Table of Contents  
CASE REPORT
Year : 2013  |  Volume : 6  |  Issue : 3  |  Page : 308-309  

Abnormally hyperdense intracranial vessels on non-contrast computed tomography scan simulating dural venous sinus thrombosis in a case with high hematocrit


1 Department of Radiodiagnosis, Medical College and Hospital, Kolkata, West Bengal, India
2 Bankura Sammilani Medical College, Bankura, West Bengal, India
3 Bangur Institute of Neurosciences, Kolkata, West Bengal, India

Date of Web Publication5-Jul-2013

Correspondence Address:
Argha Chatterjee
46, Dr. Jagabandhu Lane, Kolkata - 700 012, West Bengal
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0975-2870.114663

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  Abstract 

Abnormal hyperdensity of intracranial blood vessels on non-contrast computed tomography scan (NCCT) may be found in cases with raised hematocrit. This finding not only simulates the appearance of a contrast enhanced CT scan but also may mimic dural venous sinus thrombosis. Here we report a case of child with Fallot's tetralogy and central cyanosis who showed abnormally hyperdense intracranial vessels on NCCT of head simulating the appearance of dural venous sinus thrombosis. The absence of suggestive clinical findings in the child, hyperdensity of intracranial arteries as well as the veins and a normal magnetic resonance venogram (MRV) suggested that the raised hematocrit is responsible for such appearance.

Keywords: Dural venous sinus thrombosis, hyperdensity, intracranial vessels, hematocrit, non-contrast computed tomography scan


How to cite this article:
Chatterjee A, Dhibar T, Dey D. Abnormally hyperdense intracranial vessels on non-contrast computed tomography scan simulating dural venous sinus thrombosis in a case with high hematocrit. Med J DY Patil Univ 2013;6:308-9

How to cite this URL:
Chatterjee A, Dhibar T, Dey D. Abnormally hyperdense intracranial vessels on non-contrast computed tomography scan simulating dural venous sinus thrombosis in a case with high hematocrit. Med J DY Patil Univ [serial online] 2013 [cited 2020 Dec 1];6:308-9. Available from: https://www.mjdrdypu.org/text.asp?2013/6/3/308/114663


  Introduction Top


Abnormal hyperdensity of intracranial blood vessels on non-contrast computed tomography (NCCT) scan may be found in patients with high hematocrit. This finding simulates the appearance of a contrast enhanced scan and mimics dural venous sinus thrombosis. Conditions that cause high hematocrit may also cause hypercoagulability which in turn predisposes to venous thrombosis. This suggests that a high hematocrit and dural venous sinus thrombosis may coexist. Therefore the knowledge of this NCCT appearance is important to achieve a correct diagnosis in such cases and to order further studies as and when necessary.


  Case Report Top


This three-year-old male child, a follow-up case of tubercular meningitis, was referred to the department of radio-diagnosis for a contrast enhanced CT (CECT) scan of head. The child completed anti-tubercular therapy and presently had no neurological symptoms. The child was also a known case of Fallot's tetralogy detected at about one and half year of age. The clinical examination of the child was significant for central cyanosis and finger clubbing [Figure 1]. The precordial evaluation and neurological examination were within normal limits. A review of hemogram reports showed hemoglobin of 18.5 g/dL (normal range: 11.5-13 g/dL) and hematocrit of 55.5% (normal range: 34-39%). The non-contrast CT scan revealed increased density of arteries at the Circle of Willis, deep cerebral veins and all visualized dural venous sinuses [Figure 2]. CT attenuation of the straight sinus was 62 Hounsfield units, which is abnormally high being in the range of a fresh clot. There was no other abnormality noted in the available images. Considering the possibility of dural venous sinus thrombosis a contrast examination was requested. However, the child did not cooperate for contrast injection. A magnetic resonance venogram (MRV) was done, which showed normal patency of large dural sinuses [Figure 3]. The absence of suggestive clinical features of dural venous sinus thrombosis and hyperdensity of intracranial arteries as well as the veins pointed towards the possibility that the hyperdensity of the venous sinuses is due to high hematocrit rather than venous sinus thrombosis. MRV confirmed this assumption.
Figure 1: Clinical photograph showing central cyanosis. Note also clubbing of fingers

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Figure 2: NCCT Head. (a) Section at the level of basal cisterns shows hyperdensity of arteries at the Circle of Willis. (b) Section at the level of thalamus shows hyperdensity of internal cerebral veins, vein of Galen (arrowhead) and sinus rectus

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Figure 3: MR venogram showing normal patency of dural venous sinuses

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  Discussion Top


CT attenuation of matter is dependent on its electron density, [1] and that of flowing blood is dependent on hemoglobin concentration. The globin component is predominantly responsible for the X-ray absorption by hemoglobin, the iron in heme contributing to less than 7%. [2] It is therefore likely that increased hemoglobin concentration of blood will cause increased attenuation of x-ray and consequent hyperdensity of blood vessels on CT scan. Polycythemia causing abnormal hyperdensity of intracranial blood vessels in CT scan of head is reported in literature albeit rarely. [3] New et al. [4] demonstrated a linear relationship between hematocrit and CT attenuation of whole blood, a finding corroborated by Ben Salem et al. [5] in patients with polycythemia. On the other hand, increased attenuation of dural venous sinuses is an early feature of dural venous sinus thrombosis as well. As venous sinus thrombosis is a known complication of conditions causing very high hematocrit (such as, polycythemia, severe dehydration), and both conditions may give rise to similar CT features, it is important to differentiate the two. The differentiation often requires magnetic resonance venography or catheter venography. [2] The absence of suggestive clinical features and hyperdensity of all cranial vessels including the arteries should suggest the possibility that hyperdensity of venous sinuses is due to raised hematocrit.


  Conclusion Top


Raised hematocrit may give rise to the unique finding of hyperdense intracranial vessels on CT scan and to the unwary may simulate the appearance of venous sinus thrombosis. Knowledge of this feature and further investigations, as necessary, will lead to correct diagnosis.

 
  References Top

1.Bushberg JT, Seibert JA, Leidholdt EM, Boone JM. The essential physics of medical imaging. 2 nd ed. Philadelphia: Lippincott Williams and Wilkins; 2002. p. 356.  Back to cited text no. 1
    
2.Healy JF, Nichols C. Polycythaemia mimicking venous sinus thrombosis. AJNR Am J Neuroradiol 2002;23:1402-3.  Back to cited text no. 2
    
3.Gayathri S, Prasad A, Sachdeva N, Baruah BP, Aggarwal S. Unique features of polycythemia observed on plain non-contrast CT scan of head. J Paediatr Neurosci 2010;5910:27-9.  Back to cited text no. 3
    
4.New PF, Aronow S. Attenuation measurements of whole blood and blood fractions in computed tomography. Radiology 1976;121:635-40.  Back to cited text no. 4
    
5.Ben Salem D, Osseby GV, Rezaizadeh-Bourdariat K, Pastural G, Martin D, Brunotte F, et al. Spontaneous hyperdense intracranial vessels seen on CT in polycythemia cases. J Radiol 2003;84:605-8.  Back to cited text no. 5
    


    Figures

  [Figure 1], [Figure 2], [Figure 3]


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