PitSurgRT: real-time localization of critical anatomical structures in endoscopic pituitary surgery.

PURPOSE: Endoscopic pituitary surgery entails navigating through the nasal cavity and sphenoid sinus to access the sella using an endoscope. This procedure is intricate due to the proximity of crucial anatomical structures (e.g. carotid arteries and optic nerves) to pituitary tumours, and any unintended damage can lead to severe complications including blindness and death. Intraoperative guidance during this surgery could support improved localization of the critical structures leading to reducing the risk of complications. METHODS: A deep learning network PitSurgRT is proposed for real-time localization of critical structures in endoscopic pituitary surgery. The network uses high-resolution net (HRNet) as a backbone with a multi-head for jointly localizing critical anatomical structures while segmenting larger structures simultaneously. Moreover, the trained model is optimized and accelerated by using TensorRT. Finally, the model predictions are shown to neurosurgeons, to test their guidance capabilities. RESULTS: Compared with the state-of-the-art method, our model significantly reduces the mean error in landmark detection of the critical structures from 138.76 to 54.40 pixels in a 1280 × 720-pixel image. Furthermore, the semantic segmentation of the most critical structure, sella, is improved by 4.39% IoU. The inference speed of the accelerated model achieves 298 frames per second with floating-point-16 precision. In the study of 15 neurosurgeons, 88.67% of predictions are considered accurate enough for real-time guidance. CONCLUSION: The results from the quantitative evaluation, real-time acceleration, and neurosurgeon study demonstrate the proposed method is highly promising in providing real-time intraoperative guidance of the critical anatomical structures in endoscopic pituitary surgery.

The "candy wrapper" of the pituitary gland: a road map to the parasellar ligaments and the medial wall of the cavernous sinus.

PURPOSE: The anatomy of the medial wall of the cavernous sinus (MWCS) and parasellar ligaments (PLs) has acquired increasing importance in endoscopic endonasal (EE) surgery of the cavernous sinus (CS), including resection of the MWCS in functioning pituitary adenomas (FPAs). Although anatomical studies have been published, it represents a debated topic due to their complex morphology. The aim is to offer a description of the PLs that originate from the MWCS and reach the lateral wall of the cavernous sinus (LWCS), proposing the "candy wrapper" model. The relationships between the neurovascular structures and histomorphological aspects were investigated. METHODS: Forty-two CSs from twenty-one human heads were studied. Eleven specimens were used for EE dissection; five underwent a microscopic dissection. Five specimens were used for histomorphological analysis. RESULTS: Two groups of PLs with a fan-shaped appearance were encountered. The anterior group included the periosteal ligament (55% sides) and the carotico-clinoid complex (100% sides), formed by the anterior horizontal and the carotico-clinoid ligaments. The posterior group was formed by the posterior horizontal (78% sides), and the inferior hypophyseal ligament (34% sides). The periosteal ligament originated inferiorly from the MWCS, reaching the periosteal dura. The anterior horizontal ligament was divided in a superior and inferior branch. The superior one continued as the carotid-oculomotor membrane, and the inferior branch reached the CN VI. The carotico-clinoid ligament between the middle and anterior clinoid was ossified in 3 sides. The posterior horizontal ligament was related to the posterior genu and ended at the LWCS. The inferior hypophyseal ligament followed the homonym artery. The ligaments related to the ICA form part of the adventitia. CONCLUSION: The "candy wrapper" model adds further details to the previous descriptions of the PLs. Understanding this complex anatomy is essential for safe CS surgery, including MWCS resection for FPAs.

Cytodifferentiation of Wulzen's cone of mature male sheep hypophysis cerebri with special emphasis on its parenchymal correlations with the adjacent pars distalis, pars intermedia and pars nervosa.

