Idiopathic pulmonary fibrosis (IPF) is a disease characterized by the hardening and loss of elasticity of the lungs, a condition in which there is an increase in connective tissue in the lungs called fibrosis. This increase in connective tissue disrupts the structure of the lung tissue. Thorax HRCT is the most important test for the diagnosis. Pulmonary function tests show a restrictive pattern. There is no cure for the disease.