Dynamic assessment of acute blunt cerebral contusions and lacerations with CT perfusion: an experimental study

Objective: To explore the dynamic changes of blood perfusion in traumatic cerebral contusion and laceration of experimental model. Methods: Impact-acceleration head traumatic cerebral contusion and laceration models of 40 rabbits were established. CTP was made for all animals at 1, 3, 6, 12, 24, 48 and 72 h after head injury. The original images were transferred to workstation for postprocessing. Cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) of central area, peripheral area of contusion and laceration, and their mirror areas were measured on the section in which lesions were in their maximal area. The CTP parameters among different areas were compared with paired samples t test. The evolvement of CBF, CBV and MTT of cerebral contusion and laceration areas were recorded as well. Then, the histological abnormalities of central and peripheral areas were observed separately by referring to corresponding CTP maps. Results: Experimental models were successfully made in 35 rabbits. Abnormal signal intensity was detected on their T2WI and DWI images, which was consistent with brain contusion. For CTP parameters: (1) The CBF of central area of the lesions decreased markedly after trauma and reached its nadir at 12 h. Then the CBF of central area rose slowly from 24 h. The value of CBF of the central area at 1, 3, 6, 12, 24 and 72 h were (27.58±18.70), (20.64±6.50), (23.38± 7.53), (22.14±10.25), (25.08±11.01), (43.08±18.33) and (54.79± 14.63) ml·min-1·100 g-1 respectively. Whereas the CBF value of the corresponding mirror areas were (62.28±25.46), (60.67±16.19), (67.00±21.34), (74.46±20.11), (66.73±11.68), (81.63± 10.99) and 86.16±10.57) ml·min-1·100 g-1 respectively. There was significant difference of CBF between the central and the mirror areas (t=4.41, 5.57, 5.47, 6.02, 6.44, 4.81, 10.60 respectively, P<0.05). The CBF value of the peripheral area decreased slightly, which reached the lowest level at 1 h and 3 h, after that it increased slowly. There was no significant difference between the peripheral areas and their corresponding mirror areas (P>0.05). (2) The CBV of central area of the lesions also decreased obviously after trauma and reached its nadir at 12 h. Then the CBV of central area rose slowly from 24 h. The value of CBV of the central area at 1, 3, 6, 12, 24 and 72 h were (1.74±0.46), (2.22±0.86), (2.26±0.44), (1.15±0.22), (2.67±0.77), (2.68±0.72) and (2.86±0.65) mL/100 g respectively. The CBV value of the corresponding mirror areas were (7.27±5.29), (6.18±1.82), (6.93±1.86), (6.66±2.75), (8.48±2.34), (8.56±2.38) and (8.83±1.57) ml/100 g respectively. There was significant difference of CBV between the central and the mirror areas (t=3.09, 5.38, 6.25, 4.80, 7.82, 6.36 and 8.51 respectively, P<0.05). The CBV value of the peripheral area decreased slightly, which reached the lowest level at 1 h and 3 h, after that it increased slowly. There was no significant difference between the CBV of peripheral areas and their corresponding mirror areas (P>0.05). The increase trend of CBV of peripheral areas was similar to those of their corresponding mirror areas. (3) The value of MTT of the central area increased obviously from 1 to 3 hour, and decreased markedly after that, and reached its platform at 12 h. The MTT of the central area at 1, 3, 6, 12, 24 and 72 h were (4.88±1.37), (5.09± 1.21), (4.49±1.33), (3.44±0.46), (3.58±0.42), (3.51±0.73) and(3.30±0.27) s respectively. Whereas MTF of the corresponding mirror area were (2.03±0.07), (2.03±0.04), (2.04±0.07), (2.00±0.55), (2.07±0.20), (2.06±0.06) and (2.02±0.02) s respectively. There was significant difference between the value of MTT of the central area and the corresponding mirror area (t=5.87, 5.95, 4.43, 7.74, 9.02, 4.73 and 4.76 respectively, P<0.05). MTT of the peripheral area were increased relative to the corresponding mirror area before 24 h and had a trend of decrease from 1 to 24 h. There was no significant difference between the values of MTT of peripheral area and the corresponding mirror area at 24 and 72 h. No change was found for the MTT of mirror area at various time points. More prominent pathological findings, including speckle hemorrhage, necrosis, edema, enlargement of peri-vascular space were observed in the central area than in the peripheral area. Conclusions: As a convenient technique, CTP is a sensitive tool for detecting and monitoring the hemodynamic changes of cerebral contusion and laceration. The perfusion of cerebral contusion and laceration shows some specific temporal change in traumatic model of rabbits. The changes of CTP parameters of the central area were more remarkable. (authors)