Advances in the diagnosis of cerebrovascular pathology

Abstract

Up to now, digital subtraction angiography (DSA) has been considered the gold standard for the detection of cerebrovascular pathology. Two noninvasive angiographic modalities have experienced an impressive recent improvement: magnetic resonance angiography (MRA) and three-dimensional computed tomographic angiography (CTA). With the latest modifications in postprocessing, the resolution of MRA has become similar to that of DSA. MRA can accurately delineate vessels less than 1 mm and aneurysms equal to or greater than 3 mm in diameter. Three-dimensional reconstructionfrom MR images can also be used for planning the surgery of cerebrovascular pathology. Three-dimensional CTA has greater resolution than MRA and has excellent correlation with DSA. CTA is extremely sensitive for the detection of cerebral aneurysms: Compared with DSA its sensitivity is about 97% and its specificity 100%. Although DSA is an invasive procedure, it still possesses greater resolution than MRA and CTA. In the hands of the skilled neuroradiologist, it carries a low risk and is the best method for the evaluation of cross-flow or vascular reserve and for postoperative control. MRA and CTA can replace DSA for the depiction of ruptured or unruptured cerebral aneurysms. As a result of the widespread use of noninvasive angiographic methods, an increasing number of unruptured aneurysms will be diagnosed. It is currently accepted that unruptured aneurysms greater than 5 mm in diameter should be surgically clipped. The wrapping technique is not generally considered to be an effective treatment of cerebral aneurysms.