Measurement of CP-violating asymmetries in B0 decays to CP eigenstates

We present measurements of time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurement uses a data sample of 23x10(6) Upsilon(4S)-->BbarB decays collected by the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we find events in which one neutral B meson is fully reconstructed in a CP eigenstate containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry, which in the standard model is proportional to sin2beta, is derived from the decay time distributions in such events. The result is sin2beta = 0.34+/-0.20 (stat)+/-0.05 (syst).

Stent-assisted angioplasty of intracranial vertebrobasilar atherosclerosis: an initial experience

OBJECT

Patients with intracranial vertebrobasilar artery (VBA) atherosclerotic occlusive disease have few therapeutic options. Unfortunately, VBA transient ischemic attacks (TIAs) herald a lethal or devastating event within 5 years in 25 to 30% of patients. The authors report their initial experience with eight patients in whom medically refractory TIAs secondary to intracranial posterior circulation atherosclerotic occlusive lesions were treated with stent-assisted angioplasty.

METHODS

Eight patients (six men), ranging in age from 43 to 77 years, experienced signs and symptoms of VBA insufficiency despite combination therapy with warfarin and antiplatelet agents. Angiographic studies revealed severe distal vertebral (four patients), proximal basilar (one patient), or proximal and midbasilar stenoses (three patients). Aspirin and clopidogrel were administered for 3 days before primary angioplasty and stent placement, and this regimen was maintained by the patients on discharge. Patients underwent heparinization during the procedure and were given a bolus and 12-hour infusion of abciximab. A neurologist specializing in stroke evaluated all patients before and after the procedure. The VBAs in all patients were successfully revascularized with 7 to 28% residual stenosis. Six patients experienced no neurological complications. One patient died the evening of the procedure due to a massive subarachnoid hemorrhage. Two patients had groin hematomas, one developed congestive heart failure, and one had transient encephalopathy. All surviving patients are asymptomatic up to 8 months postoperatively.

CONCLUSIONS

Although primary intracranial VBA angioplasty with stent insertion is technically feasible, complications associated with the procedure can be life threatening. As experience is gained with this procedure, it may be offered routinely as an alternative therapy to patients with medically refractory posterior circulation occlusive disease that may develop into catastrophic VBA insufficiency.

Head computed tomography in medical intensive care unit patients: clinical indications

OBJECTIVE

To assess whether clinical variables might be useful in selecting patients who will have an acute intracranial abnormality seen in head computed tomographic scans (HCT).

DESIGN

Retrospective study.

SETTING

Medical intensive care unit (MICU) in a tertiary teaching hospital.

MEASUREMENTS

Medical records of patients admitted to the MICU who underwent HCT between January 1, 1994, and December 31, 1995, were reviewed. Patients with acute intracranial abnormalities (HCT-positive) and those without new acute findings (HCT-negative) were compared on various clinical variables, including demographics, indications for obtaining the HCT (mental status change, neurologic deficit, fever, seizures), coagulation profiles, when the HCT was performed (at admission or after admission), and ordering physician.

MAIN RESULTS

Of 297 HCTs obtained in 230 patients, 37% (109/297) were positive. When the clinical variables were examined univariately, only the presence of a neurologic deficit (70% vs. 37%; difference, 33%; p < .001) differed significantly between positive and negative HCTs. Multivariate analysis confirmed that only the frequency of a new neurologic deficit differed significantly in the two groups (p < .001; odds ratio, 3.9; 95% confidence interval, 2.3-6.4). In patients without neurologic deficits, only the presence of seizures was associated with a positive HCT (p < .01: logistic regression). The presence of either neurologic deficit or seizures best predicted a positive HCT: sensitivity 0.81, specificity 0.53, positive predictive value 0.50, and negative predictive value 0.83.

CONCLUSION

Among MICU patients, the presence of either neurologic deficit or seizures is associated with the presence of an acute intracranial abnormality seen in HCT, but the association is not powerful enough to reliably depend on these clinical variables to select patients for HCTs in the MICU.

Hemorrhage detected using MR imaging in the setting of acute stroke: an in vivo model

BACKGROUND AND PURPOSE

The treatment algorithm for acute cerebrovascular accidents has traditionally sorted these accidents as either hemorrhagic or nonhemorrhagic, and MR imaging, with its ability to allow expeditious assessment of vascular substrates and regional blood volume, is well suited for this purpose. Our purpose was to delineate the accuracy of MR imaging in acute, hemorrhagic forms of stroke during the time frame considered beneficial for intervention in an animal model.

