My son had chronic sinusitis, and before surgery our doctor recommended a nasal endoscopy first to look inside his nose and check what was causing the blockage. A CT scan was only arranged because the symptoms had been going on for quite some time and it helped with planning the surgery. We saw Dr Lau, a Paediatric ENT doctor in Singapore, and I felt those tests gave us a much better understanding of what was going on before making any decisions.