Post-operative imaging assessment of non-functioning pituitary adenomas

Surveillance Imaging Strategies for Pituitary Adenomas: When, How Frequent, and When to Stop

OBJECTIVE

To describe a practical approach of when and how often to perform imaging, and when to stop imaging pituitary adenomas (PAs).

METHODS

A literature review was carried out and recommendations provided are derived largely from personal experience.

RESULTS

Magnetic resonance imaging is the mainstay imaging modality of choice in the assessment, treatment planning, and follow-up of PAs. These adenomas are discovered incidentally during imaging for a variety of unrelated conditions, because of clinical symptoms related to mass effects on the adjacent structures, or during workup for functional alterations of the adenoma. Imaging is also used in the preoperative and postoperative phases of assessment of PAs, for surgical and radiotherapy planning, for postoperative surveillance to assess for adenoma stability and detection of adenoma recurrence, and for surveillance to monitor for adenoma growth in unoperated PAs. Currently, because there are no evidence-based consensus recommendations, the optimal strategy for surveillance imaging of PAs is not clearly established. Younger age, initial adenoma size, extrasellar extension, mass effect, cavernous sinus invasion, functional status, histopathologic characteristics, cost considerations, imaging accessibility, patient preference, and patient contraindications (eg, implanted metallic devices and patient claustrophobia) are all important factors that influence the strategy for surveillance imaging.

CONCLUSIONS

This review provides a practical approach of performing surveillance imaging strategies for PAs that should be individualized based on clinical presentation, history, adenoma morphology on imaging, and histopathologic characteristics.

Magnetic resonance imaging characteristics of residual pituitary tissues following transsphenoidal resection of pituitary macroadenomas

Objective

The present study is to investigate the pre- and post-operative magnetic resonance imaging of pituitary tissues following transsphenoidal resection of pituitary macroadenomas, as well as its clinical significance.

Materials and Methods

The medical records of 108 consecutive pituitary macroadenoma patients admitted at Fuzhou 900th Hospital between September 2012 and September 2014 were retrospectively reviewed. Siemens 3. 0T magnetic resonance scanner was used to perform pre- and postoperative MRI scanning, including plain scan and contrast-enhanced scan of SE sequential T1WI and T2WI in sagittal, coronal and axial views. PACS medical imaging system was used to measure the diameter of pituitary adenoma, as well as the volumes of the adenoma and pituitary tissue. Hematoxylin-eosin staining and immunohistochemical staining were also performed.

Results

Higher height of pituitary adenoma results in lower rate of posterior pituitary bright spot (PPBS) on MR T1-weighted imaging. Preoperative MR signal intensity of PPBS was negatively related to diabetes insipidus (DI). Normal pituitary tissues were likely to be above the pituitary adenomas in growth hormone-secreting adenoma patients, while mostly located aside in gonadotropin-secreting adenoma patients. Morphological restitution of postoperative pituitary tissues was better in lateral displacement than that in superior or superolateral patterns on pre-operative MR images. Positive rate of PPBS on preoperative MRI is negatively related to adenoma height, and the signal intensity of PPBS is inversely related to postoperative DI.

Conclusions

The relative locations of pituitary tissues and adenoma tissues may be associated with the adenoma type and may affect the postoperative remodeling of residual pituitary tissues.

Diffusion-weighted imaging for predicting tumor consistency and extent of resection in patients with pituitary adenoma

This study aimed to investigate the role of diffusion-weighted imaging (DWI) in predicting tumor consistency, extent of surgical resection, and recurrence in pituitary adenoma (PA). We reviewed a prospectively collected database of surgically treated PA between March 2016 and October 2017. Predictors for extent of resection and recurrence/progression were assessed with logistic and Cox regression analysis. Of the 183 patients, the tumor consistency was found soft in 107 (58.5%) patients, intermediate in 41 (22.4%) patients, and hard in 35 (19.1%) patients. The mean of ADC ratio was 0.92 ± 0.22 for hard tumor, 1.03 ± 0.22 for intermediate tumor, and 1.41 ± 0.62 for soft tumor (P < 0.001). The mean collagen content was 25.86% ± 15.00% for hard tumor, 16.05% ± 9.90% for intermediate tumor, and 5.00% ± 6.00% for soft tumor (P < 0.001). Spearman analysis showed a significant correlation between ADC ratio and collagen content (ρ = - 0.367; P < 0.001). Gross-total resection (GTR) was obtained in 68.3% of patients, and multivariable logistic regression analysis showed that ADC ratio (OR, 12.135; 95% CI, 4.001-36.804; P < 0.001), giant PA (OR, 0.233; 95% CI, 0.105-0.520; P < 0.001), and invasion (OR, 0.459; 95% CI, 0.220-0.960; P = 0.039) were significantly predictive of GTR. Twenty-seven (14.8%) patients suffered recurrence/progression in the mean follow-up of 35.14 months. Invasion (HR, 2.728; 95% CI, 1.262-5.899; P = 0.011) was identified as independent predictors of recurrence/progression. ADC ratio of DWI could be used for preoperative assessment of tumor consistency, tumor collagen content, and extent of surgical resection, which might be useful in preoperative planning for patients with PA.

Practice patterns in the management of recurrent and residual non-functioning pituitary adenomas: Results from a Canada-wide survey

Background

There is no consensus regarding the management and postoperative follow-up of non-functioning pituitary adenomas (NFAs) in the setting of recurrent or residual disease. Subsequent treatment options include continued follow-up, re-resection or radiotherapy. To address this gap and better understand current practice patterns, we surveyed neurosurgeons and radiation oncologists in Canada.

Methods

Neurosurgeons and radiation oncologists (ROs) across Canada were invited to complete a standardized online questionnaire. Summary statistics were computed, and Fisher's Exact tests were performed to assess significance. Qualitative analyses were performed through open and axial coding.

Results

Thirty-three participants completed the questionnaires, with neurosurgeons representing a majority of respondents (n = 20 vs n = 13). When treating giant (>3 cm) tumors, 90.9% of neurosurgeons in practice for less than 10 years reported using an endoscopic approach, as compared to only 66.7% of neurosurgeons in practice for 10 years of more. Additionally, neurosurgeons who were newer to practice had a greater tendency to advocate for stereotactic radiosurgery (SRS) or re-resection (54.5% and 36.4%, respectively), as compared to older surgeons who showed a higher propensity (22.2%) to advocate for observation. The presence of cavernous sinus extension appeared to encourage ROs to offer radiotherapy sooner (61.4%), as compared to 40% of neurosurgeons.

Conclusions

Our results identified both variations and commonalities in practice amongst Canadian neurosurgeons. Approaches deviated in the setting of residual tumor based on years of practice. This work provides a critical foundation for future studies aiming to define evidence-based best practices in the management of NFAs.

•

No consensus in treatment of residual/recurrent non-functioning pituitary adenomas

•

Younger physicians prefer radiotherapy compared to senior physicians.

•

Skull base neurosurgeons advocate more aggressively for re-resection.

•

There is a need for standardization of treatment guidelines.