Identification of Vortex Cores in Cerebral Aneurysms on 4D Flow MRI.

BACKGROUND AND PURPOSE: The complexity and instability of the vortex flow in aneurysms are factors related to the rupture risk of unruptured cerebral aneurysms. We identified aneurysm vortex cores on 4D flow MR imaging and examined the relationship of these factors with the characteristics of cerebral aneurysms. MATERIALS AND METHODS: We subjected 40 aneurysms (37 unruptured, 3 ruptured) to 4D flow MR imaging. We visualized streamlines with velocities below the threshold-that is, a percentage value of the aneurysm maximum inflow velocity-and progressively decreased the threshold to identify vortex cores as thin, streamline bundles with minimum velocities. Complexity and stability were compared in aneurysms with a smooth surface and those with blebs or daughter sacs. RESULTS: The threshold for visualizing vortex cores ranged from 3% to 13% of the maximum inflow velocity. Vortex cores could be visualized in 38 aneurysms; in 2, they were not visualized through the cardiac cycle. A simple flow pattern (single vortex core) was identified in 27 aneurysms; the other 13 exhibited a complex flow pattern. The cores were stable in 32 and unstable in 8 aneurysms. Significantly more aneurysms with-than-without blebs or daughter sacs had a complex flow pattern (P = .006). Of the 3 ruptured aneurysms, 1 aneurysm had an unstable vortex core; in the other 2, the vortex core was not visualized. CONCLUSIONS: The identification of vortex cores on 4D flow MR imaging may help to stratify the rupture risk of unruptured cerebral aneurysms.

Inflow Jet Patterns of Unruptured Cerebral Aneurysms Based on the Flow Velocity in the Parent Artery: Evaluation Using 4D Flow MRI.

BACKGROUND AND PURPOSE: Inflow jet characteristics may be related to aneurysmal bleb formation and rupture. We investigated the visualization threshold on the basis of the flow velocity in the parent artery to classify the inflow jet patterns observed on 4D flow MR imaging. MATERIALS AND METHODS: Fifty-seven unruptured aneurysms (24 bifurcation and 33 sidewall aneurysms) were subjected to 4D flow MR imaging to visualize inflow streamline bundles whose velocity exceeded visualization thresholds corresponding to 60%, 75%, and 90% of the maximum flow velocity in the parent artery. The shape of the streamline bundle was determined visually, and the inflow jet patterns were classified as concentrated, diffuse, neck-limited, and unvisualized. RESULTS: At the 75% threshold, bifurcation aneurysms exhibited a concentrated inflow jet pattern at the highest rate. At this threshold, the inflow jets were concentrated in 13 aneurysms (group C, 22.8%), diffuse in 18 (group D, 31.6%), neck-limited in 11 (group N, 19.3%), and unvisualized in 15 (group U, 26.3%). In 16 (28.1%) of the 57 aneurysms, the inflow jet pattern was different at various thresholds. Most inflow parameters, including the maximum inflow velocity and rate, the inflow velocity ratio, and the inflow rate ratio, were significantly higher in groups C and D than in groups N and U. CONCLUSIONS: The inflow jet pattern may depend on the threshold applied to visualize the inflow streamlines on 4D flow MR imaging. For the classification of the inflow jet patterns on 4D flow MR imaging, the 75% threshold may be optimal among the 3 thresholds corresponding to 60%, 75%, and 90% of the maximum flow velocity in the parent artery.

The Preventive Effect of Endovascular Treatment for Recurrent Hemorrhage in Patients with Spinal Cord Arteriovenous Malformations.

