MRI scan facts

• MRI scanning uses magnetism, radio waves, and a computer to produce images of body structures.
• MRI scanning is painless and does not involve x-ray radiation
• Patients with heart pacemakers, metal implants, or metal chips or clips in or around the eyes cannot be scanned with MRI because of the effect of the magnet.
• Claustrophobic sensation can occur with MRI scanning.

What is an MRI scan?

An MRI (or magnetic resonance imaging) scan is a radiology technique that uses magnetism, radio waves, and a computer to produce images of body structures. The MRI scanner is a tube surrounded by a giant circular magnet. The patient is placed on a moveable bed that is inserted into the magnet. The magnet creates a strong magnetic field that aligns the protons of hydrogen atoms, which are then exposed to a beam of radio waves. This spins the various protons of the body, and they produce a faint signal that is detected by the receiver portion of the MRI scanner. The receiver information is processed by a computer, and an image is produced. The image and resolution produced by MRI is quite detailed and can detect tiny changes of structures within the body. For some procedures, contrast agents, such as gadolinium, are used to increase the accuracy of the images.

When are MRI scans used?

An MRI scan can be used as an extremely accurate method of disease detection throughout the body and is most often used after the other testing fails to provide sufficient information to confirm a patient's diagnosis. In the head, trauma to the brain can be seen as bleeding or swelling. Other abnormalities often found include brain aneurysms, stroke, tumors

Mammogram, X-ray of the Breast

Mammography is the X-ray imaging that is used to screen for abnormalities in the breast. Mammography plays a key role in the early detection and treatment of breast cancer and helps to reduce the number of deaths caused by the disease.

Mammography screening is recommended for all women over the age of 40 years or for younger women who have a family history of breast cancer.

How does mammography work?

For a mammogram to be taken, the breast is squeezed and spread out between two hard, flat plates. The mammogram then produces black and white X-ray images of the breast which can be displayed on a computer screen and assessed by an expert in breast cancer.

Mammograms are very accurate but can still sometimes miss cancer. Therefore, all women are advised to have a clinical breast exam (CBE) in which the appearance and feel of the breasts is checked by a healthcare provider who is trained in breast examination.

During a CBE, the armpits are also checked for the presence of lumps and other changes. Women should have a clinical breast exam every 3 years starting from the age of 20 years and every year after the age of 40

Timing of mammography

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Mammography may be mildly painful or uncomfortable and is best avoided before periods when the breasts are more sensitive. An ideal time for a mammography is a week after the last period finished, when the breasts are less tender.Mammography may be mildly painful or uncomfortable and is best avoided before periods when the breasts are more sensitive. An ideal time for a mammography is a week after the last period finished, when the breasts are less tender.

On the day of mammography, it is advisable not to wear antiperspirants, perfumes, lotions, powders, deodorants or jewellery as these can interfere with the images produced.

The patient is asked to place the breast between two plastic plates which press gently on the breast to flatten it. The pressure lasts for around a few seconds and two images of each breast are taken - one from the side and another from above. The whole procedure takes around 15 minutes.

What happens afterwards?

If a breast lump is detected via mammography, further tests are advised including a fine needle aspiration or a biopsy for confirmation of the diagnosis and commencement of treatment. The mammogram also shows how dense the breast tissue is.

While some breasts have more fatty tissue than fibrous and glandular, others have the opposite. The former are termed low density breasts and the latter high density breasts. High density breast tissue is more at risk of breast cancer

How does mammography work?

For a mammogram to be taken, the breast is squeezed and spread out between two hard, flat plates. The mammogram then produces black and white X-ray images of the breast which can be displayed on a computer screen and assessed by an expert in breast cancer.

Mammograms are very accurate but can still sometimes miss cancer. Therefore, all women are advised to have a clinical breast exam (CBE) in which the appearance and feel of the breasts is checked by a healthcare provider who is trained in breast examination.

During a CBE, the armpits are also checked for the presence of lumps and other changes. Women should have a clinical breast exam every 3 years starting from the age of 20 years and every year after the age of 40.

