Nuclear magnetic resonance imaging of bone marrow in childhood leukaemia

[Aseptic femur head osteonecrosis during treatment of acute lymphoblastic leukemia in the child]

Avascular femoral head necrosis (AFN) is an uncommon complication of acute lymphoblastic leukemia (ALL) occurring in association with serious functional late effects. One of the many risk factors is high-dose corticosteroid therapy.

CASE REPORT

Three children belonging to a series of 266 patients developed AFN. The diagnosis was not made immediately when X-rays were normal. In spite of the fact that treatment was begun as soon as possible, the three children had a difference in the length of their legs, with reduction of their walking perimeter and, in one case, an arthroplasty was necessary.

CONCLUSION

If some patients treated for ALL limp or suffer when walking or when practising sports, the diagnosis of AFN is to be evoked. The diagnosis is not only based on simple X-rays but also on magnetic resonance imaging, which is more sensitive and reveals lesions earlier. The treatment consists of immobilization of the hip, whether or not associated with surgical procedures.

Bone marrow changes on MRI in children with acute lymphoblastic leukaemia 5 years after treatment

T1-weighted magnetic resonance imaging (MRI) of the lower extremities was performed 5 years after the cessation of therapy on 25 children treated for acute lymphoblastic leukaemia (ALL). Signal intensity pathologies considered to be related with the leukaemia itself or the treatment of ALL were found in nine of 25 children (36%). Two of these children had findings of osteonecrosis, five had a patchy signal pattern, one had diffuse inhomogeneity of the bone marrow signal intensity in complete remission and one had diffusely decreased signal intensity preceding the diagnosis of relapse. MRI unexpectedly revealed many bone marrow pathologies in symptomless children successfully treated for ALL. Especially, osteonecrosis might cause significant disability, and the aetiology, clinical course and prognosis of this complication are not well known. The intensive dexamethasone medication included in the treatment protocols may be responsible for the development of osteonecrosis. However, the prognosis of osteonecrosis in the long run requires further studies.

Osteonecrosis in children treated for acute lymphoblastic leukemia: a magnetic resonance imaging study after treatment

The purpose of the study was to find out the prevalence of osteonecrosis in children with acute lymphoblastic leukemia (ALL) in complete bone marrow remission at the end of the treatment. Twenty-eight children with ALL underwent MRI of the upper and/or lower extremities. Bone marrow signal intensity was analyzed on T1-weighted images, where circumscribed lesions with a rim of low signal intensity were considered typical of osteonecrosis. Osteonecrosis was found in 9 of the 28 children (32%, 95% CI 16% to 52%). Five of them were asymptomatic. They had been treated with high risk and intermediate risk protocols, both of which include a delayed intensification phase with dexamethasone. None of the patients with standard risk ALL were found to have developed osteonecrosis. Osteonecroses occurred unexpectedly in symptomless patients and in patients with mild transient symptoms treated with high risk and intermediate risk protocols. Our study suggests that the intensification phase of the treatment protocols with intensive dexamethasone medication might be responsible for the development of osteonecrosis.

Imaging the bone marrow with magnetic resonance during a crisis and in chronic forms of sickle cell disease

Five patients with sickle cell disease have been studied by magnetic resonance imaging (MRI) in three instances during a crisis. Attention was directed to the pelvis and lower extremities. Bone marrow pathology has been classified according to generalised or circumscribed alterations in signal intensity on T1 weighted spin-echo sequences. Both acute and chronic changes were observed.