Three-dimensional vessel wall imaging with 1.5-T MRI to visualize invisible occluded cerebral artery.

BACKGROUND: Endovascular thrombectomy (EVT) is performed for acute ischemic stroke (AIS) caused by large vessel occlusion; therefore, preoperative visualization of the occluded invisible vessel course reduces complications and ensures success. Three-dimensional (3D) proton density-weighted (PDW) vessel wall imaging (VWI) using variable refocusing flip angle pulse-turbo spin-echo sequences (VRFA-TSE) with 3.0-T magnetic resonance imaging (MRI) can provide this information. PURPOSE: To assess the effectiveness of 3D PDW-VWI using 1.5-T MRI without VRFA function. MATERIAL AND METHODS: Five consecutive patients with AIS caused by large vessel occlusion underwent EVT in our institute. VWI with 1.5-T MRI using 3D PDW-fast spin echo (FSE) technique was added to conventional brain imaging. RESULTS: PDW-FSE was successfully performed in all cases. 3D PDW-FSE was useful to visualize both the anterior and posterior circulations by clearly revealing invisible vessels but could not demonstrate the length and size of the clot in all five cases. CONCLUSION: 3D PDW-FSE with 1.5-T MRI without VRFA could clearly depict the course of the invisible occluded artery and might support favorable outcomes after EVT in patients with AIS.

Three-dimensional vessel wall MRI to characterize thrombus prior to endovascular thrombectomy for large vessel occlusion stroke.

BACKGROUND AND PURPOSE: Endovascular thrombectomy (EVT) for acute ischemic stroke (AIS) caused by large vessel occlusion requires rapid and reliable imaging of the vessel course including the clot to reduce complications and ensure success. However, no method to acquire this information has been established. METHODS: Six consecutive patients with AIS caused by large vessel occlusion underwent EVT in our institute. High-resolution vessel wall MRI was performed using three-dimensional (3D) variable refocusing flip angle pulse and turbo spin-echo sequences (VRFA-TSE) with the volume isotropic turbo spin-echo acquisition (VISTA) technique. This study evaluated the effectiveness of 3D proton density-weighted (PDW) VRFA-TSE (called PDW-VISTA) compared with T2-weighted (T2W) VRFA-TSE (called T2W-VISTA) to demonstrate the cerebral vessels including the occluded invisible lesion. RESULTS: PDW-VISTA and T2W-VISTA were successfully performed in all cases. PDW-VISTA was more useful to visualize the anterior circulation than T2W-VISTA by clearly revealing invisible vessels, whereas PDW-VISTA and T2W-VISTA had similar findings in the posterior circulation. The vessel courses shown by 3D PDW-VISTA imaging before treatment and digital subtraction angiography after treatment showed good agreement in all cases. Furthermore, 3D PDW-VISTA imaging demonstrated the length and size of the clot. CONCLUSIONS: PDW-VISTA imaging was found to more clearly depict the cerebral vessels including occluded lesion than T2W-VISTA imaging. Findings of thrombus size and length were important for correctly placing the stent retriever and securing safety during the procedure.

[Usefulness of Bilateral rSO2 Monitoring for Predicting Cerebral Hyperperfusion Syndrome after Carotid Artery Stenting].

OBJECTIVE: Cerebral hyperperfusion syndrome(CHS)and cerebral hyperperfusion phenomenon(CHP)induce intracranial hemorrhage and can become critical complications after carotid artery stenting(CAS). The purpose of the present study was to predict and avoid CHS after CAS using bilateral rSO2 intraoperative monitoring. METHODS: We retrospectively analyzed 100 consecutive patients who underwent CAS between January 2012 and May 2014 in our institution. We performed continuous bilateral rSO2 monitoring from anesthetic induction to the day following CAS. CHS was defined as the deterioration of neurological conditions post-CAS, no ischemic changes on post-CAS head CT or brain MRI, an increase in cerebral blood flow(CBF)and cerebral blood volume(CBV), and shortening of the mean transit time(MTT)or time to peak(TTP)on CT perfusion. To compare the CHS/CHP group and non-CHS/CHP group, we defined four parameters:rSO2 difference(rSO2 at the endpoint of the procedure-baseline rSO2), ΔrSO2 difference(affected side rSO2 difference-unaffected side rSO2 difference), rSO2 ratio(rSO2 at the endpoint of the procedure/baseline rSO2), and ΔrSO2 ratio(affected side rSO2 ratio/unaffected side rSO2 ratio). RESULTS: There were 2 CHS cases(2.2%)and 3 CHP cases(3.3%). In the CHS/CHP group, the ΔrSO2 difference and ΔrSO2 ratio were significantly higher than those in the non-CHS/CHP group(p value<0.05);however, no significant differences were found in the affected side rSO2 difference(p value=0.063)and affected side rSO2 ratio(p value=0.054)between the groups. CONCLUSION: We could promptly detect CHS and CHP in all cases by using continuous bilateral rSO2 monitoring and analysis of the ΔrSO2 difference and ΔrSO2 ratio.

