Neurosarcoidosis: Longitudinal experience in a single-center, academic healthcare system

OBJECTIVE

To characterize patients with neurosarcoidosis within the University of Utah healthcare system, including demographics, clinical characteristics, treatment, and long-term outcomes.

METHODS

We describe the clinical features and outcomes of patients with neurosarcoidosis within the University of Utah healthcare system (a large referral center for 10% of the continental United States by land mass). Patients were selected who met the following criteria: (1) at least one International Classification of Diseases Clinical Modification, 9th revision code 135 or International Classification of Diseases Clinical Modification, 10th revision code D86* (sarcoidosis) and (2) at least one outpatient visit with a University of Utah clinician in the Neurology Department within the University of Utah electronic health record.

RESULTS

We identified 56 patients meeting the study criteria. Thirty-five patients (63%) were women, and most patients (84%) were white. Twelve patients (22%) met the criteria for definite neurosarcoidosis, 36 patients (64%) were diagnosed with probable neurosarcoidosis, and 8 patients (14%) were diagnosed with possible neurosarcoidosis. A total of 8 medications were used for the treatment of neurosarcoidosis. Prednisone was the first-line treatment in 51 patients (91%). Infliximab was the most effective therapy, with 87% of patients remaining stable or improving on infliximab. Treatment response for methotrexate and azathioprine was mixed, and mycophenolate mofetil and rituximab were the least effective treatments in this cohort.

CONCLUSIONS

This is a comprehensive characterization of neurosarcoidosis within a single healthcare system at the University of Utah that reports long-term response to treatment and outcomes of patients with neurosarcoidosis. Our results suggest the use of infliximab as a first-line therapy for neurosarcoidosis.

Tissue Plasminogen Activator Prescription and Administration Errors within a Regional Stroke System

BACKGROUND

Intravenous (IV) tissue plasminogen activator (tPA) utilization in acute ischemic stroke (AIS) requires weight-based dosing and a standardized infusion rate. In our regional network, we have tried to minimize tPA dosing errors. We describe the frequency and types of tPA administration errors made in our comprehensive stroke center (CSC) and at community hospitals (CHs) prior to transfer.

METHODS

Using our stroke quality database, we extracted clinical and pharmacy information on all patients who received IV tPA from 2010-11 at the CSC or CH prior to transfer. All records were analyzed for the presence of inclusion/exclusion criteria deviations or tPA errors in prescription, reconstitution, dispensing, or administration, and for association with outcomes.

RESULTS

We identified 131 AIS cases treated with IV tPA: 51% female; mean age 68; 32% treated at the CSC, and 68% at CHs (including 26% by telestroke) from 22 CHs. tPA prescription and administration errors were present in 64% of all patients (41% CSC, 75% CH, P < .001), the most common being incorrect dosage for body weight (19% CSC, 55% CH, P < .001). Of the 27 overdoses, there were 3 deaths due to systemic hemorrhage or ICH. Nonetheless, outcomes (parenchymal hematoma, mortality, modified Rankin Scale score) did not differ between CSC and CH patients nor between those with and without errors.

CONCLUSION

Despite focus on minimization of tPA administration errors in AIS patients, such errors were very common in our regional stroke system. Although an association between tPA errors and stroke outcomes was not demonstrated, quality assurance mechanisms are still necessary to reduce potentially dangerous, avoidable errors.

Abstract T P332: Despite Differences in Device Design, Anticoagulation, and Duration of Use, Pulsatile- and Continuous-Flow Left Ventricular Assist Devices Share Similar Stroke Rates and Outcomes

Background: Stroke is the primary adverse outcome in Left Ventricular Assist Devices (LVADs), not well-described in current literature. We hypothesized that pulsatile-flow devices would have worse stroke rates and outcomes than continuous devices.

Methods: This is a single-center retrospective study of all adult LVADs from 1999-2013 at the University of Utah utilizing the internal LVAD and Stroke Center databases. Complete chart review included review of all relevant outside records with no case loss. Categorical variables were computed using a χ 2 test; ordinal variables via the Mann-Whitney U test.

Results: Among 52 pulsatile (47 patients) and 91 continuous (81 patients) devices, 17.3% of pulsatile and 18.7% of continuous devices had at least one stroke/TIA (p=0.84). Stroke subtypes and LVAD-specific outcomes did not vary by device. Stroke severity was higher at first stroke/TIA with a median (IQR) NIHSS of 4 (2, 11) vs. 1 (1, 2) in continuous vs. pulsatile devices (p=0.03). Despite continuous devices having nearly twice the number of overall days on device (DOD), there was no difference in median DOD until first stroke/TIA: 170 in pulsatile; 165 in continuous; p=0.56. Stroke outcomes by device were good with mRS≤2 in 71% of pulsatile and 53% of continuous devices (p=0.42). All-cause 1-year mortality was high but with only the minority due to stroke (Table 1). Neither sepsis nor pump thrombus were associated with stroke/TIA.

