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What is A Bone marrow transplant recipient patient developed chest infection. On HRCT 'Tree in bud appearance' is seen. Most likely causative agent is - and explain in detail?
The 'tree-in-bud' sign is visible in high-resolution computed tomography (HRCT) and it is characterized by small centrilobular nodules of soft-tissue attenuation, connected to multiple branching linear structures of a similar caliber, originating from a single stalk.this is the main feature of pneumocystis jerovicii Ref Harrison20th edition pg 1079.