Stroke is the third leading cause of death in the United States. The degree of luminal narrowing evaluated by angiography is the standard for assessing the risk of stroke in patients with carotid atherosclerosis and for determining the need for surgical intervention. However, multiple studies have shown that clinical events arise not from the degree of stenosis but from the morphologic characteristics and plaque composition. This is borne out by the difference in absolute risk reduction between symptomatic and asymptomatic patients who receive surgical carotid endarterectomy (CEA). Future clinical practice may diagnose patients with high-risk atherosclerosis, based on plaque characteristics and morphology rather than the degree of stenosis alone. Carotid MRI is a noninvasive imaging method that can provide information on atherosclerotic plaque morphology, composition, and progression or regression. This chapter describes the current capabilities of MRI for visualizing carotid atherosclerosis, including MRI protocols to appropriately evaluate carotid plaque, the image features of carotid arteries, and the future direction of carotid MR imaging and how it can be better used for the management of patients with subclinical atherosclerosis, resulting in a higher quality of life.
Aneurysmal wall enhancement (AWE) has emerged as a new possible biomarker for depicting inflammation of the intracranial aneurysm (IA). However, the relationships of AWE with other risk factors are still unclear for unruptured IA. The purpose of this study was to investigate the association between AWE and other risk metrics.Forty-eight patients with unruptured saccular IAs diagnosed by digital subtraction angiography were recruited to undergo magnetic resonance (MR) black-blood imaging. AWE was evaluated using the pre- and post-contrast black-blood MR images. Univariate and multivariate logistic regression analysis was performed to investigate the association of AWE with other risk factors, including size, maximal neck width, parent vessel diameter, location, multiplicity, daughter sacs and other clinical factors. The prevalence of AWE in each ISUIA grade was reported and compared by Wilcoxon rank sum test.In total, 61 aneurysms were detected in 48 patients. Aneurysm size was found to be an independent risk factor associated with AWE (OR 2.46 per mm increase, 95% CI 1.34-4.51; p = 0.004). Patient age was independently and inversely associated with AWE (OR 0.898 per year increase, 95% CI 0.812-0.994; p = 0.037). Higher prevalence of AWE was observed in larger aneurysms (12%, 71.4%, 100%, and 100% of ISUIA grade 1-4 IAs have AWE, respectively). Notably, 12% of small IAs (size <7 mm) exhibited AWE. The IAs with AWE had significant higher ISUIA grade than the IAs without (p < 0.001, Wilcoxon rank sum test).The wall enhancement in contrast-enhanced black-blood MR images was independently associated with aneurysm size in unruptured IAs. However, some small unruptured aneurysms did exhibit wall enhancement, suggesting that AWE may provide additional aneurysm instability information to improve current size-based rupture risk evaluation metrics.
The association between haemoglobin A1c (HbA1c) and cerebral microbleeds (CMBs) remains unclear. We aimed to investigate the association between HbA1c and CMBs in community-based individuals without stroke or transient ischaemic attack (TIA) and whether the association differs between individuals with and without diabetes mellitus (DM).All individuals were recruited from a community in Beijing, China, from January 2015 to September 2019. All individuals completed a questionnaire and underwent blood tests and brain magnetic resonance imaging. A susceptibility-weighted imaging sequence was acquired to detect CMBs, which were defined as small, round and low-signal lesions with <10 mm diameter. The association between HbA1c and CMBs was analysed using multivariable logistic regression adjusted for demographics, medical history and blood sample test results. Subgroup analyses stratified by history of DM were performed.Of 544 recruited individuals, 119 (21.88%) had CMBs. HbA1c was independently associated with CMBs (odds ratio [OR], 1.51; 95% confidence interval [CI], 1.03-2.22). In 87 individuals with DM, multivariable logistic analysis showed that HbA1c was significantly associated with CMBs (OR, 1.67; 95% CI, 1.04-2.69), whereas in individuals without DM, no significant association was observed between HbA1c and CMBs (OR, 1.07; 95% CI, 0.50-2.30).HbA1c was associated with CMBs in individuals without stroke or TIA, particularly in individuals with DM, suggesting that the status of glycaemic control warrants attention for the prevention of CMBs. It would be beneficial to manage HbA1c specifically to control the risk of CMBs, especially in individuals with DM.
This is a retrospective study. The aim of this study was to determine the indicators of neurological outcome after surgery in patients with intramedullary spinal ependymomas by using magnetic resonance imaging (MRI).A total of 106 consecutive patients (mean age: 42.4 ± 1.3 years; 52.8% male) diagnosed with intramedullary spinal ependymomas were retrospectively recruited. All patients underwent spine MRI and subsequent surgical resection for the spinal tumors. Data regarding clinical symptoms and pathological grades of tumors were collected from clinical records. The McCormick score was used for grading patients' neurological status before and after surgery at 12 months. Good outcome was defined as stable McCormick score (McC) score (no change of McC score between preoperation and post-operation at 12 months) or improvement in McC score (post-operative McC score at 12 months < preoperative McC score). Poor outcome was determined when there was an increase in McC score at 12 months after surgery. The MRI characteristics of spinal ependymomas between patients with good and poor neurological outcomes were compared. Logistic regression was performed to assess the association between MRI characteristics of tumors and post-operative neurological outcomes.Patients with poor neurological outcomes had larger longitudinal length (4.7 ± 0.5 vs 3.3 ± 0.2, P = .004) and higher enhancement signal-to-noise-ratio (SNR) (102.4 ± 12.3 vs 72.8 ± 4.6, P = .022) than those with good neurological outcomes. After adjusting for confounding factors, longitudinal length (OR, 0.768; 95% CI, 0.604-0.976; P = .031) and enhancement SNR (OR, 0.988; 95% CI, 0.978-0.999; P = .026) of spinal ependymomas were significantly associated with poor neurological prognosis.The longitudinal length of tumor and enhancement SNR on T1-weighted images are independently associated with neurological outcome after surgery.
Neuropsychiatric manifestations, such as cognitive impairment, are relatively prevalent in systemic sclerosis (SSc) patients. This study aimed to investigate the resting state (RS) functional alternations of SSc patients and the potential influenced factors.
Quantification of vessel wall thickness is important in longitudinal monitoring of atherosclerosis. Black-blood MRI has been useful in measuring vessel wall thickness. Studies using two-dimensional (2D) imaging protocols measured wall thickness by matching the arterial wall and lumen boundaries on an acquisition plane. If the acquisition plane is oblique to the artery, the wall thickness would be overestimated by a factor that is dependent on the obliqueness angle. This problem can be understood as a three-dimensional (3D) surface mismatch problem, and we evaluated the effect of this problem by comparing the thickness measurements obtained using a 2D contour matching method and a 3D surface matching method. In addition to the surface mismatch problem, two other parameters may affect the wall thickness estimation: reslicing angle and slice thickness. We measured the wall thickness using images resliced perpendicular to the centerline of the vessel and quantified the difference between the thickness measurements obtained from parallel and centerline-based resliced images. Images obtained from a 2D MRI protocol typically have a slice thickness of 2mm, while the 3D MRI technique applied in this study produced images with sub-millimeter isotropic voxel size. To investigate the effect of slice thickness, we simulated 2mm-thick images by averaging the 3D black-blood image. Our results show that the wall thickness measured from 2mm-thick images was overestimated, especially in the carotid artery, which is associated with a larger obliqueness angle. This result underscores the advantage of the 3D isotropic acquisition technique in wall thickness measurement, especially in more tortuous vessels.
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