Acute Middle Cerebral Artery Infarction Research Articles

Transcranial Sonographic Monitoring of Hemorrhagic Transformation in Patients With Acute Middle Cerebral Artery Infarction

ABSTRACTBackground and Purpose. Previous studies indicate the potential of transcranial sonography (TCS) to detect cerebrovascular disease. The authors conducted this patient study to evaluate the diagnostic potential of gray‐scale TCS in depicting hemorrhagic transformation (HT) in the early phase of middle cerebral artery infarction. Methods. TCS was performed in 32 patients with acute ischemic stroke in the middle cerebral artery territory less than 12, 24 ± 4, 72 ± 6, and 120 ± 12 hours after symptom onset (SONOS 5500, S4 probe, 16 cm investigation depth). Hemorrhagic transformation was identi f ied as hyperechogenicity in the MCA territory, and the echogenicity of these areas was assessed. In addition, the dislocation of the third ventricle (midline shift, MLS) was assessed by TCS. Size and localization of infarction were determined by cranial computed tomography (CCT). Results. In 10 of 11 patients, TCS detected HT as confirmed by CCT. In 1 patient, TCS provided a false‐positive result. In another patient, TCS was unable to detect the hemorrhage (sensitivity, 91%; specificity, 95%). The echointensity of HT increased over time. MLS measurement failed to predict fatal outcome in 1 patient. Conclusions. TCS is a promising tool for depicting HT in patients with acute hemispheric stroke and might be suitable for monitoring purposes.

Evaluation of Serum S100B as a Surrogate Marker for Long-term Outcome and Infarct Volume in Acute Middle Cerebral Artery Infarction

An easily accessible and valid surrogate marker for interventional stroke trials is needed. To investigate the usefulness of various S100B serum measures to predict long-term outcome and infarct volume in patients with acute stroke. Inception cohort study. Tertiary care university hospital. Thirty-nine patients (mean +/- SD age, 69.1 +/- 11.5 years) with acute nonlacunar middle cerebral artery infarction presenting less than 6 hours after symptom onset. Functional outcome 6 months after stroke (modified Rankin scale score) and final infarct volume on day 7 by means of standardized volumetry of brain images. Serum S100B level was determined at hospital admission and 24, 48, 72, 96, 120, and 144 hours after symptom onset. Single S100B measures obtained 48 and 72 hours after stroke onset demonstrated the highest Spearman rank correlations with modified Rankin scale scores (rho = 0.68 and rho = 0.67, respectively; P<.001) and infarct volume (rho = 0.95 and rho = 0.94, respectively; P<.001). A 48-hour S100B value of 0.37 microg/L or less revealed a sensitivity of 0.87 and a specificity of 0.78 in predicting an independent functional outcome. In a multivariate model, S100B emerged as an outcome predictor that was independent of age, sex, stroke severity, etiology, lesion side, and risk factors. Single S100B values obtained 48 and 72 hours after stroke onset provide the highest predictive values with respect to functional outcome and infarct volume in nonlacunar middle cerebral artery infarction. More complex measures of the S100B kinetic (ie, area under the curve or peak value) were not superior. Therefore, these single S100B measures appear to be useful surrogate end points in acute interventional stroke trials.

Early computed tomography features in extensive middle cerebral artery territory infarct: prediction of survival

Background: To assess the predictive value of prognosis of different computed tomography (CT) features and National Institutes of Health Stroke Scale score (NIHSS) in acute extensive middle cerebral artery (MCA)...

Perfusion harmonic imaging in acute middle cerebral artery infarction

Initial reports indicate that cerebral perfusion deficits in acute ischemic stroke might be detectable by means of transcranial harmonic imaging after an ultrasound contrast agent (UCA) bolus injection. Twenty-four patients with acute middle cerebral artery (MCA) infarction were investigated twice with perfusion harmonic imaging (PHI) after Levovist (Schering, Berlin, Germany) bolus injection no longer than 12 h after symptom onset. The findings were compared with those of cranial computed tomography (CCT). All 24 patients suffered from acute ischemic stroke of the MCA territory (median National Institutes of Health Stroke Scale score: 15 points). Corresponding to the area of infarction in follow-up CCT, a marked contrast deficit was visualized in 19 of 24 patients by initial PHI, which had a sensitivity and specificity of 86.4% and 96.2%, respectively, for predicting the occurrence and localization of a definite infarction in the midthalamic plane. The area of hypoperfusion in the initial PHI investigation correlated with the definite area of infarction in follow-up CCT (r = 0.66, p < 0.01). When time-intensity curves of both hemispheres were compared, the areas under the curve were significantly less in the symptomatic brain regions (p = 0.01). With PHI and UCA bolus injection, it is possible to assess cerebral perfusion deficits that correlate with the definite area of infarction in acute ischemic stroke patients. (E-mail: seidel_g@neuro.mu-luebeck.de)

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Harmonic Imaging in Acute Stroke: Detection of a Cerebral Perfusion Deficit With Ultrasound and Perfusion MRI

Perfusion harmonic imaging of the brain is a new ultrasound technique for assessing cerebral perfusion. In a patient with acute middle cerebral artery infarction, this method detected a cerebral perfusion deficit corresponding to the area of delayed perfusion as displayed by perfusion magnetic resonance imaging.

