Improving CT Scans, Treating MS: Notes from an IR Conference

I am slightly obsessed with the topic of radiation exposure, since I have covered radiation overdoses from CT scans on this blog and written about radiation issues in post-earthquake Japan and treating radiation injuries for Medscape. So I was interested to learn about efforts to decrease radiation exposure in patients when I stopped by the Society of Interventional Radiology's annual meeting in San Francisco last week.

Interventional radiologists (IRs) perform many minimally-invasive procedures, such as placing stents in arteries to increase blood flow or delivering targeted chemotherapy to a tumor. These procedures can often replace more invasive and riskier open surgeries. But the flip side of this medical progress is that some of the imaging technologies used to guide these procedures, specifically CT scans and X-rays, expose patients to ionizing radiation, the type of radiation that can harm DNA. 

A poster at the session explained that CT scans are a key source of radiation exposure in the U.S. This exposure can be decreased by adjusting the CT scanner and basing the dose on the patient's BMI, explained author J. Collins et al. ("A Practical Guide to CT Dosimetry for the Interventional Radiologist").

Another intriguing development covered at the conference: the use of angioplasty (widening a narrowed blood vessel) to treat multiple sclerosis. Angioplasty can clear blockages in veins that might contribute to MS symptoms. Some patients who were studied reported that their symptoms improved after the procedure. The course of MS can be so fickle, though, that it's hard to tell whether symptoms improved or the disease simply relapsed for a while, reporter Laird Harrison explained in a WebMD article on the topic ("Treating Clogged Veins Improves MS, Study Says"). The press release about the procedure from the Society of Interventional Radiology is available online.

Can Stem Cells Stop MS?

Later this year, a small clinical trial will begin in Europe to test the use of stem cells to manage or possibly reverse the progress of multiple sclerosis, a disease in which a patient's immune system attacks the myelin sheath that protects nerve cells from damage. The disease tends to first strike when a patient is in their 20s and 30s, and it causes a range of symptoms (which vary widely by patient) such as fatigue, numbness, and balance problems.

For the trial, stem cells will be taken from patients' bone marrow and then injected into their blood, Pallab Ghosh reported for BBC News Health ("Doctors begin major stem cell trial for MS patients"). Promising earlier studies have used these stem cells to "retrain" the patient's immune system not to attack the myelin sheath.

Multiple sclerosis is more common in areas farther from the equator, such as the UK and the northern United States, as this fascinating geographic map of cases illustrates. The incidence of MS appears to be increasing, particularly among women, with some blaming the Western diet and vitamin D deficiency.

Ghosh points out that this trial also aims to address the problem of medical tourism among MS patients, who sometimes seek expensive and unproven stem cell treatments outside the UK. The trial will provide scientific evidence of the efficacy of stem cell treatment.

The phase II trial begins at the end of the year, investigating whether stem cell treatment is effective in human subjects and what side effects it might cause. The trial includes 150 patients and is predicted to take five years, with a possible phase III trial (comparing stem cell treatment to standard MS treatments) to follow before any new treatment can be brought to market.