T1 signal hyperintensity in the sellar region: spectrum of findings

Case report: MRI and CT imaging features of a melanocytic tumour affecting a cervical vertebra in an adult dog, and review of differential diagnosis for T1W-hyperintense lesions

A 7-year-old Lhasa Apso presented with a history of left thoracic limb lameness and neck pain. Magnetic resonance imaging revealed a well-defined, extradural lesion that was hyperintense on T1-weighted (T1W) images and isointense on T2-weighted (T2W) images and T2* images located at the left lamina of the C4 vertebra. Computed tomography showed an isoattenuating and contrast-enhancing mass centered on the left C4 vertebral lamina with associated osteolysis. The mass was surgically debulked, and histopathology revealed a malignant melanocytic tumour. The patient recovered completely and received radiotherapy and three doses of the melanoma vaccine as adjunctive treatment. Eighteen months following treatment, the patient presented with neck pain again, but further investigations were declined at this stage, and the patient was euthanised. To the author's knowledge, this is the first case report describing the imaging characteristics of a cervical extradural melanocytic tumour in a dog. This case illustrates the MRI and CT imaging features and treatment of a canine melanocytic tumour of the cervical vertebrae.

Neuroimaging manifestations of paediatric histiocytoses

Histiocytoses are rare multi-system disorders marked by abnormal histiocyte cell proliferation, affecting children with diverse clinical presentations. Classified into five groups in 2016, including Langerhans-related (L), cutaneous (C), malignant (M), Rosai-Dorfman disease (R) and haemophagocytic lymphohistiocytosis (H), newer entities such as ALK-positive histiocytosis have also emerged, heralding the era of molecular (sub)classification. Common entities include Langerhans cell histiocytosis (LCH), Erdheim-Chester disease (ECD), Rosai-Dorfman disease (RDD) and haemophagocytic lymphohistiocytosis (HLH). This pictorial essay aids radiologists in recognising and differentiating paediatric histiocytoses based on unique neuroimaging features.

Analysis of perceptual errors in skull-base pathology

PURPOSE

Medical errors result in significant mortality and morbidity. The purpose of this study is to analyze skull-base errors at a single tertiary institution, identify common anatomic sites of errors, and offer strategies to reduce errors in this region.

METHODS

A Neuroradiology Quality Assurance Database of radiologic errors was searched for attending physician computer tomography and magnetic resonance imaging errors in skull-base pathology from 2014 to 2020. Data were limited to CT and MRI reports. Errors were separated into four subcategories (tumor, trauma, vascular, and congenital) and further divided by relevant anatomic site.

RESULTS

A total of 90 skull-based errors were identified. Most errors were perceptual (87%), with common study types including MRI Brain (39%) and CT Head (24%). Most common errors were tumors (55%), followed by trauma (24%), vascular (10%), and congenital (7%). Six anatomic sites were identified and encompassed over half of errors (58%): sella, occipital bone, cerebellopontine angle/internal auditory canal (CPA/IAC), foramen magnum and clivus, cavernous sinus, and dural venous sinus.

SUMMARY

Most of the skull-base errors were perceptual. Placing a strong emphasis on both the pathology and closely examining its critical anatomic site (sella, occipital bone, CPA/IAC, foramen magnum and clivus, cavernous sinus, and dural venous sinus) could potentially reduce up to 60% of errors in these regions.

M, Prakash TV, Yadav B, Sudarsanam TD. Absence of posterior pituitary bright spot in adults with CNS tuberculosis: A case-control study

INTRODUCTION

Current diagnostic methods used in Central Nervous System Tuberculosis (CNS TB) are limited by the paucibacillary nature of this form of tuberculosis. Posterior pituitary bright spot (PPBS) refers to an area of T1 hyperintensity in the posterior pituitary in MR imaging of the brain. It is found in 80-90% of healthy children and adults. In children with CNS TB, nearly half have absence of PPBS. This finding has not been described in adults. Our study looked for absence of PPBS in MR imaging and its association with CNS tuberculosis.

OBJECTIVE

To study prevalence of the absence of PPBS in patients with CNS tuberculosis when compared to a control group of normal patients.

METHODS

This was a retrospective case-control study of 100 patients with CNS tuberculosis and 200 controls (matched in 1:2 ratio) of patients with normal MRI brain. The MRI images were presented to a blinded radiologist in a randomised sequence to report for absence of PPBS. The data was subsequently analysed to look for association of absence of PPBS with CNS tuberculosis.

RESULTS

Absence of PPBS (cases (47%), controls (8.5%)) was significantly associated with CNS tuberculosis in (Odds ratio-7.90, 95%CI 4.04-15.44, P-value<0.0001). The specificity, sensitivity, positive predictive value and positive likelihood ratio are 91.5%, 47%, 73.4% and 5.53 respectively. Adding of absence of PPBS as an additional radiological feature in diagnosis of CNS TB increased the sensitivity from 77% to 84%.

CONCLUSION

Absence of PPBS is significantly associated with CNS tuberculosis and could be a relatively simple diagnostic aid in the diagnosis of CNS tuberculosis.

Recurrent liponeurocytoma: A case report and systematic review of the literature

Background:

Liponeurocytomas are rare neurocytic neoplasms that most often arise in the posterior fossa and affect individuals in the third and fifth decades of life. Most reported cases of this unique tumor in the literature have described a favorable clinical prognosis without recurrence. However, increasing reports of recurrent cases prompted the World Health Organization, in 2016, to recategorize the tumor from Grade I to the less favorable Grade II classification. We conducted a systematic review to identify recurrent cases of this unique tumor and to summarize differences between the primary and recurrent cases of liponeurocytoma.

Methods:

A systematic review exploring recurrent liponeurocytoma cases was conducted by searching the PubMed, Google Scholar, and Scopus databases for articles in English. Abstracts from articles were read and selected for full-text review according to a priori criteria. Relevant full-text articles were analyzed for symptoms, imaging, location, histological, pathological, treatment, and recurrence-free time between the primary and recurrent cases.

