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Biomedical subjects

E L Kier

Publications and source records attributed to E L Kier.

At least 19 recordsLinked to original sources
PubMed2000

MR imaging and histologic features of subinsular bright spots on T2-weighted MR images: Virchow-Robin spaces of the extreme capsule and insular cortex.

PURPOSE: To determine the cause and frequency of high-signal-intensity foci detected in the insular cortex and extreme capsule on thin-section, high-spatial-resolution, coronal, T2-weighted magnetic resonance (MR) images. MATERIALS AND METHODS: The authors assessed high-signal-intensity areas in the insular cortex and extreme capsule on coronal MR images obtained in 56 patients with seizure and five control subjects. Images were obtained with thin-section, high-spatial-resolution, T2-weighted, fast spin-echo; three-dimensional, spoiled gradient-recalled-echo; and fluid-attenuated inversion-recovery sequences. In two formalin-fixed brain specimens, MR imaging findings were correlated with gross anatomic and histologic findings. RESULTS: Subinsular bright spots were found in 53 of the 56 (95%) patients (96 of 112 [86%] hemispheres) and all five control subjects. The spots were elliptical in 30 patients, round in 14 patients, linear in 22 patients, and dotlike in seven patients and often had a featherlike configuration. The spots were isointense to cerebrospinal fluid on T2-weighted, fast SE images and were located in the anterior extreme capsule white matter and insular cortex. MR imaging of brain specimens revealed bilateral elliptical areas of high signal intensity that corresponded to small multiple cavities at gross anatomic inspection. At microscopic examination, these cavities were perivascular spaces of mostly arteriolar origin. CONCLUSION: High-signal-intensity subinsular foci at MR imaging are due to enlarged perivascular spaces. In most cases, these foci can be visualized on thin-section, high-spatial-resolution, coronal T2-weighted images; they should not be mistaken for pathologic conditions when they occur unilaterally.

Adolescent↗
PubMed1997

Embryology of the human fetal hippocampus: MR imaging, anatomy, and histology.

PURPOSE: To identify changes in the embryology of the hippocampus responsible for its adult anatomy. METHODS: Ten human fetal specimens ranging from 13 to 24 weeks' gestational age were examined with MR imaging. Dissections and histologic sections of 10 different specimens of similar ages were compared with MR imaging findings. RESULTS: At 13 to 14 weeks' gestation, the unfolded hippocampus, on the medial surface of the temporal lobe, surrounds a widely open hippocampal sulcus (hippocampal fissure). At 15 to 16 weeks, the dentate gyrus and cornu ammonis have started to infold. The hippocampal sulcus remains open. The parahippocampal gyrus is larger and more medially positioned. The CA1, CA2, and CA3 fields of the cornu ammonis are arranged linearly. The dentate gyrus has a narrow U shape. By 18 to 20 weeks, the hippocampus begins to resemble the adult hippocampus. The dentate gyrus and cornu ammonis have folded into the temporal lobe. The hippocampus and subiculum approximate each other across a narrow hippocampal sulcus. The CA1-3 fields form an arc and the CA4 field has increased in size within the widened arch of the dentate gyrus. CONCLUSION: MR imaging of fetuses provides a developmental basis for understanding hippocampal anatomy.

Adult↗
PubMed1997

The lamina rostralis: modification of concepts concerning the anatomy, embryology, and MR appearance of the rostrum of the corpus callosum.

PURPOSE: To study the anatomy and embryology of the lamina rostralis, and to determine whether the rostrum is, as frequently stated, the last section of the corpus callosum to develop. METHODS: The rostrum was analyzed in dissected adult brains and on MR studies in 300 patients with a normal corpus callosum and in 84 patients with a hypogenetic corpus callosum. MR images of intact fetuses and photographs of dissected fetal and adult vertebrate brains were also analyzed. RESULTS: The rostrum extends from the genu to the upper end of the lamina terminalis and consists of two sections: a thick beaked segment and the thin lamina rostralis, which blends posteriorly with the lamina terminalis. During fetal development the lamina rostralis changes from a semivertical to a semihorizontal orientation. Many hypogenetic corpora callosi have a semivertical lamina rostralis. A rudimentary beaked segment can be present without a normal genu. CONCLUSIONS: The rostrum is not the last segment of the corpus callosum to develop. Rather, the lamina rostralis segment of the fetal rostrum is already present before the genu and splenium develop. Additionally, the beaked segment of the rostrum develops concurrently with maturation of the genu.

Adult↗
PubMed1996

Detection of nerve rootlet avulsion on CT myelography in patients with birth palsy and brachial plexus injury after trauma.

