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

Abstract

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.

Fig 1.

A, Contrast-enhanced sagittal T1WI demonstrates a macroadenoma. B, GRASP dynamic MR imaging through the sella demonstrates the macroadenoma extending into the right cavernous sinus. A focal area of increased enhancement is seen along the left lateral aspect of the lesions. C, Postprocessed MR permeability peak scan demonstrates a focal area of increased contrast uptake (ROI 1) from the left lateral aspect of the sella compared with the macroadenoma (ROI 2). D, The enhancement-time curve confirms that the normal pituitary gland, localized along the left lateral aspect of the sella, enhances earlier and more robustly than the macroadenoma.

Fig 2.

A, Contrast-enhanced sagittal T1WI through the sella demonstrates a heterogeneously enhancing lesion expanding the sella and extending into the suprasellar compartment, suggestive of a macroadenoma. B, Contrast-enhanced coronal T1WI demonstrates the macroadenoma. The heterogeneous enhancement within the lesion makes it difficult to localize the pituitary gland. C, GRASP dynamic study at 90 seconds (early dynamic phase) demonstrates more prominent enhancement along the left superolateral aspect of the lesion. D, Wash-in permeability study with ROIs placed within the central, heterogeneous portion of the lesion (ROI 2) and the more avidly enhancing region seen along its left superolateral aspect (ROI 1). E, Enhancement-time curves demonstrate a difference in rate and peak contrast uptake for each ROI. The ROI from the more avidly enhancing component seen along the left superolateral aspect of the lesion demonstrates a more pronounced peak enhancement than the more central, heterogeneously enhancing component. These curves validate that the pituitary gland is localized along the left superolateral aspect of this lesion, which was also confirmed at the operation.