Fractures of the posterolateral maxillary sinus: a masticator space blowout injury?

BACKGROUND AND PURPOSE: Segmental, depressed fractures of the posterolateral maxillary sinus may occur as a result of trauma to the masticator space, previously described in association with mandibular fractures. The authors hypothesize that the fracture is due to a transient increase in pressure in the masticator space (blow out) and therefore should be seen in association with other regional fractures. MATERIALS AND METHODS: Injuries of the masticator space were retrospectively identified by searching the imaging database from January 2014 to November 2014 for keywords that would identify regional trauma. The images were reviewed for segmental depressed fractures in the posterolateral aspect of the maxillary sinus accompanied by herniation of a variable amount of masticator space fat and/or muscle into the adjacent sinus. Three neuroradiologists reviewed the images and agreed by consensus on the presence or absence of a masticator space blowout fracture. RESULTS: Forty-three zygomaticomaxillary complex (ZMC) fractures, 89 mandibular fractures, and 49 isolated zygomatic arch fractures were identified. While all of the ZMC fractures had a maxillary component, 3 of 43 (7.0 %) additional fractures met our fracture definition. Five of 89 (5.6 %) of the mandibular fractures and 6 of 49 (12.2 %) zygomatic arch fractures had an associated posterolateral maxillary fracture. CONCLUSIONS: Segmental depressed fracture of the posterolateral maxillary sinus is relatively common, occurring in conjunction with other regional injuries. The authors hypothesize that it is due to a transient increase in pressure in the masticator space and is a separate entity from other fractures of the region that may occur concurrently.

Clinical utility of multiplanar reformation in pulmonary CT angiography.

OBJECTIVE: The purpose of this study was to determine whether the view used, multiplanar or axial, for image interpretation at pulmonary CT angiography for suspected acute pulmonary embolism alters the diagnostic confidence, accuracy, and interpretation time of cardiothoracic radiology specialists and radiology residents. MATERIALS AND METHODS: Patients who underwent 50 consecutive pulmonary 64-MDCT angiographic examinations formed the study group (18 men, 32 women; mean age, 53 years; range, 19-93 years). Three blinded cardiothoracic faculty radiologists and three blinded radiology residents reviewed each case independently initially using only axial display mode and later using multiplanar reformation (MPR) in any x-, y-, or z-axis. The presence of pulmonary embolism in the main through subsegmental pulmonary arteries was scored on a 5-point scale; diagnostic confidence for the overall examination was scored on a 3-point scale; and interpretation time was recorded. A surrogate reference standard consisted of either faculty agreement or, in cases of disagreement, adjudication by another, senior faculty member. Statistical analysis included the Kendall coefficient (W), receiver operating characteristics curves, and a univariate repeated measures model. RESULTS: Interobserver agreement between specialists on the diagnosis of pulmonary embolism was good for axial viewing (W=0.72) and for MPR viewing (W=0.79). Interobserver agreement between residents was good for axial viewing (W=0.62) and for MPR viewing (W=0.70). Reader confidence improved among all readers with MPR viewing, but the difference did not reach statistical significance. Interpretation time with MPR was significantly longer for two of the three specialists and significantly shorter for two of the three residents. CONCLUSION: Use of MPR for viewing increased the reader agreement and interpretation time of cardiothoracic specialists but increased reader agreement between residents and might have decreased interpretation time. All readers had a trend toward increased confidence.