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(Stroke. 2007;38:1257.)
© 2007 American Heart Association, Inc.
Original Contributions |
From the Divisions of Neuroradiology (R.W., R.I.A., A.J.F., S.P.S.) and Neurology (D.J.S., D.J.G.) and the North and East GTA Regional Stroke Centre, Sunnybrook Health Sciences Centre, and the Department of Public Health Sciences (G.T.), University of Toronto, Toronto, Canada.
Correspondence to Dr R. Aviv, Diagnostic Imaging, Division of Neuroradiology, AG 31, Sunnybrook Health Sciences Centre, 2075 Bayview Ave, Toronto, M4N 3M5 Canada. E-mail richardaviv{at}lineone.net
| Abstract |
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Methods We prospectively studied 39 consecutive patients with spontaneous ICH by computed tomography angiography within 3 hours of symptom onset. Scans were reviewed by 3 readers. Patients were dichotomized according to the presence or absence of the spot sign. Clinical and radiological outcomes were compared between groups. The predictive value of this sign was assessed in a multivariate analysis.
Results Thirteen patients (33%) demonstrated 31 enhancing foci. Baseline clinical variables were similar in both groups. Hematoma expansion occurred in 11 patients (28%) on follow-up. Seventy-seven percent of patients with and 4% without hematoma expansion demonstrated the spot sign (P<0.0001). Sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio for expansion were 91%, 89%, 77%, 96%, and 8.5, respectively. Interobserver agreement was high (
=0.92 to 0.94). In patients with the spot sign, mean volume change was greater (P=0.008), extravasation more common (P=0.0005), and median hospital stay longer (P=0.04), and fewer patients achieved a good outcome (modified Rankin Scale score <2), although the latter was not significant (P=0.16). No differences in hydrocephalus (P=1.00), surgical intervention (P=1.00), or death (P=0.60) were noted between groups. In multiple regression, the spot sign independently predicted hematoma expansion (P=0.0003).
Conclusions The computed tomography angiography spot sign is associated with the presence and extent of hematoma progression. Fewer patients achieve a good clinical outcome and hospital stay was longer. Further studies are warranted to validate the ability of this sign to predict clinical outcomes.
Key Words: computed tomography angiography intracerebral hemorrhage prognosis stroke
| Introduction |
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Hematoma size has been shown to be one of the most important predictors of 30-day mortality.7 Hematoma expansion is highly predictive of neurological deterioration810 and is an independent predictor of mortality and functional outcomes.11 Accurate and reliable clinical and radiographic predictors of ICH growth are needed. With recombinant factor VIIa emerging as an investigational treatment for acute ICH, it will be particularly important to better predict which patients are most likely or least likely to benefit from such treatment.12,13 Although the incidence of serious adverse events has been shown to be low at <1%, factor VIIrelated thrombotic complications can occur,14 and it would be desirable to avoid treating patients in whom hematoma expansion is unlikely.
Computed tomography angiography (CTA) is a rapid, noninvasive investigation for patients with ICH and has proven useful for identifying potentially treatable entities such as aneurysms1520 and other vascular lesions.2123 In this report, we describe the CTA finding of tiny, enhancing foci, or the "spot sign," within hematomas, with or without clear contrast extravasation. We hypothesized that this sign is associated with hematoma expansion and poor clinical outcomes.
| Patients and Methods |
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| Materials/Image Acquisition |
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CT technologists perform all postprocessing, including multiplanar reformats at the CT operators console. Coronal and sagittal multiplanar reformat images are created as 10.0-mm-thick images, spaced by 3 mm. Bilateral rotational multiplanar reformat are created at each carotid terminus with a thickness of 7 mm and a spacing of 3 mm. All images were viewed on AGFA Impax 4.5 PACS workstations.
