A 16-year-old boy sustained blunt trauma to his abdomen when he struck a bridge abutment at high speed while driving a motor vehicle. Peritoneal lavage shows a hemoperitoneum, and at laparotomy, a small portion of the left lobe of the injured liver is removed. Two months later, a CT scan of the abdomen shows that the liver has nearly regained its size before the injury. Which of the following processes best explains this CT scan finding?