Noninvasive grading of untreated gliomas: a comparative study of MR imaging and 3-(iodine 123)-L-alpha-methyltyrosine SPECT.
OBJECTIVE
To compare the accuracy of magnetic resonance (MR) imaging scores with that of 3-(iodine 123)-L-alpha-methyltyrosine ((123)I-IMT) single photon emission computed tomography (SPECT) in the noninvasive grading of untreated gliomas.


METHODS
The study comprised 15 patients with low-grade gliomas (grades I-II, according to World Health Organization criteria) and 33 patients with high-grade gliomas (grades III-IV). The lesions were evaluated by using an MR imaging score based on nine criteria. The (123)I-IMT uptake was quantified as the ratio between the amino acid uptake in the tumor and that in the contralateral hemisphere. To test for potentially significant differences in diagnostic performance between contrast material-enhanced MR imaging and (123)I-IMT SPECT, binormal receiver operating characteristic curves were fitted to the data and compared by using the area test.


RESULTS
The accuracy of MR imaging in the noninvasive grading of untreated gliomas was higher than that of (123)I-IMT SPECT (88% vs 79%). However, the difference in diagnostic performance was not significant on the basis of findings at receiver operating characteristic analysis (P >.2). Neither MR imaging nor (123)I-IMT SPECT allowed differentiation between high-grade gliomas (grades III and IV).


CONCLUSIONS
Although (123)I-IMT uptake is significantly higher in high-grade gliomas than in low-grade gliomas, the performance of (123)I-IMT SPECT adds little to the accuracy of determining tumor grade when MR imaging is performed.
Riemann
Burkhard
B
Department of Nuclear Medicine, University of Münster, Albert-Schweitzer-Strasse 33, 48129 Münster, Germany. riemanb@uni-muenster.de
Papke
Karsten
K
Hoess
Norbert
N
Kuwert
Torsten
T
Weckesser
Matthias
M
Matheja
Peter
P
Wassmann
Hansdetlef
H
Heindel
Walter
W
Schober
Otmar
O
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001254:Astrocytoma / Q000175:diagnosis / Q000473:pathology; D001706:Biopsy; D001921:Brain / Q000473:pathology; D001932:Brain Neoplasms / Q000145:classification / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D005909:Glioblastoma / Q000175:diagnosis / Q000473:pathology; D005910:Glioma / Q000145:classification / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon; D019805:alpha-Methyltyrosine / Q000493:pharmacokinetics
D007457:Iodine Radioisotopes; D019805:alpha-Methyltyrosine