Results:

Of 4392 articles, 15 articles accounting for 18 patients were included (level of evidence: IV) in the study. Recurrence-free time decreased from an average of 82 months between the primary tumor resection to first recurrence to 31.3 months between the first and second recurrence. Recurrent tumors demonstrated increased pleomorphic neural cells, necrosis, vascular proliferation, and MIB-1 index when compared to the primary tumor. Several cases also demonstrated decreased lipidizing components when compared to the primary tumor, further indicating increased dedifferentiation. The primary treatment for this tumor was surgical resection with occasional adjunctive radiotherapy.

Conclusion:

Recurrent cases of liponeurocytoma have features of increased malignant proliferation compared to the primary cases. The standard treatment for these primary and recurrent tumors is gross total resection. The role of adjunctive radiotherapy remains a matter of debate.

Imaging response assessment for CNS germ cell tumours: consensus recommendations from the European Society for Paediatric Oncology Brain Tumour Group and North American Children's Oncology Group

Homogeneous and common objective disease assessments and standardised response criteria are important for better international clinical trials for CNS germ cell tumours. Currently, European protocols differ from those of North America (the USA and Canada) in terms of criteria to assess radiological disease response. An international working group of the European Society for Paediatric Oncology Brain Tumour Group and North American Children's Oncology Group was therefore established to review existing literature and current practices, identify major challenges regarding imaging assessment, and develop consensus recommendations for imaging response assessment for patients with CNS germ cell tumours. New clinical imaging standards were defined for the most common sites of CNS germ cell tumour and for the definition of locoregional extension. These new standards will allow the evaluation of response to therapy in patients with CNS germ cell tumours to be more consistent, and facilitate direct comparison of treatment outcomes across international studies.

Magnetic resonance imaging of the normal equine pituitary gland

Magnetic resonance imaging is increasingly available for evaluation of horses with suspected pituitary adenomas; however, published studies describing the MRI features of normal equine pituitary glands are currently lacking. This retrospective, descriptive, anatomic study describes the MRI appearance and size of presumed normal equine pituitary glands and assesses potential correlations between pituitary size, brain size, and patient weight. These findings serve as a reference for MRI evaluation of the equine pituitary gland. Inclusion criteria consisted of adult horses (2-15 years old), over 300 kg with no evidence of Pituitary pars intermedia dysfunction (PPID) and no pituitary abnormalities identified with MRI, yielding 27 horses. Histology was available on seven pituitary glands; all were considered normal by a board-certified anatomic pathologist. Imaging features of the glands were evaluated on T2-weighted and pre- and postcontrast T1-weighted images. Pituitary length, width, and height and brain height and width were measured by two authors on transverse and mid-sagittal plane postcontrast T1 weighted images. The mean ± SD pituitary gland width was 21.0 ± 2.4 mm, height: 10.4 ± 1.9 mm, and length: 24.5 ± 2.7 mm. There were no significant correlations using a Pearson's correlation coefficient between pituitary and brain measurements, pituitary measurement, and body weight, or between brain measurements and body weight. A statistical difference was not identified using an unpaired t-test (p > 0.05) in pituitary and brain measurements between necropsied and non-necropsied horses. Relative to the cerebral white matter, all pituitary glands were isointense to slightly hyperintense on T1-weighted images and isointense on T2-weighted images, with the exception of a focal T1-weighted hyperintensity that was present in the caudal aspect of the pituitary gland in 88% of horses. All pituitary glands were homogenously contrast enhancing. Pituitary dimensions did not correlate with either brain size or body weight in horses.

Hypothalamic Lipoma: Outcome of an Intracranial Developmental Lesion

Background

Hypothalamic lipomas are benign developmental lesions that tend to be discovered incidentally. This article describes the radiological features, outcome, and the postulated theories behind hypothalamic lipomas development.

Methods

The electronic archive of neurosurgery was retrospectively reviewed. All patients with a neuroradiological diagnosis of hypothalamic lipoma, between 2005 and 2020, were included.

Results

Out of 246 patients with intracranial lipomas, a total of six patients with hypothalamic lipomas have been identified. On computed tomography images, one of the hypothalamic lipomas demonstrated calcification. On magnetic resonance imaging, peripheral enhancement after contrast administration was noted in one of the lesions. Considering the benign nature of the lesions, neurosurgical intervention was not indicated.

Conclusion

The majority of patients with hypothalamic lipomas are asymptomatic and undergo brain imaging for other indications. Although uncommon, such developmental lesions can be identified in the general population, especially with the advancement of neuroimaging techniques.

The clinical course of Rathke's cleft cysts in pediatric patients: impact on growth and pubertal development

Rathke's cleft cysts (RCCs) are non-neoplastic epithelial lesions in the sellar or suprasellar regions. RCCs are usually asymptomatic; however, some patients experience headaches, visual disturbances, and endocrine disorders. The best treatment for associated endocrinopathy remains elusive. We aimed to investigate the clinical course, magnetic resonance imaging findings, and response to therapy in 10 pediatric patients with RCCs and endocrinopathy. Growth impairment and precocious puberty were observed to be prevalent. One patient with suprasellar extension of RCC underwent surgery, while the others were treated medically. Of the nine patients, seven patients showed stable cyst size, while two patients displayed reduction in cyst size. Hormone replacement and gonadotropin suppression therapy were found to be effective. Imaging and endocrine follow-ups are warranted because of the potential for changes in the cyst size and hormonal changes.

MR-Based Radiomics for Differential Diagnosis between Cystic Pituitary Adenoma and Rathke Cleft Cyst

Background

It is often tricky to differentiate cystic pituitary adenoma from Rathke cleft cyst with visual inspection because of similar MRI presentations between them. We aimed to design an MR-based radiomics model for improving differential diagnosis between them.

Methods

Conventional diagnostic MRI data (T1-,T2-, and postcontrast T1-weighted MR images) were obtained from 215 pathologically confirmed patients (105 cases with cystic pituitary adenoma and the other 110 cases with Rathke cleft cyst) and were divided into training (n = 172) and test sets (n = 43). MRI radiomics features were extracted from the imaging data, and semantic imaging features (n = 15) were visually estimated by two radiologists. Four classifiers were used to construct radiomics models through 5-fold crossvalidation after feature selection with least absolute shrinkage and selection operator. An integrated model by combining radiomics and semantic features was further constructed. The diagnostic performance was validated in the test set. Receiver operating characteristic curve was used to evaluate and compare the performance of the models at the background of diagnostic performance by radiologist.

