From the Guidelines
Computed Tomography (CT) is the recommended imaging modality for evaluating the paranasal sinuses. A non-contrast CT scan provides excellent visualization of the bony anatomy, air-fluid levels, mucosal thickening, and potential obstructions in the sinus cavities, as noted in the study by 1. The scan should be performed in both coronal and axial planes for optimal assessment, with thin-slice (1-3mm) technique to allow for detailed evaluation of the ostiomeatal complex and other critical anatomical structures.
Key Points to Consider
- CT is particularly valuable before functional endoscopic sinus surgery (FESS) to map the surgical anatomy and identify potential complications like dehiscent skull base or proximity to orbital structures, as highlighted in the study by 1.
- While magnetic resonance imaging (MRI) may be used as a complementary study when soft tissue involvement, intracranial extension, or neoplastic processes are suspected, it is not the first-line imaging choice for routine sinus evaluation due to its inferior ability to demonstrate bony details, as discussed in the study by 1.
- Plain radiographs have largely been abandoned for sinus imaging due to their limited diagnostic value compared to the comprehensive information provided by CT scans, as stated in the study by 1.
- The American College of Radiology recommends CT of the paranasal sinuses without IV contrast for children with persistent sinusitis, recurrent sinusitis, or chronic sinusitis, or to define paranasal sinus anatomy before functional endoscopic sinus surgery, as outlined in the study by 1.
Additional Considerations
- MRI may be preferred in cases where there is a clinical concern for orbital or intracranial complications, or suspected invasive fungal sinusitis, as recommended in the study by 1.
- The choice of imaging modality should be guided by the specific clinical scenario and the potential benefits and risks of each modality, as emphasized in the studies by 1.
From the Research
Imaging Modalities for Paranasal Sinuses
The recommended imaging modality for paranasal sinuses depends on the specific condition being evaluated.
- For pathological-anatomical evaluation of paranasal sinus disease, CT is accepted as the gold standard 2.
- CT is especially useful for planning surgical procedures, and indications for paranasal sinus CT include trauma, malignant disease, and chronic sinusitis 2.
- MRI is the preferred imaging modality in malignant disease or complications of inflammatory sinus disease that extend beyond the limits of the paranasal sinuses 2.
Specific Conditions
- For fungal infections, CT scan has high diagnostic accuracy, with sensitivity, specificity, positive predictive value, and negative predictive value of 96.19%, 93.33%, 99.01%, and 77.77%, respectively 3.
- CT and MRI can be used to evaluate fungal sinusitis, with CT superior for detecting bony erosion and hyperdense fungal elements, and MRI exceling in evaluating soft tissue and mucosal involvement 4.
- Imaging findings can aid in early diagnosis and identification of complications, particularly in immunocompromised patients with acute invasive fungal sinusitis 4.