Intramural Hematoma Shape and Acute Cerebral Infarction in Intracranial Artery Dissection: A High-Resolution Magnetic Resonance Imaging Study

Imaging investigation of cervicocranial artery dissection by using high resolution magnetic resonance VWI and MRA: qualitative and quantitative analysis at different stages

BACKGROUND

To explore the value of magnetic resonance angiography (MRA) and high resolution magnetic resonance vessel wall imaging (HRMR-VWI) in cervicocranial artery dissection (CCAD) for the disease diagnosis, course staging and treatment. On the basis of qualitative evaluation, this study also extract the changes of different stages in vessel wall in different vessel segments to identify imaging indicators for the quantitative evaluation of CCAD.

METHODS

We retrospectively enrolled 34 patients with CCAD (38branches) with conventional MRA and HRMR-VWI examinations. Two radiologists independently analyzed imaging features of vessel wall and lumen in the different stages, and the typical sign detection of artery dissection were compared between MRA and HRMR-VWI. Then the parameters of vessel wall was quantitatively evaluated by the post-processing software (Vesselmass, Leiden University Medical Center, Leiden, The Netherlands.

RESULTS

HRMR-VWI revealed typical sign detection of artery dissection in all patients in the acute and subacute stage. Among them, the intimal flap/double lumen sign ditection were more common than the MRA, there was significant difference (P = 0.012). MRA revealed typical sign detection of artery dissection in more than half the patients, and the detection was no significant difference at the chronic stage between MRA and HRMR-VWI (P = 1.000/1.000/0.761). In the acute and subacute stage, the typical sign detection of intramural hematoma and Grade II enhancement revealed by HR-MRI was higher than the observations in the chronic stage (P = 0.000/0.000/0.016), while there was no significant difference by MRA (P = 0.902). The values of wall thickness, relative signal intensity of vessel wall enhancement, relative signal intensity of intramural hematoma (IMH), and percentage of stenosis in CCAD decreased from acute to subacute and then to chronic stages. Each quantitative parameter in patients with CCAD in the early stages (i.e., acute and subacute stages) was significantly different from that in patients with CCAD in the recovered group at chronic stage (P < 0.05). Wall thickness and relative signal intensity of vessel wall enhancement in patients with CCAD in the early stages were not significantly different from those in patients with CCAD in the incompletely recovered group at chronic stage (P > 0.05).

CONCLUSIONS

As the only noninvasive imaging technology, HRMR-VWI displays the structure of the vessel wall in vivo, showing not only excellent performance in the early diagnosis of CCAD, but also describing the changes of different stages in the qualitative and quantitative characteristics of vessel wall. It also helps to guide the diseasediagnosis, course staging and treatment of CCAD. Although the diagnostic efficacy of MRA was not as good as HRMR-VWI, it should be the first choice of method for routine examination in evaluating CCAD, especially at the chronic stage of CCAD.

Bilateral vertebral artery dissection extending to the left posterior cerebral artery: A case report

Intracranial artery dissection accounts for a small percentage (1%-2%) of all ischemic strokes. Vertebral artery dissection sometimes extends to the basilar artery but very rarely to the posterior cerebral artery. We report a case of bilateral vertebral artery dissection extending to the left posterior cerebral artery with the characteristic distribution of intramural hematoma. A 51-year-old woman presented with right hemiparesis and dysarthria 3 days after sudden neck pain. Magnetic resonance imaging on admission revealed infarcts in the left thalamus and temporo-occipital lobe and findings suggestive of bilateral vertebral artery dissection. No infarct was detected in the brainstem. The patient was treated conservatively. Initially, we suspected that infarction in the left posterior cerebral artery territory had been caused by artery-to-artery embolism from the dissected vertebral arteries. However, T1-weighted imaging on day 15 of admission revealed intramural hematoma extending from the left vertebral artery to the left posterior cerebral artery. Therefore, we diagnosed bilateral vertebral artery dissection extending to the basilar artery and the left posterior cerebral artery. The patient's symptoms subsequently improved with conservative treatment, and she was discharged with a modified Rankin Scale score of 1 on day 62 of admission. In this case, intramural hematoma of the basilar artery was found in the anterior vessel wall. Brainstem infarction is less likely when intramural hematoma is located in the anterior vessel wall of the basilar artery in vertebrobasilar artery dissection. T1-weighted imaging is useful for the diagnosis of this rare condition and can predict potentially impaired branches and possible symptoms.