Background: Hypophysis cerebri is considered the master endocrine gland as it plays a critical role in influencing and controlling the vitality of other endocrine organs via several hormones secretion. Aim: The present study was performed to clarify the localization of Wulzen's cone (WC) within sheep hypophysis and cytodifferentiation of the glandular cells filling cone parenchyma with particular emphasis on the cone correlations with adjacent pars distalis (pd), pars intermedia (pi), and pars nervosa (pn). Methods: Pituitaries were collected and processed histologically, then subjected to different combinations of special stains; Br-AB- OFG., PFA-AB-PAS-OG., PAS-Orange G., Orange G- Acid Fuchsin- Light Green, Bielschowsky technique, Masson's trichrome & Gomori's reticulin. Results: A sagittal section through the pituitaries revealed a well-developed cone of glandular cells protruding from the pi like a tongue plate towards the hypophyseal cleft in the neighborhood of the pd and behind the pn. Resembling the pd, various glandular cells were distinguished in the cone; chromophobes and chromophils of acidophils & basophils. The cone is mainly formed from acidophils intermingled with the chromophobes. Meanwhile, basophils were primarily localized at the most anterior & posterior parts of the cone. In front of the cone, pd were localized, resembling a wing-shaped and filled with several categorized glandular cells; chromophobes and chromophils. Upper to the cone, pi were localized and composed mainly of weakly basophilic cuboidal or polygonal cells arranged in parallel cords or follicles. Behind the cone, pn was localized as a ventral outpouching of the brain floor-like water drop. Unlike the cone, it was devoid of any glandular secretory cells or nerve cells but consisted mainly of unmyelinated nerve fibers, herring bodies, and pituicytes. Conclusion: WC is present and well-developed in sheep adenohypophysis. Various glandular cells were distinguished, filling the cone, chromophobes, and chromophils of acidophils & basophils that were typically similar to the glandular cells of pd but with different distributions.

What to Do with Incidentally Discovered Pituitary Abnormalities?

Pituitary incidentalomas are discovered in approximately 10% to 40% of brain images. A complete patient history, physical examination, and dedicated pituitary function testing are needed, and subsequent results should lead to appropriate patient management. However, most lesions are asymptomatic pituitary adenomas or Rathke cleft cysts with a benign course. Many lesions can be clinically significant, including prolactinomas or other pituitary adenomas that warrant specific pituitary disease treatment. In other cases, mass effect causing visual compromise or refractory headache indicates a need for surgery. Here, various facets of a complex evaluation and treatment algorithm for pituitary incidentalomas are reviewed.

CD9-positive cells in the intermediate lobe of the pituitary gland are important supplier for prolactin-producing cells in the anterior lobe.

A supply of hormone-producing cells from stem/progenitor cells is critical to sustain the endocrine activity of the pituitary gland. In the adenohypophysis composing the anterior and intermediate lobe (AL and IL, respectively), stem/progenitor cells expressing sex-determining region Y-box 2 (SOX2) and S100ß are located in the marginal cell layer (MCL) facing Rathke's cleft (primary niche) and the parenchyma of the AL (secondary niche). Our previous studies using mice and rats indicated that the tetraspanin superfamily CD9 and CD81 are expressed in S100ß/SOX2-positive cells of primary and secondary niches (named CD9/CD81/S100ß/SOX2-positive cell), and the cells located in the AL-side niches exhibit plasticity and multipotency. However, it is unclear whether CD9/CD81/S100ß/SOX2-positive cells in the IL-side primary niche are stem/progenitor cells for the AL or IL. Here, we successfully isolated pure CD9/CD81/S100ß/SOX2-positive cells from the IL-side primary niche. They had a higher level of S100ß and SOX2 mRNA and a greater pituisphere forming capacity than those of CD9/CD81/S100ß/SOX2-positive cells isolated from the AL. They also had capacity to differentiate into all types of adenohypophyseal hormone-producing cells, concomitantly with the loss of CD9 expression. Loss of CD9 and CD81 function in CD9/CD81/S100ß/SOX2-positive cells by siRNA treatment impaired prolactin cell differentiation. Consistently, in the pituitary gland of CD9/CD81 double knockout mice, dysgenesis of the MCL and a lower population of prolactin cells were observed. These results suggest that the CD9/CD81/S100ß/SOX2-positive cells in the MCL of the IL-side are potential suppliers of adult core stem cells in the AL.

Surgical anatomy and nuances of the expanded endonasal transdorsum sellae and posterior clinoidectomy approach to the interpeduncular and prepontine cisterns: a stepwise cadaveric dissection of various pituitary gland transpositions.

