Diffusion Tensor Tractography Study Research Articles

Decoding the superior parietal lobule connections of the superior longitudinal fasciculus/arcuate fasciculus in the human brain

The temporo-parietal (TP) white matter connections between the inferior parietal lobule and superior temporal gyrus as part of the superior longitudinal fasciculus/arcuate fasciculus (SLF/AF) or middle longitudinal fasciculus (MdLF) have been studied in prior diffusion tensor tractography (DTT) studies. However, few studies have been focusing on the higher TP connections of the superior parietal lobule with the temporal lobe. These higher TP connections have been shown to have a role in core processes such as attention, memory, emotions, and language. Our most recent study, for the first time, hinted to the possibility of a long white matter connection interconnecting the superior parietal lobule (SPL) with the posterior temporal lobe in human brain which we call the SLF/AF TP-SPL and for a shorter abbreviation, the TP-SPL. We decided to further investigate this white matter connection using fiber assignment by continuous tracking deterministic tractography and high spatial resolution diffusion tensor imaging on 3T. Five healthy right-handed men (age range 24–37years) were studied. We delineated the SPL connections of the SLF/AF TP bilaterally in five normal adult human brains. Using a high resolution DTT technique, we demonstrate for the first time, the trajectory of a long fiber bundle connectivity between the SPL and posterior temporal lobe, called the SLF/AF TP-SPL (or the TP-SPL), bilaterally in five healthy adult human brains. We also demonstrate the trajectory of the vertically oriented posterior TP connections, interconnecting the inferior parietal lobule (IPL) with the posterior temporal lobe (TP-IPL) in relation to the TP-SPL, arcuate fasciculus and other major language pathways. In the current study, for the first time, we categorized the TP connections into the anterior and posterior connectivity groups and subcategorized each one into the SPL or IPL connections.

The neural connectivity of the intralaminar thalamic nuclei in the human brain: A diffusion tensor tractography study

Research on the neural connectivity of the intralaminar thalamic nuclei (ILN) has been limited. Since the introduction of diffusion tensor imaging (DTI), many probabilistic DTI studies have reported on neural connectivity of neural structures in normal subjects. However, no study on the neural connectivity of the ILN has been reported so far. In this study, using probabilistic DTI, we investigated the neural connectivity of the ILN in normal subjects. A total of 40 healthy subjects were recruited for this study. A seed region of interest was placed on the ILN of the thalamus using the FMRIB Software Library. Connectivity was defined as the incidence of connection between the ILN and target brain areas. We found high connectivity between the ILN and arousal-related areas (prefrontal cortex 100%, reticular formation 100%, pedunculopontine nucleus 97.5%, basal forebrain 95%, and hypothalamus 92.5% at threshold 5), attention related area (prefrontal cortex 100% at threshold 5), and sensori-motor function related areas (primary motor cortex 100%, globus pallidus 100%, putamen 98.8%, premotor cortex 96.3%, primary somatosensory cortex 95.0%, caudate nucleus 92.5%, and posterior parietal cortex 90.0% at threshold 5). Findings of this study showed that ILN has high connectivity with brain areas related to arousal, attention, and sensorimotor function. This result indicates a close association of ILN with these functions in the human brain.

Injury of the cingulum in patients with putaminal hemorrhage: a diffusion tensor tractography study.

Objectives: Little is known about the pathophysiological mechanisms of cognitive impairment in patients with putaminal hemorrhage (PH). Using diffusion tensor tractography, we investigated injury of the cingulum in patients with PH.Methods: We recruited 63 patients with PH, who were classified according to three groups, based on integrity of the cingulum to the lower portion of the genu of the corpus callosum: group A; preserved integrity, group B; discontinuation of integrity in the affected hemisphere, and group C; discontinuation of integrity in both hemispheres.Results: Thirty four patients (54.0%) belonged to group A, 16 patients (25.4%) to group B, and the remaining 13 patients (20.6%) to group C. Regarding the Mini-Mental State Examination, significant differences were observed between group A and group C, and between group B and group C without significant difference between group A and group B (p < 0.05). In terms of the volume of hematoma, significant differences were observed among the three groups (p < 0.05). Regarding the most anterior point of the hematoma, significant differences were observed between group A and groups B and C (p < 0.05); in contrast, regarding the most point of hematoma, significant differences were observed between group C and groups A and B, respectively (p < 0.05).Conclusion: We found that the anterior cingulum is vulnerable to PH. Therefore, our results suggest the necessity for evaluation of the cingulum in patients with PH particularly if the hematoma is large or close to the anterior margin or midline of the brain.

