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.

Imaging Modality of Choice for Pre-Operative Cochlear Imaging: HRCT vs. MRI Temporal Bone.

INTRODUCTION: Congenital inner ear malformations occur as a result of the arrest or aberrance of inner ear development due to the heredity, gene mutation or other factors. Ever since the availability of cochlear implants, pre-operative evaluation by imaging of temporal bone has gained much attention. Precise selection of the candidate for cochlear implant dependent on preoperative radiological investigations. Only CT (Computed Tomography) and MRI (Magnetic Resonance Imaging) can provide a better picture of anatomy and pathology. AIM: To compare pre-operative imaging findings of both MRI and High Resolution Computed Tomography (HRCT) temporal bone and to find the best modality of choice in patients with bilateral profound Sensorineural Hearing Loss (SNHL). MATERIALS AND METHODS: This was a prospective, longitudinal, observational study conducted between June 2010 to November 2012. A total of 144 temporal bones were evaluated in 72 children with bilateral profound SNHL with congenital inner ear malformations. Each temporal bone was considered as a single case (144 cases). All the patients underwent HRCT and high field MRI study. MRI study included T2 W axial 3D FIESTA (Fast Imaging Employing Steady-state Acquisition) sequence. Anatomic abnormalities in each temporal bone were described and noted. For complete and better evaluation of Vestibulo-Cochlear Nerve (VCN) additional 3D oblique parasagittal view was taken perpendicular to the internal auditory canal with a small Field Of View (FOV). RESULTS: HRCT and MRI allowed accurate detection of inner ear malformations in children with bilateral SNHL. Majority of the patients presented with multiple structural abnormalities of inner ear. The common pathologies detected in the study were semicircular canal abnormality (89/144) followed by cochlear abnormalities (39/144). Most common cochlear abnormality was Mondini's deformity (14/144). MRI demonstrated absent of vestibulo-cochlear nerve in 15 cases. CONCLUSION: Few abnormalities of inner ear are better illustrated on CT, while others are better showed on MRI. Hence, neither HRCT nor MRI of the brain and temporal bones appears to be adequate imaging modality rather they are complementary to each other for pre-operative imaging of cochlear implantation.