Computed Tomography (CT) Scan

Computed Tomography Scan Nursing Diagnostic and Laboratory Tests - Responsibilities, Procedures, and Nursing Considerations

Computed tomography (CT) scan, also known as computerized axial tomography (CAT), or CT scanning computerized tomography is a painless, non-invasive diagnostic imaging procedure that produces cross-sectional images of several types of tissue not clearly seen on a traditional X-ray.

CT scans may be performed with or without contrast medium. A contrast may either be an iodine-based or barium-sulfate compound that is taken orally, rectally, or intravenously which can enhance the visibility of specific tissues, organs, or blood vessels. The duration of the procedure will depend on the area being scanned.

The roles and responsibilities of a nurse extend throughout the whole duration of the CT scan procedure — from taking patient’s history, obtaining informed consent, preparing the patient, and providing education. To ensure the safety and accuracy of the procedure, learn about the nursing interventions and concepts behind computed tomography (CT) scan.

Procedure


The protocol and procedures for computed tomography (CT) scan varies per area but generally, the following steps are followed:

  1. The patient is positioned on an adjustable table inside an encircling body scanner (gantry); straps and pillows may be used to help in maintaining the correct position.
  2. The patient may be instructed to hold his breath during the scanning.
  3. A series of transverse radiographs are taken and recorded
  4. The information is reconstructed by a computer and selected images are photographed.
  5. Once the images are reviewed, an I.V. contrast enhancement may be ordered and additional images are obtained.
  6. The patient is assessed carefully for adverse effects to the contrast medium.

Types


The following are the different types of computed tomography (CT) scans:

Abdominal and pelvic

CT scan of the abdomen and pelvis combines radiologic and computer technology to determine the cause of unexplainable abdominal or pelvic pain and diseases of the bladder, uterus, liver, colon, small bowel, and other internal organs.

Indication Abnormal Results
  • Detects inflammatory process
  • Inspect soft tissue and organs of the abdomen, pelvis and retroperitoneal space
  • Evaluates trauma
  • Helps in the staging of neoplasms
  • Detects edema, hemorrhage, cysts, and tumors
  • Measures effectiveness to chemotherapy
  • Abscesses
  • Cysts
  • Obstructive disease from a tumor or calculi
  • Primary and metastatic neoplasms

Bone and skeletal

Computed tomography (CT) scan of the bone is indicated to provide information and assess the severity of different bone diseases and conditions such as fractures, cancer, and infection.

Indication Abnormal Results
  • Identify any joint abnormalities
  • Determine abnormalities in the upper and lower spine
  • Detect unsual active bone formation
  • Establish the presence and extent of fractures, ligament, or tendon injuries, primary bone tumors, skeletal metastases, and soft tissue tumors
  • Bone fractures
  • Joint abnormalities
  • Primary bone tumors
  • Soft-tissue tumors
  • Skeletal metastasis

Brain

Also known as “cranial CT scan” or “Head CT”.  It is indicated to provide detailed information on head injuries, stroke, brain tumors and other diseases affecting the brain.

Indication Abnormal Results
  • Identify intracranial  abnormalities and lesions
  • Determine focal neurological abnormalities
  • Guides brain surgery or biopsy of brain tissue
  • Evaluate suspected head injury such as subdural  hematoma
  • Monitor the effectiveness of chemotherapy, radiotherapy, or surgery, as part of the management of intracranial tumors
  • Arteriovenous malformation
  • Cerebral atrophy
  • Cerebral edema
  • Congenital anomalies
  • Edema
  • Hydrocephalus
  • Intracranial tumors
  • Intracranial hematoma
  • Infarction

Cardiac calcium scoring 

The goal of a cardiac CT for calcium scoring is to detect coronary artery disease (CAD) at an early stage in individuals who do not yet have any symptoms but are at risk for the disease. Calcium Scoring is most often suggested for males aged 45 years or older, and for females aged 55 and over.

Indication Abnormal Results
  • Identify presence, and extent of calcium buildup in the coronary arteries
  • Evaluates the risk of atherosclerosis and coronary heart disease
  • Score of O: No plaque is present.
  • Score between 1-10: a minimal amount of plaque is present.
  • Score between 11-100: evidence of plaque is present. (Mild or minimal coronary narrowings).
  • Score between 101 and 400: signifies moderate amount of calcified plaque in the arteries (an increased risk of MI)
  • Score >400: reveals extensive calcification and significant narrowing of the arteries due to plaque

Ear

In CT scan of the ear, the radiologist is able to diagnose conditions such as chronic otitis media, ear infections, cholesteatoma, conductive hearing loss, mastoiditis, and cochlear implants.

