Quantifying Intracranial Aneurysm Wall Permeability for Risk Assessment Using Dynamic Contrast-Enhanced MRI: A Pilot Study.

BACKGROUND AND PURPOSE: Pathological changes in the intracranial aneurysm wall may lead to increases in its permeability; however the clinical significance of such changes has not been explored. The purpose of this pilot study was to quantify intracranial aneurysm wall permeability (K(trans), VL) to contrast agent as a measure of aneurysm rupture risk and compare these parameters against other established measures of rupture risk. We hypothesized K(trans) would be associated with intracranial aneurysm rupture risk as defined by various anatomic, imaging, and clinical risk factors. MATERIALS AND METHODS: Twenty-seven unruptured intracranial aneurysms in 23 patients were imaged with dynamic contrast-enhanced MR imaging, and wall permeability parameters (K(trans), VL) were measured in regions adjacent to the aneurysm wall and along the paired control MCA by 2 blinded observers. K(trans) and VL were evaluated as markers of rupture risk by comparing them against established clinical (symptomatic lesions) and anatomic (size, location, morphology, multiplicity) risk metrics. RESULTS: Interobserver agreement was strong as shown in regression analysis (R(2) > 0.84) and intraclass correlation (intraclass correlation coefficient >0.92), indicating that the K(trans) can be reliably assessed clinically. All intracranial aneurysms had a pronounced increase in wall permeability compared with the paired healthy MCA (P < .001). Regression analysis demonstrated a significant trend toward an increased K(trans) with increasing aneurysm size (P < .001). Logistic regression showed that K(trans) also predicted risk in anatomic (P = .02) and combined anatomic/clinical (P = .03) groups independent of size. CONCLUSIONS: We report the first evidence of dynamic contrast-enhanced MR imaging-modeled contrast permeability in intracranial aneurysms. We found that contrast agent permeability across the aneurysm wall correlated significantly with both aneurysm size and size-independent anatomic risk factors. In addition, K(trans) was a significant and size-independent predictor of morphologically and clinically defined high-risk aneurysms.

Predictors of hemorrhage volume and disability after perimesencephalic subarachnoid hemorrhage.

OBJECTIVE: The determinants of subarachnoid hemorrhage (SAH) volume and an atypical pattern of blood are not clear. Our objective was to determine if reduced platelet activity on admission and abnormal venous drainage are associated with greater SAH volume. METHODS: We prospectively identified noncomatose patients with SAH without an identifiable aneurysm. We routinely measured platelet activity on admission and recorded aspirin use. SAH volumes were calculated with a validated technique. CT angiograms were reviewed by a certified neuroradiologist for venous drainage. Patients were followed for clinical outcomes through 3 months with the modified Rankin Scale (mRS). Data are Q1-Q3. RESULTS: There were 31 patients in the cohort. Thirty (97%) underwent an angiogram on admission, and 25 (81%) an additional delayed angiogram. SAH volume was lowest with normal venous drainage bilaterally (4.4 [3.7-16.4] mL) and higher with 1 (12.9 [3.7-20.4]) or 2 (20.9 [12.5-34.6] mL, p = 0.03) discontinuous venous drainages. Patients with reduced platelet activity had more SAH on the diagnostic CT (17.5 [10.6-20.9] vs 6.1 [2.3-15.3] mL) (p = 0.046). SAH volume was greater for patients requiring drainage for hydrocephalus (16.4 [11.5-20.5] vs 5.4 [2.7-16.4] mL) (p = 0.009). Outcomes at 3 months were generally excellent (median mRS = 0, no symptoms). CONCLUSIONS: Discontinuous venous drainage and reduced platelet activity were associated with increased SAH volume and hydrocephalus. These factors may explain thick SAH and reduce the need for repeated invasive imaging in such patients.

Spinal arteriovenous malformations associated with Klippel-Trenaunay-Weber syndrome: a literature search and report of two cases.