METHODS

Eighteen dogs with small, iatrogenic parenchymal, subarachnoid hemorrhage (SAH), or both were serially scanned over the initial 6-hour postictal period. Confirmatory pathologic specimens and 3-hour postictal CT scans were obtained in all animals. The MR and CT studies were then interpreted in a blinded fashion by two neuroradiologists for the presence of hemorrhage. The results were subjected to receiver operating characteristic analysis.

RESULTS

MR imaging depicted acute parenchymal hemorrhage and SAH with a high degree of accuracy at 1.5 T. This finding was independent of each of the time points studied during the 6-hour window. For SAH, the MR accuracy for reader 1 was 0.86 (95% CI, 0.76-0.97); for reader 2, accuracy was 0.85 (95% CI, 0.71-0.99). The CT accuracy for the two readers was 0.42 (95% CI, 0.26-0.58) and 0.66 95% CI, 0.43-0.89), respectively. Fluid-attenuated inversion-recovery images improved the conspicuity of SAH on MR images and, along with spin-density-weighted spin-echo sequences, helped to establish the hemorrhagic nature. For parenchymal hemorrhage, the MR accuracy for reader 1 was 0.90 (95% CI, 0.81-0.99); for reader 2, accuracy was 0.93 (95% CI, 0.84-1.00). With CT, the accuracy of reader 1 was 0.91 (95% CI, 0.85-0.97) whereas for reader 2 accuracy was 0.76 (95% CI, 0.69-.83). Parenchymal hemorrhage detection and diagnosis was best with T2*-weighted gradient-echo images.

CONCLUSION

MR imaging with appropriately selected sequences appears able to provide information regarding the presence (or absence) of hemorrhage in an acute stroke model requisite to the initiation of treatment.

Detachable balloon embolization: concomitant use of a second safety balloon

We describe a relatively unusual case of carotid cavernous fistula in association with a persistent trigeminal artery, presumably related to aneurysm rupture near the carotid origin of the vessel. We emphasize the use of a second, nondetachable balloon solely for the purpose of stabilizing placement of the first device at the time of detachment.

Cerebral embolism associated with left ventricular assist device support and successful therapy with intraarterial urokinase

A patient with a bioprosthetic aortic valve sustained a cerebral embolism during support with an implantable left ventricular assist device. This was lysed with intraarterial urokinase with complete resolution of the neurological deficit. Subsequently the patient underwent heart transplantation and remains neurologically intact. This case report is the first successful use of thrombolysis for cerebral embolism associated with a mechanical assist device.

Intra-arterial thrombolysis for perioperative stroke after open heart surgery

Recent major surgery is an exclusion criterion for thrombolysis. Six patients with acute ischemic stroke underwent intra-arterial thrombolysis after recent open heart surgery without clinically significant bleeding complications, although one patient developed a small, asymptomatic cerebellar hemorrhage. Intra-arterial thrombolysis may be an option for patients with cerebral embolism in the perioperative period.

Angioplasty and primary stenting of the subclavian, innominate, and common carotid arteries in 83 patients

PURPOSE

The initial and long-term results of angioplasty and primary stenting for the treatment of occlusive lesions involving the supra-aortic trunks were studied.

METHODS

All patients in whom angioplasty and stenting of the supra-aortic trunks was attempted were included in a prospective registry. Results are, therefore, reported on an intent-to-treat basis. The preprocedural and postprocedural clinical records, arteriograms, and noninvasive vascular laboratory examinations of 83 patients (41 men [49.4%] and 42 women [50.6%]; mean age at intervention, 63 years) in whom endovascular repair of the subclavian (66, 75.9%), left common carotid (14, 16.1%), and innominate (7, 8.0%) arteries was attempted were retrospectively reviewed.

RESULTS

Initial technical success was achieved in 82 of 87 procedures (94.3%). The inability to cross 4 complete subclavian occlusions and the iatrogenic dissection of 1 common carotid artery lesion accounted for the 5 initial failures. Complications occurred in 17.8% of 73 subclavian and innominate procedures, including access-site bleeding in 6 and distal embolization in 2. Ischemic strokes occurred in 2 of 14 common carotid interventions (14.3%), both of which were performed in conjunction with ipsilateral carotid bifurcation endarterectomy. The 30-day mortality rate was 4.8% for the entire group. By means of life-table analysis, 84% of the subclavian and innominate interventions, including initial failures, remain patent by objective means at 35 months. No patients have required reintervention or surgical conversion for recurrence of symptoms. Of the 11 patients available for follow-up study who underwent common carotid interventions, 10 remain stroke-free at a mean of 14.3 months.

