Abnormal Pituitary Gland Research Articles

Normal Pituitary Gland Size and Morphology and Its Variations Related To Age and Gender: An MRI Evaluation

Introduction: The pituitary gland is regarded as the master endocrine gland of the body. Subtle alterations in the size can cause significant changes to other endocrine glands and hormonal status. Magnetic Resonance Imaging (MRI) is the investigation of choice to examine pituitary gland. It is important to know the range of normal size and variations according to age and gender to enable radiologists to suggest what might be an abnormal pituitary gland. Aims: This study aims to examine normal size, volume and shape of pituitary gland and to establish a normal reference value for pituitary size in different age groups and genders. Methods: MRI Brain of 137 patients were studied retrospectively and patients with endocrinal abnormalities were excluded from the study. Images were acquired in General Electronics 1.5 Tesla MRI machine and mid-sagittal T1WI and coronal T2WI were selected for accurate measurement of the gland. Height, AP diameter, Transverse diameter, and volume were calculated for each individual and the collected data was categorized based on age and sex for analysis. Pearson’s correlation test was done to establish a relation between age and volume of the gland and a p-value of <0.05 was considered as significant. Results: Our study included 137 patients (57 males, 80 females) with age ranging from 3 to 86 years. The study was divided into six age groups. Mean pituitary height, AP diameter, transverse diameter and volume of the gland were 6mm, 8.9mm, 12.3 mm, and 354.5 mm3 respectively. The gland observed a gradual increase in size up to the third decade and was more pronounced in the female population. A steady decline in the size of the gland was noted after 30 years for both populations. Conclusion: Good understanding of the normal size and shape of pituitary gland and its variation with age and gender is a must for every radiologist to compare with an abnormal increase in size.

SAT-288 Pituitary Developmental Defects Caused by Haploinsufficiency for the Transcription Factor SIX3 Are Worsened by POU1F1 Deficiency

Advances in genomic technologies are revolutionizing the practice of medicine by delivering molecular diagnoses that can be informative for prognosis and treatment of genetic disorders. Most of the known genetic causes of multiple pituitary hormone deficiency have been investigated as monogenic disorders. It can be challenging to predict clinical features from genetic data, as loss of function mutations in some genes can present with a spectrum of phenotypes ranging from craniofacial abnormalities, intellectual disability, and neurosensory and neuroendocrine defects to pituitary hormone deficiency with no other abnormalities. Although maternal exposures could be contributing factors, the contribution of rare, deleterious variation in other genes is a likely contributor. In humans, loss of function mutations in the transcription factor SIX3 cause variable, autosomal dominant holoprosencephaly with incomplete penetrance, and mouse models recapitulate some of the clinical features. Because Six3 and Pou1f1 gene expression patterns overlap in pituitary development, we hypothesized that doubly heterozygous mice (Six3+/-; Pou1f1+/dw) might have pituitary anomalies not present in singly heterozygous mice. We intercrossed Six3+/- and Pou1f1+/dw mice to produce doubly heterozygous animals. At e11.5, both Six3+/- and Six3+/-; Pou1f1+/dw exhibited abnormal morphology of the developing infundibulum and Rathke’s pouch, although ventral diencephalon expression of Tle4, Fgf10, and Nkx2.1 appeared normal. Both newborn Six3+/- and Six3+/-; Pou1f1+/dw littermates had abnormal pituitary gland morphology that resembled that of Aes-/-. AES is a co-repressor that interacts with SIX3. Specification of vasopressin neurons and anterior lobe hormone cell types appeared normal. Mice of all genotypes were born in expected Mendelian ratios (N=144, p=0.49), and there were no significant differences in body weight at 3 wks. A portion of the Six3+/- and doubly heterozygous mice developed hydrocephalus, exhibited failure to thrive, and died (6-9% of N=82, 85, respectively). At 6 wks, 25% (N=61) of the Six3+/-; Pou1f1+/dw animals exhibited striking pituitary dysmorphology in which the rostral aspect of the pituitary penetrated the palate. This was not observed in single heterozygotes. These results reveal that haploinsufficiency for Six3 affects Rathke’s pouch formation, resulting in pituitary gland dysmorphology in and around the stem cell niche. A significant portion of the Six3+/-; Pou1f1+/dw doubly heterozygous mice have a more pronounced pituitary phenotype than Six3+/-, supporting the possibility of digenic pituitary disease and highlighting phenotypic variability. Genetically engineered mice provide an excellent tool for assessing the possibility of gene-gene interactions that could enhance the severity of hypopituitarism and associated craniofacial development.

