MRI Scan Part-4

MRI Scan At A Glance

• 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.

MRI scan Part-3

How does a patient prepare for an MRI scan and how is it performed?

All metallic objects on the body are removed prior to obtaining an MRI scan. Occasionally, patients will be given a sedative medication to decrease anxiety and relax the patient during the MRI scan. MRI scanning requires that the patient lie still for best accuracy. Patients lie within a closed environment inside the magnetic machine. Relaxation is important during the procedure and patients are asked to breathe normally. Interaction with the MRI technologist is maintained throughout the test. There are loud, repetitive clicking noises which occur during the test as the scanning proceeds. Occasionally, patients require injections of liquid intravenously to enhance the images which are obtained. The MRI scanning time depends on the exact area of the body studied, but ranges from half an hour to an hour and a half.

How does a patient obtain the results of the MRI scan?

After the MRI scanning is completed, the computer generates visual images of the area of the body that was scanned. These images can be transferred to film (hard copy). A radiologist is a physician who is specially trained to interpret images of the body. The interpretation is transmitted in the form of a report to the practitioner who requested the MRI scan. The practitioner can then discuss the results with the patient and/or family.
Future
Scientists are developing newer MRI scanners that are smaller, portable devices. These new scanners apparently can be most useful in detecting infections and tumors of the soft tissues of the hands, feet, elbows, and knees. The application of these scanners to medical practice is now being tested.

Pictures of an MRI of the spine

This patient had a herniated disc between vertebrae L4 and L5. The resulting surgery was a discectomy
Picture of herniated disc between L4 and L5

Cross-section picture of herniated disc between L4 and L5

MRI scan Part-2

What are the risks of an MRI scan?

What are the risks of an MRI scan?

An MRI scan is a painless radiology technique that has the advantage of avoiding x-ray radiation exposure. There are no known side effects of an MRI scan. The benefits of an MRI scan relate to its precise accuracy in detecting structural abnormalities of the body.
Patients who have any metallic materials within the body must notify their physician prior to the examination or inform the MRI staff. Metallic chips, materials, surgical clips, or foreign material (artificial joints, metallic bone plates, or prosthetic devices, etc.) can significantly distort the images obtained by the MRI scanner. Patients who have heart pacemakers, metal implants, or metal chips or clips in or around the eyeballs cannot be scanned with an MRI because of the risk that the magnet may move the metal in these areas. Similarly, patients with artificial heart valves, metallic ear implants, bullet fragments, and chemotherapy or insulin pumps should not have MRI scanning.
During the MRI scan, patient lies in a closed area inside the magnetic tube. Some patients can experience a claustrophobic sensation during the procedure. Therefore, patients with any history of claustrophobia should relate this to the practitioner who is requesting the test, as well as the radiology staff. A mild sedative can be given prior to the MRI scan to help alleviate this feeling. It is customary that the MRI staff will be nearby during MRI scan. Furthermore, there is usually a means of communication with the staff (such as a buzzer held by the patient) which can be used for contact if the patient cannot tolerate the scan.

MRI scan Part-1

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. In the head, trauma to the brain can be seen as bleeding or swelling. Other abnormalities often found include brain aneurysms, stroke, tumors of the brain, as well as tumors or inflammation of the spine.
Neurosurgeons use an MRI scan not only in defining brain anatomy but in evaluating the integrity of the spinal cord after trauma. It is also used when considering problems associated with the vertebrae or intervertebral discs of the spine. An MRI scan can evaluate the structure of the heart and aorta, where it can detect aneurysms or tears.
It provides valuable information on glands and organs within the abdomen, and accurate information about the structure of the joints, soft tissues, and bones of the body. Often, surgery can be deferred or more accurately directed after knowing the results of an MRI scan.

Ascites Part-4

What is the outlook (prognosis) for ascites?

The outlook on ascites primarily depends on its underlying cause and severity.
In general, the prognosis of malignant ascites is poor. Most cases have a mean survival time between 20 to 58 weeks, depending on the type of malignancy as shown by a group of investigators.
Ascites due to cirrhosis usually is a sign of advanced liver disease and it usually has a fair prognosis with a 3-year survival rate of about 75%.
Ascites due to heart failure has a fair prognosis as the patient may live years with appropriate treatments.

