Diagnosis and follow-up of posterior inferior cerebellar artery dissection complicated with ischemic stroke assisted by T1-VISTA: a report of two cases

Usefulness of combining CISS and digital subtraction angiography in diagnosis of isolated posterior inferior cerebellar artery dissection

A 63-year-old man was admitted to our stroke center with brain infarction in the left posterior inferior cerebellar artery (PICA) territory. The initial MRI showed no findings suggestive of arterial dissection, and post-discharge MRI showed no temporal changes. Digital subtraction angiography (DSA) revealed vasodilation of the proximal portion of the PICA but it was uncertain whether dissection was present. Discrepancy between the outer contour seen on constructive interference in steady state (CISS) MRI and the inner contour seen on DSA suggested the presence of intramural hematoma. The patient was diagnosed with brain infarction caused by isolated PICA dissection (iPICAD). Imaging evaluation of combined CISS and DSA may be particularly useful for identification of small iPICAD lesions.

Traumatic dissection of the anterior cerebral artery secondary to a rugby related impact: A case report with emphasis on the usefulness of T1-VISTA

Background

Cerebrovascular injuries (CVIs) are not usually considered in the differential diagnosis of sport-related head injuries (SRHIs). We encountered a rugby player with traumatic dissection of the anterior cerebral artery (ACA) after impact on the forehead. Head magnetic resonance imaging (MRI) with T1-volume isotropic turbo spin-echo acquisition (VISTA) was used to diagnose the patient.

Case Description

The patient was a 21-year-old man. During a rugby tackle, his forehead collided with the forehead of an opponent. He did not have a headache or disturbance of consciousness immediately after the SRHI. On the 2^nd day of illness, he had transient weakness of the left lower limb several times. On the 3^rd day of illness, he visited our hospital. MRI revealed occlusion of the right ACA and acute infarction of the right medial frontal lobe. T1-VISTA revealed intramural hematoma of the occluded artery. He was diagnosed with acute cerebral infarction due to dissection of the ACA and was followed up for vascular changes with T1-VISTA. The vessel had recanalized and the size of the intramural hematoma had decreased 1 and 3 months after the SRHI, respectively.

Conclusion

Accurate detection of morphological changes in cerebral arteries is important for the diagnosis of intracranial vascular injuries. When paralysis or sensory deficits occur after SRHIs, it is difficult to differentiate between concussion from CVI. Athletes with red-flag symptoms after SRHIs should not merely be suspected to have concussion; they should be considered for imaging studies.

Isolated posterior inferior cerebellar artery dissection with ischaemic stroke: evaluating the radiological features and diagnostic feasibility of high-resolution vessel wall imaging

AIM

To evaluate the radiological features of isolated posterior inferior cerebellar artery dissection (PICAD) and the feasibility of using high-resolution vessel-wall imaging (HR-VWI) for diagnosing PICAD.

MATERIALS AND METHODS

Three hundred and nine patients with arterial dissection involving the posterior cerebral circulation, who underwent HR-VWI between March 2012 and July 2019 were reviewed retrospectively. Among them, 44 patients (14.2%) were diagnosed with isolated PICAD in consensus among a neuroradiologist, a neurointerventionist, and a neurologist. Two neuroradiologists reviewed the vessel wall images independently for evidence of dissection (dissection flap, outer diameter enlargement on T2-weighted imaging [WI], mural haematoma). Diagnostic confidence was also scored on a five-point scale. Intra- and interobserver agreement for diagnosing PICAD and detecting evidence of dissection were evaluated.

RESULTS

Dissection flaps were seen on T2WI in all cases (100%) and on contrast-enhanced T1WI in 34 patients (79.1%). Outer diameter enlargement of the steno-occlusive lesions on angiography was detected in most cases (97.7%). A mural haematoma was detected on three-dimensional (3D) contrast-enhanced motion-sensitised driven-equilibrium T1WI in 97.1% of the cases. The mean diagnostic confidence score derived by two neuroradiologists was 4.72. The two reviewers showed substantial to almost perfect agreement (weighted kappa coefficient: 0.62-0.97).

CONCLUSION

Use of HR-VWI as a diagnostic tool for PICAD is feasible, and a dissection flap with outer wall enlargement on HR-T2WI allows confident dissection diagnosis. The present data suggest that PICAD might be considered as a stroke aetiology in patients with unexplained ischaemic stroke in the PICA territory, and that PICA evaluation with HR-VWI is both necessary and feasible.

