Vertebral spine CT scan
Vertebral spine CT scan at the moment is important in the diagnosis of diseases of the lumbar spine, such as disc herniation in osteochondrosis. Vertebral spine CT scan compared with other radiological methods of study has a number of advantages - the method is noninvasive, provides clear visualization of bone structures, discs, ligaments and soft tissues.
Vertebral spine CT scan demonstrated direct signs of disc herniation and other elements that narrows the spinal canal and intervertebral foramen, allows a clear identify their location, size and relationships with the surrounding anatomical structures.
A CT scan of the spine may be used to check the spine for a herniated disk, stenosis, scoliosis, traumatic injuries, tumors, congenital structural problems such as spina bifida, blood vessel problems, or infections.
Analysis of the results of computed tomography (CT) of the spine is very important multiplanar reconstruction, through which can be interpreted not only received axial, but also sagittal, frontal and oblique planes.
For flattened lumbar lordosis and reduce pain vertebral spine CT scan performed in the supine position with a roll under the knees. The angle of the frame, "Gentri" is selected by the CT scan of the spine in a lateral plane while observed parallelism of the scanning plane with the plane of the intervertebral disc.
Depending on the number of investigated vertebrae can select several areas tomography. Therefore, in the zone of interest by scanning the spine get more mobile segments. However, changing the angle of inclination "Gentri" for each individual segment of the spine is not always observed. Therefore, by setting the angle of inclination of the most spine-segment changes on the basis of X-ray, tomography, based on clinical data, in the future, it does not change. This is particularly important in the caudal direction hernia and its "sequestration".
To perform computer-tomography (CT) of the spine usually use tomographic thickness of 3 mm, 3 mm pitch tomography. For the study of the vertebral segment is sufficient 8-12 CT scan. In all cases, necessarily performed multiplanar reconstruction in the sagittal and frontal planes, and if necessary - in the oblique projections. Line reconstruction carried through as acting in the axial plane of the section of disc herniation. computer-tomographic study (CT) of the spine usually use thick tomographic slice 3 mm, pitch of 3 mm. tomographybased To study one spinal segment sufficient 8-12 computer tomograms. In all cases, necessarily performed multiplanar reconstruction in sagittal and frontal planes, and if necessary in oblique projections. Line reconstruction is performed using maximum protruding in the axial plane, the site of disc herniation.
Indications for computed tomography (CT) of the spine are:
- assessment of intervertebral disks
- the discrepancy between clinical data and preliminary x-ray studies
- presence of radiculopathy or myelopathy syndrome
- identification of malformations of osteoarticular apparatus, tumors, traumatic changes, inflammatory lesions of the spine
Vertebral spine CT scan, compared with the traditional spondilography, allows a more detailed study of the anatomical structure of the spine. The spinal cord, lying in the spinal canal occupies the space between the first cervical and the upper edge of the second lumbar vertebra. It is a continuation of the cauda equina, the end thread which is at the level of the second coccygeal vertebra is attached to the dura mater.
From the spinal cord come out motor roots and come back the sensitive roots. Anterior and posterior roots in the spinal canal converge, forming in the intervertebral foramen the spinal ganglia and in the future - spinal roots, that exit from the intervertebral canal are divided into anterior and posterior branches. Spinal roots located slightly above of the intervertebral disk, except L2 spinal root, leaving the dural sac high above the disk, and L3 spinal root, exiting under the disc. Normally maybe asymmetrical development of spinal roots, which differ in size and density.
The main area of roots lesion by deformations of the intervertebral disc is a dorsal division, where the posterior median and paramedian disc protrusion causing spinal roots tension at the base. Large paramedian herniation can cause tension of two homolateral roots of adjacent segments.
The narrowing of the spinal canal in the anteroposterior direction can be caused by its secondary stenosis, hypertrophy of the posterior longitudinal ligament, spondylolisthesis. To establish the spinal canal stenosis is necessary to measure the channel in the sagittal plane. Absolute stenosis is considered to be a decrease in the channel diameter of 10 mm or less. 10-15 mm in size corresponds to a partial stenosis. The thickness of the posterior longitudinal ligament normally should not exceed 2 mm, yellow ligament - 3 mm.
Densitometric parameters of the intervertebral disc are 75-100 units. Due to the low water content and high concentration of proteins density cancellous bone of the vertebral body is 170 ± 55 units. During osteosclerosis density can be increased to 500 units, and decrease to 0 units in osteoporosis. The most common disc deformation observed in the spine L4-L5, L5-S1 segments.
Venous plexus of the spinal canal is not always clearly differentiated. They are best visualized in the cervical and sacral regions on the anterior surface of the vertebral bodies. Certain difficulties in the study of intervertebral hernias are Batson venous plexus and vertebral veins.
Batson venous plexus are behind the vertebral body in the midline and connect with similar venous plexus of the upper and lower levels through the front internal vertebral veins, which can create some difficulties in the diagnosis Concrete venous plexus are behind the vertebral body in the midline and connect with similar venous plexus of the upper and lower levels through the front internal vertebral veins, which can create some difficulties in the diagnosis of disc warping. Furthermore, these often occur veins phlebolith.
The disc-radicular conflicts are possible in the area of the intervertebral foramen, the anterior wall of which forms the body of the overlying vertebra, upper - lower notch overlying vertebra, lower - the top incisure underlying vertebra, behind are adjacent lateral segment of the yellow ligament and the head of the superior articular process of the underlying vertebra.
The space occupied by the nerve roots in the intervertebral foramen is 10-50% of its area and located on the top floor of the hole, so the only cranial direction hernia can create nerve root compression. If degenerative changes of intervertebral foramen narrows to 5 mm in diameter (in combination with a hernia or traumatic factors) create conditions for the emergence of nerve root compression.
In the area of the intervertebral foramen are located trans vertebral veins that connect the anterior internal vertebral veins with external vertebral plexus and visualized more anteriorly from the spinal roots.
Vertebral spine CT scan provides more information about the state of the bone tissue, the presence of osteophytes, soft tissue calcification.