The safety and efficacy of preoperative embolization of meningioma with N-butyl cyanoacrylate.

OBJECTIVE: Preoperative embolization of meningioma is commonly performed; however, there is no consensus on the best embolic material to reduce intraoperative blood loss and surgery time. METHOD: We retrospectively assessed the safety and efficacy of 56 cases of preoperative embolization of the middle meningeal artery with N-butyl cyanoacrylate (NBCA) in 105 cases of surgery for meningioma. We also defined a blood loss to tumor volume ratio to compensate for bias caused by tumor volume, and analyzed limited cases (the embolized group n = 52, the non-embolized group n = 21) of the convexity, the parasagittal region, the falx, and the sphenoidal ridge. RESULT: The blood loss to tumor volume ratio was significantly less in the embolized group (p < 0.007). Preoperative embolization could be useful for cases with the external carotid artery as the dominant feeder vessel (p < 0.02); however, the efficacy decreased for cases with an internal carotid artery feeder. Transient complications occurred in four cases (hemiparesis secondary to edema: two cases; intratumoral bleeding: one case; trigeminal nerve disorder: one case). The cases that showed a postoperative increase in edema or intratumoral bleeding were large tumors with the early filling of veins. For such cases, surgeons should pay close attention to slow injection speed and higher NBCA viscosity, not to cause the occlusion of draining vessels. CONCLUSION: Tumor embolization with NBCA can be safely performed, and the procedure significantly reduces intraoperative blood loss.

Risk factors for coil protrusion into the parent artery and associated thrombo-embolic events following unruptured cerebral aneurysm embolization.

OBJECTIVE: Advances in vascular reconstruction devices and coil technologies have made coil embolization a popular and effective strategy for treatment of relatively wide-neck cerebral aneurysms. However, coil protrusion occurs occasionally, and little is known about the frequency, the risk factors and the risk of thrombo-embolic complications. METHOD: We assessed the frequency and the risk factors for coil protrusion in 330 unruptured aneurysm embolization cases, and examined the occurrence of cerebral infarction by diffusion-weighted magnetic resonance imaging (DW-MRI). RESULT: Forty-four instances of coil protrusion were encountered during coil embolization (13.3% of cases), but incidence was reduced to 33 (10% of cases) by balloon press or insertion of the next coil. Coil protrusion occurred more frequently during the last phase of the procedure, and both a wide neck (large fundus to neck ratio) (OR = 1.84, P = 0.03) and an inadequately stable neck frame (OR = 5.49, P = 0.0007) increased protrusion risk. Coil protrusions did not increase the incidence of high-intensity lesions (infarcts) on DW-MRI (33.3% vs 29% of cases with no coil protrusion). However, longer operation time did increase infarct risk (P = 0.0003). Thus, tail or loop type coil protrusion did not increase the risk of thrombo-embolic complications, if adequate blood flow was maintained. CONCLUSION: Coil protrusion tended to occur more frequently in cases of wide-neck aneurysms with loose neck framing. Moderate and less coil protrusion carries no additional thrombo-embolic risk, if blood flow is maintained, which can be aided by additional post-operative antiplatelet therapy.

Rupture of an aneurysm of the superior cerebellar artery feeding a dural arteriovenous fistula.

We experienced a very rare case of bleeding from an aneurysm of a branch of the superior cerebellar artery, which feeds a dural arteriovenous fistula (DAVF) of the posterior fossa. The aneurysm was not detected on initial angiography and 2 episodes of rebleeding resulted in deterioration of the patient's condition. Although rare, aneurysms of the pial feeding arteries should be considered as a cause of bleeding in cases of DAVF.

