A Bone marrow transplant receipient patient developed chest infection. ON chest Xray Tree

on Bud appearance . The cause of this is

a.) klebsiella

b.) pneumocystis

c.) TB

d.) RSV

The tree-in-bud pattern is commonly seen at thin-section computed tomography (CT) of the lungs. It consists of small centrilobular nodules of soft-tissue attenuation connected to multiple branching linear structures of similar caliber that originate from a single stalk. Originally reported in cases of endobronchial spread of Mycobacterium tuberculosis, this pattern is now recognized as a CT manifestation of many diverse entities. These entities include peripheral airway diseases such as infection (bacterial, fungal, viral, or parasitic), congenital disorders, idiopathic disorders (obliterative bronchiolitis, panbronchiolitis), aspiration or inhalation of foreign substances, immunologic disorders, and connective tissue disorders and peripheral pulmonary vascular diseases such as neoplastic pulmonary emboli. Knowledge of the many causes of this pattern can be useful in preventing diagnostic errors

Respiratory syncytial virus (RSV) can result in lower respiratory tract infection. Bronchiolitis and bronchopneumonia are most commonly seen in infants and young children. RSV can also cause pneumonia in adults. High-resolution CT findings include ground-glass opacities, air-space consolidation, bronchial wall thickening and dilatation, and the tree-in-bud pattern . Air trapping can also be seen