Conclusions: Continuous devices provide longer DOD without increased stroke risk or significantly worse outcomes. First AIS/TIA events were more severe in continuous devices, with non-significantly worse mRS scores. In this study, we did not replicate previous findings of infection predisposing to stroke.

Neurology Academic Advisory Committee: a strategy for faculty retention and advancement

Major effort and expense are devoted to faculty recruitment. Subsequent direction, support, and guidance of faculty members for retention and academic advancement are often inconsistent and ineffective. Individual mentorship is widely endorsed as an important element in advancement but often does not occur or is uneven in its pragmatic benefit. We formed a Departmental Academic Advisory Committee to provide individualized advice and guidance about career development and institutional promotion, retention, and tenure procedures. To assess the effectiveness of this process, a survey was sent to faculty members. A 100% response rate was achieved. The results of the survey demonstrated high levels of acceptance by faculty members and described benefits experienced by faculty, including better understanding of promotion and tenure policies and specific actions taken to achieve professional goals. An academic advisory committee can be a valuable adjunct to individual mentorship and to meetings with department chairs to enhance faculty satisfaction and advancement of neurology faculty members.

Basilar artery occlusive disease in the New England Medical Center Posterior Circulation Registry

BACKGROUND

Most reports on basilar artery (BA) occlusive disease have retrospectively described single cases or small patient series.

OBJECTIVE

To assess clinical and vascular features, stroke mechanisms, etiologies, and outcome of moderate to severe BA occlusive disease among 407 patients in the New England Medical Center Posterior Circulation Registry, the largest prospective series of consecutively collected patients with posterior circulation ischemia to date.

RESULTS

We studied 87 patients and identified 3 patient groups with distinct vascular, clinical, etiological, and prognostic characteristics: isolated BA disease (39 patients [44.8%]), BA involvement as part of widespread posterior circulation atherosclerosis (36 patients [41.4%]), and embolism to the BA (12 patients [13.8%]). Vascular risk factors were common and often multiple. Most patients (54 [62.1%]) had involvement of the midportion of the BA. Fifty-eight patients (66%) initially had transient ischemic attacks, of whom 34 (58.6%) progressed to stroke. Transient ischemic attacks were usually multiple, lasted for several months, and increased in frequency as the stroke approached. When an infarct was present, the middle posterior intracranial territory was most often involved (66 patients [75.9%]). Outcome was much better than previously assumed. The mortality rate was 2.3%, and 62 patients (almost 75%) had minor or no deficits at follow-up. Outcome was best among patients with widespread atherosclerotic disease and worst in 7; (58.3%, with major disability) of 12 patients with embolism to the BA. Distal territory involvement, embolism, BA occlusion, decreased level of consciousness, tetraparesis, and abnormal pupils were significant predictors of poor outcome.

CONCLUSION

Inclusion of patients into 1 of the BA groups and early identification of predictive outcome factors guide diagnostic evaluation and treatment.

Silent infarction as a risk factor for overt stroke in children with sickle cell anemia: a report from the Cooperative Study of Sickle Cell Disease

OBJECTIVE

To determine whether children with homozygous sickle cell anemia (SCD) who have silent infarcts on magnetic resonance imaging (MRI) of the brain are at increased risk for overt stroke.

METHODS

We selected patients with homozygous SCD who (1) enrolled in the Cooperative Study of Sickle Cell Disease (CSSCD) before age 6 months, (2) had at least 1 study-mandated brain MRI at age 6 years or older, and (3) had no overt stroke before a first MRI. MRI results and clinical and laboratory parameters were tested as predictors of stroke.

RESULTS

Among 248 eligible patients, mean age at first MRI was 8.3 +/- 1.9 years, and mean follow-up after baseline MRI was 5.2 +/- 2.2 years. Five (8.1%) of 62 patients with silent infarct had strokes compared with 1 (0.5%) of 186 patients without prior silent infarct; incidence per 100 patient-years of follow-up was increased 14-fold (1.45 per 100 patient-years vs 0.11 per 100 patient-years, P =.006). Of several clinical and laboratory parameters examined, silent infarct was the strongest independent predictor of stroke (hazard ratio = 7.2, P =.027).

CONCLUSIONS

Silent infarct identified at age 6 years or older is associated with increased stroke risk.

Proximal extracranial vertebral artery disease in the New England Medical Center Posterior Circulation Registry

OBJECTIVE

To describe the clinical features of patients with occlusive disease of the proximal (V1) segment of the vertebral artery.

DESIGN AND PATIENTS

Patients with either occlusion or high-grade stenosis involving the V1 segment were chosen for study from the New England Medical Center Posterior Circulation Registry. The registry is a consecutive series of patients with signs and symptoms of posterior circulation ischemia seen at the New England Medical Center, Boston, Mass, during a 10-year period. Clinical features, radiographic findings, and patient outcome were reviewed.

