Robotically applied hemostatic clamping for care-under-fire: harnessing bomb robots for hemorrhage control.

BACKGROUND: Early hemorrhage control after interpersonal violence is the most urgent requirement to preserve life and is now recognized as a responsibility of law enforcement. Although earlier entry of first responders is advocated, many shooting scenes remain unsafe for humans, necessitating first responses conducted by robots. Thus, robotic hemorrhage control warrants study as a care-under-fire treatment option. METHODS: Two bomb disposal robots (Wolverine and Dragon Runner) were retrofitted with hemostatic wound clamps. The robots' ability to apply a wound clamp to a simulated extremity exsanguination while controlled by 4 experienced operators was tested. The operators were randomly assigned to perform 10 trials using 1 robot each. A third surveillance robot (Stair Climber) provided further visualization for the operators. We assessed the success rate of the application of the wound clamp to the simulated wound, the time to application of the wound clamp and the amount of fluid loss. We also assessed the operators' efforts to apply the wound clamp after an initial attempt was unsuccessful or after the wound clamp was dropped. RESULTS: Remote robotic application of a wound clamp was demonstrated to be feasible, with complete cessation of simulated bleeding in 60% of applications. This finding was consistent across all operators and both robots. There was no difference in the success rates with the 2 robots (p = 1.00). However, there were differences in fluid loss (p = 0.004) and application time (p < 0.001), with the larger (Wolverine) robot being faster and losing less fluid. CONCLUSION: Law enforcement tactical robots were consistently able to provide partial to complete hemorrhage control in a simulated extremity exsanguination. Consideration should be given to using this approach in care-under-fire and care-behind-the-barricade scenarios as well as further developing the technology and doctrine for robotic hemorrhage control.

Point-of-Care Ultrasound Use by EMS Providers in Out-of-Hospital Cardiac Arrest.

AIM: Paramedics received training in point-of-care ultrasound (POCUS) to assess for cardiac contractility during management of medical out-of-hospital cardiac arrest (OHCA). The primary outcome was the percentage of adequate POCUS video acquisition and accurate video interpretation during OHCA resuscitations. Secondary outcomes included POCUS impact on patient management and resuscitation protocol adherence. METHODS: A prospective, observational cohort study of paramedics was performed following a four-hour training session, which included a didactic lecture and hands-on POCUS instruction. The Prehospital Echocardiogram in Cardiac Arrest (PECA) protocol was developed and integrated into the resuscitation algorithm for medical non-shockable OHCA. The ultrasound (US) images were reviewed by a single POCUS expert investigator to determine the adequacy of the POCUS video acquisition and accuracy of the video interpretation. Change in patient management and resuscitation protocol adherence data, including end-tidal carbon dioxide (EtCO2) monitoring following advanced airway placement, adrenaline administration, and compression pauses under ten seconds, were queried from the prehospital electronic health record (EHR). RESULTS: Captured images were deemed adequate in 42/49 (85.7%) scans and paramedic interpretation of sonography was accurate in 43/49 (87.7%) scans. The POCUS results altered patient management in 14/49 (28.6%) cases. Paramedics adhered to EtCO2 monitoring in 36/36 (100.0%) patients with an advanced airway, adrenaline administration for 38/38 (100.0%) patients, and compression pauses under ten seconds for 36/38 (94.7%) patients. CONCLUSION: Paramedics were able to accurately obtain and interpret cardiac POCUS videos during medical OHCA while adhering to a resuscitation protocol. These findings suggest that POCUS can be effectively integrated into paramedic protocols for medical OHCA.

Delayed care in myocardial infarction and ischemic stroke patients during the COVID-19 pandemic.

