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To correlate the resting metabolism of hand knob and hand function after stroke, diffuse tensor tractography (DTT) and 18F-fluorodeoxyglucose position emission tomography (18F-FDG PET) were used to evaluate constructible state of white matter tract and metabolic state of gray matter, respectively.
A total of 17 patients were included in the study, who had suffered a stroke with hand weakness, after a stroke. They underwent diffusion tensor analysis and FDG PET in the subacute period. The ratio of both hemisphere parameters in voxel number of fibers, fractional anisotropy (FA) and apparent diffusion coefficient obtained by corticospinal tract as constructed by DTT, and the metabolism of hand knob area on cerebral cortex obtained from 18F-FDG PET were calculated. Hand movement scale was evaluated on the day of FDG PET or tractography, and at 6 months after onset.
Difference of FA in DTT between both hemispheres and hand knob metabolism in FDG PET significantly correlated with the hand movement scale at the subacute stage and 6 months after onset. However, the difference of both hemispheres in DTT and metabolism of hand knob area was not significant.
Resting metabolism on hand knob in FDG PET correlated with hand function after stroke.
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To compare diffusion tensor tractography (DTT) and motor evoked potentials (MEPs) for estimation of clinical status in patients in the subacute stage of stroke.
Patients with hemiplegia due to stroke who were evaluated using both DTT and MEPs between May 2012 and April 2015 were recruited. Clinical assessments investigated upper extremity motor and functional status. Motor status was evaluated using Medical Research Council grading and the Fugl-Meyer Assessment of upper limb and hand (FMA-U and FMA-H). Functional status was measured using the Modified Barthel Index (MBI). Patients were classified into subgroups according to DTT findings, MEP presence, fractional anisotropy (FA) value, FA ratio (rFA), and central motor conduction time (CMCT). Correlations of clinical assessments with DTT parameters and MEPs were estimated.
Fifty-five patients with hemiplegia were recruited. In motor assessments (FMA-U), MEPs had the highest sensitivity and negative predictive value (NPV) as well as the second highest specificity and positive predictive value (PPV). CMCT showed the highest specificity and PPV. Regarding functional status (MBI), FA showed the highest sensitivity and NPV, whereas CMCT had the highest specificity and PPV. Correlation analysis showed that the resting motor threshold (RMT) ratio was strongly associated with motor status of the upper limb, and MEP parameters were not associated with MBI.
DTT and MEPs could be suitable complementary modalities for analyzing the motor and functional status of patients in the subacute stage of stroke. The RMT ratio was strongly correlated with motor status.
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To investigate whether early stage diffusion tensor tractography (DTT) values predict motor function at 3 months after onset in supratentorial stroke patients with severe motor involvement.
A retrospective study design was used to analyze medical records and neuroimaging data of 49 supratentorial stroke patients with severe motor involvement. Diffusion tensor imaging was assessed within 3 weeks after stroke in all patients. Three-dimensional tractography of the ipsilateral corticospinal tract (CST) was performed using the fiber assignment of the continuous tracking algorithm. The two-step DTT analysis was used. The first step was classification according to ipsilateral CST visualization. The second step was a quantitative analysis of the visible-CST group parameters. Motor function was assessed at 2 weeks and at 3 months after stroke. Comparative and correlation analyses were performed between DTT-derived measures and motor assessment scores.
Motor function of the upper extremity at 3 months after stroke was significantly higher in the visible-CST group than that in the nonvisible-CST group (p<0.05). Early stage fractional anisotropy was of DTT correlated significantly with upper extremity motor function at 3 months after stroke in the visible-CST group (p<0.05).
These results demonstrate that early DTT-derived measures predict motor recovery in the upper extremity at 3 months after onset in supratentorial stroke patients with severe motor involvement.
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Kernohan-Woltman notch phenomenon (KWP) is an ipsilateral motor weakness due to compression of the contralateral cerebral peduncle. We report two cases of KWP following traumatic brain injury. In case 1, ipsilateral hemiplegia was noted after right subdural hemorrhage. Although magnetic resonance imaging showed no abnormal signal changes on cerebral peduncle, diffusion tensor tractography (DTT) revealed interruption of corticospinal tract (CST) at lower level of the midbrain level. In case 2, there was abnormal signal change of the right cerebral peduncle contralateral to the primary lesion and we could not reconstruct right CST. Case 1 showed unsatisfactory motor recovery even after 15 months, and follow-up DTT showed no change. In case 2, follow-up DTT was not performed, but her ipsilateral hemiparesis had almost disappeared during the 15 months. DTT would be useful in detecting ipsilateral hemiparesis due to KWP and the clinical course may differ according to the lesion characteristics.
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Rotavirus encephalopathy (RE) is a benign afebrile seizure associated with acute gastroenteritis caused by rotavirus infection. We investigated the diffusion tensor tractography (DTT) findings of a patient with RE. The patient was a 30-month-old female that had experienced a brief, generalized convulsive seizure. On the day of admission, the patient had vomiting and experienced watery diarrhea. Her stool was positive for rotavirus antigen. At onset, the patient displayed a drowsy and delirious mental status; later, a splenial lesion of the corpus callosum was found on MRI. One week later, the patient's condition improved and the splenial lesion had disappeared by conventional MRI. Initial DTI showed decreased fractional anisotropy (FA) values of fornix, as well as of the corpus callosum. A follow-up DTT showed a restored interrupted right fonical crus and increased FA values of corpus callosum and fornix. These results highlight the implications of the probability of not only a corpus callosum injury, but a fornix injury as well, in this patient with RE.
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