Magnetic resonance investigation of bone marrow following priming and stem cell mobilization

3-Tesla MR spectroscopy in patients subjected to bone marrow transplantation: clinical correlations

PURPOSE

This study evaluated the usefulness of 3-Tesla magnetic resonance (MR) spectroscopy in patients with non-Hodgkin's lymphoma (NHL) undergoing bone marrow transplantation (BMT).

MATERIALS AND METHODS

Twelve NHL patients who were candidates for BMT underwent three MR examinations of the lumbosacral spine: before ablative therapy for BMT, 15±4 days and 54±24 days after BMT. The MR study was supplemented by spectroscopic analysis. The lipid content was calculated and expressed as a percentage of lipid signal intensity relative to total signal intensity [fat fraction (FF)].

RESULTS

In the first MR study, the FF was 62.5±7%, in the second it was 70.75±5% and in the third it was 75±1%. We observed a statistically significant difference between FF values calculated at the various MR studies (p=0.02) and between red blood cell count (p=0.017), platelet count (p=0.003) and haematocrit (p<0.001) at the three MR studies. FF had a statistically significant correlation with the number of circulating platelets (p<0.01)

CONCLUSIONS

MR spectroscopy of the bone marrow of NHL patients undergoing BMT is noninvasive and highly sensitive for characterising and monitoring bone marrow after BMT.

Pharmacokinetic modeling of dynamic contrast-enhanced MRI of the hand and wrist in rheumatoid arthritis and the response to anti-tumor necrosis factor-α therapy

Dynamic contrast-enhanced MRI (DCE-MRI) of the hand and wrist was performed in 11 patients with rheumatoid arthritis twice before and once 2 weeks after treatment with anti-tumor necrosis factor (TNF)-alpha therapy. A rapid, T1-weighted 3D spoiled gradient echo (SPGR) sequence was used for the dynamic imaging. T1 estimation was performed using similar images obtained at different flip angles. The relative radiofrequency field was estimated from the known T1 of the periarticular fatty marrow. The arterial input function (AIF) was measured at each examination, and normalized to the expected plasma concentration to reduce partial volume effects. Synovial enhancement was modeled to yield values for Ktrans, ve, and vp. Ktrans and ve showed good reproducibility. There was a significant decrease of about 20% in Ktrans after 2 weeks of treatment. This study demonstrates the potential of DCE-MRI and pharmacokinetic modeling to study early changes in inflammatory activity in rheumatoid arthritis following treatment.