Mammography is the X-ray imaging that is used to screen for abnormalities in the breast. Mammography plays a key role in the early detection and treatment of breast cancer and helps to reduce the number of deaths caused by the disease.

Mammography screening is recommended for all women over the age of 40 years or for younger women who have a family history of breast cancer.

Ultrasound is a type of oscillating sound pressure wave that has a higher frequency than human hearing is able to detect. Ultrasound is not a unique type of sound, therefore, but is classified differently due to the fact that humans cannot hear it. Ultrasound has a frequency greater than 20kHZ, which is beyond the frequency limit of sounds that humans are able to hear.

In 1794, Lazzaro Spallanzani demonstrated that bats did not rely on vision but, rather, utilized the echo of a type of sound that was inaudible to the human ear to navigate their path. This later led to further research in the field and eventually led to the concept of ultrasound that we know now.

Medical Uses

Ultrasound has proven to be useful in many fields including medical imaging, which is also referred to as sonography. The technique is utilized by veterinarians and medical practitioners and offers a way to scan for objects and measure distances in living bodies.

The concept of using high frequency sound waves for medical optical imaging was first penned in 1939 by Sokolov, although the initial images produced were low quality in terms of contrast and sensitivity.

Over the following years, the technique was tweaked such that ultrasonography is has been used in medical practices as a tool to visualize muscles, tendons, internal organs and tumors for more than 50 years. It is widely known for its use in prenatal care, with its ability to visualize and monitor the growth of a growing fetus during pregnancy.

Ultrasonography offers many tangible benefits, including:

• Portable devices
• Cost-effective
• Non-destructive nature

Given these benefits, ultrasound is becoming increasingly common in emergency medicine to visualize internal issues quickly and help in emergency decision-making

Researchers have discovered that a protein implicated in human longevity may also play a role in restoring hearing after noise exposure. The findings, where were published in the journal Scientific Reports, could one day provide researchers with new tools to prevent hearing loss.

The study reveals that a gene called Forkhead Box O3 (Foxo3) appears to play a role in protecting outer hair cells in the inner ear from damage. The outer hair cells act as a biological sound amplifier and are critical to hearing. When exposed to loud noises, these cells undergo stress. In some individuals, these cells are able to recover, but in others the outer hair cells die, permanently impairing hearing. While hearing aids and other treatments can help recovered some range of hearing, there is currently no biological cure for hearing loss.

"While more than a hundred genes have been identified as being involved in childhood hearing loss, little is known about the genes that regulate hearing recovery after noise exposure," said Patricia White, Ph.D., a research associate professor in the University of Rochester Medical Center (URMC) Department of Neuroscience and lead author of the study. "Our study shows that Foxo3 could play an important role in determining which individuals might be more susceptible to noise-induced hearing loss

Hysterosalpingogram

Test Overview

A hysterosalpingogram (HSG) is an test. It looks at the inside of the uterus and fallopian tubes and the area around them. It often is done for women who are having a hard time getting pregnant(infertile)

During the test, a dye (contrast material) is put through a thin tube. That tube is put through the vagina and into the uterus. Because the uterus and the fallopian tubes are hooked together, the dye will flow into the fallopian tubes. Pictures are taken using a steady beam of X-ray (fluoroscopy)as the dye passes through the uterus and fallopian tubes. The pictures can show problems such as an injury or abnormal structure of the uterus or fallopian tubes. They can also show a blockage that would prevent an egg moving through a fallopian tube to the uterus. A blockage also could prevent sperm from moving into a fallopian tube and joining (fertilizing) an egg. The test also may find problems on the inside of the uterus that prevent a fertilized egg from attaching (implanting) to the uterine wall.

