Diffusion Tensor MRI In Patients With Arteriosclerosis Cerebral White Matter Disease

Purpose:To investigate the characteristics of arteriosclerosis cerebral white matter disease on diffusion tensor MRI.Material and methods:100 patients and 20 healthy subjects were examined by conventional MRI and diffusion tensor MRI.①Fraction anisotropy(FA), apparent diffusion coefficient(ADC), axial diffusivity(λ‖)and radial diffusivity(λ⊥) were measured and calculated in the lesions of posterior horn of periventricular (PHPV), anterior horn of periventricular (AHPV)and centrum semiovale(CS) in mild(n=55), moderate(n=28) and severe(n=17) arteriosclerosis cerebral white matter disease and the corresponding normal white matter in the normal group(n=20). FA, ADC,λ‖andλ⊥of the lesions and the corresponding normal white matter in the normal group were compared statistically.②FA. ADC,λ‖andλ⊥were measured and calculated in the lesions, the normal appearing white matter (NAWM) of PHPV, AHPV and CS, then compared with the normal group.③FA, ADC,λ‖andλ⊥were measured and calculated in the three types including normal(n=20), impaired(n=83), fiber tracing interrupt(n=17), then compared with each other.Results:On DTI, lesions and NAWM present to low signal on FA map.①Compared with 20 healthy subjects, we found decreased FA and increasedλ⊥in the lesions of mild(n=55), moderate(n=28) and severe(n=17) arteriosclerosis cerebral white matter disease (p<0.05), With the progression of the disease, FA decreased more andλ⊥increased more than before, while ADC andλ‖is increased slightly (p>0.05).②We found decreased FA and increasedλ⊥in both lesions and NAWM of arteriosclerosis cerebral white matter disease compared with 20 healthy subjects (p<0.05), while ADC andλ‖is increased slightly (p>0.05). We also found decreased FA and increasedλ⊥in lesions than NAWM (p<0.05), while ADC andλ⊥is increased slightly (p>0.05).③We found decreased FA and increasedλ⊥in the impaired white matter than healthy subjects (p<0.05), while ADC andλis increased slightly (p>0.05). We found decreased FA,increased ADC,λ‖andλ⊥in fiber tracing interrupted white matter than healthy subjects (p<0.05). We found decreased FA.increased ADC,λ‖andλ⊥in fiber tracing interrupted white matter than impaired white matter (p<0.05).Conclusion:White matter in the brain can be well demonstrated on FA maps. Using DTI. anisotropic feature can be quantified. Range of lesions is larger in DTI than in conventional MRI. DTI can find occult lesions, and these lesions can not be found in conventional MRI. DTI reflects the changes of white matter fiber. Our findings of decreased FA and increased radial diffusivity, provide preliminary evidence for abnormal demyelination, while lesions of interrupted fiber demonstrate both demyelination and fiber axons tracing interrupted. DTI can distinguish different pathological changes from high signal intensity in T2WI and T2FLAIR. DTI is far more sensitive than MRI in patients.