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 AND 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.

Massive Brainstem and Cerebellum Infarction Due to Traumatic Extracranial Vertebral Artery Dissection in a Motor Traffic Accident: An Autopsy Case Report.

ABSTRACT: Traumatic unilateral vertebral artery (VA) injury can cause focal thrombosis and may block the basilar artery which can further lead to ischemic stroke and massive cerebral infarction and subarachnoid hemorrhage and even rapid death. Here, we present an autopsy case with a traumatic extracranial VA dissection in a motor traffic accident, and the identification of cause of death underwent 2 autopsies. A 62-year-old male pedestrian collided with the right rearview mirror of a car and fell down to the ground. He complained pains in the head and neck. Head computed tomography (CT) showed a right linear temporal bone fracture and a small left temporal subdural hematoma. Neck CT and magnetic resonance imaging (MRI) examination showed left transverse process fracture of the sixth cervical vertebra (C6) and left extracranial VA injury. After 6 days of hospitalization, the left temporal subdural hematoma had been nearly absorbed, and the man was discharged home. On day 15 after the traffic accident, the man suffered sudden unconsciousness accompanied by frequent vomiting at home. The man was taken to hospital, and there were no obvious abnormal findings by head CT examination. However, the man soon fell into a coma state and died 2 days later. The first autopsy was performed 7 days after death and confirmed a left transverse process fracture of C6 and that the deceased died of cerebral infarction and secondary subarachnoid hemorrhage caused by blunt force in the motor traffic accident. In the civil lawsuit, the traffic accident wrecker put forward the objection whether the deceased had fatal diseases. The second autopsy (84 days after the death) findings verified the left extracranial VA injury. Histopathological examination further showed intimal dissection and thrombus formation of the left extracranial VA and secondary basal arterial thromboembolism. Massive infarction of the brainstem and cerebellum was disclosed. Therefore, the deceased died of delayed massive brainstem and cerebellum infarction because of left extracranial VA dissection in the motor traffic accident.

Predisposing factors and radiological features in patients with internal carotid artery dissection or vertebral artery dissection.

BACKGROUND: Cervicocerebral artery dissection is an important cause of ischemic stroke in young and middle-aged individuals. However, very few studies have compared the differential features between internal carotid artery dissection (ICAD) and vertebral artery dissection (VAD), including both cervical and intracranial artery dissections. We conducted a study to investigate the predisposing factors and radiological features in patients with ICAD or VAD. METHODS: All cases diagnosed with cervicocerebral artery dissection, ICAD, or VAD were identified through a medical records database, between January 2010 and January 2020. Baseline characteristics, predisposing factors, and radiological features of ICAD versus VAD were compared. RESULTS: A total of 140 patients with cervicocerebral artery dissection were included in the study, including 84 patients in the ICAD group and 56 in the VAD group. The mean age of patients in the ICAD and VAD groups was 43.37 ± 14.01 and 41.00 ± 12.98 years old, respectively. Patients with ICAD were more likely to be men compared with VAD (85.71% vs. 67.86%, p = 0.012). The frequency of hypertension, diabetes, smoking, drinking, and cervical trauma did not differ between ICAD and VAD. Dissections of ICAD were more frequently at the extracranial portions of the artery compared with those of VAD (70.24% vs. 44.64%, p = 0.003). In contrast, dissections of VAD were more common in the intracranial artery (55.36% vs. 29.76%, p = 0.003). Radiologically, double lumen (36.90% vs. 19.64%, p = 0.029) and intimal flap (11.90% vs. 1.79%, p = 0.029) were more frequently observed in ICAD than in VAD, and dissecting aneurysms were less frequent (13.10% vs. 26.79%, p = 0.041). CONCLUSIONS: The distributions of cervical and intracranial artery dissections were different between ICAD and VAD. The frequencies of radiological features detected in patients with ICAD and VAD also differed.

Traumatic cervical vertebral artery dissection: A case with cerebral infarct due to newly formed thrombus in the cerebral arteries.

