From the FDA Drug Label
The decision to employ contrast enhancement, which may be associated with risk and increased radiation exposure, should be based upon a careful evaluation of clinical, other radiological, and unenhanced CT findings. The FDA drug label does not answer the question.
From the Research
For evaluation of zone 2 neck lacerations, CT with contrast is recommended over non-contrast CT. Contrast-enhanced CT allows better visualization of vascular structures, which is crucial since zone 2 of the neck contains critical vascular structures including the carotid and vertebral arteries and jugular veins. The contrast medium highlights blood vessels, making it easier to identify vascular injuries such as arterial dissections, pseudoaneurysms, or active bleeding that might not be visible on non-contrast studies. Additionally, contrast enhancement helps differentiate between vascular and non-vascular structures, providing clearer delineation of the extent of injury to surrounding soft tissues, muscles, and aerodigestive tract. This information is essential for determining whether surgical exploration is necessary.
The typical protocol uses intravenous iodinated contrast media administered at a rate of 3-5 mL/second with imaging timed to the arterial and venous phases. However, in patients with contraindications to iodinated contrast (such as severe renal impairment or allergy), alternative imaging modalities like Doppler ultrasound or MRI may be considered, though these are generally less optimal for acute trauma evaluation. Recent studies, such as 1, have shown that spectral computed tomography angiography using a gadolinium-based contrast agent can be a feasible alternative for imaging of pathologies of the aorta, and by extension, potentially for zone 2 neck lacerations, especially when iodinated contrast is contraindicated.
Some key points to consider:
- The use of contrast media is essential for enhancing the diagnostic capabilities of imaging studies, such as computed tomography, as noted in 2.
- Gadolinium-based contrast agents can be used as an alternative to iodine-based contrast agents in certain cases, as shown in 3 and 1.
- Dual-energy computed tomography (DECT) can improve the imaging of gadolinium-based contrast agents, as demonstrated in 4.
- Physical examination alone may not be sufficient for evaluating penetrating zone 2 neck injuries, as highlighted in 5, emphasizing the importance of imaging studies like CT with contrast.
Given the importance of accurately assessing vascular injuries in zone 2 neck lacerations and the potential risks associated with contrast media, the use of CT with contrast is prioritized for its ability to provide detailed images of vascular structures and surrounding tissues, thereby guiding appropriate management and reducing morbidity and mortality.