BACKGROUND AND PURPOSE: Spinal cord AVMs represent rare and insufficiently studied pathologic entities. Embolization is thought to play an important role in the management of spinal cord AVMs. Factors for recurrent hemorrhage and the impact of endovascular treatment on prevention of recurrent hemorrhage remain to be confirmed. We aimed to assess recurrent hemorrhagic incidence of spinal cord AVMs and its prevention by endovascular treatment. MATERIALS AND METHODS: We reviewed 80 patients with spinal cord AVMs by spinal cord angiography who had hemorrhage before the first endovascular treatment at New York University Medical Center, Beth Israel Medical Center, or Roosevelt Hospital in New York. We compared the baseline and radiologic characteristics of patients with and without recurrent hemorrhage by the log-rank test and the Cox proportional hazards model. RESULTS: We observed recurrent hemorrhage in 35 (44%) patients (1/41 patients with endovascular treatment and 34/39 patients without endovascular treatment). The median length of total follow-up was 659 days (interquartile range, 129-2640 days), and the median length from first-to-recurrent hemorrhage was 369 days (interquartile range, 30-1596 days). The log-rank test revealed that endovascular treatment and venous thrombosis reduced recurrent hemorrhage, and associated aneurysm was related to recurrent hemorrhage. Even in multivariate analysis, the endovascular treatment reduced (hazard ratio, 0.027; P < .0001) and associated aneurysm increased (hazard ratio, 3.4; P = .044) the risk of recurrent hemorrhage. CONCLUSIONS: Endovascular embolization is the first choice of treatment for spinal cord AVMs and is effective in preventing recurrent hemorrhage.

Parent artery curvature influences inflow zone location of unruptured sidewall internal carotid artery aneurysms.

BACKGROUND AND PURPOSE: Future aneurysmal behaviors or treatment outcomes of cerebral aneurysms may be related to the hemodynamics around the inflow zone. Here we investigated the influence of parent artery curvature on the inflow zone location of unruptured sidewall internal carotid artery aneurysms. MATERIALS AND METHODS: In 32 aneurysms, the inflow zone location was decided by 4D flow MR imaging, and the radius of the parent artery curvature was measured in 2D on an en face image of the section plane corresponding to the aneurysm orifice. RESULTS: The inflow zone was on the distal neck in 10 (group 1, 31.3%), on the lateral side in 19 (group 2, 59.4%), and on the proximal neck in 3 (group 3, 9.4%) aneurysms. The radius in group 1 was significantly larger than that in group 2 (8.3 mm [4.5 mm] versus 4.5 mm [1.9 mm]; median [interquartile range]; P < .0001). All 7 aneurysms with a radius of >8.0 mm were in group 1. All 18 aneurysms with a radius of <6.0 mm were in group 2 or 3. In two group 3 aneurysms, the inflow zone was located in a part of the neck extending beyond the central axis of the parent artery. CONCLUSIONS: The inflow zone locations of sidewall aneurysms can be influenced by the parent artery curvature evaluated in 2D on an en face image of the section plane corresponding to the aneurysm orifice.

Visualization of angiographical arteriovenous shunting in perisylvian glioblastomas.

BACKGROUND: Arteriovenous shunting visualized by angiography is one of the major features of glioblastomas, and the visualization is dependent on the presence of extensive shunting. Extensive arteriovenous shunting is associated with the risk of poorly controlled intraoperative bleeding. When a tumor with extensive arteriovenous shunting is located in close proximity to the eloquent regions of the brain, a meticulous surgical procedure is necessary. In the present study, the site-oriented visualization of angiographical arteriovenous shunting was evaluated from the perspective of surgical treatment, with a particular focus on the perisylvian region that is in close proximity to motor and language regions (dominant hemisphere), as well as large arteries and veins. METHODS: Twenty-six consecutive patients underwent a resection of glioblastoma between February 2007 and September 2012. All patients were presurgically examined using digital subtraction angiography. The patients were subdivided into the following two groups based on the location of the tumor: 1) perisylvian glioblastoma (18 patients) and 2) non-perisylvian glioblastoma (eight patients). Angiography to detect the arteriovenous shunting was performed. In addition, the number of intratumoral vessels, tumor proliferative activity (MIB-1 labeling index), and volume of intraoperative bleeding were evaluated and compared between the two groups. RESULTS: Angiographical arteriovenous shunting was definitively visualized in 13 of 18 (72 %) perisylvian glioblastomas, in contrast to only one of eight (13 %) non-perisylvian glioblastomas (p = 0.007). There were no significant differences between the two groups with respect to the number of intratumoral vessels, MIB-1 labeling index, and volume of intraoperative bleeding. However, massive intraoperative bleeding of > 2,000 mL occurred in one perisylvian glioblastoma patient. CONCLUSIONS: Glioblastomas in the perisylvian region tend to be associated with extensive arteriovenous shunting that can be definitively visualized by performing an angiography. Because arteriovenous shunting carries the risk of intraoperative bleeding, perisylvian glioblastomas-particularly in the dominant hemisphere-should be resected with a meticulous surgical procedure and strategy.

