Magnetic resonance elastography with guided pressure waves

Magnetic resonance elastography aims to non-invasively and remotely characterize the mechanical properties of living tissues. To quantitatively and regionally map the shear viscoelastic moduli in vivo, the technique must achieve proper mechanical excitation throughout the targeted tissues. Although it is straightforward, ante manibus, in close organs such as the liver or the breast, which practitioners clinically palpate already, it is somewhat fortunately highly challenging to trick the natural protective barriers of remote organs such as the brain. So far, mechanical waves have been induced in the latter by shaking the surrounding cranial bones. Here, the skull was circumvented by guiding pressure waves inside the subject's buccal cavity so mechanical waves could propagate from within through the brainstem up to the brain. Repeatable, reproducible and robust displacement fields were recorded in phantoms and in vivo by magnetic resonance elastography with guided pressure waves such that quantitative mechanical outcomes were extracted in the human brain.     

Education in people with venous leg ulcers based on a brochure about compression therapy: A quasi‐randomised controlled trial

Brochures are a useful supplement to patient education. There is increasing evidence that they are an effective medium to support patient satisfaction, adherence, and empowerment. This study aims to produce reliable data on how much patients with venous leg ulcer (VLU) may profit from a brochure that focuses on VLU and on measures and aims of the related compression therapy. The evaluation took part from October 2018 until March 2019 and included 136 patients with VLU and related compression therapy. They were randomly sorted into a case group and a control group of 68 patients each. The case group received a brochure about venous disease and compression therapy and filled in a questionnaire after reading. The questions ranged from basic knowledge about VLU and compression therapy to aspects of self‐care. The control group answered the same questions without previous reading of the brochure. The results show that in almost every aspect, the patients in the case group were better informed about their diseases, the compression therapy, and how they may support the measures adequately. This study suggests that patients with VLU may profit from a brochure that explains their disease and the related compression therapy. Better knowledge and understanding may strengthen their empowerment and adherence.     

Standard Needle Magnetization for Ultrasound Needle Guidance: First Clinical Experiences in Fine‐Needle Aspiration Cytology of Thyroid Nodules

Fine‐needle aspiration cytology using a novel ultrasound needle guidance system on the basis of standard needle magnetization was consecutively performed in 30 (15 in‐plane and 15 out‐of‐plane) suspicious thyroid nodules. Nondedicated, commercially available needles were used. The technical effectiveness and safety of the system were satisfying; system failures were observed in 2 cases. The needle tip could be (at least occasionally) visualized inside the thyroid nodule in 96%, and the subjective procedure ratings were excellent in 57%. The out‐of‐plane technique was significantly superior in both respects (P = .021 and .027, respectively). Standard needle magnetization ultrasound needle guidance was easy to apply and cost‐effective and has the potential to improve fine‐needle aspiration cytology performance.     

Live-imaging of revertant and therapeutically restored dystrophin in the DmdEGFP-mdx mouse model for Duchenne muscular dystrophy

Background

Dmd^mdx, harbouring the c.2983C>T nonsense mutation in Dmd exon 23, is a mouse model for Duchenne muscular dystrophy (DMD), frequently used to test therapies aimed at dystrophin restoration. Current translational research is methodologically hampered by the lack of a reporter mouse model, which would allow direct visualization of dystrophin expression as well as longitudinal in vivo studies.

Methods

We generated a Dmd^EGFP-mdx reporter allele carrying in cis the mdx-23 mutation and a C-terminal EGFP-tag. This mouse model allows direct visualization of spontaneously and therapeutically restored dystrophin-EGFP fusion protein either after natural fibre reversion, or for example, after splice modulation using tricyclo-DNA to skip Dmd exon 23, or after gene editing using AAV-encoded CRISPR/Cas9 for Dmd exon 23 excision.

Results

Intravital microscopy in anaesthetized mice allowed live-imaging of sarcolemmal dystrophin-EGFP fusion protein of revertant fibres as well as following therapeutic restoration. Dystrophin-EGFP-fluorescence persisted ex vivo, allowing live-imaging of revertant and therapeutically restored dystrophin in isolated fibres ex vivo. Expression of the shorter dystrophin-EGFP isoforms Dp71 in the brain, Dp260 in the retina, and Dp116 in the peripheral nerve remained unabated by the mdx-23 mutation.

Conclusion

Intravital imaging of Dmd^EGFP-mdx muscle permits novel experimental approaches such as the study of revertant and therapeutically restored dystrophin in vivo and ex vivo.