A 6-fr guiding catheter (slim guide(®)) for use with multiple microdevices. An experimental study.

A modified technique is required in patients with wide-necked aneurysms whose treatment by the single microcatheter technique is difficult. We developed a 6-Fr guiding catheter (Slim Guide(®)) that features a large lumen (0.072 inch) for performing the modified technique. To evaluate the usefulness of Slim Guide(®) we carried out experiments using three types of 6-Fr guiding catheter. In experiment 1, the shaft hardness and kink resistance were compared among three different guiding catheters (Slim Guide(®), Launcher(®), Envoy(®)). In experiment 2, we inserted a microballoon catheter and a microcatheter into the three different guiding catheters and recorded the maximal infusion pressure. In experiment 3, we inserted 13 different types of microdevices into the three different guiding catheters and evaluated the resistance of the microdevices. Although the shaft of the Slim Guide(®) was softer than that of the other two guiding catheters, its kink resistance was comparable. The maximal infusion pressure was significantly lower than with Launcher(®) or Envoy(®) catheters. Furthermore, with Slim Guide(®), in 136 of 143 microdevice combinations examined (95.1%) there was no resistance; this was true for 125 (87.4%) and 116 (81.1%) combinations using the Launcher(®) - and the Envoy(®) guiding catheters, respectively. There was a significant difference between Slim Guide(®) and the other two guiding catheters with respect to their accommodation of double microsystems (p<0.05). Although the inner diameter of Slim Guide(®) is slightly larger than of the other two guiding catheters, it significantly increased the combination of microdevices that could be used for the coil embolization of difficult aneurysms.

Evaluation of dural arteriovenous fistulas with 4D contrast-enhanced MR angiography at 3T.

BACKGROUND AND PURPOSE: Four-dimensional contrast-enhanced MR angiography (4D-CE-MRA) at 3T may replace digital subtraction angiography (DSA) for certain diagnostic purposes in patients with intracranial dural arteriovenous fistula (DAVF). The aim of this study was to test the hypothesis that 4D-CE-MRA at 3T enables the same characterization of intracranial DAVFs as DSA. MATERIALS AND METHODS: The study population consisted of 18 consecutive patients with intracranial DAVFs (11 women, 7 men; age range, 35-82 years; mean age, 64.8 years). They underwent 4D-CE-MRA at 3T and DSA. The 4D-CE-MRA series combined randomly segmented central k-space ordering, keyhole imaging, sensitivity encoding, and half-Fourier imaging. We obtained 30 dynamic scans every 1.9 seconds with a spatial resolution of 1 x 1 x 1.5 mm. Two independent readers reviewed the 4D-CE-MRA images for main arterial feeders, fistula site, and venous drainage. Interobserver and intermodality agreement was assessed by kappa statistics. RESULTS: At DSA, 8 fistulas were located at the transverse sigmoid sinus; 8, at the cavernous sinus; and 2, at the sinus adjacent to the foramen magnum. Interobserver agreement was fair for the main arterial feeders (kappa = 0.59), excellent for the fistula site (kappa = 0.91), and good for venous drainage (kappa = 0.86). Intermodality agreement was moderate for the main arterial feeders (kappa = 0.68) and excellent for the fistula site (kappa = 1.0) and venous drainage (kappa = 1.0). CONCLUSIONS: The agreement between 4D-CE-MRA and DSA findings was good to excellent with respect to the fistula site and venous drainage.

Assessment of vascular supply of hypervascular extra-axial brain tumors with 3T MR regional perfusion imaging.

