European Journal of Cardiovascular Medicine

CVT is a kind of cerebrovascular illness characterized by localized cerebral oedema, venous cerebral infarction, seizures, and intracranial hypertension.^1,2 The condition primarily affects young people, women of reproductive age, and children. Previously, the incidence was estimated to be 0.2-0.5 per 100,000 person-years.^1,3 However, more recent investigations have found that the incidence of CVT is higher than expected, maybe as high as 1.32-1.57 per 100,000 person-years.

Cerebral venous thrombosis is a difficult condition to diagnose. The vast range of clinical symptoms of this uncommon illness contributes significantly to the diagnostic challenge.⁶ CVT can occur at any age, from infancy to old age, with the majority of recorded cases occurring in women during puerperium.⁷ Cerebral vein thrombosis is uncommon in comparison to arterial stroke and frequently affects young people.⁸ Cerebral venous infarctions is the most devastating result of cerebral venous thrombosis. Venous infarctions are frequently multifocal and bilateral, affecting both grey matter and subcortical white matter.

The mechanism of onset varies greatly, ranging from acute to gradual, therefore cerebral venous thrombosis can mimic a variety of conditions.⁹ Given these diverse clinical presentations, unenhanced computed tomography (CT) is typically the first test performed. Unenhanced CT may reveal nonspecific alterations and a spontaneously hyperattenuating thrombus. CT venography has proven to be a reliable tool for investigating the structure of cerebral veins, with a reported sensitivity of 95% with multiplanar reformatted (MPR) images when compared to digital subtraction angiography (DSA) as the reference standard.¹⁰

Because of the increased morbidity and mortality associated with cerebral vein thrombosis, it is critical to accurately detect less clinically severe cases of CVT to alter the "natural history" of this illness. Though the data on cerebral vein thrombosis from this region of the country is not limited, the vast range of presentations necessitates further research into this area.

This study was carried out in a teaching hospital with a medical college, attracting a representative sample from all areas, particularly the poorer strata of society. The findings of this study are thus applicable to the broader public in this region of the country. By investigating the varied radiologic manifestations, this study hopes to raise awareness about the condition so that effective measures can be used to combat it.

To study the varied findings of CVT on CT Venography in clinically suspected cases.

Study Design: A prospective hospital-based observational study.

Study area: Department of Radio Diagnosis, in a tertiary care teaching hospital.  

Study Period: 1 year.

Study population: Patients with signs and symptoms of cerebral venous thrombosis were referred for CT Venography to the Department of Radio Diagnosis. 

Sample size: The study consisted of 50 subjects.

Sampling method: Simple random technique.

Inclusion criteria:

1. All Patients diagnosed by the imaging studies.
2. Any age group presenting with Cerebral venous thrombosis.
3. Puerperal and non-puerperal group.

Exclusion criteria:

1. Patients with contrast allergy.
2. Patients with serum creatinine>1.5.

Ethical consideration: Institutional Ethical committee permission was taken prior to the commencement of the study.

Study tools and Data collection procedure:

CT venography can be defined as a fast thin-section volumetric helical CT examination performed with a time-optimized bolus of contrast medium to enhance the cerebral venous system. The examination includes the region from the calvarial vertex down to the first vertebral body to visualise the intracranial veins and sinuses. We include the atlas (C1) in the study to ensure incorporation of the origin of the jugular internal veins.

SCAN PROTOCOL:

1. Machine: Bright Speed scanner (GE Healthcare, Milwaukee, Wis) having a 16-row detector ring.
2. Section thickness: 0.625mm
3. Pitch: 0.9
4. Contrast: Non-ionic medium Dose: 1ml/kg body weight Scan delay: 45sec

Rate       : 3ml/sec

5. Coverage: C1 to vertex

Statistical analysis:

Data will be analysed using SPSS 21.0 software. Descriptive parameters will be represented as mean with SD or median. Continuous variables will be compared using unpaired t-test/Mann Whitney u test. Chi-square or t-test will be used to determine significant outcome differences. Categorical data will be represented as frequency with percentage. For all tests, a p-value of <0.05 will be considered statistically significant.

Table No. 1: Patients affected by age group

The majority of patients were in the third decade of their age (33).12 patients were in above fourth decade of their age .4 pts were <18 years of age. The mean age was 32.18 with a standard deviation of 13.14 a maximum age of 76, and a minimum age of 2 years.

