Evaluation of pituitary macroadenomas with multidetector-row CT (MDCT): comparison with MR imaging

Imaging of pituitary tumors: an update with the 5th WHO Classifications-part 1. Pituitary neuroendocrine tumor (PitNET)/pituitary adenoma

The pituitary gland is the body's master gland of the endocrine glands. Although it is a small organ, many types of tumors can develop within it. The recently revised fifth edition of the World Health Organization (WHO) classifications (2021 World Health Organization Classification of Central Nervous System Tumors and 2022 World Health Organization Classification of Endocrine and Neuroendocrine Tumors) revealed significant changes to the classification of pituitary adenomas, the most common type of pituitary gland tumor. This change categorized pituitary adenomas as neuroendocrine tumors and proposed the name to be revised to pituitary neuroendocrine tumor (PitNET). The International Classification of Diseases for Oncology behavior code for this tumor was previously "0" for benign tumor. In contrast, the fifth edition WHO classification has changed this code to "3" for primary malignant tumors as same to neuroendocrine tumor in other organs. Because the WHO classification made an important and significant change in the fundamental concept of the disease, in this paper, we will discuss the imaging diagnosis (magnetic resonance imaging, computed tomography, and positron emission tomography) of PitNET/pituitary adenoma in detail, considering these revisions as per the latest version of the WHO classification.

Guidelines in the management of CNS tumors

INTRODUCTION

Evidence-based, clinical practice guidelines in the management of central nervous system tumors (CNS) continue to be developed and updated through the work of the Joint Section on Tumors of the Congress of Neurological Surgeons (CNS) and the American Association of Neurological Surgeons (AANS).

METHODS

The guidelines are created using the most current and clinically relevant evidence using systematic methodologies, which classify available data and provide recommendations for clinical practice.

CONCLUSION

This update summarizes the Tumor Section Guidelines developed over the last five years for non-functioning pituitary adenomas, low grade gliomas, vestibular schwannomas, and metastatic brain tumors.

Post-operative imaging assessment of non-functioning pituitary adenomas

BACKGROUND

Non-functioning pituitary adenomas (NFAs) are the most common pituitary tumors. There is significant variability in clinical practice in terms of post-operative imaging evaluation. The objective of this manuscript is to provide an exhaustive review of published articles pertaining to the post-operative imaging evaluation of NFAs.

METHODS

The MEDLINE database was queried for studies investigating imaging for the post-operative evaluation of pituitary adenomas. From an initial search of 5589 articles, 37 articles were evaluated in detail and included in this review.

RESULTS

Magnetic resonance imaging (MRI) is the gold standard for post-operative monitoring of NFAs, although functional imaging modalities may improve identification of residual tumor in conjunction with MRI. The residual tumor can be distinguished from post-operative changes by experienced practitioners using high-resolution MRI in the immediate post-operative setting (within 1 week of surgery). However, continued imaging evolution in the appearance of residual tumor or resection cavity is expected up to 3 months post-operatively.

CONCLUSIONS

Post-operative imaging appearance of the pituitary gland, optic apparatus, and pneumocephalus patterns, correlated with the clinical outcomes. Long-term, lifetime follow-up is warranted for NFA patients who underwent surgical resection.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guideline on Preoperative Imaging Assessment of Patients With Suspected Nonfunctioning Pituitary Adenomas

BACKGROUND

The authors reviewed published articles pertaining to the preoperative imaging evaluation of nonfunctioning pituitary adenomas (NFPAs) and formulated recommendations.

OBJECTIVE

To provide an exhaustive review of published articles pertaining to the preoperative imaging evaluation of nonfunctioning pituitary adenomas.

METHODS

The MEDLINE database was queried for studies investigating imaging for the preoperative evaluation of pituitary adenomas.

RESULTS

From an initial search of 5598 articles, 122 articles were evaluated in detail and included in this article. Based on analysis of these articles, the recommendations are as follows: (1) High-resolution magnetic resonance imaging (level II) is recommended as the standard for preoperative assessment of nonfunctioning pituitary adenomas, but may be supplemented with CT (level III) and fluoroscopy (level III). (2) Although there are promising results suggesting the utility of magnetic resonance spectroscopy, magnetic resonance perfusion, positron emission tomography, and single-photon emission computed tomography, there is insufficient evidence to make formal recommendations pertaining to their clinical applications.

CONCLUSION

The authors identified 122 articles that form the basis of recommendations for preoperative imaging evaluation of nonfunctioning pituitary adenomas. The full guidelines document for this chapter can be located at https://www.cns.org/guidelines/guidelines-management-patients-non-functioning-pituitary-adenomas/Chapter_2.

