An Introduction to Advanced Imaging Modalities and Additional Procedures



An Introduction to Advanced Imaging Modalities and Additional Procedures









Patients undergoing advanced imaging procedures require special consideration. Many of these patients have been informed that they may have life-threatening illnesses and the procedure they are about to undergo will either confirm or rule out this threat. Many of the advanced imaging procedures are not without pain and risk, and most patients find them anxiety provoking. Even something as innocuous as the diagnostic setting can cause the patient distress.

The atmosphere into which the patient is received is often intimidating for the patient. The environment includes an imaging room, an operating room, or a room where specialized equipment, the patient, and the health care team can be accommodated for the procedures. The health care team may either be masked and gowned or is hidden behind protective screens, which may require that they address the patient by microphone. This, combined with the prospect of a shortened life span, often elicits from the patient’s feelings of helplessness, vulnerability, and fear.

Patients receiving radiation or proton therapy may be in various stages of the grieving process. They know that they have a potentially terminal illness and that the prescribed treatment is being administered in an attempt to improve the quality and length of their lives or provide them some relief from pain. Working in these diagnostic and treatment areas, one must have exceptional technical skills and superior communication and patient-teaching skills. In these areas of patient care, the physician, the registered nurse, the technologist, the sonographer or the therapist, and other health care specialists work together as an interdependent team. Each depends on the other for safe and successful diagnostic and treatment outcomes. All patient care skills presented in the previous chapters of this text need to be applied in these areas.

The intent of this chapter is to provide an introductory overview of various diagnostic imaging procedures and related disciplines, which may be a potential area(s) of specialization. Most of the imaging involve additional training and/or education. Detailed technical discussion of these procedures is beyond the scope of this text and is mentioned only when relevant to patient care instruction.


CARDIAC-INTERVENTIONAL PROCEDURES AND VASCULAR-INTERVENTIONAL RADIOGRAPHY PROCEDURES

Cardiac-interventional procedures (Fig. 18-1) are performed by radiologists or cardiologists to diagnose coronary artery patency and, if indicated, treat atherosclerosis of the coronary arteries by nonsurgical means. These procedures include but are not limited to coronary angiography, aortography, pulmonary angiography, shunt detection, and coronary angioplasty/stent placement. Cardiac-interventional procedures are performed in a cardiac catheterization laboratory with digital fluoroscopy imaging capabilities.

The role of a member of this highly technical team is to participate in the patient’s education, assessment, and general care. One member of the team, either a radiographer/technologist or a nurse, performs a surgical
scrub, dons gown and gloves, and prepares the sterile instruments. Another member of the team performs a sterile skin prep and drapes the patient for the procedure. All members of the team must be alert to any symptoms of respiratory or cardiac distress, be able to monitor vital signs accurately, assist with drug and contrast media administration, apply surgical aseptic technique, and communicate with the patient in a therapeutic manner. Each member of the team must have special education in the problems and potential complications that may result from the procedure. The patient and the medical team must wear radiation protection apparel (shielding) to protect themselves from unnecessary exposure to radiation during these lengthy procedures, which involve use of fluoroscopy and digital imaging.






FIGURE 18-1 Cardiac catheterization image.


The most common sites for insertion of the arterial catheter are the right and left brachial and femoral arteries. The area surrounding the site of catheter insertion is surgically prepared, usually with an iodophor antiseptic as described in Chapter 5. This area is injected with a local anesthetic, and the artery is accessed with a large-bore needle containing a stylet to prevent return blood flow. When the artery has been accessed, the stylet is removed. A guidewire is then inserted through the needle into the artery, and the needle is removed. A catheter is passed over the guidewire into the artery with fluoroscopic guidance. The guidewire is removed, and the catheter is left in place and manipulated to visualize all vessels desired to diagnose potential areas of cardiac pathology.

A low-osmolar contrast media are injected through the catheter, and the cardiac vessels are observed to assess cardiac output; locate and assess the severity of occlusive coronary artery disease; and diagnose congenital heart abnormalities, aneurysms, or other cardiac abnormalities. Treatment of diseased arteries may be performed at the time of the cardiac catheterization. If the coronary arteries are occluded and would benefit from percutaneous transluminal coronary angioplasty, or if the patient has an evolving myocardial infarct, a balloon-tipped catheter is introduced through a guidewire. After the site of occlusion is reached, the balloon is inflated to compress the plaque that is causing the occlusion.

If there is reason to believe that vessel restenosis will occur, a stent may be used to maintain patency of the vessel. A stent is an object that provides support and structure to a vessel. It is introduced in the same way that the balloon is introduced and is left in place when the catheter is removed. Some of the potential complications from these procedures are cardiac arrhythmias, embolic stroke, allergic reactions to the contrast media, and infection or hemorrhage at the catheter insertion site.


