exclude subcategories – no show

Thank you for this great plugin.

now show in my theme categories using this code.

<div id=”categories”>
<?php foreach (get_categories() as $cat) : ?>
<div class=”imagencat”>term_id); ?>”><img src=”<?php echo z_taxonomy_image_url($cat->term_id); ?>” /></div>
<?php endforeach; ?>
</div>

but I would exclude not display sub-categories, there is a way to only show categories?

thanks

http://wordpress.org/extend/plugins/categories-images/