An mucosal impedance (“MI”) device may include or utilize a retaining member sized to retain a tines structure including N tines, each provided with one or more impedance electrodes on each tine. The retaining member may mechanically deform the tines such that they fit inside it. The tines, made of spring like material, may be chosen, for example, for their elastic modulus and yield strength. The tines may be pre-conditioned with a shape that provides a spring tension force in the radial outward direction. When the retaining member or is retracted to release and expose the tines and impedance electrodes, the preconditioned shape and elasticity of the tines cause the tines to expand radially outward, providing an appropriate contact force of the impedance electrodes on the inner wall of the esophagus for a range of esophageal diameters.