Results

In test set, the combined radiomics and semantic model using ANN classifier obtained the best classification performance with an AUC of 0.848 (95% CI: 0.750-0.946), accuracy of 76.7% (95% CI: 64.1-89.4%), sensitivity of 73.9% (95% CI: 56.0-91.9%), and specificity of 80.0% (95% CI: 62.5-97.5%) and performed better than multiparametric model (AUC = 0.792, 95% CI: 0.674-0.910) or semantic model (AUC = 0.823, 95% CI: 0.705-0.941). The two radiologists had an accuracy of 69.8% and 74.4%, respectively, sensitivity of 69.6% and 73.9%, and specificity of 70.0% and 75.0%.

Conclusions

The MR-based radiomics model had technical feasibility and good diagnostic performance in the differential diagnosis between cystic pituitary adenoma and Rathke cleft cyst.

A clinical approach to parasellar lesions in the transition age

Many reviews have summarised the pathology and management of the parasellar region in adult patients, although an analysis of these aspects in the transition years, from puberty onset to the age of peak bone mass, has been lacking. A comprehensive search of English-language original articles, published from 2000 to 2020, was conducted in the MEDLINE database (December 2019 to March 2020). We selected all studies regarding epidemiology, diagnosis and management of the following parasellar lesions: germinoma, craniopharyngioma, Langerhans cell histiocytosis, optic glioma, hypothalamic hamartoma, tuber cinereum hamartoma, cranial chordoma, Rathke cleft cyst, hypophysitis and hypothalamitis during the transition age from childhood to adulthood. In the present review, we provide an overview of the principal parasellar lesions occurring in the transition age. Symptoms are usually a result of the mass effect of the lesions on nearby structures, as well as anterior pituitary deficits. Diabetes insipidus occurs frequently in these patients. In this age group, pubertal developmental disorders may be more evident compared to other stages of life. Parasellar lesions in the transition age mostly include neoplastic lesions such as germinomas, hamartomas, optic gliomas, craniopharyngiomas Langerhans cell histiocytosis and chordomas, and rarely inflammatory lesions (hypophysitis, hypothalamitis). There are limited data on the management of parasellar lesions in the transition age. Endocrine evaluation is crucial for identifying conditions that require hormonal treatment so that they can be treated early to improve the quality of life of the individual patient in this complex age range. The clinical approach to parasellar lesions involves a multidisciplinary effort.

Apoplexy in sporadic pituitary adenomas: a single referral center experience and AIP mutation analysis

Objective

To analyze the clinical, laboratory, and radiological findings and management of patients with clinical pituitary apoplexy and to screen for aryl hydrocarbon receptor-interacting protein (AIP) mutations.

Methods

The clinical findings were collected from the medical records of consecutive sporadic pituitary adenoma patients with clinical apoplexy. Possible precipitating factors, laboratory data, magnetic resonance imaging (MRI) findings and treatment were also analyzed. Peripheral blood samples were obtained for DNA extraction from leukocytes, and the entire AIP coding region was sequenced.

Results

Thirty-five patients with pituitary adenoma were included, and 23 (67%) had non-functioning pituitary adenomas. Headache was observed in 31 (89%) patients. No clear precipitating factor was identified. Hypopituitarism was observed in 14 (40%) patients. MRI from 20 patients was analyzed, and 10 (50%) maintained a hyperintense signal in MRI performed more than three weeks after pituitary apoplexy (PA). Surgery was performed in ten (28%) patients, and 25 (72%) were treated conservatively with good outcomes. No AIP mutation was found in this cohort.

Conclusion

Patients with stable neuroophthalmological impairments can be treated conservatively if no significant visual loss is present. Our radiological findings suggest that hematoma absorption lasts more than that observed in other parts of the brain. Additionally, our study suggests no benefits of AIP mutation screening in sporadic patients with apoplexy.

Pituitary hemorrhage in pituitary adenomas treated with gamma knife radiosurgery: incidence, risk factors and prognosis

Objective: The aims of this study were to investigate the incidence, risk factors and prognosis of pituitary hemorrhage in pituitary adenomas treated with gamma knife radiosurgery (GKRS). Methods and materials: Between December 1993 and December 2016, 751 consecutive pituitary adenoma patients treated with GKRS were retrospectively reviewed in a single center. There were 271 male (36.1%) and 480 female (63.9%) patients with a median age of 38.5 (range, 7.2-84.0) years. The number of nonfunctioning pituitary adenomas (NFPAs) and functioning pituitary adenomas were 369 (49.1%) and 382 (50.9%) respectively. The median follow-up time was 61.1 (range, 12.1-304.4) months. Results: In this study, 88 patients (11.7%) were diagnosed with pituitary hemorrhage before GKRS, 55 patients (7.3%) developed new or worsened pituitary hemorrhage after GKRS (excluding 3 patients with new or worsened pituitary hemorrhage due to tumor regrowth). The median time to new or worsened pituitary hemorrhage after GKRS was 18.9 (range 3.1-70.7) months. Overall, 128 patients (17.0%) were diagnosed with pituitary hemorrhage in the entire series. After adjustment with logistic regression, nonfunctioning pituitary adenomas (NFPAs) (odds ratio [OR]=2.121, 95% confidence interval [CI]=1.195-3.763, p=0.010) and suprasellar extension (OR=2.470, 95% CI=1.361-4.482, p=0.003) were associated with pituitary hemorrhage before GKRS. NFPA (OR=3.271, 95% CI=1.278-8.373, p=0.013) was associated with new or worsened pituitary hemorrhage after GKRS. Five patients received surgical resection for new or worsened pituitary hemorrhage were considered as GKRS treatment failure. Two patients with new hypopituitarism were considered to be owed to new or worsened pituitary hemorrhage after GKRS. Conclusions: New or worsened pituitary hemorrhage after GKRS was not an uncommon phenomenon. NFPA was an independent risk factor of new or worsened pituitary hemorrhage after GKRS. New or worsened pituitary hemorrhage after GKRS could lead to GKRS treatment failure. GKRS might be a precipitating factor of pituitary hemorrhage.