We report a 50-year-old man who developed fatal brainstem infarction five days after traumatic cervical vertebral artery dissection (CVAD). Autopsy revealed multiple fresh infarcts in the territory of the vertebrobasilar system. No thrombus was found in the infarct lesions. The cervical vertebral artery (CVA) showed severe atherosclerotic stenosis extending to the proximal half of the left side, similar stenosis at the origin on the right side, fresh thrombotic occlusion extending to the proximal half of the right side, and multiple dissections in the distal foraminal segments on both sides. In the distal half of the basilar artery (BA) and the origin of the right posterior cerebral artery (PCA), the lumen was extensively filled with fresh thrombus. Although an intricate mixture of white and red thrombi filled the lumen at the origin of the right PCA, the white thrombus gradually appeared at the periphery whereas the red thrombus occupied the central and more proximal part of the BA. We confirm that cerebral infarction associated with CVAD is due not only to emboli originating from the dislodged thrombus at sites of arterial dissection, as reported previously, but also to newly formed thrombus in the cerebral arteries caused by impaired blood flow, as was seen in the present case.

Endovascular strategies for management of intradural vertebral artery dissecting aneurysms.

OBJECTIVE: Endovascular treatment of vertebral intradural dissecting aneurysms is complex and requires different strategies for each case. The current study aims to classify these aneurysms for an easy selection of optimal strategies for endovascular therapy. MATERIALS AND METHODS: This study is a retrospective evaluation of 10 patients harbouring a vertebral intradural dissecting aneurysm (including 6 female and 4 male patients). The clinical, procedural, and angiographic data were evaluated. RESULTS: Nine patients presented with acute subarachnoid hemorrhage and 1 with acute-onset headache. The aneurysms were classified into two types, depending on the developmental state of the contralateral vertebral artery: Dominant (A) and hypoplastic (B). Type A (n = 7) group was further divided into three subtypes on the basis of location of the aneurysm in relation to the posterior inferior cerebellar artery (PICA): aneurysm proximal to the PICA, Type I (n = 3); involving the PICA, Type II (n = 2); and, distal to the PICA, Type III (n = 2). Internal trapping was done for 4 patients in this group, 2 patients with aneurysm involving the PICA underwent proximal occlusion and 1 patient underwent stent-assisted coiling since he refused to undergo vertebral artery sacrifice. B Type patients (n = 3) were treated with reconstructive endovascular management. No symptomatic complication was seen in the patients with trapping. Antiplatelet medication-related complication was seen in 2 patients who underwent stent-assisted coiling. Clinical outcome at the time of discharge was good [modified Rankin score (mRS) 0-2] in 8 and poor (mRs >2) in 2 patients. At follow-up visit, one patient had developed severe cognitive impairment but was independent in activities of daily living. CONCLUSION: The classification of vertebral artery aneurysms based on their location and on the status of the contralateral vertebral artery appears to be an effective method for the selection of safe and appropriate endovascular therapy.

Utility of T1- and T2-Weighted High-Resolution Vessel Wall Imaging for the Diagnosis and Follow Up of Isolated Posterior Inferior Cerebellar Artery Dissection with Ischemic Stroke: Report of 4 Cases and Review of the Literature.

BACKGROUND: An accurate diagnosis of isolated posterior inferior cerebellar artery dissection (iPICA-D) is difficult due to the limitation of spatial resolution on conventional magnetic resonance imaging (MRI) techniques to detect subtle vessel wall abnormalities. The recent development of MRI techniques, including high-resolution vessel wall imaging (HRVWI), has resulted in the improved diagnostic accuracy and efficiency of iPICA-D. In fact, T1-weighted HRVWI, which can reveal intramural hematomas in the posterior inferior cerebellar artery (PICA), is useful for the diagnosis of iPICA-D. However, the utility of T2-weighted HRVWI has not been previously reported. The aim of this study was to investigate the diagnostic utility of T1- and T2-weighted HRVWI for the diagnosis of iPICA-D. METHODS: We retrospectively evaluated MRI findings including intramural hematomas, dilations, and chronological changes in 4 patients with iPICA-D admitted to our hospital and related facility from January 2015 to August 2016. In addition to T1-weighted HRVWI, T2-weighted HRVWI was performed on isovoxel three-dimensional (3D) fast spin-echo or 3D sampling perfection with application-optimized contrast using different flip-angle evolution. We also reviewed cases of nonhemorrhagic iPICA-D with ischemic onset in which the MRI findings were described. RESULTS: In all 4 patients, in addition to the intramural hematomas on T1-weighted HRVWI, T2-weighted HRVWI clearly showed the fusiform dilation of the external diameter of the PICA. T2-weighted HRVWI was more useful than other techniques, including T1-weighted HRVWI, for the evaluation of arterial shape changes. CONCLUSIONS: Like T1-weighted HRVWI, T2-weighted HRVWI is useful for the diagnosis and assessment of chronological changes in vessel wall abnormalities during the follow-up period.