COVID-19 has profound direct health consequences, however secondary effects were much broader as rates of hospital visits steeply declined for non-COVID-19 concerns, including myocardial infarction (MI) and stroke, with patients choosing to wait longer before symptoms convince them to seek medical attention. Thus, patients where ischemia leads to tissue loss should be a major concern. METHODS: The months of March to June 2019 and 2020 were compared to each other at 4 Denver area hospitals. Reduction in overall ED visits and an increase in patient refusal for emergency transport were clear in the data collected. During this period in 2019, 49 MI and 90 stroke patients were admitted. In 2020 this was 40 and 90 respectively. All were matched for age and gender. For MI patients ejection fraction and door to EKG and intervention times were measured. For stroke patients last known well time, time to evaluation, and modified Rankin scores were measured. RESULTS: 254 (8.12%) patients refused emergency services transportation before the pandemic compared to 479 (18.35%) during the pandemic (p-value <0.001, chi square test). In the MI cohort, no significant difference was detected in measured ejection fraction (48% vs 49% p-value = 0.682). Additionally, no significant difference was detected between door to EKG time or door to MI intervention time. During the pandemic 8 (22%) expired with an MI prior to discharge, compared to 2 (4%) before the pandemic. The stroke cohort Door to Evaluation Time, Time since last well known, and modified Rankin scores were all found to have insignificant differences. DISCUSSION: ED volume was significantly lower during the early stages of the pandemic. During this time however only death from cardiac events increased, in spite of similar ejection fractions at discharge. The cause of this remains unclear as ejection fraction similarities make it less attributable to loss of tissue than to other factors. Patient behavior significantly changed during the pandemic, making this a likely source of the increase in mortality seen.

In vivo dynamic characterization of the human tympanic membrane using pneumatic optical coherence tomography.

Decreased mobility of the human eardrum, the tympanic membrane (TM), is an essential indicator of a prevalent middle ear infection. The current diagnostic method to assess TM mobility is via pneumatic otoscopy, which provides subjective and qualitative information of subtle motion. In this study, a handheld spectral-domain pneumatic optical coherence tomography system was developed to simultaneously measure the displacement of the TM, air pressure inputs applied to a sealed ear canal, and to perform digital pneumatic otoscopy. A novel approach based on quantitative parameters is presented to characterize spatial and temporal variations of the dynamic TM motion. Furthermore, the TM motions of normal middle ears are compared with those of ears with middle ear infections. The capability of noninvasively measuring the rapid motion of the TM is beneficial to understand the complex dynamics of the human TM, and can ultimately lead to improved diagnosis and management of middle ear infections.

Randomized Controlled Trial of Point-of-Care Ultrasound Education for the Recognition of Tension Pneumothorax by Paramedics in Prehospital Simulation.

OBJECTIVE: The primary goal of this study was to determine if ultrasound (US) use after brief point-of-care ultrasound (POCUS) training on cardiac and lung exams would result in more paramedics correctly identifying a tension pneumothorax (TPTX) during a simulation scenario. METHODS: A randomized controlled, simulation-based trial of POCUS lung exam education investigating the ability of paramedics to correctly diagnose TPTX was performed. The US intervention group received a 30-minute cardiac and lung POCUS lecture followed by hands-on US training. The control group did not receive any POCUS training. Both groups participated in two scenarios: right unilateral TPTX and undifferentiated shock (no TPTX). In both scenarios, the patient continued to be hypoxemic after verified intubation with pulse oximetry of 86%-88% and hypotensive with a blood pressure of 70/50. Sirens were played at 65 decibels to mimic prehospital transport conditions. A simulation educator stated aloud the time diagnoses were made and procedures performed, which were recorded by the study investigator. Paramedics completed a pre-survey and post-survey. RESULTS: Thirty paramedics were randomized to the control group; 30 paramedics were randomized to the US intervention group. Most paramedics had not received prior US training, had not previously performed a POCUS exam, and were uncomfortable with POCUS. Point-of-care US use was significantly higher in the US intervention group for both simulation cases (P <.001). A higher percentage of paramedics in the US intervention group arrived at the correct diagnosis (77%) for the TPTX case as compared to the control group (57%), although this difference was not significantly different (P = 0.1). There was no difference in the correct diagnosis between the control and US intervention groups for the undifferentiated shock case. On the post-survey, more paramedics in the US intervention group were comfortable with POCUS for evaluation of the lung and comfortable decompressing TPTX using POCUS (P <.001). Paramedics reported POCUS was within their scope of practice. CONCLUSIONS: Despite being novice POCUS users, the paramedics were more likely to correctly diagnose TPTX during simulation after a brief POCUS educational intervention. However, this difference was not statistically significant. Paramedics were comfortable using POCUS and felt its use improved their TPTX diagnostic skills.

