A recent study involving 141 patients with suspected pulmonary embolism suggests that magnetic resonance angiography (MRA) may actually be safer than pulmonary angiography, the conventional technique for spotting blood clots (embolism).

MRA is now increasingly being used to diagnose a number of chest disorders, and the Dutch-English team of researchers who carried out this study says MRA picked up evidence of pulmonary embolism missed by the usual angiography.

Angiograms involve injecting a radioactive dye into the blood vessel through a catheter to show up blockages on an X-ray. In contrast, MRA uses a magnetic field and pulses of radiowave energy to produce pictures of soft body tissues. It’s less invasive, easier to perform and accurate.

MRA also has an advantage over other diagnostic scanning techniques in that it shows better tissue differentiation and provides images in multiple planes - in fact, in 3-D - yet it doesn’t use radiation and enables veins to be viewed.

The big minus of its use has been that patients had to endure long scanning times while holding their breath, and results were flawed if patients moved during the process. But now, MRA can scan faster to reduce scanning time and take in more detail in a single sweep (Lancet, 2002; 359: 1643-7).