Clinical Presentation, Magnetic Resonance Angiography, Ultrasound Findings, and Stroke Patterns in Patients with Vertebral Artery Dissection.

BACKGROUND/AIMS: Vertebral artery dissection (VAD) is an important cause of ischemic stroke. In this observational study, clinical data, magnetic resonance (MR) and ultrasound (US) imaging findings and ischemic patterns were analyzed. METHODS: Forty-seven patients with a diagnosis of VAD underwent clinical examination, US, MR of the brain and neck and MR angiography (MRA) of the cervical arteries. Vascular abnormalities and ischemic brain lesions were noted. Data were evaluated separately and compared for spontaneous and traumatic VAD subgroups. RESULTS: The most common overall clinical symptom was vertigo followed by neck pain. In the traumatic subgroup, vertigo was relatively rare (p = 0.022). Most common MRA findings were vessel irregularity and vessel occlusions. Ischemic lesions occurred significantly more frequently after spontaneous than after traumatic VAD (p = 0.009). Unilateral VAD was significantly more common in non-dominant vertebral arteries (p < 0.001). Mortality after trauma was not only due to VAD complications but also due to other trauma-related injuries. CONCLUSION: The variability of MR and US imaging findings in patients with VAD is illustrated. The algorithm of management should be based on a multimodality approach involving patient history and clinical neurological examination. Several types of vessel abnormalities and ischemic lesion in diverse locations may point to arterial dissection, and the differential diagnosis of VAD must be kept in mind.

Basilar dolichoectasia and the spontaneous intradural vertebral artery dissection.

OBJECT: Basilar dolichoectasia (BD) is an atherosclerotic, a distinct arteriopathy or a chronic-phase dissection characterized by elongation and dilation of the basilar artery. Spontaneous intradural vertebral artery dissection (siVAD) is an important cause of stroke in young and middle-aged people. It is hypothesized that the BD and the siVAD might partially share aetiologies and this study aimed to examine the relationship. METHODS: This study compared clinical and radiological characteristics in 93 patients with siVAD with 93 controls. Ectasia was defined as basilar artery diameter >4.5 mm and dolichosis, as either basilar artery bifurcation above the suprasellar cistern or lateral to the margin of the clivus or dorsum sellae. The BD was defined if both ectasia and dolichosis were simultaneously observed. Multivariate logistic regression analysis was performed using variables that were marginally or significantly associated with siVAD on univariate analysis (p < 0.20). RESULTS: Multivariate analysis showed siVAD patients have higher proportions of hypertension (OR = 2.4; 95% CI = 1.3-4.6; p = 0.007) and BD (OR = 3.7; 95% CI = 1.1-12; p = 0.036). CONCLUSIONS: The present study suggested that BD was related to the siVAD. A randomized study from multi-institutions with an adequate sample size is needed to make a strong argument about the association between BD and siVAD.

Characteristics and outcomes of patients with multiple cervical artery dissection.