Indication Abnormal Results
  • Diagnose cochlear abnormalities
  • Investigate ossification of the cochlea coils prior to cochlear implantation
  • Depict osseous changes in the petrous and temporal bone
  • Determine the appropriate surgical and therapeutic method for patients with inner and middle ear disorders
  • Evaluate postsurgical therapy of patients with middle and inner ear disorders
  • Differentiate cholesteatoma from chronic inflammation
  • Evaluate the cause of bilateral hearing loss
  • Cochlear abnormalities
  • Osseous changes of the external auditory canal and middle and inner ear structures
  • Tympanosclerosis

Liver and Biliary Tract

CT scan of the liver and biliary tract provides an in-depth information about the liver, gallbladder, bile ducts, and other related structures.

Indication Abnormal Results
  • Differentiate obstructive and nonobstructive jaundice
  • Detect intrahepatic tumors and abscesses, subphrenic and subhepatic abscesses, cysts, and hematomas
  • Biliary duct dilation
  • Calculi
  • Focal hepatic defects
  • Hepatic cysts
  • Hepatic abscesses
  • Neoplasms
  • Pancreatic carcinoma
  • Small lesions

Orbital

An orbital CT scan provides detailed information about the eye sockets, eyes, and adjacent bone structures.

Indication Abnormal Results
  • Identify the cause of unilateral exophthalmos
  • Assess pathologic conditions of the eye and orbit
  • Detect fractures of the orbit and adjoining structures
  • Encapsulated tumors (benign hemangiomas and meningiomas)
  • Early erosion or expansion of the medial orbital wall
  • Intracranial tumors (gliomas, meningiomas, and secondary tumors)
  • Lymphomas and metastatic carcinomas
  • Space-occupying lesions in the orbit or paranasal sinuses
  • Space-occupying lesions
  • Thickening of the medial and lateral rectus muscles

Pancreas

CT scan of the pancreas may be useful to diagnose cancer of the pancreas, and pancreatitis, and to differentiate pancreatic problems and disorders of the retroperitoneum.

Indication Abnormal Results
  • Diagnose or evaluate pancreatitis
  • Identify pancreatic carcinoma or pseudocyst
  • Differentiate pancreatic disorders and retroperitoneum disorders
  • Acute and chronic pancreatitis
  • Abscesses
  • Adenocarcinoma
  • Ascites
  • Biliary obstructions
  • Cystadenocarcinomas
  • Cystadenomas
  • Islet cell tumors
  • Metastases
  • Pancreatic carcinoma
  • Pseudocysts
  • Pleural effusion

Renal

A renal scan examines the structural and functional abnormalities of the kidney. It is indicated to detect tumors, obstructions, and lesions.

Indication Abnormal Results
  • Identify and diagnose renal abnormalities, such as calculi, obstruction, tumor, polycystic disease, congenital anomalies, and abnormal fluid accumulation
  • Evaluate retroperitoneal pathologies
  • Abscesses
  • Calculi
  • Congenital anomalies
  • Hematomas
  • Kidney infection or damage
  • Lymphoceles
  • Obstructions
  • Polycystic kidney disease
  • Renal cell carcinoma
  • Renal cysts or masses
  • Vascular or adrenal tumors

Spinal

CT scan of the spine is performed to gain insight regarding the vertebrae and other spinal structures and tissues. It is indicated to detect spinal related injuries and diseases of the spine.

Indication Abnormal Results
  • Diagnose lesions and abnormalities of the spine
  • Detect or rule out spinal damage in patients with injury
  • Monitor the results of spinal surgery or therapy
  • Spinal lesions and abnormalities
  • Cervical spondylosis
  • Cervical cord compression
  • Congenital spinal malformations (meningocele, myelocele, and spina bifida)
  • Degenerative processes and structural changes
  • Facet disorders
  • Fluid-filled arachnoidal and other paraspinal cysts
  • Herniated nucleus pulposus
  • Lumbar stenosis
  • Meningioma
  • Neurinoma (schwannoma)
  • Spinal cord compression
  • Spurring of the vertebrae
  • Vascular malformations

Thoracic

CT scan of the chest aids in determining the cause of an unexplained cough, fever, difficulty of breath, chest pain, and other respiratory symptoms. It is recommended for screening of possible lung cancer in its early, curable stage.