In the present study of a total of 50 patients, there were 27 female and 23 male patients.

The majority of patients (35) had a duration of symptoms less than 30 days (subacute presentation). A small no. of patients (8) had symptom duration less than 24 hrs (acute presentation) and 7 had symptoms present more than a month (chronic presentation).

Table No. 2: Distribution of patients according to the sensorium

Most patients (43) were in normal sensorium while 7 were drowsy. Glasgow Coma Scale (GCS) was available in all patients. 3 of the patients had a GCS of less than 10.

In a total of 50 patients 31 had headache as a symptom at the time of presentation.

Table No. 3: Seizures type

In a total of 50 patients, 29 patients had a complaint of seizures (most common being the partial type of seizures) whereas the rest 21 patients had no such complaint.

On ophthalmic examination by slit lamp and direct ophthalmoscopy out of 50 patients 27 were having papilledema at the time of admission.

Table No. 4: Affected Region

Non-contrast CT Findings

Infarction was present in 36 (72%)of them out of which 27 had haemorrhagic infarction. 9 patients had non-haemorrhagic infarction. According to the site, 45 patients had cortical infarction while 5 had deep infarction. I patient had evidence of both cortical and deep infarctions. Other than infarction, abnormalities noted on the CT scan were mass effect & diffuse oedema in 2 pts 5 pts had cord sign 4 had empty delta sign.

Table No. 5: Mode of onset, clinical presentation and outcome according to the site of venous occlusion

Involvement of the sinuses based on CT venography:

Superior sagittal sinus (the commonest sinus involved) was involved in 39 patients, (isolated SSS in 7 pts). Total involvement was seen in 11 patients while in other patients anterior, middle and posterior parts involved with various combinations of other sinuses

Transverse sinus was the next most common sinus involved at 33 pts, (isolated in 4 pts) followed by sigmoid sinus at 22 pts. The superficial venous system was involved in 5 pts (isolated in 2 pts) while the deep venous system was involved in 5 pts. The majority (39 pts) of patients had a combination of sinus and vein involvement, and 11 pts had only isolated sinus involvement.

Correlation between the site of venous occlusion and clinical parameter:

Correlation with etiology showed no constant pattern except that isolated lateral sinus was involved in Mastoiditis. Correlation with mode of onset showed no difference in onset whether sinuses alone vs deep venous vs combination of sinuses and veins involved. No significant difference between the presence of thrombus in various sinuses and veins and the location of infarction. When cortical veins are involved patients were presented with seizures and have intracranial hematoma than when only sinuses were involved.

Fig. No. 1: Axial unenhanced CT images with a “dense triangle” sign (arrowhead) and a cord sign(arrow), findings suggestive of sinus and cortical vein thrombosis.

Fig No.2: Axial unenhanced CT images with increased attenuation in the left transverse sinus (cord sign) *

Fig. No.3: Axial unenhanced CT image shows an area of low attenuation in both thalami (*) associated with increased attenuation in the straight sinus (arrow) and internal cerebral veins (arrowheads).

Fig No. 4: Three-dimensional integral image from CT venography shows filling defects in the left transverse sinus and temporo-occipital veins, an appearance consistent with thrombosis.

Fig No. 5: Axial unenhanced CT image shows low attenuation in the left sigmoid sinus (arrow) and jugular foramen (arrowhead)

Fig No. 6: Unenhanced CT image showing thrombosis as hyperdensity (dense clot sign).

