OBJECTIVETo summarize the chest CT features and outcome of necrotizing pneumonia (NP) caused by Mycoplasma pneumoniae in children and to review the changes of common inflammatory parameters in NP patients to help clinicians understand the proper timing of CT scan.

METHODThe imaging data from 30 cases of Mycoplasma pneumoniae pneumonia in NP group and 24 cases with non-necrotizing Mycoplasma penumoniae pneumonia (control group) were analyzed retrospectively. The changes of common inflammatory parameters in NP group and control group were compared.

RESULT(1) The chest CT findings of NP (30 cases): 28 cases showed unilateral pneumonia, and 20 cases showed single lobar consolidation, 10 cases had multiple lobes involvement; pulmonary cavities were seen in 27 cases. There were decreased enhancement areas in the consolidation (22 cases). (2) The dynamic changes of CT signs during follow-up: The CT scan performed during the 1 - 2 months after onset of disease (23 cases) showed that pulmonary consolidation in 2 cases (9%) were absorbed, 18 cases (78%)had cavities in lung, 16 cases (70%) had pleural thickening, 2 cases (9%) atelectasis and 1 case (4%) bronchopleural fistula;the CT scan performed during the 2 - 3 months after onset of disease (11 cases) showed pulmonary consolidation in 7 cases (64%) were absorbed, 10 cases (91%) pleural thickness, 7 cases (64%) with cavities in lung, 5 cases (45%) atelectasis, 2 cases (18%) pulmonary lobe cysts and 1 case bronchopleural fistula. The CT scan performed at 3.5 years of disease course (10 cases) showed that there were no pulmonary consolidation in any of the cases, 4 cases had atelectasis, 4 cases had pulmonary cysts, and 1 case had band-like scars. (3) There were significant differences between NP group and control group in the maximum peripheral blood WBC, proportion of neutrophil and C-reactive protein(CRP, mg/L) (P < 0.01, 0.01, 0.001, respectively), and there was significant difference between the 2 groups in the duration of fever, abnormal WBC(d) and CRP(d) (P < 0.001).

CONCLUSIONThe chest CT features of NP caused by Mycoplasma pneumoniae in children were single lobular consolidation in most cases, NP had decreased parenchymal enhancement and cavity in the consolidation, and recovery was slow, the outcome included recovery, atelectasis or lobar cystic degeneration. The clinicians should pay more attention to the common inflammatory parameters when they suspect the Mycoplasma pneumoniae pneumonia is progressing into necrosis and make correct decision for chest CT examination.