ZIB

Hits per page

hits 1 - 2 | 2 hits

Sorting

Electronic Resource

The sphenoid sinus during childhood: establishment of normal developmental standards by MRI (1994)

Szolar, D ; Preidler, K ; Ranner, G ; [et al.]

Springer

Surgical and radiologic anatomy 16 (1994), S. 193-198

add to mindlist on the mindlist

Details

ISSN: 1279-8517

Keywords: Paranasal sinuses, anatomy ; Paranasal sinuses, childhood ; Paranasal sinuses, MR-Imaging ; Sphenoid bone

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine

Description / Table of Contents: Résumé Afin de démontrer les aspects fondamentaux du développement du sinus sphénoïdal pendant l'enfance, nous avons revu l'aspect en IRM du sinus sphénoïdal de 401 patients agés de moins de 15 ans. L'étude de la moelle osseuse, le développement de la pneumatisation, la croissance et le cloisonnement du sinus sphénoïdal ont été explorés en séquences pondérées en T1 et en T2. Le sinus sphénoïdal se présente, en séquence pondérée en T1, avec un signal faible et uniforme (moelle osseuse rouge) chez tous les enfants agés de moins de 4 mois. Ce signal hypo-intense devient hyper-intense (transformation de la moelle osseuse) à partir du 4 ème mois. Le début de la pneumatisation est noté à 13–15 mois. A l'âge de 43–48 mois, la partie antérieure du sinus sphénoïdal est pneumatisée chez 85 % des enfants. La pneumatisation est complète chez tous les patients agés de plus de 10 ans. La croissance dans chaque direction de l'espace est caractéristique. L'apparition d'un septum médian est observée à une fréquence variable par tranche d'âge, avec un maximum de 77 %. Les variations existent dans 4,5 % à 20 % des cas. La connaissance de ce phénomène peut servir de référence pour évaluer le développement normal et anormal du sinus sphénoïdal et être d'un grand intérêt dans le diagnostic et le traitement des affections du sinus sphénoïdal et des régions voisines chez l'enfant.

Notes: Summary To obtain baseline standards of normal age-related development of the sphenoid sinus during childhood magnetic resonance images of the sphenoid sinus in 401 patients less than 15 years old were reviewed. T1-weighted sagittal and T2-weighted axial scans were evaluated for bone marrow conversion, development of pneumatization, spatial enlargement and septation of the sphenoid sinus. The sphenoid sinus had a uniformely low signal intensity (red bone marrow) on T1-weighted images in all children less than 4 months old. Signal intensity changes from hypo- to hyperintense (bone marrow conversion) started at age of 4 months. Onset of pneumatization was observed in 12% of the patients at age 13–15 months. By age 43–48 months, 85% of the patients showed pneumatization of the anterior part of the sphenoid bone. Pneumatization was complete in all patients older than 10 years. Enlargement of the sinus showed a characteristic profile in each dimension. Median septation was observed irregularly with age, with a maximum of 77%. Septum variants were noticed between 4.5% and 20%. The recognition of this phenomenon may serve as a reference for evaluating normal and abnormal development of the sphenoid sinus and may be of great value for diagnostic and therapeutic management of pathologic conditions of the child's sphenoid sinus and its surrounds.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01627594

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

Flow behavior of symmetrical P (S-b-MMA) block copolymers: Rheological problems arising from shear modified morphology (1993)

Braun, H. ; Gleinser, W. ; Cantow, H.-J.

New York, NY [u.a.] : Wiley-Blackwell

Journal of Applied Polymer Science 49 (1993), S. 487-499

add to mindlist on the mindlist

Details

ISSN: 0021-8995

Keywords: Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics

Notes: In this article, symmetrical, narrow distribution P (S-b-MMA) block copolymers are characterized rheologically, using a dynamic spectrometer and a stress rheometer. The shear induced morphology changes are investigated by off-line electron microscopy and SAXS. We tried to correlate the results of dynamics and long-time creep experiments with morphological and rheological features. Summarizing, one can point out that the examined block copolymers reveal the well-known low frequency behavior of phase separated blends. Additionally, we observed a significant shear influence on the morphology, i.e. a shear induced structuring and alignment of lamellae. This considerable change in morphology is also reflected by the characteristic rheological properties (retardation time, yield stress). Therefore, problems concerning the validity range of linear viscoelastic behavior arise, which are discussed in brief. © 1993 John Wiley & Sons, Inc.

Additional Material: 9 Ill.