Imaging Analysis/Interpretation
All studies were prospectively evaluated by 3 neuroradiologists for the presence or absence of the CTA spot sign. This sign was defined as 1 or more 1- to 2-mm foci of enhancement within the hematoma on CTA source images (Figure 1B). Assessment is made by simple visual inspection and can easily be detected by nonradiologists. Spot location within the hematoma and the number of spots were noted. Extravasation was defined as enlargement of the contrast density on the immediately proceeding enhanced CT (Figure 1C). Hematoma location was classified as supratentorial or infratentorial. Supratentorial location was further subclassified as lobar or deep. Hematoma volumes were calculated on the initial and follow-up CTs at 1 to 2 days with the previously validated ABC/2 method.24 An increase of hematoma size >30% or >6 mL was considered significant enlargement.13,25
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Statistical Methods
The prevalence, number, and location of spots were recorded for each reviewer. The interobserver agreement for detection, number, and presence of extravasation was calculated with the multirater
statistic.26 Values of
of 0.21 to 0.4, 0.41 to 0.6, 0.61 to 0.8, and 0.81 to 1 were considered fair, moderate, substantial, and nearly perfect, respectively.27
Patients were classified according to the presence or absence of the spot sign. Baseline variables, including age, sex, antiplatelet/anticoagulant use, glucose levels, clotting profile, blood pressure, and hematoma size, were compared with Students t test and Fishers test for continuous and categorical data, respectively. Thresholds of glucose >8.3 mmol/L and mean arterial pressure (MAP) >120 mm Hg were selected on the basis of previous data.28
Diagnostic performance characteristics of the spot sign for clinically significant hematoma expansion were calculated. Absolute and percent ICH volume changes, presence of extravasation, hydrocephalus, surgical intervention, and 3-month modified Rankin Scale score were compared for the 2 groups. Univariate analyses and multivariable linear regression were used to assess the dependence of hematoma volume change on clinical and radiological factors. In addition to the spot sign, 3 important factors were identified a priori for the multiple-regression model: extravasation or use of anticoagulants; a history of hypertension or a measured MAP >120 mm Hg; and an elevated glucose value (>8.3 mmol/L). Three patients with outlying values for change in ICH volume were identified and were excluded from the multiple-regression results presented here. A multiple regression for all subjects according to robust methods29 gave essentially the same results. All data were analyzed with SPSS for Windows (version 14; SPSS, Inc, Chicago, Ill) and R, version 2.3.1.30 Confidence intervals for differences in proportions were computed with Newcombes method, and confidence intervals for differences in medians and for differences in percent changes in volume were computed with the bootstrap method. A value of P<0.05 was considered significant.
| Results |
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=0.85 to 0.94). Overall, the baseline characteristics (sex, initial hematoma size, systolic blood pressure, MAP >120 mm Hg, glucose level >8.3 mmol/L, international normalized ratio [INR], activated partial thromboplastin time [APTT], and history of anticoagulants) of the groups with and without the spot sign were similar. Follow-up study results (Table 1) demonstrated 11 patients (28%) with clinically important hematoma growth; 10 of these demonstrated foci of enhancement (91%) on the initial CTA. The diagnostic performance measures of spot sign for hematoma expansion are given in Table 2. We dichotomized the group with the spot sign according to the presence of extravasation. Six of these patients demonstrated contrast extravasation (46%), 4 were on warfarin, accounting for a higher INR (mean±SD, 2.0±1.1 vs 1±0.1; P=0.04) than those without extravasation. There was no significant difference in final volume or change of volume in the patients with extravasation (P=0.18). When patients with extravasation were excluded, the patients demonstrating the spot sign were still more likely to have a larger final hematoma size (P=0.001). Patients on anticoagulation were more likely to have multiple foci of enhancement (P=0.03), but there was no association between the INR/APTT level and number of spots. Patients with multiple spots had a similar initial hematoma volume (P=0.15) but a greater final absolute volume (P=0.01) than those with a single spot. Univariate analyses demonstrated the spot sign (P=0.0004), extravasation (P=0.00007), and anticoagulants (P=0.04) to be associated with hematoma growth, whereas a history of hypertension, MAP >120, and glucose >8.3 mmol/L had no significant association. In multiple regression, the spot sign (P=0.0003), extravasation (P=0.001), and anticoagulant history (P=0.02) were independently associated with an increase in volume, but again, a history of hypertension, high MAP, and high glucose were not (Table 2).
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Hematoma enlargement occurred significantly more frequently in patients with the spot sign than those without (P=0.0001). Mean absolute (P=0.008) and percentage (P=0.005) hematoma volume change, presence of extravasation (P=0.0005), and length of hospital stay (P=0.04) were greater when the spot sign was present. There was no statistically significant difference in the proportion of patients with surgical intervention or hydrocephalus between the 2 groups. Patients with the spot sign were less likely to achieve a good clinical outcome (Figure 2), although this did not reach statistical significance (P=0.15).
