Intracranial arterial dissections in ischemic stroke assessed by 3D rotational angiography

Arterial dissection as a cause of intracranial stenosis: A narrative review

Intracranial artery dissection (IAD) is an underdiagnosed, non-atherosclerotic cause of stroke with various clinical manifestations. To identify all the potential studies investigating the epidemiology, risk factors, symptoms, radiology findings, and treatment methods of IAD, we conducted a literature search screening PubMed, SCOPUS, EMBASE, and BIREME. According to the results of several studies, IAD is the major cause of ischemic stroke in at least one-third of the cervical-cranial artery dissection (CCAD) cases presenting with ischemic stroke. Mechanical causes are associated with cervical artery dissections (CAD) in up to 40 % of the cases. However, the risk factors for IAD are still not completely understood. Antithrombotic therapy with either antiplatelet or classic anticoagulants is the mainstay of treatment for preventing further thromboembolic complication after a stroke. Endovascular or surgical treatment options can be considered when medical therapies are not effective or when there is a high rate of recurrence or increased risk of bleeding. The observational studies have shown that these methods are very effective in preventing recurrence and significantly improving morbidity and mortality in patients with ruptured dissections. Clinical trials are required to establish the best option for each mechanism of ischemic lesion.

Application of low injection rate and low contrast agent dose in three-dimensional rotational digital subtraction angiography of the intracranial aneurysm

OBJECTIVE

The objective of this article is to explore the feasibility of low injection rate and low contrast agent dose in three-dimensional rotational digital subtraction angiography (3D DSA) of the intracranial aneurysm.

MATERIALS AND METHODS

Fifty-one patients with suspected intracranial aneurysms were included. The catheter tip was kept within the internal carotid artery at the epistropheus level. Patients were divided into three groups randomly according to injection rate: group A (1.5 ml/s, n = 18), group B (2.0 ml/s, n = 18), and group C (3.0 ml/s, n = 15). The noise, signal-to-noise ratio (SNR), and carrier-to-noise ratio (CNR) of C2, C6, M1, and A1 segments were calculated. The continuous subtraction images and reconstructed images were evaluated by two technicians.

RESULTS

No significant differences were found in noise between groups A and B, and groups A and C. Significant differences were found in the SNR and CNR of M1 and A1 segments between groups A and B, and groups B and C, but for C2 and C6 segments, they were not significant. Significant differences were found in the SNR and CNR of all segments between groups A and C. Significant differences were found in the contrast agent dose between all three groups. No significant differences were found in scores evaluated by two physicians between the three groups.

CONCLUSION

The personalized injection protocol of low injection rate and low contrast agent dose in 3D DSA of the intracranial aneurysm is feasible. The application of this protocol can reduce the dose of iodine and obtain satisfactory images.

Identification of internal carotid artery dissection by transoral carotid ultrasonography

BACKGROUND AND PURPOSE

Conventional transsurface carotid ultrasonography (TSCU) via the cervical surface often fails to detect dissection of the extracranial internal carotid artery (ICA). The role of transoral carotid ultrasonography (TOCU) in the detection of ICA dissection was examined.

METHOD

Patients with unilateral extracranial ICA dissection identified by digital subtraction angiography (DSA) from our database of patients with ischemic stroke or transient ischemic attack (TIA) were reviewed. Findings of dissection were compared between TSCU and TOCU.

RESULTS

Eight patients (7 men, 37-69 years old), including 7 with ischemic stroke and 1 with TIA, had ICA dissection. By DSA, dissection was identified between the first and third vertebrae in 4 patients and from the third cervical vertebra to the intracranial level in the remaining 4. TOCU images revealed an intimal flap as definite evidence of dissection in all patients. In 7 patients, color flow signals were not seen in false lumens, indicating thrombosed lumens. Four patients showed morphological changes of dissection on follow-up TOCU, including a patient with recovery of color flow signals in false lumens. The diameter of the dissected ICA was 7.3 ± 0.7 mm and that of the contralateral ICA was 4.9 ± 0.6 mm (p = 0.008). In contrast, TSCU did not enable any conclusive findings of ICA dissection to be made in any patient. Six patients had intramural hematoma on T(1)-weighted MRI, and 2 had an intimal flap with a double lumen on magnetic resonance angiography.

CONCLUSION

TOCU has advantages over TSCU in achieving an accurate diagnosis and follow-up evaluation of ICA dissection.