Cortical Watershed Infarction Research Articles

Clinico-Radiological-Pathological Correlation of Visual Loss in COVID-Associated Rhino-Orbito-Cerebral Mucormycosis.

Purpose:To correlate the clinical, radiological, and histopathological features in Covid-associated Rhino-orbito-cerebral mucormycosis cases presenting with acute visual loss.Design:Cross-sectional study.Methods:Covid-associated Rhino-orbito-cerebral mucormycosis cases with unilateral visual loss, planned for exenteration, underwent orbital and ophthalmological ocular examination. The available radiological sequences, doppler ultrasonography and histopathology findings were correlated with clinical manifestations.Results:The median age was 51 years and the male: female ratio was 3:1. All except one presented with unilateral ophthalmoplegia. The ocular media were hazy in 2 eyes. In 8 eyes, retinal changes were suggestive of occlusion of CRA (6), combined occlusion of CRA and central retinal vein (1), and myopic degeneration with hypertensive retinopathy (1). The contralateral eye showed retinal ischemic changes in one patient. Radiological imaging showed orbital apex involvement in the 10 affected eyes and one contralateral eye. Ipsilateral cavernous sinus thrombosis, diffusion restriction on MRI of optic nerve, internal carotid artery narrowing/thrombosis, and cortical watershed infarcts were seen in 8, 4, 4, and 2 cases, respectively. The blood flow in CRA and ophthalmic artery was absent or reduced in all the 10 affected eyes and in 1 contralateral eye. On histopathology, orbital fat necrosis, fungal hyphae, acute inflammation, granuloma formation, ischemic thrombosis of ophthalmic artery was observed in 10 specimens. CRA was patent in 9 and thrombosed in 1 eye. Optic nerve was ischemic in 8 and viable in 2 eyes.Conclusion:Acute visual loss in ROCM cases is associated with orbital apex involvement and thrombotic ischemia of ophthalmic artery. Cessation of flow in CRA possibly occurs secondary to ophthalmic artery thrombosis.

Double Mandibular Osteotomy for Access to High-Carotid Pathology

Anecdotal experience demonstrates the existence of patients with superiorly located carotid stenosis, neoplasms, or aneurysms where the mandible obstructs effective surgical access using standard techniques. As carotid pathology extends anatomically beyond the limits of standard operative technique, additional exposure becomes paramount to safely and effectively address the lesion. Double mandibular osteotomy (DMO) is one of several techniques to obtain additional exposure to high-carotid pathology; however, there is no large series to address the outcomes of patients undergoing this procedure. A retrospective case series was performed for all patients undergoing surgery for carotid pathology from 2011-2019 that could not be approached with standard cervical incision. The primary predictor variable was high-anatomic carotid pathology necessitating DMO. The primary outcome variable was early and late complications sustained by patients. Fifteen patients met study criteria and underwent 16 DMOs to access high-carotid pathology including carotid stenosis (n=8 patients), carotid aneurysm (n=2 patients), and carotid body tumor (n=8 patients). Two patients had dual ipsilateral pathology with one patient having both carotid artery stenosis and aneurysm, and the other patient diagnosed with carotid artery stenosis and carotid body tumor. One patient had bilateral carotid artery stenosis, each requiring high anatomic exposure for treatment. Early complications occurred in 8 patients. Five patients experienced significant dysphagia requiring enteral feeding, and 2 patients developed malocclusion directly related to the double mandibular osteotomy. One patient experienced contralateral cortical watershed infarcts. Late complications included one patient developing osteomyelitis of the mandible, and this patient also developed distal mandibular segment screw exposure. The comparison of the outcome groups for categorical predictor variables using Fisher's exact test detected no statistically significant differences for gender, hypertension, hyperlipidemia, type 2 diabetes, chronic obstructive pulmonary disease, tobacco use, chronic kidney disease, or cerebrovascular disease. For the continuous variable comparisons, independent-samples t-tests detected no difference between the complication groups for age, operative time, or years of follow-up. No significant differences were found between the groups for body mass index or intraoperative blood loss. The double mandibular osteotomy provides excellent exposure and surgical access to the distal internal carotid artery for repair of vascular pathology with acceptable outcomes and long-term complications compared with previously reported techniques. Because of the early complications realized with the DMO, we recommend the procedure for symptomatic patients with a high risk of failing medical therapy alone and not appropriate for endovascular treatment as well as those patients with tumors requiring surgical intervention.