CONCLUSION

Angioplasty and primary stenting of the subclavian and innominate arteries can be performed with relative safety and expectations of satisfactory midterm success. Endovascular repair of common carotid artery lesions can be performed with a high degree of technical success, but should be approached with caution when performed in conjunction with ipsilateral bifurcation endarterectomy.

Central nervous system complications after lung transplantation

PURPOSE

This study describes the central nervous system (CNS) events after lung transplantation.

METHODS

A chart review of all lung transplant recipients (LTR) to collect the clinical and neuroimaging data for CNS events defined as seizures, severe headaches, confusion, or stroke.

RESULTS

Twenty-six patients of 100 LTRs from 1990 through 1995 had a CNS event; more than one event occurred in 5 patients for a total of 32 events. Severe headache was most common, occurring in 14 patients, followed by seizures in 10, stroke in 5, and confusion in 3. The CNS event was related to infection in three of the 26 patients. Of all evaluations performed, magnetic resonance imaging (MRI) identified the most abnormalities, the most common being white matter changes consistent with cyclosporine toxicity. Cyclosporine levels were elevated in slightly more than half of the patients. Hypomagnesemia was present in three of 10 patients with seizures. Prognosis for recovery from these complications was good, with only five patients having ongoing problems with headaches, one requiring long term anticonvulsant therapy, three having minor or no limitations from stroke and no long-term problems with confusion. One patient with seizures resulting from an aspergilloma died.

CONCLUSION

CNS events occur commonly in LTRs, mostly related to cyclosporine toxicity or infection. MRI identifies more abnormalities than computed tomography. These events were not consistently associated with documented high cyclosporine levels and hypomagnesemia. In spite of significantly abnormal MRIs, the functional outcome is favorable.

Automatic detection of ground glass opacities on lung HRCT using multiple neural networks

The purpose of this study was to implement neural networks and expert rules for the automatic detection of ground glass opacities (GG) on high-resolution computed tomography (HRCT). Different approaches using self-organizing neural nets as well as classifications of lung HRCT with and without the use of explicit textural parameters have been applied in preliminary studies. In the present study a hybrid network of three single nets and an expert rule was applied for the detection of GG on 120 HRCT scans from 20 patients suffering from different lung diseases. Single nets alone were not capable to reliably detect or exclude GG since the false-positive rate was greater than 100 % with regard to the area truly involved, more than 50 pixels throughout, and the true-positive rate was greater than 95 %. The hybrid network correctly classified 91 of 120 scans. Mild GG was false positive in 15 cases with less than 50 pixels, which was judged not clinically relevant. The pitfalls were: partial volume effects of bronchovascular bundles and the chest wall. Motion artefacts and diaphragm were responsible for 11 misclassifications. Hybrid networks represent a promising tool for an automatic pathology-detecting system. They are ready to use as a diagnostic assistant for detection, quantification and follow-up of ground glass opacities, and further applications are underway.

Comparison of examination times between CT scanners: are the newer scanners faster?

OBJECTIVE

The purpose of this study was to determine if a newer technology helical CT scanner can reduce CT examination times.

MATERIALS AND METHODS

Data from 1049 CT examinations were recorded prospectively during a 5-week period. "Room time" was defined as the time each patient spent in the CT room (time patient exited minus time patient entered) and "scanner time" was defined as the time a scanner was dedicated to a specific patient (longer of either time that image processing was complete minus time patient entered room, or total time that patient spent in the scanner room). Data to calculate the room and scanner times were recorded along with the scanner type, examination protocol, and five other covariates. Both times were calculated for the 10 most common examination protocols (n = 769 patients) and compared between the older and newer model CT scanner using analysis of covariance models. The most common protocols were abdomen and pelvis (n = 211); head (n = 146); chest (n = 99); simple sinus (n = 99); and chest, abdomen, and pelvis (n = 68).

RESULTS

The mean room and scanner times, adjusted for covariates, were both significantly shorter for the newer scanner (p = .0001). The results for room time were statistically significant for six of the 10 examination protocols (84% of examinations). Likewise, the results for scanner time were statistically significant for four examination protocols (68% of examinations). Examination times were longer for inpatients (p = .0001) and when problems occurred during the examination (p = .0001). Sex and age did not significantly affect examination times (p > .08).