Studying the imaging features and infarction mechanism of vertebrobasilar dolichoectasia with high-resolution magnetic resonance imaging

The mechanisms underlying ischemic infarction in patients with vertebrobasilar dolichoectasia (VBD) remain unclear. In this study, we retrospectively analyzed the imaging characteristics of high-resolution magnetic resonance imaging (HR-MRI) in patients with VBD to explore the possible mechanisms of ischemic stroke (IS) in patients with VBD. Patients with VBD were recruited from the HR-MRI database between July 2017 and June 2021. HR-MRI was used to evaluate the diameter, bifurcation height, laterality, arterial dissection, and atherosclerotic plaques of the basilar artery (BA). Transcranial Doppler was used to measure the vertebrobasilar mean velocity (Vm), peak systolic velocity (Vs), end-diastolic velocity (Vd), and pulsatile index. Twenty-six patients with VBD were enrolled, of which 15 had IS and 11 did not. The incidence of classical vascular risk factors, including age, sex, hypertension, diabetes, and hypercholesterolemia, did not differ significantly between the two groups. The BA diameters of the stroke group were significantly higher than that of the nonstroke group (6.57 ± 1.00 mm vs. 5.06 ± 0.50 mm, p = 0.000). The height of the BA bifurcation in the stroke and nonstroke groups was statistically significant (p = 0.002). Compared with the nonstroke group, the Vm, Vs, and Vd of the BA in the stroke group were lower, but the difference was not significant. In the 16 patients with atherosclerotic stenosis, 30 atherosclerotic plaques were found in the BA, 18 (60%) in the greater curvature, and 12 (40%) in the lesser curvature. In addition, one artery dissection (on the lesser curvature) and two dissecting aneurysms (on the greater curvature) were found in the BA of three patients, respectively. The BA diameter and bifurcation height are factors related to IS in patients with VBD. The mechanism of stroke in patients with VBD may involve abnormal hemodynamics, artery dissection, and atherosclerosis. HR-MRI is a useful method for evaluating the risk and underlying mechanism of stroke in patients with VBD.

Case report: Acute ischemic stroke caused by intracranial artery dissection in a patient with skull fractures

The intracranial artery dissection (IAD) is an uncommon but life-threatening disease. The IAD would develop a significant cerebral infarction due to unrecognized contrecoup brain injury. We report a 53-year-old man fell to develop blunt cerebrovascular injuries (BCVIs) more than 2 months ago. During his rehabilitation, he often had a transient left headache and underwent short-term right limb weakness twice, but he did not care. He was hospitalized again because of suffering right limb weakness for more than 4 h. The brain computed tomography angiography (CTA) showed subtotal occlusion of the left middle cerebral artery M1 segment, and the vascular morphology displayed the IAD. The patient was then treated with balloon dilation and a self-expanding stent. This case highlights that IAD may show delayed onset with no initial typical symptom. By early detecting of abnormal signs and symptoms, serious traumatic brain injury may be avoided.

Diagnostic accuracy of MR vessel wall imaging at 2 weeks to predict morphological healing of vertebral artery dissection

OBJECTIVES

The spontaneous healing of non-hemorrhagic intracranial vertebral artery dissection (VAD) may be associated with the stabilization of intramural hematoma (IMH). We previously suggested that the signal intensity of IMH increases until approximately 2 weeks in VAD with spontaneous healing. We herein investigated the diagnostic accuracy of the signal intensity of IMH at 2 weeks to predict the spontaneous healing of VAD.

METHODS

From April 2017 to April 2021, we prospectively investigated patients with non-hemorrhagic VAD who underwent vessel wall imaging (VWI). Morphological healing of VAD was evaluated by MR angiography three months after its onset. The relative signal intensity (RSI) of IMH against the posterior cervical muscle on VWI was calculated. Univariate and multivariate analyses were performed on factors associated with the spontaneous healing of VAD among patient baseline data, vascular morphology at the diagnosis, and RSI parameters.

