Great advances have been made in treating blockages in the arteries of the brain using angioplasty to widen the narrowed artery and a stent to hold the artery open.
However, in-stent stenosis, or a re-blockage of the artery within the stent due to scar tissue or blood clots, is estimated to occur in up to 30 percent of patients and can cause a stroke or death.
A new study by researchers at Rush University Medical Center has found that quantitative magnetic resonance angiography (QMRA) is a promising screening tool to detect in-stent stenosis with high sensitivity and specificity. The study is available early online and will appear in the March issue of Stroke: Journal of the American Heart Association .
Noninvasive imaging such as magnetic resonance angiography (MRA) and computerized tomography angiography often can not provide an accurate diagnosis of in-stent stenosis because the image is distorted by the reflection of metal stents or coils. Due to this problem, conventional angiography continues to be used routinely after stent placement to screen for in-stent stenosis. However, conventional angiography requires threading a catheter from the arteries in the groin to the brain and carries a slight risk of neurological and non-neurological procedural complications.
Quantitative MRA (QMRA) is a flow analysis system that uses traditional MRI to produce a 3D model of the vasculature and quantify vessel blood flow. The procedure is completely non-invasive and no contrast is needed. Recent studies have established this technology's use in the measurement of arterial blood flow in various cerebrovascular conditions and carotid bypass surgery; however, this is the first study to assess the use of QMRA in the detection of intracranial in-stent stenosis.