CONCLUSION

The newer helical CT scanner we studied significantly reduced the time for many types of examinations.

Improvement of spiral MRI with the measured k-space trajectory

The k-space trajectory of a spiral imaging sequence was measured with a self-encoding technique. The image quality improved dramatically when reconstructed with the measured k-space trajectory. There were substantial artifacts in images reconstructed with the derived k-space trajectory under the assumption of gradient system linearity. The results indicated the non-linearity of the gradient system and the effectiveness of the correction technique.

Basilar artery rethrombosis: successful treatment with platelet glycoprotein IIB/IIIA receptor inhibitor

We describe the use of abciximab to prevent rethrombosis of the basilar artery after transluminal angioplasty. A 60-year-old patient with vertebral basilar insufficiency and acute occlusion of the basilar artery underwent revascularization with urokinase and angioplasty. Despite the repeated use of urokinase and angioplasty under anticoagulation with heparin, the basilar artery immediately rethrombosed. In a final attempt to prevent rethrombosis, abciximab was administered before the final angioplasty, resulting in a widely patent basilar artery and no rethrombosis.

Endovascular occlusion of the carotid or vertebral artery with temporary proximal flow arrest and microcoils: clinical results

PURPOSE

To determine the clinical effectiveness of parent artery occlusion of the carotid or vertebral artery by means of temporary proximal flow arrest and microcoils.

METHODS

Nineteen parent artery occlusions (15 carotid, four vertebral) were performed in 19 patients who successfully passed a balloon test occlusion. In these patients, endovascular occlusion of the carotid or vertebral artery was accomplished with the use of temporary proximal flow arrest and microcoils.

RESULTS

All 19 parent arteries were occluded. Eighteen patients (95%) had good outcomes and one (5%) had a poor outcome. Fourteen patients (74%) had no complications and five (26%) had complications, of whom only one was left with a permanent neurologic deficit. Three (60%) of the complications were the result of delayed ischemic events after parent artery occlusion and were not predicted by balloon test occlusion.

CONCLUSION

Endovascular occlusion with temporary proximal flow arrest and microcoils can be done effectively and successfully. The predictive value of the balloon test occlusion is the major complicating factor, as it is with balloon occlusion. This technique offers an additional tool that can be used for endovascular occlusion of the carotid or vertebral artery and seems to be less difficult technically. It is our primary technique for parent artery occlusion.

Autopsy findings of fatal complication of posterior cerebral circulation angioplasty

Percutaneous transluminal angioplasty is a technique widely used to treat stenotic atherosclerotic lesions of the coronary arteries. This technique is currently gaining acceptance for the treatment of cerebral atherosclerotic disease. Autopsy findings of fatal complications of percutaneous transluminal angioplasty of the posterior cerebral circulation have, to our knowledge, not yet been published. We report the case of a patient with severe diffuse atherosclerosis of vertebral and basilar arteries, whose symptoms were not ameliorated with standard medical therapy. Transfemoral percutaneous transluminal angioplasty was performed in an attempt to reestablish blood flow in the posterior cerebral circulation by angioplasty of a severely stenotic basilar artery. The patient suffered a fatal complication during the procedure due to rupture of the basilar artery by the percutaneous transluminal angioplasty guidewire apparatus, leading to massive subarachnoid hemorrhage. We report the clinical and autopsy findings of this case.

Rare lesions of the posterior fossa with initial retrocochlear auditory and vestibular complaints

OBJECTIVE

To catalog a series of rare lesions of the posterior fossa that appeared with unusual initial retrocochlear symptoms and signs and to make the reader more aware of these unusual lesions with a view to improving initial assessment and treatment planning.

STUDY DESIGN

The study was a retrospective case review of seven patients.

SETTING

Multidisciplinary team evaluation in a tertiary hospital referral center.

PATIENTS

Patients with unusual lesions of the cerebellopontine angle and posterior fossa with initial retrocochlear symptoms and signs were included.

INTERVENTIONS

Diagnostic and therapeutic.

MAIN OUTCOME MEASURES

Hearing preservation and balance function.

RESULTS

The rare lesions presented include two aneurysms of the anterior inferior cerebellar artery, one giant basilar artery aneurysm, and one each of the following neoplasms: endodermal cyst, choroid plexus papilloma, cavernous angioma, and ependymoma.

CONCLUSIONS

A close working relationship among the otolaryngologist, neurotologist, neurosurgeon, and neuroradiologist is necessary to accurately evaluate these unusual cerebellopontine angle lesions and effect the best treatment outcome.

