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Biomedical subjects

K Pojunas

Publications and source records attributed to K Pojunas.

8 recordsLinked to original sources
PubMed1987

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↗
PubMed1987

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↗
PubMed1986

Anterior commissure: anatomic-MR correlation and use as a landmark in three orthogonal planes.

Correlation of cryomicrotomic and myelin-stained sections of human cadaver heads with spin-echo magnetic resonance (MR) images documents that MR imaging routinely displays the anterior commissure in three orthogonal planes as a distinct white-matter tract that resembles bicycle handlebars. The anterior commissure crosses the midline at the upper end of the lamina terminalis, just anterior to the anterior columns of the fornices. To each side of midline, it curves antero-inferolaterally and then postero-inferolaterally through the lateral nucleus of the globus pallidus to course with the white matter of the external and extreme capsules toward the middle and inferior temporal gyri. Because the anterior commissure is easily recognizable in all three planes at differing pulse sequences, the commissure has proved to be a major landmark for identification of the complex anatomy of this region, especially in sagittal sections.

Brain↗
PubMed1985

Magnetic resonance imaging of the cavernous sinus.

The magnetic resonance (MR) appearance of the cavernous sinus was studied by correlating the MR images of normal volunteers and cryomicrotomic sections from six cadavers. In addition, MR images of patients with parasellar masses were compared with corresponding intravenously enhanced computed tomographic (CT) scans. The MR appearance of the cranial nerves in the cavernous sinuses is demonstrated, as well as MR signs of a parasellar mass, including obliteration of intracavernous venous spaces, displacement of the intracavernous internal carotid artery, and bulging of the lateral wall of the cavernous sinus. MR proved to be more effective than CT in delineating the parts of the cavernous sinus.

Aneurysm↗
PubMed1985

Orbital apex: correlative anatomic and CT study.

A detailed analysis of the coronal anatomic and CT appearances of the orbital apex is presented. In cadavers, coronal CT 9800 scans of the orbital apex and precisely corresponding cryomicrotomic sections were obtained. The CT appearance of the optic nerve, anulus of Zinn, and cranial nerves III-VI at the superior orbital fissure and orbital apex were determined. These anatomic structures were also demonstrated in clinical CT studies. Practical applications of the anatomic landmarks in evaluating orbital apex tumors are illustrated.

Cadaver↗
PubMed1984

Syringomyelia and hydromyelia: magnetic resonance evaluation.

Magnetic resonance (MR) imaging of 13 proved cases of syringomyelia or hydromyelia and one case of myelomalacia is described. Most intramedullary cysts were evident on sagittal partial saturation recovery (PSR) images. One cyst containing viscous fluid was not demonstrated on PSR images, but was suggested on a sagittal spin echo image. The case of myelomalacia was indistinguishable from a syrinx on axial PSR and spin echo images. Not all cases of syringomyelia and hydromyelia had the typical MR appearance previously described in the literature. Atypical cysts, spinal cord degeneration, and tumors may have a similar appearance on MR.

Cysts↗
PubMedDate not supplied

CT appearance of hemangiopericytoma.

Hemangiopericytoma is an uncommon tumor that may occur anywhere in the body but is most often found in the retroperitoneum, extremities, and nasopharynx. The CT evaluation of five malignant hemangiopericytomas (two retroperitoneal, two nasopharyngeal, one thigh) revealed speckled calcifications in all cases. The lesions in the retroperitoneum and thigh were large and lobular, with areas of cystic-degeneration or hemorrhage. Computed tomography of a rare, benign osseous hemangiopericytoma demonstrated characteristics of a slow-growing bone tumor with a cortical break in the proximal femur. The homogeneously enhancing, noncalcified mass found in the posterior fossa appeared similar to the typical benign hemangiopericytoma reported in this location by other authors.

Adolescent↗