| 1. |
- Ge, Chenjie, 1991, et al.
(author)
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Enlarged Training Dataset by Pairwise GANs for Molecular-Based Brain Tumor Classification
- 2020
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In: IEEE Access. - 2169-3536 .- 2169-3536. ; 8:1, s. 22560-22570
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Journal article (peer-reviewed)abstract
- This paper addresses issues of brain tumor subtype classification using Magnetic Resonance Images (MRIs) from different scanner modalities like T1 weighted, T1 weighted with contrast-enhanced, T2 weighted and FLAIR images. Currently most available glioma datasets are relatively moderate in size, and often accompanied with incomplete MRIs in different modalities. To tackle the commonly encountered problems of insufficiently large brain tumor datasets and incomplete modality of image for deep learning, we propose to add augmented brain MR images to enlarge the training dataset by employing a pairwise Generative Adversarial Network (GAN) model. The pairwise GAN is able to generate synthetic MRIs across different modalities. To achieve the patient-level diagnostic result, we propose a post-processing strategy to combine the slice-level glioma subtype classification results by majority voting. A two-stage course-to-fine training strategy is proposed to learn the glioma feature using GAN-augmented MRIs followed by real MRIs. To evaluate the effectiveness of the proposed scheme, experiments have been conducted on a brain tumor dataset for classifying glioma molecular subtypes: isocitrate dehydrogenase 1 (IDH1) mutation and IDH1 wild-type. Our results on the dataset have shown good performance (with test accuracy 88.82%). Comparisons with several state-of-the-art methods are also included.
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| 2. |
- Robinson, Yohan, 1977, et al.
(author)
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AI och framtidens försvarsmedicin
- 2020
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Reports (other academic/artistic)abstract
- Medicinskt legitimerad personal är, och kommer med stor sannolikhet fortsattatt vara, en knapp resurs inom Försvarsmaktens sjukvårdsorganisation. I denna rapport ges en översikt över pågående och planerade ansatser baserade påartificiell intelligens (AI) inom akutsjukvård med särskild tonvikt på omhändertagandet av traumapatienter, där lösningarna skulle kunna bidra till att Försvarsmakten kan bibehålla sin sjukvårdskapacitet i kritiska lägen. Rapporten är ett resultat av samarbetet mellan FM, FOI, FMV, FHS och KI, och vänder sig i första hand till Försvarsmaktens strategiska ledning.Användningen av AI-teknik i framtida beslutsstöd kan skapa nya möjligheter till avlastning av personal och resurseffektivisering. Tekniken ger möjligheter att i realtid samla in, bearbeta och analysera stora mängder blandadinformation om förbands hälsoläge och fysiska stridsvärde. Bedömning av skadade kan t.ex. göras av triagedrönare och den efterföljande evakueringen kanunderlättas av intelligenta autonoma plattformar. Införandet av AI-system ställer dock vårdgivaren inför svåra etiska och medikolegala överväganden.Försvarsmedicin har en central roll i Försvarsmaktens krigföringsförmåga och för samhällets uthållighet. För att nyttja hela AI-teknikens framfart till Försvarsmaktens nytta måste dess innebörd och konsekvens för försvarsmedicinen förstås. Därför rekommenderar denna studie att Försvarsmaktens framtida satsningar inom AI och autonomi inkluderar den försvarsmedicinska teknikutveckling som är beskriven i denna rapport.