Utility of T2-weighted high-resolution vessel wall imaging for the diagnosis of isolated posterior inferior cerebellar artery dissection at acute and early subacute stages

Recent advances in magnetic resonance high-resolution vessel wall imaging (HRVWI), which can detect intramural hematomas (IMH), improve the noninvasive diagnostic accuracy of isolated posterior inferior cerebellar artery dissection (iPICA-D). However, despite the risk of overlooking minute IMH, the utility of T2-weighted HRVWI has not been thoroughly evaluated. This study aimed to compare the utility of T2-weighted HRVWI with that of T1-weighted HRVWI, basiparallel anatomical scanning (BPAS), and magnetic resonance angiography (MRA) for the diagnosis of iPICA-D mainly in the acute and early subacute stages in 6 iPICA-D patients (three acute, two early subacute and one late subacute stages on initial examinations). Dissection-related abnormalities included IMH on T1-weighted HRVWI, aneurysmal dilations on T2-weighted HRVWI and discrepancy between BPAS and MRA. On initial examinations, T2-weighted HRVWI revealed iPICA-D-related abnormalities more conspicuously than did T1-weighted HRVWI and combination of BPAS and MRA. Except in a single case with a discrepancy between the outer contour on BPAS and inner contour on MRA, no specific abnormalities were detected besides T2-weighted HRVWI at acute or early subacute stages. In addition to T1-weighted HRVWI, BPAS and MRA, T2-weighted HRVWI should be performed to diagnose acute and early subacute iPICA-D.

Qualitative Assessment and Reporting Quality of Intracranial Vessel Wall MR Imaging Studies: A Systematic Review

BACKGROUND

Over the last quarter-century, the number of publications using vessel wall MR imaging has increased. Although many narrative reviews offer insight into technique and diagnostic applications, a systematic review of publication trends and reporting quality has not been conducted to identify unmet needs and future directions.

PURPOSE

We aimed to identify which intracranial vasculopathies need more data and to highlight areas of strengths and weaknesses in reporting.

DATA SOURCES

PubMed, EMBASE, and MEDLINE databases were searched up to September 2018 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

DATA ANALYSIS

Two independent reviewers screened and extracted data from 128 articles. The Strengthening the Reporting of Observational Studies in Epidemiology guidelines were used to assess the reporting quality of analytic observational studies.

DATA SYNTHESIS

There has been an exponentially increasing trend in the number of vessel wall MR imaging publications during the past 24 years (P < .0001). Intracranial atherosclerosis is the most commonly studied intracranial vasculopathy (49%), followed by dissections (13%), aneurysms (8%), and vasculitis (5%). Analytic observational study designs composed 48% of the studies. Transcontinental collaborations showed nonsignificantly higher reporting quality compared with work originating from single continents (P = .20).

LIMITATIONS

A limitation is the heterogeneity in study designs.

CONCLUSIONS

Investigations on the diagnostic utility of vessel wall MR imaging in less commonly studied intracranial vasculopathies such as dissections, aneurysms, and vasculitis are warranted. More consistent adherence to the Strengthening the Reporting of Observational Studies in Epidemiology guidelines should improve transparency and maximize effective synthesis for clinical translation. Diverse collaborative teams are encouraged to advance the understanding of intracranial vasculopathies using vessel wall MR imaging.

Intimal flap detected by three-dimensional curved multiplanar reconstruction image in isolated posterior inferior cerebellar artery dissection: a report of two cases

BACKGROUND

Spontaneous isolated posterior inferior cerebellar artery (PICA) dissection has been reported more frequently since high-resolution vessel wall magnetic resonance imaging (HR vw-MRI) was introduced to the field. The intimal flap or double lumen, which is commonly reported to be a direct sign of the dissection, is not easily detectable on HR vw-MRI because the size of the PICA is very small and tortuous.

CASE PRESENTATION

Two patients with posterior circulation ischemic stroke due to spontaneous isolated PICA dissection underwent HR vw-MRI. The curved multiplanar reconstruction image reconstructed using three-dimensional (3D) HR vw-MRI (3D curved MPR imaging) is helpful to observe tortuous blood vessels such as the PICA because it can visualize the entire vessel course in a single plane. In this report, routine HR vw-MRI revealed only an intramural hematoma in both patients. However, 3D curved MPR imaging discovered the intimal flap which was not observed on the routine HR vw-MRI. Therefore, these two patients were diagnosed with spontaneous isolated PICA dissection due to the intimal flap that was observed on the 3D curved MPR image.

CONCLUSION

HR vw-MRI is useful for the early diagnosis of isolated PICA dissection. Furthermore, we believe that 3D curved MPR imaging could improve the possibility of diagnosing the dissection early because it can easily confirm direct signs such as an intimal flap or double lumen.