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| Discussion |
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Hematoma progression has been previously defined as an increase of between 33% and 50% or an absolute change in volume of between 12.5 and 20 mL.9,3133 However, studies evaluating hematoma growth in posttraumatic ICH have shown that an expansion of 5 mL predicted the need for late surgical evacuation.25 In addition, Mayer et al13 showed significantly worse outcomes in patients who did not receive factor VII, despite a difference in mean absolute increase of only 5.8 mL in the group treated with the highest dose. Accordingly, for the purposes of this study, a >30% or a >6-mL increase in volume was defined as hematoma expansion. Although the mechanisms of hematoma growth are not well understood, both primary and secondary vessel injury is proposed. A brief review is necessary to understand the possible etiology of these foci of enhancement, or spot sign.
Parenchymal microaneurysms and their rupture, initially described in 1868 by Charcot and Bouchard,38 have been implicated in the development of hypertensive ICH. The aneurysms are reported to measure up to 2 mm in size,39 well within the range of spatial resolution for CTA studies (0.5 mm). They occur in deep brain structures, including the basal ganglia and thalami, and are most commonly seen in elderly, hypertensive individuals.40,41 Early work described these lesions as being true aneurysms42; however, controversy has persisted regarding the true nature of these lesions.43 Possibilities suggested range from adherent clots or pseudoaneurysms,44 "bleeding globes,"45,46 and more recently, vascular tortuosity and coiling, artifactually producing the appearance of an aneurysm.47,48 Microaneurysm formation has also been implicated in the mechanism of hemorrhage in amyloid angiopathy49 and may be part of a common end pathway to hemorrhage in both hypertension and amyloid angiopathy.50 Secondary hemorrhage into perihematoma tissue is a further mechanism of hematoma expansion.51,52 Mechanical disruption and ischemia53 have been proposed, but increasingly, inflammatory mediators are implicated.5464 Bleeding from surrounding vessels may explain the tendency for irregular hematomas to expand.10 Whether expansion occurs more frequently from primary or secondarily damaged vasculature, both continued hypertension and coagulopathy are thought to contribute.3437
Despite numerous pathologic descriptions, including recent reports of actual ruptured microaneurysms within parenchymal hematomas,65,66 microaneurysms or evidence of vascular injury on conventional angiography or CTA are not well described. We demonstrated foci of contrast enhancement in 91% of expanded hematomas. Nearly half of the foci detected showed evidence of increased contrast puddling on the postcontrast CT performed immediately after CTA. The growth of contrast enhancement is presumed active extravasation. Anticoagulant administration and a higher mean INR in the extravasation group contributed to a larger hematoma size, but the spot sign remained an independent predictor of growth. Previous series showed that extravasation on CTA was predictive of hemorrhage enlargement from aneurysms and other vascular lesions.67 More recently, diffuse contrast extravasation has been reported as an independent predictor of in-hospital mortality28; however, CT examination was performed outside the window recommended for factor VII (median, 4.6 to 6 hours). Extravasation on magnetic resonance imaging has also been shown to indicate persistent hemorrhage and is correlated with hematoma enlargement.68 Active contrast extravasation on cerebral angiography associated with hematoma formation has been recognized since the 1970s.6972
It is unclear whether the foci of enhancement represent primary or secondary vessel injury. The peripheral location of enhancement supports the assertion that these foci represent active hemorrhage from secondarily damaged or torn perforators in the absence of an underlying aneurysm or aneurysm-like lesions. However, given the putative underlying mechanisms of ICH in both hypertension and amyloid angiopathy, it is reasonable to speculate that these spots may represent pseudoaneurysms, Charcot-Bouchard aneurysms, or amyloid-related microaneurysms.
Despite the demonstration that the spot sign is highly associated with hematoma expansion and the well-known association between expansion and increased morbidity and mortality, we were unable to detect a difference between the 2 groups. This may be attributable to the relatively small sample size. Similarly, only a small number of patients underwent surgical intervention or developed hydrocephalus. Finally, the indications for CTA in ICH are not well established, and as a result, not all patients with ICH underwent CTA. However, we believe the presented cohort to be representative of the population of patients presenting with spontaneous ICH.
