Elsevier

World Neurosurgery

Volume 110, February 2018, Pages e648-e652
World Neurosurgery

Original Article
Usefulness of 18F-fluorodeoxyglucose−Positron Emission Tomography in Comparison with Methionine−Positron Emission Tomography in Differentiating Solid Hemangioblastoma from Adult Cerebellar Tumors

https://doi.org/10.1016/j.wneu.2017.11.054Get rights and content

Background and Purpose

Among adults with posterior fossa tumors, an intraaxial location of the tumor is less common than an extraaxial location. Moreover, the differential diagnosis of a single cerebellar tumor in adults is sometimes difficult by conventional magnetic resonance imaging. We aimed to report the findings of positron emission tomography (PET) using 18F-fluorodeoxyglucose (FDG) and methionine in adult patients with intraaxial and solitary metastatic brain tumors.

Materials and Methods

FDG-PET was performed on 12 patients with posterior fossa tumors: 4 had solid hemangioblastoma (HB), 3 had primary central nervous system lymphomas, 1 had a glioblastoma, and 4 had single metastatic brain tumors (METs). Methionine-PET was performed on 9 patients except for 1 patient with a MET. The maximum standardized uptake value (SUVmax) of the tumor was measured and compared with pathologic findings.

Results

The SUVmax of FDG in HB was lower compared with that of other tumors (P = 0.001). On the other hand, the SUVmax of methionine in the HB cases was almost the same as that in other tumors (P = 0.07).

Conclusion

FDG-PET was helpful in differentiating HBs from adult cerebellar tumors.

Introduction

Primary intraaxial tumors are less common than extraaxial tumors in the adult posterior fossa. Hemangioblastoma (HB), which is the most common primary adult intraaxial posterior tumor,1 is easy to diagnose based on its typical appearance of an enhancing cystic nodule. However, solid HB is sometimes difficult to diagnose. Although conventional magnetic resonance imaging (MRI) is essential for diagnosis, it is not usually helpful in the differentiation of brain tumors. In such cases, positron emission tomography (PET) may offer useful complementary diagnostic information based on signals of tissue metabolic activity, which may differ among various tumor types. Both 18F-fluorodeoxyglucose (FDG)-PET and methionine PET are frequently used for the diagnosis of brain tumors.

To the best of our knowledge, there has only been 1 report that showed the PET findings of cerebellar HB, but this study did not assess the differentiation of HBs from other cerebellar tumors.2 The purpose of this study was to evaluate the usefulness of PET with FDG and methionine in differentiating HBs from adult primary intraaxial tumors and from a single cerebellar metastatic brain tumor (MET) in the posterior fossa.

Section snippets

Patients

This study included 8 patients with intraaxial cerebellar tumors (4 HBs, 3 primary central nervous system lymphomas, and 1 glioblastoma) and 4 patients with solitary METs who were treated at the Hokuto Hospital, Obihiro, Japan, between December 2009 and October 2017. All patients gave written informed consent before the study. In all patients, pathologic diagnosis was proven by surgery after PET. FDG-PET and methionine-PET were performed on the same day or the next day before surgery. None of

Results

The PET findings are shown in Table 1. The 2 cases of HB had relatively low mean SUVmax on FDG-PET (4.3) and methionine-PET (4.0) (Figure 1). The mean FDG-PET and methionine-PET SUVmax values were 15.5 and 5.1, respectively, in 3 cases of primary central nervous system lymphoma and 14.2 and 6.3, respectively, in 1 case of glioblastoma. The mean SUVmax of FDG-PET in the 4 cases of MET was 11.6, whereas that of methionine-PET in the 3 cases of MET was 5.0 (Figure 2). In the 4 cases of HB, the

Discussion

In the present study, we used FDG-PET and methionine-PET to differentiate HB from adult cerebellar primary intraaxial tumors and a single metastatic brain tumor. Our results revealed accumulation of FDG-PET and methionine-PET in these tumors, suggesting that FDG-PET may be useful for distinguishing cerebellar HB from other tumors.

HB is classified into 2 morphologic types: cystic and solid.3 HB can be easily diagnosed by its typical MRI findings, which is an enhancing cystic nodule. Because the

Conclusions

In contrast methionine, FDG uptake in HB was lower than that of other adult intraaxial cerebellar and metastatic brain tumors, suggesting that FDG-PET may be useful for distinguishing cerebellar HB from other tumors.

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Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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