Diffusion tensor brain imaging and tractography

Diffusion-tensor MR imaging is a promising tool to evaluate white-matter integrity by quantitative and graphic maps including neural fiber tractogram. Current challenges afoot are to obtain higher quality diffusion-weighted MR images (high SNR, isotropic voxel, and high spatial resolution), to create a robust mathematical framework to process the data, to construct a user-friendly computer-based algorithm, to reveal determinants of diffusion process, and to establish analytical methodology.     

Magnetic resonance imaging in central pontine myelinolysis.

Magnetic resonance imaging (MRI) was performed in two patients in whom a clinical diagnosis of central pontine myelinolysis (CPM) had been made. MRI showed lesions in the pons in both cases about 2 years after the illness, at a time when the spastic quadriparesis and pseudobulbar palsy had recovered. The persisting abnormal signals in CPM are likely to be due to fibrillary gliosis. Persistence of lesions on MRI means that the diagnosis of CPM may be electively, after the acute illness has resolved.     

Diffusion tensor imaging and tractography of human brain development

Over the past decade, diffusion tensor imaging (DTI) has offered researchers and clinicians a new noninvasive window into the developing human brain, from preterm infants through adolescents and young adults. DTI improves on conventional MR imaging, such as T1-weighted and T2-weighted sequences, through its sensitivity to many microstructural features of neural organization. This has enabled visualization of the early cerebral laminar architecture in premature infants, of developing white matter before myelination, and of the microarchitecture of the cerebral cortex during preterm maturation. DTI provides reproducible quantitative measures, such as mean diffusivity and fractional anisotropy, that reflect the underlying tissue properties of gray matter and white matter and may therefore become useful as developmental milestones for the improved assessment of abnormal brain maturation. Furthermore, three-dimensional fiber tractography based on DTI can reveal the developing axonal connectivity of the human brain as well as aberrant connectivity in structural brain malformations. In this article, applications of DTI and fiber tractography to the study of human brain development are reviewed. The new insights into brain maturation afforded by DTI promise to improve the diagnostic evaluation of an array of congenital, metabolic, and neurodevelopmental disorders.     

Diffusion tensor imaging and fiber tractography in acute stroke

Diffusion tensor imaging (DTI) permits the quantitative evaluation of white matter pathology using measures of diffusion anisotropy. Fiber tractography based on DTI can reveal the three-dimensional white matter connectivity of the human brain. DTI fiber tractography is used to localize stroke lesions in relation to functionally important pathways and to assess wallerian degeneration, which may allow more accurate prognosis of long-term recovery or disability. DTI also improves the evaluation of hypoxic-ischemic injury to the developing brain of newborns and infants. DTI and fiber tractography may prove useful in elucidating alterations in brain connectivity resulting from neuroplasticity after stroke.     

Diffusion tensor magnetic resonance imaging tractography in cognitive disorders

PURPOSE OF REVIEW: The advent of novel techniques for tracing connections in vivo, such as diffusion tensor magnetic resonance imaging tractography, allows us, for the first time in the human brain, to study the microstructural integrity of white matter fibres and perform virtual dissections of large scale neurocognitive networks. This review will outline the advantages and limitations of applying diffusion tensor magnetic resonance imaging to the study of cognitive and behavioural disorders in neurology and psychiatry. RECENT FINDINGS: Diffusion tensor magnetic resonance imaging has been used to re-explore the anatomy of white matter tracts in the living human brain and to create connectional models of brain function. Beyond its application to classical disconnection syndromes, diffusion tensor magnetic resonance imaging is becoming an important tool to extend the disconnectionist paradigm to neurodevelopmental and neurodegenerative disorders. SUMMARY: For the first time, we are able to correlate disconnecting lesions with clinical symptoms in vivo and test the disconnection mechanism directly in cognitive disorders. With diffusion tensor magnetic resonance imaging tractography alone and in combination with other magnetic resonance imaging techniques, researchers are able to detect abnormalities in white matter that are not visible with conventional magnetic resonance imaging.     

Recovery after central pontine myelinolysis

Summary Central pontine myelinolysis (CPM) is known to be almost universally fatal. Most published cases are based on autopsy reports, whereas antemortem diagnosis is rare. We present a case in which the diagnosis of CPM was confirmed by computed tomography (CT); the patient had two symptoms not previously reported and made a remarkable recovery.

