Objective Evaluation of Cerebral Venous Sinus Attenuation on Plain CT Brain and Detecting Anemia. Noticing the "Unnoticed".

CONTEXT: Plain computed tomography (CT) of the brain is an important first-line investigation of choice in an acute neurologic setup. Unless clinically suspected concealed areas like the confluence of venous sinuses often go unnoticed. Diagnosing anemia, thrombosis, or polycythemia correlating the CT attenuation values might prove to be fruitful in early patient management where the mode of varied clinical presentations causes a clinical dilemma. AIMS: 1) To determine the objective correlation between CT attenuation of the cerebral venous sinus and hemoglobin (Hb) as well as hematocrit (HCT) value and 2) to detect anemia from measuring venous sinus attenuation. METHODS AND MATERIALS: An exploratory study design of 200 patients, who had plain CT of the head and Hb and HCT levels obtained within 24 h of the scan. STATISTICAL ANALYSIS USED: Two-tailed unpaired t-test was used to test the difference between two independent samples. Correlation and regression analyses were used to assess the correlation between two quantitative variables. RESULTS: A significant correlation was observed between the Hb-Hounsfield unit (HU) and HCT-HU. The simple linear regression model revealed that HU (P value < 0.001) was significantly correlated with Hb and the regression model was, Hb = 2.1 + 0.2 × HU. Similarly, HU (P value < 0.001) was significantly correlated with HCT and regression model was HCT = 6.2 + 0.7 × HU. CONCLUSIONS: Objective attenuation values of dural sinuses on plain CT can be positively correlated with Hb and HCT values. Considering the cutoff of 35.5 HU, we were able to show the specificity of 100% for the detection of anemia.

Plain CT vs MR venography in acute cerebral venous sinus thrombosis: Triumphant dark horse.

CONTEXT: Most patients with cerebral venous sinus thrombosis (CVST) present with nonspecific signs and symptoms and are likely to undergo nonenhanced head computed tomography (NCT) at presentation, which may show a normal report in up to two-thirds of patients. However, in case of acute thrombosis, sensitivity of diagnosing CVST is high as sinuses are hyperdense. Though magnetic resonance imaging (MRI) is considered the imaging modality of choice for diagnosing CVST, it is not universally available in an acute setting. AIMS: To evaluate whether increased attenuation in cerebral venous sinuses in acute condition can be used to diagnose acute CVST and to determine its diagnostic value. MATERIALS AND METHODS: The study involves two independent groups. One group of patients with sinus thrombosis were confirmed by MR venography (group A). The other group included patients without sinus thrombosis (group B). The HU (CT attenuation), hemoglobin (HGB), hematocrit (HCT), and H: H (HU: HCT) ratio of both groups were compared. Thirty-six patients (59 thrombotic sinuses) were studied in group A and 40 in group B. STATISTICAL ANALYSIS: Average HU and H: H ratio were compared using two-tailed t-test, and linear regression analysis was used to assess correlation between HCT and HU. RESULTS: Average HU (73.7 vs 48.6) and H: H ratio values were higher in group A patients compared to group B (P < 0.05). Linear regression analysis showed positive correlation between HGB and HCT with HU among both the groups (P < 0.05). CONCLUSIONS: Our study demonstrates that acute CVST can be diagnosed using HU values in NCT.