Multi-parametric functional ultrasound imaging of cerebral hemodynamics in a cardiopulmonary resuscitation model

Abstract

Patient mortality at one year reaches 90% after out-of-hospital cardiac arrest and resuscitation. Temperature management is one of the main strategies proposed to improve patient outcome after resuscitation and preclinical studies have shown neuroprotective effects when hypothermia is achieved rapidly, although the underlying mechanisms have not yet been elucidated. State-of-the-art brain imaging technologies can bring new insights into the early cerebral events taking place post cardiac arrest and resuscitation. In this paper, we characterized cerebral hemodynamics in a post-cardiac arrest rabbit model using functional ultrasound imaging. Ultrasound datasets were processed to map the dynamic changes in cerebral blood flow and cerebral vascular resistivity with a 10 second repetition rate while animals underwent cardiac arrest and a cardiopulmonary resuscitation. We report that a severe transient hyperemia takes place in the brain within the first twenty minutes post resuscitation, emphasizing the need for fast post-cardiac arrest care. Furthermore, we observed that this early hyperemic event is not spatially homogeneous and that maximal cerebral hyperemia happens in the hippocampus. Finally, we show that rapid cooling induced by total liquid ventilation reduces early cerebral hyperemia, which could explain the improved neurological outcome reported in preclinical studies.

Effects of the duration of postresuscitation hyperoxic ventilation on neurological outcome and survival in an asphyxial cardiac arrest rat model

“…Consistent with previous animal studies, inhaling 100% oxygen immediately after resuscitation greatly improved MAP in this study 40 . Improved MAP can affect brain blood flow, brain tissue oxygen delivery, and the course of ischemic-reperfusion brain injury after cardiac arrest 41,42 . Unfortunately, exposure to hyperoxia following resuscitation will also amplify the production of oxygen free radicals and promote free radical-generated damage contributing to cerebral injury and cardiac dysfunction 43,44 .…”

Fluorescence, ultrasonic and photoacoustic imaging for analysis and diagnosis of diseases

“…31,32 Hence, substantial efforts have been made to develop improved ultrasonic imaging methods, including ultrasensitive, quantitative, high-resolution and high-frequency ultrasonic imaging, as well as 4D functional ultrasonic imaging, aimed at improving the accuracy of tumor diagnosis. [109][110][111][112][113][114][115][116][117] By combination with other image analysis techniques (e.g., artificial intelligence (AI) and deep learning), professionals can reduce interference from false positive signals and effectively determine the boundary of tumor tissues. 31,32,115 In 2017, Dong and coworkers developed an adaptive fuzzy C-means (FCM) method based on the Hausdorff distance definition to segment the ultrasonic imaging of breast cancer by adaptive selection of adjacent regions of each pixel for distance measurement and centroid updating.…”

“…125 The CEUS imaging modality has had many types of clinical impact on detection and diagnosis, such as tumors in different tissues (e.g., liver, kidney, uterus, prostate, thyroid, and mammary gland), lymph node metastasis, diverse inflammations, as well as acute kidney injury. [108][109][110][111][112][113][114][115] Compared to GSUS and DUS imaging modalities, the existence of ultrasonic contrast agents in the CEUS imaging method can improve the resolution and sensitivity of ultrasonic diagnosis by enhancing echobackscatter by the contrast media. 106,126 One kind of commercial ultrasonic contrast agents, e.g., Sonovue, is made of the stabilized MBs where the inert gas (e.g., sulfur hexafluoride (SF6), etc.)…”

“…31,32 Hence, substantial efforts have been made to develop improved ultrasonic imaging methods, including ultrasensitive, quantitative, high-resolution and high-frequency ultrasonic imaging, as well as 4D functional ultrasonic imaging, aimed at improving the accuracy of tumor diagnosis. 109–117 By combination with other image analysis techniques ( e.g. , artificial intelligence (AI) and deep learning), professionals can reduce interference from false positive signals and effectively determine the boundary of tumor tissues.…”

“…, liver, kidney, uterus, prostate, thyroid, and mammary gland), lymph node metastasis, diverse inflammations, as well as acute kidney injury. 108–115 Compared to GSUS and DUS imaging modalities, the existence of ultrasonic contrast agents in the CEUS imaging method can improve the resolution and sensitivity of ultrasonic diagnosis by enhancing echo-backscatter by the contrast media. 106,126 One kind of commercial ultrasonic contrast agents, e.g.…”