I came up with writing my own solution.
I’ve put that right after <?php do_action( ‘bbp_theme_before_topic_title’ ); ?>.
It checks if I wrote @pd@ in the thread title and adds based on other keywords images to the title and replaces it.
$sTitle = bbp_get_topic_title();
$bIsPred = strpos($sTitle, "@pd@");
if($bIsPred === false)
{
<a class="bbp-topic-permalink" href="<?php bbp_topic_permalink(); ?>" title="<?php bbp_topic_title(); ?>"><?php bbp_topic_title(); ?></a>
}
else
{
// check for other keywords in sTitle
}
