Somatotroph pituitary tumor signal intensity in T-2 weighted pituitary MR images- quantitative assessment of the parameter and its clinical implications in consecutive newly-diagnosed patients with acromegaly.

M. Godlewska*^a (Ms), A. Grochowska^b (Dr), A. Bogusławska^b (Ms), A. Hubalewska-Dydejczyk^b (Prof), A. Gilis-Januszewska^b (Prof)

^a Jagiellonian University Medical College in Cracow, Krakow, POLAND ; ^b Jagiellonian University Medical College in Cracow, Cracow, POLAND

* magda.godlewska92@gmail.com

Introduction:

Intensity of the pituitary tumor in T2-weighted has been reported as a prognostic marker for tumor’s aggressiveness and poor response to 1^st generation somatostatin analogs.

Aim

The aim of this study was to quantitatively assess the tumor intensity of somatotroph pituitary tumors in T2-weighted MRI scans and investigate its clinical implications.

Methodology

72 consecutive patients with acromegaly between 01.01.2012 and 31.12.2021 at the Department of Endocrinology, Jagiellonian University Medical College were evaluated. Inclusion criteria were: biochemically confirmed acromegaly, sellar tumor confirmed in the pituitary MRI. 58 patients were found eligible for the study. Exclusion criterion was large cystic component preventing intensity measurement. Signal intensity of the solid part of the PitNET and grey matter of the temporal lobe were measured on T2-weighted pituitary MR images. Signal Intensity Ratio (SIR) of the PitNET to grey matter was calculated. Patients were divided into groups based on their SIR: hyperintensive tumors, with intensity higher than grey matter, isointensive tumors, with intensity higher than white matter, but lower than grey matter and hypointensive tumors, with intensity lower than intensity of white matter. IGF-1 to IGF-1 upper limit of the normal range for age and sex (IGF%ULN), tumor volume measured by manual delination of Volume of Interest, as well as age upon diagnosis were compared between the three groups.

Results

SIR was correlated weakly with tumor volume (R=0.265, p=0.04). No association between SIR and age upon diagnosis and IGF%ULN were found. Association of TV measurement and SIR did not reach the statistical significance (p=0.055). Median TV was 1.29 cm³ (IQR 4.16) for hyperintense tumors, 1.46 cm3 (IQR 1.7) for isointensive tumors and 0.65 cm3 (IQR 0.56) for hypointensive tumors. Post-hoc analysis showed, that the statistically significant difference was between hyperintensive and hypointensive tumors and between isointensive and hyperintensive tumors. No statistically significant differences were found between the isointensive tumors and hyperintensive tumors.

Conclusions: Both hyperintensive and isointensive tumors were larger than hypointensive tumors in our cohort. SIR was positively correlated with tumor size. Whether not only hyperintensive, but also isointensive tumors tend to have a more aggressive course of disease requires further investigation.

The author has declared no conflict of interest.