Author(s)

Volker Hietschold¹, Andrij Abramyuk², Tareq Juratli³, Kerim Hakan Sitoci-Ficici³, Michael Laniado¹, Jennifer Linn²

¹Radiology, University Hospital Carl Gustav Carus, Dresden, Germany.
²Neuroradiology, University Hospital Carl Gustav Carus, Dresden, Germany.
³Neurosurgery, University Hospital Carl Gustav Carus, Dresden, Germany.

Dynamic measurements of T₁ shortening (dynamic contrast enhanced—DCE) as well as of T₂^* shortening (dynamic susceptibility contrast—DSC) as two separate measurement strategies are widely used to quantitatively describe tumor perfusion and vascularity. Dual-echo approaches allow for the simultaneous assessment of both effects. The extension to multi-echo sequences should inhere the advantage of improved signal-to-noise ratios and more precise sampling of the T₂^* decay. The aim of our study is to investigate, if an extension of the dual-echo approach to the multi-echo approach allows for more stable quantitative determination of pharmacokinetic parameters in brain tumors. This study applies a multi-echo approach to obtain different estimations of a vascular input function and analyzes various combinations of vascular input functions and pharmacokinetic models. Perfusion measurements were performed with 52 consecutive patients with different brain tumors using a 10-echo gradient echo sequence. Our findings show that the extension to multi-echo sequences leads to an 11%-improvement of the Contrast-to-Noise ratio. Compared to other combinations, an application of Extended Tofts model using the T₂^*-related venous output function or an output function estimated in the tumor tissue enables the most reliable determination of perfusion parameters, reducing the reproducibility range by a factor of 1.2 to 10 for K^trans and of 1.2 to 5.5 in the case of rBV calculation. Determination of K^trans within repeated measurements within about 3 days results as most stable, if AIF from tumor pixels is used as vascular input function, meaning that the scatter is reduced by a factor of 1.2 compared to the next best VIF and by a factor of 10 compared to the worst of the tested approaches. In addition, this study shows that signal decomposition into two components with different Larmor frequencies might provide additional information concerning tissue composition of brain tumors.

MRI, Brain Tumors, Perfusion

Hietschold, V. , Abramyuk, A. , Juratli, T. , Sitoci-Ficici, K. , Laniado, M. and Linn, J. (2017) Magnetic Resonance Perfusion in Brain Tumors: Comparison of Different Evaluation Approaches in Dual-Echo and Multi-Echo Techniques. International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, 6, 174-192. doi: 10.4236/ijmpcero.2017.62016.