From the Guidelines
CT scans of the paranasal sinuses are not routinely necessary for most patients with chronic allergic rhinitis, but should be considered when patients have persistent symptoms despite appropriate medical therapy, when complications are suspected, or when surgical intervention is being contemplated. This approach is supported by the most recent and highest quality study, which emphasizes the importance of reserving CT scans for cases where initial management fails or when symptoms suggest complications 1. The use of CT scans in evaluating sinus disease is well-established, with multiplanar CT imaging offering the advantage of both bone detail and soft-tissue imaging, and low-dose protocols reducing patient radiation exposure 1.
When considering the use of CT scans, it is essential to weigh the benefits against the potential risks, including radiation exposure. However, with modern techniques, the radiation exposure from CT scans is relatively low, making them a valuable diagnostic tool in specific cases. The European Position Paper on Rhinosinusitis and Nasal Polyps 2020 recommends CT scans as the gold standard in the radiologic evaluation of rhinologic disease, notably chronic rhinosinusitis 1.
In patients with chronic allergic rhinitis, initial management typically includes allergen avoidance, intranasal corticosteroids, antihistamines, and saline irrigation. CT scanning should be reserved for cases where these treatments fail or when symptoms suggest complications, such as persistent symptoms, suspected complications, or when surgical intervention is being contemplated. The most useful information for evaluating sinus disease can be obtained from non-contrast CT scans with thin slices (1-3mm) in both coronal and axial planes.
Key points to consider when evaluating the use of CT scans in patients with chronic allergic rhinitis include:
- The importance of reserving CT scans for specific cases, such as persistent symptoms or suspected complications
- The benefits of multiplanar CT imaging in evaluating sinus disease
- The need to weigh the benefits of CT scans against the potential risks, including radiation exposure
- The recommendation to use non-contrast CT scans with thin slices in both coronal and axial planes to obtain the most useful information for evaluating sinus disease.
From the Research
Importance of CT Scan in Evaluating Chronic Allergic Rhinitis
- A computed tomography (CT) scan of the paranasal sinuses is crucial in the evaluation of patients with chronic allergic rhinitis, as it helps to identify the extent of sinus involvement and guide treatment decisions 2, 3, 4, 5, 6.
- CT scans can detect mucosal thickening, opacification, and air-fluid levels in the sinuses, which are common findings in chronic rhinosinusitis 2, 4, 5.
- The use of low-dose CT scans has been shown to be more effective than plain X-ray in diagnosing sinus abnormalities, particularly in the frontal, ethmoidal, and sphenoidal sinuses 2.
- CT scans can also help to identify complications of sinusitis, such as orbital and intracranial involvement, which require prompt recognition and treatment 4.
Comparison of CT Scan Findings in Allergic and Non-Allergic Patients
- Studies have compared CT scan findings in patients with chronic rhinosinusitis with and without allergy, and found that maxillary mucosal thickening and frontal hypoplasia are more common in allergic patients 5.
- However, the presence of these findings does not necessarily correlate with the severity of symptoms or quality of life in patients with chronic rhinosinusitis 3.
- CT scan findings can be used to guide the evaluation of allergy in patients with chronic rhinosinusitis, but should be interpreted in conjunction with clinical findings and other diagnostic tests 5, 6.
Clinical Significance of CT Scan Findings
- The presence of sinusitis on CT scan is more common in patients with perennial allergic rhinitis than in controls, suggesting a possible link between allergy and sinusitis 6.
- However, the exact mechanism of this association is not clear, and further studies are needed to determine the relationship between allergy and sinusitis 6.
- CT scan findings can be used to inform treatment decisions and guide the management of patients with chronic allergic rhinitis and sinusitis 2, 3, 4, 5, 6.