Human brain tissue identification using coherent anti-Stokes Raman scattering spectroscopy and diffuse reflectance spectroscopy for deep brain stimulation surgery.

Significance: We assess the feasibility of using diffuse reflectance spectroscopy (DRS) and coherent anti-Stokes Raman scattering spectroscopy (CARS) as optical tools for human brain tissue identification during deep brain stimulation (DBS) lead insertion, thereby providing a promising avenue for additional real-time neurosurgical guidance. Aim: We developed a system that can acquire CARS and DRS spectra during the DBS surgery procedure to identify the tissue composition along the lead trajectory. Approach: DRS and CARS spectra were acquired using a custom-built optical probe integrated in a commercial DBS lead. The lead was inserted to target three specific regions in each of the brain hemispheres of a human cadaver. Spectra were acquired during the lead insertion at constant position increments. Spectra were analyzed to classify each spectrum as being from white matter (WM) or gray matter (GM). The results were compared with tissue classification performed on histological brain sections. Results: DRS and CARS spectra obtained using the optical probe can identify WM and GM during DBS lead insertion. The tissue composition along the trajectory toward a specific target is unique and can be differentiated by the optical probe. Moreover, the results obtained with principal component analysis suggest that DRS might be able to detect the presence of blood due to the strong optical absorption of hemoglobin. Conclusions: It is possible to use optical measurements from the DBS lead during surgery to identify WM and GM and possibly the presence of blood in human brain tissue. The proposed optical tool could inform the surgeon during the lead placement if the lead has reached the target as planned. Our tool could eventually replace microelectrode recordings, which would streamline the process and reduce surgery time. Further developments are required to fully integrate these tools into standard clinical procedures.

Millimetric scale two-photon Bessel-Gauss beam light sheet microscopy with three-axis isotropic resolution using an axicon lens.

Significance: Typical light sheet microscopes suffer from artifacts related to the geometry of the light sheet. One main inconvenience is the non-uniform thickness of the light sheet obtained with a Gaussian laser beam. Aim: We developed a two-photon light sheet microscope that takes advantage of a thin and long Bessel-Gauss beam illumination to increase the sheet extent without compromising the resolution. Approach: We use an axicon lens placed directly at the output of an amplified femtosecond laser to produce a long Bessel-Gauss beam on the sample. We studied the dopaminergic system and its projections in a whole cleared mouse brain. Results: Our light sheet microscope allows an isotropic resolution of 2.4 µm in all three axes of the scanned volume while keeping a millimetric-sized field of view, and a fast acquisition rate of up to 34 mm2/s. With slight modifications to the optical setup, the sheet extent can be increased to 6 mm. Conclusion: The proposed system's sheet extent and resolution surpass currently available systems, enabling the fast imaging of large specimens.

How satisfied are hospital systems with their ownership of retail clinics?

Retail clinics--while innovative--can no longer be considered a new model of healthcare delivery, as an increasing number of hospitals and health systems now own them. The purpose of this article is to explore the extent to which hospital systems are satisfied with their ownership of retail clinics. In terms of operational challenges, respondents to our survey, administered to representatives from 19 health systems, were relatively satisfied with clinic staffing and their relationship with the retailers regarding lease terms, store locations, and shopper demographics. They expressed mostly neutral levels of satisfaction with regulations and laws related to retail clinics and low satisfaction with insurance reimbursement and clinics' seasonal patterns. The two areas that received the lowest respondent satisfaction ratings were patient volume and response to marketing initiatives. When asked to share their perceptions of their organization's satisfaction with various strategic aspects of retail clinic ownership, respondents revealed that the clinics were achieving several important strategic goals, such as improved access, increased referrals, defense against competitors, and increased brand exposure. They indicated overall dissatisfaction with profitability and cost-reduction outcomes. We conclude that serious operational challenges and strategic threats must be overcome if retail clinics are to be a successful service line for hospitals and health systems.