Medical Terminology: Diagnostic Imaging Tests

1. What are Diagnostic Imaging Tests?
Diagnostic imaging tests enable the health care provider to view inside the patient’s body without opening the skin. Commonly used diagnostic imaging tests are:
- X-Rays: X-rays are based on the principle that the X-ray is absorbed by dense objects and will pass through lesser dense objects. Dense objects such as bone appear white on the X-ray file. Less-dense matter such as air appear black, and fluid and fat appear as a lighter shade of gray. X-rays remain a cost-effective way to identify many common disorders.
- Computed Tomography (CT) Scan: A computed tomography (CT) scan makes detailed images of structures (with or without contrast medium) within the body using a doughnut-shaped X-ray machine. While the patient lies within the scanner, an X-ray beam rotates around the patient, creating an image that represents a thin slice of the patient.
- Ultrasound Scan: An ultrasound scan creates an image of organs and structures inside the body using sound waves. High-frequency sound waves are transmitted by a transducer that is placed on the patient’s skin. Sound waves penetrate the skin, bounce off organs and structures in the patient’s body, and are detected by the transducer.
- Magnetic Resonance Imaging (MRI): A closed magnetic resonance imaging (MRI) uses pulsating radio waves in a magnetic field to produce an image of inside the patient’s body. The patient lies on his back on a table. A coil is placed around the area of the patient that is being scanned and a belt is placed around the patient to detect breathing. The table moves into the magnetic field and the belt triggers the MRI scan so that breathing does not interfere with capturing the image. An open MRI does not require that the patient be placed into a machine.
- Positron Emission Tomography (PET) Scan: A positron emission tomography (PET) scan is a nuclear medicine test that creates a roadmap of blood flow in the patient’s body, enabling the health care provider to visualize abnormal blood flow to the patient’s tissues and organs.

2. How an X-Ray Is Taken
The patient is positioned between the X-ray gun and a piece of photographic film. The X-ray machine focuses the X-ray beam at the area of the patient’s body that is being examined. A portion of the X-ray beam passes through the patient’s body, striking the photographic film and leaving a black area on the photographic film. Another portion of the X-ray beam is absorbed by bone and other dense tissue in the patient’s body that appear as shades of gray on the photographic film depending on the density of the tissue. Areas that are not being X-rayed are protected by a lead apron where possible to prevent X-rays from reaching those areas.
An X-ray does not provide a good image of cartilage, ligaments, tendons, and other soft tissues. The health care provider will likely order a CT or MRI scan to examine soft tissue.

3. Abdominal X-Ray
The abdominal X-ray is used to confirm the position of the nasogastric tube, nephrostomy tube, V-P shunt, or dialysis catheter, and locate an ingested foreign body. An abdominal X-ray is used to assess:
- Underlying cause of abdominal or flank pain
- Underlying cause of vomiting and nausea
- Intestinal blockage
- Perforation in the intestine or stomach

Understanding the Abdominal X-Ray
An abdominal X-ray shows the position, size, and shape of the stomach, diaphragm, liver, spleen, and large and small intestines.
Ovaries are not protected with a lead apron during the X-ray because they are located at the site of the X-ray. An abdominal X-ray cannot detect ulcers or bleeding.
The health care provider may also order a CT scan, ultrasound, or IV pyelograph. A KUB X-ray is an abdominal X-ray that examines the kidneys, uterus, and bladder.

4. Extremity X-Ray
The extremity X-ray is used to assess:
- Fracture
- Dislocation
- Tumors
- Deformities/degeneration
- Fluid around joints
- Growths
- Underlying cause of pain in an extremity
- Alignment following treatment
- Infection
- Foreign objects

Understanding the Extremity X-Ray
An extremity X-ray shows damage to hands, wrists, arms, feet, ankles, knees, hips, or legs. The health care provider may not order an X-ray if the results of the X-ray would not alter treatment of the disorder. The health care provider may order a bone scan, CT scan, or MRI if the X-ray does not reveal a disorder.

5. Spinal X-Ray
The spinal X-ray is used to assess:
- Fracture
- Dislocation
- Tumors
- Deformities/degeneration
- Curvature of the spine
- Bone spurs
- Underlying cause of weakness, pain, or numbness
- Alignment following treatment

Understanding the Spinal X-Ray
The spine consists of 33. vertebrae, nearly all separated by a disk that absorbs shock related to movement. There are four types of spinal X-rays:
. Cervical Spine: There are seven vertebrae in the cervical area of the spine.
. Thoracic Spine: There are 12. vertebrae in the thoracic area of the spine.
. Lumbosacral Spine: There are five vertebrae in the lumbar area of the spine and five vertebrae in the sacrum area.
. Sacrum/Coccyx: There are five vertebrae in the sacrum area and four vertebrae in the coccyx area.
Strained back muscles or ligaments are not visible on an X-ray. A disk is cartilage.