Injury of the Papez circuit in a patient with herpes encephalitis: A diffusion tensor tractography study

Injury of the Papez circuit in a patient with herpes encephalitis: A diffusion tensor tractography study

Recovery of the corticospinal tracts injured by subfalcine herniation: a diffusion tensor tractography study.

Recovery of the corticospinal tracts injured by subfalcine herniation: a diffusion tensor tractography study.

Localized abnormalities in the cingulum bundle in patients with schizophrenia: a Diffusion Tensor tractography study.

The cingulum bundle (CB) connects gray matter structures of the limbic system and as such has been implicated in the etiology of schizophrenia. There is growing evidence to suggest that the CB is actually comprised of a conglomeration of discrete sub-connections. The present study aimed to use Diffusion Tensor tractography to subdivide the CB into its constituent sub-connections, and to investigate the structural integrity of these sub-connections in patients with schizophrenia and matched healthy controls. Diffusion Tensor Imaging scans were acquired from 24 patients diagnosed with chronic schizophrenia and 26 matched healthy controls. Deterministic tractography was used in conjunction with FreeSurfer-based regions-of-interest to subdivide the CB into 5 sub-connections (I1 to I5). The patients with schizophrenia exhibited subnormal levels of FA in two cingulum sub-connections, specifically the fibers connecting the rostral and caudal anterior cingulate gyrus (I1) and the fibers connecting the isthmus of the cingulate with the parahippocampal cortex (I4). Furthermore, while FA in the I1 sub-connection was correlated with the severity of patients' positive symptoms (specifically hallucinations and delusions), FA in the I4 sub-connection was correlated with the severity of patients' negative symptoms (specifically affective flattening and anhedonia/asociality). These results support the notion that the CB is a conglomeration of structurally interconnected yet functionally distinct sub-connections, of which only a subset are abnormal in patients with schizophrenia. Furthermore, while acknowledging the fact that the present study only investigated the CB, these results suggest that the positive and negative symptoms of schizophrenia may have distinct neurobiological underpinnings.

Injury of the spinothalamic tract in a patient with mild traumatic brain injury: Diffusion tensor tractography study

To report on a patient found to have injury of the spinothalamic tract on diffusion tensor tractography following traumatic brain injury. A 29-year-old male patient with head trauma resulting from a pedestrian car accident presented with pain in multiple areas (both subscapular areas, posterior head and neck, both upper trapezius areas, and the right arm and leg). His pain had not improved with various types of conservative management. Evaluations (conventional brain magnetic resonance imaging, electromyography, and whole spine magnetic resonance imaging), performed 2 years after the head trauma, did not reveal any specific abnormality. Fibromyalgia and myofascial pain syndrome were ruled out by physical examination. Injuries of the spinothalamic tracts in both hemispheres were observed on diffusion tensor imaging in terms of the configuration (thinning) and diffusion tensor tractography parameters (decreased fractional anisotropy or tract volume). Some of the pain in the trunk and extremities in this patient could be ascribed to central pain caused by injury of both spinothalamic tracts. We conclude that diffusion tensor tractography provides a useful means of detecting injury of the spinothalamic tract in patients with traumatic brain injury.

Relation between cingulum injury and cognition in chronic patients with traumatic brain injury; diffusion tensor tractography study

Many diffusion tensor imaging (DTI) studies have reported an association between cingulum injury and cognition in patients with traumatic brain injury (TBI) using DTI parameters. In this study, we attempted to investigate the relation between cingulum injury and cognition in chronic patients with TBI, using the integrity of the cingulum as well as DTI parameters. Thirty five consecutive chronic patients with TBI were recruited. The intelligence quotient (IQ) of the Wechsler Intelligence Scale and Memory Assessment Scale (MAS) was used for assessment of cognition. The patients were classified into three groups, according to continuity to the lower portion of the genu of the corpus callosum: type A-both sides of the cingulum showed intact continuity, type B-either cingulum showed a discontinuation, and, type C-both cingulums showed discontinuation. We measured the fractional anisotropy (FA), apparent diffusion coefficient (ADC), and voxel number of both cingulums. The IQ and MAS scores of type A and B were significantly higher than those of type C, respectively (p < 0.05), however, we did not observe a significant difference between type A and type B (p > 0.05). A positive correlation was observed between the FA value of the cingulum, and IQ and MAS, respectively (IQ r = 0.373, p < 0.05, MAS r = 0.357, p < 0.05), and between the voxel number and MAS (r = 0.500, p < 0.05). By contrast, we observed a negative correlation between the ADC value and IQ (r = -0.353, p < 0.05). In terms of integrity to the basal forebrain and DTI parameters of the injured cingulum, DTI findings showed a close association with whole cognition and memory in chronic patients with TBI.