BACKGROUND AND PURPOSE: Little is known about factors contributing to multiple rather than single cervical artery dissections (CeAD) and their associated prognosis. METHODS: We compared the baseline characteristics and short-term outcome of patients with multiple to single CeAD included in the multicenter Cervical Artery Dissection and Ischemic Stroke Patients (CADISP) study. RESULTS: Among the 983 patients with CeAD, 149 (15.2%) presented with multiple CeAD. Multiple CeADs were more often associated with cervical pain at admission (odds ratio [OR], 1.59; 95% confidence interval [CI], 1.10-2.30), a remote history of head or neck surgery (OR, 1.87; 95% CI, 1.16-3.00), a recent infection (OR, 1.71; 95% CI, 1.12-2.61), and cervical manipulation (OR, 2.23; 95% CI, 1.26-3.95). On imaging, cervical fibromuscular dysplasia (OR, 3.97; 95% CI, 2.04-7.74) and the presence of a pseudoaneurysm (OR, 2.91; 95% CI, 1.86-4.57) were more often seen in patients with multiple CeAD. The presence of multiple rather than single CeAD had no effect on functional 3-month outcome (modified Rankin Scale score, ≥3; 12% in multiple CeAD versus 11.9% in single CeAD; OR, 1.20; 95% CI, 0.60-2.41). CONCLUSIONS: In the largest published series of patients with CeAD, we highlighted significant differences between multiple and single artery involvement. Features suggestive of an underlying vasculopathy (fibromuscular dysplasia) and environmental triggers (recent infection, cervical manipulation, and a remote history of head or neck surgery) were preferentially associated with multiple CeAD.

Basilar extension and posterior inferior cerebellar artery involvement as risk factors for progression of the unruptured spontaneous intradural vertebral artery dissection.

BACKGROUND AND PURPOSE: Spontaneous intradural vertebral artery dissection (siVAD) primarily causes stroke in young and middle-aged individuals; however, data on the relationship between vertebrobasilar morphology and the progression of siVAD are limited. METHODS: We retrospectively reviewed the data of 77 adult patients who were diagnosed with unruptured siVAD and treated conservatively. We analysed the clinical characteristics, vertebrobasilar morphologies and progression. Progression was defined as siVAD-induced stroke or morphological worsening of the siVAD. RESULTS: Twenty patients experienced progression. Recurrent ischaemic events that occurred in the vertebrobasilar territory were seen in three patients (3.9%). Two of these three patients and other 17 patients showed morphological worsening. None of the patients presented with subarachnoid haemorrhage. The log-rank test showed male sex, migraine, basilar extension and the posterior inferior cerebellar artery involvement were associated with the progression. Multivariate analysis using the Cox proportional hazards model showed that only basilar extension and the posterior inferior cerebellar artery involvement were significantly related to the progression (p=0.012 and 0.019). In addition, patients with these two vertebrobasilar morphologies had a significantly shorter period of progression of siVAD than those without these morphologies (both, median 242 days; one of two, median 1292 days; none, median 2445 days). CONCLUSIONS: Thus, some vertebrobasilar morphologies might be markers of the progression of unruptured siVAD. Although all unruptured siVAD patients should be closely monitored, those with basilar extension and posterior inferior cerebellar artery involvement should perhaps be more carefully followed than those without such morphologies.

Comparison of potential risks between intracranial and extracranial vertebral artery dissections.

BACKGROUND/AIMS: To better understand potential risks for vertebral artery (VA) dissection (VAD), we compared intracranial and extracranial VADs. METHODS: We analyzed consecutively admitted VAD patients over a 9-year period in whom VAD was confirmed by angiography. All patients were categorized as having intracranial or extracranial VAD, and demographic and radiological characteristics of VAD were compared. We used multivariate analysis to predict the risks for intracranial and extracranial VADs. RESULTS: The study population (n = 74) had a mean age of 46.0 ± 10.3 years. VAD was more frequent in the nondominant VA (n = 49, 66.2%).Vertical nidus of VAD was more common in the intracranial segment (81.1%), and more particularly it was most frequently located within a 2-mm perimeter of the posterior inferior cerebellar artery (PICA) orifice (60.0%). Absence of traumatic history (OR 13.1, 95% CI 1.6-107.4; p = 0.016), history of hypertension (OR 14.1, 95% CI 1.1-184.6; p = 0.043)and aging (OR 1.1 per 1-year increase, 95% CI 1.0-1.2; p =0.038) were independent predictors of intracranial VAD. CONCLUSION: As compared to extracranial VAD, intracranial VAD was particularly frequent and particularly vulnerable at the perimeters of the PICA and nondominant VA and was associated with an absent trauma history, hypertension and aging. Formation of VAD appeared to be different according to intracranial or extracranial involvement.

A dilated surface appearance on basiparallel anatomic scanning-magnetic resonance imaging is a useful tool for the diagnosis of spontaneous vertebral artery dissection in lateral medullary infarction.