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Zusammenfassung Es ist bekannt, daß die zentrale pontine Myelinolyse praktisch immer tödlich endet. Die meisten veröffentlichten Fälle sind auf Grund der Autopsie diagnostiziert worden, während eine prämortale Diagnose selten ist. Der vorliegende Fall einer zentralen pontinen Myelinolyse wurde durch Computertomographie intra vitam bestätigt. Der Patient wies zwei früher nicht beschriebene Symptome auf und erholte sich in bemerkenswerter Weise.

     

Behavioral manifestations of central pontine myelinolysis

A young woman with a clinical history and magnetic resonance imaging scan consistent with central pontine myelinolysis came to medical attention because of prominent behavioral symptoms. Marked clinical recovery occurred despite persistent radiologic abnormalities. Rapid correction of hyponatremia was probably related to the development of the central pontine myelinolysis. A normal computed tomographic scan and the absence of brain-stem signs delayed accurate diagnosis.     

Brachial diplegia in central pontine myelinolysis

Summary A patient developed weakness in the upper limbs, eventually causing brachial diplegia with only slight paresis of the legs after rapid correction of severe hyponatraemia. Pseudobulbar palsy, mental confusion and urinary incontinence were also present. CT scan showed a zone of lucency in the pons. Clinical recovery occurred and the zone of lucency had disappeared 12 months after the appearance of the neurological signs.     

Idiopathic central pontine myelinolysis in childhood

Central pontine myelinolysis (CPM) is rare in childhood with only a few cases reported in world literature. We report a 7-year-old male who presented with acute ataxia, swallowing difficulties, dysarthria, and radiological features consistent with the disorder. He improved remarkably with oral prednisolone therapy and was almost back to normal by 2 weeks. A review of the literature is also included.     

Computerized tomography in central pontine myelinolysis

We describe an autopsy-proven case of central pontine myelinolysis (CPM) with premortem computerized tomographic (CT) visualization of the lesion on two scans, performed with an interval of 2 weeks. This case demonstrates the capability of CT to support the clinical diagnosis of central pontine myelinolysis. Identification of the condition should facilitate prompt initiation of aggressive supportive care.     

Association of central pontine myelinolysis and Marchiafave-Bignami disease

Combined pathologic features of central pontine myelinolysis and Marchiafava-Bignami disease occurred in a 53-year-old man with chronic alcoholism. This association is rare despite the basic similarities of these two disorders. The combination of both conditions in the same patient suggests a common pathogenetic mechanism.     

脑桥中央及脑桥外髓鞘溶解症1例

脑桥中央及脑桥外髓鞘溶解症是常见的渗透性脱髓鞘疾病,近年来报道的病例逐渐增多,随着重症监护的发展、核磁共振的早期诊断,患者预后得到较大改善。现将解放军总医院神经内科重症监护室收治的1例脑桥中央及脑桥外髓鞘溶解症及诊治经验报道如下。     

Subclinical central pontine myelinolysis following liver transplantation

Central pontine myelinolysis (CPM) is a demyelinating disorder of unknown origin that almost exclusively affects the central portion of the basis pontis, and is one of the fatal neurological complications after liver transplantation. We describe two children with CPM detected incidentally after liver transplantation. To our knowledge, this is the first report of CPM diagnosed antemortem in children who had undergone liver transplantation. In our patients, there were no clinical manifestations associated with CPM. We conclude that, including silent cases such as our patients, CPM may be more prevalent than previously appreciated following liver transplantation.     

Peduncular hallucinosis secondary to central pontine myelinolysis

Peduncular hallucinations are generally associated with lesions in the midbrain. They have rarely been associated with central pontine myelinolysis, a condition associated with rapid alterations in serum sodium and chronic alcoholism. Described herein is the case of a 46‐year‐old man who developed typical peduncular hallucinations, whose imaging demonstrated central pontine myelinolysis. After alcohol cessation and neuroimaging resolution, the patient's hallucinatory phenomena abated.     

Dystonia in central pontine myelinolysis without evidence of extrapontine myelinolysis.

A 44-year-old female is described who developed persistent upper extremity and orolingual dystonia several weeks after suspected onset of central pontine myelinolysis (CPM), later confirmed by characteristic pontine lesions on MRI. No foci of the extrapontine myelinolysis were evident. This case confirms that dystonia may be a late and persistent sequela of CPM and may occur in the absence of visible lesions outside the brainstem.