Spinal arteriovenous metameric syndrome: clinical manifestations and endovascular management.

BACKGROUND AND PURPOSE: SAMS is a rare form of SCAVM. We discuss the clinical presentation, endovascular management, and outcome of this disease in our series. MATERIALS AND METHODS: Retrospective review was performed in patients with SCAVM and SAMS who underwent angiography with intent to treat at our institution from 1980 to 2010. RESULTS: One hundred forty-eight SCAVMs were identified, and 28 (19%) of these were SAMS. Of these 28 patients, 24 had nidus-type AVMs and 4 had fistulas. SAMS were more prevalent in females (71% versus 48%), and also presented earlier than non-SAMS SCAVMs. Intradural hemorrhage (SAH or hematomyelia) was the most common presentation and more common than in non-SAMS lesions. Twenty-six patients underwent embolization of the intradural lesion in 50 sessions. Thirteen patients underwent treatment of intradural aneurysms in 16 sessions. Six patients underwent embolization of extradural lesions in 16 sessions. Twenty-three patients had an average of 94 months of clinical follow-up (3-309 months) after the first treatment, during which 5 patients had hemorrhages. Angiographic follow-up was performed in 20 patients at an average of 85 months (range, 3-309 months), which showed new development or enlargement of an aneurysm in 5 patients. This type of angiographic progression was more common in patients with SAMS. CONCLUSIONS: SAMS most commonly presents with hemorrhage from the SCAVM. Endovascular embolization can be performed safely with good functional outcome, though most patients clinically deteriorate in the long term. Periodic angiographic follow-up with intent to perform preventive target embolization is important to control the disease.

Adrenal function in patients with community-acquired pneumonia.

Adrenal insufficiency is believed to occur frequently in severe sepsis and septic shock. The aim of the present study was to determine whether adrenal function is also related to the severity of community-acquired pneumonia (CAP). In total, 64 Japanese patients with CAP were consecutively enrolled in the present study, which was carried out during 2005-2006. Serum adrenocorticotropic hormone (ACTH) and cortisol were measured in each subject, as was the response of cortisol secretion when 250 mug of cosyntropin was administered. Analyses were performed comparing these values with the score calculated according to the Pneumonia Patient Outcomes Research Team (PORT) cohort study, the number of in-hospital deaths and the length of hospital stay. As the PORT score increased, serum ACTH and cortisol also increased, while the response of cortisol secretion to the administration of cosyntropin decreased. In the analysis by receiver operating characteristic curves, adrenal dysfunction was related significantly to both the number of in-hospital deaths and the length of hospital stay. Adrenal dysfunction was shown to correlate with the Pneumonia Patient Outcomes Research Team score and the clinical outcomes, while adrenal insufficiency defined by the cosyntropin stimulation test was rare in the present study.

Application of high-intensity focused ultrasound for umbilical artery occlusion in a rabbit model.

