Current Status of Clinical Magnetic Resonance Imaging for Plaque Characterisation in Patients with Carotid Artery Stenosis

AbstractObjectiveThe article aims to provide an overview of the literature that assessed the agreement between magnetic resonance imaging (MRI) and histology for specific carotid plaque characteristics associated with vulnerability in terms of sensitivity and specificity.MethodsA systematic search strategy was conducted in MEDLINE and EMBASE databases resulting in 1084 articles. Finally, we included 17 papers. Due to variation in presentation, especially in MRI and histology methods, a pooled analysis could not be performed.ResultsTwo studies were performed on a 3.0-T MRI scanner; all other studies were performed on a 1.5-T scanner. Most performed sequences were two-dimensional (2D) and three-dimensional (3D) T1-weighted and all histology protocols varied slightly. Our results indicate that calcification, fibrous cap, intraplaque haemorrhage and lipid-rich necrotic cores can be identified with moderate-to-good sensitivity and specificity.ConclusionsBased on current literature, it appears premature for routine application of MRI as an imaging modality to assess carotid plaque characteristics associated with plaque vulnerability. Although MRI still holds promise, clinical application for plaque characterisation would require consensus regarding MRI settings and confirmation by histology. Predefined protocols for histology and MR imaging need to be established

Outcomes of Incisional Hernia Repair Surgery After Multiple Re-recurrences: A Propensity Score Matched Analysis

Background: Patients with a re-recurrent hernia may account for up to 20% of all incisional hernia (IH) patients. IH repair in this population may be complex due to an altered anatomical and biological situation as a result of previous procedures and outcomes of IH repair in this population have not been thoroughly assessed. This study aims to assess outcomes of IH repair by dedicated hernia surgeons in patients who have already had two or more re-recurrences. Methods: A propensity score matched analysis was performed using a registry-based, prospective cohort. Patients who underwent IH repair after ≥ 2 re-recurrences operated between 2011 and 2018 and who fulfilled 1 year follow-up visit were included. Patients with similar follow-up who underwent primary IH repair were propensity score matched (1:3) and served as control group. Patient baseline characteristics, surgical and functional outcomes were analyzed and compared between both groups. Results: Seventy-three patients operated on after ≥ 2 IH re-recurrences were matched to 219 patients undergoing primary IH repair. After propensity score matching, no significant differences in patient baseline characteristics were present between groups. The incidence of re-recurrence was similar between groups (≥ 2 re-recurrences: 25% versus control 24%, p = 0.811). The incidence of complications, as well as long-term pain, was similar between both groups. Conclusion: IH repair in patients who have experienced multiple re-recurrences results in outcomes comparable to patients operated for a primary IH with a similar risk profile. Further surgery in patients who have already experienced multiple hernia re-recurrences is justifiable when performed by a dedicated hernia surgeon

The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase

Instrumentatio

Risk stratification in asymptomatic and symptomatic patients with carotid artery stenosis

The overall aim of this thesis is to explore and assess the risks that patients with carotid artery disease, whether asymptomatic or symptomatic, are exposed to, and to explore whether patients that may be subject to relatively higher risk can be identified by imaging. Although large randomized trials have proven carotid endarterectomy (CEA) to be beneficial compared to best medical treatment alone, revascularization of patients with asymptomatic carotid artery stenosis (ACAS) remains a matter of debate. Therefore risk stratification of these patients is clinically important. First we identified that patients who suffered from ipsilateral cerebrovascular symptoms, but underwent CEA longer than 6 months after the index event, have a relatively unstable plaque composition compared to patients who never experienced ipsilateral symptoms. Second, patients with ACAS have a low risk of developing ischemic stroke. Patients with severe ACAS developing an occlusion were rare during long-term follow-up. However, occlusion was an independent prognostic risk factor for occurrence of stroke in this study. We showed in a pilot study of patients with severe ACAS that revascularisation slightly improved perfusion of the ipsilateral hemisphere as measured by ASL perfusion. However, clinical implication of this improved perfusion needs to be investigated in larger cohorts. For patients with symptomatic carotid artery stenosis CEA is the treatment of choice in patients with a severe (≥70%) stenosis. Surgery has been shown to be most effective in recurrent stroke prevention when performed within two weeks after transient ischemic attack (TIA) or ischemic stroke. In the UMC Utrecht delay to carotid surgery has shortened significantly over the years, but still exceeds 14 days in majority of patients. For further shortening of this delay specific attention should be paid to the pre-hospital phase. In literature, both CAS and CEA proved to be feasible revascularization techniques with low risk for TIA or stroke in patients with previous irradiation. Therefore the choice for revascularization therapy should be considered on an individual basis. Besides, we identified carotid stenotic lesions in patients with previous cervical radiation are less inflammatory and more fibrotic than carotid atherosclerotic lesions in non-radiated patients. The final part of this thesis outlines imaging of carotid artery stenosis. Before MRI can be routinely implemented in diagnostic work-up for these patients, clinical application for plaque characterisation would require consensus regarding MRI settings and confirmation by histology. This thesis has given more insight in risk management of the patient with carotid artery stenosis. Still, more research is warranted to accurately identify the specific risk groups in patients with carotid artery stenosis. Our studies and the suggested new research might result in more precise risk stratification for patients with carotid artery stenosis. We believe diagnosing and treating patients with carotid artery stenosis is a multidisciplinary, complex and ongoing process, which needs to be evaluated over time to keep up-to-date and sufficient