BACKGROUND: Excelsior knowledge of endoscopic anatomy and techniques to remove the natural barriers preventing full endonasal access to the interpeduncular and prepontine cisterns determines the ease of transposing the pituitary gland (hypophysiopexy) preserving the glandular function without manipulating the optic apparatus and the oculomotor nerves. METHODS: Throughout stepwise cadaveric dissections, we describe the expanded endonasal approach (EEA) to the interpeduncular and prepontine cisterns with special references to the intricate anatomy of the region and techniques for hypophysiopexy and posterior clinoidectomies. CONCLUSION: This article illustrates sellar-diaphragmatic dural incisions and various "pituitary gland transpositions" techniques performed via extradural (lifting the gland still covered by both dural layers), interdural (transcavernous), and intradural (between the medial wall of the cavernous sinus and the pituitary tunica) to access the prepontine and interpeduncular cisterns.

Neuroimaging of the Pituitary Gland: Practical Anatomy and Pathology.

The pituitary gland is a small endocrine organ located within the sella turcica. Various pathologic conditions affect the pituitary gland and produce endocrinologic and neurologic abnormalities. The most common lesion of the pituitary gland is the adenoma, a benign neoplasm. Dedicated MR imaging of the pituitary is radiologic study of choice for evaluating pituitary gland and central skull region. Computed tomography is complimentary and allows for identification of calcification and adjacent abnormalities of the osseous skull base. This review emphasizes basic anatomy, current imaging techniques, and highlights the spectrum of pathologic conditions that affect the pituitary gland and sellar region.

The inferior intercavernous sinus: An anatomical study with application to trans-sphenoidal approaches to the pituitary gland.

OBJECTIVES: The inferior intercavernous sinus is located below the pituitary gland in the sella turcica. Its presence has been controversial among anatomists because it is not always found on radiological imaging or during cadaveric dissections; however, it is becoming a better-known structure in the neurosurgical and radiological fields, specifically with respect to transsphenoidal surgery. Therefore, the present study was performed to better elucidate this structure at the skull base. PATIENTS AND METHODS: Fifty adult, latex injected cadavers underwent dissection. The presence or absence of the inferior cavernous sinus was evaluated and when present, measurements of its width and length were made. Its connections with other intradural venous sinuses were also documented. RESULTS: An inferior intercavernous sinus was identified in 26 % of specimens. In all specimens, it communicated with the left and right cavernous sinus. The average width and length were 3 mm and 9.5 mm, respectively. In the sagittal plane, the inferior intercavernous sinus was positioned anteriorly in 31 %, at the nadir of the sella turcica in 38 %, and slightly posterior to the nadir of the sella turcica in 31 %. In two specimens (15.4 %), the sinus was plexiform in its shape. In one specimen a diploic vein connected the basilar venous plexus to the inferior intercavernous sinus on its deep surface. CONCLUSION: An improved understanding of the variable anatomy of the inferior intercavernous sinus is important in pathological, surgical, and radiological cases.

Variant sella morphology and pituitary gland height in adult patients with Chiari II malformation: potential pitfall in MRI evaluation.

PURPOSE: To systematically evaluate the sella morphology and pituitary gland height on brain MRI of Chiari II malformation (C2M) patients to understand the observed high incidence of apparent enlargement of the pituitary gland. METHODS: Brain MRIs of C2M patients at a single tertiary care adult institution were retrospectively reviewed. We also evaluated two age and gender-matched control groups-patients with normal brain MRI (C1 group) and chronic ventricular shunts (C2 group). The heights of tuberculum sella, dorsum sella, and pituitary gland were measured and compared. The presence or absence of dural thickening was noted. RESULTS: 21 patients were included in each group. In C2M group, a pituitary adenoma was suggested on 24% of the MRIs. The dorsum sella was significantly smaller in the C2M group (4.8 mm) compared to both the C1 group (7.4 mm, p < 0.001) and the C2 group (7.1 mm, p < 0.001). The pituitary gland was also larger in the cranial-caudal dimension in C2M group (8.6 mm) as compared to both the C1 group (6.6 mm, p < 0.01) and the C2 group (6.0 mm, p < 0.001). One C2M patient with a pituitary gland<10 mm was suggested to have a pituitary adenoma on outside MRI, although a normal pituitary gland was seen on pathology. CONCLUSION: C2M patients have shallow sella which can accentuate the pituitary gland height. The mean pituitary height was larger in C2M patients, but no functional pituitary pathology was present. It is important to consider sella morphology when evaluating the pituitary gland of C2M patients to avoid unnecessary medical and surgical interventions.