Risk factors and prevention of guiding catheter-induced vasospasm in neuroendovascular treatment.

Mechanically-induced vasospasm often occurs during guiding catheter insertion, occasionally preventing catheter advancement to the desired location. Delicate manipulation would be impossible without the proper positioning of guiding catheters, and vasospasm-induced cerebral hypoperfusion may cause thrombotic complications. From June 2012 to December 2013, we prospectively analyzed 150 endovascular treatment cases, excluding acute cases, for the frequency of vasospasm, risk factors, and countermeasures. The associated risk factors such as the Japanese-style State-Trait Anxiety Inventory (STAI) score; anatomy and devices; and the efficacies of warm compresses, intra-arterial lidocaine/nicardipine, and tranquilizers were analyzed. Groups 1, 2, and 3 comprised 50 patients each with controls, tranquilizer administration, and prophylactic warm compresses/intra-arterial drug injection, respectively. Moderate or severe vasospasm was seen in approximately 40% patients in each group; however, severe vasospasm was absent in Group 3. Mild vasospasm-induced cerebral infarction occurred in one patient each in Groups 1 and 2. Vasospasm during diagnostic angiography [odds ratio (OR) = 10.63; P = 0.01], many ≥ 30° vessel curves [OR = 4.21; P = 0.01], and the high STAI score [OR = 1.84; P = 0.01] were risk factors for severe vasospasm. Although the relationship between anxiety and sympathetic tone remained unclear, tranquilizer administration relieved vasospasm. Warm compresses and the intra-arterial drug infusion were also useful for relieving vasospasm. Prophylactic measures such as a tranquilizer and warm compresses are expected to alleviate vasospasm; in addition, countermeasures such as the intra-arterial injection of lidocaine/nicardipine are effective.

Endovascular treatment of ruptured dissecting aneurysms of the posterior inferior cerebellar artery.

BACKGROUND: Dissecting aneurysms of the posterior inferior cerebellar artery (PICA) are rare, with optimal treatment strategies not well established according to the location of the aneurysm on the PICA. We present our single-center experience of endovascular treatment of ruptured dissecting aneurysms of the PICA. METHODS: Nine patients with ruptured dissecting aneurysms of the PICA were treated with endovascular embolization at our facility from August 1997 to December 2011. A retrospective chart review study was conducted to examine the efficacy of endovascular treatment and clinical outcome. RESULTS: The shape of the aneurysms was saccular in five cases, fusiform in three cases and an abrupt cut-off of the PICA in one case. Aneurysmal sac embolization was feasible in five cases and parent artery (PICA) occlusion was performed in four cases. Eight cases (89%) achieved good recovery (modified Rankin Score ≤ 2). There were no clinical/technical complications in this small series. CONCLUSIONS: Endovascular treatment of ruptured dissecting aneurysms of the PICA is safe and efficient.

Local thrombus formation at the coil-parent artery interface during endovascular coil embolization of cerebral aneurysms.

BACKGROUND AND PURPOSE: Fresh thrombus formation at the coil-parent artery interface around the neck of aneurysms is sometimes observed during coil embolization of cerebral aneurysms. We retrospectively analyzed the factors associated with local acute thrombus formation from the data of patients treated over a period of 5 years at our institute. METHODS: Between November 2004 and March 2009, 242 patients harboring 250 aneurysms were treated with endovascular coil embolization at our institute. The patients were divided into two groups: Group A included 107 patients who were treated and followed up during the initial 29 months of the study, and group B included 135 patients who were treated and followed up during the later 24 months of the study. Clinical and angiographic variables of the procedures were statistically tested for correlation with thrombus formation in the parent arteries. RESULTS: Fresh thrombus formation occurred in six patients with unruptured aneurysms (15%) and 11 patients with ruptured aneurysms (14%) in group A. Among the patients with unruptured aneurysms, the dome-to-neck ratio and location of the aneurysms were independently associated with the risk of thrombus formation, whereas among patients with ruptured aneurysms, a higher World Federation of Neurological Surgeons (WFNS) grade and longer interventional duration were significantly associated with thrombus formation. However, fresh thrombus formation occurred in only two patients with unruptured aneurysms (2.9%) and three patients with ruptured aneurysms (4.4%) in group B. There were no factors that were significantly associated with thrombus formation in all Group B patients. CONCLUSIONS: With regard to coil embolization treatment, anatomical and morphological factors seem to be related to intraprocedural thrombus formation in patients with unruptured aneurysms, whereas duration of the intervention and preoperative status are associated factors in patients with ruptured aneurysms. Careful comparison of the thrombus with control angiograms is important to prevent thrombembolic complications. Moreover, the rate of fresh thrombus formation during coil embolization has decreased over the past 5 years at our institute, suggesting the possibility of lowering the incidence of these complications by early detection and treatment.