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| 3. |
- Lendaro, Eva, 1989
(author)
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On the use of Phantom Motor Execution for the treatment of Phantom Limb Pain
- 2020
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Licentiate thesis (other academic/artistic)abstract
- Phantom limb pain (PLP) is a common complaint among amputees and despite having been studied for centuries, it remains a mysterious object of debate among researcher. To date, a vast number of ways to treat PLP has been proposed in the literature, however none of them has proven to be universally effective, thus creating uncertainty on how to operate clinically. The uncertainty is largely attributable to the scarcity of well conducted randomized controlled trials (RCTs) to prove the efficacy of PLP treatments. Phantom Motor Execution (PME) -exertion of voluntary phantom limb movements – aims at restoring the control over the phantom limb and the exercise of such control has been hypothesized to reverse neural changes implicated in PLP. Preliminary evidence supporting this hypothesis has been provided by clinical investigations on upper limb amputees. The main purpose of this Licentiate thesis was to enable a RCT on the use of PME for the treatment of PLP in order to provide robust and unbiased evidence for clinical practice. However, the implementation and kick-off of this clinical investigation required to complete few preparatory steps. For example, most amputees and PLP patients have lower limb amputation, thus PME needed to be adapted and validated for this population. Further, the RCT protocol needed to be carefully planned and made openly accessible, as per guidelines for conducting and publishing clinical RCT. Finally, a secondary aim of this thesis emerged with the need of providing long term relief from PLP to patient. Preliminary evidence seemed to indicate that in order to maintain pain relief, periodic rehearsal of the phantom motor skills acquired through PME is necessary. This raised the question of whether it is beneficial and possible to translate the technology from clinic to home use, question that was explored employing both quantitative and qualitative methods from engineering, medical anthropology, and user interface design. The work conducted within this thesis resulted in the extension of PME to lower limb patients by proposal and validation of a new and more user-friendly recording configuration to record EMG signals. The use of PME was then shown to be efficacious in relieving PLP with a case study on a patient. The protocol for the RCT was then designed and published. These two first steps permitted the establishment of the RCT, which is currently ongoing and expected to close in March 2021. With regard to the secondary aim of this thesis, the work conducted enabled PME to be used by the patients in the comfort of their home, while it also allowed investigate the benefits and challenges generally faced (not only by PME) in the transition from the clinic to home and its effects on treatment adherence. The work conducted is presented in the three appended publications. Future work includes the presentation of the results of the RCT. Further, having a way to modulate PLP is an incredibly useful tool to study the neural basis of PLP. By capitalizing on this tool, we are currently conducting brain imaging studies using fMRI and electroencephalography that are the main focus of the work that lies ahead.
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| 4. |
- Jacobson, Lena, et al.
(author)
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Retinal ganglion cell topography predicts visual field function in spastic cerebral palsy
- 2020
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In: Developmental Medicine and Child Neurology. - : Wiley. - 0012-1622 .- 1469-8749. ; 62:9, s. 1100-1106
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Journal article (peer-reviewed)abstract
- The aim of this study was to evaluate the use of optical coherence tomography (OCT) to identify and assess visual field defects caused by primary damage to the optic radiation in individuals with spastic cerebral palsy (CP). Ten individuals with spastic CP (six females, four males, with a median age of 21 years [range 17–38y]) had their brain lesions documented with conventional magnetic resonance imaging (MRI) and diffusion-weighted MRI fibre tractography. Their macular ganglion cell layer (GCL) and inner plexiform layer (IPL) were examined with OCT and their visual fields were plotted. All participants had good visual acuity and were able to cooperate with the MRI and OCT examinations, as well as undergoing reliable perimetry. We found focal thinning of the GCL+IPL and corresponding homonymous visual field defects in individuals with brain damage affecting the optic radiation. We used GCL+IPL sector asymmetry as a sensitive OCT parameter to identify focal visual field defects. We observed no such sector asymmetry in GCL+IPL, or focal visual field defects, in individuals with normal MRI optic radiation imaging. Lesions affecting the optic radiation cause retrograde trans-synaptic degeneration of retinal ganglion cells. OCT examination of the GCL in the macula identified corresponding focal damage to the optic radiation in individuals with spastic CP and can be used to predict focal visual field defects. What this paper adds: Spastic cerebral palsy (CP) may be associated with damage to the optic radiation. Damage to the optic radiation causes retrograde trans-synaptic degeneration (RTSD). RTSD can be mapped using optical coherence tomography. Ganglion cell topography can predict visual field defects in individuals with spastic CP.
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| 5. |
- Polymeri, Erini, et al.