BACKGROUND AND PURPOSE: The vascular supply of extra-axial brain tumors provided by the external carotid artery has not been studied with RPI. The purpose of this work was to determine whether RPI assessment is feasible and provides information on the vascular supply of hypervascular extra-axial brain tumors. MATERIALS AND METHODS: Conventional ASL and RPI studies were performed at 3T in 8 consecutive patients with meningioma. On the basis of MRA results, we performed RPI by placing a selective labeling slab over the external carotid artery. Five patients underwent DSA before surgery. Two neuroradiologists independently evaluated the overall image quality, the degree of tumor perfusion, and the extent of the tumor vascular territory on conventional ASL and RPI. RESULTS: In overall quality of conventional ASL and RPI, no images interfered with interpretation. In comparisons of the vascular tumor territory identified by the conventional ASL and RPI techniques, the territories coincided in 3 cases, were partially different in 4, and completely different in 1. The interobserver agreement was very good (kappa = 0.82). In 5 patients who underwent DSA, the 4 patients in whom the dominant supply was the external carotid artery were scored as coincided or partially different. The 1 patient in whom the vascular supply was from the internal carotid artery was scored as completely different. CONCLUSIONS: RPI with selective labeling of the external carotid artery is feasible and may provide information about the vascular supply of hypervascular extra-axial brain tumors.

Possible involvement of the M2 anti-inflammatory macrophage phenotype in growth of human gliomas.

Within tumours, many non-neoplastic cells such as fibroblasts, endothelial cells, and macrophages assist tumour growth by producing various growth factors and pro-angiogenic cytokines. Various tumour-derived molecules drive tumour-associated macrophages towards an anti-inflammatory phenotype (M2) and thus promoting tumour growth. Here we investigated microglia/macrophage differentiation in glioma tissues by means of immunostaining of paraffin-embedded glioma samples. The number of microglia/macrophages with positive staining for CD163 and CD204, which are believed to be markers for M2 macrophages, was correlated with the histological grade of the gliomas. The ratio of M2 macrophages in the tumour-associated microglia/macrophages was also associated with the histological grade. Culture supernatant from the glioma cell line can stimulate macrophages to develop into the M2 phenotype in vitro. Macrophage colony-stimulating factor (M-CSF), which strongly induces M2 polarization of macrophages, was significantly correlated with histological malignancy and with the proportion of M2 microglia/macrophages in vivo. In addition, the proportion of M2 microglia/macrophages and M-CSF expression in tumour cells correlated well with proliferation of glioblastoma cells. These results suggest that tumour-derived M-CSF induces a shift of microglia/macrophages towards the M2 phenotype, which influences tumour growth. Evaluation of the proportion of M2 microglia/macrophages and M-CSF expression in tumour tissue would be useful for assessment of microglia/macrophage proliferative activity and the prognosis of patients with gliomas.

Prognostic value of perfusion MR imaging of high-grade astrocytomas: long-term follow-up study.

BACKGROUND AND PURPOSE: Although the prognostic value of perfusion MR imaging in various gliomas has been investigated, that in high-grade astrocytomas alone has not been fully evaluated. The purpose of this study was to evaluate retrospectively whether the tumor maximum relative cerebral blood volume (rCBV) on pretreatment perfusion MR imaging is of prognostic value in patients with high-grade astrocytoma. MATERIALS AND METHODS: Between January 1999 and December 2002, 49 patients (30 men, 19 women; age range, 23-76 years) with supratentorial high-grade astrocytoma underwent MR imaging before the inception of treatment. The patient age, sex, symptom duration, neurologic function, mental status, Karnofsky Performance Scale, extent of surgery, histopathologic diagnosis, tumor component enhancement, and maximum rCBV were assessed to identify factors affecting survival. Kaplan-Meier survival curves, the logrank test, and the multivariate Cox proportional hazards model were used to evaluate prognostic factors. RESULTS: The maximum rCBV was significantly higher in the 31 patients with glioblastoma multiforme than in the 18 with anaplastic astrocytoma (P < .03). The 2-year overall survival rate was 67% for 27 patients with a low (< or =2.3) and 9% for 22 patients with a high (>2.3) maximum rCBV value (P < .001). Independent important prognostic factors were the histologic diagnosis (hazard ratio = 9.707; 95% confidence interval (CI), 3.163-29.788), maximum rCBV (4.739; 95% CI, 1.950-11.518), extent of surgery (2.692; 95% CI, 1.196-6.061), and sex (2.632; 95% CI, 1.153-6.010). CONCLUSION: The maximum rCBV at pretreatment perfusion MR imaging is a useful clinical prognostic biomarker for survival in patients with high-grade astrocytoma.

