First ex vivo validation of a radioguided surgery technique with ß-radiation.

PURPOSE: A radio-guided surgery technique with ß(-)-emitting radio-tracers was suggested to overcome the effect of the large penetration of γ radiation. The feasibility studies in the case of brain tumors and abdominal neuro-endocrine tumors were based on simulations starting from PET images with several underlying assumptions. This paper reports, as proof-of-principle of this technique, an ex vivo test on a meningioma patient. This test allowed to validate the whole chain, from the evaluation of the SUV of the tumor, to the assumptions on the bio-distribution and the signal detection. METHODS: A patient affected by meningioma was administered 300MBq of (90)Y-DOTATOC. Several samples extracted from the meningioma and the nearby Dura Mater were analyzed with a ß(-) probe designed specifically for this radio-guided surgery technique. The observed signals were compared both with the evaluation from the histology and with the Monte Carlo simulation. RESULTS: we obtained a large signal on the bulk tumor (105cps) and a significant signal on residuals of ∼0.2ml (28cps). We also show that simulations predict correctly the observed yields and this allows us to estimate that the healthy tissues would return negligible signals (≈1cps). This test also demonstrated that the exposure of the medical staff is negligible and that among the biological wastes only urine has a significant activity. CONCLUSIONS: This proof-of-principle test on a patient assessed that the technique is feasible with negligible background to medical personnel and confirmed that the expectations obtained with Monte Carlo simulations starting from diagnostic PET images are correct.

Overview: hyperacute rt-PA stroke treatment. The NINDS rt-PA Stroke Study Group.

Ischemic stroke remains a significant problem in the United States. Complex intracellular metabolic events occur leading to cell death. A search for treatments to prevent this ischemic process continues. Thrombolytic agents, recently developed and tested, may lessen the disabling effects of stroke.

Pathophysiology and mechanisms of acute ischemic stroke. The NINDS rt-PA Stroke Study Group.

Stroke is a leading cause of death and disability among Americans. The recent US Food and Drug Administration approval of recombinant tissue plasminogen activator (rt-PA, Activase) for the treatment of acute ischemic stroke offers the first proven therapy to reverse or ameliorate stroke symptoms. rt-PA is thought to restore circulation in the patient with acute ischemic stroke by dissolving an occluding thrombus or embolus. A basic understanding of cerebral circulation and the mechanism by which stroke compromises brain tissue is fundamental to appreciating this new therapy. The importance of prompt stroke diagnosis and treatment cannot be underestimated.

Code Stroke: rapid transport, triage and treatment using rt-PA therapy. The NINDS rt-PA Stroke Study Group.

With the approval of rt-PA therapy for ischemic stroke, stroke care has acutely transitioned from focusing on rehabilitative services to emergency services. This treatment, which must be initiated within the first three hours after the onset of stroke symptoms, requires reorganization of current management approaches. Developing a Code Stroke Team facilitates this process and helps to identify potential thrombolysis candidates. A pathway to deliver rapid care begins with 911 notification and transport, emergency department triage and procedures, and moves through the initiation of thrombolytic therapy. We call this pathway "Code Stroke".

Nursing care of acute stroke patients after receiving rt-PA therapy. The NINDS rt-PA Stroke Study Group.

Treatment with tissue plasminogen activator (rt-PA) for acute stroke requires intensive care of the patient. The risk of thrombolytic therapy and the need for rapid interventions make it clear that the nursing role during this time is crucial. Nurses should be familiar with safe dosage and administration of rt-PA for stroke, which is clearly different than administration of rt-PA for myocardial infarction. Furthermore, thrombolytic stroke treatment must be accompanied by intensive neurological monitoring to observe for complications. Intracerebral hemorrhage is usually accompanied by an acute change in neurological status and vital sign instability. Intensive monitoring of neurologic condition, vital signs, cardiac status and other standard critical care practices must be initiated immediately to optimize patient outcome.

Nursing management of acute complications following rt-PA in acute ischemic stroke. The NINDS rt-PA Stroke Study Group.

In the National Institutes of Neurologic Disorders and Stroke (NINDS) recombinant tissue plasminogen activator (rt-PA) stroke trial, the primary adverse events monitored were intracranial hemorrhage (ICH), systemic bleeding, death and new stroke. Nurses caring for the study patients noted these adverse events and other complications. In addition to what is known about acute ischemic stroke (AIS), the NINDS trial provides further information for optimal care of this specific group of patients. The complications found in this trial require expert nursing care to monitor, prevent and intervene, making clinical decisions relevant to the patients needs. The critical decision-making process must be grounded in knowledge of acute stroke physiology and thrombolysis.