(author)
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Deep learning-based quantification of PET/CT prostate gland uptake : association with overall survival
- 2020
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In: Clinical Physiology and Functional Imaging. - Chichester : Blackwell Publishing. - 1475-0961 .- 1475-097X. ; 40:2, s. 106-113
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Journal article (peer-reviewed)abstract
- Aim: To validate a deep-learning (DL) algorithm for automated quantification of prostate cancer on positron emission tomography/computed tomography (PET/CT) and explore the potential of PET/CT measurements as prognostic biomarkers. Material and methods: Training of the DL-algorithm regarding prostate volume was performed on manually segmented CT images in 100 patients. Validation of the DL-algorithm was carried out in 45 patients with biopsy-proven hormone-naïve prostate cancer. The automated measurements of prostate volume were compared with manual measurements made independently by two observers. PET/CT measurements of tumour burden based on volume and SUV of abnormal voxels were calculated automatically. Voxels in the co-registered 18F-choline PET images above a standardized uptake value (SUV) of 2·65, and corresponding to the prostate as defined by the automated segmentation in the CT images, were defined as abnormal. Validation of abnormal voxels was performed by manual segmentation of radiotracer uptake. Agreement between algorithm and observers regarding prostate volume was analysed by Sørensen-Dice index (SDI). Associations between automatically based PET/CT biomarkers and age, prostate-specific antigen (PSA), Gleason score as well as overall survival were evaluated by a univariate Cox regression model. Results: The SDI between the automated and the manual volume segmentations was 0·78 and 0·79, respectively. Automated PET/CT measures reflecting total lesion uptake and the relation between volume of abnormal voxels and total prostate volume were significantly associated with overall survival (P = 0·02), whereas age, PSA, and Gleason score were not. Conclusion: Automated PET/CT biomarkers showed good agreement to manual measurements and were significantly associated with overall survival. © 2019 The Authors. Clinical Physiology and Functional Imaging published by John Wiley & Sons Ltd on behalf of Scandinavian Society of Clinical Physiology and Nuclear Medicine
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| 6. |
- Ortiz Catalan, Max Jair, 1982, et al.
(author)
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Self-Contained Neuromusculoskeletal Arm Prostheses
- 2020
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In: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 382:18, s. 1732-1738
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Journal article (peer-reviewed)abstract
- After transhumeral amputation, four patients had implantation of a self-contained, osseointegrated prosthesis with a neuromusculoskeletal interface that allowed intuitive control of the prosthetic hand and arm over 3 to 7 years. A video shows use of the prostheses in daily life. We report the use of a bone-anchored, self-contained robotic arm with both sensory and motor components over 3 to 7 years in four patients after transhumeral amputation. The implant allowed for bidirectional communication between a prosthetic hand and electrodes implanted in the nerves and muscles of the upper arm and was anchored to the humerus through osseointegration, the process in which bone cells attach to an artificial surface without formation of fibrous tissue. Use of the device did not require formal training and depended on the intuitive intent of the user to activate movement and sensory feedback from the prosthesis. Daily use resulted in increasing sensory acuity and effectiveness in work and other activities of daily life. (Funded by the Promobilia Foundation and others.)
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| 7. |
- Stigson, Helena, 1979, et al.
