Original ArticleCorrelation Between Contrast Time–Density Time on Digital Subtraction Angiography and Flow: An in Vitro Study
Introduction
Quantification of cerebral blood flow is of considerable importance in the evaluation and management of cerebrovascular disease, and quantification of blood flow in individual vessels flow provides a better understanding of its hemodynamic effects. Quantitative magnetic resonance angiography (QMRA) accuracy in measuring single-vessel flow has been widely validated with in vitro and in vivo experiments.1, 2, 3, 4, 5, 6, 7, 8, 9, 10 Digital subtraction angiography (DSA), with its excellent spatial and time resolution, has the additional benefit of its availability in the operating room during endovascular intervention. Multiple techniques have been proposed to extrapolate blood flow information from DSA runs, using contrast material bolus travel along the vessel as tracking method or mass conservation law as computational method. Among the tracking algorithms, several parametric color codes11, 12, 13, 14 and time–density curves15, 16, 17, 18, 19, 20, 21 have been developed from postprocessing analysis of contrast material intensity change over time and have been validated in vivo. Our group recently validated the correlation between contrast material transit time on DSA with cerebral arteriovenous malformation flow measured by QMRA.22 Even though several studies have investigated the accuracy of time density methods against in vitro flow measurements,23, 24, 25 many of these methods, when applied in real clinical settings, were unable to acquire quantitative measurements simultaneously in all vessels captured in the imaging procedure, and flow measurements were often obtained only in a single vessel of the entire vascular tree. Our method, by contrast, is able to acquire flow measurements simultaneously in all contrast material–enhanced areas included in the x-ray field. Here, we investigated the accuracy of contrast time–density time (TDT) on DSA against known flow values in a controlled laboratory setting.
Section snippets
Flow Model
A single U-shaped tube model, 500 mm long and with a constant inner diameter of 3 mm, connected with a programmable flow pump (CompuFlow 1000MR, Shelly Medical Imaging Technology, Ontario, Canada), was constructed to simulate a steady-state flow (Figure 1). The flow model was filled with commercially available blood mimicking fluid (40/60 glycerol/distilled water mixture by volume, density of 1.1 g/mL and viscosity of 3.5 cP), and flow values ranged from 30 to 240 mL/min.
A power contrast medium
All DSA Projections
TDI10%-100% correlated significantly with flow (P < 0.001, r = 0.88) (Figure 3A).
A good correlation was also noted for TDI100%-10% (P < 0.001, r = 0.65) (Figure 3B); 2 data points were excluded because they were above 2 standard deviations of mean TDI100%-10%. Faster flow was also associated significantly with higher TDI25%-25% (P < 0.001, r = 0.85) (Figure 3C). All results are shown in Table 1.
Anterior–Posterior DSA Projections
Considering only the anterior–posterior DSA projections in the statistical analysis, we found a
Discussion
The DSA technique provides excellent spatial and temporal resolution, and it is possible to extrapolate flow parameters through a rapid acquisition of the quantitative data it provides. Few postprocessing software programs are currently available to quantify vessel blood flow indirectly by contrast material time–density curve analysis11, 12, 13, 14 (syngo iFlow, Siemens Healthineers, Malvern, Pennsylvania, USA; Allura Xper, Philips Healthcare, Andover, Massachusetts, USA; AngioViz, GE
Conclusions
A significant correlation of TDI with controlled laminar flow was shown. Although this was an experimental situation, the method used may serve as an indirect technique to reliably extrapolate cerebral blood flow measurements from standard DSA data in real time in the neuroangiography suite.
References (32)
- et al.
Improved phase-contrast flow quantification by three-dimensional vessel localization
Magn Reson Imaging
(2000) - et al.
Application of color-coded digital subtraction angiography in treatment of indirect carotid-cavernous fistulas: initial experience
J Chin Med Assoc
(2013) - et al.
Angiographic assessment of cerebral circulation time for outcome prediction in patients with subarachnoid hemorrhage
Surg Neurol
(2004) - et al.
Parametric digital subtraction angiography imaging for the objective grading of collateral flow in acute middle cerebral artery occlusion
World Neurosurg
(2016) - et al.
Regional cerebral blood flow using quantitative MR angiography
AJNR Am J Neuroradiol
(2007) - et al.
Use of quantitative magnetic resonance angiography to stratify stroke risk in symptomatic vertebrobasilar disease
Stroke
(2005) - et al.
Quantitative magnetic resonance angiography in the evaluation of the subclavian steal syndrome: report of 5 patients
J Neuroimaging
(2009) - et al.
The utility of quantitative magnetic resonance angiography in the assessment of intracranial in-stent stenosis
Stroke
(2009) Wingspan stenting of symptomatic extracranial vertebral artery stenosis and perioperative evaluation using quantitative magnetic resonance angiography: report of two cases
Neurosurg Focus
(2008)- et al.
Leptomeningeal collateral volume flow assessed by quantitative magnetic resonance angiography in large-vessel cerebrovascular disease
J Neuroimaging
(2009)
Transarterial embolization of vein of Galen malformations: the use of magnetic resonance imaging noninvasive optimal vessel analysis to quantify shunt reduction: report of two cases
J Neurosurg
Clinical utility of quantitative magnetic resonance angiography in the assessment of the underlying pathophysiology in a variety of cerebrovascular disorders
Eur J Radiol
In vivo evaluation of quantitative MR angiography in a canine carotid artery stenosis model
AJNR AM J Neuroradiol
Monitoring peri-therapeutic cerebral circulation time: a feasibility study using color-coded quantitative DSA in patients with steno-occlusive arterial disease
AJNR Am J Neuroradiol
Angiographic perfusion imaging: real time assessment of endovascular treatment for cerebral vasospasm
J Neuroimaging
Color intensity projection of digitally subtracted angiography for the visualization of brain arteriovenous malformations
Neurosurgery
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Conflict of interest statement: Dr. Alarah is a recipient of grants from the National Institutes of Health and is a consultant for Cordis-Codman. Dr. Charbel has a ownership interest in VasSol Inc. and is a consultant for Transonic.