6. Mammogram
The mammogram is used to assess the underlying cause of breast discomfort and to assess if the patient has cysts, solid masses, or calcification in the breast.

Understanding the Mammogram
A mammogram is an X-ray that detects palpable and nonpalpable cysts or masses in the breast, and is used to screen for signs of breast cancer. Suspicious masses are biopsied to determine if the mass is cancerous.
Caution: A mammogram is not normally performed if the patient is pregnant. If the mammogram must be performed, a lead apron is placed over the patient’s abdomen.
A mammogram can be performed on a patient who has had breast implants. A mammogram is not performed if the patient is breast-feeding. A breast ultrasound determines if a mass is a cyst or solid mass. A digital mammogram is considered to have the same accuracy as an X-ray mammogram. The health care provider may order the breast cancer (BRCA) gene test if there is a pattern of breast cancer in the patient’s family.
The health care provider must provide the patient with the original mammogram images if requested.

7. Chest X-Ray
The chest X-ray is used to identify foreign objects in the airway and esophagus, and assess for:
- Pulmonary disease or disorders
- Underlying cause of chest pain or respiratory and cardiac problems
- Chest injury
- Positioning of a medical device

Understanding the Chest X-Ray
A chest X-ray shows the position, size, and shape of the collar bone, breast bone, heart, airway, lungs, thoracic spine, ribs, lymph nodes, and blood vessels. The health care provider may also order an echocardiography, ultrasound, MRI, or CT scan.

8. Dental X-Ray
The dental X-ray is used to assess for:
- Cysts, tumors, or abscesses
- Underlying cause of mouth and sinus pain
- Health of teeth
- Position of teeth
- Abnormal structures in the mouth and jaw

Understanding the Dental X-Ray
Dental X-rays are used to assess the condition of the patient’s jaw, mouth, and teeth. There are four types of dental X-rays:
. Panoramic (orthopantogram): This type assesses the temporomandibular joints, the jaw, sinuses, teeth, and nasal area for tumors, fractures, cysts, and impacted teeth, but not cavities.
. Occlusal: This type assesses the palate and lower portions of the mouth for fractures, cleft palate, abscesses, tumors, cysts, and immature teeth.
. Bitewing: This type is a single view of the upper and lower back teeth, and is used to assess the formation of teeth, bone loss, infection, and tooth decay.
. Periapical: This type is a view of a tooth, and is used to assess abscesses, tumors, cysts, and the overall status of the patient’s teeth.

9. Facial X-Ray
The facial X-ray is used to assess:
- Cysts, tumors, or abscesses
- Underlying cause of sinus pain
- Fractures
- Foreign objects

Understanding the Facial X-Ray
A facial X-ray is used to assess facial bones, sinuses, and the orbital cavity. The health care provider may also order a CT scan.

10. Skull X-Ray
The skull X-ray is used to assess:
- Cysts, tumors, or abscesses
- Underlying cause of sinus pain
- Fractures
- Foreign objects

Understanding the Skull X-Ray
A skull X-ray is used to assess the skull and sinuses. The health care provider may also order a CT scan.

11. How a Computed Tomography (CT) Scan Is Taken
A computed tomography (CT) scan makes detailed images of structures within the body using a doughnut-shaped X-ray machine. While the patient lies within the scanner, an X-ray beam rotates around the patient, creating an image that represents a thin slice of the patient. Each rotation takes less than a second.
All slices are stored on a computer. The computer is used to reassemble slices of the patient, enabling the health care provider to identify any abnormalities. Typically, the health care provider will print the image of any slice that indicates an abnormality, which is then saved with the patient’s chart.
The patient may be administered contrast material such as iodine dye. The contrast material makes structures within the patient’s body stand out on the computer by differentiating white, black, and shades of gray. Contrast material is administered intravenously or into joints or cavities of the body. The patient may also be asked to ingest other kinds of contrast material.
A CT scan may be used for staging cancer to assess if the cancer has spread to other sites in the body. A CT scan is also used to identify masses or tumors as well as fluid and the infection process. CT scans guide the health care provider when performing a procedure such as a biopsy.

