Can noninvasive studies replace conventional angiography in the preoperative evaluation of carotid stenosis?

Most articles in 1995 demonstrated a sensitivity of 100% and specificities of 90% to 98% in detecting carotid bifurcation stenosis using a combination of MR angiography and ultrasonography, reserving conventional angiography for cases of disparate stenosis with the noninvasive studies. Multiple reviews concluded that noninvasive studies were less morbid than conventional angiography when taking into account the risks of conventional angiography and surgery as well as the morbidity associated with unnecessary surgery (false-positive noninvasive study) or withholding indicated surgery (false-negative noninvasive study). Thus, the current literature suggests that non-invasive studies have indeed reached a point where they can replace conventional angiography in the preoperative evaluation of carotid bifurcation stenosis. It is paramount that each imaging center review its own sensitivity and specificity in detecting surgically significant carotid stenosis with noninvasive studies. High sensitivity and specificity in diagnosing percent carotid stenosis with noninvasive studies can occur today with routine imaging equipment, but it takes a great deal of effort and dedication on the part of the imaging center.