[The histological change, MRI manifestation and neurological deficiency of old spinal cord injury].

The L1 spinal cord of 22 dogs were injured by modified Allen's method. During the interval of 50-100 days after injury, MR imaging were performed and the specimens of the injured spinal cord were taken out immediately for histological examination. T1 weighted images were used to observe changes of spinal cord signals. In 7 cases with cavity formation in the central part of the injured spinal cord was found histologically, there was small cavity in the spinal cord signal on MRI. In 12 cases with necrosis and softening in central area of the spinal cord, the T1 weighted image showed hypointensity in central part of spinal cord signal, and in 3 cases with necrosis, degeneration and glial replacement histologically, the MR image showed unhomogeneous and slight hyointensity signal. These entities suggested that the MRI appearances of spinal cord injury represented the histological changes of the spinal cord. Clinically, the MRI manifestation of 76 cases of old spinal cord injury were closely related to their neurologic deficiency. Cases of transection signal of spinal cord were excluded. There were six types of MRI appearances. In 40 cases of complete paraplegia, the MRI appearances were enlarged hypointensity signal in 16 hypointensity signal in 4, atrophy of the spinal cord in 13, large cavity in 3 and unhomogeneous with compression in 1. After treatment, there were no recovery in all cases. 36 cases of incomplete paraplegia their MRI showed normal signal but compressed in 16, all had good recovery after treatment. Unhomogenous signal with slight hypointensity was found in 11, they one frankle degree recovery after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)