Quantitative imaging values of CT, MR, and FDG-PET to differentiate pineal parenchymal tumors and germinomas: are they useful?

Abstract

None of the quantitative imaging values could differentiate PPTs from germinomas. Age, sex, and calcification patterns were confirmed useful in differentiating these tumors to some degree.

Pineal Region Tumors

“…67 Germinomas are generally small to moderate in size (1-3 cm). 43,68,69 On MRI (Figures 7 and 8), germinomas tend to be homogeneous in appearance and intermediate in signal on T2-weighted images (isointense to gray matter). At least a third of cases demonstrate coarse focal calcification engulfed by tumor ( Figure 6).…”

“…43,68,69 On MRI (Figures 7 and 8), germinomas tend to be homogeneous in appearance and intermediate in signal on T2-weighted images (isointense to gray matter). 51,69 The vector of tumor growth is usually in the ventral direction, with tumor encroachment or extension into the posterior aspect of the third ventricle. 54,70 ADC measures, if cystic foci within the tumor are excluded from the analysis, may show restricted diffusion in solid portions of tumor.…”

“…44,82 On DWI, a spectrum of ADC values is reported, but a propensity for low diffusivity ( Figures 12(C) and 13(B)), in keeping with a highly cellular tumor, is expected, especially when minimum ADC values are analyzed. 4,51,69 Generally, there is a tendency for these tumors to be isointense to gray matter on T2-weighted imaging. 44,51,82 CSF tumor dissemination at presentation can be seen and is reported in the range of 14-32%.…”

“…30,43,44,69,82,84 Pineocytomas are completely solid in 76% of cases and are typically medium-sized masses with a mean size of approximately 2.0 cm. NEURO-IMAGING OF BRAIN TUMORS peripherally dispersed.…”

“…NEURO-IMAGING OF BRAIN TUMORS peripherally dispersed. 30,44,52,56,69,82 The ADC values of pineocytomas overlap with other pineal tumors, but the minimum ADC values have been suggested to lie in the range of normal background parenchyma, unlike PPTIDs and pineoblastomas. 52 The typical MRI characteristics are those of a homogeneously enhancing solid mass, with a minority of cases having areas of cystic change and a few reported cases having pronounced cystic changes ( Figure 14).…”