12. Full Body CT Scan
The full body CT scan is used to assess:
- Growths
- Obstructions
- Inflammation or infection
- Foreign objects
- Bleeding
- Fluid collection
- Pulmonary embolism

Understanding the Full Body CT Scan
A full body CT scan creates an image of the patient’s entire body. A health care provider orders a full body CT scan if it is suspected that the patient may have disorders throughout the body and the health care provider is unable to narrow the disorder to specific areas of the body. This situation may occur if the patient is involved in a severe motor vehicle accident.
Typically, a health care provider orders a CT scan for a specific part of the body rather than ordering a full body scan. A full CT scan is time consuming and usually provides more than enough information necessary for the health care provider to diagnose the patient’s disorder. Some health care providers feel that a full body scan identifies benign growths and other disorders that do not adversely affect the patient and could lead to additional tests and surgery that are unnecessary.
The result of a CT scan is commonly compared to the results of a positron emission tomography (PET) scan to identify cancer.
The health care provider must determine if the patient is allergic to shellfish or iodine. Contrast material may contain iodine and other substances that could cause the patient to have an allergic reaction. In addition, the health care provider should determine if the patient will be administered a sedative to relax the patient during the CT scan. If so, the patient must not drive following the CT scan until the sedative has worn off.

13. CT Scan of the Head
The CT scan of the head is used to provide baseline images before surgery and assess:
- Growths
- Obstructions
- Inflammation or infection
- Foreign objects
- Bleeding
- Fluid collection
- Headache
- Vertigo
- Vision problems
- Broken bones
- Results of facial surgery
- Temporomandibular disorder
- Paget’s disease
- Stroke
- Reasons for change in level of consciousness

Understanding the CT Scan of the Head
The patient’s head is placed into the CT scanner as it takes sliced images of the patient’s skull, brain, and other parts of the patient’s head. The health care provider may order a perfusion CT that to determine the blood supply to areas of the brain. Contrast material is administered IV. Areas of the brain that receive blood are highlighted on the computer image by the contrast material. Areas without blood flow are not highlighted.

14. CT Scan of the Spine
The CT scan of the spine is used to assess:
- Growths
- Obstructions
- Narrowing of the spinal canal
- Deformities
- Fractures
- Inflammation and infection
- Bone compression
- Osteoporosis
- Congenital defects

Understanding the CT Scan of the Spine
The CT scan of the spine creates images of the cervical, thoracic, and lumbosacral spine. All 33. vertebrae and disks are pictured along with the cerebrospinal fluid (CSF). During the scan, the CT scanner can be tilted to follow the curvature of the spine. Depending on the purpose of the scan, the health care provider may require that contrast material be administered intrathecally into the spinal canal.

15. How an Ultrasound Scan Is Taken
An ultrasound scan creates an image of organs and structures inside the body using sound waves similar in concept to how ship crews are able to identify underwater objects while on the surface of the water. High-frequency sound waves are transmitted by a transducer that is placed on the patient’s skin.
Sound waves penetrate the skin, bounce off organs and structures in the patient’s body, and are detected by the transducer. Sound waves detected by the transducer are translated into an image that appears on the ultrasound screen. The health care provider can then measure organs and structures that appear on the image to determine any abnormality.
Images can be printed and included in the patient’s chart or the images can be stored on a computer. An ultra-sound can detect a growth but cannot differentiate between a malignant or benign growth, which is determined by a biopsy. An ultrasound can differentiate between a solid growth and a fluid-filled cyst.
Ultrasound scans are commonly ordered instead of a CT scan or MRI because they are less expensive and, in many situations, give the health care provider sufficient information to assist in reaching a diagnosis.

16. Benign Prostatic Hyperplasia (BPH) Ultrasound
The benign prostatic hyperplasia (BPH) ultrasound is used to guide the health care provider when taking a biopsy of the prostate and to assess:
- Size of the prostate
- Urinary retention
- Urinary blockage

Understanding the Benign Prostatic Hyperplasia Ultrasound
Middle-aged men might experience the urgency to void, hesitancy waiting for the urinary stream, or a weak urinary stream. These may be signs of an enlarged prostate that places pressure on the bladder and blocks the urinary stream. Noncancerous enlarged prostate is referred to as benign prostatic hyperplasia or hypertrophy. An ultrasound is used to assist the health care provider to diagnose the condition.
The BPH ultrasound is also used to help guide the health care provider when taking a biopsy of the prostate, which is routnely performed if the patient’s prostate-specific antigen (PSA) level is elevated. The health care provider may also evaluate the bladder and kidneys while performing the BPH ultrasound to determine urinary retention and kidney stones that may block urinary flow. The BPH ultrasound cannot determine if urinary flow is blocked by the prostate.

