  Dual and off-nucleus active supermassive black holes are expected to be
common in the hierarchical structure formation paradigm, but their
identification at parsec scales remains a challenge due to strict angular
resolution requirements. We conduct a systematic study using the Very Long
Baseline Array (VLBA) to examine 23 radio-bright candidate dual and off-nucleus
quasars. The targets are selected by a novel astrometric technique
("varstrometry") from Gaia, aiming to identify dual or off-nucleus quasars at
(sub)kilo-parsec scales. Among these quasars, 8 exhibit either multiple radio
components or significant (>3$\sigma$) positional offsets between the VLBA and
Gaia positions. The radio emission from the three candidates which exhibit
multiple radio components is likely to originate from small-scale jets based on
their morphology. Among the remaining five candidates with significant
VLBA-Gaia offsets, three are identified as potential dual quasars at parsec
scales, one is likely attributed to small-scale jets, and the origin of the
last candidate remains unclear. We explore alternative explanations for the
observed VLBA-Gaia offsets. We find no evidence for optical jets at kilo-parsec
scales, nor any contamination to Gaia astrometric noise from the host galaxy;
misaligned coordinate systems are unlikely to account for our offsets. Our
study highlights the promise of the varstrometry technique in discovering
candidate dual or off-nucleus quasars and emphasizes the need for further
confirmation and investigation to validate and understand these intriguing
candidates.
