When to Order Imaging for Sinonasal Disease: ACR Appropriateness Decoded
When to Order Imaging for Sinonasal Disease: ACR Appropriateness Decoded
A patient presents with facial pain, pressure, and purulent nasal discharge. It seems like straightforward acute sinusitis, but they also mention a new-onset headache and blurry vision. Is this a simple infection, or is there an orbital or intracranial complication brewing? Deciding between a CT, an MRI, or no imaging at all requires balancing diagnostic yield with radiation exposure and cost. The American College of Radiology (ACR) Appropriateness Criteria provide an evidence-based framework for these decisions. This guide decodes the latest ACR recommendations for sinonasal disease, helping you choose the right study for the right clinical scenario.
What Does ACR Sinonasal Disease Cover?
The ACR Appropriateness Criteria for Sinonasal Disease, developed by the Neurologic panel, address the evaluation of inflammatory conditions, suspected masses, and structural abnormalities of the paranasal sinuses and nasal cavity. These guidelines provide imaging recommendations for a range of common clinical presentations, from uncomplicated acute rhinosinusitis to more complex and urgent scenarios.
The criteria cover initial imaging for:
- Acute, uncomplicated rhinosinusitis (less than 4 weeks).
- Acute rhinosinusitis with suspected orbital or intracranial complications.
- Recurrent, chronic, or noninvasive fungal sinusitis, often in surgical candidates.
- Rapidly progressing sinusitis or suspected invasive fungal disease.
- Suspected sinonasal masses.
- Suspected cerebrospinal fluid (CSF) leaks.
These guidelines are focused on initial diagnostic imaging and do not cover post-treatment follow-up, surveillance, or imaging for conditions primarily related to craniofacial trauma, which are addressed in separate ACR documents.
What Imaging Should I Order for Sinonasal Disease? Recommendations by Clinical Scenario
Choosing the optimal imaging modality for sinonasal disease depends entirely on the clinical context. The ACR provides specific guidance for distinct scenarios, emphasizing that for the most common presentation, no imaging is needed at all.
For acute (less than 4 weeks) uncomplicated rhinosinusitis, the ACR states that nearly all forms of imaging are Usually Not Appropriate. This includes CT, MRI, and plain radiography. The diagnosis in these cases is clinical, and imaging does not typically alter management. Unnecessary imaging exposes patients to radiation and cost without providing clinical benefit.
When there is suspicion of a complication, the recommendations change significantly. For acute rhinosinusitis with suspected orbital or intracranial complication, both MRI head without and with IV contrast and MRI orbits face neck without and with IV contrast are rated as Usually Appropriate. These studies excel at evaluating soft-tissue extension into the orbit or brain. CT maxillofacial with IV contrast is also Usually Appropriate and is often more readily available, providing excellent bony detail and assessment of abscess formation.
For patients with acute recurrent sinusitis, chronic rhinosinusitis, or noninvasive fungal sinusitis who are possible surgical candidates, CT maxillofacial without IV contrast is Usually Appropriate. This study provides the detailed bony anatomy of the ostiomeatal complex that surgeons require for preoperative planning. For more on CT imaging in this region, see our guide to CT Brain Without Contrast.
In cases of acute sinusitis with rapid progression or suspected invasive fungal sinusitis—a medical emergency—prompt and thorough imaging is critical. The ACR rates MRI orbits face neck without and with IV contrast, CT maxillofacial with IV contrast, and CT maxillofacial without IV contrast as Usually Appropriate. MRI is particularly sensitive for detecting early intracranial or cavernous sinus invasion, while CT is excellent for identifying bony erosion.
If a suspected sinonasal mass is the primary concern, the same three studies are rated Usually Appropriate: MRI orbits face neck without and with IV contrast, CT maxillofacial with IV contrast, and CT maxillofacial without IV contrast. Often, both CT and MRI are used complementarily to fully characterize the lesion, with CT defining bony involvement and MRI delineating soft-tissue extent. For vascular evaluation in this context, refer to our guide on MRA Neck With and Without Contrast.
Finally, for a suspected CSF leak, the initial imaging of choice is CT maxillofacial without IV contrast, which is rated Usually Appropriate. High-resolution, thin-section CT can often identify the bony defect in the skull base responsible for the leak. If this is nondiagnostic, more specialized tests like CT cisternography may be considered.