Indication Abnormal Results
  • Diagnose a dissection or leak of an aortic aneurysm or aortic arch aneurysm
  • Diagnose the invasion of a neck mass in the thorax
  • Differentiate emphysema or bronchopleural fistula from a lung abscess
  • Distinguish tumors adjacent to the aorta from aortic aneurysms
  • Differentiate tumors from calcified lesions (signifies tuberculosis)
  • Detect the mediastinal lymph nodes
  • Assess primary malignancy that may metastasize to the lungs, especially in the patient with a primary bone tumor, soft-tissue sarcoma, or melanoma
  • Identify the extent of lung diseases such as bronchiectasis, emphysema, and diffuse interstitial lung disease
  • Locate observed neoplasms (e.g., Hodgkin’s disease), especially with the mediastinal involvement
  • Plan radiation therapy
  • Accumulation of fluid, blood, or fat
  • Aortic aneurysms
  • Cysts
  • Enlarged lymph nodes
  • Nodules
  • Pleural effusion
  • Tumors

Contraindication


Computed tomography (CT) is contraindicated in:

  • Pregnant patient (absolute contraindication)
  • Patients with a known allergy to iodine
  • Patients with claustrophobia
  • Patients with renal impairment unless the benefits outweigh the risks
  • Patients with hyperthyroidism or toxic goiter (induce thyrotoxic crisis)
  • Patients with complications after a previous administration of a contrast
  • Patients with severe obesity (usually more than 300 pounds)

Interfering Factors


  • Retained oral or I.V. contrast material from previous diagnostic studies may affect the visibility of the images.
  • Metal objects including eyeglasses, dentures, jewelry, and hairpins

Nursing Responsibilities for CT Scan


The following are the nursing interventions and nursing care considerations for a patient undergoing computed tomography:

Before the procedure

The following are the nursing interventions before computed tomography:

  • Informed Consent. Obtain an informed consent properly signed.
  • Look for allergies. Assess for any history of allergies to iodinated dye or shellfish if contrast media is to be used.
  • Get health history. Ask the patient about any recent illnesses or other medical conditions and current medications being taken. The specific type of CT scan determines the need for an oral or I.V. contrast medium
  • Check for NPO status. Instruct the patient to not to eat or drink for a period amount of time especially if a contrast material will be used.
  • Get dressed up. Instruct the patient to wear comfortable, loose-fitting clothing during the exam.
  • Provide information about the contrast medium. Tell the patient that a mild transient pain from the needle puncture and a flushed sensation from an I.V. contrast medium will be experienced.
  • Instruct the patient to remain still. During the examination, tell the patient to remain still and to immediately report symptoms of itching, difficulty breathing or swallowing, nausea, vomiting, dizziness, and headache.
  • Inform about the duration of the procedure. Inform the patient that the procedure takes from five (5) minutes to one (1) hour depending on the type of CT scan and his ability to relax and remain still.

After the procedure

The nurse should be aware of these post-procedure nursing interventions after computed tomography (CT) scan:

  • Diet as usual. Instruct the patient to resume the usual diet and activities unless otherwise ordered.
  • Encourage the patient to increase fluid intake (if a contrast is given). This is so to promote excretion of the dye.

Normal Results


The following are the expected normal results of computed tomography (CT) scan:

  • Specific type of CT scan reveals normal findings
  • Normal findings on a CT scan shows bone (which has the densest tissue) appears as white areas. Tissues densities will show as shades of gray, and fat tissue appear as black or dark gray. Cerebrospinal fluid (has no tissue) will appear as black. Air will also look black and darker than fat.

Abnormal Results


The abnormal results of a computed tomography (CT) scan varies per area.

  • The specific type of CT dependent on the area of study (see abnormal results above).

Gallery


Images related to computed tomography (CT) scan:

References


Additional resources and references for this guide:

  • Calcium Scoring. (2018). Stmaryhealthcare.org. Retrieved 01 October 2018, from https://www.stmaryhealthcare.org/calciumscoring
  • CT scan – Mayo Clinic. (2018). Mayoclinic.org. Retrieved 01 October 2018, from https://www.mayoclinic.org/tests-procedures/ct-scan/about/pac-20393675
  • What are the Radiation Risks from CT?. (2018). Fda.gov. Retrieved 01 October 2018, from https://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/MedicalImaging/MedicalX-Rays/ucm115329.htm
  • CT Scan Overview — Health Center, University of Connecticut. (2018). Fitsweb.uchc.edu. Retrieved 12 October 2018, from http://fitsweb.uchc.edu/ctanatomy/extrem/index.html
  • Wolters Kluwer Health/Lippincott Williams & Wilkins. (2009). Critical care nursing in a flash. Philadelphia.

Computed Tomography Scan Nursing Diagnostic and Laboratory Tests - Responsibilities, Procedures, and Nursing Considerations