  The development of high-contrast capabilities has long been recognized as one
of the top priorities for the VLTI. As of today, the VLTI routinely achieves
contrasts of a few 10$^{-3}$ in the near-infrared with PIONIER (H band) and
GRAVITY (K band). Nulling interferometers in the northern hemisphere and
non-redundant aperture masking experiments have, however, demonstrated that
contrasts of at least a few 10$^{-4}$ are within reach using specific beam
combination and data acquisition techniques. In this paper, we explore the
possibility to reach similar or higher contrasts on the VLTI. After reviewing
the state-of-the-art in high-contrast infrared interferometry, we discuss key
features that made the success of other high-contrast interferometric
instruments (e.g., integrated optics, nulling, closure phase, and statistical
data reduction) and address possible avenues to improve the contrast of the
VLTI by at least one order of magnitude. In particular, we discuss the
possibility to use integrated optics, proven in the near-infrared, in the
thermal near-infrared (L and M bands, 3-5 $\mu$m), a sweet spot to image and
characterize young extra-solar planetary systems. Finally, we address the
science cases of a high-contrast VLTI imaging instrument and focus particularly
on exoplanet science (young exoplanets, planet formation, and exozodiacal
disks), stellar physics (fundamental parameters and multiplicity), and
extragalactic astrophysics (active galactic nuclei and fundamental constants).
Synergies and scientific preparation for other potential future instruments
such as the Planet Formation Imager are also briefly discussed.
