Types of iMRI Procedures
Invasive iMRI Procedures
Percutaneous Renal Cryoablation, i.e. Freezing Kidney Tumors
Norton Hospital has become one of only four hospitals in the U.S.* to be able to offer patients who have kidney tumors a cutting-edge minimally invasive, MR guided, alternative to traditional surgery.
The procedure involves inserting up to four thin probes into the tumor. The probes use argon gas to freeze the tumor, literally turning it into an ice ball with temperatures as low as - 170 degrees Celsius. Alternately, using helium gas, the probes warm up to 70 degrees Celsius to gradually thaw the tumor. The freezing and thawing process is repeated. The tumor is not removed from the body. Instead, the patient's immune system attacks and dissolves the dead cells. The average procedure takes about 90 minutes to perform.
Patients are usually admitted to the hospital overnight for observation and seen for follow up. Patients usually go home with a small puncture site or sites, and a small dressing (bandage).
For more information about the Freezing Kidney Tumors procedure, please call (502) 629-1234.
* Statistic provided by Marie Molnar-Hammond, Oncura Company 03/30/04
Radio Frequency Ablation (RFA) of Liver Tumors, i.e. Heating Liver Tumors
Norton Hospital is one of less than a dozen hospitals in the country where MR-guided radio frequency ablation (RFA) of liver tumors is performed.
The preferred treatment for patients with liver tumors is surgical removal, also called resection. However, conventional resection often is not possible when a patient has multiple tumors in the liver or if a patient has cirrhosis or other serious medical problems.
Traditionally, liver tumor removal required surgery. Today, physicians offer patients less invasive treatment options such as RFA. Using this technique, physicians insert a very small needle into the tumor and heat it using radio frequency, similar to microwaves, allowing destruction of the liver tumors while sparing the majority of normal liver tissue.
RF ablation uses an array of wires, guided through a needle, that spread out into the tumor in a starburst form. Some of these wires contain a tiny thermometer that measures the temperature of the surrounding tissue. These wires are attached to a generator that produces alternating current in the controllable range of radio waves. The alternating current heats the tumor cells in excess of 100 degrees Celsius, destroying them. The tumor is not removed from the body. Instead, the patient's immune system attacks and dissolves the dead cells.
RFA can be performed as an open operation, but increasingly is performed using minimally invasive approaches including laparoscopy, CT-guidance and MR-guidance. Norton Hospital is the only hospital in the region where the procedure can be performed in an iMRI.
The procedure is performed in the iMRI percutaneously (inserting the probe through a needle and through the skin). With the percutaneous method, the patient is often able to go home within 24 hours with only a needle puncture site.
For more Information about the Heating Liver Tumors procedure, please call (502) 629-1234.
When MRI was first introduced it dramatically altered neurosurgery by showing exactly where abnormalities are, allowing doctors to plan precise surgeries. MRI's acquired the day after the operation were used to judge the success of the surgery. The iMRI takes this to another level by providing images at multiple steps during the operation.
With the iMRI, the entire surgery is performed in the magnet and the patient's head stays in the imaging "sweetspot" the entire time. A surgeon can stand on either side of the patient and the surgeons can request an image at any time. Neither the surgeons nor the patient needs to move for the images to be acquired, and both surgeons are able to immediately view the images while standing in the magnet at the patient's side. The surgeons can use the information provided by the newest images to approach any remaining tumor via the safest possible path and remove it. Images can be acquired repeatedly during the procedure until the procedure is completed. The iMRI also plays a critical role in cases where the tumor looks and feels just like normal brain. In those cases the black and white map of normal tissue and tumor that the iMRI provides helps the surgeon remove tumor that otherwise may have been left behind. Surgery in the iMRI can also be safer because the MR images confirm that there is no bleeding, which is a major safety concern in neurosurgery.
For more Information about Neurosurgery, please call (502) 629-1234.
Removal of Orbital Tumor
One case that demonstrates the benefits possible with the iMRI was a case of a 22-month old child with a tumor behind her eye. The child was initially treated in the regular OR, but after a very long surgery the tumor could not be identified. The surgery was significant and required a one-week postoperative recovery in the hospital. Subsequently, the child was brought to the iMRI and an approach to the tumor going through the eye socket and under the eyeball was employed. The MR image helped the surgeon identify the tumor and resect it without damaging the fine network of nerves and muscles behind the eye that control the eye movement. The child went home the day following the surgery in the iMRI with seven stitches at the corner of her eye.
For more Information about Orbital Tumor procedure, please call (502) 629-1234.
MR-Guided Joint Reduction - Closed Hip Reduction
Occasionally children are born with dislocated hips. The head of the femur needs to be in the hip socket in order for them both to develop normally so that both the head of the femur and the hip socket are round and the child has full range of motion. In most cases, a special sling called a Pavlik harness is used to continually push the head of the femur into the hip socket, but for a limited number of children the sling is inadequate. The normal procedure for these children is to put the head of the femur in the hip socket under a general anesthetic, then apply a cast to hold the bones in place. The procedure is done in the OR under general anesthesia and uses X-ray fluoroscopy, with a dye injection, to monitor the procedure. Following the surgery, the child is imaged with MR or CT to verify that the bones remain in place. Sometimes the hips re-dislocate in the cast, because the significant amount of fat typical with newborns makes casting their bones difficult. When this happens, the cast is cut off and the whole procedure starts all over again.
The iMRI allows the procedure to be done quickly and easily. The MR images provide excellent visualization of the bones and the soft tissue, eliminating the dye injection and the radiation dose to the child's genitals. Images can be acquired at multiple stages during the procedure, so if the head of the femur slips out of the hip socket it can be immediately put back in. The entire procedure is done in the iMRI, so there is no need to transport the anesthetized child from the OR to the Radiology Department.
For more Information about MR-Guided Joint Reduction - Closed Hip Reduction procedure, please call (502) 629-1234.