title: Perfusion and diffusion MRI combined with ¹¹C-methionine PET in the preoperative evaluation of suspected adult low-grade gliomas.
abstract: Perfusion and diffusion magnetic resonance imaging (pMRI, dMRI) are valuable diagnostic tools for assessing brain tumors in the clinical setting. The aim of this study was to determine the correlation of pMRI and dMRI with ¹¹C-methionine positron emission tomography (MET PET) in suspected low-grade gliomas (LGG) prior to surgery. Twenty-four adults with suspected LGG were enrolled in an observational study and examined by MET PET, pMRI and dMRI. Histological tumor diagnosis was confirmed in 23/24 patients (18 gliomas grade II, 5 gliomas grade III). The maximum relative cerebral blood volume (rCBV(max)) and the minimum mean diffusivity (MD(min)) were measured in tumor areas with highest MET uptake (hotspot) on PET by using automated co-registration of MRI and PET scans. A clearly defined hotspot on PET was present in all 23 tumors. Regions with rCBV(max) corresponded with hotspot regions in all tumors, regions with MD(min) corresponded with hotspot regions in 20/23 tumors. The correlation between rCBV(max) (r = 0.19, P = 0.38) and MD(min) (r = -0.41, P = 0.053) with MET uptake in the hotspot was not statistically significant. Taken into account the difficulties of measuring perfusion abnormalities in non-enhancing gliomas, this study demonstrates that co-registered MET PET and pMRI facilitates the identification of regions with rCBV(max). Furthermore, the lack of a clear positive correlation between tumor metabolism in terms of MET uptake and tumor vascularity measured as rCBV(max) suggests that combined pMRI/PET provides complementary baseline imaging data in these tumors.
authors.affiliation: Department of Neuroscience, Neurology, Uppsala University, University Hospital, Sweden.
authors.forename: Shala Ghaderi
authors.initials: SG
authors.lastname: Berntsson
authors.forename: Anna
authors.initials: A
authors.lastname: Falk
authors.forename: Irina
authors.initials: I
authors.lastname: Savitcheva
authors.forename: Andrea
authors.initials: A
authors.lastname: Godau
authors.forename: Maria
authors.initials: M
authors.lastname: Zetterling
authors.forename: Göran
authors.initials: G
authors.lastname: Hesselager
authors.forename: Irina
authors.initials: I
authors.lastname: Alafuzoff
authors.forename: Elna-Marie
authors.initials: EM
authors.lastname: Larsson
authors.forename: Anja
authors.initials: A
authors.lastname: Smits
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D002250:Carbon Radioisotopes; D002560:Cerebrovascular Circulation; D005260:Female; D005910:Glioma / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008715:Methionine; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D060787:Neoplasm Grading; D010363:Pattern Recognition, Automated; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D055815:Young Adult
chemical_list: D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; D008715:Methionine