White matter microstructural abnormalities in families multiply affected with bipolar I disorder: a diffusion tensor tractography study

White matter (WM) abnormalities are proposed as potential endophenotypic markers of bipolar disorder (BD). In a diffusion tensor imaging (DTI) voxel-based analysis (VBA) study of families multiply affected with BD, we previously reported that widespread abnormalities of fractional anisotropy (FA) are associated with both BD and genetic liability for illness. In the present study, we further investigated the endophenotypic potential of WM abnormalities by applying DTI tractography to specifically investigate tracts implicated in the pathophysiology of BD. Diffusion magnetic resonance imaging (MRI) data were acquired from 19 patients with BD type I from multiply affected families, 21 of their unaffected first-degree relatives and 18 healthy volunteers. DTI tractography was used to identify the cingulum, uncinate fasciculus (UF), arcuate portion of the superior longitudinal fasciculus (SLF), inferior longitudinal fasciculus (ILF), corpus callosum, and the anterior limb of the internal capsule (ALIC). Regression analyses were conducted to investigate the effect of participant group and genetic liability on FA and radial diffusivity (RD) in each tract. We detected a significant effect of group on both FA and RD in the cingulum, SLF, callosal splenium and ILF driven by reduced FA and increased RD in patients compared to controls and relatives. Increasing genetic liability was associated with decreased FA and increased RD in the UF, and decreased FA in the SLF, among patients. WM microstructural abnormalities in limbic, temporal and callosal pathways represent microstructural abnormalities associated with BD whereas alterations in the SLF and UF may represent potential markers of endophenotypic risk.

CST recovery in pediatric hemiplegic patients: Diffusion tensor tractography study

Many diffusion tensor imaging (DTI) studies have reported an association between corticospinal tract (CST) injury and motor dysfunction. In this study, we investigated CST recovery in 29 pediatric patients with clinical hemiplegia using DTI. We measured the fractional anisotropy (FA), apparent diffusion coefficient (ADC), and asymmetric anisotropy (AA) of both CSTs. The patients were classified into three groups according to severity of CST disruption of the more affected hemisphere. DTI was followed up for 9.34±2.07 months after initial evaluation. The FA value of the more affected CST showed a significant decrease compared to the opposite side at initial and follow up evaluation, respectively (p<0.05). The FA value of both CSTs showed a significant increase at follow up compared to the initial evaluation, while more changes were observed on the more affected side, compared with the less affected side (p<0.05). AA showed a significant decrease at follow up, and showed significant correlation with interval change of FA value of the more affected side, not with that of the less affected side (r=0.543, p<0.05). 19 patients showed change of CST integrity. In the current study, the results of DTI showed recovery of the CST and provided radiologic evidence for a scientific basis of brain plasticity in pediatric patients.

Recovery of injured cingulum in a patient with brain injury: Diffusion tensor tractography study

Little is known about neural recovery of an injured cingulum following brain injury. We report on a patient with brain injury who showed apparent neural recovery of an injured cingulum on follow up diffusion tensor tractography (DTT). A 53-year-old female patient had suffered hypoxic ischemic brain injury for a period of approximately nine hours following spontaneous subarachnoid hemorrhage and intraventricular hemorrhage, and underwent coiling of a left ruptured aneurysm of the posterior communicating artery. She showed severe cognitive impairment, so that she could not be evaluated on the Mini-Mental State Examination, however, her cognition showed improvement to 21 at five months after onset and 24 at 14 months after onset on the Mini-Mental State Examination. On seven-day DTT for the fornix in the patient, we observed a discontinuation in the left crus and thinning of the right crus. However, on 14-month DTT, the thinned right fornical crus had disappeared. Regarding the cingulum, on seven-day DTTs, discontinuations of both cingulums anterior to the genu of the corpus callosum were observed. However, on 14-month follow up DTT, the right cingulum was elongated to the right basal forebrain and no change in the discontinuation of the left cingulum was observed. These changes observed on DTT in both cingulums appeared to indicate recovery of the injured cingulum in this patient. The results of this study may suggest a mechanism for recovery of injured cingulum following brain injury.

