Interventional Neuroradiology

Basilar artery (BA) fenestrations are the most frequently observed variant of the cerebral arteries. We examined the magnetic resonance (MR) angiographic incidence, location, characteristic configuration of BA fenestration and associated vascular disease.

From April 2004 to September 2004, a total of 2280 cranial MR angiographies were performed at our institution. Twenty-three BA fenestrations (1.0%) were detected on MRA. There were 13 males and ten females in this group and mean age was 57.6 years old. Three cases of these fenestration group are suffered with atherothrombic infarction in the territory of vertebro-basilar system. Seven of 23 cases (30%) were associated with intracranial aneurysm. Of those four cases, aneurysms were located at anterior circulation. Of those three cases, the aneurysms were associated with BA fenestration. Since saccular aneurysms are reported to arise frequently at BA fenestration, knowledge and recognition of fenestration are useful and important in the interpretation of cerebral MR angiography.

A follow-up of the embolized cerebral aneurysm with Guglielmi Detachable Coils (GDC) were performed mainly using craniograms and digital subtraction angiograms (DSA) so far. Recently, several authors have reported about efficacy of the time of flight (TOF) magnetic resonance angiogram (MRA) as a follow-up for the embolized cerebral aneurysms. In our institution, 3-D reconstructed TOF MRAs have been performed as a follow-up of the embolized cerebral aneurysms. We examined efficacy of 3-D reconstructed TOF MRA.

3-D TOF MRA was performed for a follow-up of the embolized cerebral aneurysms at our outpatient clinic in 35 patients. Morphological examination of the 3-D images between 3-D TOF MRA and 3-D DSA was performed.

Almost similar images of 3-D MRA were obtained after 3-D reconstruction as compared with those of 3-D DSA. In three cases, recanalization was suspected in the 3-D TOF MRA. And recanalization was confirmed in the 3-D DSA actually.

A quality of 3-D TOF MRA for a diagnosis of recanalization was good and practical. However, in two cases, arteries were partially disappeared in the 3-D TOF MRA. These were the artifact due to coil mass and this is a current limitation of 3-D TOF MRA.

The images of 3-D TOF MRA that were reconstructed in the 3-D workstation were very similar to those of 3-D DSA. 3-D reconstructed TOF MRA was very useful for a less-invasive diagnosis of a recanalization of the embolized cerebral aneurysms.

Intra-aneurysmal flow dynamics is analyzed qualitatively and quantitatively with numerical simulation technique, and presented for the future clinical application in embolizing cerebral aneurysms. From the volumetric data obtained by three-dimensional computed tomographic angiography, patient-specific vessel models were created for 16 middle cerebral artery aneurysms. Intra-aneurysmal flow dynamics was visualized and analyzed qualitatively, and the geometrical parameters of vessels and aneurysms that affect the intra-aneurysmal flow dynamics were determined quantitatively by correlation analysis. The flow velocity was delayed in the aneurysm cavity, especially at its tip where the rupture usually occurs.

The intra-aneurysmal flow dynamics was considerably influenced by the geometrical parameters that are related to the width of the neck and the branching angle of larger branch artery. The intra-aneurysmal flow dynamics is complex, and the numerical flow simulations with patient-specific vascular models seems effective in understanding the flow dynamics and planning the endovascular treatment of cerebral aneurysms.

Ruptured saccular aneurysms were severe condition for intracerebral Condition. And the cause for their rupture is not yet clear. In this study (I), since the configurations of aneurysms are considered to be a factor for the rupture of aneurysms, several shapes has been modeled using

Aspect ratio AR and inclination angle of saccular aneurysms. In vitro the parametric study has been conducted on the range of Reynolds Number in human blood flow for aneurismal models of AR=2.1 and 1.3 and q =90° and 70°, As results, it was con firme d that there are characteristic flow patterns with Reynolds Number, And that the aneurismal configuration has effects on the shear stress and pressure losses. II) The object of this paper is to study the effects of STENTS. We made the model of aneurysm and performed in vitro study in range of Reynolds number of human blood flows using three kinds of STENTS. As results, it was confirmed that flow pattern and pressure loss changes with the kinds of STENTS. This study aims the accumulation of data to predict the hazard of aneurysmal rupture by their shapes and STENTS.

We developed a rabbit saccular aneurysm model for coil embolization training. Elastase-induced aneurysms were created successfully in about 80% of the rabbits.

The aneurysms were usually broad in the neck and lengthy. At the 28^th postoperative day, the aneurysms were about 1.5 times larger in both width and height than they had been at the 14^th day. All aneurysms were successfully embolized with 18-sized electrically detachable (ED) platinum coils. After embolization, almost all aneurysms had a neck remnant. In conclusion, this model is useful not only for learning the technique of coil embolization but also for testing new embolic materials. The rabbit aneurysm model proved to be an efficacious training modality for endovascular coil embolization.

