How Useful can be CT Scan in the Differential Diagnosis of Pneumonia in Immunocompromised Children? The Experience at a Tertiary Care Pediatric Center

Abstract

Background and Objective: Identifying radiological findings evocative of pneumonia etiology in hematologic-pediatric patients is challenging, mainly due to the non-specificity of CT findings in this population. Materials and Methods: This is a retrospective study conducted in a tertiary care pediatric hospital. All hematological patients admitted from 02/01/2009 to 12/31/2021 with a chest CT-scan performed and an etiological diagnosis of pneumonia were included; we excluded pneumonia due to Pneumocystis jirovecii. Pneumonia etiological diagnosis was made by clinicians based on clinical, microbiological and radiological findings (according to guidelines) and was defined as "definite diagnosis". The primary aim was to identify radiological findings suggestive alone of specific pneumonia etiology, secondary aims were agreement among "radiological" and "definite diagnosis", and intra and inter-observer agreement. So, two radiologists (one Senior and one Junior), blinded to patient's characteristics and "definite diagnosis", performed two readings of CT-scans of included patients; for each reading, they hypothesized a "radiological diagnosis". To reach the primary aim a sub-analysis of the "radiological diagnosis" with the highest agreement with "definite diagnosis" was performed. Results: Twenty-four CT scans from 23 hematological patients were analyzed. Pneumonia's "definitive diagnosis" was fungal and bacterial in 16 and 8 cases, respectively; no definite diagnosis of viral pneumonia was identified in the period of study. Senior "radiological diagnosis" derived from the first reading (S1) was the one with the best agreement with "definite diagnosis" (83.3%). The sub-analysis of S1 suggested that no radiological findings were indicative alone of specific infectious etiology. Intra-observer agreement was higher comparing J1 vs. J2 than S1 vs. S2. Inter-observer agreement was slight. Conclusions: Our study confirms the non-specificity of CT-scan findings alone in children with hematologic diseases. However, senior expertise allowed us to achieve the correct radiological diagnosis (compared to "definite diagnosis") in 83% of CT-readings. We believe it's essential to teach the knowledge to the youngest, as the cooperation between infectious disease and radiologist specialists.