Magnetic resonance imaging of pilocytic astrocytomas: usefulness of the minimum apparent diffusion coefficient (ADC) value for differentiation from high-grade gliomas.

BACKGROUND: On contrast-enhanced magnetic resonance (MR) images, pilocytic astrocytomas (PAs) are usually well-enhanced tumors that may mimic high-grade gliomas (HGGs). On the other hand, it has been suggested that areas exhibiting minimum apparent diffusion coefficient (ADC) values reflect the sites of highest cellularity within heterogeneous tumors. PURPOSE: To test the hypothesis that the cellularity of PAs is significantly different to the cellularity of HGGs, which should result in significant differences in minimum ADC values. MATERIAL AND METHODS: Between 1999 and 2005, 15 patients (nine males, six females) with histopathologically confirmed PAs underwent pretreatment MR examination including diffusion-weighted (DW) imaging. We reviewed their MR findings with respect to the size, location, morphology, contrast enhancement, and minimum ADC value of the tumors. The minimum ADC values of the 15 PAs were compared with those of 104 HGGs diagnosed during the same period. RESULTS: The diameter of the 15 PAs ranged from 11 to 60 mm (mean 36 mm); all were located around the ventricles, and all contained enhancing components. All except two small (11 and 14 mm) PAs contained cystic components. The minimum ADC values were significantly higher in PAs (median 1.688, range 1.375-1.897 x 10(-3) mm(2)/s) than HGGs (0.997, 0.543-2.024 x 10(-3) mm(2)/s) (P < 0.0001), although there was substantial overlap. Among the tumors with enhancing components, all but one PA were differentiated from the 76 HGGs with enhancing components (0.922, 0.543-1.462 x 10(-3) mm(2)/s) when the minimum ADC cutoff value was set at 1.5 x 10(-3) mm(2)/s. CONCLUSION: The minimum ADC value may be helpful for the differentiation between PAs and HGGs. A tumor with enhancing components should be PA instead of HGG when the minimum ADC value is higher than 1.5 x 10(-3) mm(2)/s.

Effect of bilateral subthalamic nucleus stimulation on levodopa-unresponsive axial symptoms in Parkinson's disease.

BACKGROUND: The levodopa responsiveness of motor, particularly axial symptoms is a good predictor of the effectiveness of subthalamic nucleus (STN) stimulation in patients with Parkinson's disease (PD). However, many Japanese PD patients are intolerant of higher doses of antiparkinsonian drugs and some aspects of their axial symptoms may remain unresponsive to treatment. We retrospectively investigated the effects of bilateral STN stimulation on the axial signs unresponsive to levodopa in Japanese patients with PD. METHODS: We enrolled 29 consecutive patients into this study. Six independent axial symptoms, i.e. falling, freezing, gait, standing, posture, and postural instability, were scored on the Unified Parkinson's Disease Rating Scale (UPDRS), before and 3 months after bilateral STN stimulation and differences were statistically analysed. FINDINGS: Postoperatively, the mean levodopa dosage was decreased by 27%. The preoperative responsiveness to antiparkinsonian drugs with respect to freezing, gait, posture, and postural instability were positively correlated with postoperative off-medication improvement (p < 0.05). For each individual axial symptom, some patients showed an excellent response to STN stimulation, despite preoperative unresponsiveness to levodopa. These selected patients were not always treated with lower doses of antiparkinsonian drugs preoperatively, but they had milder preoperative scores on the UPDRS with respect to daily activities and overall axial function. CONCLUSIONS: The axial symptoms of PD unresponsive to levodopa were ameliorated by bilateral STN stimulation in patients manifesting a milder degree of preoperative axial signs. Our findings suggest that STN stimulation exerted a definite but limited effect on levodopa-unresponsive axial features, pointing to the need to identify different target structures that control axial functions via non-dopaminergic systems.

Spontaneous resolution of isolated dissecting aneurysm on the posterior inferior cerebellar artery.