RESULTS

Of the 407 patients in the registry, 80 (20%) had V1 segment lesions. Patients could be classified into 5 groups: (1) V1 disease and coexistent severe intracranial occlusive disease of the posterior circulation (n=22); (2) V1 disease with evidence of artery-to-artery embolism (n=19); (3) suspected V1 disease with artery-to-artery embolism, but with other potential causes of stroke or less certain vascular diagnosis (n=20); (4) V1 disease associated with hemodynamic transient ischemic attacks (n=13); and (5) proximal vertebral arterial dissection (n=6). Hypertension, cigarette smoking, and coronary artery disease were common risk factors. Clinical features, location of infarct, and outcome differed between groups and reflected the presumed mechanisms of stroke.

CONCLUSIONS

Occlusive disease involving the V1 segment of the vertebral artery is common in patients with posterior circulation ischemia, but is often associated with other potential mechanisms of stroke. However, in a series of patients seen at a tertiary referral center, occlusive disease of the V1 segment was the primary mechanism of ischemia in 9% of patients.

Intracranial vertebral artery disease in the New England Medical Center Posterior Circulation Registry

We studied 75 patients with severe intracranial vertebral artery (ICVA) occlusive disease from the New England Medical Center Posterior Circulation Registry to learn the etiologies and locations of the vascular lesions, the location and patterns of related ischemia and infarctions, and the outcomes. All patients had neuroimaging and vascular studies. Thirty-nine percent of patients had bilateral ICVA lesions. Twenty-four percent also had basilar artery disease and 36% had associated extracranial disease. The most common site of lesions was the distal ICVA after the origin of the posterior inferior cerebellar artery (PICA). Twenty-five percent of patients had only proximal intracranial posterior circulation territory infarcts (medullary and PICA cerebellar); 32% had infarcts that involved other intracranial territories in addition to the proximal territory. We found more distal intracranial territory infarcts resulting mainly from embolism from ICVA lesions than reported previously; this occurred in 17% of all patients. The ICVA was a recipient site for emboli in 8% of patients. Thirteen percent of patients died during follow-up. The outcome was favorable in most surviving patients. Three-fourths of them had no deficit or only slight disability. The patients with distal territory infarcts due to emboli from the ICVA had the worst outcome.

Proximal intracranial territory posterior circulation infarcts in the New England Medical Center Posterior Circulation Registry

We studied 91 patients with proximal intracranial territory posterior circulation ischemia from the New England Medical Center Posterior Circulation Registry to learn their distribution, underlying cardiovascular causes and longterm outcome. All patients had imaging and vascular studies. Six patients had proximal territory TIAs. Among 85 stroke patients, 52% had infarcts limited to the proximal territory, while 48% also had infarcts in other intracranial posterior circulation territories. Eighty-five percent of proximal territory infarcts were posterior inferior cerebellar artery (PICA) territory cerebellar infarcts and 30% were lateral medullary infarcts. One patient had a hemimedullary syndrome. Six patients had PICA territory cerebellar and lateral medullary infarcts. The most common vascular lesion in lateral medullary infarct patients was ipsilateral intracranial vertebral artery (ICVA) disease (38% isolated ICVA disease) and in PICA territory cerebellar infarcts, extracranial vertebral artery (ECVA) disease (29% isolated ECVA disease). Half of all lateral medullary infarcts were due to a hemodynamic mechanism, most often in situ thrombosis of an ICVA occlusive lesion. Half of all PICA territory cerebellar infarcts were due to intra-arterial embolism and one-fifth to cardiac origin embolism. Embolism was a more frequent cause of proximal territory posterior circulation infarcts than intrinsic ICVA disease. The etiological profiles of lateral medullary and PICA cerebellar infarcts were different. Seventeen percent of all patients died during follow-up (41 months) but mortality related to the acute stroke or new strokes was only 6 percent. The outcome was favorable in the surviving patients; 89% had no or only slight disability.

Cerebellar hemorrhagic infarction

We investigated 17 patients with 26 cerebellar hemorrhagic infarcts for their vascular anatomy, stroke mechanisms, and clinical course. Sixteen infarcts involved the superior cerebellar artery, nine the posterior inferior cerebellar artery, and one the anterior inferior cerebellar artery territories. The infarcts involved the full territory of the supplying arteries in 19 of 26 infarcts (73%). Sixteen of 17 patients were stable or improving when the hemorrhagic infarction was detected. All but one patient had an imaging study at the time of presentation that was negative for blood; hemorrhagic infarction was detected on routine serial scans performed during the first 15 days. Nine of the 17 patients were on anticoagulants when the cerebellar hemorrhagic infarct was detected; anticoagulation was maintained in eight of them with no clinical worsening. The stroke mechanism in all patients was considered embolic from cardiac and intra-arterial sources. The causes, imaging findings, and consequences of hemorrhagic infarcts in the posterior circulation are similar to those in the anterior circulation.

Stroke with sensory symptoms mimicking myocardial ischemia

OBJECTIVE

To report five stroke patients with sensory deficits including prominent chest discomfort mimicking angina.

BACKGROUND

Chest wall sensory discomfort, as a part of unilateral sensory dysfunction, has seldom been recognized as a potential imitator of cardiac ischemia.

METHODS

A retrospective review of stroke patients with sensory symptoms from the New England Medical Center Stroke Registry.

