Video Atlas of Acute Ischemic Stroke Intervention (eBook)
212 Seiten
Georg Thieme Verlag KG
978-1-63853-705-2 (ISBN)
1 Clinical and Imaging Evaluation
General Description
An abundance of medical information has been written about the various clinical and imaging methodologies for the evaluation of a patient for endovascular thrombectomy (ET). This chapter represents a more pragmatic approach to the evaluation of acute ischemic stroke (AIS) in a patient with a suspected large vessel occlusion (LVO). Here, we discuss how to recognize and confirm the presence of LVO based on the clinical presentation and review the minimal imaging criteria necessary to decide whether to bring the patient to the angiography suite for ET.
Keywords: ASPECTS, large vessel occlusion, NIHSS, perfusion
1.1 Clinical Evaluation
●Prehospital stroke screening tools essentially serve two tasks: (1) to distinguish stroke from stroke-like mimics (such as encephalopathy or hypoglycemia) and (2) to identify stroke patients with a high probability of having an LVO. These tools are most relevant in the prehospital setting when emergency medical personnel determine the most appropriate type of stroke center for the triage of a patient with a suspected stroke.
●The Face Arm Speech Test (FAST) and Cincinnati Prehospital Stroke Scale (CPSS) are examples of stroke screen tools that incorporate facial palsy, motor arm, and dysarthria. The Los Angeles Motor Scale (LAMS) and the Rapid Arterial oCclusion Evaluation (RACE) are examples of LVO detection scales.
●The National Institute of Health Stroke Scale (NIHSS) is the AIS severity score that is most relevant to the in-hospital setting (Table 1.1). This is a uniform language that allows medical providers to accurately gauge stroke severity, communicate with each other, and make treatment decisions. Diligent documentation of baseline NIHSS score allows timely recognition of early neurological deterioration, alerting the neurointerventionist of possible complications such as reperfusion hemorrhage or reocclusion.
●Most patients with AIS from LVO eligible for ET will have an NIHSS score within the 10 to 25 range. Patients with “mild” symptoms defined as NIHSS score < 6 may harbor an LVO or a more distal medium vessel occlusion (MeVO); the decision to proceed with ET in such patients requires a more thorough consideration of the associated risks and benefits.
Table 1.1 The National Institutes of Health Stroke Scale (NIHSS)
| Category | Score description |
| Level of consciousness (LOC) | 0—alert 1—easily arousable by minor stimulation 2—not alert, requires repeated stimulation 3—unresponsive/flaccid |
| LOC Questions | 0—answers both questions correctly 1—one question correctly 2—answers neither question correctly |
| LOC One-step commands | 0—performs both tasks correctly 1—performs one command correctly 2—performs neither command correctly |
| Gaze | 0—normal gaze 1—partial gaze palsy 2—forced deviation or total palsy |
| Vision | 0—no visual loss 1—partial hemianopia 2—complete hemianopia 3—bilateral hemianopia or cortical blindness |
| Face | 0—normal 1—minor paralysis 2—partial paralysis (lower face) 3—complete paralysis (of one or both side) |
| Motor arm | 0—no drift 1—drift 2—some effort against gravity 3—no effort against gravity 4—no movement |
| Motor leg | 0—no drift 1—drift 2—some effort against gravity 3—no effort against gravity 4—no movement |
| Limb ataxia | 0—absent 1—present in one limb 2—present in two limbs |
| Sensory | 0—normal 1—mild or moderate sensory loss 2—severe or total sensory loss |
| Language | 0—normal 1—mild or moderate aphasia 2—severe aphasia 3—global aphasia or patient is mute |
| Dysarthria | 0—normal 1—mild or moderate dysarthria 2—severe dysarthria |
| Extinction and inattention | 0—normal 1—deficit in one modality 2—deficit in more than one modality or profound deficit |
Source: Adapted from https://stroke.nih.gov/resources/scale.htm
1.2 Imaging Evaluation
●Brain noncontrast computed tomography (NCCT) scan allows rapid differentiation between AIS and brain hemorrhage. This simple imaging modality is an ideal choice in many emergency departments (ED).
●Just like the NIHSS score allows team members to accurately communicate the degree of clinical stroke severity, the Alberta Stroke Program Early CT Score (ASPECTS) is a common imaging scoring system to describe the extent of early stroke on CT (Fig. 1.1).
●In many cases, NCCT combined with computed tomography angiography (CTA) to detect the location and extent of LVO will provide the minimum information needed to determine if ET is indicated (Fig. 1.2).