The aim of this paper is to provide a review of our experience in using the endovascular treatment of ruptured anterior communicating artery (ACoA) aneurysms. Between March 1997 and May 2004, 211 ruptured aneurysms were treated with Guglielmi detachable coil (GDC) system in Mito Medical Center, 73 were located at the ACoA. Two cases were incomplete embolization, and performed microsurgical clipping. In the initial embolization for the 71 aneurysms, complete occlusion was achieved in 44 aneurysms, neck remnant in 11 aneurysms and body filling in 16 aneurysms. Intra-operative complication was occurred in six cases (8.2%).

Aneurysm perforation was occurred in three cases (4.1%), thromboembolic complication was occurred in three cases (4.1%). Acute rebleeding were observed in two cases (2.7%). Endovascular treatment is an effective technique for treating ACoA aneurysms, and 3D-rotational angiography is important diagnostic tool for evaluating the ACoA complex.

The report of the International Subarachnoid Aneurysm Trial (ISAT) study showed that coil embolization was superior to neck clipping as a treatment for subarachnoid haemorrhage (SAH) ¹. We compared the results of coil embolization and neck clipping in our institute. Generally better outcomes were obtained by endovascular surgery than neck clipping. Symptomatic vasospasm and symptomatic hydrocephalus occurred less frequently in coil embolization than neck clipping.

Because not all cases of SAH can be treated by coil embolization due to the width of aneurysmal neck and relation of the aneurysm to parent arteries, we should also be able to perform neck clipping as another modality.

In the 150 endovascular performed cases from May 1997 to Dec 2004, supplemental combination of endovascular and surgical treatments were performed in 46 cases. Characteristics of the treatments were combination for multiple aneurysms, surgical clipping for failed endovascular attempt, embolization for recurrence after clipping, bypass surgery before endovascular parent artery occlusion, surgery for recurrent aneurysms after embolization, and embolization for failed surgical attempt. Sixty seven percent of ruptured and 87% of unruptured cases showed satisfactory clinical outcome (modified Rankin scale = 0 to 2). Supplemental combination of each treatment will support the disadvantage of another treatment, and which improve the clinical outcome of cerebral aneurysm.

We retrospectively analysed to demonstrate the selection of the treatment modality and its efficacy in our department. Subjects of the present study comprised patients in whom coil embolization was abandoned due to such reasons as broad neck, whom coil embolization was performed for residual aneurysm following incomplete clipping or recurrent cerebral aneurysm, whom coil embolization was performed after coil compaction, whom coil embolization and clipping were performed for the treatment of multiple cerebral aneurysms.

In the treatment of cerebral aneurysm, selecting proper techniques by considering the characteristics of clipping and coil embolization is desirable.

In other words, strategizing therapy by taking advantages of the merits of clipping and coil embolization is important.

In this paper, we report five cases with acutely ruptured wide-necked aneurysms, which were treated with coil embolization using a balloon or stent-assisted technique. Balloon-assisted coil embolization using Equinox balloon, Commodore balloon, and Hyperform balloon were performed for four patients and stent-assisted coil embolization using BX velocity for one patient. We discuss problems of coil embolization for acutely ruptured wide-necked aneurysms with a balloon or stent-assisted technique.

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 × a × b × c and the coil packing ratio expressed as packed coil length/L × 100, where a, b, and c are the aneurysmal height, length, and width in mm, respectively. Angiographic follow-up 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 × a × b × 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.

Small ruptured cerebral aneurysms, such as those of 2×3 mm diameter, are considered to be difficult to embolize by detachable coils because of the risk of procedural perforation of the aneurysms. We have treated these small aneurysms and report the techniques and pitfalls of these embolizations. Twenty-four patients with ruptured cerebral aneurysms of 2×3 mm diameter were intended for treatment by coil embolization. Before coil embolization, three-dimensional digital subtraction angiography was performed, and the simulation of the volume embolization ratio (VER) was performed in all patients, except for the first basilar artery aneurysm patient. The tip of the microcatheter was steam-shaped several times and was placed on the neck of the aneurysm. A balloon neck remodeling technique was used for two aneurysms. GDC 10 softs and soft SRs were used for the first ten aneurysms, and Ultrasofts were used for the last eleven aneurysms. Out of twenty-four aneurysm embolizations, we aborted the procedure in three cases, because of a failure in catheterization; we performed clipping surgery for these cases. For the first case of a basilar tip aneurysm, the aneurysm was perforated, due to the use of too long a coil and the insertion of the tip of the microcatheter into the aneurysmal dome. Minor infarction occurred in one patient.

