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To improve the pathophysiological understanding of visual changes observed in astronauts, we aimed to use quantitative MRI to measure anatomic and physiological responses during a ground-based spaceflight analog (head-down tilt, HDT) combined with increased ambient carbon dioxide (CO 2 ). Six healthy, male subjects participated in the double-blinded, randomized crossover design study with two conditions: 26.5 h of -12° HDT with ambient air and with 0.5% CO 2 , both followed by 2.5-h exposure to 3% CO 2 Volume and mean diffusivity quantification of the lateral ventricle and phase-contrast flow sequences of the internal carotid arteries and cerebral aqueduct were acquired at 3 T. Compared with supine baseline, HDT (ambient air) resulted in an increase in lateral ventricular volume ( P = 0.03). Cerebral blood flow, however, decreased with HDT in the presence of either ambient air or 0.5% CO 2 ( P = 0.002 and P = 0.01, respectively); this was partially reversed by acute 3% CO 2 exposure. Following HDT (ambient air), exposure to 3% CO 2 increased aqueductal cerebral spinal fluid velocity amplitude ( P = 0.01) and lateral ventricle cerebrospinal fluid (CSF) mean diffusivity ( P = 0.001). We concluded that HDT causes alterations in cranial anatomy and physiology that are associated with decreased craniospinal compliance. Brief exposure to 3% CO 2 augments CSF pulsatility within the cerebral aqueduct and lateral ventricles. NEW & NOTEWORTHY Head-down tilt causes increased lateral ventricular volume and decreased cerebrovascular flow after 26.5 h. Additional short exposure to 3% ambient carbon dioxide levels causes increased cerebrovascular flow associated with increased cerebrospinal fluid pulsatility at the cerebral aqueduct. Head-down tilt with chronically elevated 0.5% ambient carbon dioxide and acutely elevated 3% ambient carbon dioxide causes increased mean diffusivity of cerebral spinal fluid within the lateral ventricles., (Copyright © 2017 the American Physiological Society.)

Introduction: An experimental epidural hematoma model was used to study the relation of ultrasound indices, namely, transcranial color-coded-Doppler (TCCD) derived pulsatility index (PI), optic nerve sheath diameter (ONSD), and pupil constriction velocity (V) which was derived from a consensual sonographic pupillary light reflex (PLR) test with invasive intracranial pressure (ICP) measurements., Material and Methods: Twenty rabbits participated in the study. An intraparenchymal ICP catheter and a 5F Swan-Ganz catheter (SG) for the hematoma reproduction were used. We successively introduced 0.1 mL increments of autologous blood into the SG until the Cushing reaction occurred. Synchronous ICP and ultrasound measurements were performed accordingly., Results: A constant increase of PI and ONSD and a decrease of V values were observed with increased ICP values. The relationship between the ultrasound variables and ICP was exponential; thus curved prediction equations of ICP were used. PI, ONSD, and V were significantly correlated with ICP (r² = 0.84 ± 0.076, r² = 0.62 ± 0.119, and r² = 0.78 ± 0.09, resp. (all P < 0.001))., Conclusion: Although statistically significant prediction models of ICP were derived from ultrasound indices, the exponential relationship between the parameters underpins that results should be interpreted with caution and in the current experimental context.

Modern medical practice has become extremely dependent upon diagnostic imaging technologies to confirm the results of clinical examination and to guide the response to therapies. Of the various diagnostic imaging techniques, ultrasound is the most portable modality and one that is repeatable, dynamic, relatively cheap, and safe as long as the imaging provided is accurately interpreted. It is, however, the most user-dependent, a characteristic that has prompted the development of remote guidance techniques, wherein remote experts guide distant users through the use of information technologies. Medical mission work often brings specialist physicians to less developed locations, where they wish to provide the highest levels of care but are often bereft of diagnostic imaging resources on which they depend. Furthermore, if these personnel become ill or injured, their own care received may not be to the standard they have left at home. We herein report the utilization of a compact hand-carried remote tele-ultrasound system that allowed real-time diagnosis and follow-up of an acutely torn adductor muscle by a team of ultrasonographers, surgeons, and physicians. The patient was one of the mission surgeons who was guided to self-image. The virtual network of supporting experts was located across North America, whereas the patient was in Lome, Togo, West Africa. The system consisted of a hand-carried ultrasound, the output of which was digitized and streamed to the experts within standard voice-over-Internet-protocol software with an embedded simultaneous videocamera image of the ultrasonographer's hands using a customized graphical user interface. The practical concept of a virtual tele-ultrasound support network was illustrated through the clinical guidance of multiple physicians, including National Aeronautics and Space Administration Medical Operations remote guiders, Olympic team-associated surgeons, and ultrasound-focused emergentologists.