RESULTS

Forty-eight patients (23 men and 25 women; mean age: 51 years, range: 34-73 years) with 50 non-hemorrhagic VAD were included in the present study. Spontaneous healing was observed in 28 VAD (56%). RSI two weeks after the onset of VAD (RSI_2w) and morphological feature such as the string sign were associated with spontaneous healing, respectively. The multivariate logistic regression analysis identified RSI_2w as an independent predictive factor of spontaneous healing (OR: 7.3; 95% CI, 1.9-28, p = 0.004). The cut-off value for RSI_2w to predict spontaneous healing was 1.22 (AUC = 0.90, sensitivity: 91%, specificity: 82%).

CONCLUSION

RSI_2w predicted the spontaneous healing of non-hemorrhagic VAD 3 months after its onset.

Association Between Autoimmune Diseases and Spontaneous Cervicocranial Arterial Dissection

A series of biopsies and reports showed autoimmune diseases might be involved in the process of local inflammation related to spontaneous cervicocranial arterial dissection (SCCAD) occurrence. This retrospective case-control study examined the association between SCCADs and autoimmune diseases in patients and control subjects from 2014 to 2020. SCCAD patients and age/sex-matched control subjects were recruited, and clinical data were collected. SCCAD was confirmed by digital subtraction angiography or high-resolution magnetic resonance imaging. The study included 215 SCCAD patients and 430 control subjects. Totally, 135 (62.8%) of the 215 cases were found SCCAD in the anterior circulation, 26 (12.0%) patients involved multiple vessels. Autoimmune disease occurred in 27 (12.6%) cases with SCCAD and 4 (0.9%) control subjects (p<0.001). A conditional multivariable logistic regression model was used to calculate the odds ratio for SCCAD among patients with a history of autoimmune disease, adjusting for hypertension, diabetes, hyperlipidemia, and smoking. After adjustment, autoimmune diseases were associated with SCCAD (p<0.001). After sub-analysis by a similar modeling strategy, significant associations were still observed in different subgroups, such as female group and male group as well as intramural hematoma (IMH) group and Non-IHM group. The association of SCCAD with autoimmune disease suggested that autoimmune mechanisms may be involved in some etiologies of SCCAD.

High-Resolution Magnetic Resonance Imaging (HR-MRI) Imaging Characteristics of Vertebral Artery Dissection with Negative MR Routine Scan and Hypoperfusion in Arterial Spin Labeling

Background

Unruptured vertebral artery dissection (VAD) that causes ischemic infarction may require anticoagulant therapy or other treatments. However, anticoagulation therapy is not recommended for patients without ischemic infarction. To date, there has been no research on the imaging characteristics of patients with ischemic hypoperfusion that have a negative routine MRI scan.

Material/Methods

Patients with suspected VAD were recruited between June 2015 and June 2020 in order to perform high-resolution magnetic resonance imaging (HR-MRI). In total, 26 patients with negative MRI routine scans that underwent arterial spin labeling (ASL) examination were included in the study. The patients were divided into the hypoperfusion group and normal group based on whether hypoperfusion was found in ASL. The clinical features and HR-MRI features between these 2 groups were analyzed.

Results

There were no statistical differences between the hypoperfusion group and normal group based on the patient’s clinical characteristics (P>0.05). According to imaging characteristics between the 2 groups, the effective lumen index and the vertebrobasilar artery minimum angle were statistically significant (P<0.001). Therefore, a vertebrobasilar artery minimum angle <90° was negatively correlated to the posterior circulation ischemia hypoperfusion, with a correlation coefficient of −0.686. The effective lumen index was also negatively correlated to the posterior circulation ischemia hypoperfusion, with a correlation coefficient of −0.671. However, the location of the dissection and other HR-MRI characteristics were not statistically significant between these 2 groups (P>0.05).

Conclusions

The hypoperfusion of posterior circulation ischemia caused by VAD is related to the effective lumen index, as well as the vertebrobasilar artery minimum angle.