1H-MR spectroscopy of dog's brain contusion and laceration

Objective: To investigate proton magnetic resonance spectroscopy (1H-MRS) findings and value on dog's brain contusion and laceration. Methods: Models of focal brain contusion and laceration in 10 dogs were established through hitting on the right frontal-parietal lobe with a freely drop of 200g weight at 1.3 m height. Serial examinations (1 h, 24 h, 72 h, 5 day, 8 day and 14 day after trauma) were performed with conventional MRI and 1H-MRS. NAA/Cr, Cho/Cr and NAA/Cho rates were analyzed with GE system 1.5 T scanner and relative software. After examination, all dogs were executed to death. Pathological study was performed at local brain contusion. Results: 1 h and 24 h-post trauma, NAA/Cr, Cho/Cr, NAA/Cho were significantly reduced (NAA/Cr 0.843±0.214, 0.862±0.204, contralateral ones 1.069±0.284, 1.048±0.232, t=-7.227, -6.718, Cho/Cr 1.181±0.224, 1.243±0.134, contralateral 1.415±0.305, 1.455±0.159, t=-4.332, -4.489, NAA/Cho 0.701±0.147, 0.536±0.136, contralateral 0.832±0.245, 0.613±0.165, t=-2.652, -2.665. P<0.05). Microscopy showed focal petechial hemorrhage and necrosis, neuron loss, neuraxonal swelling and small glial cell slightly hyperplasia. Five day post trauma, Cho/Cr was significantly elevated in comparison with contralateral ones (1.517±0.197, contralateral 1.387±0.214, t=3.758 P<0.05). Pathologically, inflammatory was obvious, peri-angiitis, granula tissue and fibrosis were seen. 8-14 day later, NAA/Cr was not significantly reduced (0.895±0.105, 0.875±0.153, contralateral 0.989±0.169, 0.990±0.173, t=-2.909, -2.471. P>0.05), Cho/Cr was significantly increased (1.457±0.168, 1.572±0.374, contralateral 1.334±0.174, 1.366±0.352, t=7.312, 3.201. P<0.05). Inflammatory and glial hyperplasia was more significant, granuloma were seen. Lipid and Lac peak were not seen at all stages. Conclusion: MRS could be a methods to monitor neuron injury and repair, and dynamically to detect the metabolic changes of brain contusion and laceration, reflecting injury severity and provide theory data for early treatment and predicting long-term outcome after trauma. (authors)