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Objective To discuss the prognostic evaluation of magnetic resonance diffusion tensor imaging (DTI) in term neonates with mild and severe asphyxia.Methods Eleven neonates with mild asphyxia,14 neonates with severe asphyxia and 10 control neonates were studied.All the neonates were examined by conventional magnetic resonance imaging(MRI) and DTI.Fraction anisotropy (FA) values,apparent diffusion coefficient (ADC) values,voxel numbers and fiber numbers were calculated in seven regions of interest(ROI) and compared among the 3 groups.The correlation between FA values and neonatal behavioral neurological assessment (NBNA) scores were analyzed.Results (1) FA values in the left and the right thalamus were 0.54 ± 0.08 and 0.56 ± 0.15 in control group,0.45 ±0.03 and 0.44 ± 0.10 in mild group,and 0.21 ± 0.11 and 0.25 ± 0.13,respectively in severe group.FA values in posterior limbs of internal capsule were 0.49 ± 0.09 and 0.48 ± 0.08 in control group,0.37 ± 0.08 and 0.38 ± 0.03 in mild group,and 0.20 ± 0.04,0.19 ± 0.13 in severe group;FA values in thalamus and posterior limbs of internal capsule had statistical differences among the 3 groups (F =9.12,9.11,8.18,8.55,all P ＜ 0.05).Voxel numbers in the left and the right superior longitudinal fasciculus were 1 094 ± 112 and 1 123 ± 113 in control group,986 ± 111 and 1 009 ± 144 in mild group,450 ± 116 and 671 ± 126 in severe group.Voxel numbers in anterior limbs of internal capsule were 947 ± 104 and 1 237 ± 184 in control group,854 ± 118 and 799 ± 114 in mild group,324 ± 110 and 311 ± 126 in severe group.Voxel numbers in posterior limbs of internal capsule were 2 047 ± 129 and 2 137 ± 238 in control group,1 843 ± 233 and 1 753 ± 247 in mild group,867 ± 118 and 999 ± 167 in severe group.Voxel numbers in superior longitudinal fasciculus,anterior and posterior limbs of internal capsule had statistical differences among the 3 groups (F =10.11,9.45,7.33,8.45,12.65,11.23,all P ＜ 0.05);Fiber numbers in the left and the right cingulate gyrus were 245 ±72 and 405 ±94 in control group,225 ±52 and 365 ± 114 in mild group,145 ±62 and 185 ±84 in severe group.Fiber numbers in inferior front-occipital fasciculus were 56 ± 19 and 212 ± 33 in control group,49 ±22 and 197 ± 33 in mild group,33 ± 12 and 156 ± 39 in severe group.Fiber numbers in posterior limbs of internal capsule were 284 ± 112 and 988 ± 233 in control group,234 ± 67 and 678 ± 234 in mild group,114 ± 67 and 188 ± 84 in severe group.Fiber numbers in cingulate gyrus,inferior front-occipital fasciculus and posterior limbs of internal capsule had statistical differences among the 3 groups (F =3.11,3.45,9.88,9.12,7.45,8.88,all P ＜ 0.05).(2) The correlation between FA value and NBNA scores was analyzed:the correlation coefficient in posterior limbs of internal capsule was 0.666 which was higher than those of the other areas.The area under the ROC curve of FA values in anterior limbs of internal capsule was 0.816 (P =0.005),used NBNA scores ≥ 35 as a good outcome.FA values (≥ 0.375) in the posterior limbs of the internal capsules predicted a good outcome and the corresponding sensitivity and specificity was 73.1％ and 77.8％,respectively.Conclusion In some ROIs,FA values,voxel numbers,and fiber numbers can quantitatively reflect the degree of white matter injury in neonates with asphyxia.Furthermore,the FA values in the posterior limbs of the internal capsules are closely correlated with NBNA scores,so it has more important clinical significance,and can accurately and objectively assess the prognosis in neonates with asphyxia.
