen för kirurgisk och perioperativ vetenskap), Umeå University, Umeå, Sweden.
    Olivecrona, Henrik
    Karolinska Institutet, Sweden.
    Are CT Scans a Satisfactory Substitute for the Follow-Up of RSA Migration Studies of Uncemented Cups?: A Comparison of RSA Double Examinations and CT Datasets of 46 Total Hip Arthroplasties2017In: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, Vol. 2017, p. 1-11, article id 3681458Article in journal (Refereed)
    Abstract [en]

    As part of the 14-year follow-up of a prospectively randomized radiostereometry (RSA) study on uncemented cup fixation, two pairs of stereo radiographs and a CT scan of 46 hips were compared. Tantalum beads, inserted during the primary operation, were detected in the CT volume and the stereo radiographs and used to produce datasets of 3D coordinates. The limit of agreement between the combined CT and RSA datasets was calculated in the same way as the precision of the double RSA examination. The precision of RSA corresponding to the 99% confidence interval was 1.36°, 1.36°, and 0.60° for -, -, and -rotation and 0.40, 0.17, and 0.37 mm for -, -, and -translation. The limit of agreement between CT and RSA was 1.51°, 2.17°, and 1.05° for rotation and 0.59, 0.56, and 0.74 mm for translation. The differences between CT and RSA are close to the described normal 99% confidence interval for precision in RSA: 0.3° to 2° for rotation and 0.15 to 0.6 mm for translation. We conclude that measurements using CT and RSA are comparable and that CT can be used for migration studies for longitudinal evaluations of patients with RSA markers.

  • 8.
    Seoane, Fernando
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. Univ Boras, Fac Care Sci Work Life & Social Welfare, Sweden.
    Abtahi, Shirin
    Abtahi, Farhad
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. Karolinska Inst, Dept Clin Sci Intervent & Technol, Sweden.
    Ellegård, Lars
    Johannsson, Gudmundur
    Bosaeus, Ingvar
    Ward, Leigh C
    Mean Expected Error in Prediction of Total Body Water: A True Accuracy Comparison between Bioimpedance Spectroscopy and Single Frequency Regression Equations2015In: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, article id 656323Article in journal (Refereed)
    Abstract [en]

    For several decades electrical bioimpedance (EBI) has been used to assess body fluid distribution and body composition. Despite the development of several different approaches for assessing total body water (TBW), it remains uncertain whether bioimpedance spectroscopic (BIS) approaches are more accurate than single frequency regression equations. The main objective of this study was to answer this question by calculating the expected accuracy of a single measurement for different EBI methods. The results of this study showed that all methods produced similarly high correlation and concordance coefficients, indicating good accuracy as a method. Even the limits of agreement produced from the Bland-Altman analysis indicated that the performance of single frequency, Sun’s prediction equations, at population level was close to the performance of both BIS methods; however, when comparing the Mean Absolute Percentage Error value between the single frequency prediction equations and the BIS methods, a significant difference was obtained, indicating slightly better accuracy for the BIS methods. Despite the higher accuracy of BIS methods over 50 kHz prediction equations at both population and individual level, the magnitude of the improvement was small. Such slight improvement in accuracy of BIS methods is suggested insufficient to warrant their clinical use where the most accurate predictions of TBW are required, for example, when assessing over-fluidic status on dialysis. To reach expected errors below 4-5%, novel and individualized approaches must be developed to improve the accuracy of bioimpedance-based methods for the advent of innovative personalized health monitoring applications.

  • 9.
    Seoane, Fernando
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. University of Borås, Sweden.
    Atefi, seyed Reza
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Jens, Tomner
    Karolinska Hospital.
    Kostulas, Konstantinos
    Karolinska Institute, Department of Neurology.
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Electrical Bioimpedance Spectroscopy on Acute Unilateral Stroke Patients: Initial Observations regarding Differences between Sides2015In: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, Vol. 2015, article id 613247Article in journal (Refereed)
    Abstract [en]

