Perfusion MRI and SPECT of brain after treatment for childhood acute lymphoblastic leukemia.
BACKGROUND
Treatment of childhood leukemia may cause perfusion defects in the brain observed by SPECT. Perfusion MRI is a novel method to study brain perfusion which has not been used previously in this setting. This study was performed to compare SPECT with perfusion MRI in patients with acute lymphoblastic leukemia (ALL) after treatment.


METHODS
Nineteen children or young adults underwent perfusion MRI at the cessation of treatment (n = 9) or 4-8 years after the treatment (n = 10). Seventeen of them also underwent SPECT at the time of MRI (within 0-3 days, n = 14) or a couple of months later (1.5-6 months, n = 3). SPECT images and relative cerebral blood volume (CBV) and cerebral blood flow (CBF) maps from perfusion MRI were analyzed visually. Relative CBV ratios of gray matter to white matter and thalamus to white matter were also calculated from the perfusion MRI.


RESULTS
Perfusion MRI did not show any focal perfusion defects, while small defects were observed by SPECT in five of 17 children (29%) in the basal, frontal or temporal areas on the left. No significant differences were observed by perfusion MRI in the relative CBV ratios in the different treatment groups. Time since treatment, age at diagnosis, brain irradiation, or findings in conventional MRI or SPECT did not have any effect on the relative perfusion values either.


CONCLUSIONS
SPECT may show small perfusion defects after treatment for childhood leukemia which are not visible by perfusion MRI. The clinical significance or prognosis of these defects is not known.
Pääkkö
Eija
E
Department of Diagnostic Radiology, University of Oulu, Kajaanintie 50, 90220 Oulu, Finland. eija.paakko@oulu.fi
Lehtinen
Satu
S
Harila-Saari
Arja
A
Ahonen
Aapo
A
Jauhiainen
Jukka
J
Torniainen
Pentti
P
Pyhtinen
Juhani
J
Lanning
Marjatta
M
D000293:Adolescent; D000328:Adult; D001921:Brain / Q000098:blood supply*; D002560:Cerebrovascular Circulation; D002561:Cerebrovascular Disorders / Q000139:chemically induced / Q000175:diagnosis* / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D003561:Cytarabine / Q000009:adverse effects / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007049:Iatrogenic Disease; D008279:Magnetic Resonance Imaging; D008297:Male; D008727:Methotrexate / Q000009:adverse effects / Q000627:therapeutic use; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy*; D019690:Technetium Tc 99m Exametazime; D015899:Tomography, Emission-Computed, Single-Photon; D014750:Vincristine / Q000009:adverse effects / Q000627:therapeutic use
D003561:Cytarabine; D019690:Technetium Tc 99m Exametazime; D014750:Vincristine; D008727:Methotrexate