Magnetic resonance imaging of normal meningeal enhancement at 1.5 T

Rationale and Objectives. We examined patterns of intracranial meningeal enhancement on gadolinium chelate contrast media-enhanced 1.5-T spin-echo magnetic resonance (MR) imaging and developed criteria that might be useful for distinguishing between normal and abnormal meningeal enhancement. Methods. The convexity, fair cerebri, tentorium cerebelli, and suprasellar cistern regions of 204 patients were prospectively evaluated for contrast enhancement with a grading system ranging from 0 (no enhancement) to 5 (diffuse, irregular, thickened enhancement). Meningeal findings were correlated with other MR abnormalities and pertinent clinical histories that have been associated previously with meningeal enhancement. Results. Short-segment convexity meningeal enhancement was commonly seen and most likely represents intravascular contrast material in normal meningeal vessels. Such enhancement did not correlate with the presence of other MR abnormalities. Long-segment (>3 cm) or diffuse convexity meningeal enhancement did correlate with other significant MR abnormalities and pertinent clinical history, Fine linear falcine and tentorial meningeal enhancement, as an isolated finding, did not correlate with other MR or clinical abnormalities. The suprasellar cistern and ventricular walls were rarely enhanced. Conclusion. Short-segment convexity meningeal contrast enhancement is a normal finding representing normal vascular structures. More extensive convexity meningeal enhancement is abnormal and should prompt careful examination of the remainder of an MR image as well as the patient's clinical history for an etiology of the enhancement.