Axial-loaded magnetic resonance imaging in the diagnosis of static disorders of the lumbar spine

Introduction The diagnosis of spinal statics disorders requires a study conducted both with and without axial load. Standard multislice computed tomography (MSCT) and magnetic resonance imaging (MRI) are limited to the examination of the patient in the supine position. Axial loading techniques have expanded the indications for the use of high-tech methods of radiological diagnosis in assessing the statics of the lumbar spine. Methods 124 patients underwent conventional radiographic examination of the lumbar spine in the frontal and lateral projections in a standing position and an MRI study before and during axial load. Radiography with functional tests was used for cases with displaced vertebras. The Pearson correlation coefficient was used to compare the data; the significance of the methods was evaluated using calculations of diagnostic performance indicators. Results An increase of the angle of lordosis was noted in tests with axial load (r = 0.93). Indicators of scoliotic deformity obtained with MRI with axial load corresponded to X-ray data (r = 0.89). The diagnostic efficiency of MRI with a dosed axial load was the following: Se = 91.7 %, Sp = 89.2 %, Ac = 90.6 %; the results of MRI in the upright position were slightly lower: Se = 89.2 %, Sp = 73.9 %, Ac = 83.3%. Spondylolisthesis was found in 11 patients. The instability data obtained by comparing MR studies before and during the axial load with radiography with functional tests revealed their almost complete correspondence (r = 0.88). Discussion Axial-loaded MRI can provide additional information on statics, which is necessary to assess the nature of pathological changes. MR techniques based on low-field tomographic systems are limited in the diagnosis of extended deformations. MRI with axial load is a method of choice, especially when dynamic monitoring is necessary, due to the absence of ionizing radiation. Axial loading of the spine in MSCT study seems promising.