Longitudinal Assessment of Neuroradiologic Features in Wolfram Syndrome

BACKGROUND AND PURPOSE

Wolfram syndrome is a rare genetic disease with characteristic brain involvement. We reviewed the brain MR images of patients with Wolfram syndrome to determine the frequency and characteristics of common neuroradiologic findings.

MATERIALS AND METHODS

We retrospectively reviewed the imaging data of patients with genetically-confirmed Wolfram syndrome who had been recruited to the Washington University Wolfram Syndrome Research Clinic. These patients were evaluated between 2010 and 2019 with annual MRIs, along with other measures. MR images were assessed for clinical neuroradiologic signs at each individual's first and last follow-up visits to characterize the frequency, rate of progression, and clinical correlations of these signs.

RESULTS

We included 30 patients (13 males/17 females; average age at first visit, 14 years; average age at last visit, 19 years). The median duration of follow-up was 5 years (range, 2-9 years). The most common findings were an absent or diminished posterior pituitary bright spot (first, 53%; last, 70%), T1/T2 pons signal abnormalities (first, 53%; last, 67%), optic nerve atrophy (first, 30%; last, 80%), white matter T2 hyperintensities (first, 27%; last, 35%), and cerebellar atrophy (first, 23%; last, 70%).

CONCLUSIONS

Patients with Wolfram syndrome present characteristic neuroradiologic findings that involve the posterior pituitary gland, optic nerves, white matter, brain stem, and cerebellum. These abnormal findings appear at an early age and tend to increase in frequency with time. However, the neurologic significance and neuropathologic mechanisms of each sign require more investigation. Neuroradiologists should be aware of the pattern of these features in Wolfram syndrome.

Associations between early life stress and anterior pituitary gland volume development - A novel index of long-term hypothalamic-pituitary-adrenal axis functioning

Previous research has established associations between early life stress (ELS) and altered pituitary gland volume (PGV) growth during adolescence. The pituitary gland, however, is composed of an anterior and a posterior lobe with distinct histological and neuroendocrinological properties. While the anterior (but not posterior) pituitary gland is directly involved in the hypothalamic-pituitary-adrenal axis (HPAA) stress response, no studies have examined the effects of ELS on anterior PGV (aPGV). The present study investigated whether previously reported associations between ELS and PGV development during adolescence were driven by aPGV versus posterior PGV (pPGV). Ninety-one adolescents (49 males) were included from a longitudinal, community-based adolescent development study investigating risk for psychopathology. ELS (maternal affective behavior, childhood maltreatment, stressful life events) was assessed during early adolescence. Participants underwent two waves of structural magnetic resonance imaging during mid- and late-adolescence, and aPGV and pPGV were manually traced. Regression analyses showed that childhood maltreatment predicted greater aPGV growth in females. This finding was stronger than that previously reported for PGV. No associations were found between ELS and pPGV development. Neither aPGV nor pPGV changes mediated associations between ELS and psychopathology. Results suggest that ELS may accelerate aPGV (but not pPGV) growth throughout adolescence. Investigating the development of aPGV, rather than PGV, represents a novel approach to studying the effects of stress on HPAA functioning.

Pituitary sellar spine in a pediatric patient with diabetes insipidus

A sellar spine is a midline bony spur arising from the ventral aspect of the dorsum sellae. Representing a remnant of the anterior notochord, it is often an incidental finding and thought to be of no clinical significance. However, it has recently been suggested that a potential association may exist between sellar spine and pediatric pituitary endocrinopathies, possibly caused by deformation of the developing pituitary gland by the sellar spine. To our knowledge, this is the first case report demonstrating an association between sellar spine and clinical diabetes insipidus.

High prevalence of adrenal insufficiency at diagnosis and headache recovery in surgically resected Rathke's cleft cysts-a large retrospective single center study

BACKGROUND

Rathke's cleft cysts (RCC) are lesions that arise from Rathke's pouch. Though frequently incidental, resulting symptoms in a minority of cases are indicators for surgical resection, which may prove beneficial.

OBJECTIVE

To characterize a cohort of surgically-resected RCC cases at Oregon Health & Science University; tabulate associated hormonal imbalances and symptoms, possible symptom reversal with surgery, determine recurrence risk; identify predictors of recurrence and headache improvement.

METHOD

Electronic records of all RCC resected cases (from 2006-2016; 11 years) were retrospectively reviewed. Patients had been evaluated by one neuroendocrinologist using a uniform protocol.

RESULTS

A pathological RCC diagnosis was established in 73 of 814 (9%) surgical pituitary cases. The RCC cohort was 77% (n = 56/73) female, mean age was 39.5 ± 14.9 years at first surgery, and at presentation headache was reported in 88% and visual defects/diplopia in 18% of patients. Initial RCC maximum diameter was 1.3 ± 0.7 cm. The most frequent hormonal deficit was cortisol; 24% of patients had a new adrenal insufficiency (AI) diagnosis, however, 36% also had AI at 3 months post-operatively. Mean follow up was 4.0 ± 4.5 years. Two-thirds of patients (41/62) had headache improvement 3 months post-operatively. Post-operative imaging revealed no residual cyst in 58% (38/65). In those patients with no residual RCC, 29% had recurrence and 71% had long lasting cure. From the 42% (27/65) of patients with residual cyst on post-operative imaging; 59% (16/27) remained stable, 26% (7/27) progressed and 15% (4/27) regressed.

CONCLUSION

Symptomatic RCC present mostly in women, with a high proportion reporting headaches. Prevalence of AI at diagnosis is high. Surgery may not achieve adrenal axis recovery, but renders a high percentage of headache improvement. Approximately 25% of RCC will recur by 4 years postoperatively. Clinicians should cautiously screen patients with symptomatic RCC, regardless of lesion size for AI.

Spontaneously infarcted parotid tumours: MRI findings

OBJECTIVES

To report MRI findings of spontaneous infarction in parotid tumours.

METHODS

14 patients (13 male, 1 female; mean age 73 years) with spontaneously infarcted parotid tumours were reviewed retrospectively. MR images were assessed for the location, the presence of synchronous parotid masses, margin characteristics, signal intensity on T ₁ and T ₂ weighted images, and internal architecture according to the distribution of T ₂ signal hyperintensity.

