DOTATATE PET/MR Imaging Differentiates Secondary-Progressive from de Novo World Health Organization Grade 3 Meningiomas.

BACKGROUND AND PURPOSE: WHO grade 3 meningiomas are rare and poorly understood and have a higher propensity for recurrence, metastasis, and worsened clinical outcomes compared with lower-grade meningiomas. The purpose of our study was to prospectively evaluate the molecular profile, PET characteristics, and outcomes of patients with World Health Organization grade 3 meningiomas who were imaged with gallium 68 (68Ga) DOTATATE PET/MR imaging. MATERIALS AND METHODS: Patients with World Health Organization grade 3 meningiomas enrolled in our prospective observational cohort evaluating the utility of (68Ga) DOTATATE PET/MR imaging in somatostatin receptor positive brain tumors were included. We stratified patients by de novo-versus-secondary-progressive status and evaluated the differences in the PET standard uptake value, molecular profiles, and clinical outcomes. RESULTS: Patients met the inclusion criteria (secondary-progressive: 7/14; de novo: 7/14). The secondary-progressive cohort had a significantly higher per-patient number of surgeries (4.1 versus 1.6; P = .011) and trended toward a higher number of radiation therapy courses (2.4 versus 1.6; P = .23) and cumulative radiation therapy doses (106Gy versus 68.3Gy; P = .31). The secondary-progressive cohort had a significantly lower progression-free survival compared with the de novo cohort (4.8 versus 37.7 months; P = .004). Secondary-progressive tumors had distinct molecular pathology profiles with higher numbers of mutations (3.5 versus 1.2; P = .024). Secondary-progressive tumors demonstrated higher PET standard uptake values (17.1 versus 12.4; P = .0021). CONCLUSIONS: Our study confirms prior work illustrating distinct clinical outcomes in secondary-progressive and de novo World Health Organization grade 3 meningiomas. Furthermore, our findings support (68Ga) DOTATATE PET/MR imaging as a useful management strategy in World Health Organization grade 3 meningiomas and provide insight into meningioma biology, as well as clinical management implications.

[68 Ga]-DOTATATE PET/MR-based evaluation of physiologic somatostatin receptor 2 expression in the adult pituitary gland as a function of age and sex in a prospective cohort.

PURPOSE: The pituitary gland has the fourth highest physiologic avidity of [68 Ga]-DOTATATE. In order to guide our understanding of [68 Ga]-DOTATATE PET in clinical contexts, accurate characterization of the normal pituitary gland is first required. This study aimed to characterize the normal pituitary gland using dedicated brain [68 Ga]-DOTATATE PET/MRI as a function of age and sex. METHODS: A total of 95 patients with a normal pituitary gland underwent brain [68 Ga]-DOTATATE PET examinations for the purpose of diagnosing CNS SSTR2 positive tumors (mean age: 58.9, 73% female). Maximum SUV of the pituitary gland was obtained in each patient. SUV of superior sagittal sinus was obtained to calculate normalized SUV score (SUVR) of the gland. The anatomic size of the gland was collected as maximum sagittal height (MSH). Correlations with age and sex were analyzed. RESULTS: The mean SUV and SUVR of the pituitary gland were 17.6 (range: 7-59.5, SD = 7.1) and 13.8 (range: 3.3-52.6, SD = 7.2), respectively. Older females had significantly higher SUV of the pituitary gland compared to younger females. When stratified by age and sex, both older and younger females had significantly higher pituitary SUV than older males. SUVR did not differ significantly by age or sex. MSH of the pituitary gland in younger females was significantly greater than in younger males at all age cutoffs. CONCLUSION: This study provides an empiric profiling of the physiological [68 Ga]-DOTATATE avidity of the pituitary gland. The findings suggest that SUV may vary by age and sex and can help guide the use of [68 Ga]-DOTATATE PET/MRI in clinical and research settings. Future studies can build on these findings to investigate further the relationship between pituitary biology and demographic factors.