RESULTS

As a part of an acute stroke that included unilateral sensory symptoms and signs, five patients had chest pain or discomfort, which prompted cardiac evaluation for potential coronary artery disease. In two patients, the primary presentation was chest discomfort. In the other three, chest discomfort was part of a more extensive stroke syndrome. The symptoms were described as "burning," "hot feeling," "flashes," "tightness," and "cold." In three patients, an MRI or CT scan showed an infarct in the thalamus, corona radiata, or lateral medulla. Cardiac evaluation was negative in all but one patient who had single vessel percutaneous transluminal coronary angioplasty without resolution of sensory symptoms. Chest discomfort fluctuated but persisted for months or years after presentation.

CONCLUSION

Chest discomfort mimicking cardiac ischemia may be a prominent sensory symptom in acute stroke.

Brain edema after carotid surgery

The postoperative hyperperfusion syndrome describes an abrupt increase in blood flow with loss of autoregulation in surgically reperfused brain. Reports described a spectrum of findings, including severe headache, transient ischemia, seizures, and intracerebral hemorrhage. Hypertension is common after carotid artery surgery and often plays a role in the pathophysiology. We now report five patients with severe white matter edema after carotid surgery, a finding not previously included in the hyperperfusion syndrome. Five to 8 days after carotid surgery and after hospital discharge, each patient developed hypertension, headache, hemiparesis, seizures, and aphasia or neglect due to severe white matter edema ipsilateral to the carotid surgery. One patient had a small hemorrhage within the edematous area. Hypertension was severe in four patients and moderate in one. The carotid artery was patent by ultrasound or angiography in each patient after surgery. Transcranial Doppler showed increased velocities ipsilateral to surgery in two patients and bilaterally in one. Computed tomographic abnormalities and neurologic signs resolved within 3 weeks in four of the five patients treated with antihypertensives and anticonvulsants. The fifth patient died from herniation secondary to massive edema. Brain edema with focal neurologic signs should be included as a serious but potentially reversible component of the postoperative hyperperfusion syndrome.

Longitudinal monitoring of intracranial arterial stenoses with transcranial Doppler ultrasonography

The natural history of intracranial arterial stenoses remains relatively unknown. To monitor the progression of these lesions over time, the authors reviewed transcranial Doppler (TCD) laboratory reports at five hospitals for patients with angiographically documented intracranial arterial stenoses along the internal carotid artery distribution, and at least two TCD studies conducted more than 2 months apart. Twenty-two patients (19 men and 3 women; mean age, 64 years) with 29 stenoses were identified. The findings were compared to reproducibility data obtained from 11 age-matched control subjects with repeat TCD studies. During a mean follow-up period of 21 months, peak systolic flow velocities corresponding to the areas of stenosis increased in 9 arteries with lesions, and new collateral flow patterns, indicating further hemodynamic compromise distal to the lesions, developed in 2; one of the latter also had increased corresponding velocities. Thus, 10 (35%) arteries with lesions had TCD evidence of progression. Flow velocities remained the same in 13 (45%) stenotic vessels and dropped in 2 (7%). Findings were considered inconclusive for 4 lesions (14%). These findings suggest that intracranial arterial stenoses are dynamic lesions, and that they can evolve and cause further reductions of the arterial diameters after relatively short periods of time. TCD can noninvasively detect their hemodynamic effects.

Neurologic complications of infectious mononucleosis

A review of the neurologic complications of Epstein-Barr viral (EBV) infections is presented. EBV has been associated with a wide range of acute neurologic diseases in children. Encephalitis, meningitis, cranial nerve palsies, mononeuropathies, and many other neurologic ailments have been described since the confirmation of EBV as the etiology of infectious mononucleosis. It is important to recognize that EBV can cause a myriad of neurologic illnesses with or without the stigmata of infectious mononucleosis.

Transcranial Doppler validation pilot study

The use of transcranial Doppler sonography (TCD) for the evaluation of patients with ischemic cerebrovascular disease remains controversial. This study was organized to gather preliminary data regarding the sensitivity and specificity of TCD when compared to cerebral angiography in detecting stenosing lesions and collateral flow patterns of the anterior cerebral circulation. Forty-two patients from six medical centers were prospectively enrolled. Each received cerebral angiography and TCD testing within 24 hours of each other. Based on TCD criteria established a priori, the results were first analyzed by a blinded investigator and then by computer. Computerized analyses were then repeated with modified criteria. Collateral flow through the anterior communicating and ophthalmic arteries was detected with sensitivities of 62% and 100%, and specificities of 98% and 92%, respectively. Internal carotid artery proximal and distal severe ( greater than 70%) stenoses were detected with sensitivities of 79% and 100% and specificities of 88% and 97%. Middle and anterior cerebral artery stenoses and middle cerebral artery occlusion were detected with specificities exceeding 98%; however, the data were insufficient to determine sensitivity. Computerized analyses did not permit improvement of sensitivity and specificity of the baseline criteria. The selected TCD criteria are highly specific in detecting intracranial stenoses and collateral flow patterns of the anterior circulation. The criteria have limited but acceptable sensitivity and specificity in detecting internal carotid artery origin severe stenoses, and are highly sensitive in detecting ophthalmic artery retrograde flow. A study with a larger sample is necessary to provide definitive guidelines for diagnosis.

