From the Guidelines
To rule out a sinus infection, I would recommend ordering a CT scan of the paranasal sinuses without contrast. This is based on the most recent and highest quality study, which suggests that CT is the gold standard for imaging evaluation of sinusitis, allowing for accurate depiction of sinus anatomy, soft-tissue changes, and potential associated complications 1. The study highlights the importance of CT in evaluating patients with sinonasal disease, including acute rhinosinusitis, chronic rhinosinusitis, and suspected orbital and intracranial complications.
Some key points to consider when ordering a CT scan for sinus infection include:
- CT provides detailed depiction of bony anatomy, which is essential for surgical planning 1
- CT can accurately demonstrate the presence of sinonasal disease, bony erosions, and anatomic variants 1
- MRI may be used as an alternative, particularly for evaluating soft tissue extension of tumor and identifying clinically suspected intracranial and intraorbital complications, but it is not as effective as CT in evaluating bony anatomy 1
- Radiography is limited in the evaluation of persistent sinusitis due to low sensitivity and specificity for sinus disease compared to CT 1
In terms of specific indications for CT versus MRI, the evidence suggests that:
- CT without contrast is indicated for recurrent acute sinusitis, chronic sinusitis, preoperative evaluation for sinus surgery, and nasal polyposis 1
- CT with contrast may be used to evaluate complications of sinusitis, such as periorbital edema and subperiosteal abscess, as well as sinonasal tumor 1
- MRI with contrast may be used to evaluate skull base dehiscence, unilateral sinonasal opacification, and sinonasal process with cranial extension, but it is not as effective as CT in evaluating bony anatomy 1
From the Research
Imaging for Spinal Infections
The provided studies focus on spinal infections, their diagnosis, and management. To determine the best scan to order for ruling out a sinus infection, we must first note that none of the studies directly address sinus infections. Instead, they discuss spinal infections and the role of imaging in their diagnosis.
Relevant Imaging Modalities
- Magnetic Resonance Imaging (MRI) is highlighted in several studies 2, 3, 4, 5, 6 as a powerful diagnostic tool for evaluating spinal infections.
- Computed Tomography (CT) is also mentioned 5 as a valuable method for evaluating structures potentially involved in spinal infection.
Diagnosis of Spinal Infections
- MRI findings such as vertebral endplate destruction, bone marrow and disk signal abnormalities, and paravertebral or epidural abscesses are indicative of spinal infection 2, 4.
- The presence of paraspinal or epidural inflammation, disk enhancement, and hyperintensity or fluid-equivalent disk signal intensity on T2-weighted MR images are criteria with good to excellent sensitivity for diagnosing disk infections 4.
Sinus Infection Diagnosis
Since the provided studies do not directly address sinus infections, there is no specific evidence to recommend a particular scan for ruling out a sinus infection. Typically, diagnosis of sinus infections involves clinical evaluation and may include imaging studies such as CT scans of the sinuses, but this information is not covered in the provided studies.