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H Hees

Publications and source records attributed to H Hees.

14 recordsLinked to original sources
PubMed2001

Comparison of 2-D turbo spin echo and 3-D gradient echo sequences for the detection of the trigeminal nerve and branches anatomy.

The aim of this study was to assess the detectability of the trigeminal nerve and its branches using T1 weighted (w.) 3-D magnetization prepared rapid gradient echo (MP-RAGE), T2* w. 3D CISS and T2 w. 2-D turbo spin echo MR sequences. Thirty healthy volunteers were examined for this purpose using a 1.5 Tesla MR unit. The detectability of the trigeminal nerve and Gasser's Ganglion, i.e. structures that are surrounded by liquor was best using 3-D CISS. In the case of the ophthalmic, maxillary and mandibular nerves, the T1 w. 3-D MPRAGE was significantly better than T2* w. CISS and T2 w. 2-D turbo spin echo. The latter yielded the poorest results. We conclude that both high resolution T2* w. and T1 w. 3-D sequences are necessary in order to detect the liquor-surrounded trigeminal nerve and its soft tissue-surrounded branches. We would therefore recommend the inclusion of constructive interference in steady state (CISS) and MP-RAGE in a MR imaging protocol of the trigeminal nerve and its branches.

Adult↗
PubMed2000

MRI detection of olfactory bulb and tract.

Thirty healthy volunteers underwent MRI with 3D MP-RAGE, 3D CISS and 2D turbo spin echo sequences to compare the detectability of olfactory fibers, bulb, tract, and sulcus. The overall detectability was slightly better using MP-RAGE compared with CISS. Both 3D sequences were superior to 2D turbo spin echo. We therefore recommend including the MP-RAGE sequence in an MR imaging protocol of the olfactory nerve.

Adolescent↗
PubMed2000

Comparison of a T2* w. 3D CISS and a T2 w. 3D turbo spin echo sequence for the anatomical study of facial and vestibulocochlear nerves.

Thirty healthy volunteers were examined with a T2* w. 3D CISS and a T2 w. 3D turbo spin echo (TSE) sequence in order to compare the facial and vestibulocochlear nerve detectability in the cerebellopontine angle and the internal auditory canal. CISS was significantly better than 3D TSE for nerve detectability in the cerebellopontine angle and equally as good as 3D TSE in the internal auditory canal. We would therefore recommend the inclusion of CISS in an MR imaging protocol of the facial and vestibulocochlear nerves.

Adolescent↗
PubMed1999

The Chievitz juxtaparotid organ.

The Chievitz juxtaparotid organ represents a macroscopic longitudinal formation, which is developed from oral cavity ectoderm in its lateral wall. As to its function, the organ probably represents a mechanosensor with different qualities of perception. The information coming from its sensors takes part in different activities of the lateral wall of oral cavity during sucking, swallowing, mastication, speech, protecting reflexes and wall tonus. The Chievitz juxtaparotid organ is not only a morphologically interesting structure, but is of great importance also for clinic and surgical pathology of the oral cavity.

Cheek↗
PubMed1993

[Variations in the thyreocervical trunk].

Variations in the vascular system are much more numerous than in other anatomical structures. The knowledge of these variations is essential for radiologists and surgeons in the interpretation of angiograms. A complex variation of the thyreocervical trunk is presented in this paper: The Aa. thoracica interna and cervicalis profunda arises from the truncus which perforates the anterior scalenic muscle.

Animals↗
PubMed1990

[Vascular morphology of the bovine testis. Light and scanning electron microscopic studies].

The testicular artery of the bull-testis shows a straight course from the end of the pampiniform plexus to the caudal extremity of testis. There it branches off in Rami tunicales, which lie as stratum arteriosum superficially to the albugineal veins of testis: a multi-layered stratum venosum. Arterial Rami parenchymales centripetales run directly to the mediastinum testis, form coils and then divide in approximately 10 or more thinner Rami parenchymales centrifugales, which extend from the coils into the parenchyma of the gonad. The three-dimensional microvasculature of the bull-testis is strikingly different from that of rodents: The peritubular network of capillaries in the interstitial space is positioned in a more irregular way. Only here and there is discernible a rope-ladder-like or polygonal arrangement of capillaries. A subalbugineal plexus does not exist in the bovine testis. Parenchymal veins drain in albugineal veins and these empty in the venous networks of the pampiniform plexus. Valves are a rare finding in testicular veins. Already low perfusion-pressure easily forces the corrosion-compound to leave the capillary bed and form typical extravasations as bent shovel-like plates, thus filling the clefts of peritubular spaces. Arteries and veins are directly embedded in the parenchyma of testis, surrounded only by a relatively thin margin of perivascular connective tissue. There are no septula testis and therefore a lobular organisation of bovine testis does not exist. The angioarchitecture of the testis plays an important role in thermoregulatory and androgen-transfer mechanisms as well as in the transport of rete-fluid to the epididymis.

Animals↗
PubMed1989

The mediastinum of the bovine testis.

