Occult neurovascular injury, carotid-cavernous fistula, or carotid transection can occur with severe facial fractures [62,63]. A penetration trajectory, vessel wall hematoma, infiltration of perivascular fat, or foreign bodies <5 mm from a vessel wall should raise suspicion of vascular injury requiring vascular imaging [64,65]. CT angiography (CTA) has been recommended over digital subtraction angiography for initial vascular evaluation because of its short acquisition time and low complication rate [21,29]. CTA detects almost all clinically relevant blunt cervical arterial injuries [29,66]. As stated above, BCVI, although uncommon in maxillofacial trauma, carries significant morbidity and mortality if not identified and treated early. Therefore, the exclusion of these injuries is necessary in the correct clinical context. Although MR angiography (MRA) is inferior to conventional arteriography, it is considered equivalent to CTA in BCVI. Similar to CTA, MRA does distinguish almost all clinically significant cervical arterial injuries [29,66]. However, MRA without IV contrast in the neck may be limited because of artifacts and limited resolution. Subtle vascular injuries such as wall irregularity and thickening and mild luminal irregularity can be difficult to detect [67]. Also, MRA with or without IV contrast is time-consuming, making it challenging to use in an acute trauma setting. Some debate exists as to whether CTA is superior to MRA in BCVI. One study found CTA to be superior [68], whereas another found them to be equivalent [29,69]. Virtual arteriograms can be created without IV contrast using time-of-flight or phase-contrast sequences. Nevertheless, pseudoaneurysms or subtle stenoses are more easily detected by administering contrast intravenously using 3-D time-of-flight imaging.
Imaging of Facial Trauma Following Primary Survey. Occult neurovascular injury, carotid-cavernous fistula, or carotid transection can occur with severe facial fractures [62,63]. A penetration trajectory, vessel wall hematoma, infiltration of perivascular fat, or foreign bodies <5 mm from a vessel wall should raise suspicion of vascular injury requiring vascular imaging [64,65]. CT angiography (CTA) has been recommended over digital subtraction angiography for initial vascular evaluation because of its short acquisition time and low complication rate [21,29]. CTA detects almost all clinically relevant blunt cervical arterial injuries [29,66]. As stated above, BCVI, although uncommon in maxillofacial trauma, carries significant morbidity and mortality if not identified and treated early. Therefore, the exclusion of these injuries is necessary in the correct clinical context. Although MR angiography (MRA) is inferior to conventional arteriography, it is considered equivalent to CTA in BCVI. Similar to CTA, MRA does distinguish almost all clinically significant cervical arterial injuries [29,66]. However, MRA without IV contrast in the neck may be limited because of artifacts and limited resolution. Subtle vascular injuries such as wall irregularity and thickening and mild luminal irregularity can be difficult to detect [67]. Also, MRA with or without IV contrast is time-consuming, making it challenging to use in an acute trauma setting. Some debate exists as to whether CTA is superior to MRA in BCVI. One study found CTA to be superior [68], whereas another found them to be equivalent [29,69]. Virtual arteriograms can be created without IV contrast using time-of-flight or phase-contrast sequences. Nevertheless, pseudoaneurysms or subtle stenoses are more easily detected by administering contrast intravenously using 3-D time-of-flight imaging.