Prepare a vegetable broth with the celery, carrots and onion. Wash the radicchio, drain it, and cut it into long, thin slices. Sauté the garlic in a pan with the oil and add the radicchio. Season with salt, pour in the white wine and deglaze. When the radicchio is well-braised, add the rice and cook, pouring in the broth gradually. Allow to cook for approximately 18 minutes.