Otitis Media Middle Ear Effusion Identification and Characterization Using an Optical Coherence Tomography Otoscope.

OBJECTIVE: To determine the feasibility of detecting and differentiating middle ear effusions (MEEs) using an optical coherence tomography (OCT) otoscope. STUDY DESIGN: Cross-sectional study. SETTING: US tertiary care children's hospital. SUBJECTS AND METHODS: Seventy pediatric patients undergoing tympanostomy tube placement were preoperatively imaged using an OCT otoscope. A blinded reader quiz was conducted using 24 readers from 4 groups of tiered medical expertise. The primary outcome assessed was reader ability to detect presence/absence of MEE. A secondary outcome assessed was reader ability to differentiate serous vs nonserous MEE. RESULTS: OCT image data sets were analyzed from 45 of 70 total subjects. Blinded reader analysis of an OCT data subset for detection of MEE resulted in 90.6% accuracy, 90.9% sensitivity, 90.2% specificity, and intra/interreader agreement of 92.9% and 87.1%, respectively. Differentiating MEE type, reader identification of nonserous MEE had 70.8% accuracy, 53.6% sensitivity, 80.1% specificity, and intra/interreader agreement of 82.9% and 75.1%, respectively. Multivariate analysis revealed that age was the strongest predictor of OCT quality. The mean age of subjects with quality OCT was 5.01 years (n = 45), compared to 2.54 years (n = 25) in the remaining subjects imaged (P = .0028). The ability to capture quality images improved over time, from 50% to 69.4% over the study period. CONCLUSION: OCT otoscopy shows promise for facilitating accurate MEE detection. The imageability with the prototype device was affected by age, with older children being easier to image, similar to current ear diagnostic technologies.

The next nine minutes: Lessons learned from the large-scale active shooter training prior to the STEM school shooting.

OBJECTIVE: As the incidence of active shooters increase, local emergency response has also changed. South Metro Fire Rescue coordinated a series of hyper-realistic active shooter simulation drills involving multiple agencies. METHODS: "The Next Nine Minutes" was one of the largest active shooter drills performed to date with 904 personnel that were trained in 18 mass casualty active shooter drills. Evaluation was from point of injury to and including care in the operating room (OR), and evaluation of real-time system logistics. RESULTS: A total of 126 patients in Cut Suits® received a total of 479 procedures such as needle decompressions, cricothyrotomies, tourniquets, wound packs, and chest tubes. Central to this exercise, law enforcement (LE) established a warm zone from the initial shooting. EMS was able to move into the facility, locate casualties, extract the first victim, move them to a casualty collection point (CCP), and transport them to safety within 12 minutes. CONCLUSIONS: Strengths and weaknesses were identified in prehospital and in-hospital care. These included what roles agencies play in a true event, specific timing in establishing areas such as the warm zone and CCP, transportation, and logistics at the accepting hospitals. Only after the barriers to success were identified and addressed did the timing of casualty movement drastically improve. Lessons learned from this training were ultimately used to save lives at the STEM School, Highlands Ranch, and Colorado Shooting. This in situ immersion training should be practiced as a whole system.

A "human-proof pointy-end": a robotically applied hemostatic clamp for care-under-fire

Summary: Providing the earliest hemorrhage control is now recognized as a shared responsibility of all members of society, including both the lay public and professionals, consistent with the Stop the Bleed campaign. However, providing early hemorrhage control in a hostile environment, such as the scene of a mass shooting, is extremely challenging. In such settings, the first access to a bleeding victim may be robotic. An all-purpose bomb robot was thus retrofitted with a commercial, off-the-shelf wound clamp and successfully applied to an extremity exsanguination simulator as a demonstration of remote robotic hemorrhage control. As this method can potentially control extremity hemorrhage, further development of the techniques, equipment and, most importantly, the guidelines and rules of engagement should continue. We suggest that in order to minimize the loss of life during an active shooter incident, the armamentarium of prehospital medical resources may be extended to include law-enforcement robots.

