MAGNETIC-RESONANCE-IMAGING OF NORMAL MENINGEAL ENHANCEMENT AT 1.5 T

Rationale and Objectives. We examined patterns of intracranial meninge al enhancement on gadolinium chelate contrast media-enhanced 1.5-T spi n-echo magnetic resonance (MR) imaging and developed criteria that mig ht 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 e valuated for contrast enhancement with a grading system ranging from 0 (no enhancement) to 5 (diffuse, irregular, thickened enhancement). Me ningeal findings were correlated with other MR abnormalities and perti nent clinical histories that have been associated previously with meni ngeal enhancement. Results. Short-segment convexity meningeal enhancem ent was commonly seen and most likely represents intravascular contras t material in normal meningeal vessels. Such enhancement did not corre late with the presence of other MR abnormalities. Long-segment (>3 cm) or diffuse convexity meningeal enhancement did correlate with other s ignificant MR abnormalities and pertinent clinical history, Fine linea r falcine and tentorial meningeal enhancement, as an isolated finding, did not correlate with other MR or clinical abnormalities. The supras ellar cistern and ventricular walls were rarely enhanced. Conclusion. Short-segment convexity meningeal contrast enhancement is a normal fin ding representing normal vascular structures. More extensive convexity meningeal enhancement is abnormal and should prompt careful examinati on of the remainder of an MR image as well as the patient's clinical h istory for an etiology of the enhancement.