Diagnosis and Management of pituitary disease with focus on the role of Magnetic Resonance Imaging.

Magnetic resonance (MR) imaging is an essential tool in the diagnosis and management of pituitary diseases, indispensable for making correct treatment decisions. Successful management and follow-up of pituitary pathology requires an understanding of the MR appearance of normal and abnormal structures in the sellar region. This review will describe the MR appearance of the normal and abnormal pituitary gland and proposes an algorithm for the management strategy of some of the most common abnormalities in or around the sella.

Pituitary magnetic resonance imaging abnormalities in young female patients with hypogonadotropic hypogonadism.

ObjectiveTo elucidate the association between clinical and laboratory characteristics and pituitary magnetic resonance imaging (MRI) abnormalities in young female patients with hypogonadotropic hypogonadism (HH).MethodsWe retrospectively investigated a series of 74 female patients (age range, 14–42 years) with normoprolactinemic HH who underwent pituitary MRI. Pubertal milestones and hormonal features of patients with small pituitary glands (PGs) and space-occupying lesions were compared with those of patients with normal PGs.ResultsThe overall frequency of abnormal PGs was 35.1%, with space-occupying lesions observed in 8 patients (10.8%), and small PG observed in 18 patients (24.3%). The mean serum gonadotropin level was not different between patients with and without pituitary MRI abnormalities (P>0.05). Space-occupying lesions were not associated with low gonadotropin levels, type of amenorrhea, or presence of secondary sex characteristics. The frequency of space-occupying lesions was higher in patients with interrupted puberty (25.0%) than in patients who did not go through puberty (4.8%) or had a normal puberty (9.8%), but were not statistically significant (P>0.05). Small PG was associated with low gonadotropin levels and type of amenorrhea (P<0.05).ConclusionClinically significant space-occupying lesions were not associated with low gonadotropin levels, type of amenorrhea, or presence of secondary sex characteristics. However, the frequency of space-occupying lesions was higher in patients with interrupted puberty than in patients who did not go through puberty or who with normal puberty.

T22. PITUITARY GLAND VOLUME DIFFERENCES IN INDIVIDUALS WITH PSYCHOSIS: RESULTS FROM THE BIPOLAR-SCHIZOPHRENIA NETWORK ON INTERMEDIATE PHENOTYPES (B-SNIP) STUDY

