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Biomedical subjects

T P Naidich

Publications and source records attributed to T P Naidich.

At least 19 recordsLinked to original sources

Acute traumatic central cord syndrome: MRI-pathological correlations.

The acute traumatic central cord syndrome (ATCCS) is commonly stated to result from an injury which affects primarily the center of the spinal cord and is frequently hemorrhagic. To test the validity of this widely disseminated hypothesis, the magnetic resonance images [MRI] of 11 consecutive cases of ATCCS caused by closed injury to the spine were analyzed and correlated with the gross pathological and histological features of 3 cervical spinal cords obtained at post mortem from patients with ATCCS, including 2 of patients studied by MRI. The MRI studies were performed acutely (18 h to 2 days after injury) in 7 patients and subacutely (3-10 days after injury) in 4. Ten of the 11 patients had pre-existing spondylosis and/or canal stenosis. The 11th suffered a cervical fracture. All patients exhibited hyperintense signal within the parenchyma of the cervical spinal cord on gradient echo MRI. None showed MRI features characteristic of hemorrhage on T1-weighted spin echo or T2-weighted gradient echo studies. Gross and histological examination of the necropsy specimens showed no evidence of blood or blood products within the cord parenchyma: the primary finding was diffuse disruption of axons, especially within the lateral columns of the cervical cord in the region occupied by the corticospinal tracts. The central gray matter was intact. In patients with ATCCS, the predominant loss of motor function in the distal muscles of the upper limbs may reflect the importance of the corticospinal tract for hand and finger function in the primate. In this study, the MRI and pathological observations indicate that ATCCS is predominantly a white matter injury and that intramedullary hemorrhage is not a necessary feature of the syndrome; indeed, it is probably an uncommon event in ATCCS. We suggest that the most common mechanism of injury in ATCCS may be direct compression of the cervical spinal cord by buckling of the ligamenta flava into an already narrowed cervical spinal canal; this would explain the predominance of axonal injury in the white matter of the lateral columns.

Adult

MR imaging of tuberous sclerosis: pathogenesis of this phakomatosis, use of gadopentetate dimeglumine, and literature review.

Findings on cranial magnetic resonance (MR) images were correlated with known histopathologic findings in 42 patients with tuberous sclerosis (TS), 17 of whom received gadopentetate dimeglumine, to extend the range of signs on MR images. Four neuroradiologists recorded the number, sites, configurations, and relative signal intensities of intracranial abnormalities. White matter lesions, found in 39 patients (93%), showed four distinct patterns: (a) straight or curvilinear bands extending radially from the ventricle through the cerebral mantle toward the cortex, (b) wedge-shaped lesions, (c) nonspecific conglomerate foci, and (d) cerebellar radial bands. It is concluded that cortical tubers, white matter lesions, subependymal nodules, and sub-ependymal giant cell astrocytomas (SGCAs) may be enhanced after administration of gadopenetetate dimeglumine. Enhancement of a TS lesion does not indicate neoplastic transformation into SGCA. Imaging surveillance every 12 months appears indicated during the peak ages (8-18 years) of occurrence of SGCA. The appearance of white matter lesions supports the theory that the cerebral lesions of TS may be caused by disordered migration of dysgenetic cells.

Adolescent

Spontaneous intracranial hypotension with pachymeningeal enhancement on MRI.

Spontaneous intracranial hypotension (SIH) is a rarely reported syndrome of spontaneously occurring postural cephalalgia associated with low CSF pressure. We report a case of SIH in which MRI of the brain revealed diffuse symmetric pachymeningeal enhancement that resolved without specific therapy.

Central Nervous System Diseases

The CT and MR evaluation of migrational disorders of the brain. Part II. Schizencephaly, heterotopia and polymicrogyria.

The migrational disorders are a rare group of congenital malformations of the brain. They consist of the following entities - lissencephaly (agyria - pachygyria), pachygyria, schizencephaly, heterotopia and polymicrogyria. We studied 40 children with migrational disorders radiologically with CT and MR. This article (Part II) deals with our patients with schizencephaly, heterotopia and polymicrogyria. These patients presented clinically with a variety of symptoms. The most common were seizures, delayed development, failure to thrive and hydrocephalus. CT and MR both demonstrated the characteristic findings in all of our patients except the polymicrogyria group. The gray matter and cleft abnormalities seen in these disorders were demonstrated with CT and MR. However, MR provided better delineation of these disorders than CT. Because some forms of migrational disorders can be inherited, it is extremely important for the radiologist to understand the characteristic findings for correct diagnosis which is essential for parental counseling.