The mean VER was 33.9%, and two aneurysms recanalized, and out of these one needed a second embolization. Six months postoperatively, 81% of patients had made in a good recovery or had a moderate disability. We recommend the following techniques to embolize aneurysms of 2×3 mm diameter: the tip of the microcatheter should be stabilized on the aneurysmal neck by steam shaping of the microcatheter, GDC 10 soft and Ultrasoft should be selected for use, and the simulation of the VER should be performed before embolization to select coils of a suitable length.

We report a series of coil embolizations for small aneurysms solely using GDC ultrasoft coils and discuss the advantages of this method. Seven small aneurysms (<4.0 mm) were embolized solely with ultrasoft coils. Ultrasoft coils were sequentially inserted into aneurysms. Immediately after embolization, five aneurysms were completely occluded, and two exhibited body filling. All cases were treated successfully without any complications. In conclusion, ultrasoft coils were found efficacious for the treatment of small, irregular-shaped, and ruptured aneurysms; their softness and malleability facilitated their compaction into an aneurysm.

Aneurysm embolization using Guglielmi detachable coils(GDC) is gaining acceptance as a viable alternative to surgery in the treatment of cerebral aneurysms. During GDC treatment of cerebral aneurysms, thromboembolic events are the most frequent complications. As risk factors of thromboembolic events, large aneurysms, wide-necked aneurysms, use of the balloon-assisted technique and protruding coils into the parent arteries are previously reported. From March, 1997 till August, 2004, 270 consecutive patients were treated with GDC embolization at our institute. Fourteen (5.2%) patients with 14 aneurysms of these 270 patients presented with protruding coils into the parent vessels.

Twelve aneurysms of these 14 aneurysms were small (diameter <10 mm), and two were large (diameter 15 mm). Nine aneurysms had small necks (neck diameter <4 mm), and five had wide necks(neck diameter >4 mm). The fundus-toneck ratio ranged from 1.04 to 2.78, with an average of 1.53.

In this series, ten patients (71%) were treated with balloon-remodelling technique because every patient had either a wide-necked aneurysm or complicated morphologic factors. These 14 aneurysms were divided into two groups according to the mode of coil protrusion, loop type and tail type protrusion. The first coil was protruded in five (36%) cases of 14 patients, four of these five cases presented with the loop type protrusion. The last coil was protruded in seven cases (50%), Five of these seven cases presented with the tail type protrusion. Diffusion-weighted imaging abnormalities were found for seven (50%) of 14 patients within 24 hours of the coiling procedures. Three (21%) of 14 patients showed small lesions (< 5 mm) in the subcortical white matter at the border zone or perforating regions. In four (29%) patients, large territorial infarctions (>5 mm) were detected. Symptomatic complications occurred in four (29%) patients, and all of these four patients presented the loop type protrusion. One patient who had small infarctions experienced minimal deficits (slight motor weakness, quadrantic hemianopsia) after six days postprocedure and fully recovered by discharge after stronger systemic heparinization (24000U, for three days), aspirin (100 mg/day) and Ticlopidine (100 mg/day). Three patients who had large territorial infarctions experienced moderate deficits.

Two patients were treated with stronger systemic heparinization and one with Argatroban (60 mg/day, for two days), and following aspirin (100 mg/day) and Ticlopidine (100 mg/day). Finally, two patiens were discharged with permanent minimal deficits (hypoesthesia only) and one with moderate hemiparesis. The infarctions related to the GDC procedures were more common sequelae in wide-necked aneurysms and coil protrusions, especially loop type protrusion. Although permanent neurological deficits were rare, the high rate of thromboembolic events associated with coil protrusion suggest that more aggressive medical treatment should be considered.

Thromboembolic events was most important adverse event for coil embolization for intracerebral aneurysm. The present study investigated possible risk factors for thromboembolic events during coil embolization using diffusion-weighted imaging (DWI), comparing unruptured and ruptured lesions.

A 52-year-old male presented with left oculomotor nerve palsy. Angiograms revealed a giant basilar trunk aneurysm with a maximum diameter of 32 mm and a wide neck of 18 mm, located between the superior cerebellar artery and the anterior inferior cerebellar artery and without opacification of posterior communicating arteries. Intra-aneurysmal embolization of the dome was followed by deployment of a 24mm-long coronary balloon-expandable stent across the neck of the aneurysm.

Additional coil embolization of the aneurysmal neck produced good clinical and angiographic results.

We review four cases of posterior cerebral artery (PCA) aneurysm, of which three showed intolerance of parent artery occlusion. In two, balloon test occlusion (BTO) indicated poor opacification of the PCA branches from the anastomoses, and therefore, permanent occlusion was not attempted.

To diagnose VA dissection, MRA or cerebral angiography, which provides information regarding intra-vascular space, has been performed. We report the acquisition of various information about VA dissection using MRI-BPAS, which is a new diagnostic method.

Basi-parallel anatomical scanning (BPAS)-MRI is a simple MRI technique to reveal the surface contour of the intracranial vertebrobasilar artery.

