This review discusses magnetomotive ultrasound, which is an emerging technique that uses superparamagnetic iron oxide nanoparticles as a contrast agent. The key advantage of using nanoparticle-based contrast agents is their ability to reach extravascular targets, whereas commercial contrast agents for ultrasound comprise microbubbles confined to the blood stream. This also extends possibilities for molecular imaging, where the contrast agent is labeled with specific targeting molecules (e.g., antibodies) so that pathologic tissue may be visualized directly. The principle of action is that an external time-varying magnetic field acts to displace the nanoparticles lodged in tissue and thereby their immediate surrounding. This movement is then detected with ultrasound using frequency- or time-domain analysis of echo data. As a contrast agent already approved for magnetic resonance imaging (MRI) by the US Food and Drug Administration, there is a shorter path to clinical translation, although safety studies of magnetomotion are necessary, especially if particle design is altered to affect biodistribution or signal strength. The external modulated magnetic field may be generated by electromagnets, permanent magnets, or a combination of the two. The induced nanoparticle motion may also reveal mechanical material properties of tissue, healthy or diseased, one of several interesting potential future aspects of the technique.

The objective was to provide a clinical setup for photoacoustic imaging (PAI) of the temporal artery in humans and to describe the challenges encountered and methods of overcoming them. The temporal artery was examined in 7 patients with suspect giant cell arteritis (GCA), both in vivo and ex vivo, and the results were compared to that of histology. To adapt PAI to human studies, the transducer was fixed to an adjustable arm to reduce motion artifacts and a stepping motor was developed to enable 3D scanning. Risks associated with the use of lasers, ultrasound, and electrical equipment were evaluated by measuring energy levels, and safety precautions were undertaken to prevent injury to the patients and staff. The PAI spectra obtained clearly delineated the artery wall, both in vivo and ex vivo, although the latter were of higher quality due to the lack of artifacts. The results could be compared to that of histology. The energy levels involved were found to be below limits given in regulatory standards. Eye protectors prevented irradiation of the patient’s eyes, and visual function after the procedure was found not to be affected. The patients reported no discomfort during the investigations. PAI provides images of the temporal artery wall that may be used for the future diagnosis of GCA in humans. The technique could be further refined by addressing the specific problems of motion artefacts and interference from blood and other chromophores. This study paves the way for other clinical applications of PAI.

Blind and low-vision individuals often have severely reduced mobility, affecting their quality of life and associated socioeconomic cost. Despite numerous efforts and great technological progress, the only used primary mobility aids are still white canes and seeing-eye dogs. Furthermore, there is a permeating tendency in the field to ignore knowledge of both mobility and the target group, as well as constantly design new metrics and tests that makes comparisons between solutions markedly more difficult. Method: The Desire of Use model is introduced in an effort to promote a more holistic approach; it should be generalizable for any activity by any user, but is here applied on mobility of blind and low-vision individuals by a proposal and integration of parameters. Results: An embodiment of the model is presented and with it we show why popular mobility metrics of today are insufficient to guide design; what tasks and metrics that should provide better understanding; as well as which fundamental properties determine them and are critical to discuss. Conclusion: Desire of Use has been introduced as a tool and a theoretical framework, and a realization has been proposed. Significance: Desire of Use offers both a structured perspective of pertinent design challenges facing a given solution, as well as a platform from which to compare test results and properties of existing solutions; in for example the field of electronic travel aids it should prove valuable for designing and evaluating new tests and devices.

The number of hip fractures per year worldwide is estimated to reach 6 million by the year 2050. Despite the many advantages of regional blockades when managing pain from such a fracture, these are used to a lesser extent than general analgesia. One reason is that the opportunities for training and obtaining clinical experience in applying nerve blocks can be a challenge in many clinical settings. Ultrasound image guidance based on artificial intelligence may be one way to increase nerve block success rate. We propose an approach using a deep learning semantic segmentation model with U-net architecture to identify the femoral nerve in ultrasound images. The dataset consisted of 1410 ultrasound images that were collected from 48 patients. The images were manually annotated by a clinical professional and a segmentation model was trained. After training the model for 350 epochs, the results were validated with a 10-fold cross-validation. This showed a mean Intersection over Union of 74%, with an interquartile range of 0.66–0.81.

Objective: Blindness and low vision have severe effects on individuals’ quality of life and socioeconomic cost; a main contributor of which is a prevalent and acutely decreased mobility level. To alleviate this, numerous technological solutions have been proposed in the last 70 years; however, none has become widespread. Method: In this paper, we introduce the vision-to-audio, super-scale sensory substitution/supplementation device Audomni; we address the field-encompassing issues of ill-motivated and overabundant test methodologies and metrics; and we utilize our proposed Desire of Use model to evaluate proposed pilot user tests, their results, and Audomni itself. Results: Audomni holds a spatial resolution of 80 x 60 pixels at ~1.2° angular resolution and close to real-time temporal resolution, outdoor-viable technology, and several novel differentiation methods. The tests indicated that Audomni has a low learning curve, and several key mobility subtasks were accomplished; however, the tests would benefit from higher real-life motivation and data collection affordability. Conclusion: Audomni shows promise to be a viable mobility device – with some addressable issues. Employing Desire of Use to design future tests should provide both high real-life motivation and relevance to them. Significance: As far as we know, Audomni features the greatest information conveyance rate in the field, yet seems to offer comprehensible and fairly intuitive sonification; this work is also the first to utilize Desire of Use as a tool to evaluate user tests, a device, and to lay out an overarching project aim.

Numerous electronic travel aids (ETAs) to increase the mobility of blind or low-vision (BLV) individuals have been proposed. However, the lack of established and well-motivated methods, and of recruiting enough BLV test participants, keeps a successful aid illusory. To combat this, a new aid-agnostic questionnaire focused on mobility, the Desire of Use Questionnaire for Mobility of BLV individuals (DoUQ-MoB) and a new portable, large-scale-exploration virtual reality (VR) system, the Parrot-VR, were employed to evaluate the ETA Audomni. Through VR and Audomni, 19 heterogenous BLV participants traversed large-scale urban environments. Their experiences were probed through the DoUQ-MoB, and their movement analyzed. Numerous results are presented, a highlight being that most participants, 76 %, responded that it was very or extremely likely that they would want to use Audomni along with their current aid. Further, Parrot-VR assists in recruiting a satisfying number of diverse BLV participants; and DoUQ-MoB allows to systematically probe their opinions of an aid, and how it relates to others aids, in a considerable quantity of mobility aid aspects. This work illuminates some shortcomings of Audomni, but also shows a majority of BLV participants actually wanting to use a proposed ETA — a result rarely seen so distinctly in the field, and which encourages the continuing efforts of the project. The results are supported by a novel test procedure, which might serve as future inspiration to the field.