Cerebral venous thrombosis is characterised by intracranial veins and sinuses thrombosis, resulting in parenchymal damage and a rise in intracranial pressure. The radiological hallmark of this condition is thrombosis of intracranial sinuses and veins with or without haemorrhagic infarction and edema with or without evidence of herniation. In this study, a total of 50 patients with Radiological features of cerebral venous thrombosis were evaluated throughout 2 years. 23 out of 50 patients were male and the remaining 27 were female. This study of 50 patients with CVT cannot give precise information about the real incidence of the disease. cannot make any generalization of the results to the whole country. It has been suggested that the incidence of CVT was higher in females and in the aged, this was not confirmed in the present series, in which Male to Female ratio is 23: 27. As this data is not consistent with previous Indian studies viz. Bansal et al.¹¹, Srinivasan et al.¹² Nagaraja et al⁷. High proportion of postpartum CVT patients was also observed by Cantu et al.¹³, from Mexico with similar socio-demographic characteristics and economic status of the patients as in India. Due to referral bias, these findings of the high proportion of CVT cases were not replicated in some other studies viz. Deschiens et al.¹⁴  and Daif et al¹⁵. The possible explanation may be that the etiological factors, as well as clinical profile of CVT, are in this part of the state compared to other parts of India. More than half of the patients of CVT evaluated were in the third decade of their age (33 out of 50). The mean age of the patients was 32.18 years similar to earlier studies from India (Nagaraja et al²) Like all other series, the present one represents a selected group of patients not representative of the numerous causes that have been described. However, it confirms the fact that the frequency of septic CVT (6 out of 50) has markedly declined with the advent of antibiotics. It also confirms the role of oral contraceptives48 found as the only aetiologic factor in 3 of our patients. This has now led us, as many others to stop oral contraceptives and promptly look for CVT in women presenting with any of the neurological manifestations described in this study, particularly persistent headache, focal deficits or seizures.

In the present study in addition to conventional risk factors Dehydration (8%) and OCP use (10%) are significant risk factors, 8% of patients have Anemia, whether this is a reflection of the high incidence of anaemia in the Indian population particularly in the pregnant females or anaemia is a real risk factor needs further evaluation. In 10 out of 50 cases, no cause could be found, however complete etiological workup could not be completed. Headache (31 out of 50) with or without vomiting, seizures (29 out of 50). Altered sensorium (7 out of 50) and Focal deficits (23 out of 50) Papilledema, present in 54% of our cases, (was slightly more frequent than in other series) were the major clinical features noted at the presentation. The clinical presentation could be summarized in 3 main patterns, each of them simulating another neurological disease. The most frequent and homogeneous one was the progressive onset of signs of intracranial hypertension corresponding to the "Benign intracranial hypertension" or "pseudo-tumour cerebri" syndromes, confirming sinus thrombosis in 27 out of 50 cases.  These syndromes should be diagnosed purely on clinical, CSF and CT scan findings to rule out the possibility of sinus thrombosis. Some had (8 out of 23) the sudden onset of focal deficits simulating arterial strokes but with more frequent seizures (21 out of 29). The third presentation simulated an abscess (5 out of 50) with deficits and/or seizures with or without intracranial hypertension evolving over a few days to a month. Other less common presentations are headaches of sudden onset simulating subarachnoid hemorrhage (1 patient) It is therefore clear that CVT has no single clinical presentation and this is why it is necessary to systematically contemplate this diagnosis in order not to overlook it. Present series most of the patients had good outcomes. An earlier study by Nagaraja et al² grouped clinical features of CVT into four categories depending upon the topographical venous involvement.

The present series confirms the fact that isolated single sinus involvement was less common than multiple sinuses involvement, in isolated sinus most frequently involved are SSS and LS. Thus in most cases, occlusion involved at least two sinuses or sinus and cerebral veins. Among these, cortical veins were affected slightly more commonly than the deep venous system. These frequent associations probably explain, at least partly, why no good clinical-radiological correlations could be established.

CT venography has proved to be a reliable method to investigate the structure of the cerebral veins, with a reported sensitivity of 95% with multiplanar reformatted (MPR) images when compared with digital subtraction angiography (DSA) as the standard of reference5. Owing to its vascular detail and ease of interpretation, CT venography can provide a rapid and reliable diagnosis of cerebral venous thrombosis^16,17,18. The possibility of multiplanar reformations with CT venography is very helpful in detecting sinus and cortical venous thrombosis. CT venography with the integral display algorithm can provide an excellent demonstration of filling defects in the superficial venous sinuses and cortical veins. Volume rendering display can help demonstrate collateral pathways in cortical vein thrombosis. The most reliable criterion with which to establish the diagnosis of cavernous sinus thrombosis is the presence of a large filling defect of non–fat attenuation with sinus expansion¹⁹.

CSVT is an important and treatable cause of stroke, with risk factors such as OCP usage, alcoholism, and procoagulant condition becoming more well recognized in addition to traditional risk factors such as postpartum status. In this study, the most common risk factors for cerebral venous thrombosis were procoagulant status and infections. In comparison to other research, baseline investigations have a greater impact on CVT prognosis. The majority of the patients who were followed up had their occluded veins re-canalized. Only one patient died in the acute period, and only one patient manifested with recurrent CVT.

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