BackgroundWhen exposed to stress, the hypothalamic-pituitary-adrenal axis is hyperactivated, which can cause the enlargement of the pituitary gland. Hence, pituitary gland volume could be a biomarker of stress present in psychosis. However, it remains unclear if individuals with psychosis have larger pituitary gland than healthy people. Previous studies investigating this question used small samples and reported inconsistent results. In the current study, we used an automated multi-atlas segmentation method to investigate the differences between pituitary gland volumes in a large sample of individuals on the psychosis spectrum.MethodsData collection was completed across six sites in the Bipolar-Schizophrenia Network on Intermediate Phenotypes (B-SNIP) consortium with a total of 755 participants included in the study - 174 individuals with schizophrenia (SZ), 115 with schizoaffective disorder (SZA), 167 with psychotic bipolar disorder (PBD), and 299 healthy controls (HC). Structural magnetic resonance images were acquired and pituitary gland volumes were obtained using the automated MAGeT-Brain algorithm. General linear model and post-hoc independent t-tests were used to analysis the differences between subgroups of patients using clinical diagnosis and agnostic Biotype classification (Biotype 1 being the most cognitively impaired). We also explored potential effect of antipsychotic intake, symptoms severity and duration of illness. In all analyses, we used Bonferroni correction for multiple comparisons and entered confounds as covariates (age, sex, race, intracranial volume, and site).ResultsOverall, the pituitary gland volumes were not significantly different between patients and HC. No significant main effect of diagnosis was observed, but SZ patients had trending larger pituitary volume compared to HC (p=.033, uncorrected). We observed a significant main effect of Biotype (p=.003), with Biotype 1 having significantly larger pituitary gland than HC and Biotype 2 (p=.004 and p=.013). In the patients group, no significant relationship between the pituitary gland and the amount of antipsychotic intake was observed (r=.02, p=.68). Significant correlations with the pituitary gland volume were observed with symptoms severity (r=.22, p=.000), and with the duration of illness (r=-.18, p=.002). Importantly, Biotypes did not significantly differ in terms of symptoms severity nor duration of illness.DiscussionAs a group, individuals with psychosis do not have abnormal pituitary gland volume, but larger pituitary gland is related to shorter duration of illness and greater symptoms severity. Therefore, larger pituitary gland volume could be a state-related biomarker of psychosis. Moreover, while we did not observe any significant subgroup differences using clinical diagnosis, our results suggest an increase in pituitary volume in biotype 1 patients compared to HC. These findings clarify previous inconsistent reports, and encourage further investigation of stress biomarkers in individual with psychosis with lower cognitive abilities. In the future, this could lead to the development of more targeted treatments for this specific subgroup of patients.

Volumetric evaluation of pituitary gland in dog and cat using computed tomography.

The objective of this study was to evaluate the pituitary gland dimensions due to age and weight using computed tomography (CT) in dogs and cats. The CT images of pituitary gland were assessed in 11 client-owned dogs (six males and five females; age range, 1 to 9 years) and 15 client-owned cats (eight males and seven females; age range, 1 to 14 years) with no evidence of pituitary diseases. The length, height, width and volume of the pituitary gland were measured in sagittal and transverse planes. Mean pituitary length, width, height and volume (± standard deviation: SD) were respectively 4.96 (± 0.69 mm), 3.62 (± 0.64 mm), 2.62 (± 0.05 mm) and 26.19 (± 7.99 mm3) in cats and were 7.00 (± 2.14 mm), 4.80 (± 1.20 mm), 3.80 (± 0.70 mm) and 77.53 (± 51.64 mm3) in dogs, respectively. Mean pituitary height-to-brain ratio (P:B ratio), (± SD) in cats and dogs was 0.28 (± 0.05) and 0.21 (± 0.03), respectively and mean percent of pituitary volume to brain volume (± SD) in cats and dogs was 0.10 (± 0.05) and 0.10 (± 0.07), respectively. There was no significant correlation between the size of pituitary gland and age, weight and body condition score (BCS) in dogs, however in cats, significant difference was found between height of pituitary gland and weight and BCS, pituitary width and weight and P:B ratio and BCS. These findings could be useful to identify abnormal pituitary gland enlargement in CT images. To be more accurate in the assessments, further studies are required.

Accumulation of 11C-methionine in the normal pituitary gland on 11C-methionine PET.

Background For pituitary tumors, positron emission tomography (PET) with 11C-methonine (MET) has been reported as feasible to facilitate diagnosis. MET is well-known to accumulate in the normal pituitary glands, but almost no studies have examined the degree of MET accumulation in the normal pituitary gland. Purpose To investigate accumulation of MET in normal pituitary gland on PET/CT. Material and Methods Among patients who underwent PET/CT using MET over the past 7 years, 77 patients who fulfilled our criteria for normal pituitary glands were retrospectively selected. Maximum standardized uptake value (SUVmax) for the pituitary gland was measured. Results SUVmax of MET in the pituitary gland was in the range of 0.9-6.6 (mean ± standard deviation = 2.60 ± 1.04). A negative correlation between SUVmax and patient age (y = -0.032 × + 4.29, n = 77, r = 0.55) was found by linear regression analysis. SUVmax of the pituitary gland did not differ significantly between women and men. Conclusion MET shows strong accumulation in normal pituitary gland. PET/CT would thus be feasible to differentiate between normal and abnormal pituitary glands.