OBJECTIVES: To investigate the application of high-intensity focused ultrasound (HIFU) for fetal umbilical artery blood flow occlusion in a rabbit model. METHODS: A prototype HIFU transducer in combination with an imaging probe with Doppler capability was constructed. Using this transducer, HIFU was applied at 1.4, 2.75 or 5.5 kW/cm(2) through the maternal abdominal skin to the fetal intra-abdominal umbilical arteries of four time-mated Japanese White rabbits (11 fetuses) on gestational day 25. Courses of 5-s HIFU exposure were performed until cessation of umbilical blood flow and cardiac arrest were confirmed by Doppler ultrasonography. Fetal necropsy was performed and exposed lesions were assessed by microscopic histological analysis. RESULTS: The mean diameter of the fetal umbilical artery was 0.6 +/- 0.2 mm and the mean peak systolic velocity of arterial blood flow was 44.7 +/- 18.5 cm/s. When HIFU was applied at 5.5 kW/cm(2), blood flow was completely occluded within 15 courses. HIFU exposure brought about vacuolar degeneration and destruction of elastic fibers in the tunica media of the artery. CONCLUSIONS: HIFU can be used to occlude umbilical artery blood flow in fetal rabbits.

Endovascular treatment of multiple severe atherosclerotic stenoses with cerebral hypoperfusion. Case report.

SUMMARY: A 60-year-old man presented with syncope and transient left-sided motor weakness. Cerebral angiography revealed multiple severe atherosclerotic stenoses of bilateral internal carotid arteries, bilateral intracranial vertebral artery (VA), and left VA origin. A SPECT study showed poor cerebral perfusion and vascular reserve in the right cerebral hemisphere and the posterior circulation.We performed angioplasty and stentings for the VA stenoses first by using balloon-expandable stents. The patient had shown no syncope attack ever since, which might be due to an increased vascular reserve in the posterior circulation. The following bilateral carotid angioplasty and stentings could be performed safely. Angioplasty and stenting is feasible, and can improve cerebral perfusion even in a patient with multiple severe atherosclerotic stenoses by pre-operative appropriate haemodynamic assessment.

An in vitro interethnic comparison of monoamine oxidase activities between Japanese and Caucasian livers using rizatriptan, a serotonin receptor 1B/1D agonist, as a model drug.

AIMS: Monoamine oxidase (MAO) is located in human liver, and catalyses the oxidative deamination step of many xenobiotics. However, whether there exists an interethnic difference in MAO activities has, to our knowledge, not been clarified. We aimed to assess the MAO type A (MAO-A) involvement in the metabolic pathway of rizatriptan (RIZ), an antimigraine 5-hydroxytryptamine (5-HT)1B/1D agonist, and the interethnic difference in MAO activities between Caucasians and Japanese using RIZ as a model drug in in vitro experiments. METHODS: Oxidative deaminase activities were determined with the subcellular fractions of Japanese livers and the microsomal fraction of Caucasian livers using RIZ, 5-HT (MAO-A substrate) and 2-phenylethylamine (PEA) (MAO-B substrate) as substrates. RESULTS: The oxidative deaminase activities of RIZ vs. 5-HT were highly (r = 0.87 and 0.96, P < 0.001) correlated with each other in both the microsomal and mitochondrial fractions of Japanese livers. Subsequent results were obtained from in vitro experiments using liver microsomes based upon these findings. The oxidative deaminase activities of RIZ were inhibited completely by the nanomolar-order concentration of clorgyline and Ro 41-1049 (MAO-A selective inhibitors), but not by that of Ro 16-6491 (MAO-B selective inhibitor). The majority of the mean Michaelis-Menten values for three substrates toward MAO obtained from six Japanese and six Caucasian liver microsomes reached no significant differences between the two ethnic groups. The mean microsomal oxidative deaminase activities assessed in 18 Japanese and 20 Caucasian livers using the three substrates also showed no significant differences between the two ethnic groups. CONCLUSIONS: RIZ is mainly metabolized by MAO-A and the in vitro oxidative deaminase activities mediated via MAO-A and -B do not appear to differ between Japanese and Caucasians.

[The efficacy of switch therapy in community-acquired pneumonia in Japan].

