Prefronto-thalamic tract injury and cognitive outcome according to external ventricular drainage location in stroke patients.

OBJECTIVES: We investigated the characteristics of prefronto-thalamic tract (PF-TT) injuries in stroke patients using diffusion tensor tractography (DTT) and assessing cognitive outcome according to location of the external ventricular drainage (EVD). METHODS: Forty-five consecutive stroke patients who underwent EVD and 24 control subjects were recruited. The patients were classified into three groups: group A (EVD on the lesion or one side, 17 patients), group B (EVD on the hemisphere opposite to the lesion, 12 patients), and group C (EVD on both sides, 16 patients). Mini-Mental State Examination (MMSE) results were performed at the beginning (average 2.27 months from onset) and end (average 4.19 months from onset) of rehabilitation. Three parts of the PF-TT (dorsolateral PF-TT[DLPF-TT], ventrolateral PF-TT[VLPF-TT], orbitofronto-thalamic tract[OF-TT]) were reconstructed and the fractional anisotropy (FA) and tract volume (TV) measurements were obtained. RESULTS: With the EVD on the stroke-affected side, the values of FA and TV of all three parts of the PF-TTs in three patient groups were lower than those of the control group (p < 0.05). With the EVD on the unaffected side, the FA values of the DLPF-TT in groups B and C and the OF-TT in group C were lower than those of the control group (p < 0.05). There was no difference in initial MMSE score among three patient groups; however, group A had a higher mean follow-up MMSE score than that of groups B and C (p < 0.05). CONCLUSIONS: Patients who underwent EVD of the affected hemisphere showed better results in terms of the PF-TT injury and cognitive outcome than patients who underwent EVD through the unaffected hemisphere or through both hemispheres.

White Matter Abnormalities in Traumatic Subarachnoid Hemorrhage: A Tract-Based Spatial Statistics Study.

BACKGROUND The pathophysiology of traumatic subarachnoid hemorrhage and brain injury has not been fully elucidated. In this study, we examined abnormalities of white matter in isolated traumatic subarachnoid hemorrhage patients by applying tract-based spatial statistics. MATERIAL AND METHODS For this study, 10 isolated traumatic subarachnoid hemorrhage patients and 10 age- and sex-matched healthy control subjects were recruited. Fractional anisotropy data voxel-wise statistical analyses were conducted through the tract-based spatial statistics as implemented in the FMRIB Software Library. Depending on the intersection between the fractional anisotropy skeleton and the probabilistic white matter atlases of Johns Hopkins University, we calculated mean fractional anisotropy values within the entire tract skeleton and 48 regions of interest. RESULTS The fractional anisotropy values for 19 of 48 regions of interest showed significant divergences (P<0.05) between the patient group and control group. The regions showing significant differences included the corpus callosum and its adjacent neural structures, the brainstem and its adjacent neural structures, and the subcortical white matter that passes the long neural tract. CONCLUSIONS The results demonstrated abnormalities of white matter in traumatic subarachnoid hemorrhage patients, and the abnormality locations are compatible with areas that are vulnerable to diffuse axonal injury. Based on these results, traumatic subarachnoid hemorrhage patients also exhibit diffuse axonal injuries; thus, traumatic subarachnoid hemorrhage could be an indicator of the presence of severe brain injuries associated with acute or excessive mechanical forces.

Dysphagia prognosis prediction via corticobulbar tract assessment in lateral medullary infarction: a diffusion tensor tractography study.

We investigated the capacity for dysphagia prognosis prediction using diffusion tensor tractography (DTT) to assess the state of the corticobulbar tract (CBT) during the initial period following lateral medullary infarction (LMI). Twenty patients with LMI and 20 control subjects were recruited for this study. The patients were classified into two subgroups: subgroup A (16 patients with nasogastric tube required for six months or less after LMI onset) and subgroup B (4 patients with nasogastric tube required for more than six months after onset). DTT was used to reconstruct the CBTs of each patient and control subject, and the fractional anisotropy (FA) and tract volume (TV) measurements were obtained. In the affected hemisphere, the FA value of the CBT was significantly lower in subgroup B than in subgroup A and the control group (p < 0.05), with no significant difference between subgroup A and the control group. In the affected and unaffected hemispheres, the TV values of CBT in subgroups A and B were lower than those of the control group (p < 0.05), with no significant difference between subgroups A and B. In addition, among the four patients of subgroup B, reconstruction of the CBT was not possible in three patients, and the remaining patients exhibited on old lesion in the corona radiate involving descending pathway of the CBT in the affected hemisphere. We found that the injury severity of the CBT in the affected hemisphere appeared to be related to a poor dysphagia prognosis following LMI. Our results suggest that evaluation of the CBT state during the early post-LMI could be useful for dysphagia prognosis prediction.