The authors report a rare example of an isolated dissecting posterior inferior cerebellar artery (PICA) aneurysm with spontaneous resolution. A 41 year-old male suffered sudden dizziness, nausea and vomiting. An angiogram and magnetic resonance imaging (MRI) detected an isolated PICA dissection. The patient was treated conservatively and recovered without any apparent neurological deficit. MRI detected the self-resolution of the dissecting aneurysm. Dissecting PICA aneurysms, especially non-haemorrhagic lesions, have the possibility of spontaneous resolution resulting in a favorable outcome. The treatment strategy for this vascular lesion may be decided based upon neuroradiological changes on careful follow-up.

Differentiation between paraclinoid and cavernous sinus aneurysms with contrast-enhanced 3D constructive interference in steady- state MR imaging.

BACKGROUND AND PURPOSE: Differentiation between paraclinoid and cavernous sinus aneurysms of the internal carotid artery (ICA) is critical when considering treatment options. The purpose of this study was to determine whether contrast-enhanced (CE) 3D constructive interference in steady state (CISS) MR imaging is useful to differentiate between paraclinoid and cavernous sinus aneurysms. MATERIALS AND METHODS: This study included 11 aneurysms in 10 consecutive female patients, ranging from 52 to 66 years of age. All aneurysms were adjacent to the anterior clinoid process. After conventional and CE 3D-CISS imaging on a 1.5T MR imaging unit, all patients underwent surgery, and the relationship between the aneurysms and the dura was confirmed. Two neuroradiologists evaluated the location of the aneurysms on CE 3D-CISS images and classified them as intradural, partially intradural, and extradural aneurysms. Operative findings were used as a reference standard. To understand the imaging characteristics, we assessed the boundary and signal intensity of the cavernous sinus, CSF, and carotid artery on the side contralateral to the lesion. RESULTS: Operative findings disclosed that 5 aneurysms were intradural and 6 were extradural. All except 2 were accurately assessed with CE 3D-CISS imaging. One intradural aneurysm adjacent to a large cavernous aneurysm and 1 cavernous giant aneurysm were assessed as partially intradural. On CE 3D-CISS images, the boundary between the CSF, cavernous sinus, and carotid artery was identified by high signal-intensity contrast in all cases. CONCLUSION: CE 3D-CISS MR imaging is useful for the differentiation between paraclinoid and cavernous sinus aneurysms.

Predictive assessment of shunt effectiveness in patients with idiopathic normal pressure hydrocephalus by determining regional cerebral blood flow on 3D stereotactic surface projections.

BACKGROUND: The regional cerebral blood flow (rCBF) and cerebral metabolism in patients with idiopathic normal pressure hydrocephalus (iNPH) remain to be studied in detail. PURPOSE: Using single-photon emission computed tomography (SPECT), we compared the characteristic rCBF patterns in iNPH patients who did, or did not, respond to shunt operations. MATERIALS AND METHODS: We studied 24 consecutive iNPH patients: 14 men and 10 women aged 68 to 88 years (mean 77.5 years). Using the Japanese normal pressure hydrocephalus grading scale, they were divided into responders and non-responders to shunt operations. Follow-up ranged from 10 to 36 months (mean 25 months). We obtained baseline single-photon emission computed tomography (SPECT) data on three-dimensional stereotactic surface projections (3D-SSP) before and after shunt operations, and compared rCBF in responders and non-responders. RESULTS: On statistical maps, responders manifested significantly lower rCBF in the basal frontal lobes and cingulate gyrus (anterior-dominant). CONCLUSIONS: The preoperative measurement of rCBF by 3D-SSP SPECT may help to identify iNHP patients expected to exhibit a good response to shunt operations.

Multiple peripheral middle cerebral artery aneurysms associated with Behcet's disease.

We report a 19-year-old woman with Behcet's disease who suffered a subarachnoid hemorrhage and had bilateral peripheral middle cerebral artery aneurysms. After steroid therapy for 3 days, the smaller aneurysm disappeared. The larger aneurysm was excised and the artery reconstructed using a superficial temporary artery graft. Histological examination showed vasculitis restricted to the wall of the aneurysm. This is the first report of arterial reconstruction for an aneurysm associated with Behcet's disease. Steroid therapy before the operation may facilitate repair of the arterial wall.

