[Differential diagnosis between recurrence of brain tumor and radiation necrosis by 201Tl SPECT].
In order to differentiate recurrence of brain tumor from radiation necrosis, we performed 201Tl brain SPECT in 16 post-operative patients. Five of them had residual anaplastic astrocytoma. Final diagnosis of the other 11 patients was recurrent astrocytoma (n = 6), cerebral radiation necrosis (n = 5), based on re-operation (n = 9) and more than one year follow-up finding (n = 2). Early and delayed images were obtained at 10-15 min. and 4 hrs. after i.v. injection of 111 MBq of 201Tl chloride. Counts ratio of a lesion to the normal brain (L/N) was calculated by creating rectangular ROI over each area. All of the patients with recurrent or residual tumor showed L/N ratios of more than 2.5 on the early images (mean 4.70 +/- 2.65). On the other hand, L/N ratios on the early images were less than 2.5 in patients with radiation necrosis (mean 2.05 +/- 0.25, p less than 0.001). In conclusion, a quantitative assessment using 201Tl brain SPECT may be useful in differentiating recurrence of brain tumor from radiation necrosis.
Kosuda
S
S
Department of Radiology, Tokyo Metropolitan Komagome Hospital.
Shioyama
Y
Y
Kamata
N
N
Suzuki
K
K
Tanaka
Y
Y
Nakamura
O
O
Matsutani
M
M
D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000000981:diagnostic imaging; D001921:Brain / Q000473:pathology / Q000528:radiation effects; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D009364:Neoplasm Recurrence, Local; D011832:Radiation Injuries / Q000000981:diagnostic imaging* / Q000209:etiology; D011878:Radiotherapy / Q000009:adverse effects*; D015899:Tomography, Emission-Computed, Single-Photon