Acoustic radiation force impulse and ultrasound contrast agent evokes arrhythmias in the rabbit heart

Abstracts Background: Liver stiffness (LS) measurement by elastographic methods is a noninvasive technique for the evaluation of liver fibrosis, which could also be used for predicting the presence of esophageal varices (EV) in patients with liver cirrhosis. Aim: The aim of this study was to evaluate two ultrasound based elastographic methods as non-invasive markers for predicting the presence of EV, in a cohort of alcoholic liver cirrhosis patients. Material and Method: The study included 77 patients diagnosed with compensated alcoholic liver cirrhosis, who underwent both upper endoscopy and LS assessment by two elastographic methods -Transient Elastography (TE) (Fibroscan/EchoSens) and Point shear wave elastography - Virtual Touch Tissue Quantification (VTQ) (Siemens Acuson S2000). Reliable LS measurements were defined for both methods as the median values of 10 measurements with an interquartile range/ median ratio (IQR/M) < 30%. We used TE as the reference method to diagnose liver cirrhosis (LS  12 kPa) [1]. Patients with ascites were excluded due to the impossibility to perform TE. Results: 56 patients out of 77 had valid measurements by both elastographic methods and were included in the final analysis, 40/56 patients with EV. The best cut-off values to rule out the presence of EV in our cohort of alcoholic liver cirrhosis patients, with a NPV of 100% were:  20.1 kPa for TE (AUROC 0.9; sensitivity-100%; specificity- 28%; PPV- 56%; NPV100%, Lr- 0, LR+1.38) and  2.1 m/s for VTQ (AUROC 0.85; sensitivity-100%; specificity- 18%; PPV- 52%; NPV- 100%, Lr- 0, LR+1.21). Conclusion: Using for TE the cut-off value  20.1 kPa and VTQ  2.1 m/s we can rule out quite accurately the presence of EV in patients with alcoholic liver cirrhosis. Reference: 1. Tsochatzis EA, Gurusamy KS, Ntaoula S, Cholongitas E, Davidson BR, Burroughs AK. Elastography for the diagnosis of severity of fibrosis in chronic liver disease: a meta-analysis of diagnostic accuracy. J Hepatol 2011;54:650-659. Utility of bedside ultrasonography to evaluate the ocular injury in pediatric traumatic brain and spinal injuries Renu Rani,1,2 Deepak Agrawal,2 Pankaj Kumar,2 Summi2 1 All India Institute of Medical Sciences, New Delhi, Delhi, India, 2 Department of Neurosurgery, Jai Prakash Narain Apex Trauma Centre, AIIMS, New Delhi, India Introduction: Ocular trauma refers to any injury to the eye. Ocular trauma occurs frequently in India and constitutes a major health problem like in other developing countries. Aim: To understand the patterns of ocular trauma in Indian pediatric patients (< 18 years of age) presenting to a single centre with traumatic brain and spinal injuries Methods and Materials: A prospective study was carried out on all TBI and spinal injury patients admitted in Neurosurgery ICU from Jan 2016 - March 2017. Ultrasound of eye was done by nurses using linear probe on Sonosite TurboÒ . Type of ocular Injury, Pupils Reactivity, conjunctival hemorrhage and Nerve Injury (II/III) were identified and recorded for all the patients. Results: A total of 377 patients were screened of which 41 were pediatric patients. The mean age was 9.8 years (range 2 17). Male: Female was 3.1:1 with a mean GCS of 9.8 (range 3 15). Patients had associated TBI in 29 (70.7%) and spinal injury in 12(29.2%). Mode of injury was RTA in 11 (26.8%), fall in 25 (60.9%), assault in 2 (4.8%) and other causes in 3 (7.3%) patients. The most common ocular injury was closed globe injury (78.1%) followed by open globe injuries (3.5%) and orbital injuries (3.1%). 34.1 % patients had optic and/or occulomotor nerve palsies. Conclusion: Our study showed that significant percentage of TBI and spinal injury patients will have occular trauma in the pediatric age

S115

group. Ocular trauma can be very easily assessed using bedside ultrasound by nurses for the early detection of the eye injuries and early management of patients.

Acoustic radiation force impulse and ultrasound contrast agent evokes arrhythmias in the rabbit heart Kazuma Rifu,1 Sasanuma Hideki,1 Noriya Takayama,2 Naotaka Nitta,3 Motoki Furuya,4 Yukiyo Ogata,5 Iwaki Akiyama,4 Alan K Lefor,1 Nobuyuki Taniguchi2 1 Department of Surgery, Division of Gastroenterological, General and Transplant Surgery, Jichi Medical University Hospital, Shimotsuke Yakushiji, Tochigi, Japan, 2 Department of Clinical Laboratory Medicine, Jichi Medical University, Shimotsuke Yakushiji, Tochigi, Japan, 3 Health Research Institute, National Institute of Advanced Industrial Science and Technology(AIST), Tsukuba, Ibaraki, Japan, 4 Faculty of Life and Medical Sciences Medical Ultrasound Research Center, Doshisha University, Kyotanabe, Kyoto, Japan, 5 Department of Cardiology, Jichi Medical University, Shimotsuke Yakushiji, Tochigi, Japan Introduction: Acoustic Radiation Force Impulse[ARFI] ultrasound elastography has been widely introduced as a diagnostic modality for liver and breast masses. We previously reported that arrhythmias were observed at a mechanical index [MI] of 1.8 with ARFI and concomitant administration of an ultrasound contrast agent[UCA] in rabbits. The aim of this study was to identify the location of the arrhythmias in a heart using a new system (Microsonic co., Tokyo, Japan) which transmits ARFI from the probe used for B-mode imaging of the heart. Methods: Under general anesthesia, seven rabbits were exposed to ARFI. Using the new transducer, cardiac B-mode images (4 chamber view, left ventricle long-axis view) were obtained through the intercostal space. We chose three points along the impulse conduction system of the heart: (1) right ventricle, (2) right atrium and (3) left ventricular wall.We confirmed the occurrence of arrhythmias and the shape of arrhythmias with and without UCA (perfluorobutane (SonazoidTM)). (at double the clinical dose). Two minutes after intravenous injection of the UCA, ARFI was transmitted with a 1.0 msec pulse duration delayed 200msec after the R wave. Thirty exposures were synchronized with one exposure per three heart beats. The MI of the ARFI exposure ranged from 0.84 to 1.16. Results: e-para id="spara003_11564_107">Arrhythmias were not observed using ARFI without UCA. For ARFI exposure with UCA, an average of 2.85 arrhythmias were observed (range 0-7). There were no fatal arrhythmias. Arrythmias tend to occur from (1) and (2) rather than (3). The shape of arrhythmias were single ventricular or supraventricular extra-systolic waves. Arrhythmias from the right (1), (2) and left (3) heart had a reversed shape. Discussion: Using this new system, the rabbit heart exposed to ARFI had more reliable focal positions. The MI used in this study was similar to that used in clinical setting of ARFI. There was no significant difference in the frequency of arrhythmias among the three points of ARFI exposure. However, reversed shape arrhythmias may indicate that ARFI exposure actually stimulated the right or left-sided impulse conduction system. Conclusion: Extra-systolic activity at different origins was observed under similar clinical conditions using ARFI with infusion of an UCA. Ultrasound practitioners should know this adverse reaction, even if the MI is below the previously determined value of 1.9, especially when imaging near the conduction system.

Does ultrasound gel used during needle guided procedures put patients at risk for nosocomial infection? Kevin T Rooker CIVCO Medical Solutions, Coralville, Iowa, United States