Differential diagnosis in patients with ring-like thallium-201 uptake in brain SPECT.
This study was performed to investigate lesions with ring-like thallium-201 (201Tl) uptake and to determine whether SPECT provides any information in differential diagnosis.


METHODS
A total of 244 201Tl SPECT images were reviewed. In each study, early (15 min postinjection) and late (3 hr) brain SPECT images were obtained with 111 MBq of 201Tl. The early uptake ratio (ER; lesion to normal brain average count ratio) and the late uptake ratio (LR) and the L/E ratio (ratio of LR to ER) were calculated.


RESULTS
Ring-like uptake was observed in pre-therapeutic 26 SPECT images, including ten glioblastoma multiformes (ER, 3.45 +/- 0.64; LR, 2.74 +/- 0.54; L/E ratio 0.80 +/- 0.13), five meningiomas (6.48 +/- 2.34; 4.41 +/- 1.41; 0.72 +/- 0.19), four metastatic lung cancers (3.47 +/- 1.23; 2.40 +/- 0.98; 0.70 +/- 0.14), four brain abscesses (2.48 +/- 1.06; 1.59 +/- 0.30; 0.78 +/- 0.15), one invasive lesion of squamous cell carcinoma from the ethmoid sinus (1.54; 1.52; 0.99), one medulloblastoma (3.53; 3.52; 1.00) and one hematoma (3.32; 2.36; 0.71). The ER of meningioma was significantly higher than those of glioblastoma multiforme (p < 0.0005), metastatic lung cancer (p < 0.005) and brain abscess (p < 0.0005). There were no significant differences among these three entities. The LR of meningioma was significantly higher than those of glioblastoma multiforme (p < 0.005), metastatic lung cancer (p < 0.005) and brain abscess (p < 0.0001). The LR of brain abscess was significantly lower than that of glioblastoma multiforme (p < 0.05). The L/E ratio could not differentiate these four entities.


CONCLUSIONS
High ER and high LR in a lesion with ring-like uptake is likely an indicator of meningioma. The LR of brain abscess was significantly lower than that of glioblastoma multiforme, but 201T1 SPECT has still difficulty in differentiating abscess from brain tumor.
Kinuya
Keiko
K
Department of Nuclear Medicine, Tonami General Hospital, Toyama, Japan. dinky@d9.dion.ne.jp
Ohashi
Masahiro
M
Itoh
Syotaro
S
Yamamoto
Kenji
K
Sakai
Sotaro
S
Kakuda
Kiyoshi
K
Nobata
Koji
K
Kato
Naoko
N
Terahara
Shintaro
S
Taki
Suzuka
S
D000328:Adult; D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging*; D001922:Brain Abscess / Q000175:diagnosis / Q000000981:diagnostic imaging*; D001932:Brain Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000556:secondary; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis; D003937:Diagnosis, Differential; D005005:Ethmoid Sinus / Q000000981:diagnostic imaging; D005260:Female; D005909:Glioblastoma / Q000175:diagnosis / Q000556:secondary; D006406:Hematoma / Q000000981:diagnostic imaging; D006801:Humans; D020300:Intracranial Hemorrhages / Q000000981:diagnostic imaging; D008175:Lung Neoplasms / Q000473:pathology / Q000556:secondary; D008297:Male; D008527:Medulloblastoma / Q000175:diagnosis / Q000556:secondary; D008579:Meningioma / Q000175:diagnosis / Q000556:secondary; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009380:Neoplasms, Nerve Tissue / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000556:secondary; D010255:Paranasal Sinus Neoplasms / Q000175:diagnosis; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D013793:Thallium; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D019275:Radiopharmaceuticals; C027549:thallium chloride; D013793:Thallium