17. Transvaginal Ultrasound and Hysterosonogram
Transvaginal ultrasound and hysterosonogram are used to guide the health care provider when removing follicles and to schedule intrauterine insemination. It is also used to assess the:
- Uterus
- Fallopian tubes
- Ovaries
- Endometrial cavity
- Uterine lining
- Ovarian follicle development

Understanding the Transvaginal Ultrasound and Hysterosonogram
When a woman has difficulty conceiving, the health care provider may perform a transvaginal ultrasound or a hysterosonogram, also known as a sonohysterogram. These scans enable the health care provider to assess ovarian follicle development and the endometrium. This assessment may help the health care provider determine when to perform intrauterine insemination.
The transvaginal ultrasound is the preferred method rather than the transabdominal ultrasound for assessing the uterine lining and follicle growth. The transvaginal ultrasound may not display scars or small tumors.

18. Testicular Ultrasound
The testicular ultrasound is used to guide the health care provider when performing a testicular biopsy. It is also used to assess the:
- Testicles
- Epididymis
- Vas deferens
- Scrotum
- Spermatic cord
- Hydrocele and spermatocele

Understanding the Testicular Ultrasound
A health care provider may order a testicular ultrasound if the patient shows signs and symptoms of testicular abnormalities or infertility. The testicular ultrasound displays an image of the patient’s testicles and scrotum, including the epididymis, which is the coiled tube behind the testicle that collects sperm. The testicular ultrasound also displays an image of the vas deferens, which is the tube that connects the prostate gland to the testicles.

19. Abdominal Ultrasound
An abdominal ultrasound is used to guide the health care provider when taking a biopsy or performing a paracentesis. It is also used to assess:
- Liver
- Gallbladder
- Bile ducts
- Spleen
- Pancreas
- Kidneys
- Abdominal aorta

Understanding the Abdominal Ultrasound
An abdominal ultrasound is ordered to view upper abdominal organs and structures. These include the liver, gallbladder, spleen, pancreas, and kidneys. It is also ordered to assist the health care provider in assessing the abdominal aorta, which is the artery located in the back of the chest and abdomen that supplies blood to the legs, abdomen, and organs in the lower portion of the body.
The health care provider may order an ultrasound of specific organs or structures within the abdomen if the abdominal ultrasound shows an abnormal condition in the abdomen.

20. Breast Ultrasound
The breast ultrasound is used to guide the health care provider when taking a biopsy or when draining a cyst. It is also used to assess:
- Mass found on palpation or by mammogram
- Breast of a younger woman whose breasts are dense
- Silicone breast implants
- Breast pain

Understanding the Breast Ultrasound
The breast ultrasound creates an image of all areas of the breast, including portions that are near the chest. A mammogram typically does not show images of the breast that are near the chest. A breast ultrasound is sometimes performed on younger women whose breast tissues are dense, preventing details of the breast to appear on a mammogram.
A health care provider frequently orders a breast ultrasound to assess a lump identified by either palpation or a mammogram. The breast ultrasound can distinguish between a solid mass and a cyst. If it is a solid mass, then the health care provider performs a biopsy to determine if the mass is benign or malignant.
A breast ultrasound does not replace an annual mammogram.

21. Cranial Ultrasound
The cranial ultrasound is used to assess a brain mass in an adult. For a baby, it is used to assess:
- Why the baby has an abnormally large head
- Encephalitis
- Meningitis
- Hydrocephalus
- Periventricular leukomalacia (PVL)
- Intraventricular hemorrhage (IVH)

Understanding the Cranial Ultrasound
A cranial ultrasound creates images of the brain and ventricles. Since ultrasound cannot penetrate bone, a cranial ultrasound is performed on babies up to 18. months old whose cranium has yet to form. A cranial ultrasound is commonly used in premature newborns to assess complications of the premature birth.
A cranial ultrasound is also performed on adults during brain surgery to visualize any masses in the brain. The ultrasound is able to capture the image because a portion of the patient’s cranium is removed during surgery, enabling the ultrasound to penetrate brain tissue.

