The ultrasound therapy can be offered to any patient with symptomatic fibroids with menometrorrhagia or compression syndrome and asymptomatic patients who wish to become pregnant for whom the fibroids may be causing infertility or miscarriage or problems during pregnancy and/or childbirth.
From a clinical point of view, we try to assess symptoms objectively through a specific questionnaire, The Uterine Fibroid Symptom and Quality of Life (UFS-QOL),26,27 which not only discriminates between normal controls and patients with fibroids, but also rates the severity of the symptoms.
MRI with contrast is essential to provide information on the size, location and number of fibroids, T2 signal type, vascularisation and presence of adenomyosis or abdominal scars. It also allows us to calculate the depth of the lesions to be treated, since this will determine the type of transducer to be used or even, in some cases, that the fibroids are not treatable as they are outside the scope of the ultrasound waves.
Some of these factors can therefore be limitations to the use of HIFU.
Size and location of the fibroids
The majority of the published studies have treated fibroids smaller than 10 cm. Smart demonstrated that prior administration of GnRH analogues allowed for treatment of larger fibroids in addition to increasing the efficacy of ablation, particularly in highly vascularised fibroids (Fig. 4). For treatment to be adequate, part of the fibroid has to be in the wall of the myometrium, and so treatment of pedunculated subserosal fibroids is not recommended. Large, submucosal fibroids can be treated with good results (Figs. 5 and 6).
Number of fibroids The number of fibroids that can be treated is more in relation to their size and the amount of time necessary for treatment. Most studies treated 4 or fewer, although it is possible to treat up to 10 (Fig. 7).
T2-weighted magnetic resonance signal
Highly vascularised fibroids respond poorly to FUS therapy and have a lower non-perfused volume ratio post-ablation. Most Funaki type III fibroids are highly vascularised.Abdomen and pelvis
Abdominal scarring can interfere with and distort the therapeutic ultrasound beam. As this increases the risk of burns to the skin, the scars need to be avoided.
Patients with previous surgery on the uterus, including myomectomy, are more likely to have fixed intestinal adhesions, which would make them susceptible to intestinal damage. Various techniques have been described to prevent these complications: abdominal compression with balloon; hyperdistension of the bladder to keep the intestines away from the therapeutic ultrasound beam (Fig. 9). In any event, there have been no reported cases of intestinal injury in HIFU treatment of fibroids.