Magnetic resonance imaging of femoral marrow cellularity in hypocellular haemopoietic disorders.

AIM: Magnetic resonance imaging (MRI) of the femora was used to investigate the marrow cellularity during the evolution of non-transplanted aplastic anaemia (AA) and hypocellular myelodysplastic syndrome (h-MDS) in order to investigate the relationship between this cellularity and disease progression.

METHODS

Magnetic resonance imaging was performed in adult patients with pancytopaenia and hypocellular bone marrow. Coronal T1 weighted and STIR images were obtained, and analysed semiquantitatively. These data were compared with diagnosis, peripheral blood counts and bone marrow histology at diagnosis and at the time of the MRI examination.

RESULTS

Patients were examined 2-84 months after diagnosis (median, 16 months). In AA, 11/13 patients showed a fatty, faint or nodular pattern. In h-MDS, the majority of the patients (10/14) had a scattered or uniform signal pattern. In AA, a significant correlation was found between the degree of femoral cellularity and disease duration. Only three cases had diffuse high signal on STIR: among them, one had paroxysmal nocturnal haemoglobinuria and the other developed acute leukaemia 3 months after MRI examination. Four patients have died: three with h-MDS presenting a scattered (two cases) or a uniform (one case) MRI signal and one with AA (with a nodular pattern)

CONCLUSION

In AA, femoral haemopoiesis is usually not pronounced, and if present, does not contribute to the improvement of blood counts. In h-MDS, patients with discrete femoral haemopoiesis had an improvement in their blood counts with disease duration, similar to that found in AA. Conversely, in patients with pronounced femoral cellularity, blood counts remained stable or had deteriorated since diagnosis. This favours the hypothesis that, as is observed in MDS with a hypercellular marrow, scattered or uniform marrow patterns in femoral MRI are signs of more aggressive disease.