22. Doppler Ultrasound
The Doppler ultrasound is used to map veins for use as grafts and assess for:
- Narrow blood vessels
- Blood clots (deep vein thrombosis)
- Atherosclerosis
- Stroke

Understanding the Doppler Ultrasound
A Doppler ultrasound is used to assess blood flow through blood vessels. There are four types of Doppler ultrasounds:
. Continuous Wave: This test produces a pulsating audible sound reflecting pulsating blood through a blood vessel.
. Duplex: This test produces an image of the blood vessel along with a computer-generated graph indicating the speed and direction of blood flow.
. Color: This test produces an image of the blood vessel with the speed and direction of blood flow represented by colors on the image.
. Power: This test is similar to the color Doppler; however, the power Doppler is five times as sensitive in detecting blood flow.

23. Fetal Ultrasound
The fetal ultrasound is used to detect ectopic pregnancy and assess:
- Progress of the pregnancy
- Gestational age of the fetus
- Fetal defects
- Number of fetuses
- Placenta
- Amniotic fluid
- Fetal position
- Cervix

Understanding the Fetal Ultrasound
A fetal ultrasound produces an image (sonogram) sonogram the fetus, placenta, and amniotic fluid during pregnancy. The health care provider orders a fetal ultrasound to determine the size, position, and sex of the fetus, and to identify any abnormalities prior to birth. There are two types of fetal ultrasound tests:
. Transabdominal: The ultrasound transducer is placed on the patient’s abdomen.
. Transvaginal: The ultrasound transducer is covered in a latex sheath and inserted into the vagina.
The health care provider must verify that the patient is not allergic to latex if performing a transvaginal ultrasound. A normal fetal ultrasound does not rule out fetal abnormalities or problems with the placenta and amniotic fluid.

24. Pelvic Ultrasound
The pelvic ultrasound is used to guide the health care provider when performing a biopsy and is used to assess for:
- Cause of urinary disorders
- Bladder
- Existence of growths
- Pelvic inflammatory disease (PID)
- Placement of an intrauterine device (IUD)
- Size of pelvic organs and structures
- Fetal position
- Cause of infertility

Understanding the Pelvic Ultrasound
A pelvic ultrasound creates images of the bladder, ovaries, uterus, cervix, fallopian tubes, prostate gland, and seminal vesicles. There are three types of pelvic ultrasound tests:
. Transabdominal: The transducer is moved along the abdomen.
. Transrectal: The transducer is inserted in the rectum.
. Transvaginal: The transducer is covered with a latex sheath and inserted in the vagina.
The health care provider must verify that the patient is not allergic to latex before a transrectal or transvaginal ultrasound is performed.

25. Thyroid and Parathyroid Ultrasound
The thyroid or parathyroid ultrasound is used to guide the health care provider when performing a biopsy and used to assess for:
- Size of the thyroid gland
- Size of the parathyroid gland
- Growths

Understanding the Thyroid and Parathyroid Ultrasound
The thyroid and parathyroid ultrasound is used to create images of the thyroid and parathyroid glands. The thyroid gland produces thyroxine, which controls the patient’s metabolism. The parathyroid gland produces the parathyroid hormone (PTH), which controls the patient’s calcium and phosphorus balance in the blood.
The thyroid and parathyroid ultrasound enables the health care provider to assess the size of these glands but not the production of hormones.

26. How a Magnetic Resonance Image (MRI) Is Taken
Magnetic resonance imaging (MRI) uses pulsating radio waves in a magnetic field to produce an image of the inside of the patient’s body. The patient lies on his or her back on a table. A coil is placed around the area of the patient who is being scanned and a belt is placed around the patient to detect breathing. The table moves into the magnetic field and the belt triggers the MRI scan so that breathing does not interfere with capturing the image. A snapping noise is heard while the MRI scans the patient. The patient may listen to music through headphones to block out the snapping noise.
There are two types of MRI machines: closed MRI and open MRI. In the closed MRI, the patient’s body is entirely enclosed in the machine, whereas in an open MRI only a portion of the patient’s body is enclosed.
The health care provider may order that contrast material be administered to the patient prior to the MRI. The contrast material may be ingested or administered intravenously and highlight areas of the body that are being studied. The MRI produces digital images that are displayed on a computer screen and can be stored for further review by the patient’s health care team. The MRI creates images that are more detailed than images produced by a CT scan, X-ray, or ultrasound.
No metal objects can be on or inside the patient during an MRI, including credit cards. Information on the credit card might be erased by the MRI magnetic field. An X-ray may be ordered to determine if there is any metal inside the patient before the MRI is administered, especially if the patient was in an accident during which metal fragments might have been embedded throughout the body.
However, dental fillings are usually permitted, although the patient is likely to feel tingling in the mouth during the MRI. The patient may experience skin irritation if the patient has iron pigment tattoos.

