Is a 1.5 Tesla (Magnetic Resonance Imaging) MRI in an upright position sufficient to evaluate for craniocervical instability?

From the Guidelines

A 1.5 Tesla upright MRI is generally sufficient to evaluate for craniocervical instability (CCI) due to its ability to visualize the craniovertebral junction in a weight-bearing position, which is crucial for assessing dynamic instability. This is supported by the fact that MRI is preferred to CT myelography for assessing neurologic injury in the setting of spine trauma, as stated in the 2019 study by the American College of Radiology 1. The 1.5 Tesla magnetic field strength provides adequate image quality to evaluate the ligaments, bone structures, and neural tissues in the craniocervical region.

Key Considerations

• For optimal assessment, the imaging protocol should include flexion and extension views to capture dynamic instability, as this can reveal abnormal movement or misalignment that might not be apparent when lying down.
• While higher field strength MRIs (3T) may offer slightly better resolution, the ability to image in the upright position is more critical for diagnosing CCI than field strength alone, as it better reproduces the symptoms and can demonstrate pathological movement that conventional supine MRIs might miss.
• It's also important to consider that the correlation of MRI findings with acknowledged standards is often poor, as seen in a series of 11 surgical patients where MRI detected all injuries but included two false positive longitudinal ligament ruptures 1.
• Additionally, the cost of routinely obtaining MRI scans is likely to remain high, and in one series of 479 obtunded patients, it would have added $700,000 without one single additional injury being detected 1.

Clinical Implications

• If CCI is strongly suspected but initial imaging is negative, additional dynamic imaging or other diagnostic tests may still be warranted.
• The use of MRI in evaluating CCI should be guided by clinical judgment and consideration of the patient's specific condition, as well as the potential risks and benefits of imaging.
• The 2019 study by the American College of Radiology 1 provides guidance on the appropriateness of imaging modalities in suspected spine trauma, including the use of MRI in evaluating CCI.

From the Research

Evaluation of Craniocervical Instability using Upright MRI 1.5 Tesla

• The effectiveness of an upright MRI 1.5 Tesla in evaluating craniocervical instability can be assessed by considering various studies that have investigated the use of MRI in diagnosing craniocervical junction injuries and instability 2, 3, 4, 5, 6.
• A study published in 2012 found that MRI can be used to diagnose craniocervical dislocations and identify ligamentous injuries that characterize these injuries 2.
• Another study published in 2023 established reference ranges for four diagnostic measures of craniocervical instability using upright dynamic MRI, highlighting the potential of this modality in evaluating craniocervical stability 3.
• A 2021 study emphasized the importance of MRI in evaluating occipitoatlantal instability, particularly in cases where CT scans may not clearly show evidence of instability 4.
• The use of MRI in diagnosing craniocervical dissociation was also highlighted in a 2010 study, which found that MRI evaluation was crucial in identifying injuries that may not be apparent on initial cervical spine imaging 5.
• A 2024 study analyzed the variance of normative supine and upright imaging in a healthy population, providing baseline ranges and variability of radiographic measurements that can be used to diagnose craniocervical instability 6.

Key Findings

• Upright MRI 1.5 Tesla can be used to evaluate craniocervical instability, particularly in cases where CT scans may not provide sufficient information 2, 4.
• The modality can help identify ligamentous injuries and characterize craniocervical junction injuries 2, 3.
• Reference ranges for diagnostic measures of craniocervical instability have been established using upright dynamic MRI, providing a basis for evaluating craniocervical stability 3.
• MRI evaluation is crucial in identifying injuries that may not be apparent on initial cervical spine imaging, and can help guide surgical management and treatment 4, 5.
• Understanding normal variance in cervical measurements is essential for accurate diagnosis of craniocervical instability, and upright MRI 1.5 Tesla can provide valuable information in this regard 6.