Standardization of Flow Velocities with Respect to Age and Sex Improves the Accuracy of Transcranial Color Doppler Sonography of Middle Cerebral Artery Spasm
Jaroslaw Krejza1,2,
Zenon Mariak3 and
Janusz Lewko3
1 Department of Radiology, Bialystok Medical Academy, Sklodowskiej-Curie 24A,
15-279 Bialystok, Poland.
2 Present address: Department of Radiology, Division of Neuroradiology, Hospital
of the University of Pennsylvania, 3600 Market St., Science Bldg., Ste. 370,
Philadelphia, PA 19104.
3 Department of Neurosurgery, Bialystok Medical Academy, 15-279 Bialystok,
Poland.
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Fig. 1. —Histogram shows age distribution in group of patients
referred for cerebral angiography and transcranial color Doppler
sonography.
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Fig. 2A. —53-year-old man with moderate to severe spasm of right middle
cerebral artery. Anteroposterior angiogram shows narrowed segment of artery
(to 1.2 mm) adjacent to its proximal nonnarrowed part (3.4 mm).
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Fig. 2B. —53-year-old man with moderate to severe spasm of right middle
cerebral artery. Axial color Doppler sonogram shows right middle cerebral
artery (red) with sample volume placed on it. To determine angle of
insonation, we fitted direction of linear marker to be oriented along axis of
artery segment. Velocity waveforms are shown below image. Peak systolic
velocity in middle cerebral artery is increased to 264 cm/sec, well above
normal reference range.
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Fig. 3. —Graph shows receiver operating characteristic (ROC) curves
for standardized (solid line) and nonstandardized (dotted
line) peak systolic velocities for moderate to severe middle cerebral
artery narrowing spasm. Area of high sensitivity of ROC curve is above
dashed-and-dotted horizontal line at 0.75. Best efficiency (94%) was
associated with nonstandardized velocity threshold of 182 cm/sec and with
threshold of 170% of standardized peak systolic velocity.
Az (total area under ROC curve) = 0.934 for standardized,
0.923 for nonstandardized velocities. Azp (partial area
under ROC curve) = 0.214 for standardized, 0.204 for nonstandardized
velocities.
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Fig. 4. —Graph shows receiver operating characteristic (ROC) curves
for standardized (solid line) and nonstandardized (dotted
line) peak systolic velocities for all grades of middle cerebral artery
narrowing. Area of high sensitivity of ROC curve is above dashed-and-dotted
horizontal line at 0.75. Best efficiency was found with nonstandardized
velocity threshold of 160 cm/sec (efficiency, 86%) and with threshold of 170%
of standardized peak systolic velocity (efficiency, 89%).
Az (total area under ROC curve) = 0.858 for standardized,
0.827 for nonstandardized velocities. Azp (partial area
under ROC curve) = 0.131 for standardized, 0.118 for nonstandardized
velocities.
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Copyright © 2003 by the American Roentgen Ray Society.
