<prompt> A 30 year old man presents with 6 month history of nasal discharge, facial pain and fever. On antibiotic therapy, fever subsided. After 1 month again had symptoms of mucopurulent discharge from the middle meatus and the mucosa of the meatus appeared congested and oedematous. Next best investigation would be:MRI of the sinusesNon-Contrast CT of the nose and para-nasal sinusesPlain x-ray of the para-nasal sinusesInferior meatus puncture  <response>: B i.e., Non contrast CT for nose paranasal sinuses Bacterial sinusitis is uncommon in patients whose symptoms have lasted for 7days. This diagnosis is reserved for patients with purulent nasal discharge and persistent symptoms i.e. symptoms lasting 7 days in adults or 10-14 days in children. CT or sinus radiography is not recommended in routine cases, paicularly early in course of disease 7 days dt high prevalence of acute viral rhinosinusitis. However, CT noncontrast of sinuses is the radiological investigation of choice in evaluation of persistent, recurrent, or chronic lasting 12 weeks sinusitisQ. Potts puffy tumor is advanced frontal sinusitis with soft tissue swelling pitting edema over frontal bone d t communicating subperiosteal abscess. 