Diffusion-weighted magnetic resonance imaging in patients with subarachnoid hemorrhage

OBJECTIVE: To evaluate the occurrence and distribution of direct brain injury caused by acute subarachnoid hemorrhage (SAH) by the use of magnetic resonance imaging. METHODS: Computed tomography and magnetic resonance imaging, including diffusion-weighted imaging (DWI), were performed in 32 patients with SAH by use of a 1.5-T whole-body superconductive scanner equipped with an echo planar imaging system. In all cases, computed tomographic and magnetic resonance imaging scans were obtained at the time of admission, before angiography and surgical intervention. RESULTS: No abnormalities were revealed by DWI in any of the low-grade SAH patients. However, five (71%) of seven patients diagnosed as having poor-grade SAH (World Federation of Neurosurgical Societies Grades 4 and 5) displayed multiple, patchy focal abnormalities on DWI. Computed tomographic scans obtained at admission failed to clearly demonstrate all of the damaged areas of the brain that were visualized by DWI. These lesions were located in supratentorial cerebral parenchyma, but not in the thalamus, basal ganglia, or cerebellar hemisphere. These multiple widespread lesions exhibiting laminar involvement of the cerebral cortex were not associated with the site of the ruptured aneurysm. CONCLUSION: DWI revealed widespread multifocal lesions in the cerebral cortex of acute poor-grade SAH patients. DWI provides accurate images of all areas of brain damage directly attributable to SAH.     

Venous infarction following the interhemispheric approach in patients with acute subarachnoid hemorrhage

Postoperative venous infarction following aneurysm surgery was studied in 48 patients with anterior communicating artery aneurysms operated on through the interhemispheric approach at the acute stage of subarachnoid hemorrhage (SAH). Of 23 patients whose bridging veins were sacrificed during surgery, 11 (47.8%) showed venous infarction in the frontal lobes. In contrast, only one (5.9%) of 17 patients whose bridging veins were preserved developed cerebral edema. None of eight patients who were operated on after Day 11 (the day of SAH was defined as Day 0) showed this complication, although bridging veins were sacrificed in six of them. Venous infarction following acute aneurysm surgery tended to occur more frequently in patients of higher SAH grade and/or more advanced age, but these correlations were not significant. However, the correlation between the sacrifice of veins and venous infarction was significant (p less than 0.025). Because this potential complication may compromise the benefit of acute aneurysm surgery and cause damage, it is important to preserve the venous system and in some instances to select another surgical approach based on the pattern of venous drainage in the frontal lobe.     

Serum immunocomplexes in patients with subarachnoid hemorrhage

Immunocomplexes (IC) in serum were analyzed in 54 patients with subarachnoid hemorrhage (SAH) from ruptured arterial aneurysms. A previous study had shown that patients with SAH and vasospasm had a significantly higher incidence of ICs in the blood than patients without vasospasm. The aim of the present study was to study how the IC content varied with time and compare this pattern with the clinical picture. Forty-two patients presented clinical or radiological signs of cerebral vasospasm during their hospital stays, whereas 12 patients showed no such signs. The patients with vasospasm had a significantly higher amount of ICs in serum than those without vasospasm. In 37 patients with vasospasm, the changes of IC content during the 1st weeks after SAH correlated well with the clinical course. Data indicated that a high IC content preceded the onset of vasospasm and a low content preceded clinical improvement. This observation supports the idea that the presence of ICs might be the cause and not the result of vasospasm.     

Intraoperative detection of early microvasospasm in patients with subarachnoid hemorrhage by using orthogonal polarization spectral imaging

