Tumor consistency of pituitary macroadenomas: predictive analysis on the basis of imaging features with contrast-enhanced 3D FIESTA at 3T

Abstract

Background and purpose: Preoperative evaluation of pituitary macroadenoma tumor consistency is important for neurosurgery. Thus, we aimed to retrospectively assess the role of contrast-enhanced FIESTA in predicting the tumor consistency of pituitary macroadenomas.

Materials and methods: Twenty-nine patients with pituitary macroadenomas underwent conventional MR imaging sequences and contrast-enhanced FIESTA before surgery. Two neuroradiologists assessed the contrast-enhanced FIESTA, contrast-enhanced T1WI, and T2WI. On the basis of surgical findings, the macroadenomas were classified by the neurosurgeons as either soft or hard. Finally, Fisher exact probability tests and unpaired t tests were used to compare predictions on the basis of the MR imaging findings with the tumor consistency, collagen content, and postoperative tumor size.

Results: The 29 pituitary macroadenomas were classified as either solid or mosaic types. Solid type was characterized by a homogeneous pattern of tumor signal intensity without intratumoral hyperintense dots, whereas the mosaic type was characterized by many intratumoral hyperintense dots on each MR image. Statistical analyses revealed a significant correlation between tumor consistency and contrast-enhanced FIESTA findings. Sensitivity and specificity were higher for contrast-enhanced FIESTA (1.00 and 0.88-0.92, respectively) than for contrast-enhanced T1WI (0.80 and 0.25-0.33, respectively) and T2WI (0.60 and 0.38-0.54, respectively). Compared with mosaic-type adenomas, solid-type adenomas tended to have a hard tumor consistency as well as a significantly higher collagen content and lower postoperative tumor size.

Conclusions: Contrast-enhanced FIESTA may provide preoperative information regarding the consistency of macroadenomas that appears to be related to the tumor collagen content.

Fig 1.

Classification of pituitary macroadenomas by use of CE-FIESTA, CE-T1WI, and T2WI. 1, Solid type. Schematic drawing and coronal images of CE-FIESTA (A and B), CE-T1WI (C), and T2WI (D) show homogeneous patterns of SI without intratumoral hyperintense dots. 2, Mosaic type. Schematic drawing and coronal images of CE-FIESTA (A and B), CE-T1WI (C), and T2WI (D) show intratumoral hyperintense dots within the tumor.

Fig 2.

Macroadenoma with hard consistency in a 77-year-old male patient (case 13). A, Coronal CE-T1WI shows a large heterogeneous enhanced pituitary mass. B, Coronal T2WI shows an isointense mass with respect to normal white matter. C, Coronal CE-FIESTA shows a homogeneous tumor SI pattern without intratumoral hyperintense dots. D, Histologic examination of the resected tumor indicates small size and the formation of multiple nests surrounded by attenuated collagen tissue (Masson trichrome stain; scale bar, 200 μm).

Fig 3.

Macroadenoma with soft consistency in a 51-year-old female patient (case 28). A, Coronal CE-T1WI shows a large, homogeneous, enhanced pituitary mass. B, Coronal T2WI shows a relatively hyperintense mass with respect to normal white matter. C, Coronal CE-FIESTA shows numerous hyperintense dots within the tumor. D, Histologic examination of the resected tumor indicates small cells with scant collagen in a small, restricted perivascular area (Masson trichrome stain; scale bar, 200 μm).

Fig 4.

Macroadenoma with soft consistency in a 44-year-old female patient (case 29). A, Unenhanced coronal FIESTA image, and B, corresponding coronal CE-FIESTA image. Intratumoral hyperintense dots are shown on CE-FIESTA (arrows in B) but not on unenhanced FIESTA. C, Histologic examination of the resected tumor shows scant collagenous tissues in a perivascular area (Masson trichrome stain; scale bar, 200 μm).