RESULTS

12 tumours were located in the parotid tail and 2 in the superficial lobe. Synchronous parotid masses were seen in four tumours, three of which were located in the ipsilateral parotid tail and one in the contralateral parotid tail. Seven tumours had well-defined margins and seven had ill-defined margins. The signal intensities on T ₁ weighted images were a mixture of high and intermediate in all cases; in 11 tumours, hyperintense areas were dominant. On T ₂ weighted images, all tumours also showed a mixture of high and intermediate signal intensities. Internal architectures on T ₂ weighted images were mosaic hyperintensity in three tumours, central hyperintensity in five, and multiseparated hyperintensity in six.

CONCLUSIONS

Spontaneously infarcted parotid tumours were mostly located in the parotid tail and showed mixed signal intensities with predominant hyperintensity on T ₁ weighted images. Half of the tumours had ill-defined margins, and the internal architectures varied.

Calcified Prolactinoma of the Pituitary Gland: Illustrative Case Reports Highlighting Medical versus Surgical Intervention

The presence of calcification is uncommon in pituitary adenomas, and often lends support to other diagnoses including craniopharyngioma. The majority of calcified pituitary adenomas are prolactin-secreting tumors. We report two patients with calcified macroprolactinomas, one that was treated medically with a biochemical response and partial tumor response, and one that was treated successfully via an endoscopic endonasal transsphenoidal approach. Suspected calcified prolactinomas can be initially managed medically as per standard treatment for typical prolactinomas; however, the presence of diffuse calcification may hinder tumor shrinkage. Tumors that are refractory to medical treatment can be safely managed with surgery.

Presence of the posterior pituitary bright spot sign on MRI in the general population: a comparison between 1.5 and 3T MRI and between 2D-T1 spin-echo- and 3D-T1 gradient-echo sequences

PURPOSE

To describe the prevalence of the posterior pituitary bright spot (PPBS) in the general population on 1.5 and 3T MRI examinations and on 2D-T1 spin-echo (SE) and 3D-T1 gradient-echo (GE) sequences.

MATERIALS AND METHODS

1017 subjects who received an MRI of the brain for aspecific neurological complaints were included. MRI was performed on 1.5T in 64.5% and on 3T in 35.5% of subjects. Presence of the PPBS was evaluated on sagittal 2D T1-SE echo images with slice thickness 3 mm in 67.5% and on sagittal 3D T1-GE with slice thickness 0.9 mm in 32.5% of subjects.

RESULTS

The PPBS was detectable in 95.9% of subjects. After correction for sex and age, no statistically significant difference could be seen concerning PPBS detection between 1.5 and 3T MRI examinations (p = 0.533), nor between 2D T1-SE and 3D T1-GE sequences (p = 0.217). There was a statistically significant association between increasing age and the absence of the PPBS (p < 0.001). The PPBS could not be identified in 6.2% of male subjects, compared to 2.2% of female subjects (p = 0.01).

DISCUSSION

Absence of the PPBS can be seen in 4.1% of patients undergoing MRI of the brain for non-endocrinological reasons. Neither field-strength nor the use of a thick-sliced 2D T1-SE versus a thin-sliced 3D T1-GE sequence influenced the detectability of the PPBS. There is a statistically significant association between increasing age and male sex and the absence of the PPBS.

Primary extracranial nasopharyngeal meningioma in a dog

An 8-year-old Labrador Retriever was presented for inspiratory efforts with stertor. A rhinoscopy and a magnetic resonance imaging scan were performed and revealed a naso-pharyngeal mass. The mass was identified in the nasopharynx without meningeal extension. This mass was both T1- and T2-hyperintense, compared to normal brain parenchyma without significant postcontrast enhancement. The mass was surgically removed and the histologic diagnosis was a mesenchymal tumor. Immunohistochemistry with antibodies was conducted and consistent with an extracranial meningioma. To the authors' knowledge, this is the first case report documenting a primary extracranial nasopharyngeal meningioma in a dog.

Apoplexy in nonfunctioning pituitary adenomas

Pituitary apoplexy is an uncommon event, occurring due to the infarction and/or haemorrhage usually of a previously unknown pituitary adenoma. It can occur in all adenoma subtypes but is more common in nonfunctioning pituitary adenomas. The physiopathology is not completely clear, and precipitating factors, such as major surgeries, anticoagulant use or pituitary dynamic tests, can be found in up to 40% of patients. The clinical presentation is characterized by a rapid onset with a headache as the main symptom, but visual disturbances can also be present as well as meningism and intracranial hypertension. The diagnosis is based on imaging evaluations, mainly using magnetic resonance imaging, which can show various patterns depending on the timeframe following the occurrence of the apoplectic event. Pituitary hormonal deficits are also common, and the evaluation of hormonal levels is mandatory. Pituitary apoplexy can be managed by surgery or conservative treatment, and a multidisciplinary team is essential for the decision-making process. The outcome is usually positive with both surgical and conservative approaches, but surveillance is needed due to the risk of re-bleeding or tumour recurrence.

Magnetic resonance imaging of sellar and juxtasellar abnormalities: atypical findings of common diseases and typical findings of rare diseases

The sellar/juxtasellar region comprises the bone component of the sella turcica, pituitary gland, cavernous sinus, and suprasellar cistern. Abnormalities in this region can be attributed to underproduction or overproduction of hormones or to the neurological signs and symptoms resulting from the compression of adjacent structures. Magnetic resonance imaging (MRI) is currently the imaging method of choice, having supplanted computed tomography. The aim of this study was to demonstrate the common and uncommon imaging aspects of sellar and juxtasellar changes, which could facilitate the differential diagnosis. We retrospectively evaluated the MRI scans of 70 patients with sellar/juxtasellar abnormalities from didactic files, and report those with more unusual changes, where MRI played an important role in diagnosis. All cases were confirmed histologically or clinical laboratory.