Clinical features and the degree of cerebrovascular stenosis in different types and subtypes of cerebral watershed infarction

BackgroundWhether there are differences in pathogenesis among different types and subtypes of cerebral watershed infarction (WSI) is controversial since they have been combined into a single group in most previous studies.MethodsWe prospectively identified 340 supratentorial WSI patients at Beijing Chao-Yang Hospital, Capital Medical University, China and classified them based on diffusion-weighted imaging(DWI) templates. Baseline characteristics, clinical courses and neuroradiological features were compared among patients with different types and subtypes of WSI.ResultsWe identified 92 patients with cortical watershed infarction (CWI), 112 with internal watershed infarction (IWI) and 136 with mixed-type infarction. Compared with CWI patients, more IWI patients had critical stenosis of internal carotid artery (ICA) (P < 0.001). For the CWI group, patients with anterior watershed infarction (AWI) were more prone to critical ICA stenosis than those with posterior watershed infarction (PWI) (P = 0.011). For the IWI group, critical ICA stenosis was more prevalent in patients with partial IWI (P-IWI) than in those with confluent IWI (C-IWI) (P = 0.026). IWI patients were more frequently found to have clinical deterioration during the first 7 days of hospitalization and a poor prognosis at the 90th day than in CWI patients (P = 0.003 and P = 0.014, respectively).ConclusionsIWI, especially the P-IWI subtype, is associated with hemodynamic impairment (HDI), whereas CWI has a weaker correlation with ICA steno-occlusion. Furthermore, IWI patients are more prone to poor prognosis.

Patterns of Acute Ischemic Strokes After Carotid Endarterectomy and Therapeutic Implications.

Acute ischemic strokes following surgical treatment of carotid stenosis lead to substantial disability and mortality, and vascular mechanisms underlying their development are not fully elucidated. The goal of this study was to analyze the topographic patterns of acute ischemic stroke following carotid endarterectomy (CEA) on diffusion-weighted and perfusion-weighted magnetic resonance imaging (MRI). Data were retrospectively collected from consecutive patients who underwent CEA and developed postoperative acute ischemic stroke. Based on the MRI data sets, the lesion patterns of acute stoke were characterized. Morphology of the circle of Willis, the 3-D time-of-flight (3D-TOF) of the cerebral arteries, and status of the carotid circulation were also analyzed in order to determine the vascular mechanisms involved in stroke development. Between January 2008 and May 2015, 821 patients were treated surgically for a symptomatic or asymptomatic carotid stenosis at the University Hospital of Nice. Nineteen (2.3%) patients had an acute ischemic stroke after surgery. Among them, 11 (57.9%) patients had a territorial infarction and 8 (42.1%) patients had an internal watershed infarction, cortical watershed infarction, or mixed border zone infarction. According to imaging data sets, embolic mechanism of stroke was reported for 12 (63.2%) patients, hemodynamic mechanism for 2 (10.5%) patients, and mixed mechanism for 5 (26.3%) patients. An asymmetry on 3D-TOF was observed in 60% and 50% of patients with hemodynamic and mixed stroke and in 25% of patients with embolic stroke. The latter 2 patients with embolic stroke underwent successful mechanical thrombectomy using stent-retriever devices. In this cohort, embolic mechanism leading to postoperative stroke was more frequently observed than hemodynamic mechanism. Immediate characterization of the cerebral lesion by postoperative brain MRI is of utmost importance because it may rapidly identify patients eligible for treatments such as mechanical thrombectomy.

The Pathophysiology of Watershed Infarction: A Three-Dimensional Time-of-Flight Magnetic Resonance Angiography Study