Ascites part-3

What are the complications for ascites?

Some complications of ascites can be related to its size. The accumulation of fluid may cause breathing difficulties by compressing the diaphragm and formation of pleural effusion.
Infections are another serious complication of ascites. In patients with ascites related to portal hypertension, bacteria from the gut may spontaneously invade the peritoneal fluid (ascites) and cause an infection. This is called spontaneous bacterial peritonitis or SBP. Antibodies are rare in ascites and, therefore, the immune response in the ascitic fluid is very limited. The diagnosis of SBP is made by performing a paracentesis and analyzing the fluid for the number of white blood cells or evidence of bacterial growth.
Hepatorenal syndrome is a rare, but serious and potentially deadly (average survival rates range from 2 weeks to about 3 months) complication of ascites related to cirrhosis of the liver leading to progressive kidney failure. The exact mechanism of this syndrome is not well known, but it may result from shifts in fluids, impaired blood flow to the kidneys, overuse of diuretics, and administration of contrasts or drugs that may be harmful to the kidney.

Can ascites be prevented?

The prevention of ascites largely involves preventing the risk factors of the underlying conditions leading to ascites.
In patients with known advanced liver disease and cirrhosis of any cause, avoidance of alcohol intake can markedly reduce the risk of forming ascites. Nonsteroidal antiinflammatory drugs (ibuprofen [Advil, Motrin, etc.]) should also be limited in patients with cirrhosis as they may diminish the blood flow to the kidneys, thus, limiting the salt and water excretion. Complying with dietary salt restrictions is also another simple preventive measure to reduce ascites.

Ascites Part-2

What is the treatment for ascites?

The treatment of ascites largely depends on the underlying cause. For example, peritoneal carcinomatosis or malignant ascites may be treated by surgical resection of the cancer and chemotherapy, while management of ascites related to heart failure is directed toward treating heart failure with medical management and dietary restrictions.
Because cirrhosis of the liver is the main cause of ascites, it will be the main focus of this section.

Diet

Managing ascites in patients with cirrhosis typically involves limiting dietary sodium intake and the use of diuretics (water pills). Restricting dietary sodium (salt) intake to less than 2 grams per day is very practical, successful, and widely recommended for patients with ascites. In majority of cases, this approach needs to be combined with the use of diuretics as salt restriction alone is generally not an effective way to treat ascites. Consultation with a nutrition expert in regards to daily salt restriction can be very helpful for patients with ascites.

Medication

Diuretics increase water and salt excretion from the kidneys. The recommended diuretic regimen in the setting of liver related ascites is a combination of spironolactone (Aldactone) and furosemide (Lasix). Single daily dose of 100 milligrams of spironolactone and 40 milligrams of furosemide is the usual recommended initial dosage. This can be gradually increased to obtain appropriate response to the maximum dosage of 400 milligrams of spironolactone and 160 milligrams of furosemide, as long as the patient can tolerate the dose increase without any side effects. Taking these medications together in the morning is typically advised to prevent frequent urination during the night.

Therapeutic paracentesis

For patients who do not respond well to or cannot tolerate the above regimen, frequent therapeutic paracentesis (a needle carefully is placed into the abdominal area, under sterile conditions) can be performed to remove large amounts of fluids. A few liters (up to 4 to 5 liters) of fluid can be removed safely by this procedure each time. For patients with malignant ascites, this procedure may also be more effective than diuretic use.

Surgery

For more refractory cases, surgical procedures may be necessary to control the ascites. Transjugular intrahepatic portosystemic shunts (TIPS) is procedure done through the internal jugular vein (the main vein in the neck) under local anesthesia by an interventional radiologist. A shunt is placed between the portal venous system and the systemic venous system (veins returning blood back to the heart), thereby reducing the portal pressure. This procedure is reserved for patients who have minimal response to aggressive medical treatment. It has been shown to reduce ascites and either limit or eliminate the use of diuretics in a majority of cases performed. However, it is associated with significant complications such as hepatic encephalopathy (confusion) and even death.
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