[Clinical characteristics and CT findings of Pneumocystis Jirovecii pneumonia in 46 cases with hematological diseases].

Objective: To summarize the original CT features of Pneumocystis Jirovecii pneumonia in patients with hematological diseases. Methods: A retrospective analysis was carried out in 46 patients with proven pneumocystis pneumonia (PJP) in the Hospital of Hematology, Chinese Academy of Medical Sciences between January 2014 and December 2021. All patients had multiple chests CT and related laboratory examinations, imaging typing were conducted based on the initial CT presentation, and the distinct imaging types were analyzed against the clinical data. Results: In the analysis, there were 46 patients with proven pathogenesis, 33 males, and 13 females, with a median age of 37.5 (2-65) years. The diagnosis was validated by bronchoalveolar lavage fluid (BALF) hexamine silver staining in 11 patients and clinically diagnosed in 35 cases. Of the 35 clinically diagnosed patients, 16 were diagnosed by alveolar lavage fluid macrogenomic sequencing (BALF-mNGS) and 19 by peripheral blood macrogenomic sequencing (PB-mNGS) . The initial chest CT presentation was categorized into 4 types, including ground glass (GGO) type in 25 cases (56.5%) , nodular type in 10 cases (21.7%) , fibrosis type in 4 cases (8.7%) , and mixed type in 5 cases (13.0%) . There was no substantial discrepancy in CT types among confirmed patients, BALF-mNGS diagnosed patients and PB-mNGS diagnosed patients (χ(2)=11.039, P=0.087) . The CT manifestations of confirmed patients and PB-mNGS diagnosed patients were primarily GGO type (67.6%, 73.7%) , while that of BALF-mNGS diagnosed patients were nodular type (37.5%) . Of the 46 patients, 63.0% (29/46) had lymphocytopenia in the peripheral blood, 25.6% (10/39) with positive serum G test, and 77.1% (27/35) with elevated serum lactate dehydrogenase (LDH) . There were no great discrepancies in the rates of lymphopenia in peripheral blood, positive G-test, and increased LDH among different CT types (all P>0.05) . Conclusion: The initial chest CT findings of PJP in patients with hematological diseases were relatively prevalent with multiple GGO in both lungs. Nodular and fibrosis types were also the initial imaging findings for PJP.