Diagnostic Value Of Magnetic Suseceptibility-Weighted Imaging In Diffuse Axonal Injury

Background:To study the diagnostic value of Susceptibility Weighted Imaging (SWI) in diffuse axonal injury (DAI) and the relationship between SWI and clinical prognosis.Methods:Fifty patients (35males and15females) with DA1were included in this study. Routine sequences (T1WI, T2WI, T2WI-FLAIR and DWI) and SW1were performed on a Siemens Essenza1.5T MRI scanner. The cerebral injuries were caused by traffic accident in30cases, fall in10cases, heavy pound in5case and beating in5case. There were23cases whose Glasgow coma Scale (GCS) ranged from3to5,9cases from6to8and18from9to12. The interval time between injury and examination was between3hours to10day, The number and volume of lesions observed in SWI and routine sequence were compared.Resul ts:Routine MRI scan found a total of436lesions, while SWI sequence detected966lesions. The number of the lesions found in SWI sequence was greater than that of conventional MRI (μ=-10.42, p=0.000). DAI lesions showed high signal or a slightly lower signal on T1WI and high or low signal on T2WI. DAI lesions showed high signal on T2WI-FLAIR and iso-intense or low signal in the central part of some lesions. Punctuate or sheet lesions can be seen in conventional MRI and the boundaries of the majority of lesions were not clear. The lesions were punctuate, beaded, patchy and cord-like significantly lower signal with various sizes on SWI. Some lesions merged into plate signal (Lesion diameter<2.0cm). Distribution of lesions was multifocal with clear boundary. Lesions were punctuate or linear mostly in the corticomedullary junction, beeded mostly in white matter and cerebellar and patchy mostly in basal ganglia, corpus callosum and brain stem. The total volume of the lesions measured in conventional MRI and SW1were46109.2mm3and108832.3mm3, respectively. The total volume measured in SWI was bigger than that in routine MRI(t=-8.418, p=0.000). The number and volume of all lesions were negatively correlated with GCS (r=-0.802,p<0.01and r=-0.767, p<0.01).Conelusion:SWI sequence can found more bleeding lesions than the routine MRI sequences. In particular, SWI has advantages in displaying small bleeding lesions with needle-like. The total volume measured in SWI was bigger than that in routine MR. At the same time, SWI can show the location and extent of lesions clearly. The number and the volume of the lesions are closely related to GCS. Thus it can be said that SWI provide an important imaging basis for diagnosing DAI and evaluating the prognosis of patients.