27. Abdominal MRI
The abdominal MRI is used to guide the health care provider when performing a biopsy and used to assess:
- Size of abdominal organs and structures
- Existence of a growth
- Existence and then identification of a blockage
- Existence of fluid within the abdomen
- Inflammation
- Blood flow

Understanding the Abdominal MRI
An abdominal MRI produces detailed images of organs, structures, and tissues contained within the abdomen. The health care provider may order that the patient be administered contrast material prior to the MRI to highlight parts of the abdomen on the MRI image. This enables the health care provider to identify any subtle abnormalities that may exist in the abdomen.

28. Breast MRI
The breast MRI is used to assess:
- Infection
- Existence of a growth
- Inflammation
- Blood flow
- Women who are at a high risk for breast cancer
- Women who normally have dense breast tissue
- Breast cancer treatment
- Breast implants

Understanding the Breast MRI
A breast MRI produces detailed images of the breast that provide more information to the health care provider than a breast ultrasound or traditional mammogram. Health care providers typically order breast MRIs when other tests such as a mammogram indicate an abnormality. If the abnormality is inflammation, a growth, or blood flow to breast tissues, the health care provider may administer contrast material to enhance the image of those areas of the breast.
Women who are positive for the BRCA1. or BRCA2. gene or whose family members developed breast cancer before the age of 50. are considered at high risk for developing breast cancer and may be recommended for annual breast MRIs to detect early signs of breast cancer. The health care provider may also order an annual breast MRI for women who normally have dense breast tissue. An MRI is better suited to examine dense breast tissue than an ultrasound test.

29. Head MRI
The head MRI is used to assess:
- Infection
- Existence of a growth
- Inflammation
- Blood flow
- Stroke
- Suspected head injury
- Hydrocephaly
- Multiple sclerosis (MS)
- Alzheimer’s disease
- Parkinson’s disease
- Huntington’s disease

Understanding the Head MRI
An MRI of the head is ordered to produce images of the brain and blood vessels that supply blood to the brain to determine the underlying cause of headache, assess for head injury, or determine if the patient has abnormal blood flow or a disorder that affects the brain. Unlike an ultrasound, the head MRI is a closed procedure and does not require that the patient’s skull be opened. There are three types of MRI used to assess the brain:
. Magnetic Resonance Spectroscopy: This test assesses changes in brain chemistry caused by disease.
. Magnetic Resonance Angiogram (MRA): This test assesses the speed, direction, and flow of blood in the brain.
. Diffusion-Perfusion Imaging: This test assesses inflammation, tumors, and stroke, but evaluates the fluid content of the brain.
Health care providers may order an MRI with gadolinium-containing contrast material. Gadolinium can cause nephrogenic fibrosing dermopathy in patients who have kidney failure.

30. Knee MRI
The knee MRI is used to assess:
- Knee structures and tissues
- Existence of a growth
- Arthritis
- Tendons, ligaments, cartilage, or meniscus
- If arthroscopy is required

Understanding the Knee MRI
A knee MRI produces detailed images of structures and tissues contained within the knee. This enables the health care provider to identify any abnormalities that may exist in the knee, including damage to tendons, ligaments, cartilage, and fluid. The health care provider may order a knee MRI to assess if the patient requires arthroscopy of the knee.

31. Shoulder MRI
The shoulder MRI is used to assess:
- Shoulder structures and tissues
- Existence of a growth
- Arthritis
- Tendons, ligaments, cartilage, bones, or muscles
- Rotator cuff disorders
- If arthroscopy is required

Understanding the Shoulder MRI
The shoulder MRI is ordered to show the health care provider detailed images of inside the shoulder, including ligaments, cartilage, muscles, and bone structure within the shoulder and fluid. These images are more detailed than can be achieved using ultrasound and CT scans, and are commonly ordered to assess shoulder pain that is unexplained by other signs or symptoms.