Endovascular management of unusual aneurysms of the axillary and subclavian arteries

PURPOSE

Aneurysms of the upper extremity arteries are uncommon and may be difficult to manage with standard surgical techniques. We report the exclusion of three axillary-subclavian aneurysms with covered stents.

METHODS AND RESULTS

Palmaz stents were covered with either polytetrafluoroethylene (2 cases) or brachial vein and deployed to exclude pseudoaneurysms in 1 axillary (ruptured) and 2 left subclavian arteries. Two of the patients had advanced cancer and died within 52 days and 3 months of treatment, but their aneurysms were occluded at the time of their death. The repair in the third patient is patent at 9 months.

CONCLUSIONS

Endovascular exclusion of axillary and subclavian aneurysms with covered stents may offer a useful alternative to operative repair, particularly in patients with significant comorbidities.

Early treatment of ruptured aneurysms with Guglielmi detachable coils: effect on subsequent bleeding

The major causes of mortality and morbidity in patients surviving the rupture of a saccular aneurysm are subsequent bleeding and vasospasm. The purpose of this study was to evaluate the influence of early treatment of ruptured aneurysms with Guglielmi detachable coils on the incidence of subsequent bleeding. Thirteen patients were treated within 72 hours of initial aneurysm rupture with Guglielmi detachable coils. Excluding three patients who died 2, 4, and 12 weeks after initial hemorrhage, all others have been followed up for intervals between 6 and 36 months (mean, 16 mo). None of these have had either clinical or radiographic evidence of subsequent bleeding. Assuming that there is a 30% incidence of subsequent bleeding in conservatively (nonsurgically) treated patients, the 0% subsequent bleed rate observed in this subgroup was significant at a P value of 0.01. Only one procedure-related complication occurred in this series, and 9 of 13 (69%) aneurysms were 100% occluded at the time of initial treatment. All aneurysms were at least 90% occluded at the end of initial treatment. In addition to reducing the risk of subsequent bleeding, early treatment facilitated the institution of an aggressive approach for management of both vasospasm and increased intracranial pressure. Patient outcome, as measured by the Glasgow Outcome Scale, was good in 9 of 13 (69%), poor in 1 of 13 (8%), and death in 3 of 13 (23%) patients. The results of this study suggest that early Guglielmi detachable coil treatment of ruptured aneurysms may be effective in reducing the incidence of subsequent bleeding and can be performed with a low incidence of complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Hyperintense disks on T1-weighted MR images: correlation with calcification

PURPOSE

To determine if calcification in the intervertebral disk is associated with hyperintensity on T1-weighted spin-echo magnetic resonance (MR) images.

MATERIALS AND METHODS

Sagittal T1-weighted MR images that showed one or more hyperintense intervertebral disks and correlative computed tomographic (CT) scans, plain radiographs, or both, were obtained in 11 patients retrospectively and in 43 patients prospectively. Six patients underwent MR imaging with a fat-suppression technique. Histologic analysis of two disks was performed.

RESULTS

Absence of calcification was associated with disks that were isointense relative to normal disks (P < .001), mild to moderate calcification was associated with hyperintense disks (P < .001 and P = .004 [two readers]), and both mild to moderate and marked calcifications were associated with hypointense disks (P < .001). Fat suppression resulted in a decrease in hyperintense signal in two patients.

CONCLUSION

The results indicate that hyperintensity is associated with calcification. In the absence of clinical findings that suggest other causes, hyperintense disks are suggestive of degenerative disk disease.

Naloxone has no effect on ethanol-induced impairment of psychomotor performance in man

In a study designed to investigate the effect of naloxone on ethanol-induced performance deficits in man, ethanol (0.75 g/kg) and naloxone (0.4 mg) or saline were administered to 39 volunteers in a double-blind fashion. Psychomotor performance was assessed on a battery of tests (standing steadiness, pursuit rotor, simple and complex reaction times, a speeded number test and the Vienna Determination Apparatus) and blood and breath ethanol concentrations were monitored. Two experiments were performed: in Experiment 1 ethanol was given before naloxone and in Experiment 2 naloxone was administered before ethanol. There were no significant differences in either blood or breath ethanol concentrations at any time between the ethanol + naloxone and ethanol + saline groups in either Experiment 1 or 2. Although ethanol produced a significant decrement on most of the performance measures, naloxone was without effect. There was no suggestion of ethanol impairment being moderated by naloxone, whether it was given before or after ethanol.