Why It Is Done

A hysterosalpingogram (HSG) is done to:

• Check for a blocked fallopian tube. The test often is done for a woman who is having a hard time getting pregnant. An infection may cause severe scarring of the fallopian tubes and block the tubes. This can prevent pregnancy.Once in a while, the dye used during the HSG will push through and open a blocked tube.
• Find problems in the uterus, such as an abnormal shape or structure. The test can also look for an injury, polyps,fibroids,adhesions,or a foreign object in the uterus. These types of problems may cause painful menstrual periods or repeated miscarriages
• See if tubal implants for permanent birth control are blocking the fallopian tubes.
• See if surgery to reverse a tubal ligation has been successful.

How To Prepare

Before a hysterosalpingogram (HSG), tell your doctor if you:
• Are or might be pregnant.
• Have a pelvic infection (pelvic inflammatory disease or a sexually transmitted infection, such as gonorrhea or chlamydia
• Are allergic to the iodine dye used or any other substance that has iodine. Also tell your doctor if you have asthma or are allergic to any medicines. Tell him or her if you have had a serious allergic reaction(anaphylaxis) from any substance. (For example, have you had a reaction to the venom from a bee sting or from eating shellfish?)
• Have any bleeding problems or are taking any blood-thinning medicines. Examples of these medicines are aspirin and warfarin(Coumadin)
• Have a history of kidney problems or diabetes,especially if you take metformin (such as Glucophage)to control your diabetes.The dye used during the test can cause kidney damage in people with poor kidney function. If you have a history of kidney problems, blood test (creatinine,blood urea nitrogen)may be done before the test. These check to see that your kidneys are working well.

Intravenous Pyelogram (IVP)

Test Overview

An intravenous pyelogram (IVP) is an X-ray test that provides pictures of kidneys,bladder,ureters,and urethra. An IVP can show the size, shape, and position of the urinary tract, and it can evaluate the collecting system inside the kidneys

During IVP, a dye called contrast material is injected into a vein in your arm. A series of X-ray pictures is then taken at timed intervals.

IVP is commonly done to identify diseases of the urinary tract, such as kidney stones, tumors, or infection. It is also used to look for problems with the structure of the urinary tract that were present from birth (congenital).

An ultrasound or a computed tomography (CT) scan may be combined with an IVP if more details about the urinary tract are needed. A computed tomography intravenous pyelogram (CT/IVP) is usually done to look for the cause of blood in the urine

Why It Is Done

An intravenous pyelogram (IVP) is done to:

• Look for problems with the structure of the urinary tract.
• Find the cause of blood in the urine.
• Find the cause of ongoing back or flank pain.
• Locate and measure a tumor of the urinary tract.
• Locate and measure a kidney stone.
• Find the cause of recurring urinary tract infections.
• Look for damage to the urinary tract after an injury.

How To Prepare

Before having an intravenous pyelogram (IVP), tell your doctor if:

You are or might be pregnant

You are breastfeeding. The contrast material used in this test can get into your breast milk. Do not breastfeed your baby for 2 days after this test. During this time, you can give your baby breast milk you stored before the test, or formula. Discard the breast milk you pump for 2 days after the test.

• You have an intrauterine device(IUD) in place.
• You are allergic to the iodine dye used as the contrast material for X-ray tests or to anything else that contains iodine.
• You have ever had a serious allergic reaction (anaphylaxis), such as after being stung by a bee or from eating shellfish.
• Within the past 4 days, you have had an X-ray test using barium contrast material (such as a barium enema).
• You have had kidney problems in the past or have diabetes,especially if you take metformin(Glucophage)  to control your diabetes.The contrast material used during an IVP can cause kidney damage in people who have poor kidney function. If you have had kidney problems in the past, blood test (creatinine blood urea nitrogen)may be done before the test to make sure that your kidneys are working properly.

You may need to stop eating and drinking for 8 to 12 hours before the IVP. You also may need to take a laxative the evening before the test (and possibly have an enema the morning of the test) to make sure that your bowels are empty.

This test is often done in children to see if they may have an abnormal backflow of urine (vesicoureteral reflux).Prepare your child for exams and tests that are needed. Explain them in a simple way. Use positive words as much as possible. Doing so will help your child understand what to expect and can help reduce fears.