Postoperative brainstem and cerebellar infarcts

OBJECTIVE

To study the clinical features and causes of postoperative brainstem and cerebellar infarcts.

METHODS

Two groups were studied. The 10 group 1 patients had cardiac (eight) or aortic (two) surgery. The 12 group 2 patients had noncardiac-nonvascular surgery, including orthopedic (five), gynecologic (four), and general (three). Patients were studied by stroke services at university hospitals in Boston (13), Charlottesville (three), Baltimore (three), and Mainz (three) during 2 consecutive years.

RESULTS

Onset of strokes was immediately postoperative (six), during the first 48 postoperative hours (nine), and delayed 3 days or more (seven). Clinical syndromes were altered level of consciousness or cognition (15), vestibulocerebellar (four), and hemiparesis with focal brainstem signs (three). Infarction involved the brainstem (13), cerebellum (13), and posterior cerebral artery hemispheric territory (10). Causes: In group 1, five infarcts were due to cardiogenic embolism and three to embolism from the aorta. One patient had a postoperative pontine lacunar infarct and one developed an infarct in the territory of a known stenotic basilar artery. In group 2, one patient had vertebral artery injury from instrumentation, one had medical complications with severe hemorrhage and hypotension, and 10 most likely had position-related vertebral artery thromboses.

CONCLUSIONS

Patients with postoperative brainstem and cerebellar infarcts present with altered consciousness or vestibulocerebellar syndromes. The major cause of brain infarcts after cardiac surgery is embolism from the heart and aorta. The causes of infarction after general surgery are less clear, but neck positioning during or after surgery may play an important role by promoting thrombi in compressed arteries that later embolize intracranially when neck motion becomes free.

Anterior inferior cerebellar artery territory infarcts. Mechanisms and clinical features

Arterial lesions, mechanisms, territory, and clinical features of anterior inferior cerebellar artery (AICA) territory infarcts are only based on necropsy cases. To our knowledge, no large clinical series has been reported. We selected nine consecutive patients with AICA territory infarction confirmed by magnetic resonance imaging and angiography. Atherosclerosis was the only cause and all patients were hypertensive. Patients with pure AICA territory infarcts (n = 4) were diabetic and likely had basilar branch occlusion due to basilar artery plaques that extended into the AICA or microatheroma that blocked the AICA origin. These patients had no or had only recently had (1 day) prodromata. Patients with AICA plus infarct (n = 5) had basilar artery occlusion at the AICA and reconstitution of the distal basilar artery by collaterals through hemispheric anastomoses from the posterior inferior cerebellar arteries and posterior communicating arteries. All these patients except one had prodromata. In seven of nine patients, cranial nerve involvement indicated a lateral pontine lesion in the territory supplied by the AICA. Only two patients had the complete AICA syndrome, and none of the patients had isolated vertigo. The outcome was good in seven of nine patients. Isolated unilateral AICA infarcts should be regarded as most likely due to small artery atherosclerotic disease in diabetic patients. More widespread infarctions that include that AICA territory are due to basilar artery occlusive disease.

Intermittent downbeat nystagmus due to vertebral artery compression

Downbeat nystagmus (DBN) uncommonly occurs as a transient phenomenon, and it rarely occurs in patients with cerebrovascular disease. We observed a patient with intermittent DBN and lightheadedness due to transient obstruction of his dominant vertebral artery when he turned his head to his left side. Surgical removal of an osteophyte at the site of the angiographically demonstrated lesion relieved his symptoms.

Embolism from vertebral artery origin occlusive disease

We report 10 patients with severe occlusive disease of the vertebral artery (VA) origin in the neck with intra-arterial embolism to the posterior circulation. The VA lesions in seven patients were complete occlusions, and three patients had severe atherostenosis. All patients had strokes in the vertebrobasilar territory. The most frequent recipient sites of intra-arterial embolism were the intracranial VA-posterior inferior cerebellar artery region (8), and the distal basilar artery (BA) and its superior cerebellar and posterior cerebral artery branches (7). Two patients had pontine infarction due to BA embolism. The most common clinical signs were due to cerebellar infarction. Atherosclerotic disease of the VA origin has features in common with disease of the internal carotid artery origin. Both have similar risk factors and demography, and each can cause strokes by intracranial intra-arterial embolism.

Changing attentional demands in left hemispatial neglect

Seven variations of a letter cancellation test were used to examine how varying attentional demands affect hemispatial neglect in patients with right hemisphere lesions. While the 14 targets always remained in the same location, the number of distractors (zero, nine, 28, or 82) as well as their complexity (one letter or nine different letters) were varied. The percentage of targets canceled in the left hemispace was linearly related to the number of distractors. There were no differences between the complexity conditions. In a second study, the same 14 targets were presented but the distractors (zero, 14, or 41) were all placed on the right. Increasing the number of distractors on the right increased neglect on both sides of the space. Taken together, these results suggest that, while the limited attentional resources of the left hemisphere are biased toward the right hemispace, the absence of contralateral attentional demands allows these resources to be directed ipsilaterally.

