The poor elevation resolution in a linear scan (left image) is overcome by the proposed bi-directional scanning approach that yields isotropic transverse resolution (right).Optoacoustic (photoacoustic) imaging is often performed with one-dimensional transducer arrays, in analogy to ultrasound imaging. Optoacoustic imaging using linear arrays offers ease of implementation but comes with several performance drawbacks, in particular poor elevation resolution, i.e. the resolution along the axis perpendicular to the focal plane. Herein, we introduce and investigate a bi-directional scanning approach using linear arrays that can improve the imaging performance to quasi-isotropic transverse resolution. We study the approach theoretically and perform numerical simulations and phantom measurements to evaluate its performance under defined conditions. Finally, we discuss the features and the limitations of the proposed method.