To evaluate the efficacy of Switch therapy for community-acquired pneumonia, we conducted a prospective randomized controlled study in thirty-two hospitalized patients. These cases corresponded to Fine's risk classes II to IV. Using a table of random numbers, sixteen patients were assigned to a Switch therapy group, and the other sixteen, to a clinical pathway group. Both groups initially received intravenous antimicrobials. Within the Switch therapy group, when all the patients were afebrile for more than sixteen hours, their intravenous antimicrobials were switched to oral, and the patients were discharged on the following day. For all patients in the clinical pathway group, the critical pathway was defined as an eight-day planned hospitalization, with a time-task matrix formatted for disease treatment, laboratory testing, physical examination, oxygen saturation monitoring, ambulation, diet, patient education and clinical outcome. Switch therapy reduced the period of intravenous antimicrobial administration from 7.6 days to 4.0 days (p < 0.0001). The period required to switch to oral antimicrobials decreased from 8.3 days to 4.8 days (p < 0.0001); hospital stay length, from 9.8 days to 6.5 days (p = 0.0001); and medical resource utilization, from 330, 373 to 227,768 Japanese yen (p = 0.0002). No patient from either group required readmission. In conclusion, Switch therapy was more efficient than management with a clinical pathway for mild to moderate community-acquired pneumonia in hospitalized patients.

Plasma endothelin, nitric oxide and atrial natriuretic peptide levels in humans after abdominal angiography.

PURPOSE: To clarify the effect of the contrast medium iopamidol on endothelial function and response of vasoactive peptide, as measured by changes in the levels of plasma endothelin, nitric oxide and atrial natriuretic peptide. MATERIAL AND METHODS: Thirteen patients received iopamidol 300 mg I/ml intra-arterially during routine abdominal angiography. The mean volume of contrast medium administered was 208.1+/-32.5 ml. Endothelin, nitric oxide and atrial natriuretic peptide were measured before and after angiography. RESULTS: Endothelin levels increased significantly (from 1.45+/-0.12 pg/ml to 1.90+/-0.10 pg/ml) after exposure to contrast medium. Nitric oxide levels decreased significantly (from 34.56+/-2.23 micromol/ to 25.43+/-1.83 micromol/l). Atrial natriuretic peptide levels increased significantly (from 11.43+/-1.68 pg/ml to 21.28+/-2.89 pg/ml). CONCLUSION: Exposure to contrast medium in humans is associated with an increase in plasma endothelin levels and a decrease in nitric oxide levels, and atrial natriuretic peptide levels also increase following CM injection.

Prevention of evaporation of small-volume sample solutions for capillary electrophoresis using a mineral-oil overlay.

The suppression of evaporation of water from small volumes of sample solutions or reagents for capillary electrophoresis by the use of a mineral-oil overlay was investigated in affinophoresis applications, in which the affinity constant of a mutant protein of recombinant human galectin-1 to a lactose affinophore, a triply negative charged ion having a lactoside as an affinity ligand, was determined. When an injection was carried out from a minimum of 20 microL of an aqueous solution beneath the oil overlay, no oil contamination inside the capillary was observed, provided the capillary was cleanly cut so that the end was flat, and the polyimide coating had been removed for a distance of about 2 mm from the end. Affinophoresis was carried out using 20 microL of an affinophore solution covered with an oil overlay. The abnormalities in the electropherograms as the result of the evaporation of the water from the solution during storage prior to use in an automatic operation of a capillary electrophoresis instrument were suppressed, with respect to the formation of a base line gap, an increase in the detection time of a marker ion and an increase in the initial current. A solution in a vial could be used repeatedly for a longer period of time when overlaid with mineral oil than in the absence of an overlay. The use of a mineral-oil overlay is a simple but very efficient technique for solving the problem of the evaporation of water from small volumes of aqueous solutions for use in capillary electrophoresis.

CT during selective arteriography: anatomical assessment of unruptured intracranial aneurysms before endovascular treatment.