Tumor T2 signal intensity and stalk angulation correlates with endocrine status in pituitary adenoma patients: a quantitative 7 tesla MRI study.

PURPOSE: Pituitary adenomas are common CNS tumors that can cause endocrine dysfunction due to hormone oversecretion and by mass effect on the normal gland. The study of pituitary adenomas and adjacent sellar anatomy with high-resolution 7 T MRI may further characterize endocrine dysfunction. The purpose of this study was to determine the efficacy of 7 T MRI in identifying radiological markers for endocrine function. METHODS: MR images obtained in 23 patients with pituitary adenomas were reviewed by consensus between three neuroradiologists. Landmarks and criteria were devised to measure radiological features of stalk, tumor, and normal gland. Fischer's exact tests and nominal logistic regression were performed. RESULTS: Mean cross-sectional area of the stalk just below the infundibular recess was 6.3 ± 3.7 mm2. Mean curvature and deviation angles were 34.2° ± 23.2° and 29.7° ± 17.3°, respectively. Knosp scores obtained differed between 7 T and lower field strength scans (P < 0.0001 [right] and P = 0.0006 [left]). Ability to characterize tumor was rated higher at 7 T compared with lower field MRI, P = 0.05. Confidence in visualizing normal gland was also higher using 7 T MRI, P = 0.036. The six hormone-secreting tumors had higher corrected T2 mean SI than non-secreting tumors (2.54 vs. - 0.38, P = 0.0196). Seven patients had preoperative hypopituitarism and had significantly greater stalk curvature angles than patients without hypopituitarism (71.7° vs. 36.55°, P = 0.027). CONCLUSION: Radiological characterization of pituitary adenomas and adjacent native pituitary tissue may benefit with the use of 7 T MRI. Corrected T2 SI of tumor may be a sensitive predictor of hormonal secretion and may be useful in the diagnostic work-up for pituitary adenoma. 7 T MRI may be valuable in identifying markers of endocrine function in patients with pituitary adenomas. Our results indicate that hormone-secreting tumors have higher T2-weighted SI and tumors associated with preoperative hypopituitarism have greater stalk curvature angles.

Anatomic and histologic features of diaphragma sellae that effects the suprasellar extension.

This study aimed to determine the anatomical and histological features of diaphragma sellae that affect the suprasellar extension of intrasellar tumours. Twenty-four fresh adult cadavers were dissected for the study. Diaphragma sellae and pituitary capsules with sellar structures were resected. The diaphragma sellae was anatomically reviewed in detail. Immunohistochemical staining was performed for collagen types I, II, III, and IV. We examined the suprasellar growth of 13 sellar tumours extending superiorly through the diaphragma sellae by performing a series of 2704 endoscopic transnasal operations to analyse the anatomic and histologic results of the study. The diameter of the foramen of diaphragma sellae varied between specimens. Of 24 specimens, the diaphragma sellae in five (21%) had a tight-type foramen and those in 19 (79%) were more spacious. An increased expression of collagen types I and IV was observed in the pituitary capsule and the diaphragma sellae. In this clinical series, we observed that all types of sellar tumours could expand through the foramen. We observed radiologically and intraoperatively that the diaphragma sellae was displaced laterally and formed a dome in two cases with an adenoma extending to the suprasellar area. Two types of suprasellar extension through the diaphragma sellae are possible: 1) The collagen structure of diaphragma sellae can be destroyed by invasive tumours; 2) The morphology of the foramen of the diaphragma sellae facilitates suprasellar tumoural extension. All sellar tumours, including non-invasive cystic tumours, may invade the suprasellar area by expanding through the foramen of the diaphragma sellae.

Endoscopic Training Model for Intranasal Transsphenoidal Hypophysis Surgery Using a Skull Model and Chicken Wings.

