Neuroimaging Features Of The Intracranial Germinoma In Different Locations

Objective: To investigate the the CT and MRI features of the intracranial germinoma with different locations and to improve the understanding about this entity.Methods: Forty one cases of intracranial germinoma verified by pathology or clinical treatment were included in this study. Plain and enhanced MRI scanning were performed in all of these patients, in which 26 cases also underwent CT scanning. The imaging characteristics including direct sign and indirect sign were observed and analyzed. The imaging characteristics including direct sign and indirect sign were observed and analyzed, and the proportion of each imaging sign in different locations were recorded. The direct signs consisted of the intensity/signal, cacification, cystic the proportion in different leisions were recorded. The direct signs consisted of the intensity/signal, calcification, cystic degeneration and enhanced performance. The indirect signs consisted of wallerian degeneration and loss of the posterior pituitary bright spot on T1 sequences.Results: Of 41 cases, 32 males and 9 females, the age ranged from 1 to 14 years, with the mean age of(8.2±3.4) years. The lesions of 22 cases(53.6%) were located in pineal region, 11(26.8%) in sella region(including suprasellar), 4(9.7%) in thalamus and basal ganglion region, 2(4.8%) in encephalocoele, and 1(2.4%) in temporal lobe. All the cases above were detected with unifocal lesion. In addition, there was 1 case with multifocal lesions, which located in pineal region, suprasellar region(including sellar area), and thalamus and basal ganglion region respectively(counted as 3 cases in different lesions). The germioma parenchyma on plain CT images were dominated by hyperdense 72%(18/25), with calcification 76%(19/25), which was aparently higher than other locations in pineal region(18/20). The masses showed isointensity and hyperintensity on T1 WI in 35%(14/40) of the cases, isointensity and hypointensity on T2 WI in 38%(15/40), hyperintensity on DWI in 53%(19/36). The masses showed significant enhancement after the gadolinium administration in 87%(35/40) of the cases. The cystic degeneration was found in 53%(21/40) of the cases. The wallerian degeneration was found in 8%(3/33) of all the cases and was detected only in the basal ganglia and thalamus area, with a 60%(3/5) percentage. The loss of the posterior pituitary bright spot on T1 WI were specific for the germinomas located in the superasellar region(80%, 4/5), accounting for(12%, 4/33) of all cases. In all the above characteristics, there was significant difference in proportion of calcification, wallerian degeneration and loss of the posterior pituitary bright spot on T1 sequences in different locations(P=0.001, P=0.003 and P=0 respectively).Conclusion: Intracranial germinoma with different locations have some imaging features. These imaging features could be used to diagnose the intracranial germinoma accurately in an early stage.