Final answer:
Road mapping DSA is the angiographic technique utilized for precise positioning of a guide wire through torturous vessels by providing real-time visual guidance.
Step-by-step explanation:
The special angiographic image post-processing technique that allows for precise positioning of a guide wire through torturous vessels is known as road mapping Digital Subtraction Angiography (DSA). This technique involves acquiring a live fluoroscopic image of the vessels after contrast media injection and then digitally subtracting pre-contrast images, leaving an outline of the vessels. The guide wire can then be navigated through the vessels with real-time visual guidance, improving the accuracy of interventional procedures in complex vascular anatomy.