Using the NIH Stroke Scale to assess stroke patients. The NINDS rt-PA Stroke Study Group.

The stroke patient is acutely ill within minutes of symptom onset. Typically, he or she is awake and thus requires a focal neurologic exam to evaluate vision, movement, sensation and language. With the advent of acute stroke treatments that need to be rapidly implemented, it is critical that the nurse be able to assess patients and relay the information accurately and efficiently to other members of the health care team. Performing and documenting the awake stroke exam in the most efficient and useful manner is key to the nursing care of the stroke patient. The National Institutes of Health Stroke Scale (NIHSS) is a systematic assessment tool designed to measure the neurologic deficits most often seen with acute stroke patients. Originally designed as a research tool, it is a nonlinear ordinal scale, with possible scores ranging form 0-42. Exam performance has been timed to take 5-8 minutes. Use of the NIHSS includes documentation of neurologic status and outcome, data collection for planning safe nursing care and standardization of information exchanges between nurse caregivers and other health care professionals.

Education to improve stroke awareness and emergent response. The NINDS rt-PA Stroke Study Group.

Patients delay in responding to stroke as an emergency in part because they have deficient information about the disease and treatment. Healthcare providers may also have a lack of information about stroke assessment and management, which could attribute to delays in patient care. In order to provide early, rapid stroke treatment in eligible persons, the public and the healthcare community must be informed. Information on stroke risk, symptoms and treatment should be provided to those likely to experience stroke, the general public and the emergency and medical communities who may witness and intervene when stroke occurs. Programs developed at the eight centers of the National Institute of Neurological Disorders and Stroke (NINDS) rt-PA stroke trial provide a sampling of approaches that increase awareness in these groups. Lessons learned include: 1. Program planning should start with a community needs assessment. 2. A variety of strategies can be applied to meet the community needs and resources. 3. Educational principles and models should be utilized in planning effective programs. 4. The message must be simple: "Stroke is an emergency. Time is brain".

Clinical-radiographic correlations within the first five hours of cerebral infarction.

Fifty patients, ages 54-79, with ischemic hemispheric strokes productive of hemiparesis, at a minimum, underwent standardized neurological evaluations, computed tomographic scanning and cerebral angiography (N = 38) or carotid ultrasound (N = 12) within 5 h of onset. A second scan was performed at 5-7 days. Clinical scores were not associated with a history of, or the presence of: hypertension, smoking or cardiac disease, including atrial fibrillation, nor with severe internal carotid artery stenosis or occlusion. Clinical scores were adversely affected by early scan abnormalities (especially mass effect), lesion size, intracranial arterial occlusions, elevated serum glucose levels and the subsequent development of hemorrhagic infarction. Glucose levels correlated with infarct size and the development of hemorrhagic infarction. Delayed intracranial arterial filling and collateral flow were associated with reduced infarct size but did not confer clinical protection. We believe that combining the initial glucose level and scan results has prognostic significance, and early angiography is valuable in characterizing infarct etiology and assessing clinical severity.

Computed tomographic-angiographic findings within the first five hours of cerebral infarction.

BACKGROUND AND PURPOSE: Modern management of acute stroke necessitates early diagnosis. To this end, we sought to delineate the radiographic features of focal hemispheric infarction within 5 hours of ictus. METHODS: Fifty patients, ages 54-79, with ischemic strokes productive of at least hemiparesis underwent computed tomographic scanning and cerebral angiography (n = 38) or carotid ultrasound (n = 12). Radiographic lesions were characterized for location, size, and pathophysiology. RESULTS: Acute abnormalities, hypodensity, and mass effect were seen in 56% of scans and confirmed on a second scan 5-7 days later. Intracranial angiographic abnormalities occurred in 61% of patients: arterial occlusions in 45% and delayed arterial filling in 16%. Hemorrhagic infarctions occurred in 26% of second scans and were associated with mass effect (100%) and arterial occlusions (89%). Infarcts with hemorrhagic transformation were larger on both scans than those without (p = 0.001). Of four patients with infarctions in watershed territories on the scans, two had middle cerebral artery occlusions on angiography, thereby questioning the specificity of such scan lesions to low-flow states. CONCLUSIONS: We conclude that cerebral infarctions are often visible on early scans, but their locations may not be etiologically determinative. The infarcts associated with intracranial arterial occlusions (45%) were of thromboembolic origin, but, given current controversies as to the pathophysiology of lacunar and watershed infarctions, we cannot ascertain the etiology in the remainder. These findings are relevant to the new stroke therapies that require administration in the first hours after infarction.