Diagnostic imaging of maxillofacial infections

Emergency imaging assessment of deep neck space infections

Deep neck space infection may lead to severe and potentially life-threatening complications, such as airway obstruction, mediastinitis, septic embolization, dural sinus thrombosis, and intracranial abscess. The clinical presentation is widely variable, and often early symptoms do not reflect the disease severity. The complication risk depends on the extent and anatomical site: diseases that transgress fascial boundaries and spread along vertically oriented spaces (parapharyngeal, retropharyngeal, and paravertebral space) have a higher risk of complications and require a more aggressive treatment compared with those confined within a nonvertically oriented space (peritonsillar, sublingual, submandibular, parotid, and masticator space). Imaging has 5 crucial roles: (1) confirm the suspected clinical diagnosis, (2) define the precise extent of the disease, (3) identify complications, (4) distinguish between drainable abscesses and cellulitis, and (5) monitor deep neck space infection progression. Ultrasonography is the gold standard to differentiate abscesses from cellulitis, for the diagnosis of lymphadenitis. and to identify internal jugular thrombophlebitis in the infrahyoid neck. However, field-of-view limitation and poor anatomical information confine the use of ultrasonography to the evaluation of superficial lesions and to image-guided aspiration or drainage. Computed tomography (CT) combines fast image acquisition and precise anatomical information without field-of-view limitations. For these reasons, it is the most reliable technique for the evaluation of deep and multicompartment lesions and for the identification of mediastinal and intracranial complications. Contrast agent administration enhances the capability to differentiate fluid collections from cellulitis and allows the detection of vascular complications. Magnetic resonance imaging is more time-consuming than CT, limiting its use to selected indications. It is the technique of choice for assessing the epidural space involvement in pre- and paravertebral space infections and complements CT in the evaluation of the infections reaching the skull base.

Comparison of preoperative computed tomography and surgical findings in maxillofacial infections

PURPOSE

To examine the accuracy of computed tomography (CT) in predicting the presence of surgically confirmed abscess in patients presenting with deep maxillofacial infections (DMIs).

MATERIALS AND METHODS

The medical records of 36 patients with clinically suspected DMI were reviewed. All patients underwent preoperative CT scan to determine whether abscess or cellulitis was present. The operative reports of all patients were compared with their preoperative CT scan findings.

RESULTS

Of 36 patients, 30 had abscess predicted by preoperative CT scan. The positive predictive value for DMI based on CT findings interpreted by an oral surgeon and confirmed as an abscess at operation was 90%, whereas the negative predictive value was 33%. When findings were interpreted by a radiologist, the positive predictive value was 94.1% whereas the negative predictive value was 26.3%. Thirty patients had abscess predicted by preoperative CT scan when interpreted by an oral surgeon, whereas seventeen had abscess predicted by a radiologist. At operation, 3 of 30 patients had cellulitis whereas 27 had abscess, for a false-positive rate of 60% and false-negative rate of 12.9%. On the basis of preoperative radiography, 1 of 17 patients had cellulitis whereas 16 had abscess, for a false-positive rate of 16.7% and a false-negative rate of 46.7%. The agreement between CT and operative findings in predicting abscess by an oral surgeon was 80.6% and by a radiologist was 58.3%.

CONCLUSION

CT yielded high sensitivity for the detection of DMI abscess but poor specificity, likely because of the paucity of cellulitis.

Rhinosinusitis: review from a dental perspective

Patients often present to their dental providers with reports of posterior maxillary pain. The etiology of their symptoms may be either an acute or chronic situation, and the examining dentist's primary focus is usually to rule out dental pathosis. Rhinosinusitis should be an important consideration on the list of differential diagnoses when evaluating patients with posterior maxillary pain. The American Academy of Otolaryngology standardized the terminology for paranasal sinus infections in 1996 and offered guidelines for evaluation and treatment of sinusitis. This article highlights these guidelines for diagnosing and treating patients with rhinosinusitis. It also includes a review of sinus anatomy and of the special considerations for iatrogenic sinus exposure as well. Dental providers who understand the relationship between the maxillary sinus and the oral structures are better prepared to arrive at an accurate diagnosis. The astute dental provider will ensure a rapid and positive outcome for this group of patients with rhinosinusitis.