Intracranial atherosclerosis is responsible for 50,000 ischemic strokes each year in the USA. Noninvasive testing such as transcranial Doppler ultrasound (TCD) and magnetic resonance angiography (MRA) to identify intracranial atherosclerosis is in widespread use but has not been rigorously validated against the gold standard, catheter angiography. The recently NIH-funded WASID trial (Warfarin Aspirin Symptomatic Intracranial Disease) will compare warfarin with aspirin for stroke prevention in patients with intracranial atherosclerosis. WASID requires performance of angiography along with TCD and MRA, providing an opportunity to critically evaluate these nonivasive tests. Main Objective. The purpose of SONIA is to validate the noninvasive diagnosis of intracranial atherosclerosis. The primary aim of SONIA is to define velocity values on TCD and anatomic abnormalities on MRA that identify severe (50-99 percent) intracranial stenosis or large, proximal arteries seen on catheter angiography. SONIA will define the criteria, or cutpoints, for an abnormal TCD or MRA and show that they perform with a reliable positive predictive value (PPV). Study Design. SONIA will be conducted in collaboration with WASID. Study-wide cutpoints defining positive TCD and MRA have been developed and reviewed by the site investigators of WASID. Hard copy angiography, TCD and MRA generated in WASID will be centrally read in SONIA. The performance of TCD and MRA will be monitored and analyzed in SONIA to demonstrate cutpoints that achieve a PPV of 80 percent for the identification of severe intracranial stenosis on angiography. Conclusions. Central readings will be used to validate the cutpoints that function with a PPV of 80 percent and to develop measures of negative predictive value (NPV), inter- and intra-observer variability. Sensitivity and specificity will be determined after adjustment for verification bias and employed in receiver-operator characteristic analyses. SONIA will use these techniques to develop TCD or MRA cutpoints that minimize the clinical consequences of test errors that occur in the noninvasive evaluation of patients with suspected intracranial atherosclerosis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS039131-04
Application #
6540166
Study Section
Special Emphasis Panel (ZNS1-SRB-K (02))
Program Officer
Radziszewska, Barbara S
Project Start
1999-09-15
Project End
2004-06-30
Budget Start
2002-07-01
Budget End
2003-06-30
Support Year
4
Fiscal Year
2002
Total Cost
$519,160
Indirect Cost
Name
Rhode Island Hospital (Providence, RI)
Department
Type
DUNS #
161202122
City
Providence
State
RI
Country
United States
Zip Code
02903
Nahab, Fadi; Cotsonis, George; Lynn, Michael et al. (2008) Prevalence and prognosis of coexistent asymptomatic intracranial stenosis. Stroke 39:1039-41
Feldmann, E; Wilterdink, J L; Kosinski, A et al. (2007) The Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis (SONIA) trial. Neurology 68:2099-106
Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis (SONIA) Trail Investigators (2004) Stroke outcome and neuroimaging of intracranial atherosclerosis (SONIA): design of a prospective, multicenter trial of diagnostic tests. Neuroepidemiology 23:23-32