A familial GLI2 deletion (2q14.2) not associated with the holoprosencephaly syndrome phenotype.

Molecular alterations of the GLI2 gene in 2q14.2 are associated with features from the holoprosencephaly spectrum. However, the phenotype is extremely variable, ranging from unaffected mutation heterozygotes to isolated or combined pituitary hormone deficiency, and to patients with a phenotype that overlaps with holoprosencephaly, including abnormal pituitary gland formation/function, craniofacial dysmorphisms, branchial arch anomalies, and polydactyly. Although many point mutations within the GLI2 gene have been identified, large (sub) microscopic deletions affecting 2q14.2 are rare. We report on a family with a 4.3 Mb deletion in 2q14 affecting GLI2 without any dysmorphologic features belonging to the holoprosencephaly spectrum. This family confirms the incomplete penetrance of genomic disturbances affecting the GLI2 gene. However, the family presented here is unique as none of the three identified individuals with a GLI2 deletion showed any typical signs of holoprosencephaly, whereas all patients reported so far were referred for genetic testing because at least one member exhibited holoprosencephaly and related features.

Évaluation de la prise en charge de patients présentant un déficit en hormone de croissance (GHD) traité dans l’enfance, avant et après la période de la transition

Growth hormone deficiency (GHD) may result from a failure of hypothalamic GHRH production or release, from congenital disorders of pituitary development, or from central nervous system insults including tumors, surgery, trauma, radiation or infiltration from inflammatory diseases. Idiopathic, isolated GHD is the most common sporadic form of hypopituitarism. GHD may also occur in combination with other pituitary hormone deficiencies, and is often referred to as hypopituitarism, combined pituitary hormone deficiency (CPHD), multiple pituitary hormone deficiency (MPHD) or panhypopituitarism. Children without any identifiable cause of their GHD are commonly labeled as having idiopathic hypopituitarism.MRI imaging is the technique of choice in the diagnosis of children with hypopituitarism. Marked differences in MRI pituitary gland morphology suggest different etiologies of GHD and different prognoses. Pituitary stalk agenesis and ectopic posterior pituitary (EPP) are specific markers of permanent GHD, and patients with these MRI findings show a different clinical and endocrine outcome compared to those with normal pituitary anatomy or hypoplastic pituitary alone. Furthermore, the classic triad of ectopic posterior pituitary gland, pituitary stalk hypoplasia/agenesis, and anterior pituitary gland hypoplasia is generally associated with permanent GHD. T2 DRIVE images aid in the identification of pituitary stalk without the use of contrast medium administration. Future developments in imaging techniques will undoubtedly reveal additional insights. Mutations in a number of genes encoding transcription factors – such as HESX1, SOX2, SOX3, LHX3, LHX4, PROP1, POU1F1, PITX, GLI3, GLI2, OTX2, ARNT2, IGSF1, FGF8, FGFR1, PROKR2, PROK2, CHD7, WDR11, NFKB2, PAX6, TCF7L1, IFT72, GPR161 and CDON – have been associated with pituitary dysfunction and abnormal pituitary gland development; the correlation of genetic mutations to endocrine and MRI phenotypes has improved our knowledge of pituitary development and management of patients with hypopituitarism, both in terms of possible genetic counseling, and of early diagnosis of evolving anterior pituitary hormone deficiencies.

A patient with a mild holoprosencephaly spectrum phenotype and heterotaxy and a 1.3 Mb deletion encompassing GLI2