Effects of changes in stimulus contingency on visual extinction

Left visual field (LVF) extinction during double simultaneous stimulation (DSS) is common in patients with right cerebral lesions. A postulate is that during DSS, the intact left hemisphere's limited attentional capacity is directed to right hemispace, resulting in LVF extinction. External cueing may help direct attention to the LVF and improve performance. In the present study, we varied patterns of unilateral stimulation preceding DSS in an attempt to redirect attention through expectancy. Nine patients (7 stroke, 2 tumor) with right hemisphere lesions each had 40 DSS trials with the distribution of unilateral stimulation trials systematically varied. Mean extinction percentages on DSS trials were 17% following 5 right unilateral trials, 30% following 1 right unilateral trial, 52% following 1 left unilateral trial, and 63% following 5 left unilateral trials. These findings indicate that the probability of extinction decreases following unilateral stimulation to the right visual field and increases following unilateral stimulation to the LVF. These results suggest that expectancy alters the attentional bias which mediates extinction.

Transcranial Doppler ultrasound: present status

Summary and critique. Advantages of method. TCD is a noninvasive test effective in monitoring blood velocities in large intracranial arteries. It uses small, potentially portable, relatively inexpensive equipment. The test can be repeated and therefore allows the detection of changes over time and after various physiologic studies or pharmacologie intervention, and during various postural and positional changes. TCD can also be used to monitor changes during surgery or other interventions.

Lateral thalamic infarcts

A patient with occlusion of the proximal posterior cerebral artery (PCA), a lateral thalamic infarct, and hemisensory loss later developed hemianopia and hemiparesis and had extensive PCA territory infarction in the midbrain, the lateral portion of the thalamus, and the occipital lobe noted at necropsy. Two other patients had lateral thalamic infarcts on computed tomography, normal angiographic findings, and presumed thalamogeniculate artery branch occlusion. There are three clinical syndromes associated with lateral thalamic infarction: (1) hemisensory loss, hemiataxia, and involuntary movements; (2) pure sensory stroke; and (3) sensory-motor stroke. Ataxia, adventitious movements, and sensory loss are due to infarction of the lateral, posterolateral, and posteromedial ventral nuclei caused by occlusion of the PCA proximal to the thalamogeniculate artery branches or by occlusion of large thalamogeniculate arteries. Pure sensory and sensory-motor strokes are due to smaller infarcts in the posterolateral-posteromedial ventral complex and adjacent internal capsule caused by occlusion of penetrating artery branches of the thalamogeniculate arteries.

Transcranial Doppler

TCD recording of flow velocities in intracranial vessels was first described by Aaslid in 1982. The utility of this instrument becomes more apparent as it is used in different clinical settings and compared with angiographic findings (Figures 1 and 2). Its importance in early detection of vasospasm in subarachnoid hemorrhage is now clearly known; increased flow velocity can be documented prior to neurologic deterioration and thus allow early institution of therapy. In patients with stroke or transient ischemic attack of unclear etiology, especially in blacks, Orientals, or females, who have a higher incidence of intracranial arterial disease, TCD can be a very important noninvasive means for detecting stenosis of intracranial vessels. Its value for assessing collateral circulation, intraoperative monitoring, and measuring CBF is quite promising. Hopefully, through further work with TCD, we will be able to clarify the spectrum of its usages as well as its limitations, though the preliminary data indicate that it should be an important addition to present noninvasive evaluations.

Dissection of the intracranial vertebral artery

We describe four patients and review prior reports to clarify the clinical, radiographic, and pathologic findings of intracranial vertebral artery (VA) dissection. A 43-year-old man and a 33-year-old woman had chronic bilateral VA dissecting aneurysms. The man had multiple episodes of subarachnoid hemorrhage (SAH) and necropsy showed multiple dissections and defects in the internal elastica. The woman had many brainstem TIAs and strokes during 3 years. Two other patients had SAH and unilateral dissections. Intracranial VA dissection causes four overlapping syndromes: (1) brainstem infarcts are usually due to subintimal dissection extending into the basilar artery, affect younger patients, and often are single fatal events; (2) SAH is due to subadventitial or transmural dissection; (3) aneurysms cause mass effect on the brainstem and lower cranial nerves; and (4) chronic dissections due to connective tissue defects cause extensive bilateral aneurysms and repeated TIAs, small strokes, and SAH.

Benign disappearance of ventricular thrombus after embolic stroke. A case report

The source for a patient's middle cerebral artery territory embolic stroke was found by echocardiography to be a left ventricular cardiac thrombus. The apical mass was large, pedunculated, and moved with systole into the ventricular cavity. The absence of ventricular dyskinesia was thought to favor a tumor, and surgery was considered before repeat echocardiography showed disappearance of the mass, making thrombus the likely diagnosis. No further embolic events occurred during or since the disappearance of the thrombus while on anticoagulation therapy. Serial echocardiography for change in or disappearance of a ventricular mass may be critical in distinguishing thrombus from tumor.