Degenerative changes of the corticospinal tract in pediatric patients showing deteriorated motor function: A diffusion tensor tractography study

Objective: We attempted to demonstrate the corresponding degenerative changes of the affected corticospinal tract (CST) in pediatric patients with deteriorated motor function using diffusion tensor tractography (DTT).Methods: We recruited three pediatric patients (corrected age: 2, 6 and 47 months, respectively) who showed impaired motor function.Results: DTT in each patient showed interruption of the CSTs of the hemisphere contralateral to the side of motor impairment. Despite motor impairment and abnormal DTT findings, none of the three patients received rehabilitative therapy. The patients (corrected age: 9, 53 and 59 months, respectively) and their parents visited our clinic again due to deterioration of motor functions. Follow-up DTT of all evaluated patients showed significant degenerative changes in the affected CSTs in accordance with the aggravation of motor impairment.Conclusion: We presented degenerative changes of the affected CSTs in pediatric patients according to the deterioration of motor function.

Anatomical location of the medial lemniscus and spinothalamic tract at the pons in the human brain: A diffusion tensor tractography study

Using diffusion tensor tractography, we investigated the anatomical location of medial lemniscus (ML) and spinothalamic tract (STT) at pons. We recruited 47 healthy volunteers. Evaluation of the anatomical location of ML and STT was performed using the highest probabilistic location at the upper, middle, and lower pons. According to findings, MLs were located around the middle to medial one-third, between midline and lateral boundary of pons in the pontine tegmentum and STTs were located posterolaterally to ML.

White matter damage is associated with memory decline in chronic alcoholics: A quantitative diffusion tensor tractography study

Neuroimaging studies have reported an association between white matter integrity and cognitive performance in normal aging and various neuropathological conditions. We compared alcoholics with controls and hypothesized that the degree of disconnection of white matter fibers would be negatively correlated with memory dysfunction scores. Diffusion tensor imaging (DTI) based tractography and PGI-memory scale (PGIMS) test was performed in 10 abstinent chronic alcoholic and 10 demographically equivalent control men. DTI measures [fractional anisotropy (FA), and mean diffusivity (MD)] from all of the major cerebral tracts were calculated and a comparison was done between patient group and controls. Spearman’s rank correlation coefficient was computed between memory dysfunction score and DTI measures. Compared to controls alcoholic participants had significantly reduced FA in corpus callosum (CC), fornix (FX), and right hemispheric arcuate fasciculus (AF), anterior thalamic radiation (ATR) and inferior longitudinal fasciculus (ILF). A significant inverse correlation with memory dysfunction score was observed with right cingulum, right uncinate fasciculus, right ILF and left ILF. The inverse correlation of memory dysfunction score with FA of white matter tracts suggest that white matter deficit in these white matter fibers may contribute to underlying dysfunction in memory in alcoholism.

Injury of the oculomotor nerve in a patient with traumatic brain injury: diffusion tensor tractography study

A 24-year-old female who had suffered a pedestrian traffic accident underwent conservative management for traumatic diffuse axonal injury at the Department of Neurosurgery in a University Hospital. The patient showed...

Injury of the corticoreticular pathway in patients with proximal weakness following cerebral infarct: Diffusion tensor tractography study

The corticoreticular pathway (CRP) innervates mainly the proximal muscles of extremities. Identification of the CRP by diffusion tensor tractography (DTT) in the human brain has recently become possible. However, little is known about the relation between proximal weakness and injury of the CRP in stroke patients. In this study, we attempted to investigate the usefulness of DTT for elucidation of the relation between proximal motor weakness and injury of the CRP in patients with cerebral infarct. Among 247 consecutive patients with cerebral infarct, four hemiparetic patients who showed more severe weakness in proximal joints (shoulder and hip) than distal joints (finger and ankle) of the affected extremities were recruited for this study. Evaluation of motor function, DTT, and transcranial magnetic stimulation (TMS) for evaluation of the corticospinal tract state by analysis of the characteristics of the motor-evoked potential were performed at the early stage of cerebral infarct (mean: 17.0 days; range: 11–29). The integrity of the CST on DTT findings in the affected hemisphere was preserved in all four patients and TMS findings in terms of latency and amplitude showed within normal range (one patient) and partial injuries (three patients) of the corticospinal tract. By contrast, on DTT of the CRP in the affected hemispheres, we observed Wallerian degeneration in two patients and discontinuations at infarct level in two patients. The injury of the CRP appeared to attribute the proximal weakness of the shoulder and hip observed in these four patients. Therefore, DTT of the CRP would be useful for elucidating the relation between proximal weakness and injury of the CRP in patients with cerebral infarct.

