Human liver <scp>CEST</scp> imaging at 7 T: Impact of B1+ shimming

In this study, we have demonstrated for the first time the feasibility of acquiring and quantifying relaxation-compensated CEST contrasts in the human liver at ultrahigh field. The application of static pTx effectively eliminates <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:msubsup><mml:mi>B</mml:mi> <mml:mn>1</mml:mn> <mml:mo>+</mml:mo></mml:msubsup> </mml:mrow> <mml:annotation>$$ {B}_1^{+} $$</mml:annotation></mml:semantics> </mml:math> dropouts and allows for accurate CEST contrast quantification within the selected ROI. In addition, the proposed <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:msubsup><mml:mi>B</mml:mi> <mml:mn>1</mml:mn> <mml:mo>+</mml:mo></mml:msubsup> </mml:mrow> <mml:annotation>$$ {B}_1^{+} $$</mml:annotation></mml:semantics> </mml:math> mapping technique shows efficacy for enhanced MTR_Rex B₁ corrections in the abdomen.