Multiple prominent dilated perivascular spaces do not induce Wallerian degeneration as evaluated by diffusion tensor imaging.

It is unknown whether dilated perivascular spaces can affect the adjacent neuronal fibers. We describe conventional MR and diffusion tensor imaging findings of a case with multiple, prominent dilated perivascular spaces in the left cerebral hemisphere. Diffusion tensor imaging showed no alterations in the fractional anisotropy and apparent diffusion coefficient values for the corona radiata, posterior rim of the internal capsule, and the cerebral peduncle, indicating no wallerian degeneration associated with dilated perivascular spaces.

Pediatric primary CNS lymphoma: longterm survival after treatment with radiation monotherapy.

Primary central nervous system lymphoma (PCNSL) in childhood is very rare. We report a 5-year-old boy who presented with headache and nausea. Magnetic resonance imaging (MRI) showed a faintly enhanced lesion in the left cerebellar hemisphere. MRI-guided biopsy was returned with a histopathological diagnosis of lymphoma. Cranial radiotherapy alone with whole-brain irradiation (30 Gy) followed by a 20-Gy booster to the tumor bed was successful and the patient is alive, well, and in persistent complete remission 14 years post-treatment. This is the only pediatric PCNSL encountered at our institution between 1989 and 2004.

External Manual Carotid Compression is Effective in Patients with Cavernous Sinus Dural Arteriovenous Fistulae.

SUMMARY: External manual carotid compression is a non-invasive method to treat patients with cavernous sinus dural arteriovenous fistulae (CSDAVF). We studied a group of patients with CSDAVF to identify factors that made cure by compression therapy possible. We treated 23 patients with CS-DAVF without cortical venous drainage or a recent decline in visual acuity by compression therapy. All were followed up by magnetic resonance angiography (MRA) at one, three, six, and 12 months after treatment and the characteristics of the imaging findings, their neurological symptoms, and the patterns of symptom improvement were examined. In group A (n=8), cure was achieved by manual carotid compression; in the other 15 patients (group B), cure was not obtained. Group B manifested significantly higher ocular pressure and a significantly longer interval between symptom onset and treatment by manual carotid compression. In group A, venous drainage was via the superior orbital vein (SOV) with/without involvement of the inferior petrosal sinus (IPS); closure of the CS-DAVF occurred within 4.1 months after the start of treatment. In three patients symptom improvement progressed steadily and gradually. The other five cured patients experienced transient worsening of their symptoms at two to four months after the start of treatment, these resolved within four to seven months. Manual carotid compression was effective in patients without retrograde venous CS-DAVF drainage or a severe decline in visual acuity. The factors that rendered cure by compression therapy possible were lower ocular pressure and a shorter interval between symptom onset and the start of treatment. Venous drainage in those patients was exclusively via the SOV without involvement of the IPS.

Diffusion-weighted imaging of metastatic brain tumors: comparison with histologic type and tumor cellularity.

BACKGROUND AND PURPOSE: On diffusion-weighted imaging (DWI), metastatic tumors of the brain may exhibit different signal intensities (SI) depending on their histology and cellularity. The purpose of our study was to verify the hypotheses (1) that SI on DWI predict the histology of metastases and (2) that apparent diffusion coefficient (ADC) values reflect tumor cellularity. MATERIALS AND METHODS: We assessed conventional MR images, DWI, and ADC maps of 26 metastatic brain lesions from 26 patients, 13 of whom underwent surgery after the MR examination. Two radiologists performed qualitative assessment by consensus of the SI on DWI in areas corresponding to their enhancing portions. We measured the contrast-to-noise ratio (CNR) on T2-weighted images and normalized ADC (nADC) values, and compared them with tumor cellularity. RESULTS: The mean SI on DWI and the CNR on T2-weighted images were significantly lower in well differentiated than in poorly differentiated adenocarcinomas and lesions other than adenocarcinoma. The mean nADC value was significantly higher in well differentiated than poorly differentiated adenocarcinomas and lesions other than adenocarcinoma. All 3 small-cell carcinomas and 1 large-cell neuroendocrine carcinoma exhibited high SI on DWI. The nADC value showed a significant inverse correlation with tumor cellularity. There was no significant correlation between the CNR and tumor cellularity. CONCLUSION: The SI on DWI may predict the histology of metastases; well differentiated adenocarcinomas tended to be hypointense, and small- and large-cell neuroendocrine carcinomas showed hyperintensity. Their ADC values reflect tumor cellularity.