SUMMARY: Patients with Klippel-Trenaunay-Weber syndrome present with venous varices, cutaneous capillary malformations, and tissue hypertrophy, usually involving an extremity. A small but important subset also harbors arteriovenous malformations (AVMs) of the spine. We report 2 such cases, 1 with 3 concurrent spinal arteriovenous fistulas. These cases and our review of the literature emphasize the importance of screening the spine for AVMs. In addition, it is also important to investigate for the presence of multiple spinal AVMs.

Acute physiological derangement is associated with early radiographic cerebral infarction after subarachnoid haemorrhage.

BACKGROUND: Cerebral infarction after aneurysmal subarachnoid haemorrhage (SAH) is presumed to be due to cerebral vasospasm, defined as arterial lumen narrowing from days 3 to 14. METHODS: We reviewed the computed tomography scans of 103 patients with aneurysmal SAH for radiographic cerebral infarction and controlled for other predictors of outcome. A blinded neuroradiologist reviewed the angiograms. Cerebral infarction from vasospasm was judged to be unlikely if it was visible on computed tomography within 2 calendar days of SAH or if angiography showed no vasospasm in a referable vessel, or both. RESULTS: Cerebral infarction occurred in 29 (28%) of 103 patients with SAH. 18 patients had cerebral infarction that was unlikely to be due to vasospasm because it was visible on computed tomography by day 2 (6 (33%)) or because angiography showed no vasospasm in a referable artery (7 (39%)), or both (5 (28%)). In a multivariate model, cerebral infarction was significantly related to World Federation of Neurologic Surgeons grade (odds ratio (OR) 1.5/grade, 95% confidence interval (CI) 1.1 to 2.01, p = 0.006) and SAH-Physiologic Derangement Score (PDS) >2 (OR 3.7, 95% CI 1.4 to 9.8, p = 0.01) on admission. Global cerebral oedema (OR 4.3, 95% CI 1.5 to 12.5, p = 0.007) predicted cerebral infarction. Patients with cerebral infarction detectable by day 2 had a higher SAH-PDS than patients with later cerebral infarction (p = 0.025). CONCLUSIONS: Many cerebral infarctions after SAH are unlikely to be caused by vasospasm because they occur too soon after SAH or because angiography shows no vasospasm in a referable artery, or both. Physiological derangement and cerebral oedema may be worthwhile targets for intervention to decrease the occurrence and clinical impact of cerebral infarction after SAH.

Third nerve paresis caused by vascular compression by the posterior communicating artery.

OBJECTIVE AND IMPORTANCE: Third nerve paresis frequently occurs because of external compression by an internal carotid-posterior communicating artery aneurysm. We report 1 case of third nerve palsy because of direct vascular compression by the posterior communicating artery. CLINICAL PRESENTATION: A 69-year-old man presented to the hospital with the sudden onset of left third nerve palsy and a history of chronic headaches. A cerebral angiogram showed a cavernous aneurysm of the left internal carotid artery as well as a large dilatation of the left posterior communicating artery. INTERVENTION: A left transylvian approach exposed an infundibulum of the left posterior communicating artery in contact with and creating an indentation on the third cranial nerve. The artery was dissected free of the nerve, and vascular decompression was achieved with complete resolution of the oculomotor nerve paresis. CONCLUSION: Third nerve palsy may in some cases result from direct vascular compression by the posterior communicating artery, particularly if associated with a broad infundibulum.

Treatment decisions in brain AVMs: the case for and against surgery.

Thus, it is clear that intracranial AVMs are a complex and heterogeneous condition, as are the patients they afflict. There is no true single strategy that is successful in even a majority of patients. The process of evaluation and management of AVM patients is a very strong argument for the creation of a "stroke center" in which a multidisciplinary team of cerebrovascular practitioners interacts collegially and effectively on a day-to-day basis for the management of the gamut of ischemic and hemorrhagic stroke problems.