Creatinine Testing Prior to Gadolinium Administration

Routine creatinine testing prior to contrast administration is not necessary in all patients.  Serum creatinine with calculation of eGFR should be performed in patients with any of the following risk factors:

• Age over 60
• History of kidney disease, including tumor and transplant
• Family history or kidney failure or disease
• Diabetes treated with insulin or other prescribed medications
• Hypertension requiring medication
• Multiple myeloma
• Solid organ transplant
• History of severe liver disease

Gadolinium in Patients with Impaired Renal Function

Nephrogenic systemic fibrosis (NSF), a serious, debilitating, and sometimes fatal scleroderma-like disorder, is associated with the administration of intravenous gadolinium. The primary risk factor is renal failure (patient on dialysis or with a GFR < 30). The guidelines for administration of gadolinium are as follows:

• Gadolinium should be avoided or minimized in patients with known renal failure (eGFR<30ml/min) or renal insufficiency (eGFR<90ml/min). If enhanced MR is deemed necessary by the radiologist, the exam will be performed after informed consent, with single-dose Multihance or other alternative to Omniscan (gadodiamide). Omniscan (gadodiamide) should be avoided in patients with any amount of renal insufficiency.
• Single-dose Multihance or other gadolinium contrast agent will be used in place of Omniscan (gadodiamide) for enhanced MR studies in patients with any known renal insufficiency (eGFR<90 ml/min).
• Patients with an eGFR>90ml/min reported within 30 days, and who have not had intervening chemotherapy or other treatment or condition that might deteriorate renal function, may receive any gadolinium agent.
• Patients with known renal insufficiency should not receive additional doses of gadolinium contrast within a 48 hour period. If additional gadolinium contrast is required for a patient with known renal insufficiency within 48 hours of the initial dose, Radiologist approval is required.
• Informed consent, obtained by a physician, will be required for gadolinium injection in dialysis patient and all patients with known renal insufficiency with an eGFR<30 ml/min, and for all dialysis patients. A written order for the gadolinium contrast is required from the radiologist. This order must arise explicitly from the radiologist and NOT from either a referring physician or an MR imaging protocol standing order. The name of the patient, the name and specific brand of gadolinium contrast, dose, route, and rate of administration should all be explicitly specified on the order, along with the date and signature of the requesting radiologist.
• Verbal and written instructions will be given to renal insufficiency patients after receiving intravenous gadolinium. Patients with renal insufficiency who receive gadolinium-containing contrast agents should be aware of the following possible signs and symptoms of NSF/NFD, as directed by the FDA warning, and advised to seek medical attention if these occur: swelling and tightening of the skin; difficulty extending the joints of arms, hands, legs, and feet; weakness, reddened or darkened areas on the skin; burning or itching of the skin; and deep bone pain in the hips and ribs.
• Hemodialysis patients who receive intravenous gadolinium contrast will receive dialysis treatments immediately after the procedure (initiated within 2 hours) and the day following the enhanced MR exam.
• For administration to patients on chronic ambulatory peritoneal dialysis (CAPD) or continuous cycler-assisted peritoneal dialysis (CCPD) (also known as automated peritoneal dialysis, or APD), there appears to be strong reason to hesitate to administer these agents. As noted above, this process of dialysis seems to be relatively ineffective at clearing the gadolinium from the body. Thus, special caution should be exercised when deciding whether a peritoneal dialysis patient should receive gadolinium-based MR contrast agents. If it is decided that they should be administered such agents, administration of the lowest reasonable dose is strongly recommended. In the past, it had been recommended that the patient avoid periods of a dry abdomen (i.e., no dialysate in the peritoneal cavity) and that the patient be advised to begin additional dialysis self-treatments or CCPD treatments immediately upon the termination of the MR examination in which the GBMCA was administered. These suggestions seemed prudent, although the efficacy of these recommendations had not been established. However, in light of the near-total apparent ineffectiveness of peritoneal dialysis at clearing the gadolinium from the body, it may well be worth considering immediate initiation of hemodialysis in peritoneal dialysis patients who receive even a low dose of a GBMCA (gadolinium based MR contrast agent), or not administering the agent if clinically feasible.
• Withholding clinically indicated gadolinium contrast can also be associated with its own risks, which should be considered in the decision-making process for all patients with kidney disease.