Embolization using endovascular technique in acute and chronic stages of traumatic ophthalmic artery aneurysm - case report - .

A 44-year-old man presented with traumatic aneurysm of the left ophthalmic artery. The first coil embolization intervention achieved relatively tight packing of the aneurysm and the parent artery. After 5 months, a second embolization procedure was required because of recurrence of the aneurysm with transition of the intraaneurysmal coil formation. No recurrence occurred after the second embolization. We thought that the first embolization might have prevented catastrophic rupture, whereas the second embolization resulted in complete obliteration of the aneurysm. No entity of the aneurysmal wall formation of the current traumatic aneurysm in the acute stage may have resulted in the recanalization of the aneurysm followed by the second intervention. The stability of the wall in the chronic stage may correlate with the complete obliteration.

Dural arteriovenous fistula of the anterior cranial fossa with carotid artery stenosis treated by simultaneous transarterial embolization and carotid artery stenting.

A 71-year-old male presented with a rare case of dural arteriovenous fistula (AVF) of the anterior cranial fossa associated with carotid artery stenosis manifesting as a transient visual disorder. The therapeutic strategy was complicated because the collateral network to the ischemic brain from the external carotid artery was associated with the dural AVF. Transarterial embolization of the shunt was performed simultaneously with carotid artery stent placement. The patient showed good recovery despite a tiny skin ulcer around his nose.

Three-dimensional digital subtraction angiography for endovascular treatment of direct carotid-cavernous fistula -case report-.

A 63-year-old woman with a direct carotid-cavernous fistula (CCF), manifesting as sudden onset of severe headache and pulsatile tinnitus suffered during coronary angiography, was successfully treated with transarterial embolization based on the anatomical information obtained from volume-rendered three-dimensional digital subtraction angiography (3D DSA) images. 3D DSA is useful for understanding the configuration of such fistulas accurately and devising a therapeutic strategy for the endovascular treatment of direct CCFs.

[Percutaneous transluminal angioplasty for memory disturbance caused by stenosis of the innominate artery].

It is well known that significant narrowing of the subclavian or innominate artery may cause cerebrovascular ischemic symptoms. We report a case of a 62-year-old man who was suffering from progressive cognitive impairment and was treated by perctaneous transluminal angioplasty (PTA). The patient had undergone aorto-bifemoral bypass, left femoropopliteal bypass, and right femoral artery endoarterectomy. On admission, he was alert, but had memory impairment, especially delayed recall. He complained of dizziness and dysesthesia on his right upper extremity which got worse on exertion. The right radial pulse was diminished and the right brachial blood pressure was lower about 40 mmHg than the left. Angiography demonstrated severe stenosis of the innominate artery near its origin, hypoplasty of the left horizontal anterior cerebral artery segment (Al), and dilation of the left external carotid artery. Left vertebral arteriography revealed retrograde flow of the right vertebral artery in the late arterial phase. Single photon emission computed tomography (SPECT) revealed marked reduction in cerebral blood flow to the left frontal lobe. The patient underwent PTA of the innominate artery with satisfactory results. Cognitive impairment improved remarkably after the angioplasty. The right radial pulse was quite palpable, and the bilateral brachial blood pressures were the same. The cerebral blood flow was increased in SPECT. Memory disturbance can be generated by stenosis of the innominate artery. PTA is one of the effective methods to reverse such cognitive impairment.

[Embolic complications by ink clots removed from syringes during cerebral angiography].