Loss-of-function mutations of GLI2 are associated with features at the mild end of the holoprosencephaly spectrum, including abnormal pituitary gland formation and/or function, and craniofacial abnormalities. In addition patients may have branchial arch anomalies and polydactyly. Large, microscopically visible, interstitial deletions spanning 2q14.2 have been reported in patients with multiple congenital anomalies and intellectual disability. We report here on a patient with a mild holoprosencephaly spectrum phenotype (bilateral cleft lip and palate and abnormal pituitary gland formation with panhypopituitarism) and normal psychomotor development, who was found to carry a 1.3 Mb submicroscopic heterozygous deletion in 2q14.2, encompassing the GLI2 gene. We review the genotype and phenotype of previously published probands with GLI2 aberrations. Our findings confirm the association of haploinsufficiency of GLI2 and mild HPE spectrum features. Consistent with prior reports, we observed incomplete penetrance of the deletion in the family, illustrating the multifactorial etiology of holoprosencephaly spectrum features. In addition to the holoprosencephaly spectrum features, the proband had heterotaxy of the abdominal organs. Mutations in the known heterotaxy genes (NODAL, ZIC3 and CFC1) were excluded. The deletion contains five genes, in addition to GLI2, including the EPB4.1l5 gene. Based on findings in Epb4.1l5 mutant mice we hypothesize that Epb4.1l5 is a candidate gene for the heterotaxy observed in the proband.

Computed tomography and low-field magnetic resonance imaging of the pituitary gland in dogs with pituitary-dependent hyperadrenocorticism: 11 cases (2001–2003)

To compare the results of computed tomography (CT) and magnetic resonance imaging (MRI) of the pituitary gland in dogs with pituitary-dependent hyperadrenocorticism (PDH) caused by histologically confirmed pituitary adenoma. Retrospective case series. 11 dogs with PDH that underwent transsphenoidal hypophysectomy. Medical records of dogs examined between January 2001 and March 2003 were reviewed. Dogs were included in this study if they had clinical signs of hypercortisolism at the time of admission (for which PDH was diagnosed) and underwent transsphenoidal hypophysectomy. Pre- and postcontrast CT and low-field MRI (0.2-Tesla magnet) were performed on the same day as surgery for each dog. An abnormal pituitary gland was found in 7 dogs by use of MRI and in the same 7 dogs by use of CT. Significant differences were found between postcontrast CT and MR images for height, width, and length of the pituitary gland; brain area; and thickness of the sphenoid bone. However, the pituitary gland height-to-brain area ratio determined from postcontrast CT and MR images was not significantly different. The signal-to-noise ratio and contrast-to-noise ratio of pre- and postcontrast MR images were significantly higher than those of the CT images. Low-field MRI and dynamic CT imaging of the pituitary gland provided comparable information on the presence of pituitary adenomas in dogs with PDH.

Relationship between Arginine Vasopressin and High Signal Intensity in the Pituitary Posterior Lobe on T1-Weighted MR Images in Dogs

The posterior lobe of the pituitary gland (PL) normally shows characteristic high signal intensity (SI) on T1-weighted MR images (T1WI) in humans. The high SI is thought to represent storage of arginine vasopressin (AVP) in the PL. Normal dogs also show a high SI on T1WIs, but the origin is unclear. In the present study, we investigated whether the high SI in the PL on T1WIs in normal dogs is caused by AVP. We examined the SI in the PL on T1WIs, plasma AVP concentrations and plasma osmolality in normal dogs after excessive AVP secretion was induced by hypertonic saline overload. In addition, functional changes in the supraoptic nucleus and paraventricular nucleus of the hypothalamus under AVP secretion-stimulated conditions were examined immunohistologically. Under hypertonic saline overload, plasma osmolality and plasma AVP concentrations gradually increased, while the SI of the PL gradually decreased. This suggests that AVP secretion was stimulated by elevated osmolality. Moreover, there was a significant negative correlation between plasma AVP concentrations and the SI ratio of the PL. An immunohistochemical study of the hypothalamus nucleus revealed that AVP-immunopositive cells significantly increased in the hypertonic saline loaded dogs. We concluded that the high SI in the PL in T1WIs in normal dogs was caused by AVP stored at the site, and examination of the SI in the PL using MRI is useful for diagnosis of abnormal pituitary glands.

Dynamic computed tomography of the pituitary gland in dogs with pituitary-dependent hyperadrenocorticism.

