Proton MR imaging and spectroscopy evaluation of aplastic anemia: three bone marrow patterns.

PURPOSE

The purpose of this study was to classify bone marrow intensity patterns in aplastic anemia with proton MRI and to compare them with MR spectroscopic findings quantitatively and qualitatively.

METHOD

Twelve patients with aplastic anemia and six normal volunteers were examined with a 1.5 T MR unit. T1-weighted SE, fast STIR, and opposed-phase T1-weighted RF-spoiled GE images (op-SPGR) were acquired with MR images, while MR spectroscopy was performed with a stimulated echo acquisition mode without water suppression.

RESULTS

Three bone marrow patterns were determined in aplastic anemia with MR images: marrow a with low intensity on fast STIR and high intensity on T1-weighted imaging and op-SPGR, marrow b with low intensity on T1-weighted imaging and op-SPGR and high intensity on fast STIR, and marrow c with low intensity on T1-weighted imaging and high intensity on fast STIR and op-SPGR. MR spectroscopy quantitatively showed that the ratio of water to fat of marrow a significantly decreased (mean 0.41) and that of marrow c increased (mean 3.40) compared with those of marrow b (mean 1.09) and normal bone marrow (mean 1.04). There were no differences of the types of fat signals between aplastic anemia and normal bone marrow with MR spectroscopy.

CONCLUSION

MR imaging and spectroscopy were noninvasive methods of classifying bone marrow patterns and quantifying bone marrow content in aplastic anemia, which may improve the results currently obtained with biopsy.