Most of the time, watershed infarcts (WIs) involve steno-occlusive carotid disease. The pathophysiological mechanism could be predicted by their pattern: internal WIs (IWIs) are thought to be due to hemodynamic impairment in contrast to cortical WIs (CWIs), which are more likely to be caused by microembolic phenomena. We used a 3D time-of-flight (TOF) magnetic resonance angiography (MRA) study to assess this hypothesis. In 45 consecutive patients with a recent WI and ipsilateral cervical carotid stenosis, clinical and radiological data were obtained retrospectively. 3D TOF MRA were analyzed both qualitatively and quantitatively (internal carotid and anterior, middle and posterior cerebral arteries). Then, 2 groups were determined depending on their radiological patterns: WIs with (IWI+) or without (IWI-) an internal watershed. Thirty-two of the 45 patients (71%) had IWIs that were or were not associated with CWIs (IWI+), while 13 patients (29%) had only CWIs (IWI-). There was no significant relationship between the radiological pattern and the demographic data, the cardiovascular risk factors, or the degree of stenosis. However, IWI+ patients more frequently had motor weakness (P = .03) than CWI patients. An ipsilateral reduced middle cerebral artery intensity on 3D TOF MRA in both qualitative and quantitative analyses was significantly associated with IWI+. Instead within IWI-, no significantly reduced signal intensity was found. These findings originally support the view that IWIs are mainly caused by a hemodynamic impairment related to carotid stenosis, whereas CWIs are mostly due to a microembolic mechanism. 3D TOF MRA, which gives pertinent information on pathophysiology on IWIs, can help in decision making.

基于穿支动脉-神经组织单元论分水岭脑梗死分型及脑白质疏松的形成

At present, there is still controversy in the etiology and pathogenesis of cerebral watershed infarction (CWI). The classification of watershed infarction is also confusing. Great changes have taken place in the knowledge of CWI with the development of the medical and imaging technology. Based on the concept of the perforating artery-neural tissue units, the innovative speculation on the relation among leukoaraiosis (LA) (belong to white matter lesions), CWI and the mechanism of the perforating artery infarction formation was proposed in this paper. Based on the combination possibility of different perforating artery-neural tissue units, the CWI was classified as lateral watershed infarction (anterior cortical and posterior cortical watershed infarction), internal watershed infarction (anterior and interior type, posterior and interior type and interior type) and deep watershed infarction (deep anterior type, deep posterior type and the various subtypes). This paper suggests that LA might be caused by chronic watershed cerebral ischemia change, and perforating artery infarction and CWI are the same strain. This inference may help us to understand the relation among the mechanisms of the perforating artery infarction, CWI and LA.

Internal borderzone infarction following acute middle cerebral artery occlusion

In 36 patients suffering acute middle cerebral artery (MCA) occlusion, we studied the angiographic findings within 6 hours of the ictus and the chronic CT results at 3 months. Seven patients suffering distal pial MCA branch occlusion developed a pattern of internal borderzone infarction on follow-up CT. Carotid artery or carotid siphon stenosis or occlusion was absent in all seven. Proximal MCA branch occlusions, prior to the origin of the lenticulostriate arteries, were associated with extensive cortical and deep infarction in the entire MCA territory in 14 patients. There was proximal carotid artery or siphon stenosis or occlusion in 12 of these 14 patients. The remaining 15 patients showed a mixture of proximal and distal MCA occlusions and patchy ischemic damage in the MCA territory. There were no cases of superficial cortical watershed infarction. These data show that internal borderzone infarctions may result from intracranial MCA branch occlusions alone and need not be associated with hemodynamic alterations due to large vessel extracranial disease.

The variable clinical and CT findings after carotid occlusion: the role of collateral blood supply.

A retrospective review of 61 cases of angiographically confirmed occlusion of one or both carotid arteries was carried out to look at the evidence that the presence of collateral blood supply influenced the extent and type of cerebral infarction. Forty six patients had bilateral angiography from which it was possible to assess collateral filling of the internal carotid and middle cerebral arteries. As expected, patients with no CT scan evidence of infarction more frequently had transient ischaemic attacks or retinal infarcts than did those with visible cerebral infarcts. Patients with small cortical ischaemic lesions usually had appropriate neuropsychological or neurological deficits. Three patients with cortical watershed infarcts had a fluctuating deficit. Of the patients with bilateral angiograms 67% showed some filling via collaterals of the middle cerebral artery, and 43% of the internal carotid artery in the siphon. Those with collateral filling were mostly found to have normal CT scans or evidence of peripheral cortical lesions. By contrast most watershed and full territory infarcts were found in individuals whose angiograms showed no collateral filling. It is suggested that in many cases infarction occurs despite collateral flow and is due to distal embolism and that this may be relevant to the recently reported failure of the EC/IC bypass operation.