Analysis of perfusion weighted image of CNS lymphoma

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Abstract

Purpose

It is difficult to differentiate CNS lymphoma from other tumors such as malignant gliomas, metastases, or meningiomas with conventional MR imaging, because the imaging findings are overlapped between these tumors. The purpose of this study is to investigate the perfusion weighted MR imaging findings of CNS lymphomas and to compare the relative cerebral blood volume ratios between CNS lymphomas and other tumors such as high grade gliomas, metastases, or meningiomas.

Materials and methods

We retrospectively reviewed MRI findings and clinical records in 13 patients with pathologically proven CNS lymphoma between January 2006 and November 2008. We evaluated the relative cerebral blood volume ratios of tumor, which were obtained by dividing the values obtained from the normal white matter on MRI.

Results

Total 13 patients (M:F = 8:5; age range 46–67 years, mean age 52.3 years) were included. The CNS lymphomas showed relatively low values of maximum relative CBV ratio in most patients regardless of primary or secondary CNS lymphoma.

Conclusion

Perfusion weighted image may be helpful in the diagnosis of CNS lymphoma in spite of primary or secondary or B cell or T cell.

Introduction

Primary central nervous system (CNS) lymphoma is a rare malignant CNS tumor and its incidence increased in the past three decades [1]. The radiological findings of primary cerebral lymphomas were previously described in many reports with conventional MR imaging techniques such as T1 weighted image (WI) and T2-WI [2], [3], [4], [5], [6], [7], [8]. Most lymphomas show hypo- or iso-signal intensity (SI) on T1-WI, variable SI on T2-WI and strong enhancement. The MR imaging findings of cerebral lymphomas are variable and overlap with conventional MR imaging findings of other intracranial tumors such as high grade gliomas, metastases or meningiomas. Therefore, the correct diagnosis of CNS lymphoma is not easy on conventional MRI and various methods such as perfusion weighted image, diffusion tensor imaging, MR spectroscopy, and fluorodeoxyglucose-positron-emission tomography (FDG-PET) were used [6], [9], [10], [11], [12], [13]. Among them, perfusion MR imaging with relative cerebral blood volume (rCBV) ratio has made an important role in the diagnosis of cerebral lymphomas [14], [15]. Sugahara et al. reported that cerebral lymphomas had a tendency to have low rCBV values in 1999 [14]. Hakyemez et al. reported that the rCBV ratios of high grade gliomas were higher than those of lymphomas in 2006 [15]. However, previous studies included generally a small number of cerebral lymphoma patients. So the purpose of this study is to investigate the perfusion MR imaging findings in a relatively large series of cerebral lymphoma patients and to compare the rCBV ratios between CNS lymphomas and other tumors such as high grade gliomas, metastases, or meningiomas.

Section snippets

Materials and methods

Total 51 patients were pathologically confirmed as CNS lymphoma between January 2006 and November 2008. Among them, 13 patients with preoperative perfusion weighted MR imaging were included in this study. We retrospectively reviewed imaging findings and medical records in 13 patients (M:F = 8:5; age range 46–67 years, mean age 52.3 years) with CNS lymphoma. 12 patients had diffuse large B cell lymphoma (DLBL) and the other one patient had peripheral T cell lymphoma (PTL). 11 of 13 patients had

Results

The maximum relative CBV ratio in all patients was summarized in Table 1.

All CNS lymphomas showed strong enhancement of solid component regardless of primary or secondary or B cell or T cell after gadolinium administration.

The maximum relative CBV ratio was ranged from 0.67 to 2.67 (mean: 1.68 ± 0.71). The maximum relative CBV ratios of primary and secondary cerebral lymphomas was ranged from 0.67 to 2.67 (mean: 1.65 ± 0.76) and ranged from 1.66 to 2.06 (mean: 1.86 ± 0.28), respectively (Fig. 1, Fig.

Discussion

Primary CNS lymphoma is a rare, but aggressive neoplasm with increased incidence in immunocompetent as well as immunocompromised patients [7], [8], [16].

In spite of several characteristic imaging finding on conventional MRI, it is difficult that the correct diagnosis of CNS lymphoma is difficult in the intracranial mass lesions. However, the correct diagnosis of CNS lymphoma is important, because the prognosis and treatment of CNS lymphoma are different from high grade gliomas, metastases, or

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