MRgFUS Screening/Baseline Testing Part 1

I spent most of the day today at Sunnybrook Hospital undergoing the first of two days of screening and baseline testing for my upcoming Magnetic Resonance-guided Focused Ultrasound Surgery (MRgFUS) for depression.  It was an interesting experience and I got to see first hand where I will be having the surgery and where I will be staying for the night afterward.

The day started out with a visit with the neurosurgeon for the study in which I am taking part, Dr. Nir Lipsman.  He reviewed the procedure with me and went over the possible side effects.  I will be having a bilateral anterior capsulotomy, in which they create lesions in the anterior limb of the internal capsule.  This connects the frontal lobes to the emotional centres of the brain, including the amygdala and hippocampus.  It is this area that they believe is overactive in depressed people.  They have to tell you about every possible side effect that they could conceive of for this surgery, so it makes it sound a little frightening.  For example, there is the risk that they could cause a lesion outside of the planned treatment area resulting in a serious neurological deficit or even death.  The doctor was very good and put this all into context.  The chances of anything bad happening are less than if I had chosen to do Deep Brain Stimulation (DBS), which was my other option.

I also got a little bit more information about the frame that they will be bolting to my head to keep it immobile during the surgery and to fit the helmet containing the array of 1,000 tansducers, which convert electrical energy into sound energy and focus the ultrasound waves onto specific parts of the brain.  The frame will actually be bolted on to my skull.  The bolts will go through the skin and go all the way to the skull.  This is done to minimize movement, which could cause them to create a lesion outside of the planned treatment area.  However, I will have four holes in my skin on my head that will take a few months to heal.  Here is a picture of the first patient being treated for depression getting fitted with the frame (and, yes, I will need to shave my head too).

Then I had an MRI so that they can take a look at my brain before doing the operation.  This is an important step as abnormalities in the brain could cause me to be disqualified from receiving this operation.  For example, Dr. Lipsman said that a recent candidate had to be disqualified because it was discovered that he had a blood vessel going right through the area that they needed to create the lesions.

Following that I did some psychiatric scales to measure the level of depression at which I am currently.  Seeing as this is a study, they will be repeating these scales at regular intervals to determine if the surgery is having an effect on my level of depression.

I then had a CT scan to determine my skull density.  This is an important step as the density of the skull can impact the effectiveness of the treatment.  Depending on the density of the skull, the ultrasound waves may bounce off of the skull and make it impossible to create a lesion.  Alternatively, they may only be able to create a lesion on one side of my brain and not the other.  If they cannot perform the surgery for this reason, then there is the option of choosing to do a Gamma Knife Radiation Surgery (GKRS) to create the lesions.  This isn't preferred though because they can't guide it with an MRI machine and it exposes the patient to harmful radiation.

I finished the day off by having some bloodwork done that is required to make sure that I am healthy enough to have the surgery.  Next week I will have another day at the hospital as I meet with the anesthesiologist, have a PET scan performed and do neuropsychological testing.