Brain

The CT and MR evaluation of migrational disorders of the brain. Part I. Lissencephaly and pachygyria.

The migrational disorders are a rare group of congenital malformations of the brain. They consist of the following entities--lissencephaly (agyria-pachygyria), pachygyria, schizencephaly, heterotopia and polymicrogyria. We studied 40 children with migrational disorders radiologically with CT and MR. This article (part I) deals with our patients their characteristic CT and MR findings along with their clinical presentation and course. These patients presented with one or a combination of the following symptoms, hypotonia, seizures, failure to thrive, microcephaly and occasionally hydrocephalus. These two groups of migrational disorders have abnormalities affecting the gyral-sulcal pattern of the cortex and gray-white matter distribution of the brain. MR provided better delineation of these disorders than CT. Because some forms of the migrational disorders can be inherited, it is extremely important for the radiologist to understand the characteristic findings for correct diagnosis which is essential for parental counseling.

Brain

Craniofacial dermoids.

Thirty-two patients with nasal dermal sinuses and cysts were treated during the 10-year period from 1978 to 1987. These patients presented with midline cysts (N = 18) or sinus ostia (N = 14). Only 6 of the 32 patients manifested intracranial extension (19 percent). All the patients with intracranial extension exhibited an intracranial mass on preoperative CT scans. Ten patients with no CT evidence of intracranial mass were noted to have only a fibrous cord extending to the base of the foramen cecum. In 4 of these 10 patients, craniotomy confirmed that there was no intracranial extension of the dermoid. Four other patients presented with sinus ostia at the base of the columella. None of these 4 patients had intracranial extension. Clinical examination and preoperative CT scans provide most of the information needed to determine the nature, course, and extent of these lesions.

Adolescent

The natural history of repaired myelomeningocele.

With aggressive management based on careful evaluation, children afflicted with myelomeningocele can achieve their maximum potential. Sonography, MR imaging and CT myelography all play important roles in their evaluation.

Dermoid Cyst

Magnetic resonance imaging and computerized tomography in central hypoventilation.

Central hypoventilation syndrome (CHS) is a disorder of respiratory control. It may be an idiopathic primary disease or it may be the secondary consequence of an infectious process or Chiari II malformation. Clinical data suggest that the primary defect involves the brainstem respiratory centers. To date, pathologic evaluation has linked primary CHS with decreased density of neurons and myelinated nerve fibers in the medulla and brainstem gliosis, and absence of the external arcuate nucleus. Magnetic resonance imaging (MRI) is now considered the most reliable imaging technique for evaluating the brainstem. In the hope of finding gross structural abnormalities that might correlate with the clinical and pathologic features of CHS, we used MRI and computerized tomography (CT) to evaluate the brain, brainstem, and spinal cord of 17 infants and children with central hypoventilation (11 primary, 6 secondary). Each of the 11 children with primary CHS demonstrated a normal brainstem and spinal cord by MRI. However, 9 of 11 infants had mild ventricular dilatation and modest prominence of the sulci interpreted as either mild atrophy or mild extraventricular obstructive hydrocephalus. Results of studies in the one child with postinfectious disease were normal. The 5 infants with Chiari II malformation demonstrated characteristic brainstem changes. MRI results modified clinical care, resulting in symptomatic improvement after hindbrain decompression by cervical laminectomy in 1 infant and surgical drainage of syringobulbia in 1 child. In summary, in primary CHS, the MRI and CT provided evidence for a more diffuse CNS process rather than a specific brainstem lesion. Such a lesion may be too small or too subtle to resolve with MRI or CT. In secondary central hypoventilation, MRI modified surgical management in 2 cases, resulting in symptomatic improvement of hypoventilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Arnold-Chiari Malformation

Scalp and calvarial masses of infants and children.

Review of 70 children presenting with a solitary nontraumatic lump on the head revealed that 61% of the lesions were dermoid tumor, 9% were cephalhematoma deformans, 7% were eosinophilic granuloma, and 4% were occult meningoceles and encephaloceles. Most of the dermoid cysts occurred along sutural lines, but some did not. One of the eosinophilic granulomas was located over the sagittal suture. Seventeen per cent of the "lumps" had significant intracranial extension. An additional 20% of the lumps extended intracranially, but only to the dura mater. Work-up of these lesions should include initial plain skull roentgenograms to assess multiplicity and appropriate computed tomographic scans to assess possible intracranial extension.