Magnetomotive Displacement of the Tympanic Membrane Using Magnetic Nanoparticles: Toward Enhancement of Sound Perception.

OBJECTIVE: A novel hearing-aid scheme using magnetomotive nanoparticles (MNPs) as transducers in the tympanic membrane (TM) is proposed, aiming to noninvasively and directly induce a modulated vibration on the TM. METHODS: In this feasibility study, iron oxide (Fe3O4) nanoparticles were applied on ex vivo rat TM tissues and allowed to diffuse over ∼2 h. Subsequently, magnetic force was exerted on the MNP-laden TM via a programmable electromagnetic solenoid to induce the magnetomotion. Optical coherence tomography (OCT), along with its phase-sensitive measurement capabilities, was utilized to visualize and quantify the nanometer-scale vibrations generated on the TM tissues. RESULTS: The magnetomotive displacements induced on the TM were significantly greater than the baseline vibration of the TM without MNPs. In addition to a pure frequency tone, a chirped excitation and the corresponding spectroscopic response were also successfully generated and obtained. Finally, visualization of volumetric TM dynamics was achieved. CONCLUSION: This study demonstrates the effectiveness of magnetically inducing vibrations on TMs containing iron oxide nanoparticles, manipulating the amplitude and the frequency of the induced TM motions, and the capability of assessing the magnetomotive dynamics via OCT. SIGNIFICANCE: The results demonstrated here suggest the potential use of this noninvasive magnetomotive approach in future hearing aid applications. OCT can be utilized to investigate the magnetomotive dynamics of the TM, which may either enhance sound perception or magnetically induce the perception of sound without the need for acoustic speech signals.

Noninvasive in vivo optical coherence tomography tracking of chronic otitis media in pediatric subjects after surgical intervention.

In an institutional review board-approved study, 25 pediatric subjects diagnosed with chronic or recurrent otitis media were observed over a period of six months with optical coherence tomography (OCT). Subjects were followed throughout their treatment at the initial patient evaluation and preoperative consultation, surgery (intraoperative imaging), and postoperative follow-up, followed by an additional six months of records-based observation. At each time point, the tympanic membrane (at the light reflex region) and directly adjacent middle-ear cavity were observed in vivo with a handheld OCT probe and portable system. Imaging results were compared with clinical outcomes to correlate the clearance of symptoms in relation to changes in the image-based features of infection. OCT images of most all participants showed the presence of additional infection-related biofilm structures during their initial consultation visit and similarly for subjects imaged intraoperatively before myringotomy. Subjects with successful treatment (no recurrence of infectious symptoms) had no additional structures visible in OCT images during the postoperative visit. OCT image findings suggest surgical intervention consisting of myringotomy and tympanostomy tube placement provides a means to clear the middle ear of infection-related components, including middle-ear fluid and biofilms. Furthermore, OCT was demonstrated as a rapid diagnostic tool to prospectively monitor patients in both outpatient and surgical settings.

Quantitative Pneumatic Otoscopy Using a Light-Based Ranging Technique.

