Acute Abdominal Venous Thromboses—The Hyperdense CT Sign:

Factors Contributing to Attenuation of Cerebral Venous Sinus in Brain Noncontrast Computed Tomography Scan

Background/Aim  In noncontrast computed tomography (NCCT), an apparently hyper-attenuated cerebral venous sinus (CVS) may lead to suspicion of CVS thrombosis. Understanding the factors affecting attenuation of CVS can guide us toward true diagnosis. Hence, the aim of the study was to determine the effect of different factors such as hematocrit, hemoglobin, age, blood urea nitrogen (BUN), creatinine, leukocyte and platelet count, and sex on the attenuation of CVS on brain NCCT.

Material and Methods  Total 1,680 patients were included in this study, and their demographic and laboratory data and brain NCCT were reviewed. In their brain NCCT, the average attenuation of superior sagittal sinus and both right and left sigmoid sinuses was measured. Data analysis was conducted using the Statistical Package for the Social Sciences version 21.0 software by Kolmogorov-Smirnov, Spearman's correlation coefficient, and multiple linear regression tests. The significance level was considered less than 0.05.

Results  Hematocrit (B = 0.251, p  < 0.001), hemoglobin (B = 0.533, p  < 0.001), and creatinine (B =  − 0.270, p  = 0.048) were determined as predictors of attenuation of superior sagittal sinus. For both sigmoid sinuses, hematocrit ( p  < 0.001) and hemoglobin ( p  < 0.001) were determined as positive predictors, and creatinine ( p  < 0.001) and BUN ( p  < 0.002) were determined as negative and positive predictors, respectively.

Conclusion  Hemoglobin, hematocrit, creatinine, and BUN are the main factors that should be considered in the assessment of CVS density on brain NCCT. As with increasing hematocrit and hemoglobin of the subject, the CVS density in NCCT increases, and with increasing creatinine and in some instance decreasing BUN of the subject, the CVS density in NCCT decreases.

Are cerebral veins hounsfield unit and H: H ratio calculating in unenhanced CT eligible to diagnosis of acute cerebral vein thrombosis?

Background:

For both the clinician and a radiologist, the diagnosis of cerebral venous sinus thrombosis (CVST), because of the variety of signs and symptoms, remains a challenge. In this study, the role of unenhanced brain computed tomography (CT) in the diagnosis of CVST was assessed.

Materials and Methods:

In this case–control study, unenhanced CT of 35 patients with acute CVST was compared with 70 normal patients. Hematocrit (HCT), creatinine, and blood urea nitrogen were recorded in all patients. CT images were read, and the attenuation was measured by two independent experienced radiologists. The H:H ratio was calculated for all patients in both case and control groups to normalized densities regarding HCT.

Results:

The mean of attenuation in patients was 66.95 ± 10.63 Hounsfield unit (HU) and in the controls was 52.51 ± 2.92 HU (P < 0.0001). The mean of H:H ratio in patients was 1.78 ± 0.40 and in controls was 1.46 ± 0.28 (P < 0.0001). Attenuation >60.4 HU was the best optimal cutoff with area under the curve of 0.918 (0.848–0.962) and had 71.4% sensitivity and 100% specificity. H:H ratio >1.42 as the optimal cutoff had 94.3% sensitivity and 54.3% specificity for identifying the CVST.

Conclusion:

Attenuation value >60.4 HU and H: H ratio >1.42 calculated based on unenhanced CT can be used as reliable methods to detect CVST in the absence of magnetic resonance imaging and magnetic resonance venography in the emergency setting.

Factors Affecting Attenuation of Dural Sinuses on Noncontrasted Computed Tomography Scan

BACKGROUND AND PURPOSE

Noncontrasted computed tomography (NCCT) is used as the initial neuroimaging test of choice for patients who present with new-onset neurological symptoms. An apparently hyperattenuated venous sinus may lead to the suspicion of cerebral venous sinus thrombosis (CVST). Improved understanding of all factors that can affect attenuation of dural sinuses can guide triage of patients to or from further investigations of suspected CVST. The purpose of this retrospective study was to assess the effect of different factors including hematocrit (HCT), hemoglobin (Hb), age, BUN/Cr ratio (blood urea nitrogen-to-creatinine ratio), and gender on the attenuation of dural sinuses on brain NCCT.