ABBREVIATIONS

CT, computed tomographyDWI, diffusion-weighted imagingMRI, magnetic resonance imagingNFPA, nonfunctioning pituitary adenoma.

Role of High-Resolution Dynamic Contrast-Enhanced MRI with Golden-Angle Radial Sparse Parallel Reconstruction to Identify the Normal Pituitary Gland in Patients with Macroadenomas

BACKGROUND AND PURPOSE

Preoperative localization of the pituitary gland with imaging in patients with macroadenomas has been inadequately explored. The pituitary gland enhancing more avidly than a macroadenoma has been described in the literature. Taking advantage of this differential enhancement pattern, our aim was to evaluate the role of high-resolution dynamic MR imaging with golden-angle radial sparse parallel reconstruction in localizing the pituitary gland in patients undergoing trans-sphenoidal resection of a macroadenoma.

MATERIALS AND METHODS

A retrospective study was performed in 17 patients who underwent trans-sphenoidal surgery for pituitary macroadenoma. Radial volumetric interpolated brain examination sequences with golden-angle radial sparse parallel technique were obtained. Using an ROI-based method to obtain signal-time curves and permeability measures, 3 separate readers identified the normal pituitary gland distinct from the macroadenoma. The readers' localizations were then compared with the intraoperative location of the gland. Statistical analyses were performed to assess the interobserver agreement and correlation with operative findings.

RESULTS

The normal pituitary gland was found to have steeper enhancement-time curves as well as higher peak enhancement values compared with the macroadenoma (P < .001). Interobserver agreement was almost perfect in all 3 planes (κ = 0.89). In the 14 cases in which the gland was clearly identified intraoperatively, the correlation between the readers' localization and the true location derived from surgery was also nearly perfect (κ = 0.95).

CONCLUSIONS

This study confirms our ability to consistently and accurately identify the normal pituitary gland in patients with macroadenomas with the golden-angle radial sparse parallel technique with quantitative permeability measurements and enhancement-time curves.

The use of image-guidance during transsphenoidal pituitary surgery in the United States

BACKGROUND

Intraoperative image guidance is a useful modality for transsphenoidal pituitary surgery. However, the outcomes associated with this technology have not been systematically evaluated.

OBJECTIVE

The purpose of the study was to quantify complication rates with and without the use of image guidance during transsphenoidal pituitary surgery using a nationwide database with broadly applicable results.

METHODS

A retrospective analysis of the Nationwide Inpatient Sample was performed from 2007 to 2011. Transsphenoidal pituitary resections for adenomas were identified by International Classification of Diseases-9th Revision, Clinical Modification code. The effect of image guidance on cerebrospinal fluid (CSF) leak complications and cost-benefit was analyzed.

RESULTS

A total of 48,848 transsphenoidal pituitary resections were identified, of which 77.5% were partial resections and 22.5% were complete. Pathologic indications included benign (89.3%), malignant primary (0.6%), and malignant secondary (0.4%). Complications included same-stay death (0.4%), CSF leak (8.8%), postoperative CSF rhinorrhea (1.9%), diabetes insipidus (12.4%), and meningitis (0.4%). Image guidance was employed in 7% (n = 3401) of all cases. When analyzed by modality, computed tomography (CT)-assisted procedures had lower CSF rhinorrhea rates (1.1%) compared with cases with no image guidance (1.9%), whereas magnetic resonance (MR)-assisted procedures had the highest rates (2.7%, χ2 p < 0.001). Rates of CSF leak demonstrated a similar pattern (CT 6.4%, no image guidance 8.9%, MR 9.2%, χ2 p < 0.001). CT-assisted surgery had significantly shorter length of stay (2.9 days) versus no image guidance (3.7 days, p < 0.001), lower total charges ($47,589 versus $62,629, p < 0.001), and lower total cost ($16,748 versus $20,530, p < 0.001).

CONCLUSIONS

CT-assisted surgery is associated with a lower rate of CSF leak, shorter length of stay, and lower cost compared with patients without image guidance. Further studies that control for severity and extent of disease are warranted to confirm this finding.

3D dynamic pituitary MR imaging with CAIPIRINHA: initial experience and comparison with 2D dynamic MR imaging

OBJECTIVES

To evaluate the validity of 3D dynamic pituitary MR imaging with controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA), with special emphasis on demarcation of pituitary posterior lobe and stalk.