OBJECTIVE: Changes of major cerebral vessels in patients with subarachnoid hemorrhage (SAH) are well known from routine cerebral angiography. Data on changes in the microcirculation do not exist. This study sought to provide a qualitative and quantitative analysis of the cortical microcirculation after SAH. METHODS: By means of orthogonal polarization spectral imaging, a qualitative and quantitative analysis of cortical microcirculation was performed during aneurysm surgery in 3 patients with an incidental intracerebral aneurysm and 10 patients with SAH. Vessel diameters, red blood cell velocity, and functional capillary density were analyzed before and after the aneurysm was clipped. RESULTS: Initial capillary density in patients with an incidental aneurysm was 91.5 +/- 36.5 cm(-1) (mean +/- standard deviation) compared with 30.5 +/- 13.8 in patients with SAH (P < 0.05). In patients with SAH, capillary density increased significantly to 53.9 +/- 29.1 cm(-1) (P < 0.05) during the operation, as did the frequency of venules with a red blood cell velocity greater than 2 mm/s (P < 0.05). No significant change of arteriolar or venular diameters was observed. However, in patients with SAH, mono- and multisegmental microvasospasms in arterioles were observed, with a reduction of vessel diameters up to 75.1%. CONCLUSION: Orthogonal polarization spectral imaging is a suitable method to study cerebral microcirculation during surgery. In patients with SAH, capillary density is significantly decreased and small arteries and arterioles of the cortical surface exhibit vasospasm that cannot be detected by angiography or transcranial Doppler sonography. These changes may contribute to the initial clinical symptoms and may have an influence on the clinical postoperative course.     

Delayed neurological deficits detected by an ischemic pattern in the extracellular cerebral metabolites in patients with aneurysmal subarachnoid hemorrhage

OBJECT: In the treatment of patients with aneurysmal subarachnoid hemorrhage (SAH), early occlusion of the aneurysm is necessary as well as monitoring and treatment of complications following the primary bleeding episode. Monitoring with microdialysis has been studied for its ability to indicate and predict the occurrence of delayed ischemic neurological deficits (DINDs) in patients with SAH. METHODS: In 42 patients with aneurysmal SAH microdialysis monitoring of metabolites was performed using a 0.3-microl/minute perfusion flow over several days, and the results were correlated to clinical events and to brain infarction observed on computerized tomography scans. The microdialysis probe was inserted into the territory of the parent artery of the aneurysm. The authors defined an ischemic pattern as increases in the lactate/glucose (L/G) and lactate/pyruvate (L/P) ratios that were greater than 20% followed by a 20% increase in glycerol concentration. This ischemic pattern was found in 17 of 18 patients who experienced a DIND and in three of 24 patients who did not experience a delayed clinical deterioration. The ischemic pattern preceded the occurrence of a DIND by a mean interval of 11 hours. Maximum L/G and L/P ratios did not correlate with the presence of DIND or outcome, and there was no association between the glycerol level and subsequent brain infarction. CONCLUSIONS: Microdialysis monitoring of the cerebral metabolism in patients with SAH may predict with high sensitivity and specificity the occurrence of a DIND. Whether an earlier diagnosis results in better treatment of DINDs and, therefore, in overall better outcomes remains to be proven, as it is linked to an efficacious treatment of cerebral vasospasm.     

Multiple interstitial substances measured by microdialysis in patients with subarachnoid hemorrhage

OBJECTIVE: Intracerebral microdialysis is a tool to monitor metabolic disturbances in the brains of patients with severe head injuries or subarachnoid hemorrhage (SAH). In the search for putative indicators of primary and secondary brain damage, we measured multiple metabolites in the dialysates of patients with SAH, to elucidate their significance for the outcomes of the patients as well as their temporal profiles of liberation after the insult. METHODS: Microdialysis probes were placed, with a ventriculostomy catheter for drainage of cerebrospinal fluid, into a frontal lobe of 10 patients with aneurysmal SAH, for 4.6 +/- 0.5 days. Amino acids, metabolites of glycolysis, purines, catecholamines, and nitric oxide oxidation byproducts were measured by high-performance liquid chromatography. Spearman's correlation coefficient and Student's t test were used to compare the levels of the metabolites with the outcomes of the patients, as assessed using the Glasgow Outcome Scale, 3 months after the ictus. RESULTS: For patients with unfavorable outcomes (Glasgow Outcome Scale scores of 1-3), which were primarily associated with the development of large infarctions, dialysate levels of excitatory amino acids increased up to 30-fold, those of lactate up to 10-fold, and those of nitrite up to 5-fold, compared with normal levels observed for patients with favorable outcomes (Glasgow Outcome Scale scores of 4 or 5). When average peak concentrations in the dialysates of patients with favorable and unfavorable outcomes were compared, significantly higher levels of excitatory amino acids, taurine, lactate, and nitrite, but not of purines and catecholamines, were observed for those with poor outcomes (P < 0.05). With respect to the temporal profiles of the average metabolite concentrations, the significantly increased levels of amino acids observed for patients with poor outcomes followed a biphasic course, with maximal concentrations on the first and second days or the seventh day after the insult (P < 0.01). CONCLUSION: These data confirm the usefulness of excitatory amino acids and lactate as major parameters for neurochemical monitoring for patients threatened by acute cerebral disorders. Other substances, such as taurine and nitrite, were also demonstrated to be potentially predictive. Release of these substances into the extracellular fluid of the brain might be particularly relevant for the development of secondary brain damage after SAH, e.g., infarction or brain swelling.     

