HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH RSS TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Henze, M. Articles by Haberkorn, U. Search for Related Content PubMed PubMed Citation Articles by Henze, M. Articles by Haberkorn, U.

PET and SPECT for Detection of Tumor Progression in Irradiated Low-Grade Astrocytoma: A Receiver-Operating-Characteristic Analysis

¹ Department of Nuclear Medicine, University of Heidelberg, Heidelberg, Germany
² Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center, Heidelberg, Germany
³ Department of Diagnostic Radiology, Eberhard-Karls University, Tübingen, Germany
⁴ Department of Radiation Oncology, University of Heidelberg, Heidelberg, Germany
⁵ Division of Radiochemistry and Radiopharmacology, German Cancer Research Center, Heidelberg, Germany

Differentiation between tumor progression and radiation necrosis is one of the most difficult tasks in oncologic neuroradiology. Functional imaging of tumor metabolism can help with this task, but the choice of tracer is still controversial. This prospective study following up irradiated low-grade astrocytoma (LGA) was, to our knowledge, the first receiver-operating-characteristic (ROC) analysis that intraindividually evaluated the diagnostic performance of the SPECT tracers 3-[¹²³I]iodo--methyl-L-tyrosine (IMT) and ^99mTc(I)-hexakis(2-methoxyisobutylisonitrile) (MIBI) and the PET tracer ¹⁸F-FDG. Methods: We examined 17 patients, initially with histologically proven LGA and treated by stereotactic radiotherapy, who presented with new gadolinium-diethylenetriaminepentaacetic acid–enhancing lesions (n = 26) on MRI. At that time, MRI could not differentiate between progressive tumor and nonprogressive tumor. This MRI examination was closely followed by ¹⁸F-FDG PET and by ^99mTc-MIBI and ¹²³I-IMT SPECT. Lesions were classified as progressive tumor (n = 17) or nonprogressive tumor (n = 9) on the basis of prospective follow-up (through clinical examination, MRI, and proton MR spectroscopy) for 26.6 ± 6.6 mo after PET or SPECT. Results: ¹²³I-IMT yielded the best ROC characteristics and was the most accurate for classification, with an area under the ROC curve (A_z) of 0.991. The A_z of ¹⁸F-FDG (0.947) was not significantly lower than that of ¹²³I-IMT. The difference in the A_z of ^99mTc-MIBI (0.713) from the A_z of the other tracers used in our study was highly significant (P 0.01). ^99mTc-MIBI SPECT was of low accuracy and, especially, of poor sensitivity even at modest specificity values. Conclusion: ¹²³I-IMT SPECT imaging of amino acid transport accurately detects tumor progression in patients with irradiated LGA. In contrast to ¹²³I-IMT, ¹⁸F-FDG PET was slightly less accurate for classification, and ^99mTc-MIBI SPECT was of limited value. Imaging of amino acid transport with ¹²³I-IMT is a valuable additional tool for the follow-up of LGA, allowing early, noninvasive differentiation of lesions with ambiguous morphology after irradiation.

Key Words: ¹⁸F-FDG • 3-¹²³I-iodo--methyl-L-tyrosine • ^99mTc(I)-hexakis(2-methoxyisobutylisonitrile) • radiotherapy • astrocytoma

This article has been cited by other articles:

				W. Chen Clinical Applications of PET in Brain Tumors J. Nucl. Med., September 1, 2007; 48(9): 1468 - 1481. [Abstract] [Full Text] [PDF]

				M. E. Mullins, G. D. Barest, P. W. Schaefer, F. H. Hochberg, R. G. Gonzalez, and M. H. Lev Radiation Necrosis Versus Glioma Recurrence: Conventional MR Imaging Clues to Diagnosis AJNR Am. J. Neuroradiol., September 1, 2005; 26(8): 1967 - 1972. [Abstract] [Full Text] [PDF]