Stroke-associated pneumonia (SAP) is a common and serious complication after acute ischaemic stroke (AIS). Existing scores rely mainly on clinical variables, and the added prognostic value of inflammatory markers and early chest CT findings remains uncertain. We developed and externally validated an early multimodal model combining clinical severity, inflammation, and chest CT abnormalities, and explored risk-stratified associations between prophylactic antibiotics and SAP.

Inclusion criteria:

1. patients aged ≥18 years;
2. Admitted to a participating stroke centre with neuroimaging-confirmed acute ischaemic stroke ;
3. Had chest CT performed within 24 hours of stroke onset.

Exclusion criteria:

1. Pneumonia;
2. Chest CT images unavailable or incomplete for assessment;
3. Insufficient clinical documentation to ascertain stroke-associated pneumonia occurrence within 7 days after stroke onset

Adults (≥18 years) with neuroimaging-confirmed acute ischemic stroke admitted to participating tertiary stroke centers in China. Eligibility requires chest CT performed within 24 h of stroke onset . Patients will be retrospectively identified from electronic medical records and stroke registries, and stroke-associated pneumonia will be assessed within 7 days after stroke onset using prespecified criteria. Only the first eligible admission per individual will be included.

Related data will be shared if full study protocol and statistical analysis plan are provided with reasonable design.