Spontaneous dissection of the vertebral artery (VA) is a major vascular lesion causing lateral medullary infarction (LMI). A dilated surface appearance of the VA is a feature of VA dissection and can be observed on basiparallel anatomic scanning (BPAS)-magnetic resonance imaging (MRI). The aim of this study was to validate BPAS-MRI in the diagnosis of VA dissection in patients with LMI. The subjects of the present study were 41 consecutive patients with LMI within 7 days of onset. The diagnosis of VA dissection was made with the clinical criteria-based diagnosis. Percent (%) dilatation of the VA on BPAS-MRI was calculated by comparing the maximum surface diameter of the intracranial VA to the diameter of the distal normal surface of the VA. Fourteen patients (34%) were diagnosed with VA dissection. The optimal cutoff % dilatation of the VA for dissection was more than 169%. The sensitivity and specificity of % dilatation of VA more than 169% and aneurysmal dilatation, stenosis, or occlusion on magnetic resonance angiography (MRA) for VA dissection were 92.9% and 81.5%, respectively. BPAS-MRI combined with time-of-flight-MRA is a useful tool for the diagnosis of VA dissection in patients with acute LMI.

Dermatomal sensory manifestations in lateral medullary infarction.

A 61-year-old man who experienced a sudden onset of unstable gait followed by nuchal pain was admitted to our department. The neurologic examination revealed right-sided limb ataxia, right partial ptosis, and decreased sensation to 50% of the normal side to pinprick and temperature stimuli on the left side below the level of the T-6 dermatome. A lateral medullary infarction caused by spontaneous vertebral artery dissection was diagnosed by magnetic resonance imaging and computed tomography angiography. In conclusion, lateral medullary infarction is an important entity to consider in the differential diagnosis of dermatomal sensory manifestations.

High-resolution magnetic resonance imaging reveals hidden etiologies of symptomatic vertebral arterial lesions.

BACKGROUND: Symptomatic intracranial vertebral artery (VA) disease has various clinical features and poor neurological outcomes. The disease is believed to result from atherosclerotic stenosis, occlusion, or spontaneous VA dissection. The underlying histopathology of symptomatic intracranial VA disease has only been studied at postmortem, and no in vivo imaging investigation has been conducted despite the increased sophistication of imaging techniques. METHODS: The authors performed high-resolution magnetic resonance imaging (HR-MRI) of intracranial vertebral arteries in 9 patients, suspected of a VA pathology by magnetic resonance imaging (MRI), magnetic resonance angiography, and digital subtraction angiography. RESULTS: HR-MRI allowed the authors to determine the following: (1) atherosclerotic plaque is composed of a large lipid core with intraplaque hemorrhage and calcification, (2) nonstenotic atherosclerosis exhibits diffuse vessel wall thickening and plaque protruding toward perforating arteries, and (3) spontaneous VA dissection exhibits large intramural hematoma in a false lumen with complete occlusion of the true lumen. In addition, VA hypoplasia was easily differentiated from atherosclerotic stenosis, by direct visualization of a narrow lumen diameter without arterial wall thickening. Furthermore, etiologic diagnoses based on classical MRI, angiography, and digital subtraction angiography were changed in 3 patients after HR-MRI. Additional information on plaque stability, indicating the possibility of unstable plaque, was found in 4 patients. CONCLUSIONS: The application of HR-MRI in stroke patients with VA pathologies enabled the authors to determine the underlying pathophysiologies. These findings could be used to improve risk stratification and treatment decision making in symptomatic intracranial VA disease.

Intramural hematoma detection by susceptibility-weighted imaging in intracranial vertebral artery dissection.