 Prepare a Patient for an MRI

General Instructions

Patients are prepared for an MRI by removing all unnecessary metallic objects, including jewelry and drug delivery patches.

All patients and other individuals in the room during the actual scan receive acoustic noise protection. When possible, two forms of noise protection are utilized, i.e. ear plugs and pads or head phones.

Patient Screening Prior to MRI

Patients are thoroughly screened for any absolute contraindications to an MRI which are: 

• Intracranial aneurysm clips
• Ocular metallic foreign bodies
  • If the patient or guardian is not sure of the presence of an ocular object, but there is a significant likelihood based upon the individual's past experience or occupation, MRI is not performed until independent verification is made.
  • To independently verify the presence or absence of an ocular object, the patient should be referred for an x-ray procedure. A single Water's view is normally sufficient; however, a supplementary CT exam of the orbits using 3mm contiguous slices may also be required at the discretion of the attending radiologist following review of the plain film.
• Cardiac pacemakers
• Any electrically active implant

Patients are also screened for other potential contraindications to an MRI which include:

• Cochlear implants
• Any known ferromagnetic metallic materials within the body
• Pregnancy
• Coils, stents, and filters 
  • Patients with a history of coil, filter or stent implantation are not granted access to the MRI scan room until the device is identified and the manufacture’s MRI labeling information is reviewed and approved. 
  • Patient is scanned according to the manufacturer guidelines in regards to surface coil selection, dB/dt, T/m, G/cm monitoring of Specific Absorption Rate (SAR) and magnet strength, and configuration.

Contrast Administration in Patients Receiving Metformin

Metformin should be discontinued at the time of the procedure, withheld for 48 hours subsequent to the procedure, and reinstituted only after renal function has been re-evaluated and found to be normal.

Contrast Administration in Pregnant Patients

The iodine content of contrast media has the potential to cause hypothyroidism in the neonate. Pregnant women who receive an intravenous iodinated contrast agent are counseled that neonatal thyroid function should be checked in the first week of life. Informed consent is obtained prior to the administration of contrast in pregnant patients.

Contrast Administration in Patients with Elevated Creatinine

Estimated glomerular filtration rate is a better predicator of renal dysfunction than creatinine alone. The decision to proceed with contrast administration in patients with an estimated GFR < 45 ml/min/1.732 is a matter of clinical judgment, based on the individual circumstances of the patient and following consultation between the radiologist and requesting physician. Strategies to prevent nephropathy in patients with renal impairment include hydration, reduction of contrast dose, and discontinuation of nephrotoxic drugs. A critical diagnostic study should not be delayed because of excessive concern regarding possible contrast nephropathy.        

Contrast Administration in Patients with Renal Failure

Patients on dialysis can receive IV contrast, and early post-procedural dialysis is not routinely required; however, the fact that a patient is on dialysis should not be regarded as automatically allowing the administration IV contrast. The administration of contrast may jeopardize the return of renal function in patients who are receiving dialysis for acute renal failure and may further worsen renal function in patients who still make some urine but receive dialysis intermittently. The volume of iv contrast should also be considered in patients on dialysis who are at risk for volume overload.

Premedication Instructions for Patients with Contrast Allergies

Prednisone 50mg po at 13 hours, 7 hours and 1 hour prior to planned administration of intravenous contrast plus diphenhydramine 50mg po, iv or im at 1 hour prior to planned administration of intravenous contrast

Or

Methylprednisolone 32mg po at 12 hours and 2 hours prior to planned administration of contrast plus diphenhydramine 50 mg po, iv or im at 1 hour prior to the planned administration of contrast

Or

Hydrocortisone 200mg iv at 13 hours, 7 hours and 1 hour prior to planned administration of intravenous contrast if patient is unable to take po medications

Creatinine Testing Prior to Contrast Administration

Routine creatinine testing prior to contrast administration is not necessary in all patients. The major indications are age over 60, history of renal insufficiency, diabetes mellitus, or hypertension. 