Clinical and imaging features of pituitary apoplexy and role of imaging in differentiation of clinical mimics

To discuss the clinical syndrome, review common imaging findings of pituitary apoplexy (PA) and role of imaging in therapy and follow-up. Also, to review other acute clinical scenarios with similar clinical and/or imaging findings as PA. PA is a severe and potentially life-threatening medical emergency, characterized by constellation of symptoms/signs that occur as a result of acute hemorrhage and/or infarction in pituitary gland. Patients present with acute and sudden onset of symptoms/signs, most commonly with severe headache, vision deficits/ophthalmoplegia, altered mental status, and possible pan hypopituitarism. Pre-existing macro adenoma (65-90%), especially non-functioning and prolactinomas, are most susceptible to apoplexy, which undergoes hemorrhage or infarct, but PA can occur with normal pituitary or microadenoma. Because of the probable grave prognosis of PA, imaging characteristics of PA and other acute clinical scenarios with similar clinical and/or imaging findings should be familiar to radiologists. PA is potentially a life-threatening clinical syndrome, however, imaging and clinical findings can lead the radiologist towards appropriate diagnosis, and rule out other clinical mimics. When hemorrhage is secondary to an underlying lesion, regrowth of the pituitary tumor years after a PA episode is possible and patients require long-term clinical and imaging surveillance.

Central Diabetes Insipidus Linked to Rathke's Cleft Cyst, Polyuria in a 17-year-old Girl

A 17-year-old girl presented with polyuria (7 L/day) and polydipsia for one year. Initial urine osmolality was 113mOsm/kg H₂O. Following 6 h of fluid restriction, serum plasma osmolality reached 300mOsm/kg H₂O, whereas urine osmolality was 108mOsm/kg H₂O. Urine osmolality was increased by 427% from 108 to 557mOsm/kg after vasopressin challenge. The patient was diagnosed with central diabetes insipidus, possibly derived from the atypical occupation of a Rathke's cleft cyst at the pituitary stalk following magnetic resonance imaging with enhancement. She was discharged with desmopressin nasal spray (10 µg); urine output was maintained at 2-3 L/day, and urine osmolality was >300 mOsm/kg. Additional pituitary image studies and evaluation of hypopituitarism should be included in the differential diagnosis of patients with central diabetes insipidus.

Clinical manifestations of Rathke's cleft cysts and their natural progression during 2 years in children and adolescents

PURPOSE

Rathke's cleft cyst (RCC) is an asymptomatic benign lesion. With increased interest in pediatric endocrinology, the prevalence of RCCs in children is also increasing. However, the clinical relevance and proper management of RCC is not well defined in children. Therefore, we investigated the clinical manifestations and radiologic features of RCC in children and adolescents, as well as the natural progression of RCC.

METHODS

We retrospectively reviewed the medical records of 91 children and adolescents with RCC diagnosed with magnetic resonance imaging (MRI) in Severance Children's Hospital from January 2006 to December 2015. The clinical, hormonal, and imaging findings were analyzed in patient groups classified according to age. The size of each cyst was assessed in sixty patients who underwent follow-up MRI during the 2 years.

RESULTS

Female patients were predominant (64 vs. 27). The common clinical features at presentation were endocrine dysfunction (59.3%), headache (23.0%), and dizziness (4.4%). Symptoms related to endocrine disorders were more frequent in younger patients. In 7 patients managed surgically, the cysts were significantly larger and more frequently located in the suprasellar region. Of 60 nonsurgical patients with a follow-up MRI performed within 2 years after the diagnosis, the RCC size increased in about 26.7% (n=16).

CONCLUSIONS

Although 94.4% of the patients with RCC had clinical symptoms, surgery was performed in only about 7.5% of patients. RCC is associated with pituitary insufficiency, thus, baseline and follow-up endocrine function tests are required. Additionally, regular MRI follow-up is required in long-term period to monitor change in size.

Fluid-fluid level on magnetic resonance images may predict the occurrence of pituitary adenomas in cystic sellar-suprasellar masses

The aim of the present study was to evaluate the value of identifying fluid-fluid level via preoperative magnetic resonance (MR) images in differentiating pituitary adenomas from craniopharyngioma, Rathke's cleft cyst (RCC), and other cystic sellar-suprasellar lesions. The data of 293 consecutive patients who underwent surgery for sellar-suprasellar lesions between July 2010 and December 2012 was retrospectively reviewed, and a total of 133 cystic cases were included in the present study. MR images and pathological features of all subjects were examined. Among the 133 cystic sellar-suprasellar masses, there were 78 cases of pituitary adenomas, 31 cases of craniopharyngioma, 21 cases of RCC, one case of epidermoid cyst and two cases of abscess. Fluid-fluid levels were identified n 43 cases (55.13%) of cystic pituitary adenomas, with a single fluid level in 23 cases, two fluid levels in 8 cases, and three levels or more in 12 cases. Two cases (6.45%) of craniopharyngioma, and one case (4.76%) of RCC presented single fluid level. No instances of fluid-fluid levels were observed in epidermoid cyst or abscess. Fluid-fluid levels were typically exhibited on axial T2-weighted images. The identification of fluid-fluid level in cysts provides useful diagnostic value in distinguishing pituitary adenoma from other sellar-suprasellar lesions. The findings of the present study suggest that a sellar-suprasellar mass with a fluid-fluid level inside the tumor is most likely a pituitary adenoma, particularly if multiple fluid levels are observed in the same tumor. The fluid-fluid level is typically clearly depicted on axial or sagittal MR images, suggesting subacute or chronic hemorrhage in pituitary adenomas.

Classical and non-classical causes of GH deficiency in the paediatric age

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.

Pituitary apoplexy: pathophysiology, diagnosis and management

Pituitary apoplexy is characterized by sudden increase in pituitary gland volume secondary to ischemia and/or necrosis, usually in a pituitary adenoma. Most cases occur during the 5th decade of life, predominantly in males and in previously unknown clinically non-functioning pituitary adenomas. There are some predisposing factors as arterial hypertension, anticoagulant therapy and major surgery. Clinical picture comprises headache, visual impairment, cranial nerve palsies and hypopituitarism. Most cases improve with both surgical and expectant management and the best approach in the acute phase is still controversial. Surgery, usually by transsphenoidal route, is indicated if consciousness and/or vision are impaired, despite glucocorticoid replacement and electrolyte support. Pituitary function is impaired in most patients before apoplexy and ACTH deficiency is common, which makes glucocorticoid replacement needed in most cases. Pituitary deficiencies, once established, usually do not recover, regardless the treatment. Sellar imaging and endocrinological function must be periodic reevaluated.