BACKGROUND: The radiologic diagnosis of vertebral artery dissection (VAD) depends on characteristic intraluminal findings on angiography and intramural hematoma or a double-lumen sign on high-resolution vessel wall imaging. We aimed to evaluate the accuracy of intramural hematoma sign on susceptibility-weighted imaging (SWI) in VAD. METHODS: We retrospectively analyzed SWI, phase map images and brain computed tomography (CT) of the consecutive patients who suffered an ischemic stroke in the vertebral artery territory from August 2010 to July 2012. We divided the patients into 2 groups: the VAD group and the nondissection group. VAD was diagnosed by conventional catheter angiographic findings (aneurysmal dilatation, pearl-and-string or tapered steno-occlusion) and pathognomonic findings such as intramural hematoma or a double-lumen sign on the source images of TOF-MRA, high-resolution T1-weighted MRI or high-resolution T2-weighted MRI. Intramural hematoma sign was considered positive if the patient had an eccentric or concentric hypointense signal lesion in the vertebral artery on SWI, a corresponding hyperintense signal on phase map and no evidence of calcification on the brain CT, suggesting blood products other than calcification. Two experienced neuroradiologists blinded to clinical information and angiographic findings were asked to judge for the presence of intramural hematoma sign on SWI. The accuracy of intramural hematoma sign on SWI was evaluated. Phase value, demographic and clinical data were compared between the VAD and the nondissection groups. RESULTS: Thirty-nine patients were included: 10 in the VAD group and 29 in the non-dissection group. Among the VAD group cases, intramural hematoma sign on SWI was positive in 9 of the 10 VAD cases and in 1 out of the 29 cases in the nondissection group. The intramural hematoma sign on SWI was significantly associated with VAD (p < 0.001), and showed sensitivity of 90% and specificity of 96.6%. Mean phase values of intramural hematomas (n = 9) were all positive and those of calcified lesions (n = 13) were all negative (0.45 radian vs. -0.42 radian, p < 0.001). CONCLUSIONS: The intramural hematoma sign on SWI was significantly associated with VAD and the phase map values were higher in intramural hematomas when compared with atherosclerotic calcifications.

3D fat-saturated T1 SPACE sequence for the diagnosis of cervical artery dissection.

INTRODUCTION: This study aims to demonstrate the added value of a 3D fat-saturated (FS) T1 sampling perfection with application-optimised contrast using different flip angle evolutions (SPACE) sequence compared to 2D FS T1 spin echo (SE) for the diagnosis of cervical artery dissection. METHODS: Thirty-one patients were prospectively evaluated on a 1.5-T MR system for a clinical suspicion of acute or subacute cervical artery dissection with 3D T1 SPACE sequence. In 23 cases, the axial 2D FS T1 SE sequence was also used; only these cases were subsequently analysed. Two neuroradiologists independently and blindly assessed the 2D and 3D T1 sequences. The presence of recent dissection (defined as a T1 hyperintensity in the vessel wall) and the quality of fat suppression were assessed. The final diagnosis was established in consensus, after reviewing all the imaging and clinical data. RESULTS: Overall sensitivity and specificity were 0.929 and 1 for axial T1 SE, and 0.965 and 0.945 for T1 SPACE (P > 0.05), respectively. The two readers had excellent agreement for both sequences (k = 1 and 0.8175 for T1 SE and T1 SPACE, respectively; P > 0.05). The quality of the fat saturation was similar. Very good fat saturation was obtained in the upper neck. Multiplanar reconstructions were very useful in tortuous regions, such as the atlas loop of the vertebral artery or the carotid petrous entry. 3D T1 SPACE sequence has a shorter acquisition time (3 min 25 s versus 5 min 32 s for one T1 SE sequence) and a larger coverage area. CONCLUSION: 3D T1 SPACE sequence offers similar information with its 2D counterpart, in a shorter acquisition time and larger coverage area.

MRI of intracranial vertebral artery dissection: evaluation of intramural haematoma using a black blood, variable-flip-angle 3D turbo spin-echo sequence.