NMR-neuropathologic correlation in stroke

True, three-dimensional proton nuclear magnetic resonance imaging at 0.147 tesla was performed postmortem on 2 patients embodying various stroke syndromes, including chronic (4 and 15 years) infarction, subacute (within 1 week) bland infarction, acute (2 days) hemorrhagic infarction, and hematoma secondary to ruptured aneurysm. A third patient, with subcortical arteriosclerotic encephalopathy, so-called Binswanger's disease, was examined antemortem using a 0.6 tesla scanner. Nuclear magnetic resonance images were reconstructed at levels matching the pathologic specimens. Qualitative and, when available, quantitative comparisons between the results of nuclear magnetic resonance imaging and pathology were carried out. Areas of qualitatively prolonged T1 and T2 relaxation times on nuclear magnetic resonance imaging were more extensive than the corresponding areas of chronic infarction noted pathologically and were determined to be infarcts plus the adjacent areas of Wallerian degeneration. Hemorrhagic infarction, without evidence of blood on computed tomography, was found to have mildly prolonged T1 and T2 relaxation times, between those of normal brain and chronic infarction; a 10-day-old hematoma had a very short T1, slightly shorter than that of white matter, and a mildly prolonged T2, with values between those of white and gray matter. Subcortical arteriosclerotic encephalopathy was found to have areas of prolonged T1 and T2 relaxation times involving almost the entire white matter of the corona radiata.

Posterior cerebral artery stenosis

We analyzed the clinical features of symptomatic posterior cerebral artery (PCA) stenosis in 6 patients selected from 15 patients with angiographically documented PCA atherostenosis occurring during a 7-year period. Transient ischemic attacks (TIAs) were the major presentation in 5 patients. A homonymous visual field defect was present in 2 patients. TIA symptoms were predominantly visual or sensory, or both. The most common visual symptom was difficulty seeing to one side. One patient saw flashing lights. Sensory spells were always paresthetic, usually involving the arm and hand and occasionally the face and leg. Three patients had visual and sensory spells together. Two patients with a visual field defect had calcarine infarcts found by computed tomography. All patients were treated with warfarin. During follow-up (4 months to 4 years), no patient had a new stroke in the PCA territory, and only one continued to have TIAs. PCA atherostenosis is rarer then PCA embolic occlusion. In contrast to those with PCA embolism, our patients with PCA atherostenosis had more TIAs and fewer infarcts. The clinical features of PCA stenosis--preponderance of visual and sensory TIAs--distinguish this vascular lesion from stenosis of the middle cerebral artery.

Clinical use of nuclear magnetic resonance imaging in stroke

There are many positive aspects to the use of MRI in the evaluation of cerebrovascular disease. First, the MR imaging technique appears to be essentially without hazard. It does not rely on ionizing radiation, and no intravenous injections of contrast agent are necessary. MRI exploits the tissue's inherent biophysical characteristics to provide superior contrast. Infarctions are well delineated by MRI, often better and earlier than CT. Because of the lack of MRI signal from bone and thus the lack of transverse artifact from bone often seen with CT, lesions in the posterior fossa are very well visualized. With MRI it is possible to obtain images in the transverse, coronal, and sagittal planes, which provides for good evaluation of lesion size and extent. Arteriovenous malformations have been visualized by MRI, but it is still too early to know whether MRI has any detection capability over CT in this disorder. Subdural hematomas have been well visualized by MRI, including cases of isodense subdurals not visualized by CT. On the other hand, MRI has not proven to have any advantage over CT in the evaluation of intracerebral hemorrhage, hemorrhagic infarction, and subarachnoid hemorrhage. In fact, for detection of intracerebral hemorrhage and subarachnoid hemorrhage, CT may be better at the present time. In chronic infarction the surrounding area of Wallerian degeneration may cause the area of infarction to appear larger than it actually is. Hopefully, with further research into the use of different pulse sequence techniques and with good neuropathological correlation, the present limitations of MRI can be eliminated.(ABSTRACT TRUNCATED AT 250 WORDS)

Anticoagulant-related intracerebral hemorrhage

Twenty-four patients had intracerebral hemorrhage while they were being treated with anticoagulants. Hypertension was present in 67% of the cases, head trauma was an uncommon preceding event, and simultaneous bleeding in other organs occurred in only one instance. Neurologic abnormalities progressed for several hours in 58%. Seizures occurred at onset in 12.5%. The location of the hemorrhage was as follows: cerebellum (nine cases), lobar white matter (six), basal ganglia (five), thalamus (two), and hemisphere, unspecified (two). In 61%, the hemorrhages occurred within 6 months of therapy. In 75%, the prothrombin time was beyond 1 1/2 times the control value. Mortality was 62.5%. Survivors had smaller hematomas than did patients with fatal hemorrhage.