The purpose of this study was to investigate the usefulness of BPAS-MRI for observing the temporal course of unruptured vertebral artery (VA) dissection in patients by means of serial MR examinations. Since April 2003, we performed serial MR examinations in four patients with unruptured acute vertebral artery dissection. The frequency of the MR examinations during the follow-up period in each patient varied from twice within seven months to five times within 19 months. Both MRA and BPAS-MRI were obtained in each MR examination.

We investigated the course of morphological changes within the dissected artery on BPAS-MRI (outer contour) and on MRA (inner lumen).

Although the initial MRA showed fusiform dilatation, irregular stenosis or normal caliber at the dissected lesion, the initial BPAS-MRI disclosed fusiform dilatation in all of the four patients. In two patients, MRA finding of the VA lesion had changed, though the fusiform appearance had been stationary on BPAS-MRI. Then both dissolution of the fusiform dilatation on BPAS-MRI and normalization of the inner luminal caliber on MRA were confirmed within nine months.

In one patient, fusiform dilatation on both BPAS-MRI and MRA resolved simultaneously on the MR examination at eight months after the initial symptom. In another patient, fusiform dilatation of the outer contour was still enlarging on BPAS-MRI ten months after the onset, though the fusiform dilatation on MRA had been stationary since the eighth week. We performed endovascular coil embolization in this patient eleven months after the initial symptom.

Resolution of the fusiform dilatation on BPAS-MRI should be a healing sign of VA dissection. Persisting the fusiform dilatation or progressively enlarging outer contour on BPAS-MRI may be an unstable sign. BPAS-MRI provides more information about the instability of the dissected lesion. We should obtain not only MRA but also BPAS-MRI for the course observation of unruptured VA dissection.

Endovascular surgery is an established primary therapeutic modality for dissecting aneurysms at vertebro-basilar arteries. Intravascular stents can be used to treat the dissecting aneurysms for which simple obliteration procedures cannot be used. In such cases, stent implantation alone or a combination of stents and coils need to be selected properly by taking into consideration the site and shape of dissections.

In this report, three patterns of stent application are described and their method of selection is discussed.

We report a rare case of a ruptured de novo dissecting aneurysm induced by ethyl 2-cyanoacrylate. A 39-year-old woman underwent microvascular decompression for left hemifacial spasm. The offending vessel was left posterior inferior cerebellar artery (PICA). Left vertebral artery (VA) was mobilized and affixed to the dura mater with cyanoacrylate to remove pressure of PICA to the root exit zone of the facial nerve. The left VA was found to be intact at the time of the operation.

One year later, the patient sufferd subarachnoid haemorrhage (SAH) caused by rupture of a newly-developed dissecting aneurysm of the left VA. Endovascular occlusion of the dissecting site was performed using Guglielmi detachable coils. We suppose mechanical injury and chemical reaction of ethyl 2-cyanoacrylate induced dissecting aneurysm.

Polyvinyl alcohol (PVA) particles have been widely used as an embolic material for endovascular treatment of vascular enriched tumors, especially for meningiomas. However, there are disadvantages with their use due to the fact that they are radiolucent, with a very irregular shape and a tendency for self-adhesion. With alternative organic liquids there is also a possibility of toxicity.

We have therefore developed a new embolic material, platinum balls, which feature radioopacity, a relatively well-defined oval shape, multi-pitted and indented surfaces on electron microscopy and a lower tendency for self-adhesion Based on positive findings in experimental studies, embolization of meningiomas was conducted with platinum balls in 27 patients and the results compared with findings for a matched group previously treated with PVA particles. Total volume of blood transfused during surgery was comparable in the two cases, although a tendency for lower values was noted with the platinum balls, and outcome was equally positive.

We have developed a new embolic agent, thermoreversible gelation polymer (TGP). This polymer is unique in that solidification occurs at body temperature. The utility of this new liquid embolic agent for the treatment of large experimental aneurysms was evaluated angiographically.

TGP remains liquid at temperatures below the sol-gel transition temperature (TT) and becomes gelatinous above the TT. TGP can also be used to slowly deliver biologically active substances such as growth factors or engineered cells. In this study, TGP was mixed with radiopaque material without solvent. Bilateral common carotid arteries of swine (n=5) were used for surgical creation of lateral aneurysms, then 1 aneurysm in each animal was embolized using TGP without any protection device. The remaining untreated aneurysm in each animal was used as a control.

All aneurysms were successfully embolized using TGP. No distal migration of TGP was observed when aneurysms were embolized without using protection devices.

TGP can be safely used to embolize experimental aneurysms. Embolization of aneurysms with a protection device needs to be evaluated. Further modifications such as mechanical stability and use as a drug delivery system will be necessary prior to the clinical application of TGP.

