Diagnostic ultrasound ( PDFDrive )

CHAPTER 47 Doppler Sonography of the Brain in Children 1599
Cerebrovascular Disease: Indicators in
Children With Sickle Cell Disease 66,67
Maximum velocity, OA ≥ 35 cm/sec
TAMM velocity, MCA ≥ 170 cm/sec
RI in OA ≤ 0.6
Velocity in OA greater than velocity in ipsilateral MCA
Maximum velocity in PCA, vertebral, or basilar arteries
greater than or equal to MCA velocity
Turbulence
Visualization of PCA or ACA without visualization of MCA
Any RI < 0.3
Maximum MCA PSV ≥ 200 cm/sec
A
ACA, Anterior cerebral artery; MCA, middle cerebral artery; OA,
ophthalmic artery; PCA, posterior cerebral artery; PSV, peak systolic
velocity; RI, resistive index, TAMM, time-averaged mean of the
maximum.
Data from Seibert JJ, Miller SF, Kirby RS, et al. Cerebrovascular
disease in symptomatic and asymptomatic patients with sickle cell
anemia: screening with duplex transcranial Doppler US—correlation
with MR imaging and MR angiography. Radiology. 1993;189(2):457-
466 66 ; Seibert JJ, Glasier CM, Kirby RS, et al. Transcranial Doppler,
MRA, and MRI as a screening examination for cerebrovascular
disease in patients with sickle cell anemia: an 8-year study. Pediatr
Radiol. 1998;28(3):138-142. 67
B
FIG. 47.5 Abnormal Ophthalmic Artery (OA) Flow in 16-Year-Old
Boy With Sickle Cell Disease. Patient had his irst left cerebrovascular
accident (CVA, stroke) at age 7 years. Spectral Doppler ultrasound
waveforms through the eye show increased diastolic low in both OAs.
(A) Increased velocity in the right OA with maximum velocity of 66 cm/
sec; (B) reversed low in the left OA.
Siegel et al. 68 compared transtemporal TCD to neurologic
examination and also found a maximum low in the MCA of
more than 200 cm/sec or less than 100 cm/sec (including no
low) as signiicant for disease. Verlhac et al. 63 studied SCD with
duplex Doppler imaging with a 3-MHz transducer transtemporally
and suboccipitally, as well as with MRA and MRI. Arteriography
was performed in patients with suspected stenosis on TCD
sonography. hey found that patients with a mean velocity greater
than 190 cm/sec had stenosis on arteriography. Kogutt et al. 69
evaluated symptomatic SCD patients and found 91% sensitivity
and 22% speciicity of TCD using MRA as the reference standard.
Abnormal TCD values were (1) maximum and mean velocity
(V max and V mean ) greater than 2 standard deviations (SD) from
normal values reported by Adams et al. 65,70 in SCD: V max MCA
> 168 ± −38 cm/sec and V mean MCA 115 ± −31 cm/sec, and V max
ACA 138 ± 34 cm/sec and V mean ACA 94 ± 28 cm/sec; (2) RI <
0.40; and (3) V max MCA < V max ACA (Fig. 47.12).
Screening sickle cell patients with the nonimaging pulsed
Doppler ultrasound technique involves scanning the patient
transtemporally to evaluate the MCA, bifurcation, DICA, ACA,
and PCA. he OA can be evaluated through the orbit. he basilar
and vertebral arteries can be evaluated from the occipital approach.
he PSV, EDV, TAMM velocity, and RI of each of these vessels
should be measured at least twice to obtain the most accurate
measurement. 71 he MCA should be tracked from the peripheral
branch to the bifurcation with velocities obtained every 2 mm.
Optimizing the tracing is crucial in identifying regions of stenosis.
72 Color Doppler low imaging (TCDI) can also be used
to screen SCD patients. his technique is faster to learn, allows
for quicker vessel identiication, and improves gate placement.
Because image-based probes tend to be larger than nonimaging
probes, however, optimizing the tracing may be more diicult
and can result in slightly lower velocities than those obtained
by nonimaging methods. 20,21
he Stroke Prevention Trial in Sickle Cell Anemia (STOP)
study led by Robert Adams showed that regular transfusion of
children at risk for stroke (based on Doppler sonography) could
prevent CVA. 19,72-75 Adams studied children age 2 to 16 years,
from 14 medical centers, who had MCA mean velocities higher
than 200 cm/sec and were at risk of developing stroke. Half
received blood transfusions every 3 to 4 weeks, enough to lower
sickle cell hemoglobin to below 30%. Ater 1 year, the transfusions
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