Neurogenic pulmonary edema in patients with subarachnoid hemorrhage

Neurogenic pulmonary edema (NPE), leading to cardiopulmonary dysfunction, is a potentially life-threatening complication in patients with aneurysmal subarachnoid hemorrhage (SAH). We sought to assess the clinical presentation and risk factors for the development of NPE after SAH. The database contained prospectively collected information on 477 patients with SAH. Baseline characteristics, clinical and radiologic severity of the bleeding, localization of the ruptured aneurysm, and clinical outcome of patients with NPE were compared with those of patients without NPE. Further, in patients with NPE, intracranial pressure, serum cardiac biomarkers, and hemodynamic parameters during the acute phase were evaluated retrospectively. The incidence of NPE was 8% (39 of 477 patients). Most patients with NPE were severely impaired and all of them presented with radiologically severe hemorrhage. The incidence of NPE was significantly higher in patients with ruptured aneurysm in the posterior circulation. Elevated intracranial pressure was found in 67%, pathologically high cardiac biomarkers in up to 83% of patients with NPE. However, no patient suffered from persistent cardiac dysfunction. Compared with patients without NPE, patients with NPE showed poor neurologic outcome (Glasgow outcome scale 1 to 3 in 25% vs.77% of patients). In conclusion, patients with NPE have a high mortality rate more likely due to their severity grade of the bleeding. Morbidity and mortality due to cardiopulmonary failure might be reduced by appropriate recognition and treatment. The awareness of and knowledge about occurrence, clinical presentation, and treatment of NPE, are essential for all those potentially confronted with patients with SAH in the acute phase.     

Multishot diffusion-weighted imaging features in spinal cord infarction

OBJECTIVE: The purpose of this study was to use a multishot, navigator-corrected, echo-planar (EP) pulse sequence to perform clinical diffusion-weighted imaging (DWI), analyze the DWI findings in ischemic spinal cord lesions, and discuss the value of DW magnetic resonance imaging (MRI) in distinguishing infarction (especially in the subacute stage) from inflammatory diseases and tumors of the spinal cord. METHODS: Six patients (two male, four female) with typical sudden onset of neurologic deficits caused by spinal cord ischemia were evaluated. There were no definite etiologies in these patients. Three cases occurred in the thoracolumbar region and three others occurred in the cervical cord. DWI was performed within 1-12 days after the initial neurologic symptoms by using a Philips Gyroscan 1.5 T MR system. Four patients had other scans including contrast-enhanced MRI and fluid-attenuated inversion recovery (FLAIR) scans. Two cases were followed up with MR images in 3 months. All the patients were imaged using a multishot, navigator-corrected, EP pulse sequence; apparent diffusion coefficient (ADC) values were calculated on the sagittal-oriented plane. RESULTS: MR abnormalities were demonstrated on sagittal T2-weighted images with "patch-like" or "strip-like" hyperintensities (six of six) and spinal cord enlargement (five of six). Axial T2-weighted images showed bilateral (six of six) hyperintensities. In one patient, only the posterior spinal artery territory was involved. The spinal cord was mainly affected at the cervical (three of six) and thoracolumbar (three of six) regions. Two cases involved the conus medullaris (T10-L1). The intensity of lesion signals in DW images depended on how soon after the onset of illness the scan was carried out and whether hemorrhage had occurred. In this group of patients, ADC values of lesions ranged from 0.23 x 10(-3) to 0.47 x 10(-3) mm2/s (average value 0.36 +/- 0.10 x 10(-3) mm2/s), markedly lower than the values of normal parts (average value 0.89 +/- 0.08 x 10(-3) mm2/s). There were obviously significant differences between areas with lesions and normal regions (P < 0.01). All cases had better signal contrast in DW images than in T2-weighted images. Dynamic or repeated DWI examinations may help analyze the degree of injury and recovery. Most lesions (three of four) showed nonenhanced effects in the contrast-enhanced MRI except one lesion, which showed irregular slight enhancement. FLAIR images showed poor signal contrast between lesions and normal tissue and thus are not fit for displaying infarct lesions. CONCLUSIONS: MRI is useful in detecting spinal cord infarction. DWI (especially multishot DWI) of the spinal cord may provide additional information for the assessment of ischemic changes and help improve in differentiating diagnosis.     