Clinical evaluation of cellulose porous beads for the therapeutic embolization of meningiomas.

BACKGROUND AND PURPOSE: Cellulose porous beads (CPBs) are a new, exceptionally uniformly sized, nonabsorbable embolic agent. We evaluated their efficacy in the preoperative embolization of meningiomas. METHODS: In 141 consecutive patients, we used CPBs (200-microm diameter) for the preoperative embolization of meningiomas. We selected patients whose tumors were > or =4 cm with 50% of blood to the tumor supplied by the external carotid artery (ECA). All patients underwent a provocation test before embolization. The percentage of blood supplied to the tumor by the internal carotid artery and ECA was determined angiographically. Nonenhanced areas on postembolization MR imaging were calculated. Intraoperative blood loss, units of blood transfusion, and hemostasis at the time of surgery were recorded for each patient. The interval between embolization and surgery was intentionally longer than 7 days. RESULTS: Of the 141 patients, 128 underwent CBP embolization. Eleven patients had positive provocation test results, and 2 had vasospasm; they were not CBP embolized. In 72% of the patients CBP embolization achieved reduction in the flow of the feeding artery by more than 50%. The nonenhanced area on MR imaging was not significantly correlated with the degree of ECA supply or devascularization. The interval between embolization and surgery was 8-26 days (mean, 9.9 days). The longer this interval, the greater was the tumor-softening effect and the rate of tumor removal. CONCLUSIONS: CPBs may be useful for the preoperative embolization of meningiomas. To increase the efficacy of CPB embolization, the interval to surgery should be at least 7 days.

Evaluation of the Stability of Small Ruptured Aneurysms with a Small Neck after Embolization with Guglielmi Detachable Coils. Correlation between Coil Packing Ratio and Coil Compaction.

SUMMARY: It is difficult to predict the compaction of Guglielmi detachable coils (GDC) after endovascular surgery for aneurysms. Therefore, we studied the relationship between the coil packing ratio and compaction in 62 patients with acute ruptured intracranial aneurysms that were small (< 10 mm) had a small neck (< 4 mm) and were coil-embolized with GDC-10. We recorded the maximum prospective coil length, L, as the length that correspond with the volume of packed coils occupying 30% of the aneurysmal volume. L was calculated as L (cm) = 0.3 x a x b x c and the coil packing ratio expressed as packed coil length/L x 100, where a, b, and c are the aneurysmal height, length, and width in mm, respectively. Angiographic followup studies were performed at three months and one and two years after endovascular surgery. Of the 62 patients, 16 (25.8%) manifested angiographic coil compaction (ten minor and six major compactions); the mean coil packing ratio was 51.9 +/- 13.4%. The mean coil packing ratio in the other 46 patients was 80.5 +/- 20.2% and the difference was statistically significant (p < 0.01). In all six patients with major compaction the mean packing ratio was below 50%. We detected 93.8% of the compactions within 24 months of coil placement. In patients with small, necked aneurysms, the optimal coil packing ratio could be identified with the formula 0.3 x a x b x c. The probability of compaction was significantly higher when the coil packing ratio was under 50%. To detect coil compaction post-embolization, follow-up angiograms must be examined regularly for at least 24 months.

Serial changes in the regional cerebral blood flow of patients with hypertensive intracerebral hemorrhage -- long-term follow-up SPECT study.

