Remote photonic sensing of action potential in mammalian nerve cells via histogram-based analysis of temporal spatial acoustic vibrations.

Label free and remote action potential detection in neurons can be of great importance in the neuroscience research field. This paper presents a novel label free imaging modality based on the detection of temporal vibrations of speckle patterns illuminating the sample. We demonstrated the feasibility of detecting action potentials originating from spontaneous and stimulated activity in cortical cell culture. The spatiotemporal vibrations of isolated cortical cells were extracted by illuminating the culture with a laser beam while the vibrations of the random back scattered secondary speckle patterns are captured by a camera. The postulated action potentials were estimated following correlation-based analysis on the captured vibrations, where the variance deviation of the signal from a Gaussian distribution is directly associated with the action potential events. The technique was validated in a series of experiments in which the optical signals were acquired concurrently with microelectrode array (MEA) recordings. Our results demonstrate the ability of detecting action potential events in mammalian cells remotely via extraction of acoustic vibrations.

Is routine portable pelvic X-ray in stable multiple trauma patients always justified in a high technology era?

INTRODUCTION: According to the Advanced Trauma Life Support, portable pelvis radiography (PXR) is mandatory in multiple trauma patients, and is performed following initial clinical evaluation. The purpose of an early PXR is to identify pelvic fractures that may have haemodynamic consequences. Today, ultrafast multi-detector CT scanners (MDCT) are readily available and widely used in the evaluation of stable trauma patients. The objective of this study was to determine the impact of PXR in stable blunt multiple trauma patients, who required CT scan for full evaluation of the abdomen and pelvis. METHODS: A retrospective review of all stable blunt trauma patients, suffering from pelvic fractures was performed from January 2001 until December 2004 at two high volume Trauma Centres. Patients' demographics and Injury Severity Scores (ISS) were abstracted from our trauma registry. Two certified radiologists and two certified orthopaedic surgeons retrospectively evaluated and compared PXR films and CT angiographies (CTA) of the abdomen and pelvis. We recorded each case when the management policy was altered due to the results of imaging and compared the clinical impact of both modalities. RESULTS: One hundred and twenty-nine stable blunt multiple trauma patients with pelvic fractures underwent CTA of the abdomen and pelvis during their initial evaluation. Mean ISS was 16.5. Average Glasgow Coma Scale on arrival was 13.2 (range 3-15). Compared to CTA, sensitivity and specificity of the PXR was 64.4 and 90.0%, respectively. CTA diagnosed 35.6% more pelvic fractures than PXR (p<0.05). No changes in the therapeutic policy were observed following PXR results. In 19 (14.7%) patients, CTA findings led to pelvic angiography. CONCLUSIONS: PXR in stable blunt multiple trauma patients did not change the therapeutic policy in our patients. CTA of the abdomen and pelvis is the imaging modality of choice in blunt multiple trauma, regardless of the findings of PXR. Benefit of routine PXR is questionable in hospitals where MDCT is available. Based on our results, we suggest re-evaluating the current practice of routine mandatory portable pelvis radiography.