OBJECTIVE: Recent advances in neurosurgical treatment of traumatic and birth-related brachial plexus injuries require differentiation of preganglionic nerve rootlet avulsion from postganglionic lesions. The purpose of this study was to evaluate the efficacy of thin-section high-resolution CT myelography for revealing cervicothoracic nerve rootlet avulsion in patients with brachial plexus injuries before surgery. MATERIALS AND METHODS: We evaluated eight patients with posttraumatic or birth-related brachial plexus injury on cervical plain film myelography and high-resolution CT myelography before surgical exploration and repair. CT myelograms were retrospectively evaluated for nerve rootlet avulsion, traumatic pseudomeningocele, and deformity of the subarachnoid space. Results were correlated with surgical exploration and intraoperative somatosensory evoked potentials. RESULTS: Seventy-two (95%) of 76 imaged cervicothoracic levels were adequately shown on CT myelography. Nerve rootlet avulsion, or preganglionic disruption, was shown at 21 levels. Associated pseudomeningocele, or deformity of the subarachnoid space, was seen at 12 (57%) of the 21 avulsion levels. Surgical exploration and intraoperative somatosensory evoked potentials showed complete preganglionic nerve rootlet avulsion at 22 levels. One of the complete avulsions revealed by surgery was not included on the patient's CT myelogram. Of the 21 imaged levels, 20 were correctly revealed on CT myelography (95% sensitivity, 98% specificity). At surgery, partial nerve rootlet avulsion was found at three other levels. None of the partial avulsions was correctly identified on the CT myelograms. CONCLUSIONS: High-resolution CT myelography with thin contiguous axial section is sensitive for revealing complete nerve rootlet avulsion in patients with brachial plexus birth palsies and brachial plexus injuries after trauma. Preoperative CT myelography in these patients allows a more complete injury evaluation for accurate prognosis and surgical planning.

Adolescent↗
PubMed1996

The normal and abnormal genu of the corpus callosum: an evolutionary, embryologic, anatomic, and MR analysis.

PURPOSE: To define the normal and abnormal genu of the corpus callosum by examining its evolution and embryology and by analyzing its normal and abnormal appearance on MR images. METHODS: A reference line was drawn from the mamillary body through the anterior commissure and corpus callosum-the MAC line. This line was used to evaluate the genu in adult mammal brains, in human fetal brains, on MR images of 1800 patients with normal corpora callosi, and on MR images of 113 patients with callosal anomalies. RESULTS: In primates, increased frontal lobe size is associated with an anteriorly shifted genu. In human fetal development, the anterior body of the corpus callosum develops before the definitive genu. The normal human genu always projects in front of the MAC line. In none of the 113 patients with callosal anomalies was there only a normal genu. CONCLUSIONS: The human corpus callosum develops bidirectionally, not from front to back. The MAC line is a useful frame of reference to study the evolution and embryology of the genu and to distinguish the normal from the abnormal genu of the human corpus callosum.

Adult↗
PubMed1995

Limbic lobe embryology and anatomy: dissection and MR of the medial surface of the fetal cerebral hemisphere.

PURPOSE: To facilitate understanding of limbic lobe anatomy by showing embryologic transformations of the medial surface of the cerebral hemisphere. METHODS: Brains from fetal specimens ranging from 13 to 24 weeks of gestational age were dissected. Photographs were made of the medial surface of the cerebral hemisphere. MR images of different fetal specimens of similar age were made for comparison of MR anatomy with dissected material. RESULTS: At 13 weeks, the entire inner limbic arch of the hippocampal formation is visible on the medial surface of the cerebral hemisphere. The hippocampal sulcus extends from frontal lobe to temporal lobe. At 16 weeks, the outer neocortical limbic arch of the subcallosal area, cingulate gyrus, and parahippocampus gyrus is present. Growth of the corpus callosum is associated with reduction in size of the hippocampal formation in the frontal lobe. The sulcus of the corpus callosum is the remnant of the anterior part of the hippocampal sulcus. At 18 weeks, growth of the parahippocampal gyrus begins to conceal the hippocampal formation. The supracallosal gyrus (indusium griseum), hidden from view by the corpus callosum, and the paraterminal gyrus are remnants of the previously larger hippocampal formation. CONCLUSIONS: Analysis of fetal specimens in different developmental stages with dissection and MR provides insight into embryologic transformations responsible for the complex anatomy of the limbic lobe.

Fetus↗
PubMed1985

Intraventricular hemorrhage in a term neonate secondary to a third ventricular AVM. Case report.

