Total Spine MRI Study On Acute Spinal Trauma

【Objective】1. To study the values of magnetic resonance imaging for total spine applicated by MobiTrak technique in acute spinal trauma and spinal cord injury.2. To study the values of STIR sequence in total spine MRI for the diagnosis of acute trauma in multilevel vertebral bodies.3. To determine the incidence of non-contiguous multilevel vertebral body injury in association with acute spinal trauma as assessed by whole spine MRI.【Methods】1. Total spine MR images applicated by MobiTrak technique of 122 acute spinal injury patients were reviewed retrospectively. All total spine MR imagings obtained by using Philips Gyroscan Intera 1.5 T MR imaging system The MR images were obtained 2- 72hours after the patients' admission to the hospital. The standard protocol of total spine at least consisted of the sagittal T1-weighted (TR/TE=400/13 ms) and T2-weighted (TR/TE=3500/120 ms, echo train lengths of 8), fast spin echo sequences, The section thicknesses were 5 mm with a gap of 1 mm. On total spine MR images, we evaluated the presence of marrow contusion or fracture in multilevel vertebral bodies, ligaments' injury, traumatic disc herniation and spinal cord injury according to literatures.2. Three radiologists assessed 79 cases prospectively, which we collected in acute trauma of spine over a period of 3 years. All cases had T2-weighted,T1-weighted and STIR sagittal imagings of the whole spine. Compared the rate of detecting abnormal signal in suspected traumatic vertebral bodies in the images of STIR sequence with conventional T₂WI sequence, x² test was used for statistical analysis.3. We evaluated the non-contiguous injury in multilevel vertebral bodies on 79 total spinal MR imagings of STIR. Non-contiguous injuries are those separated by at least one normal intervening vertebra apart from the primary spinal traumatic site. The non-contiguous injury was evaluated with regard to the presence of marrow contusion, overt fracture. The incidence of secondary non-contiguous multilevel vertebral body injury (defined as either bone bruising, wedge compression fracture or burst fracture) was determined in association with acute spinal trauma as assessed by whole spine MRI.【Results】1. All 71 cases obtained clear images of total spine and spinal cord. Most patients had a combination of multiple levels and multiple types of secondary injury, which could be contiguous or non-contiguous, the secondary injury was commonly located in a different region of the spine to the primary injury. The majority of secondary injuries were located in the thoracic region. 75.4% of cases had a secondary injury level. Of these, bone bruises (microtrabecular bone injury) in 47.5% of spinal injury patients was the commonest.2. All 79 cases obtained clear images of total spine and spinal cord, In the images of STIR sequence, we discovered 227 vertebral bodies with abnormal signal were regarded as the result of acute trauma. At the same time, 189 vertebral bodies with abnormal signal were found in the images of convention T₂WI sequence. There were 77 traumatic vertebral bodies which had morphologic change in both the images of STIR sequence and convention T₂WI sequence. There were 38 vertebral bodies bone bruises which were not seen on conventional T₂WI sequence, Whereas these bone bruises were best appreciated on sagittal short tau inversion recovery MR sequences and seen at contiguous and non-contiguous levels in relation to the primary injury. There was significant difference between STIR sequence and convention T₂ W sequence on the rate of detecting the vertebral bodies with abnormal signal and normal size (x²=36.026, P＜0.001).3. Twenty-eight of 79 cases (35.4%%) showed non-contiguous marrow contusions (n=15) or overt fractures(n=13) on total spinal MRI of STIR sequence, Of these, bone bruises(microtrabecular bone injury) was the commonest in 53.5% of the secondary non-contiguous multilevel vertebral body injury. The distance (measured by the number of normal vertebrae) between the primary level and the secondary level ranged from one to 14 vertebrae【Conclusion】1. Magnetic resonance imaging of total spine applicated by MobiTrak technique is established as a vital imaging technique and can answer many of the questions. The clinician managing patients who have suffered trauma to the spine requires several questions answered from imaging studies. In the acute stage, a full assessment of the complete injury to the bony, ligamentous, disc and neural tissues will determine the stability of the injury and help decide the nature of clinical management, either conservative or surgical, and also help in determining the surgical approach.2. The values of MRI total spine combined with STIR technique was superior to convention T₂W sequence for the whole diagnosis of acute trauma in the multilevel vertebral bodies without morphologic change and showing the accurate location of vertebral injury. Combined with convention T₁WI and T₂WI sequence should be helpful as a important complementary sequence in the clinic application of acute spinal trauma。3. The 35.4% incidence of secondary non-contiguous multilevel vertebral body injury was determined in association with acute spinal trauma as assessed by whole spine MRI with STIR sequence. This level of incidence was higher than that has been described in previous studies based on radiographic evaluation of the whole spine. Whole spine MRI with STIR sequence in assessment for occult vertebral body injury enables increased confidence in the conservative or surgical management of patients with severe spinal trauma. We recommend that patients undergoing MRI for an injured segment of the spine are better assessed by MRI of the entire spine at the same time to exclude further injury.