What diagnostic test is first-line for diagnosing mastoiditis?

The first-line diagnostic test for mastoiditis is a CT scan. CT imaging is preferred because it provides detailed cross-sectional images of the temporal bone and surrounding structures, allowing for visualization of the mastoid air cells and any potential complications that may arise from mastoiditis, such as abscess formation or intracranial extension of the infection. This level of detail is crucial for confirming the diagnosis and guiding further management.

Other imaging modalities, while useful in certain contexts, do not provide the same comprehensive view as a CT scan. MRI can be more effective in assessing soft tissue and intracranial complications but is not routinely used as a first-line test for mastoiditis due to its higher cost and longer acquisition time. X-rays have limited utility in this scenario, as they do not provide sufficient detail of the mastoid structure or the extent of disease. Ultrasound can be helpful in some pediatric cases, especially in younger children, for assessing superficial conditions but lacks the specificity and details necessary for a definitive diagnosis of mastoiditis.