To show the principle feasibility of imaging the electric conductivity of lungs using Ultrashort Echo-Time (UTE)-sequencesReliable MR imaging of lung tissue could be an important element of diagnosing lung-related diseases like lung cancer, pneumonia, or Chronic Obstructive Pulmonary Disease (COPD). The very short T2 components of lung tissue, one of the main problems of MR lung imaging, can be visualized using sequences with ultrashort echo times (UTE) [1,2]. Furthermore, UTE sequences allow the determination of electric conductivity of the imaged tissue [3,4]. The conductivity determination can be based on the phase of the MR image, as long as this phase is only related to B₁ effects and not affected by B₀ effects (i.e., main field inhomogeneity or off-resonance) [5]. This pre-condition is sufficiently fulfilled for UTE sequences, since B₀ phase contributions are proportional to the echo time applied. This study applied UTE sequences to investigate the principle feasibility of lung conductivity imaging, examining healthy volunteers.UTE was applied to the lungs of 5 healthy volunteers (informed consent obtained) using a 3T MR system (Philips Ingenia, Best, The Netherlands) with 2-TX-channel RF shimming and an anterior/posterior RX coil array. UTE was performed with a 3D radial ("koosh-ball") k-space trajectory (TR/TE = 1.9/0.06 ms, flip angle 2°, isotropic voxel size 2.3×2.3×2.3 mm³, scan duration 28 s). Scans were repeated twice with expiration and inspiration breath hold. With φ the image phase, μ₀ the magnetic vacuum permeability, and ω the Larmor frequency, conductivity σ was reconstructed via $$$ σ = {\nabla}^2φ/(2μ_0ω) $$$ [5] and a subsequent median filter. Kernel size of both, numerical differentiation and median filter, was locally adapted not to cross tissue boundaries.For both, inspiration and expiration breath hold of one of the volunteers, UTE reformats and corresponding conductivity maps are shown in Fig. 1 and conductivity histograms in Fig. 2. The median conductivity of expiration and inspiration breath hold is 0.45 S/m and 0.05 S/m, respectively. The average over all volunteers investigated is 0.55 ± 0.21 S/m and 0.16 ± 0.14 S/m, respectively.This study showed the feasibility of lung conductivity mapping with UTE. The reconstructed conductivity was lower for inspiration breath hold than for expiration breath hold. This is the expected behaviour, since the fraction of air (with nearly zero conductivity) inside the lungs should be higher during inspiration than during expiration; this is confirmed by literature values [6]. Thus, pathologic lung tissue could be characterized by UTE-based conductivity imaging, particularly reflecting the electrolyte content of the tissue, but also its water and air content.