32. Spinal MRI
The spinal MRI is used to assess:
- Spinal structures and tissues
- Ruptured disk
- Sciatica
- Spinal stenosis
- Existence of growths
- Arthritis
- Damaged nerves

Understanding the Spinal MRI
The spinal MRI shows detailed images of the patient’s spine. This includes the cervical, thoracic, and lumbosacral spine. The spinal MRI helps the health care provider assess if the patient has spinal disk disorders or spinal stenosis, as well as tumors and arthritis. The health care provider also orders a spinal MRI to assess unexplained spinal pain.

33. Positron Emission Tomography (PET) Scan
The positron emission tomography (PET) scan is used to assess:
- Blood flow to organs and tissues
- Metabolic activity or organs
- Stroke and transient ischemic attack (TIA)
- Multiple sclerosis
- Parkinson’s and Alzheimer’s diseases
- Epilepsy
- Coronary artery disease
- Presence of cancer and to determine if the cancer has metastasized

Understanding the Positive Emission Scan
The positive emission scan is ordered to study blood flow and metabolic activity within a patient’s body. Health care providers frequently combine results from the PET scan with CT scan results to obtain a thorough understanding of how well tissues and organs are being infused with blood.
Sometimes a CT scan is performed along with a PET scan. The tracer contains low-level radiation that will rarely lead to tissue damage. The tracer is flushed from the patient’s body in 24. hours following the scan. It is rare that a patient will have an allergic reaction to the tracer. The health care provider may order a single photon emission computed tomography (SPECT) scan to determine if a patient with chest pain is at risk for cardiac arrest.

34. How a Positron Emission Tomography (PET) Scan Is Taken
A positron emission tomography (PET) scan is a nuclear medicine test that creates a roadmap of blood flow in the patient’s body, enabling the health care provider to visualize abnormal blood flow to the patient’s tissues and organs.
A radioactive chemical called a tracer and a special camera that detects the tracer inside the patient’s body are the keys to a PET scan. The health care provider administers the tracer into the patient’s veins prior to the scan. The tracer gives off positrons, which are very small charged particles that can be detected by the PET scan camera. The PET scan camera takes a series of images, each capturing the position of positrons in the body. These images are stored and replayed on a computer screen. These images show the tracer containing blood as the blood makes its way into organs and tissues, giving the health care provider a clear picture of blood flow within the body.

35. Bone Mineral Density (BMD) Test
The bone mineral density (BMD) test is ordered to assess for osteoporosis, the progression of osteoporosis, and the impact of long-term corticosteroid treatment.

Understanding the Bone Mineral Density Test
The bone mineral density test measures the density of bone to assess if the patient has osteopenia or osteoporosis. A low bone density might result in increased risk for fracture. There are five ways to measure bone mineral density:
. Ultrasound: This test uses sound waves to determine the density of bone. However, this method does not assess the hip and spine, which are bones that commonly fracture because of low bone mineral density.
. Dual-Photo Absorptiometry (DPA): This method uses a low-dose radioactive tracer to measure bone density in all bones, including the hip and spine.
. Quantitative Computed Tomography (QCT): This method measures the density of the vertebra; however, this is less accurate than the DPA, DEXA, and P-DEXA methods.
. Dual-Energy X-Ray Absorptiometry (DEXA): This method uses two X-ray beams to measure bone density and can measure up to 2% bone loss, making it the most accurate way to measure bone mineral density.
. Peripheral Dual-Energy X-Ray Absorptiometry (PDEXA): This method measures bone density in the arms and legs, but cannot be used to measure the bone density of the hip or spine.

36. Bone Scan
A bone scan assesses infection, trauma, and metastasized cancer growth to the bone.

Understanding the Bone Scan
A radioactive tracer is injected in the patient’s vein. The tracer is removed from the blood into the bone. A gamma camera takes an image of the tracer as the tracer is absorbed. Lack of absorption indicates bone infarction and possibly cancer. Areas of high absorption might indicate an infection, tumor, or fracture.

Basic Questions
Diagnostic Imaging Tests

1. What appears white on an X-ray?
Dense objects such as bone appear white on an X-ray.

2. What appears black or a lighter shade of gray on an X-ray?
Less-dense matter such as air appear black and fluid and fat appear as a lighter shade of gray.

3. Why are X-rays still taken rather than using more advanced imaging technology?
X-rays remain a cost-effective way to identify many common disorders.

4. How does a computed tomography (CT) scan work?
A CT scan makes detailed images of structures within the body using a doughnut-shaped X-ray machine. While the patient lies within the scanner, an X-ray beam rotates around the patient, creating an image that represents a thin slice of the patient.