Dysphagia in Lateral Medullary Syndrome: A Narrative Review.

Dysphagia is a common clinical feature of lateral medullary syndrome (LMS) and is clinically relevant because it is related to aspiration pneumonia, malnutrition, increased mortality, and prolonged hospital stay. Herein, the pathophysiology, prognosis, and treatment of dysphagia in LMS are reviewed. The pathophysiology, prognosis, and treatment of dysphagia in LMS are closely interconnected. Although the pathophysiology of dysphagia in LMS has not been fully elucidated, previous studies have suggested that the medullary central pattern generators coordinate the pharyngeal phases of swallowing. Investigation of the extensive neural connections of the medulla oblongata is important in understanding the pathophysiologic mechanism of dysphagia in LMS. Previous studies have reported that most patients with dysphagia in LMS have a relatively good prognosis. However, some patients require tube feeding for several months, even years, due to severe dysphagia, and little has been reported about conditions associated with a poor prognosis of dysphagia in LMS. Concerning specific therapeutic modalities for dysphagia in LMS, in addition to general modalities used for dysphagia treatment in stroke patients, non-invasive modalities, including repetitive transcranial magnetic stimulation and transcranial direct current stimulation, as well as invasive modalities, such as botulinum toxin injection, balloon catheter dilatation, and myotomy for relaxation of the cricopharyngeal muscle, have been applied. For the appropriate application of therapeutic modalities, clinicians should be aware of the recovery mechanisms and prognosis of dysphagia in LMS. Further studies on this topic, as well as studies involving large numbers of subjects on specific therapeutic modalities, should be encouraged.

White Matter Abnormalities in Spontaneous Subarachnoid Hemorrhage: A Tract-Based Spatial Statistics Study.

BACKGROUND AND PURPOSE: We investigated white matter abnormalities in patients with spontaneous subarachnoid hemorrhage following aneurysmal rupture, by using tract-based spatial statistics. METHODS: Sixteen patients with spontaneous subarachnoid hemorrhage due to aneurysmal rupture and 18 age- and sex-matched healthy control subjects were recruited. Voxel-wise statistical analysis of fractional anisotropy data was performed by using tract-based spatial statistics as implemented in the Functional Magnetic Resonance Imaging of the Brain Software Library. We calculated mean fractional anisotropy values across the tract skeleton and within 48 regions of interest based on the intersections between the fractional anisotropy skeleton and the probabilistic Johns Hopkins University white matter atlases. RESULTS: Comparing the patient and control groups, the fractional anisotropy values of 44 regions of interest among the 48 regions of interest showed significant differences (P<0.05). However, significant differences were not observed in the remaining 4 regions of interest (both retrolenticular parts of the internal capsule, the right superior longitudinal fasciculus, and the right superior corona radiata; P>0.05). CONCLUSIONS: By undertaking tract-based spatial statistics analysis, we detected wide-ranging white matter abnormalities in patients with spontaneous subarachnoid hemorrhage. Registration: URL: http://www.e-irb.com/index.jsp. Unique identifier: 2019-06-032.

Outcome of Transforaminal Epidural Steroid Injection According to Severity of Cervical Foraminal Stenosis.

BACKGROUND: Cervical transforaminal epidural steroid injection (TFESI) is considered one of the most effective treatments for radicular pain induced by cervical foraminal stenosis. PURPOSE AND DESIGN: We sought to evaluate the treatment outcome of TFESI according to the severity of cervical foraminal stenosis. In our retrospective study there were 53 patients with cervical radiculopathy due to cervical foraminal stenosis. OUTCOME MEASURES: Pain intensity was evaluated using a numeric rating scale (NRS) at pretreatment, 2 weeks, and 1, 2, and 3 months after TFESI. METHODS: Patients were divided into 2 groups according to the severity of stenosis by cervical axial magnetic resonance imaging findings. Twenty-two patients were assigned to group A (nonsevere stenosis), and 31 patients were assigned to group B (severe stenosis). RESULTS: Thirty-seven (69.8%) of 53 patients showed successful treatment outcome (>50% reduction in the NRS score at 3 months). The patients in both groups showed a significant decrease in NRS scores at 2 weeks and at 1, 2, and 3 months after TFESI. However, the effect of TFESI was not significantly different between patients with nonsevere cervical foraminal stenosis and those with severe cervical foraminal stenosis. CONCLUSIONS: The treatment outcome of cervical TFESI did not different according to the severity of cervical foraminal stenosis. However, on the basis of our results, we suggest that TFESI can be a beneficial clinical option for managing radicular pain due to cervical foraminal stenosis.