To characterize the clinical presentation, imaging features and endovascular treatment of paraspinal non-vertebral arteriovenous fistulas along the segmental nerve.

Retrospective review was performed on the five patients identified in our database covering 1985 to 2003. All patients presented with an incidentally found continuous murmur over the upper paraspinal or parasternal regions before three years old. In four patients, the AV fistula was in the mid-thoracic level and at L3 in one. All AV fistulas were a high-flow single-hole fistula at the neural foramen with venous drainage into paraspinal and epidural veins without intradural reflux. All fistulas were endovascularly occluded in the same session as the diagnostic angiography. The fistula was occluded with detachable coils in one case and with N-butylcyanoacrylate (NBCA) with flow control in four cases. Complete occlusion of the fistula was obtained in all cases and all patients remained neurologically intact at the last follow up (average six years). Non-vertebral paraspinal arteriovenous fistula along the segmental nerve is a specific disease entity seen in children. Embolization is the first choice of treatment for this disease.

Pre-radiosurgical embolization was carried out using cyanoacrylate in seven of 13 patients with cerebral arteriovenous malformations (AVMs) treated by stereotactic radiosurgery (SRS) with a linear accelerator (LINAC). The aim of embolization before SRS was the reduction of AVM volume and/or the elimination of vascular structures bearing an increased risk of haemorrhage. Staged-volume SRS was also performed in two patients because of residual irregular shaped nidus of AVMs even after the embolizations.

Complete obliteration of the AVM nidus on angiogram was presented in five patients with embolizations (including one with staged-volume SRS) and in three of six patients with SRS alone, during follow-up periods after radiosurgery. No patients experienced haemorrhagic events after SRS. Although transient neurological symptoms were observed after embolizations in two patients, no permanent neurological deficits were presented in all patients with SRS. Pre-radiosurgical embolization may allow the effective influence on irradiation therapy in relatively large AVMs and promote more frequent obliteration in more small sized AVMs compared to those with SRS alone. However, further study must be needed to determine whether staged-volume SRS provides a high rate of AVM obliteration and its safeness.

Digital subtraction angiography (DSA) and magnetic resonance imaging (MRI) findings in 20 patients with carotid-cavernous fistula (CCF; 3 direct CCFs and 17 indirect CCFs) were retrospectively reviewed to evaluate venous drainage patterns that may cause intracerebral haemorrhage or venous congestion of the brain parenchyma.

We evaluated the relationship between cortical venous reflux and abnormal signal intensity of the brain parenchyma on MRI. Cortical venous reflux was identified on DSA in 12 of 20 patients (60.0%) into the superficial middle cerebral vein (SMCV; n=4), the uncal vein (n=2), the petrosal vein (n=2), the lateral mesencephalic vein (LMCV; n=1), the anterior pontomesencephalic vein (APMV; n=1), both the APMV and the petrosal vein (n=1) and both the uncal vein and the SMCV (n=1). Features of venous congestion, such as tortuous and engorged veins, focal staining and delayed appearance of the veins, were demonstrated along the region of cortical venous reflux in the venous phase of internal carotid or vertebral arteriography in six of 20 patients (30.0%). These findings were not observed in the eight CCF patients who did not demonstrate cortical venous reflux. MRI revealed abnormal signal intensity of the brain parenchyma along the region with cortical venous reflux in four of 20 indirect CCF patients (20%). Of these four patients, one presented with putaminal haemorrhage, while the other three presented with hyperintensity of the pons, the middle cerebellar peduncle or both on T2-weighted images, reflecting venous congestion. The venous drainage routes were obliterated except for cortical venous reflux in these four patients and the patients without abnormal signal intensity on MRI had other patent venous outlets in addition to cortical venous reflux.

CCF is commonly associated with cortical venous reflux. The obliteration or stenosis of venous drainage routes causes a converging venous outflow that develops into cortical venous reflux and results in venous congestion of the brain parenchyma or intracerebral haemorrhage. Hyperintensity of brain parenchyma along the region of cortical venous reflux on T2-weighted images reflects venous congestion and is the crucial finding that indicates concentration of venous drainage into cortical venous reflux.

Aneurysmal rupture of the intra-cavernous carotid artery may cause idiopathic carotid-cavernous fistula (CCF), and the treatment choice for occluding shunting fistula in this type of CCF is an endovascular approach using detachable balloons. However, little has been reported on treating such lesions with the intra-aneurysmal embolization using Guglielmi detachable coils (GDCs). To our knowledge, ours is the first reported case of successful treatment by selective intra-fistula and intra-aneurysmal embolization with GDCs. A 74-year-old woman exhibited proptosis and chemosis of her left eye over a period of one month. Symptoms of double vision in conversion and pulsatile murmur in her left eye were also noted. Angiography revealed an intra-cavernous aneurysm of the left internal carotid artery (ICA) with a shunting fistula, which drained into the dilated cavernous sinus, superior orbital vein (SOV), superior petrosal sinus, inferior petrosal sinus, and pterygoid plexus. We thought the fistula would occlude by intra-aneurysmal embolization, but we had no confidence of tight packing of the aneurysm since the aneurismal neck was relatively wide. So, we embolized the venous side of the shunting fistula and then the dome of the aneurysm with GDCs. Immediately after the operation, her symptoms and signs were ameliorated, and complete occlusion of the CCF was observed on long-term follow-up. We suggest selective intra-fistula and intra-aneurysmal embolization with GDCs as an alternative method of treatment of idiopathic CCF originating from aneurysmal rupture of the intra-cavernous carotid artery.

