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  1. Article ; Online: Multitask Deep Learning Reconstruction and Localization of Lesions in Limited Angle Diffuse Optical Tomography.

    Ben Yedder, Hanene / Cardoen, Ben / Shokoufi, Majid / Golnaraghi, Farid / Hamarneh, Ghassan

    IEEE transactions on medical imaging

    2022  Volume 41, Issue 3, Page(s) 515–530

    Abstract: Diffuse optical tomography (DOT) leverages near-infrared light propagation through tissue to assess its optical properties and identify abnormalities. DOT image reconstruction is an ill-posed problem due to the highly scattered photons in the medium and ... ...

    Abstract Diffuse optical tomography (DOT) leverages near-infrared light propagation through tissue to assess its optical properties and identify abnormalities. DOT image reconstruction is an ill-posed problem due to the highly scattered photons in the medium and the smaller number of measurements compared to the number of unknowns. Limited-angle DOT reduces probe complexity at the cost of increased reconstruction complexity. Reconstructions are thus commonly marred by artifacts and, as a result, it is difficult to obtain an accurate reconstruction of target objects, e.g., malignant lesions. Reconstruction does not always ensure good localization of small lesions. Furthermore, conventional optimization-based reconstruction methods are computationally expensive, rendering them too slow for real-time imaging applications. Our goal is to develop a fast and accurate image reconstruction method using deep learning, where multitask learning ensures accurate lesion localization in addition to improved reconstruction. We apply spatial-wise attention and a distance transform based loss function in a novel multitask learning formulation to improve localization and reconstruction compared to single-task optimized methods. Given the scarcity of real-world sensor-image pairs required for training supervised deep learning models, we leverage physics-based simulation to generate synthetic datasets and use a transfer learning module to align the sensor domain distribution between in silico and real-world data, while taking advantage of cross-domain learning. Applying our method, we find that we can reconstruct and localize lesions faithfully while allowing real-time reconstruction. We also demonstrate that the present algorithm can reconstruct multiple cancer lesions. The results demonstrate that multitask learning provides sharper and more accurate reconstruction.
    MeSH term(s) Algorithms ; Artifacts ; Deep Learning ; Image Processing, Computer-Assisted/methods ; Tomography, Optical/methods
    Language English
    Publishing date 2022-03-02
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 622531-7
    ISSN 1558-254X ; 0278-0062
    ISSN (online) 1558-254X
    ISSN 0278-0062
    DOI 10.1109/TMI.2021.3117276
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Translation of a portable diffuse optical breast scanner probe for clinical application: a preliminary study.

    Shokoufi, Majid / Haeri, Zahra / Lim, Zhi Yih / Ramaseshan, Ramani / Golnaraghi, Farid

    Biomedical physics & engineering express

    2020  Volume 6, Issue 1, Page(s) 15037

    Abstract: Most breast cancer lesions absorb higher levels of near-infrared (NIR) radiation compared to healthy breast tissue due to its increased vascularity. Oxy-hemoglobin ( ... ...

    Abstract Most breast cancer lesions absorb higher levels of near-infrared (NIR) radiation compared to healthy breast tissue due to its increased vascularity. Oxy-hemoglobin (HbO
    MeSH term(s) Aged ; Aged, 80 and over ; Algorithms ; Breast Neoplasms/diagnosis ; Cross-Sectional Studies ; Female ; Hemoglobins/analysis ; Humans ; Middle Aged ; Optics and Photonics/methods ; Spectroscopy, Near-Infrared/methods
    Chemical Substances Hemoglobins
    Language English
    Publishing date 2020-02-03
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 2057-1976
    ISSN (online) 2057-1976
    DOI 10.1088/2057-1976/ab6e19
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Compression-dependency of soft tissue bioimpedance for in-vivo and in-vitro tissue testing

    Moqadam Sepideh M. / Grewal Parvind / Shokoufi Majid / Golnaraghi Farid

    Journal of Electrical Bioimpedance, Vol 6, Iss 1, Pp 22-

    2015  Volume 32

    Abstract: The present study determines the effect of compression over bioimpedance of healthy soft tissue (in-vitro and in-vivo). Electrical impedance spectroscopy (EIS) is a promising tissue characterization and tumor detection technique that uses tissue ... ...

    Abstract The present study determines the effect of compression over bioimpedance of healthy soft tissue (in-vitro and in-vivo). Electrical impedance spectroscopy (EIS) is a promising tissue characterization and tumor detection technique that uses tissue impedance or admittance to characterize tissue and identify tissue properties as well as cell structure. Variation in EIS measurements while applying pressure suggests that compression tends to affect soft tissue bioimpedance. Moreover, the displacements in tissue caused by applied compression may provide useful information about the structure and state of the tissue. Thus combining the changes to the electrical properties of tissue resulted by applied compression, with the changes in tissue displacements caused by applied compression, and consequently measuring the effect that electrical and mechanical properties have on each other, can be useful to identify tissue structure. In this study, multifrequency bioimpedance measurements were performed on in-vitro and in-vivo soft tissue at different pressure levels. Increasing compression on the in-vitro tissue results in an increase in both extracellular resistance and membrane capacitance while it causes a reduction in the intracellular resistance. However, as the compression over the in-vivo samples increases, the intracellular and extracellular resistance increase and the membrane capacitance decreases. The in-vivo measurements on human body are also tested on contra-lateral tissue sites and similar tissue impedance variation trends are observed in the contra-lateral sites of human body. The evidence from these tests suggests the possibility of using this EIS-Pressure combined measurement method to improve tumor detection in soft tissue. Based upon the observations, the authors envision developing an advanced model based upon the Cole model, which is dependent on tissue displacements.
    Keywords bioimpedance ; soft tissue ; compression ; in-vivo ; in-vitro ; electrical impedance spectroscopy ; Medicine (General) ; R5-920
    Subject code 571
    Language English
    Publishing date 2015-12-01T00:00:00Z
    Publisher Sciendo
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Electrical characterization of bolus material as phantom for use in electrical impedance and computed tomography fusion imaging

    Grewal Parvind K / Shokoufi Majid / Liu Jeff / Kalpagam Krishnan / Kohli Kirpal S

    Journal of Electrical Bioimpedance, Vol 5, Iss 1, Pp 34-

    2014  Volume 39

    Abstract: Phantoms are widely used in medical imaging to predict image quality prior to clinical imaging. This paper discusses the possible use of bolus material, as a conductivity phantom, for validation and interpretation of electrical impedance tomography (EIT) ...

    Abstract Phantoms are widely used in medical imaging to predict image quality prior to clinical imaging. This paper discusses the possible use of bolus material, as a conductivity phantom, for validation and interpretation of electrical impedance tomography (EIT) images. Bolus is commonly used in radiation therapy to mimic tissue. When irradiated, it has radiological characteristics similar to tissue. With increased research interest in CT/EIT fusion imaging there is a need to find a material which has both the absorption coefficient and electrical conductivity similar to biological tissues. In the present study the electrical properties, specifically resistivity, of various commercially available bolus materials were characterized by comparing their frequency response with that of in-vivo connective adipose tissue. It was determined that the resistivity of Gelatin Bolus is similar to in-vivo tissue in the frequency range 10 kHz to 1MHz and therefore has potential to be used in EIT/CT fusion imaging studies.
    Keywords bolus ; electrical impedance tomography ; ct ; tissue electrical properties ; Medicine (General) ; R5-920
    Language English
    Publishing date 2014-04-01T00:00:00Z
    Publisher Sciendo
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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