Experimental Studies Of Transcranial Ultrasonography And Cerebral Parenchyma Heamorrhage Enhanced By A Newly Developed Lipid-coated Ultrasound Contrast Agent

Background: The new development of ultrasound contrast agent (UCA) and corresponding techniques had made it possible to explore cerebral vessels and parenchyma, although much of them are still unknown. Currently, there is no commercial available contrast agent for 2-D parenchymal enhancement. Safe, effective and reproducible UCA is needed. Myocardial contrast echocardiography is able to assess the myocardial perfusion. However, the imaging abilities of UCA in cerebral circulation or tissues heamorrage are yet to understand.Objective: This study is designed to evaluate the abilities of contrast ultrasonography to image the normal cerebral parenchyma and cerebral heamorrhage in animal models. The images were analyzed quantitatively and separately by acoustic densitometry (AD) and video intensity. A new-developed ultrasound contrast agent "ZHIFUXIAN" was used in the study.Methods: 10 mongrels, male, weighted from 10.5 to 13.5 kg were used. The animal model of cerebral parenchyma heamorrhage was made by injecting blood into brain parenchyma guided by ultrasound. Contrast transcranial 2-D and color flow imaging were performed in 3 normal dogs and 7 cerebral heamorrage dogs. The imaging modalities used here were intermittent harmonic imaging and contrast real-time harmonic imaging after bolus injection of UCA. The enhancement of cerebral vessels and parenchyma was further assessed by acoustic densitometry (AD) and video intensity. All data were presented in mean ± SD and analyzed by paired t test.Results: Significant contrast-enhanced imaging was observed in all 3 normal dogs and 7 brain parenchyma heamorrhage dogs. The peak intensity time was found from the 30th to the 40th second after bolus injection and the effective visual contrast could persist 3 minutes at thalamus and 5 minutes at cortex and white matter. Statistical significances (p <0.01) were found were significantly different in peak intensity, area under curve pre and post-contrast at thalamus, cortex and white matter. In 7 dogs with brain heamorrhage, the dimension and margin of the brain haematoms were clearly distinguished andwell-corresponded on sonography, computer tomography and pathology. The size of haematoms measured by ultrasound and CT was consistent with pathology (p>0.05). The gray scale enhancement of cerebral parenchyma was significant after contrast (p <0.01) but different in haematom, haematom borderline, and normal cerebral parenchyma (p<0.01). The haematom showed no significant diffierence before and after contrast (p>0.05). The gray scale enhancement at haematom surroundings area was greater than normal cerebral parenchyma (p <0.01) . The cerebral vessels of cortex were showed clearly by transcranial contrast-enhanced sonography and color flow imaging lasted at least 30 minutes.Conclusion: Contrast ultrasonography is able to enhance the images of cerebral vessels and parenchyma with a low dose bolus of a new ultrasound contrast agent "ZHIFUXIAN". The acoustic densitometry (AD) and video intensity can identify the cerebral perfusion difference qualitatively and quantitatively. Nevertheless, this technique could recognize and delineate haematoma from normal cerebral parenchyma and could be helpful in diagnosis of cerebral hemorrhage. Contrast enhanced transcranial sonography is a promising new non-invasive technique for brain and cerebral vessel disease.