Dynamic computed tomography (CT) of the pituitary gland was performed in 55 dogs with pituitary-dependent hyperadrenocorticism (PDH) that underwent transsphenoidal hypophysectomy. On routine contrast-enhanced CT images, microadenomas of the pituitary gland often are indistinguishable from nontumorous pituitary tissue because of isoattenuation. Dynamic CT may allow visualization of these adenomas. The changes in the contrast-enhancement pattern of the pituitary during dynamic CT in 55 dogs with PDH were correlated with surgical and histopathologic findings. In 36 dogs, dynamic CT identified distinct contrast enhancement of the neurohypophysis (pituitary flush). In 24 dogs, this pituitary flush was displaced, which indicated the presence of an adenoma. This observation was confirmed surgically and histopathologically in 18 of the 24 dogs. In 19 dogs, there was a diffusely abnormal contrast-enhancement pattern. CT findings agreed with surgical findings in 13 of these dogs and with histopathologic findings in all 19 dogs. It is concluded that a dynamic series of scans should be included in the CT protocol of the pituitary gland in dogs with PDH because it allows for identification of an adenoma or a diffusely abnormal pituitary gland.

Dynamic Computed Tomography of the Pituitary Gland in Dogs with Pituitary-Dependent Hyperadrenocorticism

Dynamic computed tomography (CT) of the pituitary gland was performed in 55 dogs with pituitary-dependent hyperadrenocorticism (PDH) that underwent transsphenoidal hypophysectomy. On routine contrast-enhanced CT images, microadenomas of the pituitary gland often are indistinguishable from nontumorous pituitary tissue because of isoattenuation. Dynamic CT may allow visualization of these adenomas. The changes in the contrast-enhancement pattern of the pituitary during dynamic CT in 55 dogs with PDH were correlated with surgical and histopathologic findings. In 36 dogs, dynamic CT identified distinct contrast enhancement of the neurohypophysis (pituitary flush). In 24 dogs, this pituitary flush was displaced, which indicated the presence of an adenoma. This observation was confirmed surgically and histopathologically in 18 of the 24 dogs. In 19 dogs, there was a diffusely abnormal contrast-enhancement pattern. CT findings agreed with surgical findings in 13 of these dogs and with histopathologic findings in all 19 dogs. It is concluded that a dynamic series of scans should be included in the CT protocol of the pituitary gland in dogs with PDH because it allows for identification of an adenoma or a diffusely abnormal pituitary gland.

Molecular analysis of LHX3 and PROP-1 in pituitary hormone deficiency patients with posterior pituitary ectopia.

The cause of posterior pituitary ectopia associated with anterior pituitary hormone deficiencies is unknown. We describe children with combined pituitary hormone deficiency (CPHD) or isolated GH deficiency. In all cases, magnetic resonance imaging examination revealed abnormal pituitary gland development featuring ectopic posterior lobe location and frequently hypoplastic anterior lobes. Embryonic development of the pituitary requires the coordinated expression of specific transcription factors. Mutations of the PIT-1 and PROP-1 transcription factors are responsible for CPHD in some patients with normally positioned posterior pituitaries. In mice, the Lhx3 LIM homeodomain transcription factor is required for both structural development and cellular differentiation of the pituitary gland. Thus, we hypothesized that mutations in one or both of the two human LHX3 isoforms are responsible for posterior pituitary ectopia associated with anterior pituitary hypopituitarism. Comprehensive molecular analysis of the LHX3 isoforms was performed to test this hypothesis. No loss of function mutations in the LHX3 gene were detected. In addition, analysis of PROP-1 did not reveal mutations that might cause this phenotype. These studies suggest that the abnormal processes leading to the development of CPHD or GH deficiency associated with posterior pituitary ectopia are not a result of aberrant LHX3 or PROP- 1 function, but may be caused by defects at other gene loci.

Perfusion MRI in normal and abnormal pituitary gland a preliminary study

Perfusion MRI (magnetic resonance imaging) of the pituitary gland was performed in 20 healthy volunteers and 63 patients with various lesions involving the pituitary gland. All patients underwent sequential contrast-enhanced MRI using spoiled gradient recalled sequences with high temporal resolution (7 seconds). Four pituitary areas (pituitary stalk, posterior lobe, postero-superior, and antero-inferior adenohypophysis) were tested with a selected region of interest. Maximal contrast percentual variation was calculated. The timing of enhancement in normal patients matched perfectly with normal pituitary vascularization. Abnormal timing in pathological condition was investigated.