INTRODUCTION: We investigated the efficacy of three-dimensional black blood T1-weighted imaging (3D-BB-T1WI) using a variable refocusing flip angle turbo spin-echo sequence in the diagnosis of intracranial vertebral artery dissection (VAD). METHODS: Sixteen consecutive patients diagnosed with intracranial VAD underwent magnetic resonance imaging that included 3D time-of-flight-MRA, axial spin-echo T1-weighted images (SE-T1WI) and oblique coronal 3D-BB-T1WI sequences. The visualization, morphology and extent of intramural haematomas were assessed and compared among the sequences. Results obtained by digital subtraction angiography (DSA), 3D-angiography and/or 3D-CT angiography (CTA) were used as standards of reference. RESULTS: 3D-BB-T1WI revealed intramural haematomas in all cases, whereas SE-T1WI and magnetic resonance angiography (MRA) failed to reveal a haematoma in one case and three cases, respectively. The mean visualization grading score for the intramural haematoma was the highest for 3D-BB-T1WI, and there was a statistically significant difference among the sequences (p < 0.001). At least a portion of the intramural haematoma was distinguishable from the lumen on 3D-BB-T1WI, whereas the haematomas were entirely indistinguishable from intraluminal signals on MRA in two cases (12.5%) and on SE-T1WI in one case (6.3%). 3D-BB-T1WI revealed the characteristic crescent shape of the intramural haematoma in 14 cases (87.5%), whereas SE-T1WI and MRA revealed a crescent shape in only 7 cases (43.8%) and 8 cases (50%), respectively. In a consensus reading, 3D-BB-T1WI was considered the most consistent sequence in representing the extent and morphology of the lesion in 14 cases (87.5%), compared to DSA and CTA. CONCLUSION: 3D-BB-T1WI is a promising method to evaluate intramural haematoma in patients with suspected intracranial VAD.

Intracranial segmental arterial mediolysis: report of 2 cases and review of the literature.

Extensive nontraumatic subarachnoid hemorrhage is an important cause of unexpected death in young adults. Segmental arterial mediolysis (SAM) represents an uncommon pathologic finding in the intracranial blood vessels associated with this type of hemorrhage. Segmental arterial mediolysis is a pathologic entity with putative vasospastic etiology, which recently has been reported to be associated with Ehlers-Danlos syndrome type 4. We describe 2 additional cases of ruptured intracranial vertebral artery with features of SAM that resulted in fatal subarachnoid hemorrhage. We also review the literature on vessels with features of SAM that are either intracranial or affecting the internal carotid artery with major direct effects (ie, stroke or transient ischemic attack) on the central nervous system.

Differences in vertebrobasilar artery morphology between spontaneous intradural vertebral artery dissections with and without subarachnoid hemorrhage.

BACKGROUND: Patients with spontaneous intradural vertebral artery dissection (siVAD) developing subarachnoid hemorrhage (SAH) have been observed to have poor outcomes. Factors predisposing siVAD patients to SAH are not well known. We aimed to investigate the clinical and vertebrobasilar artery morphological characteristics associated with SAH in patients with siVAD. METHODS: We reviewed 103 consecutive patients with siVAD managed at our facility between July 2003 and June 2012. We divided the patients into groups, with (n = 22) and without (n = 81) SAH, and compared clinical and vertebrobasilar artery morphological characteristics between them. The vertebral-union-basilar angle (VUBA) was defined as the most acute angle between the line of the basilar artery trunk and the line of the vertebral artery at the vertebral union on 3-dimensional magnetic resonance angiography, computed tomographic angiography, or digital subtraction angiography. 'Steep vertebral artery' was defined as VUBA >45°. Basilar artery bending was defined as the longest distance from the line which connected the basilar top and vertebral artery union to the greatest bending point of the basilar artery. RESULTS: Stepwise logistic regression analysis was performed using variables that were marginally or significantly associated with SAH on univariate analysis (p < 0.10) and that were thought to be clinically important for SAH. It showed SAH patients to have significantly higher proportions of current smoking (OR: 7.7; 95% CI: 2.7-22; p = 0.0015), dissection of the dominant vertebral artery (OR: 4.9; 95% CI: 1.8-13; p = 0.043), steep vertebral artery of the dissecting side (OR: 7.2; 95% CI: 2.6-20; p = 0.0023), posterior inferior cerebellar artery involvement (OR: 4.0; 95% CI: 1.3-13; p = 0.011), basilar artery bending <3 mm (OR: 3.4; 95% CI: 1.3-9.5; p = 0.0040), and pearl-and-string sign (OR: 5.7; 95% CI: 2.0-16; p = 0.0033). CONCLUSIONS: We suggest that the clinical and vertebrobasilar artery morphological characteristics demonstrated in the present study may be related to SAH induced by siVAD. Although all patients with siVAD should be closely monitored, those with siVAD who have these characteristics should perhaps be more closely followed than those who do not have such features.