MRI and the study of aphasia

Three-dimensional magnetic resonance imaging (MRI) was used to study various aphasia and neurobehavioral syndromes due to embolic or thrombotic cerebral infarction. Two patients are presented to illustrate how MRI may complement, and sometimes improve on, CT for the in vivo demonstration of anatomic changes underlying said syndromes. MRI images were reconstructed at planes selected to match CT, and at coronal planes through the entire anteroposterior extent of the lesions. Both CT and MRI detected lesions; however, MRI provided better differentiation of gray and white matter. Coronal reconstructions aid in optimally visualizing the relationship of lesions to the opercular and perisylvian gyri. CT may be inadequate to define actual extent of lesions, whereas MRI may more clearly show that apparently subcortical lesions can, in fact, involve the cortex as well.

Nuclear magnetic resonance imaging in evaluation of clinical stroke syndromes

Proton nuclear magnetic resonance (NMR) imaging was performed on normal volunteers and patients with various types of clinical strokes. True three-dimensional volumetric data were obtained for subsequent reconstruction of images at various orientations, including transverse, coronal, and sagittal, and for specific matching to x-ray computed tomographic planes. A variety of radiofrequency pulse sequences was used to generate images weighted by the NMR parameters spin density (p) and spin-lattice (T1) and spin-spin (T2) relaxation times. Quantitative T1 data and qualitative T2 information were obtained from appropriate sequences. Proton NMR images embodying T1 information provided adequate delineation of normal intracranial anatomical structure and a high level of gray matter-white matter contrast; high lesion detection sensitivity in various clinical forms of stroke was seen in images providing both T1 and T2 information. T1 and T2 relaxation times were prolonged in embolic, thrombotic, and watershed infarctions as well as in lacunae; shortening of T1 and T2 was found in hematomas. Serpiginous vessels in an arteriovenous malformation were seen that had particular pulse sequences.

Vertebral-basilar posterior cerebral territory stroke--delineation by proton nuclear magnetic resonance imaging

We used three-dimensional proton NMR images to study ischemic infarction in the territory of the vertebral-basilar posterior cerebral circulation. The study includes sixteen cases, eight of which are presented in detail. In seven cases, the infarctions were secondary to demonstrable large artery occlusive disease -- vertebral, basilar, or posterior cerebral. In nine cases, the infarctions were secondary to what was presumably small vessel disease. In fifteen of the sixteen cases, NMR imaging could locate the infarct, inversion recovery and spin-echo pulse sequences being more sensitive than the saturation recovery pulse sequence. This efficiency rests on the high sensitivity of ischemic infarction to changes in T1 and T2 relaxation time, highlighted in the inversion recovery and spin-echo images, respectively. The additional advantages of the three-dimensional approach, and the lack of bone artifact, make NMR imaging superior to CT scanning in identifying areas of infarction in the territory of posterior cerebral circulation.

Central pontine myelinolysis: demonstration by nuclear magnetic resonance

An alcoholic, hyponatremic woman developed central pontine myelinolysis (CPM) and improved from a decerebrate, comatose state to alertness and full ambulation. NMR, using inversion-recovery and spin-echo pulse sequences, was performed sequentially from 4 weeks to 8 months after onset of symptoms and revealed a well-defined lesion with prolonged relaxation times. The lesion was anatomically consistent with CPM and was initially also visualized by CT. NMR showed no definite temporal change in the qualitative appearance of the lesion until the 8-month scan; however, quantitatively, a reduction of relaxation times was noted with each serial study.

Nuclear magnetic resonance imaging in central nervous system disease

From the preliminary work of many investigators, it appears that proton nuclear magnetic resonance (NMR) imaging will have wide application in the diagnostic assessment (and potential management) of patients with vascular, neoplastic, and demyelinating diseases of the central nervous system (CNS). Findings in isolated cases and small series suggest that NMR imaging may play a role in the evaluation of patients with other CNS conditions including hydrocephalus, malformations, infections, developmental and metabolic disorders, and degenerative processes. Because of the dynamic nature of disease processes involving the CNS, the precise meaning of NMR image parameters (rho, T1, and T2) remains unclear. A comprehensive study correlating NMR images in neurologic disease with precise neuropathologic examination is required. In the future, with accurate quantitative measurements of these NMR parameters, in vivo imaging may provide insight into the dynamic nature of neurologic disease.

Periodic nonalternating ocular skew deviation accompanied by head tilt and pathologic lid retraction

A 60-year-old black male with a 13-year history of adult onset diabetes mellitus and hypertension with a previous lacunar stroke suddenly developed a periodic head and eye movement disorder characterized by nonalternating skew deviation, rotatory nystagmus, head tilt, and lid retraction. On CT scan, the patient had a lacunar infarct in the right midbrain in the region of the interstitial nucleus of Cajal, an anatomical area involved with head tilt, torsional eye movement, and skew deviation.

Proton (1H) nuclear magnetic resonance (NMR) imaging in stroke syndromes

The authors briefly review the principles of NMR imaging and illustrate and discuss results from their initial applications of inversion-recovery and spin-echo NMR imaging pulse sequences in humans with diverse pathophysiologies of stroke.