Objectives: To develop an animal model of rhinosinusitis in microgravity, to characterize the behavior of intracavitary fluid in microgravity, and to assess the accuracy of ultrasonographic (US) diagnosis in microgravity., Design: An animal model of acute sinusitis was developed in anesthetized swine by creating a window into a frontal sinus to allow unilateral catheter placement and injection of fluid. We performed US examinations in normal and microgravity environments on control and sinusitis conditions and recorded these for later interpretation., Setting: Henry Ford Hospital and the National Aeronautics and Space Administration (NASA) Microgravity Research Facility in Houston, Texas., Subjects: Ground (normal-gravity) experiments were conducted on anesthetized swine (n = 4) at Henry Ford Hospital before the microgravity experiments (n = 4) conducted in the NASA Microgravity Research Facility., Main Outcome Measure: Ultrasound visualization of fluid cavity., Results: Results of bilateral US examinations before fluid injection demonstrated typical air-filled sinuses. After unilateral injection of 1 mL of fluid, a consistent air-fluid interface was observed on the catheterized side at ground conditions. Microgravity conditions caused the rapid (<10-second) dissolution of the air-fluid interface, associated with uniform dispersion of the fluid to the walls of the sinus. The air-fluid interface reformed on return to normal gravity., Conclusions: The US appearance of fluid in nasal sinuses during microgravity is characterized in the large animal model. On the introduction of microgravity, the typical air-fluid interface disassociates, and fluid lining the sinus can be observed. Such fluid behavior can be used to develop diagnostic criteria for acute bacterial rhinosinusitis in the microgravity environment.

Introduction: Urinary obstruction (UO) or failure to void has been observed during several episodes of short-duration spaceflight, necessitating bladder catheterization. It should be considered a possible medical condition in long-duration space missions as well. Antiemetics used early in space flight add to the risk and severity of voiding problems, along with the sensory and psychological peculiarities of voiding without gravity and in the unusual setting of a spacecraft. Urolithiasis due to the above-normal calcium excretion increases the risk of UO in long duration space missions. Finally, the individual risk of UO is higher against the background of preexisting conditions such as benign prostatic hyperplasia (BPH) or urethral stricture. Both acute retention and ureteral obstruction are associated with substantial patient distress, and carry a risk of urosepsis and/or acute renal failure. If UO in orbital flight is unresolved or complicated, it would likely result in crew emergency return from orbit. Exploration missions, however, may require means for definitive treatment of urinary tract obstruction. This study documents successful ultrasound-guided percutaneous catheterization of the urinary bladder in microgravity. A porcine model of urethral occlusion was used. The results demonstrate an additional capability from our previous investigations describing endoscopic catheterization and stenting of the ureters in microgravity conditions., Methods: In an anesthetized porcine model, a Foley catheter was placed in the bladder and clamped after instillation of 200 ml of colored liquid. The bladder was visualized and then drained under ultrasound guidance through suprapubic puncture, employing a 10.3 F pigtail catheter with introducer. The procedural elements were conducted only during microgravity portions of the parabolic flight., Results: Ultrasound imaging was used to successfully perform image-guided percutaneous puncture through the anterior bladder wall with the catheter, without injury to adjacent organs. The percutaneous catheter was able to successfully drain the bladder in microgravity conditions., Conclusions: Percutaneous bladder catheterization and drainage can be successfully performed in weightless conditions under ultrasound guidance. Ultrasound provides a low-power, portable means to safely conduct minimally invasive procedures in pertinent organs and tissues. Percutaneous bladder catheterization is a standard procedure when luminal bladder catheterization is not possible; this technique can be successfully modified for use in space medicine applications.

Introduction: An intrathoracic injury may be disastrous to a crew-member aboard the International Space Station (ISS) if the diagnosis is missed or delayed. Symptomatic or clinically suspicious thoracic trauma is treated as a surgical emergency on Earth, usually with immediate stabilization and rapid transport to a facility that is able to deliver the appropriate medical care. A similar approach is planned for the ISS; however, an unnecessary evacuation would cause a significant mission impact and an exorbitant expense., Hypothesis: The use of ultrasound imaging for the detection of pneumothorax and hemothorax in microgravity is both possible and practical., Methods: Sonography was performed on anesthetized pigs in a ground-based laboratory (n = 4) and microgravity conditions (0 G) during parabolic flight (n = 4). Aliquots of air (50-500 ml) or saline (10-200 ml) were introduced into the pleural space to simulate pneumothorax and hemothorax, respectively., Results: The presence of "lung sliding" excluded pnemothorax. In microgravity, a loss of "lung sliding" was noted simultaneously in the anterior and posterior sonographic windows after 100 ml of air was introduced into the chest, indicating pneumothorax. The presence of the fluid layer in simulated hemothorax was noted in the anterior and posterior sonographic windows after 50 ml of fluid was injected into the pleural space. During the microgravity phase, the intrapleural fluid rapidly redistributed so that it could be detected using either anterior or posterior sonographic windows., Conclusion: Modest to severe pneumothorax and hemothorax can be diagnosed using ultrasound in microgravity.