Indium-111-pentetreotide imaging in intra-axial brain tumors: comparison with thallium-201 SPECT and MRI.
Highly undifferentiated glial tumors do not express somatostatin receptors (SSR) in contrast to low-grade astrocytomas which contain SSR. To differentiate a malignant glioma from a low-grade astrocytoma and to distinguish an SSR-positive intra-axial brain tumor from an SSR negative one, 111In-pentetreotide brain SPECT was prospectively undertaken.


METHODS
Eight patients with intra-axial brain tumors (three glioblastoma multiforme, one low-grade astrocytoma, one lymphoma, one medulloblastoma, one neurocytoma and one metastatic tumor) were studied. Thallium-201 and 111In-pentetreotide brain SPECT were performed with a 3- to 4-day interval before surgery. The SPECT findings were compared with those of Gd-enhanced MRI.


RESULTS
Increased uptake of 111In-pentetreotide was observed in all of the patients with glioblastoma multiforme (Grade in two and Grade + in one) despite lack of SSR. Low-grade astrocytoma exhibited minimal uptake of 111In-pentetreotide (Grade +). Remaining tumors had intense uptake of 111In-pentetreotide. Thallium-201 SPECT showed similar findings to those of 111In-pentetreotide scintigraphy except in two patients with glioblastoma multiforme: One with 201TL negative scan showed increased uptake of 111In-pentetreotide and the other showed increased thallium uptake but minimal uptake of 111In-pentetreotide. The uptake pattern of both 201Tl and 111In-pentetreotide appeared to correlate with Gd-enhanced MRI.


CONCLUSIONS
Indium-111-pentetreotide scintigraphy is sensitive in the detection of intra-axial brain tumors; however, it has no role in assessing the tumor grading and in the definition of the receptor profile.
Lee
J D
JD
Department of Diagnostic Radiology, Yonsei University, College of Medicine, Seoul, Korea.
Kim
D I
DI
Lee
J T
JT
Chang
J W
JW
Park
C Y
CY
D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000737:chemistry / Q000175:diagnosis / Q000000981:diagnostic imaging; D001932:Brain Neoplasms / Q000737:chemistry / Q000175:diagnosis / Q000000981:diagnostic imaging*; D002675:Child, Preschool; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D019786:Gadolinium DTPA; D005909:Glioblastoma / Q000737:chemistry / Q000175:diagnosis / Q000000981:diagnostic imaging; D006801:Humans; D007205:Indium Radioisotopes; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds; D004369:Pentetic Acid / Q000031:analogs & derivatives; D011446:Prospective Studies; D017481:Receptors, Somatostatin / Q000032:analysis; D012680:Sensitivity and Specificity; D013004:Somatostatin / Q000031:analogs & derivatives*; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D003287:Contrast Media; D007205:Indium Radioisotopes; D009942:Organometallic Compounds; D017481:Receptors, Somatostatin; D013794:Thallium Radioisotopes; D013004:Somatostatin; D004369:Pentetic Acid; C081788:pentetreotide; D019786:Gadolinium DTPA