Failure of a saphenous vein extracranial-intracranial bypass graft to protect against bilateral middle cerebral artery ischemia after carotid artery occlusion: case report.

OBJECTIVE AND IMPORTANCE: We present the case of a patient who experienced bilateral middle cerebral artery infarctions after Hunterian ligation and trapping of a ruptured right cavernous aneurysm, despite a high-flow extracranial-intracranial bypass. This is a rare complication, and it highlights the need for further refinements in our understanding of the hemodynamic insufficiency created by major vessel sacrifice. CLINICAL PRESENTATION: The patient was a 59-year-old woman who experienced multiple episodes of massive epistaxis before undergoing angiography, which revealed left internal carotid artery occlusion and an irregular right cavernous aneurysm. The patient was then transferred to our center for treatment. The patient was neurologically intact at presentation, and her epistaxis was controlled by nasal packing. INTERVENTION: The patient underwent an extracranial-intracranial bypass from the external carotid artery to the M2 segment of the right middle cerebral artery, followed by trapping of the aneurysm. Despite evidence of graft patency, the patient experienced bilateral middle cerebral artery distribution infarctions after surgery. CONCLUSION: Although extracranial-intracranial bypasses protect the majority of patients who undergo carotid artery ligation from ischemic complications, this case demonstrates that hemodynamic insufficiency can occur even with a high-flow saphenous vein graft. Better ways to quantitate the hemodynamic needs of the brain after major vessel sacrifice may facilitate matching of the revascularization strategy to the specific needs of each patient, thus further reducing the likelihood of ischemic complications.

Current results of the surgical management of aneurysms of the basilar apex.

OBJECTIVE: To provide current information regarding the expected clinical outcomes and sources of morbidity and mortality in the modern surgical management of basilar apex aneurysms. METHOD: A retrospective review was conducted of 303 cases of such aneurysms that were treated surgically during 18 years at one institution. Postoperative angiography was performed in 81% of the cases. Clinical grading using the Glasgow Outcome Scale was conducted at the time of hospital discharge and for 91% of the surviving patients at 6 months after surgery. The preoperative parameters that were linked statistically to poor clinical outcome were identified through the use of single and multivariate analyses. RESULTS: More than 80% of the patients were operated on using some modification of the trans-sylvian exposure, and temporary arterial occlusion was used routinely. Good outcomes (Glasgow Outcome Scale scores of 4 or 5) were achieved in 76% of the patients at the time of discharge and in 81% of the patients at 6 months after surgery. There was no incidence of postoperative subarachnoid hemorrhage. Residual aneurysm was revealed by postoperative angiography in 6% of the cases. Factors found to be statistically linked to poor outcome included poor admission grade (Hunt and Hess Grades IV and V), patient age older than 65 years, computed tomographic demonstration of thick basal cistern clot, aneurysm size greater than 20 mm, and symptoms attributable to brain stem compression. CONCLUSION: Direct microsurgical repair of basilar apex aneurysms should result in good clinical outcomes in 80 to 85% of cases, with reliable prevention of subarachnoid bleeding and routine elimination/reduction of symptoms secondary to mass effect. Those patients who are at high risk for poor outcomes can be identified by the presence of certain clinical, radiographic, and demographic features before undergoing surgery and can be considered for alternative or adjunctive modes of therapy if long-term efficacy of such treatment is demonstrated.

Resection of a large arteriovenous fistula of the brain using low-flow deep hypothermic cardiopulmonary bypass: technical case report.