The bovine testis has a central mediastinum consisting of longitudinally oriented rete channels and spacious lymph vessels, embedded in the mediastinal stroma. The latter represents a contractile-elastic unit and is composed of myofibroblasts, collagen bundles and accumulations of elastin, connecting the myofibroblasts. The dimension of the mediastinum varies in cross sections at different levels between 3.5 and 31.8 mm2. In one cross section approximately 30 rete channels and approximately 30 openings of straight testicular tubules are encountered. Nearly 25% of the area is occupied by thin-walled, valveless lymph vessels. Arterial convolutes, interpolated between straight centripetal and straight centrifugal branches of the testicular artery flank the rete on all sides. It is concluded that the pulsation within these convolutes together with the contractile-elastic stroma promotes lymph and rete content in a caudo-cranial direction. Chordae retis as described by Roosen-Runge and Holstein (1978) for the human testis are a common feature in the bovine mediastinum testis. The rete channels are lined by a simple cuboidal or columnar epithelium. Short intraepithelial crypts are present and function as epithelial reserve for dilatation and expansion of the rate. The inventory of organelles is rather inconspicuous in the rete epithelium. The apical border bears short microvilli and gives a strong reaction for alkaline phosphatase. The basal cytoplasm contains many small to medium-sized electron-dense bodies and is site of a strong acid phosphatase reaction. The rete epithelium as a whole reacts strongly with leucine aminopeptidase, the marker enzyme of the testicular excurrent duct system. Many free mononuclear cells, mostly macrophages, are observed in the basal half of the rete epithelium.

Animals↗
PubMed1987

Spatial topography of the excurrent duct system in the bovine testis.

The rete testis of the bull is situated within an axial mediastinum and consists of approximately 30 longitudinally arranged, anastomosing rete channels. At the cranial testicular pole all rete channels empty into a common space, the area confluens retis, which is subdivided by small septa and narrow chordae retis. The area confluens always contains numerous spermatozoa and is connected with the bulbous initial portions of the efferent ductules by short, often tortuous rete tubules. Since the connection between rete and efferent ductules is situated within the tunica albuginea, the bovine excurrent duct system is not provided with an extratesticular rete as in many other mammals. Straight testicular tubules merge from all directions to connect with superficial rete channels, but the inlets are not evenly distributed. In the periphery each straight tubule begins with a cup-like structure followed by a narrow stalk region and a heavily folded portion opening either immediately into a rete channel or into a tube-like lateral rete extension. In close contiguity to the rete testis lie extremely coiled arterial portions connecting the centripetal and the centrifugal branches of the testicular artery. Since intrinsic musculature is scarcely developed in the mediastinum, and transport of rete content relies primarily on massage due to external pressure changes, the pulsatile blood flow through these coiled arteries may influence conveyance processes within the rete testis. An intimate spatial association between area confluens retis and adjacent large, thin-walled lymph vessels may facilitate a transfer of androgens into the fluid of the rete testis.

Animals↗
PubMed1984

Vascular morphology of the bovine spermatic cord and testis. I. Light- and scanning electron-microscopic studies on the testicular artery and pampiniform plexus.

This highly coiled testicular artery within the bovine spermatic cord has a constant luminal diameter but a continuously decreasing mural thickness. The pampiniform plexus is composed of three interconnected venous networks differing in mesh sizes and calibres. The large veins of the first network display pouches and permanent constrictions, which may serve as throttle devices. The constitutents of the third network are venules or venous capillaries with diameters between 10 and 20 micron; they favor a periarterial position or even occupy the media-adventitia border of the testicular artery. All plexus veins are devoid of valves. The existence of true arteriovenous anastomoses between smaller branches of the testicular artery and plexus veins was established by serial sections. The vascular morphology of the spermatic cord is discussed with special attention to a postulated venous-arterial steroid transfer in this region.

Animals↗
PubMedDate not supplied

Pregnancy-induced structural changes and trophoblastic invasion in the segmental mesometrial arteries of the guinea pig (Cavia porcellus L.).

Light microscopic, electron microscopic and histochemical studies were carried out on the segmental mesometrial arteries of non-pregnant guinea pigs and on pregnant ones at each of the nine weeks of gestation. Pregnant animals show drastic changes in arterial structure and dimensions. Hypertrophy and structural dilatation of the arterial wall are obvious. In midpregnancy, the elastic membranes begin to disappear; only small fragments remain. From the fifth week on, mononuclear cells appear in the media; they form aggregates and occasionally giant cells with signs of phagocytosis in the seventh week of gestation. In the eighth week further degenerative changes can be observed, resulting in widespread destruction of the arterial wall. Deposition of necrotic cell debris is obvious in the ninth week. By this time there appear in the endothelial layer conspicuous single cells, cell aggregates and giant cells with heavily folded nuclei, prominent nucleoli, abundant vesicles, free ribosomes, intracellular lacunae and the histochemical properties of placental trophoblast. These cells in the endothelium are distinctly different from the medial giant cells of mononuclear origin. According to these observations, the segmental mesometrial arteries of pregnant guinea pigs show cytological and structural changes similar to those described for the mesometrial arteries in the hamster and the spiral arteries in man. The results show that, beside structural dilatation, degenerative changes and apparent trophoblastic giant cell invasion occur in the arteries studied. Trophoblastic invasion occurs later than structural dilatation and obviously does not trigger or control the structural dilatation of the segmental mesometrial arteries.

Animals↗
PubMedDate not supplied

Comparison of 2D and 3D MRI of the optic and oculomotor nerve anatomy.

A total of 30 healthy volunteers underwent magnetic resonance imaging (MRI) with T1 weighted (w.) 3D magnetization prepared rapid gradient echo (MP-RAGE), T2 w. 2D turbo spin echo (TSE) and T2* w. 3D constructive interference in steady state (CISS) sequences to evaluate the detectability of the optic, oculomotor, trochlear and abducens nerves. CISS yielded the best results for the trochlear and abducens nerve, MP-RAGE for the optic chiasm and tract. The optic and oculomotor nerves were very well detectable using both CISS and MP-RAGE without any statistically significant difference between the two.

Abducens Nerve↗