CT scan of the lumbosacral spine: what it shows, preparation, cost, photo

What does a CT scan of the lumbosacral spine show?
CT with contrast
Indications
Contraindications
Preparing for the examination
How is the procedure performed?
Decoding the results
How often can you do it

CT scan of the lumbosacral spine is a modern, high-tech, informative and non-invasive method of examining the spinal column, which allows you to visualize the structure of the vertebrae, intervertebral discs, ligaments and other soft tissues surrounding the spine.
Computed tomography of the spine allows you to obtain black-and-white images that represent layer-by-layer sections of the human body. Dark and light areas of the images represent shadows of organs and tissues that have different abilities to block X-rays. The higher the ability of a tissue to absorb x-rays, the lighter the area in the image corresponding to that tissue will be. For example, bone tissue appears light, almost white in photographs due to its high ability to absorb X-rays.

During one examination, from 100 to 300 images can be obtained, depending on the thickness of the sections. The thickness of the sections is set manually by the doctor using the tomograph settings and depends on the purpose of the examination. All this makes it possible to identify even small tumors and notice pathological changes in tissues at the earliest stages of disease development.

What does a computed tomography scan of the lumbosacral spine show?

The following types of disorders can be identified in the images obtained during the examination::

congenital features of the development of the spine: vertebral defects, narrow spinal canal;
primary tumors and metastases;
osteochondrosis;
disc herniation;
inflammatory processes localized in the vertebrae and soft tissues surrounding the spine;
changes in the structure of the spinal canal, its stenosis (narrowing) or deformation;
changes in the spine, characteristic of a number of diseases, such as rheumatoid arthritis or ankylosing spondylitis;
hemorrhage in the spinal cord due to arteriovenous malformation;
fractures or displacement of the vertebrae;
consequences of injuries and surgical interventions.

Curvature of the spine (kyphosis) on CT

Externally, kyphosis manifests itself in poor posture and changes in the curvature of the spinal column. But this is not only an aesthetic defect. Stooping (increased bending towards the back) indicates an incorrect position of the vertebrae in relation to each other.

Most often, kyphosis affects the thoracic spine. Over time, this leads to displacement of other organs (for example, the diaphragm), wedge-shaped deformities of the vertebrae occur, and intervertebral discs become thinner.

There are 3 stages of kyphosis. And if at the first stage the curvature of the spine manifests itself in stooping, increased fatigue of the spine with muscle weakness, then at the third stage there are malfunctions in the functioning of the internal organs (atrophy of the intercostal muscles, disturbances in the functioning of the lungs).

Spinal curvature is detected by visual examination, but hardware-based radiological diagnostics is necessary to determine the degree of displacement and associated deformities. If surgical treatment is indicated for a patient with kyphosis, it is recommended to do a CT scan of the spine before surgery, since this is the most precise examination method. On tomograms, the neurosurgeon will see not only the osteochondral components, but also the vessels, since in order not to damage them during surgery, it is important to know their location.

CT scan of the lumbar spine with contrast

Computed tomography is the best method for examining bones. The vertebrae are perfectly visualized during the examination without the use of radiopaque agents.

In order to obtain clear images of intervertebral discs, vessels, ligaments and other soft tissues of the lumbosacral region, as well as various neoplasms (cancer, metastases), it is necessary to use special iodine-based contrast compounds.

Drugs for CT scanning of the lumbosacral spine can be administered in two ways:

once in a bolus: the drug is administered intravenously by injection before the start of the procedure or during it, if necessary;
bolus: the drug is injected into the blood at a constant rate throughout the entire examination procedure using a special automatic dispenser.

The following symptoms may occur in response to the administration of a contrast agent::

pain at the injection site;
flushes of heat or heat in the body;
sour or metallic taste in the mouth.

If these reactions occur, the examination can be continued.

The development of intolerance to the contrast drug is indicated by:

swelling of the face, ears;
difficulty breathing due to swelling of the larynx;
sore throat;
nausea and vomiting;
itchy skin;
hives
bronchospasm;
drop in blood pressure.