AIM: To evaluate the feasibility of an experimentally designed model for training on endoscopic intranasal transsphenoidal hypophysis surgery. MATERIAL AND METHODS: In this experimental study, a surgical training model for endoscopic transsphenoidal hypophysis surgery was designed to simulate real life surgical challenges, such as drilling through the sella turcica under endoscopic vision. This laboratory experiment was repeated at 1-week intervals and it was observed that surgeons improved their skills. The compatibility of the training model was evaluated as either poor, acceptable or perfect. RESULTS: The results revealed that according to earlier data, greater success occurred in tests conducted after 1 week. Three new specialist neurosurgeons also expressed that their self-confidence increased during the second procedure. CONCLUSION: This laboratory study will result in improved use of microsurgical instruments and understanding of the threedimensional surgical field, as well as the development of manual dexterity. We believe that this model will contribute to the practical training of endoscopic hypophysis surgery.

Measurements and Clinical Application of Anatomical Space for Transfrontal Pituitary Surgery Through Magnetic Resonance Imaging Reconstruction.

OBJECTIVE: This study aims to clarify the relative position of the normal important structures and anatomical spaces formed by the structures passed through during the transfrontal pituitary surgery, and discuss how to avoid some eloquent structures. METHODS: A total of 120 cases of magnetic resonance imaging images from normal adult brains were selected as the object of study and divided into male and female groups. The important adjacent structures of the pituitary passed through during the transfrontal pituitary surgery were marked on the reconstructed images. In all planes of the spaces passing through successively during the pituitary surgery, the morphological parameters such as the size, boundary, structure, and spatial extent of the spaces were measured. RESULTS: The size, boundary, structure, and spatial extent of the space between the 2 optic nerves, the space between the optic nerves and the pituitary stalk, and the space between the tuber cinereum and the interal carotid artery in the plane of the pituitary stalk were measured, the anterior part and the posterior part in male were shorter than those in female (P = 0.021; P = 0.029); no statistically significant difference was found in the measurements of the lengths and angles of these spaces. CONCLUSIONS: The authors' findings provide the surgeons with the detailed anatomical data and help to provide a morphological basis for intraoperative protection of the pituitary and vital adjacent structures and surgical approach.

Effects of GnRH and the dual regulatory actions of GnIH in the pituitary explants and brain slices of Astyanax altiparanae males.

The pituitary gonadotropins, Fsh (follicle-stimulating hormone) and Lh (luteinizing hormone), regulate testicular development and functions in all vertebrates. At the pituitary, different signaling systems regulate the synthesis and secretion of the gonadotropins, such as the hypothalamic neuropeptides GnRH (gonadotropin-releasing hormone) and GnIH (gonadotropin-inhibitory hormone). While GnRH exerts stimulatory roles, the actions of GnIH remain controversial for many teleost species. Therefore, the aim of this study was to evaluate the in vitro effects of chicken GnRH2 (cGnRH2) and zebrafish GnIH-3 (zGnIH-3) on the male gonadotropin and GnRH system expression using pituitary explants and brain slices from a neotropical species with economical and ecological relevance, Astyanax altiparanae. Our results showed that in males, cGnRH2 increased fshb and lhb mRNA levels in the pituitary explants. Interestingly, zGnIH-3 has no effect on basal gonadotropin expression, however zGnIH-3 decreased the cGnRH2-induced fshb and lhb transcripts in male pituitary explants. In the male brain slices, zGnIH-3 showed stimulatory effects, increasing gnrh2 mRNA levels. Overall, our results suggested that GnIH seems to have dual regulatory actions on gonadotropin and GnRH2 expression of A. altiparanae males. This study provided basic information on endocrine regulation of A. altiparanae reproduction, and the obtained results will expand our knowledge, improving the reproductive management of this economically important freshwater species.

Anatomical assessment of the endoscopic endonasal approach for the treatment of paraclinoid aneurysms.