Otitis media is the leading cause of hearing loss in children. It is commonly associated with fluid in the ear, which can result in up to 45 dB of hearing loss for extended periods of time during a child's most important developmental years. Accurate assessment of middle ear effusions is an important part of understanding otitis media. Current technologies used to diagnose otitis media with effusion are pneumatic otoscopy, tympanometry, and acoustic reflectometry. While all of these techniques can reasonably diagnose the presence of an effusion, they provide limited information about the infection present behind the tympanic membrane.We have developed a technique based on low-coherence interferometry-a non-invasive optical ranging technique capable of sensing depth-resolved microscopic scattering features through the eardrum-to quantify eardrum thickness and integrity, as well as detect any effusion, purulence, or biofilm behind the tympanic membrane. In this manuscript, the technique is coupled with a pneumatic otoscope to measure minute deflections of the tympanic membrane from insufflation pressure stimuli. This results in quantitative measurements of tympanic membrane mobility, which may be used to gain a better understanding of the impact of infection on the membrane dynamics. A small pilot study of 15 subjects demonstrates the ability of pneumatic low-coherence interferometry to quantitatively differentiate normal ears from ears with effusions present. Analysis of the strengths and weaknesses of the technique, as well as focus areas of future research, is also discussed.

Ratiometric analysis of optical coherence tomography-measured in†vivo retinal layer thicknesses for the detection of early diabetic retinopathy.

Influence of diabetes mellitus (DM) and diabetic retinopathy (DR) on parafoveal retinal thicknesses and their ratios was evaluated. Six retinal layer boundaries were segmented from spectral-domain optical coherence tomography images using open-source software. Five study groups: (1) healthy control (HC) subjects, and subjects with (2) controlled DM, (3) uncontrolled DM, (4) controlled DR and (5) uncontrolled DR, were identified. The one-way analyses of variance (ANOVA) between adjacent study groups (i. e. 1 with 2, 2 with 3, etc) indicated differences in retinal thicknesses and ratios. Overall retinal thickness, ganglion cell layer (GCL) thickness, inner plexiform layer (IPL) thickness, and their combination (GCL+ IPL), appeared to be significantly less in the uncontrolled DM group when compared to controlled DM and controlled DR groups. Although the combination of nerve fiber layer (NFL) and GCL, and IPL thicknesses were not different, their ratio, (NFL+GCL)/IPL, was found to be significantly higher in the controlled DM group compared to the HC group. Comparisons of the controlled DR group with the controlled DM group, and with the uncontrolled DR group, do not show any differences in the layer thicknesses, though several significant ratios were obtained. Ratiometric analysis may provide more sensitive parameters for detecting changes in DR. Picture: A representative segmented OCT image of the human retina is shown.

Quantitative characterization of mechanically indented in vivo human skin in adults and infants using optical coherence tomography.

Influenced by both the intrinsic viscoelasticity of the tissue constituents and the time-evolved redistribution of fluid within the tissue, the biomechanical response of skin can reflect not only localized pathology but also systemic physiology of an individual. While clinical diagnosis of skin pathologies typically relies on visual inspection and manual palpation, a more objective and quantitative approach for tissue characterization is highly desirable. Optical coherence tomography (OCT) is an interferometry-based imaging modality that enables in vivo assessment of cross-sectional tissue morphology with micron-scale resolution, which surpasses those of most standard clinical imaging tools, such as ultrasound imaging and magnetic resonance imaging. This pilot study investigates the feasibility of characterizing the biomechanical response of in vivo human skin using OCT. OCT-based quantitative metrics were developed and demonstrated on the human subject data, where a significant difference between deformed and nondeformed skin was revealed. Additionally, the quantified postindentation recovery results revealed differences between aged (adult) and young (infant) skin. These suggest that OCT has the potential to quantitatively assess the mechanically perturbed skin as well as distinguish different physiological conditions of the skin, such as changes with age or disease.

Low-cost hand-held probe for depth-resolved low-coherence interferometry.

We report on the development of a low-cost hand-held low-coherence interferometric imaging system based on the principle of linear optical coherence tomography (Linear OCT), a technique which was first proposed in the early 2000s as a simpler alternative to the conventional time-domain and Fourier-domain OCT. A bench-top implementation of the proposed technique is first presented and validated. The axial resolution, SNR, and sensitivity roll-of of the system was estimated to be 5.2 µm and 80 dB, and 3.7 dB over a depth of 0.15 mm, respectively. After validating the bench-top system, two hand-held probe implementations for contact-based imaging and in vivo human tympanic membrane imaging are presented. The performance of the proposed system was compared with a research-grade state-of-the-art Fourier-domain low coherence interferometry (LCI) system by imaging several biological and non-biological samples. The results of this study suggest that the proposed system might be a suitable choice for applications where imaging depth and SNR can be traded for lower cost and simpler optical design.

