title: Different thallium-201 single-photon emission tomographic patterns in benign and aggressive meningiomas.
abstract: To evaluate the possibility of preoperatively obtaining an index of aggressiveness for intracranial meningiomas, we prospectively studied 22 patients with computed tomographic or magnetic resonance imaging evidence of meningeal tumour, using single-photon emission tomography (SPET) of the brain and thallium-201 (201Tl). On a brain-dedicated SPET scanner, a rapid acquisition protocol with early, short scans was started simultaneously with the intravenous administration of 111 MBq 201Tl, covering the initial intratumoral distribution of the tracer. Twenty minutes post injection, a delayed SPET scan was also obtained. On the reconstructed and attenuation-corrected images we calculated the 201Tl concentration in tumour and normal contralateral brain tissue, and compared intratumoral tracer concentration in the initial and the final part of the rapid acquisition protocol. Benign and malignant meningiomas were classified as such based on histological examination. In malignant lesions, the ratio of the 201Tl concentration at 2-4 min post injection to that at 14-16 min was found to be significantly higher than in non-aggressive neoplasms (mean+/-1 SD: 1.14+/-0.31 and 0.56+/-0.13, respectively, P <0.01). Conversely, in the delayed scan, most lesions showed high tracer concentration, and the two groups could not be distinguished. In addition, three recurrent meningiomas displayed the same imaging behaviour as the malignant group, i.e. had similar 201Tl concentration values at 2-4 and at 14-16 min. Our findings suggest that the comparative assessment of intratumoral 201Tl concentration at 2-4 and at 14-16 min post injection could provide a fast, simple method to differentiate preoperatively intracranial meningiomas with different biological behaviour.
authors.affiliation: Dipartimento di Diagnostica per Immagini-Centro CNR per la Medicina Nucleare, Napoli, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Tedeschi
authors.forename: A
authors.initials: A
authors.lastname: Soricelli
authors.forename: A
authors.initials: A
authors.lastname: Brunetti
authors.forename: M
authors.initials: M
authors.lastname: Romano
authors.forename: A
authors.initials: A
authors.lastname: Bucciero
authors.forename: G
authors.initials: G
authors.lastname: Iaconetta
authors.forename: A
authors.initials: A
authors.lastname: Alfieri
authors.forename: A
authors.initials: A
authors.lastname: Postiglione
authors.forename: M
authors.initials: M
authors.lastname: Salvatore
mesh_terms: D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008577:Meningeal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008579:Meningioma / Q000000981:diagnostic imaging* / Q000473:pathology; D008875:Middle Aged; D015609:Organotechnetium Compounds; D010091:Oximes; D011446:Prospective Studies; D019690:Technetium Tc 99m Exametazime; D013794:Thallium Radioisotopes; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D015609:Organotechnetium Compounds; D010091:Oximes; D013794:Thallium Radioisotopes; D019690:Technetium Tc 99m Exametazime