Vascular-Interventional Radiography

Vascular-interventional procedures use the same technology and the same surgical aseptic technique as cardiac-interventional procedures to observe major blood vessels throughout the body. The kidneys (Fig. 18-2), adrenal glands, brain, and abdominal aorta are the most common organs to be assessed by this method. The aorta is the typical route to access the vessels of the lower extremities for diagnosis of circulatory impairment of the lower extremities. Potential complications from vascular-interventional procedures are much the same as with coronary angiography. If the kidneys are the focus of the procedure, renal failure is an added potential problem. If the adrenal glands are the focus, fatal hypertensive crisis may occur if the patient has the disease pheochromocytoma. Medication to prevent this is administered several days before the procedure.


Patient Care before and during Cardiac-Interventional and Vascular-Interventional Procedures

The interventional nurses have the primary role to perform most patient care duties and responsibilities before, during, and after these procedures; however, it is important that the technologist is also knowledgeable to participate in the patient care. The technologist must
evaluate the requisition and patient and carry out patient teaching and assessment immediately before the procedure. The technologist must monitor the patient during the procedure and provided follow-up patient care. The process varies somewhat depending on the body organ to be assessed, but the process is largely similar, as follows:






FIGURE 18-2 Arteriogram image.

1. An informed consent is signed after the patient receives instruction from the physician about all that is involved in the procedure, including all potential adverse effects.

2. As with all x-ray procedures, the technologist must ask female patients if there is a chance of pregnancy.

3. Inform the patient before the procedure of the possible immediate need for coronary surgery if complications or outcomes from the catheterization indicate.

4. For angiography of the heart, the patient must abstain from food and fluids for 4 to 8 hours before the procedure; however, for angiography in areas other than the heart, the patient is often asked to be well hydrated before the examination.

5. Instruct the patient to empty the bladder; to remove dentures, jewelry, and clothing; and to put on a patient gown.

6. When the patient enters the catheterization laboratory, explain all that will transpire so that he or she will be prepared for the procedure.

7. Allow the patient to express any anxieties or concerns about what is to occur.

8. Assess the patient for allergies to iodine or any medications to be administered.

9. The peripheral pulses are often identified and marked with a pen, so that they may be quickly assessed during and after the procedure.

10. If ordered, medication is administered to alleviate anxiety.

11. The patient is transferred to the procedure table and placed in a supine position.

12. The area of catheter insertion is shaved and scrubbed with an antiseptic solution.

13. A peripheral intravenous line is started for access and to facilitate administration of drugs as needed. The leads for monitoring the heart rate are placed and connected to the oscilloscope.

14. If the patient is a child, he or she may be allowed to bring a digital device to view to ease feelings of fear and anxiety.

15. Inform the patient that he or she may be asked to cough or take deep breaths during the procedure to ease feelings of nausea or lightheadedness. Coughing may also correct arrhythmias.

16. A local anesthetic may be administered before arterial puncture.

17. The artery is accessed, the guidewire is inserted, and the catheter is placed over the wire.

18. The patient is informed that the contrast agent is about to be injected and is told that he or she will feel a burning or flushed feeling from this and must not be concerned.

19. If the angiography is of the adrenal glands, blood pressure must be monitored continually to assess for evidence of a malignant hypertensive crisis.

20. Images are taken in a timed sequence to demonstrate the arterial and venous blood flow to the organ being studied.

21. Nitroglycerin to dilate blood vessels and other drugs may be administered during the procedure.


Patient Care and Teaching after Cardiac-Interventional and Vascular-Interventional Radiography Procedures

Patient care after cardiac-interventional and vascular-interventional radiography procedures is relatively uniform and must be carried out meticulously to prevent circulatory deficit, thrombus formation, or hemorrhage. In most instances, the patient is transported to the recovery area or to an intensive coronary care area to be monitored after interventional procedures. The technologist must understand the monitoring and care required after these examinations. The patient may be extremely fatigued, and any movement required after the procedure must be done with adequate assistance so there is little demand on the patient. Monitor the patient’s pulse rate on the side of the invasive procedure every 15 minutes for 1 hour and then every hour until an 8- to 12-hour period is complete, and no complication has been detected. The blood pressure is monitored on the side opposite the invasive procedure at the same time intervals. The pulses distal to the site of catheter insertion must also be monitored at frequent, regular intervals for 24 hours after the procedure. After femoral catheterization, the patient should be instructed to move the toes and dorsiflex the feet frequently. Also, instruct the patient to keep the legs straight and still. Assess the extremities for coldness, cyanosis, pallor, numbness, size of one extremity compared with the other extremity, and tingling. Instruct the patient to inform the nurse if he or she has any of the latter symptoms. If a circulatory deficit occurs, surgical intervention may be necessary to correct the problem. The patient should also inform the nurse of any feeling of wetness at the site of the catheter insertion; this may indicate hemorrhaging.

