Predicting Subtype of Growth Hormone Pituitary Adenoma based on Magnetic Resonance Imaging Characteristics

Abstract

This study aimed to investigate the value of magnetic resonance (MR) characteristics in differentiating the subtypes of growth hormone pituitary adenomas. Materials and Methods:The clinical and MR imaging data of 70 patients with growth hormone pituitary adenoma confirmed by surgery and pathology were retrospectively analyzed. The tumors were divided into dense granular (DG; 36 cases) and sparse granular subtypes (SG; 34 cases). The tumors' MR features were analyzed, including the mean and maximum diameters, T2 signal intensity, T2 relative signal intensity (rSI), homogeneity, enhancement degree, and invasiveness (Knosp grade). Mann-Whitney U test and χ 2 test were used to analyze MR characteristics between the 2 groups. The independent predictors and predictive probabilities of tumor subtypes were obtained via a logistic regression model, and the efficacy was compared by receiver operating characteristic curve. Results:The mean and maximum diameters of growth hormone adenoma in DG and SG were 1.77 versus 2.45 and 1.95 versus 3.00 cm (median, P < 0.05), respectively. There was a significant difference between the 2 groups in T2 signal intensity and rSI ( P values were 0.02 and 0.001, respectively). Most DG adenomas (86.1%) appeared as hypointense on T2 images, and 38.2% of SG adenomas were hyperintense. There was no significant difference in tumor homogeneity ( P = 0.622). A significant difference was found in the Knosp grade between the 2 subtypes ( P = 0.004). In addition, the enhancement degree of SG adenomas was significantly higher than that of DG adenomas ( P = 0.001). Logistic regression analysis showed that high T2 rSI value and marked contrast enhancement were independent predictors of the 2 subtypes, and the odds ratios were 4.811 and 4.649, respectively. The multivariate logistic model obtained relatively high predicting ef-ficacy, and the area under the curve, sensitivity, and specificity were 0.765, 0.882, and 0.500, respectively.Conclusions: There are significant differences in tumor size, T2 signal intensity, T2 rSI, enhancement degree, and invasiveness between DG and SG adenomas. The logistic model based on the marked contrast enhancement and high T2 rSI value has an important value in predicting the subtype of growth hormone adenoma.

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

“…The hypointensity compared to the gray matter on T2WI is considered to be characteristic of densely granulated tumors [ 82 ]. Densely granulated tumors often have a weaker contrast enhancement than sparsely granulated tumors [ 83 ]. In a report examining the signal enhancement rate of PitNETs/pituitary adenomas relative to normal brain tissue (putamen) during the early (within 39 s) and delayed (195 s) phases of dynamic MRI, GH-producing tumors had lower contrast enhancement rates than other PitNETs/pituitary adenomas in both the early and delayed phases, suggesting that the signal enhancement rate on dynamic MRI may be a useful parameter for distinguishing GH-producing PitNETs/pituitary adenomas from other PitNETs/pituitary adenomas [ 84 ].…”

Predictors of morphofunctional features of somatotrophic tumors and of the effectiveness of treatment with first-generation somatostatin receptor ligands

“…В последние годы активно обсуждается тема применения в клинической практике показателя ОИОС на Т2-ВИ в качестве предиктора морфофункциональной организации СО и чувствительности к лечению АС1 [25][26][27]. Предполагается, что гипоинтенсивный сигнал является маркером грануляции и указывает на присутствие ПСО, тогда как повышение интенсивности опухолевого сигнала коррелирует с числом клеток, содержащих ФТ [9,28].…”

Multidisciplinary management of difficult/aggressive growth-hormone pituitary neuro-endocrine tumors

“…Large tumor size, extra-sellar extension, and postoperative residues are generally considered to be predictors of poor outcome. A diameter that is > 15 mm has been reported in aggressive GH tumors ( 12 ) and has been detected mostly in sparsely granulated lesions ( 17 ). Aggressive GH-adenomas/PitNET show specific patterns of growth.…”

“…The tumor’s relation to the cavernous sinus is classically quantified by Knosp scoring on MRI, which measures lateral tumor extension in relation to the internal carotid arteries preoperatively ( 21 , 22 ). If compared to densely granulated (DS) GH-secreting PitNETs, sparsely granulated (SG) tumors are more likely to invade the cavernous sinus (grades 3–4 of Knosp’s classification) ( 17 ).Some MRI sequences and techniques may help to predict the more SG phenotype of GH secreting PitNET: high T2 signal intensity, due to a low collagen content and low number of secreted granules, and a more avid enhancement are found in SG adenomas ( 17 ). T2WI-based texture parameters of the whole tumor appear to be able to provide more quantitative information and help predict granulation pattern better than T2 signal intensity ( 23 ).…”