A patient presents with decreased vital capacity and total Lung volume. What is the most probable diagnosis?

Reduced lung volumes are a reflection of the restrictive lung disease seen in sarcoidosis. In bronchiectasis,there will be increased lung volume and purulence due to obstructive disease.The earliest chest Xray change in CF lungs is hyperinflation,reflecting small airways obstruction.In asthma,there may be increased airway resistance and may show increased total lung capacity and residual volume. Reference:Harrison's Medicine-18th edition,page no:2808,2149