RT Journal Article
SR Electronic
T1 A Standardized Method for Measuring Intracranial Arterial Stenosis
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP 643
OP 646
VO 21
IS 4
A1 Samuels, Owen B.
A1 Joseph, Gregg J.
A1 Lynn, Michael J.
A1 Smith, Harriet A.
A1 Chimowitz, Marc I.
YR 2000
UL http://www.ajnr.org/content/21/4/643.abstract
AB BACKGROUND AND PURPOSE: Atherosclerosis of the major intracranial arteries is an important cause of ischemic stroke. We established measurement criteria to assess percent stenosis of a major intracranial artery (carotid, middle cerebral, vertebral, basilar) and determined the interobserver/intraobserver agreements and interclass/intraclass correlations of these measurements.METHODS: We defined percent stenosis of an intracranial artery as follows: percent stenosis = [(1 − (Dstenosis/Dnormal))] × 100, where Dstenosis = the diameter of the artery at the site of the most severe stenosis and Dnormal = the diameter of the proximal normal artery. If the proximal segment was diseased, contingency sites were chosen to measure Dnormal: distal artery (second choice), feeding artery (third choice). Using a hand-held digital caliper, three neuroradiologists independently measured Dstenosis and Dnormal of 24 stenotic intracranial arteries. Each observer repeated the readings 4 weeks later. We determined how frequently two observers' measurements of percent stenosis of each of the 24 diseased arteries differed by 10% or less.RESULTS: Among the three pairs of observers, interobserver agreements were 88% (observer 1 versus observer 2), 79% (observer 1 versus observer 3), 75% (observer 2 versus observer 3) for the first reading and were 75% (observer 1 versus observer 2), 100% (observer 1 versus observer 3), and 71% (observer 2 versus observer 3) for the second reading. Intraobserver agreement for each of the observers was 88%, 83%, and 100%. Interclass correlation was 85% (first reading) and 87% (second reading). Intraclass correlation was 92% (first and second readings combined).CONCLUSION: This method shows good interobserver and intraobserver agreements for the measurement of intracranial stenosis of a major artery. If validated in subsequent studies, this method may serve as a standard for the measurement of percent stenosis of an intracranial artery.