    Purpose. Electrical Bioimpedance Cerebral Monitoring is assessment in real time of health of brain tissue through study of passive dielectric properties of brain. During the last two decades theory and technology have been developed in parallel with animal experiments aiming to confirm feasibility of using bioimpedance-based technology for prompt detection of brain damage. Here, for the first time, we show that electrical bioimpedance measurements for left and right hemispheres are significantly different in acute cases of unilateral stroke within 24 hours from onset. Methods. Electrical BIS measurements have been taken in healthy volunteers and patients suffering from acute stroke within 24 hours of onset. BIS measurements have been obtained using SFB7 bioimpedance spectrometer manufactured by Impedimed ltd. and 4-electrode method. Measurement electrodes, current, and voltage have been placed according to 10–20 EEG system obtaining mutual BIS measurements from 4 different channels situated in pairs symmetrically from the midsagittal line. Obtained BIS data has been analyzed, assessing for symmetries and differences regarding healthy control data.Results. 7 out of 10 patients for Side-2-Side comparisons and 8 out 10 for central/lateral comparison presented values outside the range defined by healthy control group. When combined only 1 of 10 patients exhibited values within the healthy range. Conclusions. If these initial observations are confirmed with more patients, we can foresee emerging of noninvasive monitoring technology for brain damage with the potential to lead to paradigm shift in treatment of brain stroke and traumatic brain damage.

  • 10.
    Zhou, Guang-Quan
    et al.
    Southeast Univ, Sch Biol Sci & Med Engn, Nanjing, Jiangsu, Peoples R China.;Southeast Univ, Natl Demonstrat Ctr Expt Biomed Engn Educ, Nanjing, Jiangsu, Peoples R China..
    Zhang, Yi
    Southeast Univ, Sch Biol Sci & Med Engn, Nanjing, Jiangsu, Peoples R China.;Southeast Univ, Natl Demonstrat Ctr Expt Biomed Engn Educ, Nanjing, Jiangsu, Peoples R China..
    Wang, Ruo-Li
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, BioMEx. Karolinska Inst, Dept Womens & Childrens Hlth, Stockholm, Sweden..
    Zhou, Ping
    Southeast Univ, Sch Biol Sci & Med Engn, Nanjing, Jiangsu, Peoples R China.;Southeast Univ, Natl Demonstrat Ctr Expt Biomed Engn Educ, Nanjing, Jiangsu, Peoples R China..
    Zheng, Yong-Ping
    Hong Kong Polytech Univ, Dept Biomed Engn, Hong Kong, Hong Kong, Peoples R China..
    Tarassova, Olga
    Swedish Sch Sport & Hlth Sci, Stockholm, Sweden..
    Arndt, Anton
    Swedish Sch Sport & Hlth Sci, Stockholm, Sweden.;Karolinska Inst, Dept Clin Intervent & Technol, Stockholm, Sweden..
    Chen, Qiang
    Southeast Univ, Sch Biol Sci & Med Engn, Nanjing, Jiangsu, Peoples R China.;Southeast Univ, Natl Demonstrat Ctr Expt Biomed Engn Educ, Nanjing, Jiangsu, Peoples R China..
    Automatic Myotendinous Junction Tracking in Ultrasound Images with Phase-Based Segmentation2018In: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, article id 3697835Article in journal (Refereed)
    Abstract [en]

    Displacement of the myotendinous junction (MTJ) obtained by ultrasound imaging is crucial to quantify the interactive length changes of muscles and tendons for understanding the mechanics and pathological conditions of the muscle-tendon unit during motion. However, the lack of a reliable automatic measurement method restricts its application in human motion analysis. This paper presents an automated measurement of MTJ displacement using prior knowledge on tendinous tissues and MTJ, precluding the influence of nontendinous components on the estimation of MTJ displacement. It is based on the perception of tendinous features from musculoskeletal ultrasound images using Radon transform and thresholding methods, with information about the symmetric measures obtained from phase congruency. The displacement of MTJ is achieved by tracking manually marked points on tendinous tissues with the Lucas-Kanade optical flow algorithm applied over the segmented MTJ region. The performance of this method was evaluated on ultrasound images of the gastrocnemius obtained from 10 healthy subjects (26.0 +/- 2.9 years of age). Waveform similarity between the manual and automatic measurements was assessed by calculating the overall similarity with the coefficient ofmultiple correlation (CMC). In vivo experiments demonstrated that MTJ tracking with the proposedmethod (CMC = 0.97 +/- 0.02) was more consistent with the manual measurements than existing optical flow tracking methods (CMC = 0.79 +/- 0.11). This study demonstrated that the proposed method was robust to the interference of nontendinous components, resulting in a more reliable measurement of MTJ displacement, whichmay facilitate further research and applications related to the architectural change of muscles and tendons.

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