ORIGINAL ARTICLE C-11 Choline Versus F-18 Fluorodeoxyglucose for Imaging Meningiomas An Initial Experience Giampiero Giovacchini, MD, PhD,* Federico Fallanca, MD,† Claudio Landoni, MD,*† Luigi Gianolli, MD,† Piero Picozzi, MD,‡ Luca Attuati, MD,‡ Mariarosa Terreni, MD,§ Maria Picchio, MD,† Cristina Messa, MD,*¶ and Ferruccio Fazio, MD*† Purpose: Positron emission tomography/computed tomography (PET/CT) with C-11 choline has been used for staging, restaging, and follow-up of various tumors, whereas its role for imaging meningiomas has only been preliminarily explored. The aim of this study was to compare C-11 choline and F-18 fluorodeoxyglucose (F-18 FDG) uptake in meningiomas and relate these findings to the histopathological analysis. Methods: Two sequential three-dimensional PET/CT scans with 370 MBq (10 mCi) of C-11 choline and 370 MBq (10 mCi) of F-18 FDG were performed 2 hours apart in 7 patients with histologically confirmed menin- giomas. Five patients had WHO grade I and 2 had WHO grade II meningi- oma. For each scan, two-dimensional regions of interest were drawn on tumor boundaries and on the contralateral side on CT images and copied to the corresponding PET images. SUV max and tumor-to-background ratio were calculated. Results: Relative to the contralateral side, C-11 choline uptake was in- creased in all meningiomas, whereas F-18 FDG uptake was decreased in 6 patients and increased in 1 of the 2 patients with grade II meningiomas. In the whole group, SUV max of C-11 choline and F-18 FDG were 3.6  1.3 and 5.7  1.3, respectively. The tumor-to-background ratio for C-11 choline was much higher than that for F-18 FDG (5.3  0.8 vs. 0.9  0.2, respectively) (P  0.001). The uptake of C-11 choline was higher in patients with grade II than in grade I meningiomas. Conclusions: These preliminary results suggest that C-11 choline may better image meningiomas in comparison with F-18 FDG. Clinical applications of C-11 choline PET/CT for grading and follow-up of meningiomas need to be assessed in further studies. Key Words: C-11 choline, meningiomas, PET/CT, F-18 FDG (Clin Nucl Med 2009;34: 7–10) M eningiomas are the most common nonglial primary brain tumors, accounting for approximately 14% to 20% of all brain tumors in adults. More than 90% of intracranial meningiomas are histopathologically benign and typically slow-growing. Surgical resection is the preferred treatment, whenever total removal can be accomplished with acceptable morbidity rates, with long-term con- trol rates of 33% to 60%. 1 Postoperative radiation therapy improves long-term local control and prevents tumor regrowth, especially after incomplete removal. 2 For evaluation before treatment, as well as during follow-up, computed tomography (CT) and magnetic resonance (MR) imaging might be complemented by functional imaging modalities, such as positron emission tomography (PET). F-18 fluorodeoxyglucose (F-18 FDG) was first used for im- aging meningiomas with PET. 3 Glucose metabolism correlated with tumor grade and was lower in nonrecurrent than recurrent meningi- omas. 3 However, because of the overlap in F-18 FDG uptake between meningiomas and normal brain cortex, more sensitive and specific tracers were developed. 4–9 C-11 choline was introduced for imaging various tumors, including prostate cancer, lung cancer, and brain tumor. 10 –14 The negligible uptake of the tracer in the normal brain allowed good delineation of brain tumor contours and diagnosis of tumor recur- rence. 12–14 However, the capacity of visualizing meningiomas with PET and C-11 choline was only preliminarily explored. 13,15 The aim of this study was to compare the capacity of C-11 choline and F-18 FDG for imaging meningiomas and relate these findings to the histopathological results. METHODS Patients Seven patients (5 women, 2 men; mean age: 63  10 years) with a diagnosis of meningioma based on CT and contrast-enhance- ment MR imaging were included in this study. The largest dimen- sion of the lesions ranged between 29 and 88 mm. A summary of the characteristics of the sample is reported in Table 1. All patients were studied with PET/CT, using C-11 choline and F-18 FDG on the same day as part of the presurgical evaluation. Within 1 week after the PET/CT scan, patients underwent surgery and histologic final diagnosis was obtained. Five patients had grade I meningioma, according to the World Health Organization (WHO) classification, whereas 2 had WHO grade II meningioma. Histologically, 3 grade I meningiomas were of the transitional type, 1 was fibrous, and 1 was meningothelial. Immunocytochemical evaluation of the prolif- eration index MIB-1 was obtained from paraffin-embedded tissue sections, according to standard procedures. 16 All grade I meningi- omas had MIB-1 lower than 1%, whereas in the 2 grade II menin- giomas, MIB-1 was 15% and 35%, respectively. Four patients also received stereotactic radiotherapy after surgery. PET/CT Methods PET/CT scans were acquired with the integrated PET/CT system Reveal-HD (CTI PET HR+, Siemens Emotion Dual Slice CT). Patients refrained from drinking and fasted for at least 6 hours before the intravenous administration of approximately 370 MBq (10 mCi) of C-11 choline. Patients were positioned supine in the scanner. A head-holder was used to maintain head position during scanning. Subsequently, a CT scout film was acquired to define the axial extension to be imaged. After acquisition of a helical CT scan, Received for publication November 20, 2007; revision accepted July 20, 2008. From the *Center for Molecular Bioimaging, University of Milano-Bicocca; Departments of †Nuclear Medicine, ‡Neurosurgery, and §Pathology, Scien- tific Institute San Raffaele, Milan; ¶Department of Nuclear Medicine, San Gerardo Hospital, Monza; and Institute for Bioimaging and Molecular Physiology, National Research Council, Milan, Italy. Reprints: Cristina Messa, MD, Department of Nuclear Medicine, San Gerardo Hospital, Monza, Italy. E-mail: c.messa@hsgerardo.org. Copyright © 2009 by Lippincott Williams & Wilkins ISSN: 0363-9762/09/3401-0007 Clinical Nuclear Medicine • Volume 34, Number 1, January 2009 7