Impression-Based Imaging Severity Stratification in Adult Acute Chest Syndrome Using Structured Radiology Report Classification

Purpose: Acute chest syndrome (ACS) is a major cause of morbidity and mortality in adults with sickle cell disease (SCD), yet radiographic severity remains inconsistently defined in routine clinical practice. Adult patients frequently demonstrate overlapping acute and chronic pulmonary abnormalities, limiting applicability of existing pediatric classification systems. This study aimed to develop a structured, impression-based imaging classification framework for adult ACS and to evaluate associations between imaging patterns and clinical outcomes.

Methods/Materials: We conducted a retrospective study of adult patients with SCD admitted between 2015 and 2025 at a single academic center. Radiology impressions from chest radiographs and CT were extracted and processed using a rule-based algorithm that classified pulmonary findings by acuity (definite, possible, or none) and chronicity. These classifications were linked to patient outcomes, such as 30-day mortality.

Results: 5,586 imaging studies from 385 patients were analyzed. Definite acute pulmonary findings were identified in 1704 studies (30.5%), with an additional 74 studies (1.3%) demonstrating possible acute findings. Chronic pulmonary abnormalities were present in 942 studies (16.9%), and 331 studies (5.9%) demonstrated acute-on-chronic pulmonary patterns.

Additionally, 243 patients (63.1%) exhibited at least one acute imaging finding, and 108 patients (28.1%) demonstrated acute-on-chronic pulmonary patterns across serial encounters. 30-day mortality occurred in 17 (4.4%), and overall mortality in 27 patients (7.0%). Patients with acute findings, accompanied by chronic abnormalities, demonstrated higher rates of both 30-day and overall mortality compared with patients without such findings.

Conclusions: Structured classification of radiographic impression enables reproducible stratification of acute and chronic lung findings in adults with SCD. Acute and acute-on-chronic imaging patterns were associated with increased short-term and overall mortality, suggesting that imaging features capture clinical disease severity. This framework provides a foundation for integrating radiology impressions with clinical course to support future severity modeling in ACS.