We analyzed serial changes in the regional cerebral blood flow (rCBF) of 13 patients with intracerebral hemorrhage by single photon emission computed tomography (SPECT) during the acute- to chronic stage (2 hr to 55 weeks). The (99m)Tc-ethyl cysteinate dimmer ((99m)Tc-ECD) was used as the nuclear mediator. The SPECT timing within 48 hours after the onset was considered to be acute stage, from 48 hours to 4 weeks to be subacute stage, and after 4 weeks to be chronic stage. The region of interest was each hemisphere in the whole brain without ventricles at the thalamic level. For semi-quantitative analysis of rCBF, we used the Brain Uptake Ratio method. Of the 13 patients (mean age 65.5 years), 3 had thalamic-, 4 putaminal-, 5 subcortical-, and one a cerebellar hemorrhage; the hematoma volume varied from 4-50 ml (<20 ml, n=9; 20-30 ml, n=1; >30 ml, n=3; mean 17 ml). The rCBF changes during the long-term follow-up were classified as increase-, decrease-, and unchanged type. Of 5 patients with increased rCBF, 4 made a good recovery and one was severely disabled; of 5 patients with decreased rCBF, 1 made a good recovery, 3 were moderately-, and one was severely disabled. All 3 patients with unchanged rCBF were moderately disabled. Our findings suggest that among patients with hypertensive intracerebral hemorrhage, those with increased rCBF over time may have a favorable outcome. We further need more cases with intracerebral hemorrhage to clarify this trend.

Clinico-pathological study of meningiomas with haemorrhagic onset.

BACKGROUND: Haemorrhage from meningiomas is rare and the underlying pathophysiological mechanisms remain to be determined. We sought to identify these mechanisms by studying clinical and histological records of 6 meningioma patients treated at our institution. PATIENTS AND METHODS: We retrospectively studied 6 patients with meningiomas whose acute onset was due to haemorrhage. We evaluated clinical features and imaging studies. The vascularity and proliferative nature of these tumours were examined immunohistochemically and tissue factor (TF) immunoreactivity was assessed. For comparison we evaluated 25 non-haemorrhagic meningiomas. FINDINGS: At onset, the haemorrhages mimicked stroke in all 6 patients. On imaging studies, 3 of the haemorrhages were intra- and extratumoural, the other 3 were extratumoural only. Hyperintensity on T2-weighted MRI was a characteristic of these meningiomas. Histologically, they were of 3 subtypes, meningothelial (n=3), transitional (n=2), and anaplastic (n=1). The MIB-1 labelling index of the 5 WHO Grade I meningiomas was 5.8+/-2.2. The mean number of CD31-positive blood vessels did not differ in haemorrhagic and non-haemorrhagic meningiomas. The TF-positivity rate of haemorrhagic meningiomas was higher than of non-haemorrhagic meningiomas. INTERPRETATION: The proliferative nature of the meningiomas and TF expression in tumour cells may have contributed to the eventual haemorrhage of the meningiomas in our series.

Hydroxyapatite and bFGF Coating of Detachable Coils for Endovascular Occlusion of Experimental Aneurysm.

SUMMARY: The purpose of this study was to evaluate the effect of hydroxyapatite (HAp) and fibroblast growth factor-basic (bFGF) coating on Guglielmi detachable coils (GDCs) in an experimental aneurysm model. A total of 18 aneurysms were experimentally made in the common carotid arteries of swine. Embolization was done on these aneurysms using standard GDCs and coated GDCs with HAp (GDC-HAp) and with bFGF (GDC-HAp-bFGF). The animals were then killed 14 days after embolization. The development of tissue scarring and coverage the aneurysm's orifice were evaluated macroscopically. No significant difference of volume ratio of the coils exited in each groups. Macroscopically, covering ratio of fibrous membrane at the neck of aneurysms were 88.3 +/- 14.7% in a group with GDC-HAp-bFGF, while it were 26.7 +/- 15.3% in a group with standard GDC and it was 41.7 +/- 31.7% in a group with GDC-HAp. These results indicated that coating by hydroxyapatite and bFGF might facilitate a wound healing in an experimental aneurysm model.