Application of imaging studies for orbital tumors: a practical review and representative cases.

Orbital imaging has undergone a significant transformation over the past few decades, evolving from basic radiographic techniques to sophisticated cross-sectional imaging modalities. Historically, conventional radiography was limited to visualizing only the bony structures of the orbit or radiodense foreign bodies, making it inadequate for detecting soft tissue pathology. Advances in imaging over the last several decades-first with computed tomography (CT) in the 1970s and later with magnetic resonance imaging (MRI) in the 1980s-have revolutionized orbital diagnostics by enabling detailed visualization of both osseous and soft tissue structures. Magnetic resonance imaging (MRI) has emerged as the preferred modality for evaluating orbital tumors and other soft tissue lesions. Its superior soft tissue resolution, multiplanar imaging capability, and ability to characterize lesion morphology and extent make it crucial in clinical practice. MRI is especially valuable in differentiating benign from malignant lesions, evaluating involvement of critical structures such as the globe, optic nerve, extraocular muscles, and vascular components, and assessing disease at the orbital apex or with suspected intracranial extension. Advanced MRI techniques, including diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) MRI, further enhance diagnostic accuracy. In pediatric populations, MRI holds particular importance due to its lack of ionizing radiation and its effectiveness. In contrast, while CT offers superior resolution of bony anatomy and is useful for detecting calcifications and fractures, it is somewhat limited in soft tissue differentiation and involves exposure to ionizing radiation. While CT examination can be tailored to evaluate bone or soft tissues, orbital CT is typically reserved for cases requiring detailed osseous assessment, acute trauma settings, or for patients who cannot undergo an MRI. MRI creates high-resolution images by detecting signals emitted by hydrogen nuclei when exposed to a strong magnetic field and radiofrequency pulses. Differences in signal based on tissue composition and water content are captured and converted into high-resolution images. Interpreting orbital lesions requires standardized terminology.