Περίληψη:
Background and Purpose - Intracranial arterial stenosis increases flow
velocities on the upslope of the Spencer’s curve of cerebral
hemodynamics. However, the velocity can decrease with long and severely
narrowed vessels. We assessed the frequency and accuracy for detection
of focal and diffuse intracranial stenoses using novel diagnostic
criteria that take into account increased resistance to flow with
widespread lesions.
Methods - We evaluated consecutive patients referred to a neurovascular
ultrasound laboratory with symptoms of cerebral ischemia. Transcranial
Doppler mean flow velocities were classified as normal (30 to 99 cm/s),
high and low. Pulsatility index >= 1.2 was considered high. Focal
intracranial disease was defined as >= 50% diameter reduction by the
Warfarin Aspirin in Symptomatic Intracranial Disease criteria. Diffuse
disease was defined as stenoses in multiple intracranial arteries,
multiple segments of one artery, or a long (> 1 cm) stenosis in one
major artery on contrast angiography (CT angiography or digital
subtraction angiography) as the gold standard.
Results - One hundred fifty-three patients (96 men, 76% white, age 62
+/- 15 years) had previous strokes (n=135) or transient ischemic attack
(n=18). Transcranial Doppler detection of focal and diffuse intracranial
disease had sensitivity 79.4% (95% CI: 65.8% to 93%), specificity
92.4% (95% CI: 87.7% to 97.2%), positive predictive value 75.0%
(95% CI: 60.9% to 89.2%), negative predictive value 94.0% (95% CI:
89.7% to 98.3%), and overall accuracy 89.5% (95% CI: 84.5% to
94.4%). After adjustment for stroke risk factors, transcranial Doppler
findings of low mean flow velocities and high pulsatility index in a
single vessel were independently associated with angiographically
demonstrated diffuse single vessel intracranial disease, whereas low
mean flow velocities/high pulsatility index in multiple vessels were
related to multivessel intracranial disease (OR: 19.7, 95% CI: 4.8 to
81.2, P < 0.001).
Conclusions - Diffuse intracranial disease may have a higher than
expected frequency in a select stroke population and can be detected
with noninvasive screening.
Συγγραφείς:
Sharma, Vijay K.
Tsivgoulis, Georgios
Lao, Annabelle Y. and
Malkoff, Marc D.
Alexandrov, Andrei V.
