MRgFUS FAQs Frequently Asked Questions: Ultrasound Imaging, Functional MRI, HIFU, MR Imaging and more

1. Are there contraindications for the ExAblate treatment?

In general, people who cannot go into an MRI will not be able to have the ExAblate treatment – this includes patients with metallic implants, patients who are claustrophobic, and patients who are allergic to the contrast agent, a dye used to see blood vessels during MR imaging. There are contraindications specific to each application and clinical protocol.

2. What does a patient experience during the ExAblate treatment?

During the 3-4 hour procedure, the patient lies on her stomach on a table inside an MRI scanner. Sedation and pain medication are given for relaxation. The patient is conscious throughout the procedure and in constant communication with the doctor.

First, MR images are taken to locate the tumor and surrounding anatomy and these images are used to plan treatment. Then individual pulses of focused ultrasound energy, called sonications, each lasting about 20 seconds, are directed to the fibroid. During each sonication, the tissue is heated to a temperature that results in necrosis, MR images are taken during each sonication showing the temperature reached allowing for real time control and monitoring of the treatment. Each treatment requires multiple sonications, depending on the size of the tumor. After the treatment, MR images with contrast agent are taken to determine the outcome of the treatment.

Following the procedure the patient rests for 1-2 hours until the sedation wears off and then returns home. Most people return to normal activity within 2-3 days.

3. How long does the treatment last?

Each exposure of focused ultrasound, or "sonication", ablates a volume in the tumor of about 6x6x25 mm. Therefore, multiple sonications are required to ablate the entire tumor, and the time required for a treatment depends on the tumor size. Treatments usually do not last longer than three hours, and multiple treatments may be required for large tumors.

4. What makes ExAblate better than other types of surgery for tumors?

ExAblate is performed as an outpatient procedure, with minimal post treatment pain. There are no needles or incisions, and no blood loss. For most indications, the patient is conscious during the entire ExAblate procedure. Furthermore, patients in the uterine fibroid pivotal trial who receieved the ExAblate treatment were able to return to normal activities quicker than patients who opted for surgery.

5. How many patients have been treated so far?

Over 2000 patients have been treated for uterine fibroids and more than 300 in other research applications such as breast cancer, pain palliation of bone metastases at ExAblate sites in the US and around the world. For more information on our clinical studies, click here. Look under Library on this website for publications related to ExAblate studies.

6. What is the difference between ExAblate, MRgFUS, FUS and HIFU ?

ExAblate is the name of InSightec`s device. MRgFUS stands for MR guided Focused Ultrasound Surgery – the technology used in the ExAblate. The ExAblate is the only device that has been FDA approved for treating fibroids using focused ultrasound. It is unique in that it uses magnetic resonance or MR images for guiding the treatment. FUS stands for Focused Ultrasound and HIFU stands for High Intensity Focused Ultrasound - these terms refer to the technique focusing of ultrasound (high frequency sound) waves.

7. What MRI systems does the ExAblate work with?

The ExAblate 2000 system is approved for commercial distribution for the uterine fibroids application and works exclusively with the GE 1.5T MR system. Additional applications, breast, bone metastases, liver, prostate and brain are under investigation on ExAblate research modules and are compatible with the GE 1.5T MR system and are under investigation with the GE 3T MR system.

8. How is focused ultrasound used to destroy tumors?

Similar to the phenomenon that occurs when a magnifying glass focuses light energy, focused ultrasound can induce heating at the focal point of the ultrasound beam. If the intensity at the focal point is sufficient to heat soft tissue in the tumor beyond a certain threshold, necrosis (or cell death) occurs. The threshold for 100% necrosis is determined by the exposure time and temperature of the heating. At 57 degrees, it takes only about 1 second to achieve 100% necrosis.