Mannitol bolus preferentially shrinks non-infarcted brain in patients with ischemic stroke.

Changes in brain tissue volume in six patients who had acute complete middle cerebral artery (MCA) infarctions and CT evidence of midline shift were measured using the brain boundary shift integral (BBSI) on sequential T1-weighted MR images acquired before and after a 1.5-g/kg bolus infusion of mannitol. At 50 to 55 minutes after the baseline scan, total brain volume decreased by 8.1 +/- 2.8 mL (0.6%, p < 0.005). Brain in the noninfarcted hemisphere shrank more (0.8 +/- 0.4%) than in the infarcted hemisphere (0.0 +/- 0.5%, p < 0.05).

Treatment options for large hemispheric stroke.

Some stroke patients suffering acute middle cerebral artery (MCA) infarction develop massive brain edema and herniation, a condition known as malignant MCA infarction. Severe swelling increases intracranial pressure (ICP) and leads to progressive brainstem dysfunction. Once ICP reaches critical values (>30 mm Hg) herniation occurs, usually within 2 to 5 days. Patients rarely survive (80% mortality) with standard treatment, and those who do are often severely disabled. Malignant MCA infarction is often missed by neurologists, despite well-defined clinical and neuroimaging (CT scan) diagnostic criteria. After diagnosis, conventional treatments such as osmotherapy, barbiturates, buffers, and hyperventilation center on reducing ICP. The goal of hyperosmolar therapy is to increase the serum osmolarity to approximately 315-320 mOsm/L. Enteric glycerol is used routinely to reduce ICP. In more severe cases and when glycerol fails, mannitol may be administered. Other therapies are also available, including hypertonic saline solution, THAM (Tris-hydroxy-methyl-aminomethane) buffer, and high-dose barbiturates. Hyperventilation also helps reduce ICP. All measures work effectively for a short time only. Other approaches to control elevated ICP, including decompression surgery and hypothermia, have shown promising results. In the Heidelberg decompression surgery trial, mortality in surgically treated patients was significantly lower (32%) than in non-treated patients (76%) despite conventional treatment. Importantly, of the surviving treated patients, 66% were rated independent with only mild to moderate disability. Moderate hypothermia (33-36 degrees C) has recently been shown to be effective in severe MCA infarction. Hypothermia induction within 14 hours of ischemic injury and maintained for 72 hours significantly reduced ICP and mortality (44%).

The prognostic value of cortical magnetic stimulation in acute middle cerebral artery infarction compared to other parameters

The prognostic value of magnetic evoked potentials (MEP), somatosensory evoked potentials (SSEP), age and radiological parameters was determined in 50 patients with acute middle cerebral artery infarction. We performed MEP and SSEP within 4 days and after 6 weeks and 3 months of the infarction and assessed clinical improvement by using the Barthel index (BI) and the Rankin scale. The localization and extent of the infarction was investigated by CT scanning or NMR. All parameters were correlated to clinical outcome and the prognostic significance of each parameter in addition to BI was determined. MEP, SSEP, and age were valuable prognostic parameters in predicting stroke outcome when used together with the BI. However, in stepwise regression analysis using all parameters simultaneously, only MEP and age significantly contributed to clinical outcome in addition to BI. Patients showed a better outcome when their MEP was normal or delayed, measured within 4 days of the infarction, compared to patients with absent MEP. Clinical outcome was better at a younger age.