We reported the dural AVF case with sinus stenosis, that was entirely treated through the stenting procedure. 61-year-old male had been realizing the attack which causes bilateral visual problem. He would have suffered from the intracranial hypertension caused by dural AVF in the right transverse sinus and left transverse sinus stenosis. We performed TVE and sinus stenting, then used the antiplatelet and the anticoagulant. However, six months later, he suffered from SAH due to recurrence of dural AVF. We performed TVE again, denser packing than usual. Two years later, he have no symptom, angiographically, there was no recurrence of dural AVF and patency of stented sinus.

We think denser embolizations should have performed in case of dural AVF with sinus stenting.

A 40-year-old man was transferred to our hospital due to sudden headache while swimming in the pool. CT revealed cerebellar haematoma within vermis associated with subarachnoid haemorrhage (SAH). Digital subtraction angiography (DSA) showed dural arteriovenous fistulas (DAVFs) with venous pouch on the surface of cerebellar vermis. Fistulas were on the meningeal surface near the sinus confluence. Draining veins formed venous pouch invaginating into cerebellar vermis.

Transarterial embolization (TAE) was performed under the concept that main feeder should be embolized last to occlude the DAVFs completely. Post-embolization 3D-CT showed the cast of N-butyl –cyanoacrylate (NBCA) in the fistulas as well as in the drainer. The good order of occlusion made the embolization complete.

We evaluated Computed Tomography Angiography (CTA) of four different self-expandable stents in phantom model. Three stents ware made of nitinol and one was made of cobalt-based alloy. Each stent placed in plastic injector, filled with diluted iodinated contrast material, and placed on a plastic case filled with saline. CTA was performed on a four-detector CT scanner (detector collimation, 0.5mm: helical pitch 3.5). Axial and longitudinal reconstructions of CT imaging were compared with the in-stent attenuation. Three nitinol stents showed few artifact, and cobalt-based alloy stent was appeared artificial narrowing. In conclusion, CTA is useful for follow-up examination after carotid artery stenting (CAS) as a less invasive evaluation method.

In the safety stenting, it is important to get to know the characteristics of a plaque. In petrous carotid artery stenosis, it is difficult to know the characteristics of the plaque. We paid our attention to the MPRAGE (Magnetization Prepared Rapid Acquisition with Gradient Echo) method on high resolving power MRI.

By the MPRAGE method, low intensity was observed in these lesions of all cases. This result suggested that the plaque in petrous portion was a fibrous plaque. This method is useful to get to know the characteristics of a plaque in petrous portion before endovascular treatment.

Stent implants placed across the neck of cerebral aneurysms are capable of reducing aneurysmal flow when coils are not used for filling the aneurysms. It is important to evaluate the effects of flow reduction caused by stent implants used for the treatment of cerebral aneurysms. Subtracted vortex centers path line method (SVC method) is one of the image post processing methods employed for quantitative flow measurement. We developed a modified SVC method by employing Cinematic Angiography (25 frames/s) and digital video recording (30 frames/s) with a commercial digital camera. We successfully compared the flow effectiveness using a tubular silicon model with a sidewall aneurysm.

The result suggests that our modified SVC method is useful for a comparative examination of the effect of aneurysmal flow reduction caused by stent implants.

Contralateral carotid artery occlusion is thought to represent a significant risk factor in carotid endarterectomy (CEA). There is also evidence that intraoperative and postoperative hypotention may cause contralateral hemodynamic ischemia. As such, contralateral carotid artery occlusion is regarded as a risk factor for carotid angioplasty and stenting (CAS). In this paper, we report on five cases of severe ICA stenosis with contralateral carotid artery occlusions. Cerebral blood flow(CBF) and cerebral vasore-activity(CVR) of the contralateral carotid artery occlusions were measured before and after CAS. Additionally, the influence that ipsilateral CAS exerted on the occluded side was examined.