Adolescent

The CT and MR evaluation of lissencephaly.

Lissencephaly is a rare congenital malformation of the brain that has characteristic radiographic and clinical findings. Fifteen cases of lissencephaly were studied with CT and/or MR, and a classification was developed based on these cases and the description of this abnormality found in the literature. These findings can be divided into two groups, primary and secondary. The primary findings consist of (1) a cerebral surface that is agyric or agyric with pachygyric areas, (2) a cerebral contour that is oval or "hourglass" due to lack of or incomplete opercularization of the brain, and (3) an abnormal gray-white-matter distribution in the cerebral hemispheres. The primary findings are necessary to make the diagnosis, which can be made with either CT or MR; however, MR provided better delineation than CT of the cerebral surface and contour as well as better gray-white-matter differentiation in the lissencephalic brains. We believe MR is the technique of choice for evaluating patients with lissencephaly because it is safer and more versatile than CT and provides better delineation of the brains of children.

Brain

Common congenital brain anomalies.

Craniocerebral malformations remain enigmas to many radiologists because their pathogeneses are obscure, noninvasive imaging modalities could not display them in detail until recently, and concise classifications have been lacking. In this article the MRI findings of the most common congenital brain malformations are presented with an emphasis on the characteristic features of each malformation and the clinical symptoms and course.

Abnormalities, Multiple

Hippocampal formation and related structures of the limbic lobe: anatomic-MR correlation. Part I. Surface features and coronal sections.

Correlation of magnetic resonance (MR) images with cryomicrotome sections and formalin-fixed sections of human brain documents that spin-echo MR imaging with short repetition time/short echo time pulse sequences can display the surface gyri of the inferomedial temporal lobe, including the temporal pole, the parahippocampal gyrus, the isthmus of the cingulate gyrus, the lateral and medial occipitotemporal gyri, and the inferior temporal gyrus; the associated sulci including the rhinal and collateral sulci, the occipitotemporal sulcus, and the anterior calcarine sulcus; the components and fiber tracts of the hippocampal formation including the pes hippocampi, the hippocampus, the subiculum, the dentate gyrus, the subsplenial gyri, the alveus, the fimbria, and the fornix; the fissures and sulci associated with the hippocampal formation, including the hippocampal fissure, dentatofimbrial fissure, and the choroidal fissure; the continuity between the cingulate gyrus and the parahippocampal gyrus through the isthmus of the cingulate gyrus; and the continuity between the callosal sulcus and the hippocampal fissure.

Hippocampus

Hippocampal formation and related structures of the limbic lobe: anatomic-MR correlation. Part II. Sagittal sections.

Magnetic resonance (MR) images in the sagittal plane display the lengths of the parahippocampal gyrus, subiculum, dentate gyrus, hippocampus, fimbria, fornix, hippocampal fissure, choroidal fissure, and temporal horn, and the anatomic relationships of these structures to the surrounding brain. Correlation of these images with anatomic specimens provides criteria for identifying these structures confidently on routine clinical MR imaging.

Hippocampus

Intraoperative sonography in spinal dysraphism and syringohydromyelia.

The use of intraoperative sonography was analyzed in 24 patients with spinal dysraphism and syringohydromyelia in order to determine the role of real-time sonography in the surgical management of these patients. Specific diagnoses included tethered cord (nine), syringohydromyelia (seven), congenital tumor unassociated with a tethered cord (four), diastematomyelia (three), and occult sacral meningocele (one). Intraoperative sonography determined the exact relationship of congenital tumors to the cord before opening the dura, which allowed a more precise approach to the mass. Intraoperative sonography identified the lower end of the syrinx cavities, which allowed optimal catheter placement. Fibroglial scar tissue, which may compartmentalize these syrinx cavities, was clearly shown, and the efficacy of shunt catheter placement was immediately determined. In diastematomyelia, intraoperative sonography identified the relationship of the hemicords to bony, cartilaginous, and/or fibrous septa and demonstrated the effect on the tethered hemicords of removing these septa and constructing a single dural sac from the two dural sacs that had enclosed the hemicords. Since significant surgical decisions are based on these sonographic observations, the authors urge widespread use of intraoperative sonography in patients with spinal dysraphism and syringohydromyelia.

Humans