If a femoral artery was used for the catheter insertion, inform the patient that they must remain at bed rest for 10 to 12 hours after the procedure to prevent hemorrhage. A weight or sandbag is often placed over
the site of catheter insertion to apply pressure. The patient should also be told to apply pressure at the insertion site when coughing or sneezing. Do not raise the patient’s head more than 20° during the immediate postcatheterization period.

If the brachial site was used for catheter insertion, the arm on the side of insertion is kept straight with an arm board for several hours, but the patient may be up as soon as the vital signs are stable. Regardless of the site of insertion, the patient must be monitored for 24 hours for external bleeding or for bleeding into the tissues surrounding the catheter insertion site.

Instruct the patient who has received contrast media to increase fluid intake to prevent dehydration and hypotension. This may be contraindicated in some patients with congestive heart failure. Patients are often given intravenous fluid replacement therapy during these procedures, but they should be made aware of the need for increased fluid intake.

Record the time that the procedure began and ended, any drugs or contrast agents administered, and the patient’s tolerance of the procedure on the patients’ electronic medical record. Also, record the instructions given to the patient after the procedure.


COMPUTED TOMOGRAPHY

Computed tomography, also called CT scans, is a diagnostic imaging procedure that can be used to scan body tissues and organs combining x-ray and computer technology. CT (Fig. 18-3) produces multiple cross-sectional images of body organs, which can be reconstructed into accurate three-dimensional images. Because CT has higher radiation doses compared with general radiographic imaging procedures, an emphasis must be placed on minimizing radiation for the patient and the technologist. Radiation protection practices must include patient reducing protocols for all patients and in particular pediatric patients. CT is a highly effective method of diagnosing disease processes of bones, intracranial, soft-tissue structures of the chest, abdomen, pelvis, and organic pathology. Head, neck, thorax, spine, musculoskeletal, abdomen, pelvis, cardiovascular, CT-guided drainage, aspirations, and biopsies are a few of the procedures performed with CT imaging. CT procedures are performed on inpatients, outpatients, critically ill patients, pediatrics patients, and trauma patients. This section on CT presents the procedures for a CT of the abdomen and pelvis.






FIGURE 18-3 Abdominal CT.

Contrast media may be introduced by injection to increase tissue density for body and brain scans. Barium solutions may be used to increase organ density of the gastrointestinal organs.



Patient Care and Instruction before CT

The patient may be receiving contrast media; therefore, all precautions and questioning that precede administration of that drug are included in pre-CT patient care. The technologist must spend time explaining the procedure to the patient in order to alleviate anxiety. Tell the patient that he or she is expected to lie still to ensure clear images. Allow the patient to inspect the equipment and to express any feelings of claustrophobia or fear of the procedure. The technologist must inform the patient that he or she may communicate with the CT technologist through a microphone in the CT room. The technologist should show the patient that he or she will be sitting behind the glass window where he or she can observe, hear, and communicate with the patient at all times (Fig. 18-4).

The technologist must establish a feeling of trust in the patient. It is very frightening for patients to feel that they are in a room alone when receiving an intravenous injection. The extremely anxious patient who is in pain
and unable to lie quietly may need an analgesic or a sedative medication if this can be prescribed.






FIGURE 18-4 CT scanner: gantry.

Inform the patient that he or she may have feelings of nausea, warmth, flushing, and a metallic taste after the contrast media are administered. Place an emesis basin near the patient, where he or she can pick it up easily if need be. Instruct the patient to immediately inform the physician and the nurse in charge if he or she has any feelings of pain during the procedure. Inform the patient that the procedure takes from 5 minutes or less to 20 minutes to complete depending on what part of the body is being scanned. The patient must sign an informed consent before receiving a CT scan. The patient’s medical history and history of allergies must also be taken before this procedure is begun if contrast is administered. In addition, if the patient has known allergies to contrast media, specific protocols must be in place to address allergies.


CT of the Abdomen and Pelvis

Patients who are to have CT of the bowel and abdominal organs are allowed only clear liquids for at least 2 hours and, in some cases, nothing to eat or drink 4 to 6 hours prior to the examination. They may receive a barium contrast agent to drink before the scan. The contrast media may be injected intravenously, which improves the quality of the abdomen and pelvis CT.

The radiographer must spend the same amount of time explaining the procedure to the patient before beginning this examination, as previously discussed. For the bowel and abdominal CT scan, instruct the patient to listen carefully for instructions to breathe, hold the breath, and release the breath. Tell the patient to expect many of these instructions. If the patient is made to feel like the major focus of the procedure and is kept informed, he or she will be more cooperative and relaxed while the examination is in progress. CT can also be used for imaging guidance for biopsies and drainage studies.


Patient Care after CT

Patients who have received sedative or antianxiety medication may not drive themselves. Patients who have come from their homes and plan to return home should be accompanied by a person who can drive them or assist them to get their safely.

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May 8, 2019 | Posted by in GENERAL RADIOLOGY | Comments Off on An Introduction to Advanced Imaging Modalities and Additional Procedures
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