Correlation of diffusion tensor, dynamic susceptibility contrast MRI and 99mTc-Tetrofosmin brain SPECT with tumour grade and Ki-67 immunohistochemistry in glioma

Abstract

ObjectiveAssessment of the grade and type of glioma is of paramount importance for prognosis. Tumour proliferative potentials may provide additional information on the behaviour of the tumour, its response to treatment and prognosis. The purpose of this study was to investigate the correlation between diffusion tensor imaging (DTI), dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) and 99mTc-Tetrofosmin brain single-photon emission computed tomography (SPECT), and the tumour grade and Ki-67 labelling index in newly diagnosed gliomas. MethodsStudy was made of patients with suspected glioma on brain MRI between December 2010 and January 2012, by DTI, DSC MRI and 99mTc-Tetrofosmin brain SPECT. The proliferative activity of each tumour was measured by deriving the Ki-67 proliferation index from immunohistochemical staining of tumour specimens. ResultsGlioma was newly diagnosed in 25 patients (17 men, 8 women, aged 19–79 years, median 55 years). The Ki-67 index ranged from 1% to 80% (mean 19.4%). On evaluation of the relationship between the 99mTc-Tetrofosmin tumour uptake by gliomas was found to be significantly correlated with cellular proliferation (rho=0.924, p<0.0001). Regarding DTI, significant negative correlation was demonstrated between the apparent diffusion coefficient (ADC) ratio and the Ki-67 index (rho=−0.545, p=0.0087). Significant correlation was also observed between the fractional anisotropy (FA) ratio and the Ki-67 index (rho=0.489, p=0.02). Strong correlation was found between relative cerebral blood volume (rCBV) and Ki-67 index (rho=0.853, p<0.0001), and between the 99mTc-Tetrofosmin lesion-to-normal (L/N) uptake ratio and rCBV (rho=0.808, p≤0.0001). Significant negative correlation was demonstrated between the 99mTc-Tetrofosmin L/N ratio and ADC ratio (rho=−0.513, p=0.014). These imaging techniques were able to distinguish between low-grade and high-grade gliomas. ConclusionsFindings on DSC MRI and brain SPECT with 99mTc-Tetrofosmin metrics were more closely correlated with glioma cellular proliferation.