(author)
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Health status and quality of life among road users with permanent medical impairment several years after the crash
- 2020
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In: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 21:S1, s. S43-S48
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Journal article (peer-reviewed)abstract
- Objective Improvements in road infrastructure and vehicle safety have been achieved in many countries during the last decades. As the number of fatalities have dropped, the consequences of non-fatal injuries have been brought into focus. Therefore, the objective was to investigate self-reported health status and health-related quality of life several years after the crash for road-users that sustained injuries resulting in permanent medical impairment (PMI). Methods A self-administered questionnaire using instruments to measure if health, health-related quality of life and physical activity had been affected by the crash, were used. The injured road-users were identified from insurance policy holders of the Folksam Insurance Group. The response rate was 29%, a total of 2078 responses were received from the 7174 road-users with PMI that received the questionnaire. Results In total 85% were still suffering from the injuries several years after the crash (8-18 year after the crash). Furthermore, road-users with injuries to the spine were having highest pain intensity. Older road-users had poorer self-reported health status than younger road-users. Although, younger road-users had the greatest change in physical activity when comparing before and after the crash. Before the crash in total 63% were physically active while only 34% after the crash. The higher the PMI the higher it affected health several years after the crash. Conclusions The Swedish definition of serious injury, an injury leading to PMI, was found to correlate with self-reported health loss; 85% of the injured road-users reported that they still had remaining symptoms several years after the accident. The injured body region leading to PMI after an accident can vary from the body regions reported to cause long-term health loss. It was found that the higher the degree of PMI the higher the health loss. Sustaining a PMI regardless severity and injured body region has the same effects on general health for men and women. Sustaining a PMI will both lower the health-related quality of life and physical activity after the crash compared to before.
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| 8. |
- Ge, Chenjie, 1991, et al.
(author)
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Deep semi-supervised learning for brain tumor classification
- 2020
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In: BMC Medical Imaging. - : Springer Science and Business Media LLC. - 1471-2342. ; 20:1
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Journal article (peer-reviewed)abstract
- Background: This paper addresses issues of brain tumor, glioma, classification from four modalities of Magnetic Resonance Image (MRI) scans (i.e., T1 weighted MRI, T1 weighted MRI with contrast-enhanced, T2 weighted MRI and FLAIR). Currently, many available glioma datasets often contain some unlabeled brain scans, and many datasets are moderate in size. Methods: We propose to exploit deep semi-supervised learning to make full use of the unlabeled data. Deep CNN features were incorporated into a new graph-based semi-supervised learning framework for learning the labels of the unlabeled data, where a new 3D-2D consistent constraint is added to make consistent classifications for the 2D slices from the same 3D brain scan. A deep-learning classifier is then trained to classify different glioma types using both labeled and unlabeled data with estimated labels. To alleviate the overfitting caused by moderate-size datasets, synthetic MRIs generated by Generative Adversarial Networks (GANs) are added in the training of CNNs. Results: The proposed scheme has been tested on two glioma datasets, TCGA dataset for IDH-mutation prediction (molecular-based glioma subtype classification) and MICCAI dataset for glioma grading. Our results have shown good performance (with test accuracies 86.53% on TCGA dataset and 90.70% on MICCAI dataset). Conclusions: The proposed scheme is effective for glioma IDH-mutation prediction and glioma grading, and its performance is comparable to the state-of-the-art.
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| 9. |
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| 10. |
- Mastinu, Enzo, 1987, et al.
(author)
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Neural feedback strategies to improve grasping coordination in neuromusculoskeletal prostheses
- 2020
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 10:1
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Journal article (peer-reviewed)abstract
- Conventional prosthetic arms suffer from poor controllability and lack of sensory feedback. Owing to the absence of tactile sensory information, prosthetic users must rely on incidental visual and auditory cues. In this study, we investigated the effect of providing tactile perception on motor coordination during routine grasping and grasping under uncertainty. Three transhumeral amputees were implanted with an osseointegrated percutaneous implant system for direct skeletal attachment and bidirectional communication with implanted neuromuscular electrodes. This neuromusculoskeletal prosthesis is a novel concept of artificial limb replacement that allows to extract control signals from electrodes implanted on viable muscle tissue, and to stimulate severed afferent nerve fibers to provide somatosensory feedback. Subjects received tactile feedback using three biologically inspired stimulation paradigms while performing a pick and lift test. The grasped object was instrumented to record grasping and lifting forces and its weight was either constant or unexpectedly changed in between trials. The results were also compared to the no-feedback control condition. Our findings confirm, in line with the neuroscientific literature, that somatosensory feedback is necessary for motor coordination during grasping. Our results also indicate that feedback is more relevant under uncertainty, and its effectiveness can be influenced by the selected neuromodulation paradigm and arguably also the prior experience of the prosthesis user.
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