Dynamic and simultaneous MR measurement of R₁ and R₂* changes during respiratory challenges for the assessment of blood and tissue oxygenation.

Remmele, Stefanie; Sprinkart, Alois M.; Müller, Andreas; Träber, Frank; von Lehe, Marec; Gieseke, JürgEN; Flacke, Sebastian; Willinek, Winfried A.; Schild, Hans H.; Sénégas, JuliEN; Keupp, JochEN; Mürtz, Petra

This work presents a novel method for the rapid and simultaneous measurement of R1 and R2* relaxation rates. It is based on a dynamic short repetition time steady-state spoiled multigradient-echo sequence and baseline R1 and B1 measurements. The accuracy of the approach was evaluated in simulations and a phantom experiment. The sensitivity and specificity of the method were demonstrated in one volunteer and in four patients with intracranial tumors during carbogen inhalation. We utilized (Δ R2*, Δ R1) scatter plots to analyze the multiparametric response amplitude of each voxel within an area of interest. In normal tissue R2* decreased and R1 increased moderately in response to the elevated blood and tissue oxygenation. A strong negative Δ R2* and Δ R1 response was observed in veins and some tumor areas. Moderate positive Δ R2* and Δ R1 response amplitudes were found in fluid-rich tissue as in cerebrospinal fluid, peritumoral edema, and necrotic areas. The multiparametric approach was shown to increase the specificity and sensitivity of oxygen-enhanced MRI compared to measuring Δ R2* or Δ R1 alone. It is thus expected to provide an optimal tool for the identification of tissue areas with low oxygenation, e.g., in tumors with compromised oxygen supply. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.

Magnetic Resonance in Medicine, 2013, Vol 70, Issue 1, p136

0740-3194

Academic Journal

10.1002/mrm.24458