¹²³I-IMP SPECT was performed before and after CAS, both at rest and at the time of acetazoramide administration. The CBF was evaluated quantitatively using the ARG method. The mean CBF of the treated side rose from 30.0 ± 7.1 ml/100g/min to 34.4 ± 8.3 ml/100g/min (p<0.05), and the mean CBF of the occluded side similarly rose from 28.3 ± 6.1 ml/100g/min to 31.7 ± 6.4 ml/100g/min (p<0.05). Correspondingly, the regional CVR (rCVR) increased from 5.9% ± 16.3% to 35.0% ± 16.4%(p<0.05) on the treated side, and from 3.7% ± 14.7% to 10.7% ± 16.9% (p<0.05) on the occluded side.

This demonstrates that ipsilateral CAS seems to improve both CBF and CVR on the contralateral occluded side. The fact that some cases developed cross flow from the anterior communicating artery was both remarkable and significant. Where there was poor cross flow from the anterior communicating artery, improvement in cerebral vaso reactivity was limited.

This study is performed to investigate risk factors of hypotension in response to elective carotid stenting. Forty-four lesions of 40 consecutive patients (mean age 70.4 ± 8.2 years) were retrospectively analyzed. Easy Wall stent was applied in 15 lesions and SMART stent in 29 lesions. We investigated correlations between the occurrence rate of postoperative hypotension below 90 mmHg and persisting over three hours and findings of preoperative angiograms, ultrasonograms and clinical characteristics. Postprocedural hypotension occurred in 19 patients (47.5%) and medical treatment (intravenous administration of catecholamines) was required in eleven patients (27.5%). Although there was no permanent neurological deficits related with postprocedural hypotension, transient neurological deficits were found in three patients. Risk factors of prolonged postprocedural hypotension were statistically analyzed. On angiographic characteristics; 1) distance between the carotid bifurcation and the lesion with maximum stenosis (≦10 mm vs. >10 mm: p = 0.031), 2) type of stenosis (eccentric vs. concentric: p = 0.014) On ultrasonographic characteristics; 1) calcifications at the carotid bifurcation (present vs. absent: p<0.001). Other variables, including age and degree of stenosis, were not associated with postprocedural hypotension after carotid stenting. These angiographic and ultrasonographic variables can be used to identify patients at risk for postprocedural hypotension after carotid stenting. Such identification may help in selection of patients who will benefit from appropriate pharmacological treatment.

We examined the patients with cervical carotid artery stenosis (>70%) treated by carotid artery angioplasty and stenting (CAS) as a first-choice direct revascularization therapy. The patients consisted of 45 men and seven women; their mean age was 70.4 years (range, 54–84 yr), with 60 cervical carotid stenosis (39 symptomatic and 21 asymptomatic).

Sixty procedures resulted in successful stent deployment in 55 cases, percutaneous transluminal angioplasty (PTA) only without stenting in three, and failed angioplasty due to inaccessibility in two. Morbidity was seen in three cases associated with thromboembolic complication.

Instent restenosis was observed in one case, which was successfully treated with subsequent PTA. CAS seems reasonable treatment for cervical carotid artery stenosis, although further accumulation of the cases will be needed to evaluate the efficacy between CAS and carotid endarterectomy.

Intracranial artery angioplasty utilizing coronary stent is now widely tried as an effective alternative for treating intracranial artery stenosis, and several successful result of stent-assisted angioplasty for intracranial artery were reported.

Authors experienced a case of the basilar artery stenosis, in which re-stenosis progressed rapidly after simple balloon angioplasty and resulted in vessel rupture during stent-assisted angioplasty. Pathological result achieved by autopsy showed vessel wall disruption at the stent and multiple interruptions and defect of elastic laminar.

We describe a case of endo-luminal stent placement with Snare-assist for a cervical internal carotid artery stenosis in which percutaneous access was obtained via the brachial artery.

A 68-year-old man with known disease of the carotid, peripheral, and coronary arteries, with Human T-cell Lymphotrophic Virus type-1 (HTLV-1) Associated Myelopathy (HAM) presented for endoluminal revascularization of a severe, progressive right internal carotid artery stenosis, but with aorto-iliac occlusion.

Transfemoral access was complicated by an aorto-iliac occlusion. A trans-brachial approach was successfully attempted, and a SMARTer stent (Cordis Endovascular, Miami Lakes, FL) was successfully placed through a 7-French Shuttle-SL guide sheath (Cook, Bloomington) under Snare-assist.

The trans-brachial approach is becoming an increasingly viable alternative route for stent placement in patients with contra-indicated or complicated femoral access routes. As devices become increasingly more pliable and smaller, the trans-brachial route will be used with increasing frequency in the select patient population for stenting of both the cervical and intracranial circulation.

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.

