Imaging examination of lumbar disc herniation

In the diagnosis of lumbar intervertebral disc herniation, in addition to the changes in the medical history and physical examination signs, an important diagnostic basis is the imaging examinatio.

Lumbar intervertebral disc herniation is more common in young and middle-aged people, and it is more common in people aged 20-50. For the diagnosis of trauma, degeneration of the intervertebral disc, and torn lumbar intervertebral disc herniation, in addition to the changes in the medical history and physical examination, an important diagnostic basis is the imaging examinatio.

Lumbar intervertebral disc herniation is more common in young and middle-aged people, and it is more common in people aged 20-50. A series of low back and leg pain symptoms occur due to trauma and intervertebral disc degeneration, tear, nucleus pulposus prolapse, compression of the spinal cord and nerve root.

L4-5 and L5-S1 are the most common sites of lumbar disc herniation, and other sites are rar.

Stenosis of the intervertebral space, which can be uniform or non-unifor.

The formation of osteophytes on the edge of the vertebral body, this disease has no special diagnostic significance, because osteophytes are more common in hypertrophic spondyliti.

Abnormal physiological curvature of the spine (lateral radiograph), or scoliosis (frontal radiograph.

The nucleus pulposus protrudes into the vertebral body: The nucleus pulposus protrudes into the cancellous bone of the upper and lower vertebral bodies through the damaged rupture of the cartilage disc, forming an indentation of the size of soybean and broad bean on the edge of the vertebral body, which is called Xu Mo's ( SCHMORL) nodule.

The application of CT to examine spinal and intraspinal lesions has been widely carried out in clinical practic.

Degeneration and bulging of lumbar intervertebral disc: Degeneration and degeneration of lumbar intervertebral disc can produce nitrogen gas, the so-called vacuum phenomenon, and the CT value is negativ.

2, lumbar disc herniation: divided into three type.

①Central type, refers to those located in the midline,

② Lateral type refers to those located in the spinal canal on both sides of the midline, and ③ Lateral type refers to those whose protruding center is located outside the spinal cana.

Direct Signs:

①The soft tissue shadow of the posterior edge of the lumbar intervertebral disc protruding into the spinal cana.

② Prominent lumbar discs may vary in size, shape or calcificatio.

③The density of free nucleus pulposus fragments in the epidural canal is higher than that of the dural sa.

Indirect Signs:

①The epidural fat space is displaced, narrowed or disappeared,

②The dural sac and nerve root are compressed and displace.

MRI can be said to be a major advancement in imagin.
It is unmatched by any previous inspection methods in non-invasive and non-radioactive damag.
Its image display of human tissue structure is more accurate and true than CT inspectio.
MRI examination is of great significance for the diagnosis of intervertebral disc herniatio.
Through the sagittal images of different levels and the transverse images of the involved intervertebral discs, the shape of the diseased intervertebral disc herniation and its relationship with the surrounding tissues such as the dural sac and nerve root can be observe.

The signals displayed on MRI images are generally divided into three types: high, medium, and low intensitie.
Usually, under T1-weighted conditions, cortical bone, ligament, cartilage endplate and annulus fibrosus are low signal intensity; vertebral body, spinous process and other cancellous bone rich in fatty tissue show moderate signal (due to the fact that it contains a lot of bone marrow tissue) ; The intervertebral disc is between the first tw.
Adipose tissue was the most intense signal, followed by spinal cord and cerebrospinal flui.
T2-weighted images showed more obvious intervertebral disc tissue lesions, and showed lower signal on T1-weighted images, but enhanced T2-weighted image.
Due to the strong and bright signal of T2-weighted cerebrospinal fluid, it is more clear when the disc herniation compresses the dural sa.

MRI examination can not only obtain three-dimensional images for diagnosis (the positive rate can reach more than 99%), but more importantly, this technology can be used to locate and distinguish "bulge", "protrusion" and "prolapse", which is beneficial to treatmen.
Method and choice of surger.

On T1WI, the intervertebral disc is polypoid or semicircular and protrudes into the spinal canal from the median or posterolateral side, and its signal intensity is the same as that of the degenerated intervertebral disc, and it forms with the epidural fat of high signal intensity and the dural sac of low signal intensity stark contras.
The cerebral fluid in the prominent and hyperintense dural sac contrasted clearly on T2W.

The MRI sagittal image is convenient for confirming and locating the nucleus pulposus fragments, which are located above or below the intervertebral spac.

Linear high signal can be seen up and down the herniated nucleus pulposus, which is caused by the slow blood flow caused by the compression of the epidural venous plexu.

Unenhanced CT is easy to confuse the combined nerve root or asymmetric nerve sheath with the nucleus pulposus herniated into the lateral recess, while MRI can clearly confirm the cerebrospinal fluid space around the nerve, so as to distinguish it from the herniated nucleus pulposu.

Intervertebral disc degeneration In normal intervertebral discs, the moisture content decreases and collagen fibers increase with ag.
MRI reflects that the intervertebral disc signal gradually weakens and is uneven, and the intervertebral space becomes smalle.
Early degeneration on T2WI shows that the nucleus pulposus signal gradually weaken.

The application of modern diagnostic techniques such as CT, CTM, and MRI provides a more objective basis for the diagnosis of lumbar disc herniatio.
However, it should not be overly relied on for its clinical significance, so as not to make the mistake of expanding the diagnosi.
X-ray and CT alone can not fully diagnose the intrinsic vertebral body by showing bone hyperplasia at the posterior edge of the vertebral body, herniation or bulging of the intervertebral dis.
Such as CTM and MRI found nerve root compression can not establish the diagnosi.
Imaging changes must be consistent with clinical symptoms in order to establish a diagnosi.
If there is lumbar disc herniation or bulging on imaging, but lack of corresponding clinical symptoms or signs, if blind surgery is performed, not only the curative effect is not good, but the pain of the patient can be increase.
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