Researchers developed new criteria for staging bladder tumors using CT scans to improve accuracy. They compared different tumor shapes and sizes to create objective guidelines. They found that certain tumor shapes corresponded to specific stages, with protrusion beyond the bladder wall indicating more advanced stages. By using a specific ratio of tumor dimensions, they could distinguish between different stages with high accuracy, especially when using air as a contrast agent. This new method allows for better diagnosis of deep-seated bladder tumors, making it a valuable tool in clinical practice.