Extra-axial brain tumors

Extra-axial brain tumors are the most common adult intracranial neoplasms and encompass a broad spectrum of pathologic subtypes. Meningiomas are the most common extra-axial brain tumor (approximately one-third of all intracranial neoplasms) and typically present as slowly growing dural-based masses. Benign meningiomas are very common, and may occasionally be difficult to differentiate from more aggressive subtypes (i.e., atypical or malignant varieties) or other dural-based masses with more aggressive biologic behavior (e.g., hemangiopericytoma or dural-based metastases). Many neoplasms that typically affect the brain parenchyma (intra-axial), such as gliomas, may also present with primary or secondary extra-axial involvement. This chapter provides a general and concise overview of the common types of extra-axial tumors and their typical imaging features.

Endoscopic Endonasal Transsphenoidal Treatment of Pituitary Apoplexy: Outcomes in a Series of 20 Patients

Objective: Pituitary apoplexy is a rare clinical entity and few cases treated with an endonasal endoscopic approach (EEA) have been reported. We report our experience of treating pituitary apoplexy using an EEA approach.

Methods: We performed a retrospective chart review on all the patients who underwent EEA skull base and pituitary surgery between December 2003 and March 2012 performed by the senior authors (THS and VKA) and identified patients with pituitary apoplexy. The extent of resection was determined volumetrically and the visual and endocrine outcome was evaluated. 

Results: From a total of 488 skull base surgeries, there were 241 pituitary cases, of which 20 had apoplexy. The most common presenting symptoms included headaches (80%), endocrinopathy (95%), and visual symptoms (60%). Surgery was performed within 24 hours in 15% of patients, and > one month after ictus in 40% due to late referral. Gross-total resection (GTR) was achieved in 18 (90%) patients. There was one (5%) postoperative cerebrospinal fluid (CSF) leak treated with lumbar drainage. Of 12 patients with preoperative visual disturbances, seven had improvements. For those patients with visual field cuts, only 33.3% showed improvement. There was no postoperative visual deterioration. Two patients developed new transient postoperative diabetes insipidus (DI) but there was no new permanent DI. The mean duration of follow-up was 22 months (range: 6 days – 72 months).

Conclusion: The endoscopic endonasal transsphenoidal approach is an effective modality to treat pituitary apoplexy with a high rate of GTR and minimal risk. Delayed surgery may result in lower rates of visual field defect improvement.

Primary meningeal melanocytoma of the sellar region: review of the literature and differential diagnosis with special reference to angiographical features

PURPOSE

Primary intracranial melanocytomas are rare neoplasms, especially in the sellar region. Intracranial melanocytoma is usually a dural-based tumor, fed by dural arterial branches in a manner similar to meningioma. Primary sellar melanocytoma may be misdiagnosed as hemorrhagic pituitary macroadenoma, spindle cell oncocytoma, and intrasellar meningioma. These tumors differ in some radiological respects, but are difficult to differentiate preoperatively.

METHODS

Only five cases of primary sellar/suprasellar melanocytic tumors, excluding melanomas have been reported thus far. In this paper, we report an instructive new case of a 31-year-old woman presenting with a 2-year history of amenorrhea and an intrasellar mass with suprasellar extension, suggestive of hemorrhagic pituitary adenoma.

RESULTS

Transsphenoidal surgical excision was difficult due to extensive bleeding from the lesion, and at the time, the tumor could not be diagnosed histopathologically. Six years later, we operated again because of tumor regrowth. Angiography revealed a hypervascular tumor, which was fed from the dorsal sellar floor. We had difficulty resecting the tumor, but achieved total removal. Our case had typical radiographic characteristics of melanocytoma, revealed by both magnetic resonance imaging and angiography. However, it was difficult to reach a final diagnosis. Further histopathological examination, including immunohistochemical and ultrastructural studies, was helpful for diagnosis of melanocytoma.

CONCLUSIONS

Primary sellar melanocytic tumors are derived from melanocytes in the meningeal lining of the sellar floor or in the diaphragm sellae, based on both embryological assumptions and the clinical findings of our case. We discuss the problems of differential diagnosis and management of primary sellar melanocytic tumors.

Differentiation between Cystic Pituitary Adenomas and Rathke Cleft Cysts: A Diagnostic Model Using MRI

BACKGROUND AND PURPOSE

Cystic pituitary adenomas may mimic Rathke cleft cysts when there is no solid enhancing component found on MR imaging, and preoperative differentiation may enable a more appropriate selection of treatment strategies. We investigated the diagnostic potential of MR imaging features to differentiate cystic pituitary adenomas from Rathke cleft cysts and to develop a diagnostic model.

MATERIALS AND METHODS

This retrospective study included 54 patients with a cystic pituitary adenoma (40 women; mean age, 37.7 years) and 28 with a Rathke cleft cyst (18 women; mean age, 31.5 years) who underwent MR imaging followed by surgery. The following imaging features were assessed: the presence or absence of a fluid-fluid level, a hypointense rim on T2-weighted images, septation, an off-midline location, the presence or absence of an intracystic nodule, size change, and signal change. On the basis of the results of logistic regression analysis, a diagnostic tree model was developed to differentiate between cystic pituitary adenomas and Rathke cleft cysts. External validation was performed for an additional 16 patients with a cystic pituitary adenoma and 8 patients with a Rathke cleft cyst.

RESULTS

The presence of a fluid-fluid level, a hypointense rim on T2-weighted images, septation, and an off-midline location were more common with pituitary adenomas, whereas the presence of an intracystic nodule was more common with Rathke cleft cysts. Multiple logistic regression analysis showed that cystic pituitary adenomas and Rathke cleft cysts can be distinguished on the basis of the presence of a fluid-fluid level, septation, an off-midline location, and the presence of an intracystic nodule (P = .006, .032, .001, and .023, respectively). Among 24 patients in the external validation population, 22 were classified correctly on the basis of the diagnostic tree model used in this study.

CONCLUSIONS

A systematic approach using this diagnostic tree model can be helpful in distinguishing cystic pituitary adenomas from Rathke cleft cysts.