OBJECTIVE: Endoscopic endonasal approaches (EEAs) are increasingly being incorporated into the neurosurgeon's armamentarium for treatment of various pathologies, including paraclinoid aneurysms. However, few anatomical assessments have been performed on the use of EEA for this purpose. The aim of the present study was to provide a comprehensive anatomical assessment of the EEA for the treatment of paraclinoid aneurysms. METHODS: Five cadaveric heads underwent an endonasal transplanum-transtuberculum approach to expose the paraclinoid area. The feasibility of obtaining proximal and distal internal carotid artery (ICA) control as well as the topographic location of the origin of the ophthalmic artery (OphA) relative to dural landmarks were assessed. Limitations of the EEA in exposing the supraclinoid ICA were also recorded to identify favorable paraclinoid ICA aneurysm projections for EEA. RESULTS: The extracavernous paraclival and clinoidal ICAs were favorable segments for establishing proximal control. Clipping the extracavernous ICA risked injury to the trigeminal and abducens nerves, whereas clipping the clinoidal segment put the oculomotor nerve at risk. The OphA origin was found within 4 mm of the medial opticocarotid point on a line connecting the midtubercular recess point to the medial vertex of the lateral opticocarotid recess. An average 7.2-mm length of the supraclinoid ICA could be safely clipped for distal control. Assessments showed that small superiorly or medially projecting aneurysms were favorable candidates for clipping via EEA. CONCLUSIONS: When used for paraclinoid aneurysms, the EEA carries certain risks to adjacent neurovascular structures during proximal control, dural opening, and distal control. While some authors have promoted this approach as feasible, this work demonstrates that it has significant limitations and may only be appropriate in highly selected cases that are not amenable to coiling or clipping. Further clinical experience with this approach helps to delineate its risks and benefits.

Pituitary gland volumes in patients with obsessive-compulsive disorder before and after cognitive-behavioral therapy

Objective: The beneficial effects of psychopharmacological and cognitive behavioral therapy (CBT) on the brain are not well understood. In a previous study, we found smaller pituitary volumes in patients with obsessive-compulsive disorder (OCD). The purpose of this study was to examine the effect of CBT on pituitary gland volume. Methods: A total of 81 patients with various anxiety disorders and the same number of healthy controls underwent magnetic resonance imaging, and their pituitary gland volumes were compared at baseline. Pituitary gland volumes were also measured before and after CBT in the patient group. Results: OCD patients had smaller pituitary gland volumes at baseline than healthy controls (0.54±0.29 cm3 for OCD patients vs. 0.82±0.30 cm3 for healthy controls; p < 0.001). We found no significant changes in OCD patient pituitary gland volume after the 16-week treatment period, with mean pre- and post-treatment values of 0.54±0.29 cm3 and 0.56±0.32 cm3, respectively (p > 0.05). Conclusion: Our results indicate an absence of post-CBT volumetric changes in the pituitary gland of OCD patients.

Morphology and ultrastructure of the hypophysis in bactrian camels ( Camelus bactrianus ) / Morfología y ultraestructura de la hipófisis en camellos bactrianos ( Camelus bactrianus )

The morphology of the hypophysis in Bactrian camel has not been described in the literature, despite it being the master of endocrine organs in vertebrates. In the present study, we examined the morphological features of the hypophysis in Bactrian camel by means of gross anatomy, light and electron microscope. Our findings showed that the gland was a protrusion of the bottom of the hypothalamus at the base of the brain with about 1.54 g in weight and 2 cm3 in volume. The hypophysis consists of two major parts: fully developed adenohypophysis and underdeveloped neurohypophysis, the adenohypophysis consists of pars distalis and pars intermedia. Seven type cells of the pars distalis could be distinguished with immunohistochemical techniques and electron micrographs: somatotroph, mammotroph, thyrotroph, corticotroph, gonadotroph, chromophobe and stellate cells which is in accordance with most mammals. Notably, the stellate cells could be obviously distinguished from chromophobe cells in histological oberservation. Moreover, the corpusculum neurosecretorium (Herring bodies) were rare in the external neurohypophysis, and mainly distributed in the internal neurohypophysis, this was different from most mammals. Results from this study would provide a necessary theoretical basis for ongoing investigations for Bactrian camels and their good adaptability in arid and semi-arid circumstances.

La morfología de la hipófisis en el camello bactriano no ha sido descrita en la literatura, a pesar de ser el maestro de los órganos endocrinos en los vertebrados. En el presente estudio, examinamos las características morfológicas de la hipófisis del camello bactriano por medio de anatomía general, microscocopía de luz y microscopía electrónica. Nuestros hallazgos mostraron que la hipófisis es una protuberancia ubicada en la porción inferior del hipotálamo, en la base del cerebro, con aproximadamente 1,54 g de peso y 2 cm3 de volumen. La hipófisis consta de dos partes principales: adenohipófisis, completamente desarrollada, y neurohipófisis, poco desarrollada; además, la adenohipófisis consta de una pars distalis y una pars intermedia. Con técnicas inmunohistoquímicas y micrografías electrónicas en la pars distalis se pudieron distinguir siete tipos de células: somatotrofas, mamotróficas, tirotrofas, corticotrofas, gonadotrofas, cromófobas y estrelladas, lo que es similar a la mayoría de los mamíferos. En la observación histológica las células estrelladas se pueden distinguir naturalmente de las células cromófobas. Además, es rara la presencia de corpusculum neurosecretorium (Cuerpos de Herring) en la neurohipófisis externa, hallándose distribuidos principalmente en la neurohipófisis interna, esto es diferente a lo encontrado en la mayoría de los mamíferos. Los resultados de este estudio proporcionarían una base teórica necesaria para las investigaciones en curso de los camellos bactrianos y su buena adaptabilidad en circunstancias áridas y semiáridas.

