Cook the pasta al dente according to package directions. Drain well, return to the pot, and cover to keep warm.

While the pasta is cooking, coat a large nonstick skillet with nonstick olive oil cooking spray, and preheat over medium-high heat. Add the sausage, zucchini, mushrooms, red pepper, and garlic, and stir-fry for about 3 minutes, or until the sausage is browned and the vegetables are crisp-tender. Cover the skillet periodically if it begins to dry out. (The steam from the cooking vegetables will moisten the skillet.) Add a few teaspoons of water to the skillet if needed.

Transfer the sausage and vegetables to a large bowl, and cover to keep warm. Add the broth and oregano to the skillet, and cook uncovered over medium-high heat, stirring frequently, for a couple of minutes, or until the broth is reduced by half.

Add the tomatoes to the skillet, cover, and cook over medium-high heat for about 1 minute, or until the tomatoes are heated through and beginning to soften.

Reduce the heat to medium, and add the pasta and the sausage-vegetable mixture to the skillet. Toss for a minute or 2 to blend the flavors, adding a little more broth if the mixture seems too dry. Serve hot, topping each serving with a tbsp of Parmesan, if desired.