Radiological characteristics and CT-MRI combined evaluation of four atypical type 2 decompression sickness cases: a single-center retrospective study

This study aimed to analyze the clinical and imaging characteristics of atypical Type 2 Decompression Sickness (T2DCS), summarize its diagnostic imaging clues, clarify the clinical significance of heterogeneous manifestations and complex diagnosis-treatment histories, and provide systematic clinical evidence for the diagnosis and treatment of similar cases, addressing the scarcity of systematic reports on atypical T2DCS and its high misdiagnosis rate in emergency practice. A single-center retrospective study was conducted at the PLA Navy No.971 Hospital, enrolling 4 male professional commercial divers with atypical T2DCS admitted from December 2023 to December 2025. Clinical, diving, imaging (chest/abdominal CT and CNS MRI) and treatment data were collected and cross-validated. Imaging findings were assessed via independent, clinical information-masked imaging evaluation, and descriptive statistical analysis was performed with SPSS 26.0. All patients received standardized recompression therapy per US Navy Table 6 A. The 4 patients (mean age 50.5 ± 7.92 years) all had rapid surfacing (≤ 10 min), with 2 having prolonged diving (> 4 h). Clinical symptoms were heterogeneous, involving the respiratory, digestive and nervous systems. Imaging featured multisite cross-system pneumatosis (detected by CT) and multisegmental CNS lesions (localized by MRI). Most patients achieved symptom relief after standardized therapy, while 1 case had poor prognosis due to prehospital nonstandard recompression therapy with severe pressure fluctuations and insufficient duration. Atypical T2DCS has heterogeneous clinical manifestations and is prone to misdiagnosis, requiring careful collection of diving exposure history.The combined CT-MRI evaluation may improve diagnostic confidence and assist in identifying multisystem involvement in atypical T2DCS. Early standardized recompression therapy is the core treatment for improving prognosis, and prehospital nonstandard treatment may exacerbate the condition, providing critical clinical references for managing atypical T2DCS.