OBJECTIVE AND IMPORTANCE: We present the second report in the literature on the use of low-flow hypothermic cardiopulmonary bypass to aide in the surgical resection of a large intraparenchymal arteriovenous fistula. CLINICAL PRESENTATION: The patient was a 46-year-old man who was found to have a left sylvian arteriovenous fistula with a giant varix during a workup for chronic left frontal headaches and was referred to our center for management. A cardiac workup revealed a cardiac output of 9 L per minute. INTERVENTION: Endovascular embolization of the lesion was initially attempted without success because of the high flow within the lesion and the large diameter of the feeding arteries. We then planned combined and staged endovascular and surgical approaches to gradually eliminate the fistula. Endovascular embolization, both transarterial and transvenous, could not be performed because of the high flow in the fistula. Despite the stepwise reduction of flow during the course of several weeks via surgical exposures and arterial ligations, the fistula remained difficult to remove because of its size and the turgor of the varix. Once hypothermic low-flow circulatory bypass was used, however, decompression of the sac allowed access to the afferent vasculature. CONCLUSION: The use of low-flow hypothermic circulatory bypass can facilitate the surgical extirpation of certain large intraparenchymal arteriovenous fistulas.

Posteroinferior cerebellar artery aneurysms: surgical results for 38 patients.

OBJECTIVE: Posteroinferior cerebellar artery aneurysms have an incidence of approximately 0.49%. Reports in the literature are sparse concerning outcomes in this patient population. We report our results for 38 consecutive patients who were treated during the last 6.5 years. METHODS: All patients (n = 38) with posteroinferior cerebellar artery aneurysms that were surgically treated at Zale-Lipshy University Hospital between January 1990 and May 1997 were retrospectively reviewed. Data were collected and analyzed relating to demographics, condition at presentation, lesion characteristics, associated medical problems, postsurgical complications, and outcome. RESULTS: Sixty-six percent of the patients (n = 25) experienced neurological sequelae, which included symptomatic vasospasm, hydrocephalus, dysarthria, paresis, diplopia, ataxia, and facial paralysis. Many, however, showed significant improvement during their hospitalization and during the course of the ensuing year. Seventy-four percent of the patients had a Glasgow Outcome Scale score of 1 or 2 at the time of discharge, 91% at 6 months after surgery, and 89% at 1 year after surgery. CONCLUSION: This review summarizes the presentations and outcomes of 38 consecutive surgical cases during a 6.5-year period and concludes that posteroinferior cerebellar artery aneurysms are not benign entities. The study does, however, also demonstrate that patients have significant recuperative potential after the treatment of these lesions.

The history of neurological surgery at Northwestern University.

The residency program in neurological surgery at Northwestern University was founded in 1924 by Loyal Davis and was formally accredited by the American Board of Neurological Surgery in 1946. Allen Kanavel, mentor to Davis, was one of the original members of the Society of Neurological Surgeons. Five individuals have served as chief of neurosurgery at Northwestern: Davis, Paul Bucy, Anthony Raimondi, Albert Butler, and H. Hunt Batjer. Davis was the first surgeon west of the Appalachians to limit his work to neurosurgery. Between 1954 and 1963, there were two independent neurosurgery residency programs at Northwestern, one headed by Davis and the other by Bucy. A master surgeon and superb teacher, Bucy trained more than 65 residents and became one of the greatest authors and leaders in the field of neurosurgery. Neurosurgical training at Northwestern has traditionally emphasized excellence of patient care, strong resident and student teaching, and basic science research. Through the years, a major strength of the program has been its clinical volume and diversity. Four hospitals have played major roles in the program: Northwestern Memorial Hospital (created by the merger of Chicago Wesley Memorial Hospital and Passavant Memorial Hospital), Children's Memorial Hospital, Evanston Hospital, and the Veterans Administration Lakeside Hospital. This article traces the development of neurological surgery at Northwestern, with an emphasis on its historical background and the contributions of Kanavel, Davis, and Bucy. The present philosophy and structure of the training program and the program's future under the direction of Batier are also described.

Intraoperative aneurysm rupture and complication avoidance.

The unexpected rupture of an intracranial aneurysm is a potentially catastrophic event. Strategies to control intraoperative aneurysm hemorrhage are based on sound surgical principles and take into consideration such variables as the timing, location, and severity of the rupture. Proven, successful techniques to prevent or control complications during aneurysm surgery are discussed in this article.