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Objective To discuss the prognostic evaluation of magnetic resonance diffusion tensor imaging (DTI) in term neonates with mild and severe asphyxia.Methods Eleven neonates with mild asphyxia,14 neonates with severe asphyxia and 10 control neonates were studied.All the neonates were examined by conventional magnetic resonance imaging(MRI) and DTI.Fraction anisotropy (FA) values,apparent diffusion coefficient (ADC) values,voxel numbers and fiber numbers were calculated in seven regions of interest(ROI) and compared among the 3 groups.The correlation between FA values and neonatal behavioral neurological assessment (NBNA) scores were analyzed.Results (1) FA values in the left and the right thalamus were 0.54 ± 0.08 and 0.56 ± 0.15 in control group,0.45 ±0.03 and 0.44 ± 0.10 in mild group,and 0.21 ± 0.11 and 0.25 ± 0.13,respectively in severe group.FA values in posterior limbs of internal capsule were 0.49 ± 0.09 and 0.48 ± 0.08 in control group,0.37 ± 0.08 and 0.38 ± 0.03 in mild group,and 0.20 ± 0.04,0.19 ± 0.13 in severe group;FA values in thalamus and posterior limbs of internal capsule had statistical differences among the 3 groups (F =9.12,9.11,8.18,8.55,all P ＜ 0.05).Voxel numbers in the left and the right superior longitudinal fasciculus were 1 094 ± 112 and 1 123 ± 113 in control group,986 ± 111 and 1 009 ± 144 in mild group,450 ± 116 and 671 ± 126 in severe group.Voxel numbers in anterior limbs of internal capsule were 947 ± 104 and 1 237 ± 184 in control group,854 ± 118 and 799 ± 114 in mild group,324 ± 110 and 311 ± 126 in severe group.Voxel numbers in posterior limbs of internal capsule were 2 047 ± 129 and 2 137 ± 238 in control group,1 843 ± 233 and 1 753 ± 247 in mild group,867 ± 118 and 999 ± 167 in severe group.Voxel numbers in superior longitudinal fasciculus,anterior and posterior limbs of internal capsule had statistical differences among the 3 groups (F =10.11,9.45,7.33,8.45,12.65,11.23,all P ＜ 0.05);Fiber numbers in the left and the right cingulate gyrus were 245 ±72 and 405 ±94 in control group,225 ±52 and 365 ± 114 in mild group,145 ±62 and 185 ±84 in severe group.Fiber numbers in inferior front-occipital fasciculus were 56 ± 19 and 212 ± 33 in control group,49 ±22 and 197 ± 33 in mild group,33 ± 12 and 156 ± 39 in severe group.Fiber numbers in posterior limbs of internal capsule were 284 ± 112 and 988 ± 233 in control group,234 ± 67 and 678 ± 234 in mild group,114 ± 67 and 188 ± 84 in severe group.Fiber numbers in cingulate gyrus,inferior front-occipital fasciculus and posterior limbs of internal capsule had statistical differences among the 3 groups (F =3.11,3.45,9.88,9.12,7.45,8.88,all P ＜ 0.05).(2) The correlation between FA value and NBNA scores was analyzed:the correlation coefficient in posterior limbs of internal capsule was 0.666 which was higher than those of the other areas.The area under the ROC curve of FA values in anterior limbs of internal capsule was 0.816 (P =0.005),used NBNA scores ≥ 35 as a good outcome.FA values (≥ 0.375) in the posterior limbs of the internal capsules predicted a good outcome and the corresponding sensitivity and specificity was 73.1％ and 77.8％,respectively.Conclusion In some ROIs,FA values,voxel numbers,and fiber numbers can quantitatively reflect the degree of white matter injury in neonates with asphyxia.Furthermore,the FA values in the posterior limbs of the internal capsules are closely correlated with NBNA scores,so it has more important clinical significance,and can accurately and objectively assess the prognosis in neonates with asphyxia.
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ObjectiveTo detect the fiber structure and volume differences in frontal lobe between patients with amnestic mild cognitive impairment (aMCI) and normal control.MethodsT1 -weighted magnetic resonance imaging and diffusion tensor imaging were obtained in 28 aMCI patients and 25 normal controls.Volumes,fiber fractional anisotropy (FA),fiber apparent diffusion coefficient (ADC),fiber number,and average fiber length of frontal lobe in the two groups were measured.ResultsVolumes of left frontal lobe ( ( 337.35 ± 20.45 ) cm3 ) in aMCI group were smaller than control ( (358.54 ± 27.26) cm3 ) ( t =- 3.223,P =0.002 ).Numbers of short range fiber in left frontal lobe ( 16985 ± 892) were significantly increased relative to control ( 16387 ±752) ; while numbers of long range fiber (3214 ± 185 ) were reduced compared with control (3425 ± 277 ),and ADC values increased ( t =2.621,P =0.012; t =-3.714,P =0.001 ; t =17.595,P=0.000).In aM CI group,numbers of long range fiber in right frontal lobe were reduced (2895 ± 343 vs.3451 -± 230,t =- 7.011,P =0.000),and ADC values were increased ( t =4.443,P =0.000).In aMCI group,numbers of long range fiber in left frontal lobe were positively correlated with scores of mini-mental state examination ( MMSE ) ( r =0.457,P =0.015 ),while ADC values of long range fiber in left frontal lobe were negatively correlated with scores of MMSE ( r=-0.415,P=0.028).ConclusionThe structure and fiber connectivity are affected in aMCI patients and the lesion of connectivity in left frontal lobe are related to the severity of symptom.
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Diffusion tensor imaging (DTI) and fiber tracking (FT) may show structural information about white matter fiber. With development of technology, the applications of the DTI and FT are widely used in spinal cord. DTI and FT are more sensitive than traditional MRI on detecting spinal cord lesions, able to provide more evidence for the diagnosis and differential diagnosis before treatment, as well as the evaluation for the prognosis.
