National Geographic : 2007 Feb
PICTURING HEART DISEASE An angiogram reveals an abrupt closure-referred to as a "widow maker"-in a critical coronary artery (below left). This technique uses a catheter, dye, and x-rays to navigate and study blood vessels. In a second angiogram, after a stent like the one shown opposite has been inserted, blood flow is restored (below right). With a different technique, intravascular ultrasound, doctors are able to examine the inside of a vessel in cross section (opposite, left and right). Plaque (yellow) constricts blood flow (red). Once a stent has been inserted and the wall propped open, blood flows more freely. Says Dr. Paul Yock of Stanford University: "Ultrasound helps us completely expand the stents so they have a better chance of staying open."