MAGNETIC RESONANCE IMAGING (MRI) AND MAGNETIC RESONANCE SPECTROSCOPY (MRS) OF INTRACRANIAL LIPOMAS

R. Fründ, A. Geissler, M. Gliese, J. Seitz, S. Feuerbach

Rüdiger Fründ Institut für Röntgendiagnostik Klinikum der Universität Regensburg, D-93042 Regensburg Germany

Received 6/3/97 Accepted 9/16/97

2. INTRODUCTION

The intracranial lipoma is a rare benign neoplasm. In an autopsy study, lipomas accounted for only 0.08 % of all brain tumors (1). Another study yielded a value of 0.1 % (2). With the introduction of computed tomography (CT), the incidence of this often symptom-free tumor increased. In a study of Kazner et al. (3) including 17,500 cranial CT scans, the incidence for intracranial lipomas was 0.06 % for all CT scans and 0.34% of all intracranial tumors. The widespread use of the magnetic resonance imaging (MRI) will probably further increase the incidence.

Intracranial lipomas are midline tumors. Even though the etiology of lipomas is still unknown (4), they are congenital malformations, sometimes even called lipomatous hamartomas (5). They possibly originate from meninx primitiva (6). Pericallosa lipomas are often associated with other developmental malformations such as partial or complete agenesis of corpus callosum (7).

Fatty tissue can be easily identified with MRI if sequences with fat suppression are used. Magnetic resonance spectroscopy (MRS) allows even more specific identification of fatty tissue especially lipids. MRS offers insights on the structure of lipids present in lipomas, malignant tumors and normal fat and allows detection of structural differences.