A proper diagnosis is always a part of great therapy. However, it can also be beneficial to be able to quickly respond to changes during a treatment. One example of this is the treatment of uterine myomas. Since recently, female patients at the University Hospital Bonn are treated using so-called high-intensity focused ultrasound, HIFU in short. The advantage: each myoma is illustrated in detail before it is destroyed. Professor Holger Strunk explains this procedure.
Professor Strunk, for the past year, you have used so-called high-intensity focused ultrasound to treat female patients with myomas. How does this work?
Holger Strunk: The treatment with high-intensity focused ultrasound is a method that permits a targeted, non-invasive treatment from outside the body by passing through the intact skin. The prerequisite for this treatment is an exact guidance that is done with our device using ultrasound. It does not only illustrate the myoma that needs to be treated but also counterbalances diaphragmatic excursions and movements during the intervention. Before the procedure, a detailed diagnostic investigation takes place even if we see the myomas during the treatment. The size, location and number of myomas are especially important to decide on a treatment option. That’s why we perform an MRI and a sonogram. The female patients need to visit our gynecology department and we suggest the best suited individual treatment option together with the gynecologist. When an HIFU treatment is generally possible, we invite the patients to conduct a so-called simulation. In this case, we check whether we can see the myoma using the ultrasound in a face-down position. The ultrasound device we use for the treatment has a water basin that contains a special transducer with an acoustic lens. It focuses the ultrasound waves at one point in the body to generate heat. In doing so, the myomas are being destroyed one by one. The patient lies comfortably in a face-down position during the treatment on a table with an opening in the middle under which the water basin is located. The patient is coupled to the water so to speak since air destroys the ultrasound.
Is this treatment painful?
Strunk: Yes. Although opinions differ when it comes to uterine myomas, it is generally painful because tissue is being destroyed. This is why the patients receive pain relievers and sedatives during the treatment and are being monitored by an anesthesiologist. The treatment typically takes between two and four hours, depending on the size, number and location of the myomas.
How do you proceed if the patient moves during the treatment?
Strunk: Since we are with the female patient in the same room during the entire treatment and are able to see the area thanks to the ultrasound, we are able to respond immediately. We need to readjust to rechart the targeted area.
Can you explain the difference between ultrasound-guided versus MRI-guided HIFU therapy?
Strunk: The difference is in the guidance; the treatment is essentially the same. Prior to the treatment, the myomas are located and illustrated. This illustration can either be done with ultrasound, which we use, or with magnetic resonance tomography. An ultrasound device is somewhat easier to operate and has one distinct advantage: everything you see with the ultrasound can also be treated. If an intestinal loop is in front of the myoma, for example, you can see it on the ultrasonic scan but not necessarily with an MRI. In addition, with the ultrasound, we can pinpoint what we are treating, what is changing or whether something shifts, for instance due to the patient’s respiration. However, the advantage of an MRI is that the achieved temperature in the affected area can be measured. This is not possible with ultrasound. In this case, we use other parameters to determine the treatment success.
Urologists have already been using HIFU devices to treat prostate cancer. Why have you now just discovered their use for radiology?
Strunk: Urologists use significantly smaller devices and other sound waves. We are able to treat considerably larger areas. Yet indeed, this method has already been used in China for the past 15 years. It has become an established method there. Here, we are still in the early stages, also as it pertains to patients with pancreatic cancer, for example, since in palliative care, this method can at least contribute for patients to have significantly less pain at an advanced stage of their disease.