METHODS

A total of 1293 patients with neurological symptoms who presented to the emergency department were included in this study. For each patient, clinical assessment, laboratory investigations, and brain NCCT were reviewed. For each brain NCCT, the average attenuation of superior sagittal sinus and both right and left sigmoid sinuses was measured.

RESULTS

Positive significant correlations were found between average attenuation of dural sinuses on one hand and each of age, Hb, and HCT on the other hand. No significant correlation was found between average attenuation and BUN/Cr ratio. Gender discrepancy was also significant as higher attenuation was found in men.

CONCLUSION

Age, gender, and Hb levels are the main factors that should be taken into account upon the assessment of dural sinuses on brain NCCT. The highest normal attenuation is predicted in an elderly polycythemic man and the lowest is predicted in a young anemic woman.

Non-contrast computed tomography in the diagnosis of cerebral venous sinus thrombosis

BACKGROUND

The aim of the study was to investigate the sensitivity and specificity of non-contrast computed tomography (NCCT) in the diagnosis of cerebral venous sinus thrombosis (CVST). Methods. Screening our neurological department database, we identified 53 patients who were admitted to neurological emergency department with clinical signs of CVST. Two independent observers assessed the NCCT scans for the presence of CVST. CT venography and/or MR venography were used as a reference standard. Interobserver agreement between the two readers was assessed using Kappa statistic. Attenuation inside the cerebral venous sinuses was measured and compared between the patient and the control group.

RESULTS

CVST was confirmed in 13 patients. Sensitivity and specificity of NCCT for overall presence of CVST were 100% and 83%, respectively, with Kappa value of 0.72 (a good agreement between observers). The attenuation values between CVST patients and control group were significantly different (73.4 ± 14.12 HU vs. 58.1 ± 7.58 HU; p = 0.000). The ROC analysis showed an area under the curve (AUC) of 0.916 (95% CI, 0.827 - 1.00) and an optimal cutoff value of 64 HU, leading to a sensitivity of 85% and specificity of 87%.

CONCLUSIONS

NCCT as a first-line investigation has a high value for diagnosis of CVST in the emergency setting. The additional measurement of the sinus attenuation may improve the diagnostic value of the examination.

CT density measurement and H:H ratio are useful in diagnosing acute cerebral venous sinus thrombosis

BACKGROUND AND PURPOSE

Brain CT is widely used to exclude or confirm acute cerebral venous sinus thrombosis. The purpose of this study was to assess the value of attenuation measurement and the H:H ratio on unenhanced brain CT scans in the diagnosis of acute cerebral venous sinus thrombosis.

MATERIALS AND METHODS

This retrospective study evaluated 20 patients with acute cerebral venous sinus thrombosis and 20 age- and sex-matched control participants without thrombosis. Three experienced observers independently evaluated the unenhanced brain CT scan for the presence of cerebral venous sinus thrombosis and measured the attenuation in the dural sinuses. Interreader differences were examined, as well as densities and H:H ratio between patients with acute cerebral venous sinus thrombosis and control participants.

RESULTS

A significant difference in the average sinus attenuation was found between patients with acute cerebral venous sinus thrombosis (73.9 ± 9.2 HU) and the control group (52.8 ± 6.7 HU; P < .0001). A similar difference was found for the H:H ratio (1.91 ± 0.32 vs 1.33 ± 0.12 in patients with and without cerebral venous sinus thrombosis, respectively; P < .0001). Optimal thresholds of 62 HU and 1.52 lead to accuracies of 95% for average sinus attenuation and 97.5% for the H:H ratio, respectively.

CONCLUSIONS

Hyperattenuation and the H:H ratio in the dural sinuses on unenhanced brain CT scans have a high accuracy in the detection of acute cerebral venous sinus thrombosis.