Non-invasive optical assessment of viscosity of middle ear effusions in otitis media.

Eustachian tube dysfunction can cause fluid to collect within the middle ear cavity and form a middle ear effusion (MEE). MEEs can persist for weeks or months and cause hearing loss as well as speech and learning delays in young children. The ability of a physician to accurately identify and characterize the middle ear for signs of fluid and/or infection is crucial to provide the most appropriate treatment for the patient. Currently, middle ear infections are assessed with otoscopy, which provides limited and only qualitative diagnostic information. In this study, we propose a method utilizing cross-sectional depth-resolved optical coherence tomography to noninvasively measure the diffusion coefficient and viscosity of colloid suspensions, such as a MEE. Experimental validation of the proposed technique on simulated MEE phantoms with varying viscosity and particulate characteristics is presented, along with some preliminary results from in vivo and ex vivo samples of human MEEs. In vivo Optical Coherence Tomography (OCT) image of a human tympanic membrane and Middle Ear Effusion (MEE) (top), with a CCD image of the tympanic membrane surface (inset). Below is the corresponding time-lapse M-mode OCT data acquired along the white dotted line over time, which can be analyzed to determine the Stokes-Einstein diffusion coefficient of the effusion.

Reliability of the Faces, Legs, Activity, Cry, and Consolability Scale in Assessing Acute Pain in the Pediatric Emergency Department.

OBJECTIVES: The Faces, Legs, Activity, Cry, and Consolability (FLACC) scale is one of the most widely utilized observational pain assessment scales in clinical practice. Although designed and validated to assess postoperative pain, the tool is currently applied to assess acute pain in multiple settings, including the emergency department. Scarce literature exists evaluating the reliability of the FLACC scale in the nonsurgical population and none in the emergency department. We sought to investigate the reliability of the FLACC scale in assessing acute pain in the pediatric emergency department and to examine the sensitivity of FLACC scores after the administration of analgesia. METHODS: In phase 1 of this prospective study, a series of 2 independent evaluators, blinded to each other's evaluations, scored 66 patients using the FLACC tool. Degree of concordance among the 6 dyads was used to measure interrater reliability. In phase 2, FLACC scores were obtained just before the administration of analgesia in 35 patients and measured at 30 and at 60 minutes after administration. RESULTS: Among the 6 dyads of evaluators, Kendall W demonstrated a strong concordance (27 of 30 measures; range, 0.63-1.00) for individual components of the scale and for the composite scores (range, 0.85-0.96). Significant mean reductions from preanalgesia FLACC scores [5.54; 95% confidence interval (CI), 4.79-6.30] were seen at 30 minutes (2.00; 95% CI, 1.61-2.39) and 60 minutes (1.14; 95% CI, 0.79-1.50) postanalgesia (P < 0.0001 for all comparisons). CONCLUSIONS: The FLACC scale demonstrated high interrater reliability for both individual FLACC items and total scores in a convenience sample of patients aged 6 months to 5 years in a pediatric emergency department. It seems to be an appropriate observational tool to assess acute pain in this population.

Rapid diagnosis and differentiation of microbial pathogens in otitis media with a combined Raman spectroscopy and low-coherence interferometry probe: toward in vivo implementation.

We investigate and demonstrate the feasibility of using a combined Raman scattering (RS) spectroscopy and low-coherence interferometry (LCI) probe to differentiate microbial pathogens and improve our diagnostic ability of ear infections [otitis media (OM)]. While the RS probe provides noninvasive molecular information to identify and differentiate infectious microorganisms, the LCI probe helps to identify depth-resolved structural information as well as to guide and monitor positioning of the Raman spectroscopy beam for relatively longer signal acquisition times. A series of phantom studies, including the use of human middle ear effusion samples, were performed to mimic the conditions of in vivo investigations. These were also conducted to validate the feasibility of using this combined RS/LCI probe for point-of-care diagnosis of the infectious pathogen(s) in OM patients. This work establishes important parameters for future in vivo investigations of fast and accurate determination and diagnosis of infectious microorganisms in OM patients, potentially improving the efficacy and outcome of OM treatments, and importantly reducing the misuse of antibiotics in the presence of viral infections.

