From December 2008 to February 2010:
- 8 patients (mean age,
age range 46-52) with symptomatic uterine fibroids free of other pelvic pathology that required surgical intervention
- all patients underwent HIFU
- patients underwent MRI before and 6 months after treatment
MAGNETIC RESONANCE IMAGING (MRI):
- multiplanar capacity and excellent soft tissue contrast resolution reflecting pathology
- 1.5-T MRI scanner and a multi-phased array coil (cardiac,
- T2-weighted FSE in the sagittal,
axial; coronal planes when needed
- Dynamic-contrast study (FSPGR)
- DW imaging (b value= 500 sec/mm2) images in the axial and sagittal planes
MRI sequences parameters (Table 1)
For each fibroid the following parameters were assessed:
- percentage of intralesional necrosis
- ADC value
- Percentage of contrast enhancement
- pre and post-treatment data were compared
DIFFUSION WEIGHTED IMAGING (DWI):
Exploits the random motion of water molecules,
a phenomenon otherwise known as Brownian motion or free diffusion.
Within biologic tissue,
the movement of water is impeded by interaction with tissue compartments,
cell membranes and intracellular organelles.
Water movement in tissues may be:
The apparent diffusion coefficient (ADC) relates to the molecular translation movement of water molecules:
- decreased ADC values therefore correlate with increased tumor cellularity and total nuclear area,
which act to restrict water diffusion
- an increase of ADC reflect the liquefactive necrosis,
low cellularity 
The mean ADC values of the lesion were measured in a circular region of interest (ROI) in one representative region as large as possible within the lesions from ADC maps on the Workstation.
DYNAMIC CONTRAST STUDY:
Contrast-enhanced MRI reflects the fibroid vascularity and allows to evaluate if the leiomyoma targeted for treatment is well vascularized (perfused),
because leiomyomas with large areas of degeneration (no perfusion) would not benefit from HIFU treatment .
HIGH INTENSITY FOCUSED ULTRASOUND (HIFU):
The HIFU technique is a new,
non-invasive high precision procedure,
considered as a valid alternative to surgery in the treatment of uterine fibroids.
Ultrasound has two unique properties which allow it to be used for the ablation of solid tumors:
- it passes harmlessly through soft tissues
- may deposit enough energy in the focal region to cause localized tissue ablation.
The fine balance between transmission and deposition of energy is utilized to ablate leiomyomas in a non-invasive way.
Tissue temperature within the local region is instantly raised to 65-100°C during first-second of HIFU exposure; coagulation necrosis is therefore immediately induced in the tumor.
Another important mechanism,
through which cellular necrosis is obtained is an inert cavitation process resulting cell membranes rupture by jet phenomenon.
Small tumor blood vessels of less than 2 mm diameter can be completely destroyed by HIFU .
Leiomyoma ablation is therefore caused by ischemic and mechanical-hyperthermic injury.
The real benefit of this technique is to strike the target tissue with precision while sparing the normal surrounding structures [4,