Thalamocortical tract between anterior thalamic nuclei and cingulate gyrus in the human brain: diffusion tensor tractography study

Most portions of the Papez circuit have been identified by diffusion tensor tractography (DTT). However, no DTT study on the proportion of the Papez circuit between the anterior thalamic nuclei and cingulate gyrus has been reported. We attempted to reconstruct the thalamocortical tract between the anterior thalamic nuclei and cingulate gyrus using DTT. All the reconstructed thalamocortical tracts originated from the anterior thalamic nuclei, ascended through the genu of the internal capsule, the anterior limb of the internal capsule, and the white matter around the anterior horn of the lateral ventricle in the anterior and lateral direction, and then terminated at the anterior cingulate gyrus. In terms of FA, MD, and tract volume, no significant differences were observed between hemispheres (p > 0.05). We reconstructed the thalamocortical tract between the anterior thalamic nucleus and cingulate gyrus in the human brain using DTT. We believe that the methodology and results of this study will be helpful to researchers investigating the Papez circuit.

Anatomical location of transcallosal sensorimotor fibers in the human brain: Diffusion tensor tractography study

AbstractMany diffusion tensor tractography (DTT) studies have reported on the topography of transcallosal fibers (TCF). However, little detailed anatomical information on TCF that can be easily applied for clinical purposes is known. Using probabilistic DTT, we attempted to determine the anatomical location of the TCF for motor and sensory function in the human brain. A total of 51 healthy subjects were recruited for this study. Diffusion tensor images (DTIs) were obtained at 1.5 T, and four TCF for the premotor cortex (PMC), the primary motor cortex (M1) for hand and leg, and the primary somatosensory cortex (S1) were obtained using FMRIB software. Locations of the TCF were defined as the highest probabilistic location on the midsagittal slice of the corpus callosum. We measured distances between the most anterior and posterior points of the corpus callosum. The relative mean distances of the highest probabilistic location for the precentral knob PMC (Brodmann area 6 anterior to the precentral knob), hand M1, leg M1, and precentral knob S1 (postcentral gyrus posterior to the precentral knob) TCF were 48.99%, 59.78%, 67.93%, and 73,48% from the most anterior point of the CC, respectively. According to our findings, the precentral knob PMC, hand M1, leg M1, and precentral knob S1 TCF were located at the anterior body, posterior body, posterior body, and isthmus according to Witelson’s classification, respectively.

Motor recovery via aberrant pyramidal tract in a patient with traumatic brain injury: A diffusion tensor tractography study

Motor recovery via aberrant pyramidal tract in a patient with traumatic brain injury: A diffusion tensor tractography study

Precommissural Fornix in the Human Brain: A Diffusion Tensor Tractography Study

PurposeOther than a single case report, no diffusion tensor tractography (DTT) studies of the precommissural fornix in the human brain have been conducted. In the current study, we attempted to visualize the precommissural fornix in the human brain using DTT.Materials and MethodsWe recruited 36 healthy volunteers for this study. Diffusion tensor images were scanned using a 1.5-T scanner, and the precommissural fornix was analyzed using Functional Magnetic Resonance Imaging of the Brain (FMRIB) software. Values of fractional anisotropy (FA), mean diffusivity (MD), and tract volume of the precommissural fornix were measured.ResultsThe precommissural fornix originated from the hippocampal formation on each hemisphere as a crus; both crura were then joined to the body of the fornix. The body of the fornix continued anteriorly to the level just superior to the anterior commissure, where it divided into each column of the precommissural fornix. Each column descended anteriorly to the anterior commissure and terminated in the septal nuclei. Values of FA, MD, and tract volumes of the precommissural fornix did not differ between the right and left hemispheres (p>0.05).ConclusionWe believe that the methodology and results of this study would be helpful to future research on the precommissural fornix and in the elucidation of the pathology of diseases involving the precommissural fornix.