Gonzalez NR, Boscardin WJ, Glenn T, Vinuela F, Martin NAVasospasm probability index: a combination of transcranial Doppler velocities, cerebral blood flow, and clinical risk factors to predict cerebral vasospasm after aneurysmal subarachnoid hemorrhage. J Neurosurg 107:1101-1112

Division of Neurosurgery, David Geffen School of Medicine, University of California at Los Angeles, California 90025-7039, USA.
Journal of Neurosurgery (Impact Factor: 3.74). 01/2008; 107(6):1101-12. DOI: 10.3171/JNS-07/12/1101
Source: PubMed


The goal in this study was to create an index (vasospasm probability index [VPI]) to improve diagnostic accuracy for vasospasm after subarachnoid hemorrhage (SAH).
Seven hundred ninety-five patients in whom aneurysmal SAH was demonstrated by computed tomography, and in whom one or more intracranial aneurysms had been diagnosed, underwent transcranial Doppler (TCD) studies between April 1998 and January 2000. In 154 patients angiography was performed within 24 hours of the TCD examination, and in 75 133Xe cerebral blood flow (CBF) studies were obtained the same day. Seven cases were excluded because of a limited sonographic window. Forty-one women (60.3%) and 27 men (39.7%) between the ages of 35 and 84 years (58.0 +/- 13.2 years [mean +/- standard deviation]) were included. Clinical characteristics analyzed included age, sex, Hunt and Hess grade, Fisher grade, days after SAH, day of treatment, type of treatment (coil embolization, surgical clip occlusion, or conservative treatment), smoking history, and hypertension history. Lindegaard ratios and spasm indexes (TCD velocities/hemispheric CBF) were calculated bilaterally. Digital subtraction angiography images were measured at specific points of interest. Sensitivity, specificity, predictive values, and global accuracy of the different tests were calculated. Logistic regression was used to evaluate the possible predictive factors, and the coefficients of the logistic regression were integrated to create the VPI.
In 18 patients (26.5%) symptomatic vasospasm was diagnosed, and 33 (48.5%) had angiographic evidence of vasospasm. For TCD velocities above 120 cm/second at the middle cerebral artery, the global accuracy was 81.1% for the diagnosis of clinical vasospasm and 77.2% for angiographic vasospasm. For a Lindegaard ratio higher than 3.0, the accuracy was 85% for clinical vasospasm and 83.2% for angiographic vasospasm. A spasm index higher than 3.5 had an accuracy of 82.0% for the diagnosis of clinical vasospasm and 81.6% for angiographic vasospasm. The selected model for estimation of clinical vasospasm included Fisher grade, Hunt and Hess grade, and spasm index. The VPI had a global accuracy of 92.9% for clinical vasospasm detection. For diagnosis of angiographic vasospasm, the model included Fisher grade, Hunt and Hess grade, and Lindegaard ratio. The VPI achieved a global accuracy of 89.9% for angiographic vasospasm detection.
The use of TCD velocities, Lindegaard ratio, and spasm index independently is of limited value for the diagnosis of clinical and angiographic vasospasm. The combination of predictive factors associated with the development of vasospasm in the new index reported here has a significantly superior accuracy compared with the independent tests and may become a valuable tool for the clinician to evaluate the individual probability of cerebral vasospasm after aneurysmal SAH.

