Therapeutic MRI-guided High Intensity Focused Ultrasound ablation of uterine fibroids

Uterine leiomyomas are the most common benign tumor in pre-menopausal women.
Symptomatic fibroids impact health and well-being of the female including lost
work hours and reduced quality of life. Fibroids occur in 20-50% of women over
30 years of age.
When medical treatment fails, surgical treatment is an option. However, this
has a substantial risk of complications and has a long recovery. Minimal
invasive treatments have the advantage of a quick recovery and the risk of
complications is low.

High Intensity Focused Ultrasound is a completely non invasive treatment for
fibroids, recently cleared by the FDA. MRI guided High Intensity Focused
Ultrasound (MRgHIFU) used ultrasoundwaves to locally ablate fibroid tissue.
Results in relieving symptoms are promising. Treatment is well tolerated well
and the recovery period is short.

In this study we want to evaluate the safety, technical efficiency, and volume
treatment capabilities of the Philips MR guided HIFU system in the treatment of
patients with symptomatic uterine fibroids. This information is required for CE
labelling of the Philips MR-HIFU system. The importance of this study is that
it offers a non-invasive, uterus sparing procedure for the treatment of uterine
fibroids in pre- and perimenopausal women.

A prospective, multi-center, single arm, non-randomized study.

In MRI-guided High Intensity Focused Ultrasound (MRgHIFU), the ultrasound
generated by the transducer is focused into a small focal tissue volume at
specific target locations. During treatment, the beam of ultrasound energy
penetrates through soft tissue and causes localized high temperatues (50-70
degrees) for a few sexonds within the target. This produces well defined
regions of protein denaturation, irreversible cell damage, and coagulative
necrosis within the focal region. Multiple ultrasound exposures are necessary
to ablate the targeted tissue. Tight focusing is designed to limit the abaltion
the the targeted location.

Applying HIFU energy to a fibroid requires treatment planning, targeting of the
ultrasound beam to desired locations and monitoring of the energy delivery. MR
imaging provides anatomical details and helps with procedure planning and
treatment targeting, including 3D planning and means of measuring the
temperature increase generated by HIFU. In addition, MRI provides non-invasive
metrics for quantifying the energy/dose delivered to the treatment zone in
real-time. Based on these validated MR-HIFU principles, Philips adds volumetric
heating with automated feedback approach to provide real-time tissue
temperature mapping in multiple planes, steering of the focal point via
real-time feedback, and control of the temperature delivering an optimal
thermal dose to the target location.

Preparation phase:
-questionnaires symptoms and quality of life
-MRI with contrast in prone position
-blood tests and pregnancy test

Treatment day:
-insertion peripheral infusion line and urinary catheter
-administration conscious sedation during treatment
-MRgHIFU treatment (takes about 3 hours, patient lies in prone position in MRI
bore)
-post-treatment MRI with contrast
-recovery of sedation (approximately 2 hours), then discharge

After treatment:
-patient diary about discomfort, pain, and pain medication
-1 months after treatment questionnaire about symptoms and quality of life
-MRI with contrast after 1 months

Risks of MRgHIFU:
-Potential complications after the HIFU procedure are nausea, pain, abdominal
tenderness, and leg and buttock pain.
-Less potential complications are swelling, urinary difficulty (urinary tract
infection), abdominal cramping and internal tissue thermal injury.
-Very rarely seen complications are first degree skin burns, sciatic nerve
damage, pain not reacting to drugs, vomiting, above baseline vaginal bleeding,
injury to abdominal and pelvic organs (bladder, uterus, intestine) adverse drug
reactions (gadolinium), urinary tract infection, fever due to infection, other
infection. These complications are very rare.
-Unlikely complications are 2nd and 3rd degree skin burns.

Risks of gadolinium based contrast:
-non serious adverse events: head ache and paresthesia
-1-10%: nausea, vomiting, skin reaction (erythema/itch)
-rare: anaphylactic shock, nefrogenic systemic fibrosis (NSF)