●Additional imaging modalities, such as brain perfusion (mainly in the form of computed tomography perfusion [CTP]) or magnetic resonance imaging (MRI), are often not necessary (Fig. 1.2 and Fig. 1.3). ET is capable of greatly reducing disability and mortality in a wide range of patients including those with various degrees of baseline stroke burden and LVO location, all of which can be reliably assessed with CT and CTA alone. Of course, unique clinical scenarios exist when additional imaging is needed (Fig. 1.4).
Fig. 1.1 Alberta Stroke Program Early CT Score (ASPECTS). Noncontrast computed tomography (NCCT), axial view. (a) Ganglionic and (b) supraganglionic levels. The scan is assigned a score ranging from 0 to 10 using 10 standard regions representing distinct middle cerebral artery (MCA) territories. A cumulative score is calculated based on the evidence (score of 0) or lack of (score of 1) early ischemic changes in each territory. C, caudate; IC, internal capsule; L, lentiform nucleus; I, insula; M1–3, ganglionic cortical regions; M4–6, supraganglionic cortical regions. Regions M4 and M5 contain early ischemic changes; thus, the total ASPECTS is 8. (c) Computed tomography angiography (CTA), three-dimensional (3D) reconstruction, demonstrating a left M1 occlusion. (d) Screen shot example of windowing and leveling used in this case. Here, Window 40/Level 40 is selected for the best visualization of early ischemic changes. Optimal stroke windows will depend on visual preferences and thus may be different. W: 35–40/L: 35–40 are commonly used.
Fig. 1.2 Noncontrast computed tomography (NCCT) and computed tomography angiography (CTA) for detecting middle carotid artery (MCA) occlusion. (a) NCCT, axial view (left image—supraganglionic level, right image—ganglionic level). Minimal early ischemic changes are present. Alberta Stroke Program Early CT Score (ASPECTS) is above 6. (b) CTA, coronal view, showing a filling defect at the right M1 bifurcation representing a fresh clot (arrow). This patient has an National Institutes of Health Stroke Scale (NIHSS) score of 16 (neglect, right gaze preference, and left hemiparesis). The imaging data obtained in (a) and (b) are sufficient to determine the eligibility of this patient for endovascular thrombectomy (ET). (c) NCCT, coronal view, showing a hyperdense MCA sign (arrow). With such a high NIHSS score, the decision to proceed with ET is even reasonable without obtaining CTA, which becomes relevant for cases in which CTA is not readily available. (d) Computed tomography perfusion (CTP), automated processing with RapidAI software (iSchemaView), depicting an M2 MCA territory region with abnormal perfusion (green—ischemic penumbra, magenta—ischemic core). Although this imaging pattern proves that the patient is eligible for ET, the same clinical decision to treat with ET can be reached without CTP. A more harmful clinical scenario would be to obtain CTP showing an “unfavorable” imaging profile and use this information to exclude the patient from ET all together. (e) Digital subtraction angiography (DSA), right internal carotid artery (ICA) injection, anteroposterior (AP) view, confirming a “saddle” embolus in the MCA bifurcation extending into both M2 branches (arrow).
Fig. 1.3 Example of M1 occlusion with poor Alberta Stroke Program Early CT Score (ASPECTS). (a) Noncontrast computed tomography (NCCT), axial view (left image—ganglionic level, right image—supraganglionic level). In this case of wake-up right internal carotid artery (ICA) occlusion, extensive ischemic changes of the entire middle carotid artery (MCA) territory are present. The ASPECTS is 1 (the caudate region is the only one without signs of ischemia). Endovascular thrombectomy (ET) in this case is futile. (b) Computed tomography perfusion (CTP), showing a large MCA territory region with abnormal perfusion (green—ischemic penumbra, magenta—ischemic core). In this case, the extent of the perfusion imaging core is underestimated as ischemic damage of M4–6 MCA regions is clearly seen on NCCT already.
Fig. 1.4 Example of...
| Erscheint lt. Verlag | 9.3.2022 |
|---|---|
| Sprache | englisch |
| Themenwelt | Medizinische Fachgebiete ► Chirurgie ► Herz- / Thorax- / Gefäßchirurgie |
| Medizinische Fachgebiete ► Chirurgie ► Neurochirurgie | |
| Medizin / Pharmazie ► Medizinische Fachgebiete ► Neurologie | |
| Schlagworte | catheter • clot • Device • Endovascular • Ischemia • Neurology • Occlusion • Thrombectomy |
| ISBN-10 | 1-63853-705-4 / 1638537054 |
| ISBN-13 | 978-1-63853-705-2 / 9781638537052 |
| Haben Sie eine Frage zum Produkt? |
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