Early CT signs in acute middle cerebral artery infarction

During the first hours after acute ischemic stroke, the CT usually shows no abnormalities. Therapeutic trials of ischemia in the middle cerebral artery (MCA) territory involves decision-making when the CT may not show obvious ischemic changes. We reviewed 100 consecutive patients, admitted within 14 hours after a first stroke. Selective criteria were clinical presentation with MCA ischemia and at least two CTs (1 initial and 1 control). All CTs were retrospectively analyzed by at least two physicians blinded to the patient's status. On the first CT, early signs were hyperdense MCA sign (HMCAS), early parenchymatous signs (attenuation of the lentiform nucleus [ALN], loss of the insular ribbon [LIR], and hemispheric sulcus effacement [HSE]), midline shift, and early infarction. Subsequent infarct locations were classified according to total, partial superficial (superior or inferior), deep, or multiple MCA territories. Clinical features, etiology, and Rankin scale were collected. There were 52 women (mean age 70.8). The CTs were performed at mean 6.4 hours (1 to 14 hours) and before the sixth hour in 62% of the patients. Early CT was abnormal in 94% of the cases, and the abnormalities found were an HMCAS in 22 patients, ALN in 48, LIR in 59, HSE in 69, midline shift in 5, and early infarct in 7. CT was normal in six patients where it was performed earliest (mean 4.5 hours) and in the oldest patients (mean age 80.1). Early parenchymatous CT signs were significantly associated with subsequent MCA infarct location and extension: ALN and deep infarct, HSE and superficial infarct, LIR and large infarct. HMCAS was never found in isolation and was always associated with the three other signs in extended MCA infarct. The presence of two or three signs (ALN, LIR, or HSE) was associated with extended MCA infarct (p < 0.001) and poor outcome (p < 0.001). Our findings suggest that CT frequently discloses parenchymal abnormalities during the first hours of ischemic stroke. Early signs allow the prediction of subsequent infarct locations; CT may provide a simple tool in evaluating the early prognosis of MCA infarction and thus may be useful in selecting better treatments.

Continuous ischemic damage after acute middle cerebral artery infarctions in humans demonstrated by short-echo proton spectroscopy

Continuous ischemic damage after acute middle cerebral artery infarctions in humans demonstrated by short-echo proton spectroscopy

Continuing Ischemic Damage After Acute Middle Cerebral Artery Infarction in Humans Demonstrated by Short-Echo Proton Spectroscopy

Proton MR spectroscopy is a noninvasive method of monitoring in vivo metabolite concentration changes over time. The aim of this work was to study the ischemic penumbra in humans by measuring the metabolic changes that occur after a middle cerebral artery territory infarction. Diagnostic MRI and short-echo time MR spectroscopy were performed on a 1.5-T system. Localized proton MR spectroscopy was performed within the area of cerebral infarction and in a homologous area of the contralateral hemisphere. The residual water resonance in the spectra was removed with the use of the Hankel Lanczos singular value decomposition method, after which peak area estimates were obtained by means of the variable projection time domain fitting analysis. The unsuppressed water signal was used as an internal concentration standard. Ten patients with acute middle cerebral artery infarction were studied within 28 hours of stroke onset and followed up for a period of up to 3 months. Significant changes were seen in the initial spectra from the infarct compared with the contralateral spectra. Lactate, a marker of anaerobic metabolism, was present within the infarct but not detected in the contralateral hemisphere. N-Acetyl aspartate, a neuronal marker, and total creatine were significantly reduced. The initial choline signal, arising from choline-containing compounds within the cell and cell membrane, remained unchanged in the infarct core compared with the contralateral hemisphere. Further reductions in N-acetyl aspartate and total creatine concentrations occurred within the first week. A fall in the lactate concentration was seen within the infarct core during the first 7 to 10 days. Similar reductions in the choline concentration were observed during this period. The demonstration of the continuing loss of cerebral metabolites within an infarct region suggests that further cell loss occurs up to 10 days after infarction. The continuing loss of neurons may represent continued ischemic damage after middle cerebral artery infarction.

Loss of the insular ribbon: another early CT sign of acute middle cerebral artery infarction.

Although computed tomography (CT) remains the most frequently used imaging examination in acute cerebral infarction, its sensitivity for early detection of strokes remains limited. In middle cerebral artery (MCA) strokes less than 6 hours old, loss of definition of the gray-white interface in the lateral margins of the insula ("insular ribbon") was observed. The acute and subacute CT findings in 11 retrospective and 16 prospective patients are presented. Loss of the insular ribbon was detected in 12 of the prospective cases and in all 11 retrospective cases. The insular ribbon is supplied by the insular segment of the MCA and its claustral branches. With cessation of MCA flow, the insular ribbon becomes the region most distal from the anterior and posterior cerebral collateral circulations. Consequently, the insular ribbon effectively becomes a watershed arterial zone. Loss of the insular ribbon is thus a reflection of acute edema due to infarction. Loss of the insular ribbon appears to be another frequent and reliable finding in acute MCA stroke.

Cheyne-Stokes Respiration in the Patient with Acute Left Middle Cerebral Artery Infarction

Cheyne-Stokes Respiration in the Patient with Acute Left Middle Cerebral Artery Infarction