[Contrast-enhanced Ultrasonography and Color Doppler Ultrasonography for Dynamic Assessment of Intracranial Changes in Early MCAO Rats Models].

OBJECTIVE: To assess the value of contrast-enhanced ultrasound (CEUS) and color Doppler ultrasound (DUS) on hemodynamic changes and cerebral perfusion quantitative analyses in Sprague-Dawley (SD) rats with focal permanent ischemic stroke. METHODS: Sixteen SD rats with thin skulls were subjected to establish middle cerebral artery occlusion (MCAO) model. CEUS images were performed before modeling (T 0), immediately after modeling (5-15 min after modeling, T 1), 3 h after modeling (T 2), followed by the measurement of bilateral middle cerebral artery (MCA), anterior cerebral artery (ACA), posterior cerebral artery (PCA) using DUS. The peak systolic velocity (PSV), end-diastolic velocity (EDV) and mean velocity (MV) of these arteries were obtained. The brain time-intensity curve was taken as interest region of the whole right brain, and the quantitative parameters of CEUS were obtained, including peak intensity (PI), area under the curve ( AUC), wash in slope (WIS), time to peak (TTP), rise time (RT) and time from peak to one half (TPH). The modified neurological deficit score (mNSS) of the rats was performed 3 h after the modeling, and the data of the rats with a score of 9-11 were statistically analyzed. RESULTS: A total of 12 rats were successfully modeled and completed with mNSS score 9-11. No blood flow signals were observed on the right MCA and ACA in the 12 rats at T 1 and T 2. From T 0 to T 1, PI, AUC and WIS of the right hemisphere decreased sharply with TTP and RT significantly prolonged, and the differences were statistically significant. However, there was no significant difference in hemodynamic parameters at that period of time. From T 1 to T 2, there were no significant changes in CEUS quantitative parameters (except AUCand TPH), while PSV, EDV, MV of LMCA and bilateral PCA showed significant acceleration, and the differences were statistically significant. CONCLUSION: CEUS and DUS can reveal the intracranial hemodynamics and brain tissue perfusion trends of MCAO rats, which could be new methods in assessment of ischemic stroke model at multiple time points.

[Application of Multimodal Transcranial Ultrasound in SD Rats of Cerebral Ischemic Model at Super Early Stage].

OBJECTIVE: To determine the value of applying multimodal ultrasound (mUS) in SD rats of cerebral ischemic model at super early stage (5-15 min after modeling). METHODS: Fifteen focal cerebral ischemic models were established in SD rats with thinning skulls using the suture method. Gray-scale ultrasound, contrast-enhanced ultrasound, and enhanced color Doppler (CECDUS) were performed before and immediately after the modeling to observe the location of the in-cranial suture, perfusion of the right hemisphere, and color flow signal of the middle cerebral artery and the anterior cerebral artery, respectively.A modified neurological deficit score (mNSS) and 2, 3, 5-triphenyltetrazolium chloride (TTC) stains were obtained three hours later to confirm the successful modeling as the gold standard. The positive rate detected by mUS was compared with the gold standard using McNemar tests. RESULTS: One rat died and 14 rats completed the experiment.mUS imaging detected 71% (10/14) positive signals, no significant difference compared with the gold standard (64%, 9/14) ( P>0.05). A hyperechoic double-line at the bottom of the right brain and focal hypoperfused areas in the right hemisphere were observed by gray scale ultrasound and contrast-enhanced ultrasound in the successfully modeled rats, respectively. The CECDUS found no blood flow in the anterior and middle cerebral arteries. Time intensity curve (TIC) analyses indicated significant changes in peak intensity (PI), area under the curve (AUC), wash in slope (WIS), and time to peak (TTP) after successful modeling. CONCLUSION: Multimodal ultrasound can assess modeling success quickly and accurately immediately after the establishment of ischemic model of SD rats.