5. How does an ultrasound scan work?
An ultrasound scan creates an image of organs and structures inside the body using sound waves. High-frequency sound waves are transmitted by a transducer that is placed on the patient’s skin. Sound waves penetrate the skin, bounce off organs and structures in the patient’s body, and are detected by the transducer.

6. How does a magnetic resonance imaging (MRI) work?
An MRI uses pulsating radio waves in a magnetic field to produce an image of inside the patient’s body. The patient lies on his or her back on a table. A coil is placed around the area of the patient that is being scanned and a belt is placed around the patient to detect breathing. The table moves into the magnetic field and the belt triggers the MRI scan so that breathing does not interfere with capturing the image.

7. How does a positron emission tomography (PET) scan work?
A PET scan is a nuclear medicine test that creates a roadmap of blood flow in the patient’s body, enabling the health care provider to visualize abnormal blood flow to the patient’s tissues and organs.

8. Why would a health care provide not order an X-ray?
An X-ray does not provide a good image of cartilage, ligaments, tendons, and other soft tissues; therefore, the health care provider will likely order a CT scan or MRI to examine soft tissue.

9. Why might a health care provider not order an extremity X-ray if the patient has an obvious fracture?
The health care provider may not order an X-ray if the results of the X-ray would not alter treatment of the disorder.

10. If the patient who is suspected of having a bone disorder is given an X-ray and the X-ray does not reveal the disorder, what might the health care provider do?
The health care provider might order a bone scan, CT scan, or MRI if the X-ray does not reveal a disorder.

11. What is a lumbosacral spine X-ray?
A lumbosacral spine X-ray examines the five vertebrae in the lumbar area of the spine and five vertebrae in the sacrum area.

12. How would you respond if the patient said that the health care provider ordered an X-ray because she suspects injury to a spinal disk?
Explain that the health care provider probably ordered a different imaging test because a spinal disk is cartilage and cartilage is not visible on an X-ray.

13. What is the purpose of a bitewing X-ray?
The bitewing type of X-ray is a single view of the upper and lower back teeth and is used to assess the formation of teeth, bone loss, infection, and tooth decay.

14. Why might a patient be administered contrast material before undergoing a CT scan?
The contrast material makes structures within the patient’s body standout on the computer by differentiating between white, black, and shades of gray.

15. What are the limitations of the ultrasound when assessing growths?
An ultrasound can detect a growth but cannot differentiate between a malignant or benign growth, which is determined by a biopsy. An ultrasound can differentiate between a solid growth and a fluid-filled cyst.

16. Why are ultrasounds ordered instead of a CT scan or MRI?
Ultrasound scans are commonly ordered instead of a CT scan or MRI because they are less expensive and in many situations give the health care provider sufficient information to assist to reach a diagnosis.

17. What is the purpose of a BPH ultrasound?
The benign prostatic hyperplasia (BPH) ultrasound is used to guide the health care provider when taking a biopsy of the prostate and to assess for the size of the prostate, urinary retention, and a urinary blockage.

18. What is a limitation of the BPH ultrasound?
The benign prostatic hyperplasia ultrasound cannot determine if urinary flow is blocked by the prostate.

19. What is the preferred method of assessing the uterine lining and follicle growth?
The transvaginal ultrasound is the preferred method for assessing the uterine lining and follicle growth rather than the transabdominal ultrasound.

20. What is a common reason that the health care provider orders a breast ultrasound?
A health care provider frequently orders a breast ultrasound to assess a lump identified by either palpation or from a mammogram. The breast ultrasound can distinguish between a solid mass and a cyst.

21. What is the purpose of a Doppler ultrasound?
The Doppler ultrasound is used to map veins for use as grafts and to assess narrow blood vessels, and for blood clots (deep vein thrombosis), atherosclerosis, and stroke.

22. What is a continuous wave Doppler?
Continuous wave Doppler produces a pulsating audible sound, reflecting pulsating blood through a blood vessel.

23. What is the purpose of a color Doppler?
Color Doppler produces an image of the blood vessel with the speed and direction of blood flow represented by colors on the image.

24. Why might a health care provider order a fetal ultrasound?
The fetal ultrasound is used to detect ectopic pregnancy and assess progress of the pregnancy, gestational age of the fetus, for fetal defects, the number of fetuses, the placenta, amniotic fluid, the fetal position, and the cervix.

25. What is the difference between a closed and open MRI?
In the closed MRI, the patient’s body is entirely enclosed in the machine, whereas only a portion of the patient’s body is enclosed in an open MRI machine.