 Prepare a Patient for a CT

General Instructions

Little preparation is needed for a CT scan. Patients are asked to drink plenty of water both before and after the exam, especially if the exam is performed with oral or intravenous contrast. Patients will be asked to remove jewelry and other metallic objects that might interfere with the scan. 

Patient Screening Prior to Administration of Iodinated Contrast

Prior to the administration of iodinated contrast, patients are screened for the following:

• Previous reactions to iodinated contrast media
• All severe allergies and reactions (both medications and food)
• History of diabetes, kidney disease, pheochromocytoma, solitary kidney, kidney or other transplant, or myeloma
• Current use of any metformin-containing medications
• For women of child-bearing age, currently or possibly pregnant or currently breast-feeding.

What is Abdominal Ultrasound Imaging?

Ultrasound is safe and painless, and produces pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the probe through the gel into the body. The transducer collects the sounds that bounce back and a computer then uses those sound waves to create an image. Ultrasound examinations do not use ionizing radiation (as used in x-rays), thus there is no radiation exposure to the patient. Because ultrasound images are captured in real-time, they can show the structure and movement of the body's internal organs, as well as blood flowing through blood vessels.

Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions.

Children's (pediatric) abdominal ultrasound imaging produces pictures of the internal organs and blood vessels located within a child's abdomen.

A Doppler ultrasound study may be part of a child's abdominal ultrasound examination.

Doppler ultrasound is a special ultrasound technique that allows the physician to see and evaluate blood flow through arteries and veins in the abdomen, arms, legs, neck and/or brain (in infants and children) or within various body organs such as the liver or kidneys.

Children's (Pediatric) Ultrasound - Abdomen

Children’s (pediatric) ultrasound imaging of the abdomen is a safe, noninvasive test that uses sound waves to produce a clear picture of the internal organs and blood vessels within your child’s abdomen. Ultrasound does not use ionizing radiation, has no known harmful effects, and is particularly valuable for evaluating abdominal, pelvic or scrotal pain in children.

Preparation will depend on the type of examination. Ask your doctor if there are specific instructions for eating and drinking prior to the exam. Your child should wear loose, comfortable clothing and may be asked to wear a gown.

Ultrasound

Ultrasound imaging uses a transducer or probe to generate sound waves and produce pictures of the body's internal structures. It does not use ionizing radiation, has no known harmful effects, and provides a clear picture of soft tissues that don't show up well on x-ray images. Ultrasound is often used to help diagnose unexplained pain, swelling and infection. It may also be used to provide imaging guidance to needle biopsies or to see and evaluate conditions related to blood flow. It's also the preferred imaging method for monitoring a pregnant woman and her unborn child.

Mammography (Breast Imaging)

Mammography is a specific type of breast imaging that uses low-dose x-rays to detect cancer early—before women experience symptoms—when it is most treatable. Mammography plays a central part in the early detection of breast cancers because it can show changes in the breast up to two years before you or your physician can feel them. The American Medical Association (AMA) and the American College of Radiology (ACR) recommend annual mammograms for women over 40. The National Cancer Institute (NCI) adds that women who have a personal or family history of breast cancer should talk to their doctor about when they should begin screening.

What is Children's CT?

Computed tomography, more commonly known as a CT or CAT scan, is a diagnostic medical test that, like traditional x-rays, produces multiple images or pictures of the inside of the body.

The cross-sectional images generated during a CT scan can be reformatted in multiple planes, and can even generate three-dimensional images. These images can be viewed on a computer monitor, printed on film or transferred to a CD or DVD.

CT images of internal organs, bones, soft tissue and blood vessels typically provide greater detail than traditional x-rays, particularly of soft tissues and blood vessels.

CT scans may be performed on newborns, infants and older children.