| Purpose: To investigate the role of diffusion weighted imaging(DWI) and perfusion weighted imaging(PWI) in the differentiation diagnosis of cerebellar tumors. Materials and methods: 122 patients with histologically confirmed cerebellar tumors[19 medulloblastomas, 19 pilocytic astrocytomas, 24 hemangioblastomas, 37 brain metastases, 8 primary central nervous system lymphomas, 11 gradeⅡgliomas(5 ependymomas, 6 gradeⅡastrocytomas or oligodendroglioma), 4 anaplastic astrocytomas or oligodendroglioma] were included in this study between Oct 2009 and Dec 2016. Conventional MR imaging, DWI were performed preoperatively on a SIEMENS Verio 3.0T scanner in all patients. PWI were performed in 56 patients(7 medulloblastomas, 10 pilocytic astrocytomas, 17 hemangioblastomas, 16 brain metastases, 6 primary central nervous system lymphoma). The apparent diffusion coefficient(ADC) values and cerebral blood volume(CBV) values were acquired from solid contrast-enhancing regions of the lesions and the contralateral normal-appearing cerebellar white matter on ADC and CBV maps respectively. The relative minimum apparent diffusion coefficient(r ADCmin) and relative maximum cerebral blood volume(r CBVmax) parameters of the solid contrast-enhanced portions of the lesions were calculated. The r ADCmin values were analyzed by using Welch test and Mann-Whitney U test. The r CBVmax values were analyzed by using one-way ANOVA and Least-Significant Difference test. Results1. The r ADCmin values of the solid portion were highest in hemangioblastomas(2.36±0.71), while r ADCmin values were lowest in medulloblastomas(0.80±0.13). There were significantly differences among different types of cerebellar tumors in r ADCmin values(F=25.75,P<0.05).2.The r ADCmin values in the solid portions of hemangioblastomas and pilocytic astrocytomas were significantly higher than that of medulloblastoams, brain metastases, primary central nervous system lymphomas and gradeⅡgliomas(P<0.05) respectively. But there were no statistically differences between hemangioblastomas and pilocytic astrocytomas in the ADCmin values(P=0.88).3. The r ADCmin values in the solid portions of medulloblastoams and primary central nervous system lymphoma were significantly lower than that of hemangioblastomas, pilocytic astrocytomas, brain metastases, and gradeⅡgliomas(P<0.05) respectively. But there were no statistically differences between medulloblastoams and primary central nervous system lymphomas in the ADCmin values(P=0.46).4. The r CBVmax values of the contrast-enhanced solid portions were highest in hemangioblastomas(7.72±1.31), while r CBVmax values were lowest in lymphomas(2.06±1.12). There were significantly differences among different types of cerebellar tumors in r CBVmax values(F=40.52,P<0.05).5. The r CBVmax values in hemangioblastomas were significantly higher than that of other cerebellar tumors respectively(P<0.05). There was no statistically differences between medulloblastomas and other cerebellar tumors(except hemangioblastomas) in the r CBVmax values(P>0.05).6. There was significantly differences in the r CBVmax values between pilocytic astrocytomas and brain metastases(P<0.05). There was also significantly differences in the r CBVmax values between lymphomas and brain metastases(P<0.05). Conclusion: DWI and PWI could provide the tissue structure and microvasculature information of tumors respectively, which can be helpful in the preoperative differentiation of different types of cerebellar tumors. |
