Differentiating skull base chordomas and invasive pituitary adenomas with conventional MRI

Background It is difficult to distinguish between invasive pituitary adenomas (IPAs) and skull base chordomas based on tumor location and clinical manifestations. Purpose To investigate the value of the apparent diffusion coefficient (ADC), T2-weighted (T2W) imaging, and dynamic contrast enhancement (DCE) in differentiating skull base chordomas and IPAs. Material and Methods Data for 21 patients with skull base chordomas and 27 patients with IPAs involving the paranasal sinus were retrospectively reviewed, and all diagnoses were pathologically confirmed. Each patient underwent conventional 3.0 T magnetic resonance imaging (MRI), including, ADC, T2W imaging, and DCE sequences. Regions of interest were drawn in the mass and in normal white matter on ADC maps and T2W imaging. The mean ADC, normal ADC, T2W imaging signal intensity (SI), and relative T2-weighted (rT2W) imaging values were measured. DCE parameters, including types of time signal-intensity curves (TIC), enhancement peak (EP), and maximum contrast enhancement ratio (MCER), were calculated. Differences between skull base chordomas and IPAs were evaluated using the independent samples t-test. Receiver operating characteristic (ROC) curve analyses were also performed. Results When comparing IPAs and chordomas, there were significant differences in mean ADC, normal ADC, rT2W imaging values, TIC, EP, and MCER ( P < 0.01). The areas under curves in the ROC analyses for normal ADC, mean ADC, T2W imaging, rT2W imaging, TIC, EP, and MCER were 1.0, 0.996, 1.0, 0.81, 0.987, and 0.987, respectively. Conclusion ADC, T2W imaging SI, and DCE-related parameters can contribute to the differential diagnosis of skull base chordomas and IPAs.