Our aim was to investigate the usefulness of helical CT during selective angiography (CT arteriography) in pretreatment assessment of unruptured intracranial aneurysms. We studied 47 unruptured aneurysms in 34 prospectively recruited patients for whom endovascular embolisation was initially considered. As pretreatment assessment, we performed rotational digital subtraction angiography (DSA) followed by CT arteriography. The findings on axial source images (axial images) and reconstructed three-dimensional CT angiography (3D-CTA) of CT arteriography were compared to those of rotational DSA, with particular attention to the neck of the aneurysm and arterial branches adjacent to it. Information provided by CT arteriography was more useful than that of rotational DSA as regards the neck in 25 (53%) of 47 cases and as regards branches in 18 (49%) of 37 aneurysms. On axial images, small arteries such as the anterior choroidal artery were seen in some cases. CT arteriography can provide valuable additional information about unruptured aneurysms, which cannot be obtained by rotational DSA alone. This technique is useful for obtaining anatomical information about aneurysm anatomy and for deciding the therapeutic strategy.

Improved cerebral perfusion and metabolism after stenting for basilar artery stenosis: technical case report.

OBJECTIVE: Recent advances in stent technology have allowed the introduction of more flexible stents that may be tracked more easily in the intracranial vessels. We present a patient with improved cerebral blood flow and metabolism as assessed by positron emission tomography after stent-assisted angioplasty for symptomatic basilar artery stenosis. CLINICAL PRESENTATION: A 62-year-old man, who had undergone left superficial temporal artery to middle cerebral artery bypass surgery for left internal carotid artery occlusion 10 years previously, presented with dizziness, blurred vision, and memory disturbance. Angiography revealed severe stenosis of the proximal basilar artery. Positron emission tomographic scans revealed decreased cerebral blood flow associated with increased oxygen extraction fraction in the entire brain, particularly in the posterior circulation and the left middle cerebral artery territory. Despite medical treatment, the patient experienced worsening visual disturbance and right-sided motor weakness. INTERVENTION: Ticlopidine and aspirin were used as antiplatelet agents. In addition, we used argatroban, which is a direct thrombin inhibitor, as an anticoagulant during the procedure. Predilation with a coronary artery balloon was performed, followed by placement of a GFX 3- by 8-mm stent (Arterial Vascular Engineering, Santa Rosa, CA), with excellent angiographic results. The patient made a good neurological recovery, and the postoperative positron emission tomographic scan demonstrated increases in both cerebral blood flow and cerebral metabolic rate of oxygen with a normalization of oxygen extraction fraction. CONCLUSION: Stent-assisted angioplasty can provide a favorable clinical course as well as improved cerebral perfusion and metabolism for a patient with basilar artery stenosis. Long-term follow-up data and additional clinical experience are required to assess the durability of this approach.

[Usefulness of multiphase helical CT in the diagnosis of pituitary microadenoma].

The purpose of this study was to determine the value of multiphase helical CT (MHCT) in the diagnosis of pituitary microadenoma. Twenty-two patients with clinically suspected microadenoma were examined. Coronal pre-contrast CT was initially carried out. Three series of helical scanning using 1-mm collimation, 1-mm/s table speed, and 1-mm interval reconstruction covering the entire pituitary gland were performed with an intravenous injection of contrast medium. Immediately after MHCT, delayed CECT was performed. Twenty microadenomas (3-10 mm, mean: 5.5 mm) were surgically confirmed. MHCT could depict all 20 tumors, while pre-contrast CT and delayed CECT showed 4 and 12 of 20 tumors, respectively. MHCT was useful in the diagnosis of pituitary microadenoma owing to its high spatial resolution and extensive coverage.

Radiographic features of invasive lobular carcinoma of the breast.

PURPOSE: To evaluate the radiographic features of invasive lobular carcinoma of the breast. METHODS: We evaluated the radiographic features of 61 cases of histopathologically documented invasive lobular carcinoma. Mammography was performed in all cases. In seven of 61 cases, helical CT with contrast medium was also carried out. Mammographic findings were analyzed to determine true-positive and false-negative rates for the detection of neoplasm. Further, the diameter of the tumor as determined on mammography and helical CT was noted for comparison with the pathologic size. RESULTS: Mammographic features were divided into six types: spiculated mass (38%), indistinct mass (5%), obscured mass (23%), asymmetric opacity (16%), architectural distortion (16%), and no findings (2%). Microcalcifications were present in 12 cases (20%). The overall sensitivity rate was 59%. However, 20 (56%) of 36 cases that were diagnosed as detectable on mammography were underestimated in terms of tumor size compared with the histopathologic findings. Four cases examined by helical CT with contrast medium were compared with the histopathologic findings in terms of extent of the lesion. In three cases, helical CT was more precise than mammography, but the histopathologic findings showed lesions beyond the region evaluated by helical CT. CONCLUSION: Invasive lobular carcinoma is difficult to detect radiographically, and the extent of the lesion tends to be underestimated.