Ratiometric analysis of in vivo retinal layer thicknesses in multiple sclerosis.

We performed ratiometric analysis of retinal optical coherence tomography images for the first time in multiple sclerosis (MS) patients. The ratiometric analysis identified differences in several retinal layer thickness ratios in the cohort of MS subjects without a history of optic neuritis (ON) compared to healthy control (HC) subjects, and there was no difference in standard retinal nerve fiber layer thickness (RNFLT). The difference in such ratios between HC subjects and those with mild MS-disability, without a difference in RNFLT, further suggests the possibility of using layer ratiometric analysis for detecting early retinal changes in MS. Ratiometric analysis may be useful and potentially more sensitive for detecting disease changes in MS.

A Mosaicking Approach for In Vivo Thickness Mapping of the Human Tympanic Membrane Using Low Coherence Interferometry.

The thickness of the human tympanic membrane (TM) is known to vary considerably across different regions of the TM. Quantitative determination of the thickness distribution and mapping of the TM is of significant importance in hearing research, particularly in mathematical modeling of middle-ear dynamics. Change in TM thickness is also associated with several middle-ear pathologies. Determination of the TM thickness distribution could therefore also enable a more comprehensive diagnosis of various otologic diseases. Despite its importance, very limited data on human TM thickness distribution, obtained almost exclusively from ex vivo samples, are available in the literature. In this study, the thickness distribution for the in vivo human TM is reported for the first time. A hand-held imaging system, which combines a low coherence interferometry (LCI) technique for single-point thickness measurement, with video-otoscopy for recording the image of the TM, was used to collect the data used in this study. Data were acquired by pointing the imaging probe over different regions of the TM, while simultaneously recording the LCI and concomitant TM surface video image data from an average of 500 locations on the TM. TM thickness distribution maps were obtained by mapping the LCI imaging sites onto an anatomically accurate wide-field image of the TM, which was generated by mosaicking the sequence of multiple small field-of-view video-otoscopy images. Descriptive statistics of the thickness measurements obtained from the different regions of the TM are presented, and the general thickness distribution trends are discussed.

Detection of retinal blood vessel changes in multiple sclerosis with optical coherence tomography.

Although retinal vasculitis is common in multiple sclerosis (MS), it is not known if MS is associated with quantitative abnormalities in retinal blood vessels (BVs). Optical coherence tomography (OCT) is suitable for examining the integrity of the anterior visual pathways in MS. In this paper we have compared the size and number of retinal blood vessels in patients with MS, with and without a history of optic neuritis (ON), and control subjects from the cross-sectional retinal images from OCT. Blood vessel diameter (BVD), blood vessel number (BVN), and retinal nerve fiber layer thickness (RNFLT) were extracted from OCT images collected from around the optic nerves of 129 eyes (24 control, 24 MS + ON, 81 MS-ON) of 71 subjects. Associations between blood vessel metrics, MS diagnosis, MS disability, ON, and RNFLT were evaluated using generalized estimating equation (GEE) models. MS eyes had a lower total BVD and BVN than control eyes. The effect was more pronounced with increased MS disability, and persisted in multivariate models adjusting for RNFLT and ON history. Twenty-nine percent (29%) of MS subjects had fewer retinal blood vessels than all control subjects. MS diagnosis, disability, and ON history were not associated with average blood vessel size. The relationship between MS and lower total BVD/BVN is not accounted for by RNFLT or ON. Further study is needed to determine the relationship between OCT blood vessel metrics and qualitative retinal blood vessel abnormalities in MS.