MR imaging of the normal meninges: comparison of contrast-enhancement patterns on 3D gradient-echo and spin-echo images.

OBJECTIVE

The purpose of this study was to determine the enhancement pattern of the normal meninges on T1-weighted three-dimensional Fourier transform gradient-echo (3DGE) MR images and to compare this pattern with that observed on conventional two-dimensional Fourier transform spin-echo (2DSE) images. This will serve as a basis for comparison when cases of suspected meningeal pathology are evaluated.

SUBJECTS AND METHODS

The appearance of the normal meninges after administration of gadopentetate dimeglumine was evaluated on 2DSE and 3DGE images in 69 patients who had no known or suspected meningeal abnormality. The total percentage of meningeal surface area that underwent contrast enhancement and the continuity of meningeal enhancement were evaluated at four anatomic levels.

RESULTS

In most patients, 2DSE images showed short segments (i.e., < 3 cm) of meningeal enhancement, with enhancement of less than 50% of total meningeal surface area. However, enhancement of 76-100% of total meningeal surface area was routinely observed on 3DGE images, with long segments (i.e., > 3 cm) or continuous patterns most frequently observed. The differences between 2DSE and 3DGE sequences were statistically significant for all regions that were assessed.

CONCLUSION

Continuous meningeal enhancement or enhancement of long segments of normal meninges is routinely observed on contrast-enhanced 3DGE images; this appearance differs from those of enhanced 2DSE images and should not be interpreted as abnormal.