Magnetic resonance imaging of acute subarachnoid hemorrhage

The feasibility, safety, and diagnostic value of magnetic resonance (MR) imaging versus computerized tomography (CT) scanning were compared in 30 patients with clinical evidence of subarachnoid hemorrhage. Subarachnoid blood was identified more often and more information was available about the site and source of the hemorrhage on MR imaging than on CT. Magnetic resonance imaging could be used safely both before and after the operation, provided that nonferromagnetic clips were used and that comprehensive monitoring and cardiorespiratory support were available. Postoperative studies showed that artifacts from metallic implants and from patient movement caused less image degradation on MR images than on CT scans.     

Preoperative sedation with dexmedetomidine in patients with aneurysmal subarachnoid hemorrhage

BACKGROUND: Dexmedetomidine could be beneficial for preoperative sedation of patients with aneurysmal subarachnoid hemorrhage (SAH) because of its sympathetic suppressive effect without respiratory depression. METHODS: Thirteen patients were sedated with continuous intravenous administration of dexmedetomidine (group D) and 13 were with intermittent intravenous administration of diazepam and pentazocine (group C). RESULTS: Blood pressure (BP) and heart rate (HR) on admission to OR in group D were lower than those in group C. On tracheal intubation, BP and HR increased in both groups, but the differences between the values before and after the intubation were larger in group C than in D. CONCLUSIONS: Preoperative dexmedetomidine infusion is suitable for patients with SAH.     

Outcome in patients with subarachnoid hemorrhage treated with antiepileptic drugs

OBJECT: Prophylactic use of antiepileptic drugs (AEDs) in patients admitted with aneurysmal subarachnoid hemorrhage (SAH) is common practice; however, the impact of this treatment strategy on in-hospital complications and outcome has not been systematically studied. The goal in this study was twofold: first, to describe the prescribing pattern for AEDs in an international study population; and second, to delineate the impact of AEDs on in-hospital complications and outcome in patients with SAH. METHODS: The authors examined data collected in 3552 patients with SAH who were entered into four prospective, randomized, double-blind, placebo-controlled trials conducted in 162 neurosurgical centers and 21 countries between 1991 and 1997. The prevalence of AED use was assessed by study country and center. The impact of AEDs on in-hospital complications and outcome was evaluated using conditional logistic regressions comparing treated and untreated patients within the same study center. RESULTS: Antiepileptic drugs were used in 65.1% of patients and the prescribing pattern was mainly dependent on the treating physicians: the prevalence of AED use varied dramatically across study country and center (intraclass correlation coefficients 0.22 and 0.66, respectively [p < 0.001]). Other predictors included younger age, worse neurological grade, and lower systolic blood pressure on admission. After adjustment, patients treated with AEDs had odds ratios of 1.56 (95% confidence interval [CI] 1.16-2.10; p = 0.003) for worse outcome based on the Glasgow Outcome Scale; 1.87 (95% CI 1.43-2.44; p < 0.001) for cerebral vasospasm; 1.61 (95% CI 1.25-2.06; p < 0.001) for neurological deterioration; 1.33 (95% CI 1.01-1.74; p = 0.04) for cerebral infarction; and 1.36 (95% CI 1.03-1.80; p = 0.03) for elevated temperature during hospitalization. CONCLUSIONS: Prophylactic AED treatment in patients with aneurysmal SAH is common, follows an arbitrary prescribing pattern, and is associated with increased in-hospital complications and worse outcome.     