UNLABELLED: We noted, during cerebral angiography, that the contrast medium was contaminated with numerous small black ink clots from gradation marks on syringes. In this report, we show that ink can be removed from syringes in solid form, and that they may result in embolic complications during cerebral angiography. MATERIALS AND METHODS: To demonstrate that the ink from gradation marks on syringes can come off in a solid form and attach itself to the gloves during cerebral angiography, syringes were gripped many times (just as in an angiographic procedure) after immersion in contrast medium or 0.9% saline for 10 minutes. To see if difference of contrast medium and syringes could affect the removing of ink, five types of nonangiographic syringes and one type of angiographic syringe were rubbed with gauze after certain time periods after immersing them in four kinds of contrast medium or 0.9% saline. RESULTS: Ink attached itself to the gloves in a solid form by repeated gripping due to adherence of contrast medium. Ink was removed from all nonangiographic syringes by rubbing after immersion in any type of contrast medium for two hours. Gradation marks on angiographic syringes were stable with all types of contrast medium. CONCLUSIONS: Thus, ink for gradation marks on nonangiographic syringes, which is easily removed in a solid form due to contrast medium, can be the source of embolic complication during cerebral angiography.

[A study of intraarterial pressure changing during cerebral angiography].

BACKGROUND: Elevation of cerebral blood pressure induced by injection of contrast medium has been postulated as a major cause of rerupture of cerebral aneurysms during angiography. The current study was performed to clarify whether intra-arterial pressure elevation occurs during contrast injection. MATERIALS AND METHODS: The study included six patients. To confirm the accuracy of pressure measurement, a pressure wire (SmartWire) was used. The changes in intravascular pressure were measured by the pressure wire and through a microcatheter and a guiding catheter The data from these modalities were then compared. The contrast injection flow rate was 4 ml/s in ICAG (internal carotid angiography), 3 ml/s in VAG (vertebral angiography) and 5 ml/s in CAG (carotid angiography), and all injections were administered without contrast wedging, regurgitation or mechanical spasm in adjacent arteries. RESULTS: The pressure measured through the guiding catheter was the same as that measured with the pressure wire, but the data obtained through the microcatheter was not more than reference data. The changes in pressure were not evident in the distal end of the catheter tip. CONCLUSION: Intra-arterial pressure elevation probably doesn't occur under appropriate injection, resulting in safer cerebral angiography. However, in case a high contrast injection flow rate is required to produce a better image, surgeons should also be aware of the possibility of pressure elevation.

[Transarterial NBCA embolization with transvenous partial outflow obstruction for superior petrosal sinus dural arteriovenous fistula: a case report].

We encountered a case of superior petrosal sinus dural arteriovenous fistula (SPS DAVF) which was treated by a combination of a transvenous and a transarterial approach after the failure of the transvenous approach alone. A 69-year-old man presented with a complaint of progressive left bulbar conjunctival conjestion, exophthalmos, and impaired vision. Cerebral angiography revealed a left SPS DAVF fed by the left middle meningeal artery, the meningeal branches of the left internal carotid artery and the left posterior meningeal artery. Venous drainage proceeded through the cavernous sinus (CS) toward the left superior ophthalmic vein (SOV). Transvenous embolization via the SOV was indicated because the left ipsilateral inferior petrosal sinus contributed to the normal venous return. However the microcatheter to the CS couldn't go through the tortuous SOV. Next a transarterial NBCA (n-butyl-cyanoacrylate) embolization of the affected sinuses was performed under arterial flow control with balloons and the partial coil embolization of the origin of the SOV. The coils in the SOV trapped NBCA and the sinuses were filled slowly with NBCA. The postoperative angiogram confirmed complete obliteration of the DAVF and the patient's ocular symptoms disappeared. DAVF is usually difficult to treat by transarterial embolization with NBCA because of its multiple feeders and high flow drainage. We should therefore carefully observe its structure and the blood flow change with 3D-DSA and the selective angiography while embolizing the DAVE.

[Bilateral ptosis and upper gaze palsy with pupil sparing caused by midbrain hemorrhage].

The arrangement within the midbrain oculomotor nerve complex and crossed innervation of the superior rectus muscle are not elucidated in humans. A 65-year-old woman visited our hospital complaining of difficulty opening her eyes. Neurological examination revealed bilateral ptosis and impaired supraduction. The pupils prompty constricted to light. Results of CT and MRI demonstrated that there was a hematoma located in the dorsal midbrain tegmentum that spared the rostral mid-brain. It was presumed that the nerves of the superior rectus and levator palpebrae lie in the midbrain tegmentum more dorsally and medially than the others. Furthermore, crossed innervation of the superior rectus muscle can explain that lesions located in the dorsal midbrain tegmentum cause more often impaired supraduction.