METHODS

Participants comprised 32 patients who underwent dynamic pituitary MR imaging due to pituitary or parasellar lesions. 3D dynamic MR with CAIPIRINHA was performed at 3T with 20-s-interval, precontrast, 1st to 5th dynamic images. Normalized values and enhanced ratios (dynamic postcontrast image values divided by precontrast ones) were compared between 3D and 2D dynamic MR imaging for patients with visual identification of posterior lobe and stalk.

RESULTS

In 3D, stalk was identified in 29 patients and unidentified in 3, and posterior lobe was identified in 28 and unidentified in 4. In 2D, stalk was identified in 26 patients and unidentified in 6 patients, and posterior lobe was identified in 15 and unidentified in 17. Normalized values of pituitary posterior lobe and stalk were higher in 3D than 2D (P<0.001). No significant difference in enhancement ratio was seen between 3D and 2D.

CONCLUSIONS

3D dynamic pituitary MR provided better identification and higher normalized values of pituitary posterior lobe and stalk than 2D.

Evaluation of the sellar and parasellar regions

The article reviews the anatomy and imaging evaluation of the sellar and parasellar regions. Both common and uncommon sellar and suprasellar masses are reviewed, focusing on a systematic approach to analysis and when appropriate, differential creation.

Advances in pituitary imaging technology and future prospects

There have been substantial advances in pituitary imaging in the last half-century. In particular, magnetic resonance imaging is now established as the imaging modality of choice, providing high quality images of the hypothalamic-pituitary axis and adjacent structures. More recent technological advances, such as the emergence of 3 Tesla MRI, are already being widely incorporated into imaging practice. However, other advanced techniques, including a variety of potential imaging biomarkers, still require further research to evaluate their potential and define their precise role. The recent development of intraoperative MRI appears promising and may have the potential to improve the outcome of pituitary surgery. Modern high quality imaging inevitably leads to the discovery of incidental lesions, including those within the pituitary gland, although it also plays a central role in their subsequent evaluation and management.

Clival invasion on multi-detector CT in 390 pituitary macroadenomas: correlation with sex, subtype and rates of operative complication and recurrence

BACKGROUND AND PURPOSE

Clival invasion, a rare but potentially significant complication of pituitary adenoma, is difficult to detect on MR imaging. Because CT is widely used in adjunct guidance of pituitary surgery and it has recently been suggested that preoperative CT may add useful diagnostic information in addition to pituitary MR imaging, we performed the first large cross-sectional imaging study to define the image attributes, clinical correlates, and prognostic implications of clival invasion on CT for pituitary adenoma surgical guidance.

MATERIALS AND METHODS

Preoperative CT images from 390 patients with histopathologically diagnosed pituitary macroadenoma were reviewed retrospectively and classified by the presence and degree of clival invasion. Tumor volume, tumor subtype, patient sex, operative complication, and recurrence rates were compared between groups.

RESULTS

After we corrected for multiple correlations, the most significant independent risk factor for clival invasion was female sex (OR=3.62, P=.014, multinomial logistic regression), followed by large tumor volume (OR=1.08, P<.001), and null-cell subtype (OR=5.47, P<.001). Larger tumor volume correlated with null-cell subtype (Mann-Whitney U test, P=.006), incidence of clival invasion (P<.001), and extent of clival invasion (P=.038). Clival invasion was associated with a significantly higher ratio of operative complications (15.63%, χ(2)=7.067, P=.008) and recurrence (57.14%, χ(2)=10.739, P=.001).

CONCLUSIONS

CT detection of clival invasion by pituitary macroadenoma is significantly more common in women, in patients with large tumors, and in patients with null-cell tumors, and it is associated with a higher rate of operative complications and recurrences. Attention to the presence of clival invasion on preoperative CT and prospective investigation of its prognostic significance are indicated. Attention to this finding on pituitary guidance CT is warranted.

[Tumors in the region of the sella turcica]

Tumors of the pituitary gland can lead to limitation of hypophysis function (hypophysis insufficiency) or hypersecretion of different hormones (acromegaly, Cushing's syndrome, prolactinoma, TSH-secreting adenoma). The optic chiasma lies in close proximity to the pituitary gland and can be compressed by tumors leading to visual disturbances (bilateral hemianopsia). Tumors can be separated into hormone secreting and hormone inactive tumors, as well as into microadenoma with a diameter <10 mm and macroadenomas >10 mm. A rare group of tumors of the hypophysis region are craniopharyngiomas, meningiomas, germinomas, gliomas, metastases and granulomotous inflammations, such as sarcoidosis and tuberculosis.