An initially healthy infant born of an uncomplicated full-term gestation was brought for evaluation of the acute onset of vomiting, irritability, lethargy, and opisthotonus at 14 days of age. Computerized tomography demonstrated an intraventricular hemorrhage. Arteriography defined an angioma on the roof of the third ventricle which was successfully removed via the transcallosal interfornicial approach on the 34th day of life. Other than an easily controlled seizure disorder, the postoperative course was uneventful. At 8 months of age the child is developing normally. Arteriovenous malformations should be considered in the differential diagnosis of intraventricular hemorrhage in full-term neonates without predisposing trauma or bleeding diathesis. High-speed digital subtraction arteriography may be used to screen for this diagnosis. The transcallosal interfornicial exposure offers a satisfactory approach for excising third ventricular angiomas in young infants.

Cerebral Hemorrhage↗
PubMed1983

High resolution computed tomography of the osseous external auditory canal: 1. Normal anatomy.

This study of 34 normal ears was conducted in order to define more precisely the normal computed tomographic (CT) anatomy of the osseous external auditory canal. Great variability was found in canal configuration and its relationship to the temporal squama. The understanding of normal CT appearance of the various fissures along the anterior wall of the external canal is important to avoid mistaking fissures for fractures.

Adolescent↗
PubMed1983

The choice of contrast agent for myelography in patients with nonpenetrating cervical spine trauma.

Forty patients with neurological deficits from cervical spine trauma had cervical myelography with metrizamide, gas, iophendylate, or a combination thereof. At a low dosage (less than or equal to 1.25 g I), metrizamide was found to be not only the most effective in demonstrating the spinal cord but also safe if used with a C-arm biplane fluoroscopic unit which has tomographic capability.

Adolescent↗
PubMed1983

Temporal bone disease: a comparison between high resolution computed tomography and pluridirectional tomography.

Sixty-five patients with suspected ear disease were examined with CT, and abnormalities were detected in 42 of them; 58 of these patients also had pluridirectional tomographic examinations. Eighteen of the patients in whom abnormalities were detected underwent exploratory surgery. CT was useful in the diagnosis of tympanic membrane swelling, fluid in the middle ear, cholesteatoma, granulation tissue, and adhesions. The superior contrast resolution of CT allowed for the visualization of ossicles when they were surrounded by an inflammatory mass or by blood. In trauma cases, axial images facilitated visualization of longitudinal fractures, which frequently pass through the geniculate ganglion of the facial nerve. CT and pluridirectional tomography were comparable in the demonstration of disease that involved the mastoid air cells, although fluid in air cells was more easily demonstrated by CT. Pluridirectional tomography was superior to CT in the demonstration of bone destruction; CT, however, was more sensitive in the diagnosis of lateral semicircular canal fistula. Based on this analysis, we recommend that these two modalities be used in a complementary fashion to evaluate suspected middle ear disease.

Child↗
PubMed1983

Pulsatile tinnitus arising from jugular megabulb deformity: a treatment rationale.

Pulsatile tinnitus is a rare presenting symptom in patients with enlarged jugular bulbs. We will describe three young women presenting with right pulsatile tinnitus associated with a megabulb deformity of the temporal bone. After extensive radiologic and audiologic evaluation, no vascular or bony abnormalities could be identified. All three patients demonstrated pulsatile bruits over the right temple. Pulsatile tinnitus disappeared with ipsilateral jugular compression suggesting flow rather than pressure to be responsible for abnormal auditory symptoms. This observation formed the basis of our treatment recommendations. Because of progressively debilitating pulsatile tinnitus, two patients elected right internal jugular vein ligations under local anesthesia. Both patients were relieved of tinnitus. We conclude that jugular vein ligation can be a safe and effective surgical treatment for pulsatile tinnitus resulting from a jugular megabulb deformity, provided two criteria are met: 1. The presence of an expanding tumor is ruled out. 2. The presence of contralateral venous drainage is established by angiography or brain scan. Anatomic and functional hemodynamic considerations of brain circulation will be emphasized in the discussion of our treatment rationale.

Adult↗
PubMed1982

The role of high resolution computed tomography in evaluating disease of the middle ear.

Successful temporal bone imaging demands appropriate modifications of the computed tomography (CT) scanner. While CT has been shown to be useful for demonstrating the detailed anatomy of the temporal bone, its role in the evaluation of middle ear pathology has not been investigated. Selective cases are presented to highlight the advantages of CT. Computed tomography is excellent in demonstrating soft tissue masses in the middle ear in inflammatory disease. It is also useful in accurately localizing bony fragments in trauma, as well as determining the status of the ossicles. Disease solely involving the tympanic membrane can be diagnosed on CT without subjecting the patient to surgical exploration.

Adult↗