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PURPOSE: Magnetic resonance diffusion tensor imaging-based three-dimensional fiber tractography (DTI-FT) is a new method which demonstrates the orientation and integrity of white matter fibers in vivo. However, clinical application on children with cerebral palsy is still under investigation. We present various abnormal patterns of DTI-FT findings and accordance rate with clinical findings in children with hemiplegic cerebral palsy, to recognize the usefulness of DTI-FT. METHODS: The thirteen children with hemiplegic cerebral palsy evaluated at Yeungnam University hospital from March, 2003 to August, 2007 were enrolled in this study and underwent magnetic resonance DTI-FT of the corticospinal tracts. Two regions of interest (ROI) were applied and the termination criteria were fractional anisotropy > or =0.3, angle< or =70degrees. RESULTS: The patterns and distribution of abnormal DTI-based corticospinal tractographic findings were interruption(10 cases, 76.9%), reduction of fiber volume (8 cases, 61.5%), agenesis of corticospinal tract (3 cases, 23.1%), transcallosal fiber (2 cases, 15.4%) and, aberrant corticospinal tracts (4 cases, 30.8%). Abnormal DTI-based corticospinal tractographic findings were in accordance with the clinical findings of cerebral palsy in 84.6% of the enrolled patients. CONCLUSION: Our results suggest that DTI-FT would be a useful modality in the assessment of the corticospinal tract abnormalities in children with hemiplegic cerebral palsy.
Subject(s)
Child , Humans , Anisotropy , Cerebral Palsy , Diffusion , Magnetic Resonance Spectroscopy , Orientation , Pyramidal TractsABSTRACT
Diffuse axonal injury (DAI) is identified as one of the most important causes of cognitive disorders in patients with traumatic brain injury. Radiologic recognition of DAI can help in understanding the clinical syndrome and in making treatment decisions. However, CT and conventional MRI are often normal or demonstrate lesions that are poorly related to the cognitive disorders present. Recently, diffusion tensor imaging (DTI) and fiber tractography (FT) have been shown to be useful in detecting various types of white matter damage. The aim of this study was to evaluate the feasibility of using DTI and FT to detect lesions in DAI patients, and to correlate these DAI lesions with the patients' cognitive disorders. We investigated 9 normal volunteers and 9 patients with DAI. The DAI patients had impaired intelligence, as well as attention, memory and executive function disorders that restricted their activities of daily living. In the DAI patients, DTI showed abnormal brain areas in the corpus callosum, fornix, frontal and parietal lobe white matter, and FT revealed interruptions of the white matter fibers in the corpus callosum and the fornix when compared with the normal volunteers, while no lesions were found on conventional MRI. DTI and FT can directly visualize DAI lesions, which cannot be reliably detected by conventional methods. Accordingly, both DTI and FT may be useful techniques for the evaluation of DAI, and may have the potential to be applied to planning rehabilitation therapy, and predicting the neurologic prognosis in DAI patients with cognitive disorders.
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PURPOSE: The purpose of this study was to implement a software to visualize tumor and its surrounding fiber tracts simultaneously using diffusion tensor imaging and examine the feasibility of our software for investigating the influence of tumor on its surrounding fiber connectivity. MATERIALS AND METHODS: MR examination including T1-weigted and diffusion tensor images of a patient with brain tumor was performed on a 3.0 T MRI unit. We used the skull-striped brain and segmented tumor images for volume/surface rendering and anatomical information from contrast-enhanced T1-weighted images. Diffusion tensor images for the white matter fiber-tractography were acquired using a SE-EPI with a diffusion scheme of 25 directions. Fiber-tractography was performed using the streamline and tensorline methods. To correct a spatial mismatch between T1- weighted and diffusion tensor images, they were coregistered using a SPM. Our software was implemented under window-based PC system. RESULTS: We successfully implemented the integrated visualization of the fiber tracts with tube-like surfaces, cortical surface and the tumor with volume/surface renderings in a patient with brain tumor. CONCLUSION: Our result showed the feasibility of the integrated visualization of brain tumor and its surrounding fiber tracts. In addition, our implementation for integrated visualization can be utilized to navigate the brain for the quantitative analysis of fractional anisotropy to assess changes in the white matter tract integrity of edematic and peri-edematic regions in a number of tumor patients.
Subject(s)
Humans , Anisotropy , Brain Neoplasms , Brain , Diffusion , Diffusion Tensor Imaging , Magnetic Resonance ImagingABSTRACT
Magnetic resonance diffusion imaging contrasts by water molecule diffusion,reflecting water diffusion status.Owing to the unique mechanism,diffusion imaging is sensitive to anatomic alteration of fiber tract and becomes an important technique in the detection of diffuse axonal injury.Diffusion-weighted imaging shows DAI lesion via emphasizing diffusion composition,diffusion tensor imaging is more sensitive to diffusion anisotropy of the lesion,and fiber tractography can directly demonstrate fiber disruption.MR-diffusion imaging not only improves conspicuity of DAI,but also has grading and prognostic value.