If any of the above symptoms appear, you should immediately seek help from medical staff.

The risk of developing an allergic reaction is increased in individuals with intolerance to drugs containing iodine, seafood, as well as in patients suffering from bronchial asthma.

How is a CT scan of the spine performed?

Depending on the equipment used, linear and spiral CT are distinguished. The first is done on a tomograph, which simultaneously moves sensors and X-ray emitters in opposite directions. The area in the center of the scanning system is in focus. Structures located above or below the main axis are blurred. For linear CT scans of the spine, the minimum slice thickness is 3 cm.

Spiral computed tomography involves rotating the scanning system (tubes + detectors) around the table with the patient. At the same time, the conveyor moves in a horizontal plane inside the ring of the apparatus.

Modern tomographs take 2 or more (8, 16, 64) images per full revolution. The thickness of the scanned section is from 0.2 cm. This study of the spine is called multislice CT.

To improve the quality of photographs and prevent artifacts, the patient must remain motionless throughout the session. To do this, the body and limbs are fixed using special rollers and fasteners.

Computed tomography of the spine

After preparing the patient for the procedure, the doctor and laboratory assistant move to the next room where the monitors are located. Communication with the patient is maintained through a microphone.

The duration of the spine examination depends on how the CT scan is performed. The native procedure takes no more than 10 minutes. If it is necessary to administer a contrast solution, the scanning duration increases. After a series of routine scans, the patient is given an injection of an iodine-containing drug. The substance fills the vascular bed in the area of interest, after which the session continues. A CT scan with contrast takes up to 20 minutes.

Detectors record information about the density of spinal structures and transmit the data for processing by a computer program. The monitor receives layer-by-layer images in an axial projection. Based on the photographs obtained, the sagittal and frontal planes of the area under consideration are completed. If necessary, the 3D image is reconstructed.

Indications for lumbar CT scan

A referral for examination can be obtained in the following cases:

abnormalities of the spine;
spinal deformity;
determination of bone tissue density (densitometry);
narrowing of the spinal canal;
acute and chronic spinal injuries;
oncological diseases: confirmation of changes detected on x-rays, determination of the size, location of the primary tumor and metastases, stage of the tumor process;
chronic pain in the spine that does not go away after a standard course of treatment;
herniated intervertebral discs;
tumors of the spine and surrounding soft tissues, metastases of tumors to the spine from other organs;
tuberculous spondylitis (inflammation of the vertebrae);
osteomyelitis;
malformations (vascular anomalies);
preparation for spinal surgery;
monitoring the condition of the spine after treatment (radiation or chemotherapy).

Contraindications for examination

The examination is not carried out in the following cases:

pregnancy at any stage;
patient weight that exceeds the maximum permissible load on the tomograph table (about 120 kg).

A CT scan of the lumbosacral spine is performed with caution and only if there are serious indications.:

children under 12 years old;
nursing women (milk becomes unsuitable for feeding the baby for some time);
patients with renal failure;
with multiple myeloma.

Contraindications for the administration of a radiocontrast agent:

pregnancy and lactation;
renal and liver failure;
diabetes;
intolerance to iodine-containing contrast agents.

How should you prepare for a CT scan of the spine?

A CT scan without contrast can be done urgently, on the day of visiting the clinic. For your appointment you should take:

passport;
compulsory medical insurance policy;
direction;
results of earlier studies.

The patient discusses possible contraindications with the specialist, warns about concomitant diseases and medications taken.

A woman should tell her doctor about her suspected or actual pregnancy. In some cases, additional examination is carried out to clarify the condition.

Computed tomography of the spine with contrast requires preparation. Patients take a creatinine test. A high level of the latter in the blood is a sign of renal failure and serves as a contraindication to the procedure.

Patients with diabetes mellitus taking Metformin visit an endocrinologist. The drug must be discontinued 3 days before a contrast-enhanced CT scan.