Utility of the variable flip angle 3D fast-spin echo (isoFSE) sequence on 3T MR for diagnosing vertebrobasilar artery dissection

We aimed to investigate the utility of the isoFSE sequence, one of the variable flip angle 3D fast-spin echo sequences, on 3T-MR for displaying vessel walls and diagnosing vertebrobasilar artery dissection (VAD). We retrospectively evaluated 12 initial and 28 follow-up images from 12 patients diagnosed with either intracranial VAD or carotid artery dissection. The image quality for displaying the vessel wall was scored using a five-point scale (1 poor, 5 excellent) on initial T1-weighted isoFSE images for each region of the arteries. The intracranial artery dissection findings assessed at time points after onset were evaluated on initial and follow-up T1/T2-weighted isoFSE images. For small arteries, including the anterior/posterior inferior cerebellar artery, similar high scores were obtained on both unenhanced and contrast-enhanced T1-weighted isoFSE images (average: 4.7-5.0, p > 0.2). On unenhanced images, dissected vertebral arteries showed significantly lower scores than non-dissected vertebral arteries for both readers (p = 0.017 and 0.015, respectively), but the scores were high (3.9 and 4.0, respectively). Definitive findings of VAD were observed on the initial images except in one case. For all cases, definitive findings were seen on at least one of the initial or follow-up images. Temporal changes in the findings could be observed for all cases. In conclusion, we showed favorable wall visualization on T1-weighted isoFSE images and the utility of follow-up imaging using unenhanced-T1/T2-weighted and contrast-enhanced T1-weighted isoFSE sequences with acceptable scan times, which could promote the regular use of 3D black-blood vessel wall imaging.

Clinical Characteristics of Cerebellar Infarction Due to Arterial Dissection

Objectives and Background:

Arterial dissection (AD) of the vertebral artery (VA) or its branches may cause ischemic stroke of the posterior circulation. However, clinical and radiological characteristics of patients with AD-related cerebellar infarction (CI) have rarely been reported.

Methods:

Forty-nine patients with CI admitted to our department from April 2008 to March 2015 were identified from our database. After dichotomization into the AD and non-AD group, their demographics and presenting symptoms were compared. Subsequently, a multivariate regression analysis was performed to identify variables that correlated with AD.

Results:

During the 7-year period, 14 and 35 patients were identified in the AD and non-AD group, respectively. The AD group was significantly younger than the non-AD group (55.0 ± 16.3 vs. 69.7 ± 10.7 years, P = 0.001) and was also more likely to experience acute pain at onset (86% vs. 17%, P < 0.001). Using a multivariate regression analysis, these two variables and the male sex were found to correlate with AD. AD was located in extracranial VA (n = 3); intracranial VA (n = 8); posterior inferior cerebellar artery (PICA) (n = 3); and superior cerebellar artery (n = 1). Identification of AD was delayed in one patient with an extracranial VA and one patient with a PICA dissection.

Conclusions:

AD was responsible for approximately 30% of CI in our cohort. Pain at onset may be a useful symptom to identify patients with AD-related CI. While intracranial VA was the most common location of AD, physicians should be aware of the possibility of extracranial VA or PICA dissection in patients with seemingly unremarkable radiological findings.

Malignant Cerebral Swelling After Cranioplasty due to Ipsilateral Intracranial Vasculopathy: Case Report and Literature Review

BACKGROUND

Cranioplasty is a well-established surgical operation that is used worldwide for patients with skull defects following decompressive craniectomy (DC). However, in some cases, potentially fatal complications may occur, such as malignant cerebral swelling after uneventful cranioplasty.

CASE DESCRIPTION

We present a rare case of massive malignant ipsilateral cerebral swelling following uneventful titanium mesh cranioplasty due to rare ipsilateral intracranial vasculopathy confirmed by magnetic resonance angiography (MRA) and magnetic resonance venography (MRV). Fortunately, we performed titanium mesh explantation and extended DC in time, and the patient survived. Malignant cerebral swelling after uneventful cranioplasty is an unpredictable but fatal complication. Most reported cases have had an unfavorable prognosis. To the best of our knowledge, the mechanism was first confirmed by MRA and MRV, which demonstrated that the cerebral swelling was due to unilateral intracranial vasculopathy, including a rare ipsilateral intracranial internal carotid artery occlusion, as well as extremely thin lateral and sigmoid sinuses.

CONCLUSIONS

Our case demonstrates for the first time that ipsilateral intracranial vasculopathy is a risk factor for malignant cerebral swelling after cranioplasty. Patients with traumatic brain injury with suspected intracranial vasculopathy should undergo a comprehensive vascular evaluation before cranioplasty to help prevent malignant cerebral swelling.