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    • "We used advanced MRI-based ASL procedures that quantify regional CBF values with greater sensitivity and specificity than Doppler procedures [32]. Typically, Doppler procedures can provide 85% accuracy [14], while ASL techniques can provide up to 100% [4], relative to invasive radioactive tracer procedures. Also, Doppler procedures are operator-dependent, allow limited evaluation of only some brain vessels, e.g., middle cerebral arteries, are relatively low-resolution, and are very time-consuming over ASL techniques. "
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    ABSTRACT: Obstructive sleep apnea (OSA) is a condition characterized by upper airway muscle atonia with continued diaphragmatic efforts, resulting in repeated airway obstructions, periods of intermittent hypoxia, large thoracic pressure changes, and substantial shifts in arterial pressure with breathing cessation and resumption. The hypoxic exposure and hemodynamic changes likely induce the structural and functional deficits found in multiple brain areas, as shown by magnetic resonance imaging (MRI) procedures. Altered cerebral blood flow (CBF) may contribute to these localized deficits; thus, we examined regional CBF, using arterial spin labeling procedures, in 11 OSA (age, 49.1±12.2 years; 7 male) and 16 control subjects (42.3±10.2 years; 6 male) with a 3.0-Tesla MRI scanner. CBF maps were calculated, normalized to a common space, and regional CBF values across the brain quantified. Lowered CBF values emerged near multiple bilateral brain sites in OSA, including the corticospinal tracts, superior cerebellar peduncles, and pontocerebellar fibers. Lateralized, decreased CBF appeared near the left inferior cerebellar peduncles, left tapetum, left dorsal fornix/stria terminalis, right medial lemniscus, right red nucleus, right midbrain, and midline pons. Regional CBF values in OSA are significantly reduced in major sensory and motor fiber systems and motor regulatory sites, especially in structures mediating motor coordination; those reductions are often lateralized. The asymmetric CBF declines in motor regulatory areas may contribute to loss of coordination between upper airway and diaphragmatic musculature, and lead to further damage in the syndrome.
    Neuroscience Letters 09/2013; 555. DOI:10.1016/j.neulet.2013.09.033 · 2.03 Impact Factor
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    • "Despite these shortcomings, clinicians have combined several different TCD-derived calculations to improve diagnostic sensitivity. Gonzalez et al. [13] combined the Lindegaard ratio (middle cerebral artery flow velocity/internal carotid artery flow velocity) and spasm index (TCD velocity/hemispheric cerebral blood flow (CBF)) in a retrospective mathematical model, which increased the sensitivity to 85%, compared to 69–76% for measurements analyzed in isolation. A separate study found that the sensitivity could be increased to 77% by using the ratio of ipsilateral to contralateral MCA mean blood flow volume (mBFV) [14]. "
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    ABSTRACT: Subarachnoid hemorrhage related to aneurysmal rupture (aSAH) carries significant morbidity and mortality, and its treatment is focused on preventing secondary injury. The most common-and devastating-complication is delayed cerebral ischemia resulting from vasospasm. In this paper, the authors review the various surveillance technologies available to detect cerebral vasospasm in the days following aSAH. First, evidence related to the most common modalities, including transcranial doppler ultrasonography and computed tomography, are reviewed. Continuous electroencephalography and older instruments such as positron emission tomography, xenon-enhanced CT, and single-photon emission computed tomography are also discussed. Invasive strategies including brain tissue oxygen monitoring, microdialysis, thermal diffusion, and jugular bulb oximetry are examined. Lastly, near-infrared spectroscopy, a recent addition to the field, is briefly reviewed. Each surveillance tool carries its own set of advantages and limitations, and the concomitant use of multiple modalities serves to improve diagnostic sensitivity and specificity.
    Neurology Research International 06/2013; 2013:256713. DOI:10.1155/2013/256713
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    • "This can be accomplished by measuring velocities in the cervical internal carotid artery (ICA) in addition to the intracerebral vessels and creating ratios for clinical use. TCD velocities have been used to create several clinically relevant predictive indices including the Lindegaard Ratio (ratio of MCA TCD velocity to ipsilateral ICA TCD velocity) [11], the Jakobsen Spasm Index (ratio of TCD velocity to CBF via 133Xe) [12], the Vasospasm Probability Index (VPI) [13], and the Ipsilateral/Contralateral MCA mBFV. The Lindegaard Ratio is especially useful for vasospasm diagnosis. "
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    ABSTRACT: The pathophysiology of cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH) is complex and is not entirely understood. Mechanistic insights have been gained through advances in the capabilities of diagnostic imaging. Core techniques have focused on the assessment of vessel caliber, tissue metabolism, and/or regional perfusion parameters. Advances in imaging have provided clinicians with a multifaceted approach to assist in the detection of cerebral vasospasm and the diagnosis of delayed ischemic neurologic deficits (DIND). However, a single test or algorithm with broad efficacy remains elusive. This paper examines both anatomical and physiological imaging modalities applicable to post-SAH vasospasm and offers a historical background. We consider cerebral blood flow velocities measured by Transcranial Doppler Ultrasonography (TCD). Structural imaging techniques, including catheter-based Digital Subtraction Angiography (DSA), CT Angiography (CTA), and MR Angiography (MRA), are reviewed. We examine physiologic assessment by PET, HMPAO SPECT, Xe Clearance, Xenon-Enhanced CT (Xe/CT), Perfusion CT (PCT), and Diffusion-Weighted/MR Perfusion Imaging. Comparative advantages and limitations are discussed.
    Neurology Research International 02/2013; 2013(6):415960. DOI:10.1155/2013/415960
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