Breastfeeding women should take care of nutrition for the baby. After the procedure, you need to express your breasts for 6-12 hours, do not use milk for feeding.

Scoliosis of the spine on CT images

Metal piercings and jewelry can negatively affect image quality. Before the procedure, you should remove outer clothing and accessories.

How is a lumbosacral CT scan performed?

It is necessary to ensure that there are no metal fasteners or trim elements on clothing in the lumbar area or on the stomach. Any metal objects leave shadows on the images, which significantly reduces the information content of the examination. The patient may be asked to change into a special robe with clasps or a shirt. When going for an examination, it is advisable to choose loose clothing that will be comfortable for you to lie still for a long time. Any voluntary or involuntary movements can spoil the images, so the patient may be secured on the tomograph table with straps.

To administer a bolus of contrast drug into a vein in the patient’s arm, a special catheter is placed, which is connected to a dispenser using a thin tube. The dispenser is designed to supply the drug into the patient’s blood at a given speed for a long time.

A single contrast agent can be administered immediately before the start of the procedure or during the examination, after a series of native images has been taken.

The table together with the patient is moved into the tomograph, the medical staff leaves the room in which the tomograph is located to avoid radiation exposure. The entire time the examination is ongoing, the medical staff monitors the patient’s condition through a special window that is impenetrable to X-ray radiation. You can contact the nurse using two-way voice communication.

When all the images have been taken, the doctor checks the quality of the resulting images. If the images are clear, without distortion, then the examination is considered completed, the patient is released to change clothes and wait for a doctor’s report.

How the research works

During the scan, the patient is placed in the tomograph tunnel. Before doing this, he needs to remove all metal objects. When the tomograph ring rotates around the extendable table, numerous layer-by-layer images are created. To ensure that the images are not distorted, you must remain still during the procedure. The procedure is absolutely painless and lasts from 5–10 minutes to half an hour (for examination with contrast).

After the scanning is completed, the resulting images are processed on a computer, deciphered by specialists and given to the patient along with a medical report.

Decoding the results obtained

In order to make a diagnosis using computed tomography data, it is necessary to describe the pathological changes that are present in the obtained images. A radiologist or radiation diagnostics doctor is engaged in decoding. Any information about previous examinations and treatment that the patient can provide can help the doctor. After decoding, the patient receives photographs on digital media or printed on film, as well as a doctor’s report certified by signature and seal.

Features of CT with a contrast enhancer

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To clarify some changes, such as formations, for example, in the lumbosacral region, radiocontrast agents are used. The basis of such drugs is iodine.

Before carrying out a procedure using radiocontrast agents, a test for the body's sensitivity to iodine-containing solutions must be performed.

The presence of an allergic reaction is a contraindication to the procedure. A sharp deterioration in the patient's condition due to the administration of a contrast agent is the basis for interrupting the diagnosis.

A radiocontrast agent is administered to the patient intravenously. The images are deciphered by a qualified specialist - a radiologist - at the end of the scanning procedure.

How often can a CT scan of the lumbar spine be done?

During the examination, the patient's body is exposed to x-ray radiation, which can cause a number of adverse changes in the human body. In this regard, for computed tomography, restrictions have been introduced on the volume of one examination and the frequency of procedures.

The optimal interval between CT examinations is 12 months, regardless of whether the same area of the patient’s body will be examined or some other area. If there are serious indications, a re-examination can be performed no earlier than 6 months after the first.

Advantages and features of CT

In terms of information content, CT is not inferior to MRI. Moreover, computed tomography is preferable for assessing the condition of bone tissue. Also, CT becomes the method of choice if the patient has such contraindications to MRI, such as the presence of metal foreign bodies, implants, etc. in the body.

X-ray and ultrasound compared to computed tomography are less accurate and not always reliable. In addition, the radiation dose from a CT scan is significantly lower than from a traditional X-ray examination.