QUALITATIVE DIAGNOSIS OF PCT AND BEAM IN ACUTE CEREBRAL INFARCTION

Yi Man, KuiKui Zheng

Department of Radiology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou City 325000, China

 Objective: To explore the qualitative diagnosis of perfusion computed tomography (PCT) and brain electrical activity mapping (BEAM) in acute cerebral infarction, the quantitative evaluation of the severity of the lesion, and the application value of in the judg- ment of infarct area and ischemic penumbra (IP), so as to guide the clinical treatment.

Methods: 41 patients with acute cerebral infarction within 24 hours of onset in hospitalized in First Affiliated Hospital of Wen- zhou Medical University from January 2017 to December 2017 were selected. All patients were examined by routine CT, PCT and BEAM. Routine CT examination was based on OM line, scanning upward, and 5mm thickness, scanning 20 levels in total. After rou- tine CT scan, 80 reconstructed images of the basal ganglia and its upper or lower layers were processed with a special CT perfusion software package. The perfusion images were obtained, the parameters of the brain’s sensory interested areas were measured, and the images were analyzed quantitatively. The sensory interested areas were animated by hand, either on one side or in the form of mirror image in the corresponding area. BEAM was performed with a randomly worn electrode cap. 21 electrodes were placed according to the international 10/20 system, and the earlobes were used as reference electrodes. The quiet closed-eye EEG was recorded for 3 minutes. Fast Fourier transform (FFT) was conducted with 30 seconds non-interference EEG input into the computer to display the frequency band power distribution map. The band power distribution map was analyzed to observe the characteristics of routine CT, PCT and BEAM in acute stage of cerebral infarction, calculate their positive rates and make statistical analysis.

Results: Firstly, within 24 hours after the onset of cerebral infarction, the positive rate of routine CT was 34.1%, PCT was 87.8%, and BEAM was 90.2%. Statistical analysis showed that the positive rates of routine CT and PCT, routine CT and BEAM were significantly different (P<0.01), and there was no significant difference between BEAM and PCT (P=1). Secondly, BEAM could accurately determine the lesion side, but the positioning accuracy was worse than that of PCT, and PCT positioning and lateral positioning were very accurate. Parameters cerebral blood flow (CBF), cerebral blood volume (CBV) and time to peak (TP) values of PCT were significantly different be- tween the central and peripheral lesions (P<0.01), while time to start (TS) and peak enhancement (PE) values were significantly different (P<0.05). CBF values in the central and peripheral lesions were 6.23±2.71 mL/min/100g) and 19.15±4.68 mL/min/100g), respectively. CBF values between the mean lesion area and the corresponding contralateral areas were significantly different (P<0.01), and CBV and TP values were also different (P<0.05), but there were no significant differences in TS and PE values (P≥0.05). The parameters of PCT were significantly different among the mild, moderate and severe groups (P<0.01). There were significant differences in CBF, CBV and TP among the three groups. There were significant differences in TS and PE between the mild, moderate and severe groups, but there were no significant differences between the moderate and severe groups. There was a positive correlation between CBF and CBV in PCT, and a negative correlation between CBF and TP. There was a significant difference between the average power of BEAM δ band power diagram in abnormal leads in the lesion area and the average power of the corresponding area in the opposite side.

Conclusion: PCT can improve the diagnostic rate of acute cerebral infarction, visualize and quantify the severity of the disease, and discover hemodynamic changes beyond the infarct focus. BEAM can diagnose acute cerebral infarction early, and can accurately determine its side, showing IP with abnormal functions. The localization of BEAM is not as accurate as PCT, but because of the limitation of perfusion layer, the range of PCT is not as wide as BEAM. The combination of BEAM and PCT can improve the diagnosis rate and accuracy.