Evolving pituitary hormone deficiency is associated with pituitary vasculopathy: dynamic MR study in children with hypopituitarism, diabetes insipidus, and Langerhans cell histiocytosis.

To assess pituitary vascularization in children with hypopituitarism, central diabetes insipidus (DI), or Langerhans cell histiocytosis. Dynamic MR images were obtained through the pituitary stalk after injection of gadopentetate dimeglumine in 21 patients (11 boys and 10 girls, aged 4-17 years) and 10 age-matched control subjects. Initial enhancement of the posterior pituitary lobe occurred simultaneously with that of the straight sinus in all subjects except four patients with central DI and a thick stalk. Enhancement of the entire anterior pituitary lobe was statistically significantly prolonged (P < .005) in the four patients with delayed initial posterior pituitary lobe enhancement. Fast-framing dynamic MR imaging provides new information on the blood supply of the hypothalamic pituitary area in normal and abnormal pituitary glands. Enhancement times exceeding 20 seconds for the posterior pituitary lobe and 30 seconds for the anterior pituitary lobe may suggest abnormal vascularization in the hypophyseal arteries and portal system.

Normal and abnormal pituitary glands: gadopentetate dimeglumine-enhanced MR imaging.

Dynamic magnetic resonance (MR) imaging with a 1.5-T superconductive unit was used in the evaluation of nine normal pituitary glands and 10 pituitary adenomas, including four microadenomas and six macroadenomas. Seven to 10 images were obtained every 20-30 seconds with use of the spin-echo technique after rapid injection of gadopentetate dimeglumine. The earliest contrast material enhancement of normal structures was seen in the infundibulum and posterior lobe of the pituitary gland at 20 seconds, followed by gradual contrast material enhancement of the anterior lobe of the pituitary gland from the junction of the infundibulum to the peripheral portion of the anterior lobe of the pituitary gland within 80 seconds after gadopentetate dimeglumine injection. The peak enhancement of pituitary adenomas occurred at 60-200 seconds, usually after the most marked enhancement of the normal pituitary gland. Microadenomas are best visualized at earlier phases of gadopentetate dimeglumine-enhanced dynamic imaging, with signal intensity lower than that seen on images of normal pituitary glands.

Hypothalamic dysfunction following whole-brain irradiation.

The authors describe 15 cases with evidence of hypothalamic dysfunction 2 to 9 years following megavoltage whole-brain x-irradiation for primary glial neoplasm. The patients received 4000 to 5000 rads in 180- to 200-rad fractions. Dysfunction occurred in the absence of computerized tomography-delineated radiation necrosis or hypothalamic invasion by tumor, and antedated the onset of dementia. Fourteen patients displayed symptoms reflecting disturbances of personality, libido, thirst, appetite, or sleep. Hyperprolactinemia (with prolactin levels up to 70 ng/ml) was present in all of the nine patients so tested. Of seven patients tested with thyrotropin-releasing hormone, one demonstrated an abnormal pituitary gland response consistent with a hypothalamic disorder. Seven patients developed cognitive abnormalities. Computerized tomography scans performed a median of 4 years after tumor diagnosis revealed no hypothalamic tumor or diminished density of the hypothalamus. Cortical atrophy was present in 50% of cases and third ventricular dilatation in 58%. Hypothalamic dysfunction, heralded by endocrine, behavioral, and cognitive impairment, represents a common, subtle form of radiation damage.

Stereotaxic radiofrequency surgery of the normal and the abnormal pituitary gland.

SURGEONS have continually sought an operative approach to pituitary tumors and to the normal pituitary gland that would be maximally effective, safe and innocuous. We have examined in detail the anatomy of the normal sella turcica and have used this information with some basic engineering technics to improve the endonasal trans-sphenoidal approach to the pituitary gland. This has resulted in a relatively atraumatic stereotaxic radiofrequency procedure associated with minimal morbidity. I shall describe the historical, anatomical and technical considerations that preceded our clinical work and the results obtained in 164 patients who underwent operation for angiopathic diabetic retinopathy, metastatic breast . . .