Perfusion computed tomography evaluation of partial hepatic ischemia reperfusion in a rabbit model

Perfusion imaging with 320-slice spiral computed tomography and color-coded digital subtraction angiography for assessing acute skeletal muscle ischemia-reperfusion injury in a rabbit model

BACKGROUND

In recent years, skeletal muscle-related ischemia-reperfusion injury (IRI) has become more common. IRI can lead to severe limb injuries, multiple organ failure, and even death in some cases. However, there is still a lack of rapid and sensitive detection methods for IRI in skeletal muscle. This study aims to explore the value of computed tomography perfusion imaging (CTPI) and color-coded digital subtraction angiography (DSA) in assessing acute IRI of skeletal muscle in a rabbit model.

METHODS

Fifty New Zealand white rabbits were randomly assigned to the ischemia-reperfusion (IR) group (n = 40) or sham group (n = 10). After 3 h of surgically-induced hindlimb ischemia, the IR group underwent reperfusion and CTPI and color-coded DSA were taken to assess the skeletal muscle at 0, 6, 12, or 24 h post-reperfusion. The data from CTPI and DSA in the right and left hindlimbs, blood flow (AF-R/L), blood volume (BV-R/L), contrast clearance rate (C-R/L) and the maximum contrast enhancement values (peak-R/L) were obtained. Serum superoxide dismutase (SOD), creatine kinase (CK), lactic dehydrogenase (LDH) and malondialdehyde (MDA) were measured. The statistical correlation between the above parameters (CTPI, color-coded DSA, and biochemical markers) was analyzed.

RESULTS

The mean value of AF-R/L, BV-R/L, C-R/L and peak-R/L decreased linearly from 1.07 ± 0.08 to 0.75 ± 0.11, 1.03 ± 0.06 to 0.85 ± 0.14, 0.93 ± 0.15 to 0.71 ± 0.18, and 1.07 ± 0.01 to 0.47 ± 0.04, respectively. The correlation coefficients between AF-R/L and SOD, CK, LDH and MDA were 0.57, - 0.44, - 0.60, and - 0.62, respectively (p < 0.001). The correlation coefficients between Peak-R/L and SOD, CK, LDH, MDA were 0.59, 0.68, 0.71 and 0.66, respectively (p < 0.001). The correlation coefficient between AF-R/L and Peak-R/L was 0.70 (p < 0.001).

CONCLUSION

Both CTPI and color-coded DSA could dynamically assess skeletal muscle IRI in rabbits.

Comparison of the DWI and Gd-EOB-DTPA-enhanced MRI on assessing the hepatic ischemia and reperfusion injury after partial hepatectomy

OBJECTIVE

To compare two different imaging media, diffusion weighted imaging (DWI) with apparent diffusion coefficient (ADC) and Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) with perfusion parameters K^trans, K^ep, and relative contrast enhancement index (RCEI), in assessing the liver function via ischemia/perfusion injury (IRI) + partial hepatectomy rat model.

METHODS

Rats underwent 0, 30 and 60min of ischemia/reperfusion with 30% of hepatectomy before subjected to Gd-EOB-DTPA-enhanced MRI in addition to ^99mTc-GSA scintigraphy. For ^99mTc-GSA scintigraphy test, the receptor index LHL15, modified receptor index and the blood clearance index HH15 were recorded. Apparent diffusion coefficient (ADC) was evaluated by using both mono- and bi-exponential models, and perfusion parameters K^trans, K^ep, and RCEI were measured. Liver function is tested by measuring activity of serum ALT, AST and PT. Histological analysis was performed by H&E and Ki-67 staining.

RESULTS

^99mTc-GSA dynamic imaging analysis demonstrated that LHL15 was increased and HH15 was decreased as the extension of ischemia/reperfusion time. ADC value estimated by MRI was significantly increased (P<0.05) in 30min IRI group compared with 0min and 60min IRI groups, respectively. K^trans value was gradually and significantly decreased (P<0.05) as the extension of IRI time, but there was no significant difference (P>0.05) in K^ep value between at 30min and 60min IRI, and RCEI value was significantly higher (P<0.05) in 30min IR compared with 0min and 60min IRI group. Serum level of ALT, AST and PT were gradually and significantly (P<0.05) increased as the extension of IRI time. Histological analysis showed that there was a remarkable difference between 30min and 60min IRI, as protein expression of Ki-67 was significantly higher (P<0.05) in 30min IRI group.

CONCLUSION

Fast ADC bi-exponential model in DWI and RCEI in Gd-EOB-DTPA-enhanced MRI showed the good correlation in assessment of liver function after partial hepatectomy, showing consistency with our histological findings. The K^trans in Gd-EOB-DTPA-enhanced MRI could be a potent parameter for assessing the early ischemic injury, but not the severity of the hepatic injury, in accordance with the correlation with our biochemical findings.