[A case of giant cell tumor originating from the rib].

We have experienced a case of giant cell tumor originating from the rib. A 45-year-old male was admitted to our hospital because of a mass in the left chest wall. A tumor shadow was observed in the left side of chest X ray. Chest CT, bone scintigram showed tumor originating from the left 4th rib. The tumor was suspected giant cell tumor of bone by needle biopsy examination. The tumor was completely resected with chest wall surrounding the tumor. The defect of chest wall was reconstructed with Marlex mesh and the Latissimus dorsi muscle flap. The pathological diagnosis was a giant cell tumor of bone. The patient has been well for two years and one month since surgery, with no signs of recurrence.

Paramedian supracerebellar transtentorial approach for a medial tentorial meningioma with supratentorial extension: technical case report.

OBJECTIVE AND IMPORTANCE: The choice of surgical approach to treat medial tentorial meningiomas is crucial and sometimes difficult to make. Although the subtemporal approach is most commonly used for lesions that extend mostly supratentorially, it risks injury to the vein of Labbé or the veins coursing along the subtemporal surface. To avoid venous injury, a medial tentorial meningioma was removed transtentorially through the infratentorial space via the paramedian supracerebellar transtentorial (PSCTT) approach. CLINICAL PRESENTATION: A 35-year-old right-handed woman presented with a generalized convulsion. Magnetic resonance imaging scans revealed a left medial tentorial meningioma with supratentorial extension at the dominant hemisphere. The main venous drainage route from the ipsilateral temporal lobe was a sphenopetrosal vein. INTERVENTION: An operation was performed with the patient in a sitting position, and the tumor was resected totally via the paramedian supracerebellar transtentorial approach without perioperative complications. CONCLUSION: The paramedian supracerebellar transtentorial approach is useful for supratentorially located medial tentorial meningiomas without retraction of the temporal lobe and without damage to the vein of Labbé or the sphenopetrosal vein.

Ruptured irregularly shaped aneurysms: pseudoaneurysm formation in a thrombus located at the rupture site.

OBJECT: The authors describe the clinical, radiological, and pathological findings of ruptured cerebral aneurysms with irregular configurations. METHODS: Eight patients with subarachnoid hemorrhage due to ruptured irregularly shaped aneurysms were examined. The preoperative radiological findings in these cases were compared with the pathological and operative findings of endovascular or open surgery. All of the aneurysms exhibited delayed opacification and delayed washout of contrast medium from the irregularly shaped portion of the aneurysm on digital subtraction angiography and/or helical computerized tomography scanning. Endovascular embolization with platinum coils was attempted in the first four patients who underwent treatment. In three of these patients the aneurysm ruptured again during the endovascular procedure. In the fourth patient an intraaneurysm thrombus was observed during the procedure and clipping was performed. In the subsequent four patients, three underwent clipping without complication and one underwent partial aneurysm embolization because of poor general status. A thrombus adjacent to the aneurysm dome was observed in the patients who underwent open surgery. Pathological examination of the operative specimens revealed a pseudoaneurysm-like cavity in the thrombus that was adherent to the aneurysm. CONCLUSIONS: Ruptured irregularly shaped aneurysms may be accompanied by fragile pseudoaneurysm-like cavities located at the rupture point. Because these aneurysms have a high risk of repeated rupture during an endovascular procedure, advancing microinstruments to the weaker portion of the aneurysm should be avoided.