In conclusion, we report the CTA spot sign, the presence of tiny, focal areas of contrast enhancement in association with ICH, which are independent and highly predictive of hematoma expansion. The sign is easily and reliably detected. The presence of this sign may be a useful radiological marker that should be validated in a larger prospective cohort.
| Acknowledgments |
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Dr David Gladstone is supported by the Heart and Stroke Foundation of Ontario. Dr Richard Aviv is supported by the Canadian Stroke Consortium.
Disclosures
None.
Received August 15, 2006; revision received October 19, 2006; accepted October 29, 2006.
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A. Ederies, A. Demchuk, T. Chia, D. J. Gladstone, D. Dowlatshahi, G. BenDavit, K. Wong, S. P. Symons, and R. I. Aviv Postcontrast CT Extravasation Is Associated With Hematoma Expansion in CTA Spot Negative Patients Stroke, May 1, 2009; 40(5): 1672 - 1676. [Abstract] [Full Text] [PDF] |
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L. H. Sansing, S. R. Messe, B. L. Cucchiara, S. N. Cohen, P. D. Lyden, S. E. Kasner, and For the CHANT Investigators Prior antiplatelet use does not affect hemorrhage growth or outcome after ICH Neurology, April 21, 2009; 72(16): 1397 - 1402. [Abstract] [Full Text] [PDF] |
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C. D. Barras, B. M. Tress, S. Christensen, L. MacGregor, M. Collins, P. M. Desmond, B. E. Skolnick, S. A. Mayer, J. P. Broderick, M. N. Diringer, et al. Density and Shape as CT Predictors of Intracerebral Hemorrhage Growth Stroke, April 1, 2009; 40(4): 1325 - 1331. [Abstract] [Full Text] [PDF] |
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J.J. Hopyan, D.J. Gladstone, G. Mallia, J. Schiff, A.J. Fox, S.P. Symons, B.H. Buck, S.E. Black, and R.I. Aviv Renal Safety of CT Angiography and Perfusion Imaging in the Emergency Evaluation of Acute Stroke AJNR Am. J. Neuroradiol., November 1, 2008; 29(10): 1826 - 1830. [Abstract] [Full Text] [PDF] |
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R.I. Aviv, D. Gladstone, J. Goldstein, M. Flaherty, J. Broderick, A. Demchuk, and for the Spot Sign for Predicting and Treating ICH Contrast Extravasation Predicts Hematoma Growth: Where to Now? AJNR Am. J. Neuroradiol., October 1, 2008; 29(9): e80 - e80. [Full Text] [PDF] |
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M. L. Flaherty, H. Tao, M. Haverbusch, P. Sekar, D. Kleindorfer, B. Kissela, P. Khatri, B. Stettler, O. Adeoye, C. J. Moomaw, et al. Warfarin use leads to larger intracerebral hematomas Neurology, September 30, 2008; 71(14): 1084 - 1089. [Abstract] [Full Text] [PDF] |
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C.-Y. Yang, Y.-F. Chen, C.-W. Lee, A. Huang, Y. Shen, C. Wei, and H.-M. Liu Multiphase CT Angiography versus Single-Phase CT Angiography: Comparison of Image Quality and Radiation Dose AJNR Am. J. Neuroradiol., August 1, 2008; 29(7): 1288 - 1295. [Abstract] [Full Text] [PDF] |
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S. A. Mayer, N. C. Brun, K. Begtrup, J. Broderick, S. Davis, M. N. Diringer, B. E. Skolnick, T. Steiner, and the FAST Trial Investigators Efficacy and Safety of Recombinant Activated Factor VII for Acute Intracerebral Hemorrhage N. Engl. J. Med., May 15, 2008; 358(20): 2127 - 2137. [Abstract] [Full Text] [PDF] |
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S. Gazzola, R. I. Aviv, D. J. Gladstone, G. Mallia, V. Li, A. J. Fox, and S. P. Symons Vascular and Nonvascular Mimics of the CT Angiography "Spot Sign" in Patients With Secondary Intracerebral Hemorrhage Stroke, April 1, 2008; 39(4): 1177 - 1183. [Abstract] [Full Text] [PDF] |
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S. A. Mayer and S. Schwab Advances in Critical Care and Emergency Medicine 2007 Stroke, February 1, 2008; 39(2): 261 - 263. [Full Text] [PDF] |
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