Emergency revascularization of acute carotid artery occlusion is still controversial. We treated 15 patients (13 men and two women, mean age of 67.3 years) with acute atherosclerotic carotid occlusion by endovascular procedures and evaluated the usefulness of this treatment. All of the patients were evaluated with emergency MRI and MRA before treatment. Intracranial tandem arterial occlusion due to distal embolism was observed in nine patients, and contralateral carotid stenosis (>70%) was observed in seven. The mean NIHSS score of the patients was 15.4±7.4 (mean±SD) before treatment. Treatment modality included local intraarterial fibrinolysis (LIF), percutaneous transluminal angioplasty (PTA), and carotid artery stenting (CAS). A protective balloon was successfully placed in the distal carotid artery through the plaque before recanalization in seven patients. Three patients were treated with LIF+PTA, five with PTA+CAS, six with LIF+PTA+CAS, and one with PTA only. Successful recanalization of the carotid artery was obtained in 14 of the 15 patients, and distal tandem middle cerebral artery occlusion was also successfully recanalized in eight of the nine patients. GOS was four or five in eight patients (good outcome group) and 1–3 in seven patients (poor outcome group). Mean NIHSS score of the 15 patients was (6.9 ± 7.4) after treatment. Preoperative NIHSS score (10.3 ± 7.4) in the good outcome group was significantly lower than that (21.3 ± 5.4) in the poor outcome group.

The protective balloon technique, PTA with stenting, seems to be useful for acute revascularization of urgent carotid occlusion. Simultaneous treatment of the intracranial tandem occlusive lesion is essential to achieve good clini-cal results. Patients with acute carotid occlusion with NIHSS scores of less than 16 could be good candidates for this advanced treatment.

Balloon Test Occlusion (BTO) is performed to evaluate the collateral flow when a permanent therapeutic occlusion of unilateral carotid artery is planned. BTO with neurological evaluation alone, however, has a rather high false negative rate. In order to improve the sensitivity, several adjunctive procedures such as induced hypotension or cerebral blood flow (CBF) measurement with various modalities have been combined. Perfusion CT (PCT) is another imaging modality that is mainly used for the diagnosis of acute stroke. In this study, we evaluate the efficacy and the safety of BTO combined with PCT in the same procedure utilizing intraarterial contrast injection from the catheter.

Seven patients underwent BTO with PCT in our institution. All the procedures were performed in the angio/CT combination suite. BTO was performed in the usual fashion and when the patient passed the 30 minutes' BTO clinically, PCT was performed subsequently. Contrast material was injected from a Pig Tail catheter placed in the ascending aorta. The obtained data were transferred to a workstation and perfusion maps of CBF, cerebral blood volume (CBV), and time to peak (TTP) were generated using software. In three patients, single photon emission CT (SPECT) was also obtained with administering 99mTc-ethyl cysteinate dimer (99mTc-ECD) intravenously during BTO.

Although all the patients had passed the BTO clinically, the CBF maps of three patients revealed significant decrease in the occluded hemisphere. There was no procedure-related morbidity. PCT using intraarterial contrast injection during BTO was performed successfully and safely. Intraarterial injection allowed us to obtain excellent time-attenuation curves by utilizing less contrast material and less radiation doze.

This study evaluated the clinical usefulness of preoperative embolization of the pial artery or dural branch of the internal carotid artery (ICA) for brain tumor. Subjects comprised 17 patients with large hypervascular brain tumors who underwent preoperative selective embolization. Micro-catheters (2- or 1.7-F) and shapeable hydrophilic micro-guide wires were used for pial artery (branching from the posterior or anterior cerebral artery) or ICA dural branch embolization.

Embolization was performed under digital subtraction fluoroscopy with Polyvinyl alcohol (PVA) particles (150–250 mm) and/or liquid coil. Tumor resection was performed immediately or the day after embolization. Digital subtraction angiography (DSA) before and after endovascular devascularization, blood loss during tumor resection, and clinical outcome were evaluated. All endovascular procedures were technically successful. Post-embolization DSA revealed either a disappearance or a marked decrease of the tumor stain in all cases. Control of intraoperative bleeding was easily accomplished, and intraoperative blood loss was low. Preoperative particle embolization of the feeding artery from the cortical artery or ICA dural branch is safe and effective as adjuvant therapy before tumor resection.

Pitfall during the embolization and evaluation after the embolization for skull base meningiomas supplied by meningeal arteries of internal carotid artery (ICA) are reported. This study includes 15 cases of skull base meningiomas (two males and 13 females) that supplied by meningeal branches of internal carotid artery. The preoperative embolization was performed by these feeders. MRI findings and serum levels of C-reactive protein (CRP) after the embolization were examined. In ten patients among 15 patients the meningeal branches of ICA were dominant feeders. In ten patients out of 15 patients, the embolization from the meningeal branches of ICA was possible. Eight patients out of these ten patients were suffered from high fever and increase of serum level of CRP after the embolization. During the embolization for skull base meningiomas, the existence of collateral pathways between the ICA system and external carotid artery system were identified. The increase of serum levels of CRP might be recognized in the patients that effective embolization were performed.