Pituitary size alteration and adverse effects of radiation therapy performed in 9 dogs with pituitary-dependent hypercortisolism.

The purpose of this study was to determine the therapeutic and/or adverse effects of radiation therapy (RT) against pituitary tumors in dogs with pituitary-dependent hypercortisolism, as monitored by frequent post-RT detailed MRI examinations, clinical signs, and changes in hormone concentrations. Nine dogs with an adrenocorticotropic hormone (ACTH)-secreting pituitary mass diagnosed by magnetic resonance imaging (MRI) underwent RT for 4weeks (total of 48Gy in 4-Gy fractions). Pituitary height/brain area (P/B) value, clinical signs, basal plasma ACTH concentrations, serum cortisol concentrations (pre- and post-ACTH stimulation test) and adverse effects of RT were evaluated before and post-RT. The P/B value was significantly lower in all nine dogs post-RT. One dog lacking any neurological signs demonstrated no change in clinical signs pre and post-RT. Out of 8 dogs which exhibited neurological signs pre-RT, half of them demonstrated complete resolution of their signs, whereas the other half showed transient resolution. In all animals with recurrence of neurological signs, pituitary tumor regrowth was not observed; however, MRI revealed moderate to severe pituitary hemorrhage. Late adverse effect (bilateral otitis media) was observed in three of nine dogs post-RT. RT did not induce any significant changes in the dogs' basal plasma ACTH concentration and pre- and post-ACTH serum cortisol concentrations. In conclusion, RT is effective to reduce pituitary size and the mass effect, but does not appear to affect blood hormone concentrations, necessitating additional medical treatment against hypercortisolism. Periodic MRI imaging post-RT enables early detection of adverse effects of RT.

Measurement of the normal feline pituitary gland in brachycephalic and mesocephalic cats.

Objectives The purpose of this study was to determine differences in normal feline pituitary dimensions in brachycephalic and mesocephalic cats as a basis for establishing cryohypophysectomy in cats. Methods Measurements were performed on sagittal T2-weighted and transverse post-gadolinium T1-weighted or T1 3D fast field echo-weighted MRI images. A total of 32 brachycephalic and 27 mesocephalic cats were examined. Inter-observer reproducibility was assessed by t-test and Bland-Altman analysis. Results The cats were 0.6-15.9 years of age with a body weight range of 1.84-6.60 kg. For brachycephalic cats, the mean pituitary gland sagittal height was 2.15 ± 0.15 mm, pituitary gland transverse height was 2.42 ± 0.21 mm, pituitary gland transverse width was 4.44 ± 0.27 mm and pituitary gland sagittal length was 3.14 ± 0.30 mm. In mesocephalic cats, the pituitary gland dimensions were 2.94 ± 0.16 mm, 3.09 ± 0.26 mm, 4.73 ± 0.31 mm and 4.88 ± 0.30 mm for pituitary gland sagittal height, transverse height, transverse width and sagittal length, respectively. There was a highly significant correlation between brachycephalic and mesocephalic cats and pituitary gland height and length ( P <0.0001), respectively. Sex also had an effect on pituitary gland measurements. Neutering status had no significant effect on hypophyseal measurements. Age had a significant influence on pituitary gland height, width and length in the brachycephalic population. Inter-observer reproducibility was good to excellent. Conclusions and relevance The different pituitary measurements in brachycephalic and mesocephalic cats has to be considered if surgery comes into question. There are ranges in pituitary gland sizes, even among the mesocephalic cat population. Thus, exact measuring of the pituitary gland is crucial before any surgical intervention.