Pituitary tumor apoplexy

We review the etiology, investigations, management and outcomes of pituitary tumor apoplexy. Pituitary tumor apoplexy is a clinical syndrome which typically includes the acute onset of headache and/or visual disturbance, cranial nerve palsy and partial or complete endocrine dysfunction. It is associated with either infarction or hemorrhage of a pre-existing pituitary adenoma and is associated with significant morbidity and potential fatality. Not all patients will present with classic signs and symptoms, therefore it is pertinent to appreciate the clinical spectrum in which this condition can present.

Pituitary apoplexy: an update on clinical and imaging features

Pituitary apoplexy (PA) is a rare and potentially fatal clinical condition presenting acute headache, vomiting, visual impairment, ophthalmoplegia, altered mental state and possible panhypopituitarism. It mostly occurs in patients with haemorrhagic infarction of the pituitary gland due to a pre-existing macroadenoma. Although there are pathological and physiological conditions that may share similar imaging characteristics, both clinical and imaging features can guide the radiologist towards the correct diagnosis, especially using magnetic resonance imaging (MRI). In this review, we will describe the main clinical and epidemiological features of PA, illustrating CT and MRI findings and discussing the role of imaging in the differential diagnosis, prognosis and follow-up. Teaching points • Headache, ophtalmoplegia and visual impairment are frequent symptoms of pituitary apoplexy. • CT is often the first imaging tool in PA, showing areas of hyperdensity within the sellar region. • MRI could confirm haemorrhage within the pituitary gland and compression on the optic chiasm. • Frequent simulating conditions are aneurysms, Rathke cleft cysts, craniopharingioma and mucocele. • The role of imaging is still debated and needs more studies.

Lesions of the ovary with T1-hypersignal

Pelvic magnetic resonance imaging (MRI) has been used successfully to diagnose ovarian masses that cannot be adequately evaluated using pelvic ultrasound. T1 hyperintensity is a common finding in an ovarian mass and has important diagnostic implications. The aims of this review are to list the substances that may produce high signal intensity on T1-weighted MRI, to explain the physical basis for causes of the high T1 signal intensity, and to describe common and uncommon T1 hyperintense ovarian lesions. The morphological findings, the imaging features of the additional sequences, and clinical variables can help in the differential diagnosis, and in some cases, enable a specific diagnosis, leading to appropriate management of the patient.

Impact of subclinical haemorrhage on the pituitary gland in patients with pituitary adenomas

OBJECTIVE

Advanced magnetic resonance imaging (MRI) and optical instruments for surgery frequently demonstrate subclinical haemorrhage in pituitary adenomas; however, the effects of subclinical haemorrhage on pituitary glands remain unclear. We sought to clarify the pituitary function in patients with subclinical pituitary adenoma haemorrhage (SPAH).

DESIGN/PATIENTS

Between January 2006 and December 2012, we retrospectively reviewed 328 consecutive patients who underwent surgery for pituitary adenoma. SPAH was defined as an intratumoral haemorrhage based on both 3 tesla MRI and operative findings, with no clinical symptoms of acute pituitary adenoma apoplexy. The pituitary dysfunction assessed using pre- and postoperative provocative tests was investigated in patients categorized into three groups: nonapoplectic adenoma, adenoma with SPAH and adenoma with clinical apoplexy.

MEASUREMENTS

The main outcome measure was the incidence of pituitary dysfunction.

RESULTS

The overall incidence of nonapoplectic adenomas, adenomas with SPAH and adenomas with clinical apoplexy was 82·3%, 14·3% and 3·4%, respectively. Clinical pituitary apoplexy frequently occurred in male patients with large nonfunctioning adenomas, causing pituitary dysfunction. Contrastingly, the incidence of SPAH was significantly higher in the patients with prolactinoma (P = 0·0260), including those with relatively small adenomas (P = 0·0007). No medications, such as dopamine agonists or somatostatin analogues, were observed to affect the occurrence of SPAH. No deterioration of the pituitary function was observed in the SPAH patients in comparison with the patients with nonapoplectic adenoma, and the size of the haematoma occupying the pituitary adenoma did not exhibit any relationships with the deterioration of the pituitary function. Furthermore, SPAH caused no deterioration of the pituitary function after a surgery based on the postoperative provocation tests.

CONCLUSIONS

Subclinical pituitary adenoma haemorrhage does not cause any added dysfunction in pituitary glands. Signs of haemorrhage in pituitary adenomas do not necessitate immediate tumour decompression surgery, if there are no symptoms of acute haemorrhage.

Normal dimensions of the posterior pituitary bright spot on magnetic resonance imaging

Object

The normal pituitary bright spot seen on unenhanced T1-weighted MRI is thought to result from the T1-shortening effect of the vasopressin stored in the posterior pituitary. Individual variations in its size may be difficult to differentiate from pathological conditions resulting in either absence of the pituitary bright spot or in T1-hyperintense lesions of the sella. The objective of this paper was to define a range of normal dimensions of the pituitary bright spot and to illustrate some of the most commonly encountered pathologies that result in absence or enlargement of the pituitary bright spot.

Methods

The authors selected normal pituitary MRI studies from 106 patients with no pituitary abnormality. The size of each pituitary bright spot was measured in the longest axis and in the dimension perpendicular to this axis to describe the typical dimensions. The authors also present cases of patients with pituitary abnormalities to highlight the differences and potential overlap between normal and pathological pituitary imaging.

Results

All of the studies evaluated were found to have pituitary bright spots, and the mean dimensions were 4.8 mm in the long axis and 2.4 mm in the short axis. The dimension of the pituitary bright spot in the long axis decreased with patient age. The distribution of dimensions of the pituitary bright spot was normal, indicating that 99.7% of patients should have a pituitary bright spot measuring between 1.2 and 8.5 mm in its long axis and between 0.4 and 4.4 mm in its short axis, an interval corresponding to 3 standard deviations below and above the mean. In cases where the dimension of the pituitary bright spot is outside this range, pathological conditions should be considered.

Conclusions

The pituitary bright spot should always be demonstrated on T1-weighted MRI, and its dimensions should be within the identified normal range in most patients. Outside of this range, pathological conditions affecting the pituitary bright spot should be considered.