ACR Imaging Recommendations Table
| Clinical Scenario | Top Procedure | ACR Rating | Adult RRL | Pediatric RRL |
|---|---|---|---|---|
| Acute (less than 4 weeks) uncomplicated rhinosinusitis. Initial Imaging. | Imaging of any kind | Usually Not Appropriate | N/A | N/A |
| Acute rhinosinusitis with suspected orbital or intracranial complication. Initial Imaging. | MRI head without and with IV contrast | Usually Appropriate | O 0 mSv | O 0 mSv [ped] |
| Acute recurrent sinusitis or chronic rhinosinusitis or noninvasive fungal sinusitis or sinonasal polyposis. Possible surgical candidate. Initial Imaging. | CT maxillofacial without IV contrast | Usually Appropriate | ☢ ☢ 0.1-1mSv | ☢ ☢ ☢ 0.3-3 mSv [ped] |
| Acute sinusitis with rapid progression or suspected invasive fungal sinusitis. Initial Imaging. | MRI orbits face neck without and with IV contrast | Usually Appropriate | O 0 mSv | O 0 mSv [ped] |
| Suspected sinonasal mass. Initial Imaging. | MRI orbits face neck without and with IV contrast | Usually Appropriate | O 0 mSv | O 0 mSv [ped] |
| Suspected CSF leak. Initial Imaging. | CT maxillofacial without IV contrast | Usually Appropriate | ☢ ☢ 0.1-1mSv | ☢ ☢ ☢ 0.3-3 mSv [ped] |
Adult vs. Pediatric Sinonasal Disease Imaging: Radiation Dose Tradeoffs
When ordering imaging for children, minimizing radiation exposure is a primary concern due to their increased radiosensitivity and longer life expectancy, which allows more time for potential long-term effects of radiation to manifest. The principle of As Low As Reasonably Achievable (ALARA) is paramount.
The ACR guidelines reflect this by providing separate pediatric relative radiation level (RRL) estimates. For instance, a CT maxillofacial scan, which falls in the ☢ ☢ (0.1-1 mSv) category for adults, is rated as ☢ ☢ ☢ (0.3-3 mSv) for pediatric patients. This difference highlights that pediatric protocols may require adjustments, but the overall dose remains a significant consideration. Whenever possible, non-ionizing modalities like MRI are preferred in children, especially when soft-tissue evaluation is the primary goal, such as in cases of suspected orbital or intracranial complications. When CT is necessary, such as for pre-surgical planning in chronic sinusitis, protocols should be optimized to use the lowest possible dose that still achieves diagnostic image quality.
Imaging Protocol Details for Sinonasal Disease
Once you’ve decided on the right study, the specific imaging protocol is critical for obtaining diagnostic-quality images. Details such as slice thickness, the use and timing of intravenous contrast, and specific MRI sequences can make the difference in identifying subtle pathology. Our protocol guides offer a deeper dive into the technical considerations for the studies recommended above.
Tools to Help You Order the Right Study
Navigating imaging guidelines and protocols can be complex. GigHz provides a suite of reference tools designed to support clinical decision-making at the point of care.
The ACR Appropriateness Criteria Lookup allows you to quickly search the full ACR guidelines for thousands of clinical scenarios beyond sinonasal disease, ensuring you have evidence-based support for your imaging orders.
For detailed procedural information, the Imaging Protocol Library provides standardized, scannable protocols for a wide range of CT, MRI, and other imaging studies, helping to ensure consistency and quality.
To help with patient communication and tracking cumulative exposure, the Radiation Dose Calculator offers a simple way to estimate and explain the radiation dose associated with common imaging procedures.
Why is imaging “usually not appropriate” for uncomplicated acute sinusitis?
For acute rhinosinusitis (symptoms <4 weeks) without signs of complication (e.g., high fever, severe headache, vision changes, cranial nerve deficits), the diagnosis is made clinically. Imaging findings, such as mucosal thickening, are nonspecific and do not reliably distinguish between viral and bacterial causes. Since management is typically medical and not altered by imaging results, the ACR recommends against routine imaging to avoid unnecessary radiation exposure and healthcare costs.
When is contrast necessary for a CT scan of the sinuses?
Intravenous contrast is essential when there is a concern for a complicated infection or a potential mass. Contrast enhances areas of inflammation, infection, and vascularity, helping to delineate abscesses, identify extension of infection outside the sinuses (e.g., into the orbit or brain), and characterize tumors. For routine evaluation of chronic sinusitis or for surgical planning, a non-contrast CT is typically sufficient to assess bony anatomy and mucosal disease.
Is a plain film X-ray ever useful for evaluating sinonasal disease?
According to the current ACR Appropriateness Criteria, plain radiography of the paranasal sinuses is rated as “Usually Not Appropriate” for all listed clinical scenarios. While historically used, plain films have low sensitivity and specificity for sinonasal pathology and have been largely replaced by cross-sectional imaging like CT and MRI, which provide far superior anatomical detail.
What is the main difference between CT and MRI for evaluating sinonasal disease?
CT and MRI provide complementary information. CT is superior for evaluating fine bony detail, making it the ideal choice for assessing the ostiomeatal unit for surgical planning in chronic sinusitis, identifying bony erosion from aggressive infections or tumors, and detecting skull base defects in CSF leaks. MRI offers superior soft-tissue contrast, making it the best modality for evaluating the extent of disease into adjacent soft tissues, the orbits, or intracranially. It is the preferred study for suspected complications of sinusitis and for characterizing sinonasal masses.
How should I begin the workup for a suspected CSF leak?
The initial imaging study recommended by the ACR for a suspected cerebrospinal fluid (CSF) leak is a high-resolution, non-contrast CT of the maxillofacial bones and skull base. This study is performed with thin slices to meticulously search for a bony defect that could be the source of the leak. If the non-contrast CT is negative or equivocal, more advanced techniques like CT cisternography or nuclear medicine cisternography may be required to directly visualize the site of active leakage.
Reviewed by Pouyan Golshani, MD, Interventional Radiologist — May 12, 2026