Asymptomatic versus symptomatic infarcts from vasospasm in patients with subarachnoid hemorrhage: serial magnetic resonance imaging

OBJECTIVE: By use of serial magnetic resonance imaging (MRI), we prospectively investigated the incidence of and the risk factors associated with infarction caused by vasospasm with or without a delayed ischemic neurological deficit (DIND) in patients with subarachnoid hemorrhage (SAH). METHODS: In 125 patients who underwent surgery for early aneurysms, postoperative MRI scans were obtained at four time points. We defined an infarct from vasospasm as a new lesion not present on the initial MRI within 3 days after SAH and therefore not attributable to primary brain damage or surgical complications. RESULTS: Overall, symptoms of infarction (i.e., DIND) occurred in 38% of patients (48 of 125); DIND with a new infarct on MRI was evident in 34% (43 patients), whereas 4% (5 patients) showed no new lesion but had a DIND. However, 29 patients (23%) showed a new infarct but no DIND on MRI studies (asymptomatic infarction). Asymptomatic ischemic lesions due to vasospasm tended to involve noneloquent brain areas in the territory of intraparenchymal perforators. Multivariate analysis identified variables associated with symptomatic infarction to be of poor SAH grade, advanced age of the patient, angiographic findings of vasospasm, multiple cortical infarcts on MRI studies consistent with vasospasm, and chronic hydrocephalus. CONCLUSION: Analysis of the data confirmed the occurrence of asymptomatic infarcts due to vasospasm. These infarcts often developed in noneloquent areas representing perforator territory. MRI investigation of vasospastic lesions referable to intraparenchymal vessels such as perforators complements the study of extraparenchymal major vessel vasospasm in patients with SAH by computed tomographic angiography.     

Referral pattern of patients with aneurysmal subarachnoid hemorrhage

The referral pattern of 334 patients admitted to a neurosurgical clinic with aneurysmal subarachnoid hemorrhage (SAH) was analyzed. Forty-nine percent of the patients were admitted after the day following the SAH. Failure of patients to seek prompt medical care was a cause of delay in 29 patients and of physician diagnostic errors in 95 patients. Common misdiagnoses included migraine, mental exhaustion, sinusitis, and influenza. A delay at the referring hospital was observed in 97 patients. Early intervention is important for the optimal management of patients with SAH. Educating the public, medical students, and physicians about the signs and symptoms of SAH and the importance of prompt therapy is likely to improve overall outcome after aneurysmal rupture.     

Early versus late intracranial aneurysm surgery in subarachnoid hemorrhage

The management results in 244 patients admitted to one institution within 3 days of aneurysmal subarachnoid hemorrhage (SAH) from January, 1979, to December, 1985, were analyzed with respect to the timing of surgical intervention. Twenty-six patients died prior to surgery. Patients surviving to surgery were divided into three groups according to the interval between preadmission SAH and surgery: 0 to 3 days (85 cases), 4 to 9 days (83 cases), and 10 or more days (50 cases). Of the patients who were categorized neurologically into Botterell Grades 1 and 2 (Hunt and Hess Grades I to III) on admission, 87% had an excellent or good result on follow-up evaluation. Patients undergoing surgery 0 to 3 days after SAH had a statistically significant increase in the incidence of postoperative ischemic symptoms (p less than 0.005), which was balanced by similar complications preoperatively in the 10-day post-SAH surgical group. Most rebleeds occurred before admission but delaying surgery did increase the risk of rebleeding in the hospital (p less than 0.0005). Management morbidity and mortality occurred primarily as a direct result of a severe initial hemorrhage; thus, the measured benefits of early surgery were less than might have been predicted.