diff --git a/codeflash/context/unused_definition_remover.py b/codeflash/context/unused_definition_remover.py
index 00b077f63..3547623ae 100644
--- a/codeflash/context/unused_definition_remover.py
+++ b/codeflash/context/unused_definition_remover.py
@@ -638,7 +638,23 @@ def _analyze_imports_in_optimized_code(
             helpers_by_file_and_func[module_name].setdefault(func_name, []).append(helper)
             helpers_by_file[module_name].append(helper)
 
-    for node in ast.walk(optimized_ast):
+    # Collect only import nodes to avoid per-node isinstance checks across the whole AST
+    class _ImportCollector(ast.NodeVisitor):
+        def __init__(self) -> None:
+            self.nodes: list[ast.AST] = []
+
+        def visit_Import(self, node: ast.Import) -> None:
+            self.nodes.append(node)
+            # No need to recurse further for import nodes
+
+        def visit_ImportFrom(self, node: ast.ImportFrom) -> None:
+            self.nodes.append(node)
+            # No need to recurse further for import-from nodes
+
+    collector = _ImportCollector()
+    collector.visit(optimized_ast)
+
+    for node in collector.nodes:
         if isinstance(node, ast.ImportFrom):
             # Handle "from module import function" statements
             module_name = node.module