From the Guidelines
A thoracic MRI is ordered after a motor vehicle accident to evaluate for potential spinal cord injury, disc herniation, vertebral fractures, ligamentous injuries, and soft tissue damage that may not be visible on other imaging modalities. This advanced imaging technique provides detailed visualization of the thoracic spine's neural elements, intervertebral discs, ligaments, and surrounding soft tissues without radiation exposure. It is particularly valuable when patients present with thoracic pain, neurological deficits, or when there is suspicion of injury despite normal radiographs or CT scans. MRI can detect subtle injuries like cord contusion, small disc herniations, or ligamentous injuries that might be missed on other imaging 1. The timing of the MRI depends on the clinical presentation - it may be ordered emergently for patients with neurological deficits or can be delayed for those with stable symptoms without neurological compromise. Some key points to consider when ordering a thoracic MRI after a motor vehicle accident include:
- The presence of thoracic pain or neurological deficits, which may indicate spinal cord injury or other thoracic spine injuries 1
- The mechanism of injury, with high-energy mechanisms such as motor vehicle accidents increasing the risk of thoracic spine injury 1
- The patient's age and overall health status, with older patients or those with underlying medical conditions potentially being at higher risk for complications from thoracic spine injuries 1
- The results of other imaging studies, such as radiographs or CT scans, which may be used to guide the decision to order a thoracic MRI 1
- The potential benefits and risks of thoracic MRI, including the lack of radiation exposure and the potential for detecting subtle injuries that may be missed on other imaging modalities 1 It is also important to note that thoracic MRI is not without risks and limitations, and alternative imaging modalities such as CT or radiographs may be necessary in certain cases, such as patients with certain implanted devices or those who cannot remain still during the examination 1. The detailed information provided by thoracic MRI helps guide appropriate treatment decisions, whether conservative management or surgical intervention is needed.
From the Research
Clinical Rationale for Thoracic MRI after Motor Vehicle Accident
The clinical rationale for ordering a thoracic MRI after a motor vehicle accident is based on several factors, including:
- The risk of severe thoracic injury, which can be increased by specific vehicle contact points, such as the steering wheel, door panel, armrest, and seat 2
- The importance of identifying posterior ligamentous complex (PLC) injuries, which can be associated with severe vertebral body destruction and traumatic kyphosis 3
- The need to assess the risk of thoracic aorta injury, which can be higher for occupants seated on the side closest to the impact, and for those involved in side-impact crashes 4
Diagnostic Considerations
When considering a thoracic MRI after a motor vehicle accident, the following diagnostic considerations are important:
- The use of MRI to examine soft tissue injury and to evaluate the integrity of the posterior complex 5
- The ability of MRI to reveal macrostructural evidence of primary intramedullary damage, such as hemorrhage, edema, and post-traumatic cystic cavities 6
- The potential for MRI to identify occult fractures and to modify treatment decision making 5
Imaging Findings
Imaging findings that may be relevant to the clinical rationale for thoracic MRI after a motor vehicle accident include:
- Loss of height of the fracture, local kyphosis, and supraspinous distance, which can be significantly higher in patients with PLC injuries 3
- The presence of hemorrhage, edema, and post-traumatic cystic cavities, which can indicate primary intramedullary damage 6
- The identification of vertebral contusions and occult fractures, which can modify treatment decision making 5