¹²³I-iomazenil single-photon emission computed tomography (SPECT) was developed to detect epileptic foci in patients who need surgical focus resection. ¹²³I-iomazenil binds to central benzodiazepine receptors that are abundant in the cerebral cortex. Based on this binding mechanism, we tested the clinical application of ¹²³I-iomazenil SPECT in cerebrovascular diseases. Early and late images after tracer administration show cerebral blood flow and cerebral oxygen metabolism distribution, respectively. The late image/early image on ¹²³I-iomazenil SPECT correlated with the oxygen extraction fraction image on positron emission tomography. This image also predicts the development of cerebral hyperperfusion following carotid endaretectomy. Late images on ¹²³I-iomazenil SPECT show irreversible cognitive decline or neurological deficits. In contrast, tracer uptake in late images on ¹²³I-iomazenil SPECT is sometimes reversibly reduced, and recovery after arterial reconstruction surgery, such as carotid endarterectomy or bypass surgery, correlates with postoperative cognitive or neurological improvement.

We reviewed reports of postoperative visual loss (POVL) with an unexplained cause, following neurosurgery, and the possible involvement of orbital compartment syndrome (OCS) as the etiology. OCS is an ophthalmic emergency characterized by an acute increase in orbital pressure. It is likely to be the cause of orbital symptoms, such as eye pain, ophthalmoplegia, eyelid and conjunctival edema, in addition to visual loss, in patients. Of 69 reported cases of POVL, 47 (68.1 %) were considered OCS, including 39 that were reported under other diagnoses. The possibility of mild OCS could not be ruled out in the remaining 22 patients. OCS is clinically diagnosed, and emergent orbital decompression (even prior to imaging) is essential to prevent permanent visual loss. Although good recovery of visual acuity is unlikely if orbital decompression is performed more than 2 hours after onset, there are reports on effectiveness of this treatment after the 2 hours' time window. The early recognition and diagnosis of this condition are extremely important.

Several recent reports have suggested indirect orbital compression and orbital venous perfusion disorder, caused by scalp flap traction, as a mechanism of OCS after craniotomy.

Ruptured blood blister-like aneurysm (BBA) of the internal carotid artery is a serious condition. Surgical intervention consisting of high-flow bypass and carotid artery occlusion is invasive and carries high risk. Six cases of ruptured BBA were treated with acute-phase endovascular intervention. The intervention was performed under general anesthesia within 72 hours after onset. After deployment of the endovascular stent across the aneurysm neck, platinum coils were placed in the aneurysm sac via a jailed micro-catheter. Another stent was deployed inside the first stent. Follow-up angiography was frequently performed, and additional coil placement was performed in cases of aneurysm regrowth. Three patients experienced no recurrence after the first treatment with two stents and a few coils. All achieved favorable outcomes. Three patients required additional intervention for recurrence and two suffered poor outcomes due to intra-cerebral hematoma and infarction. The other patient died of aneurysm re-bleeding. In conclusion, acute-stage stent-assisted coil embolization effectively prevented re-bleeding of the ruptured BBA. The prognosis depended on hemorrhage severity and aneurysm regrowth.

Objective: Vertebral artery dissection (VAD) accompanied only by pain has a favorable prognosis. However, treatment intervention is required if it exacerbates with varicose deformity because subarachnoid hemorrhage (SAH) is more likely to occur. Herein, the clinical features of VAD accompanied only by pain were investigated.

Methods: The subjects were 112 patients (74 men and 38 women) who developed a VAD accompanied only by pain. Their ages ranged from 18 to 77 years (mean, 49 years). The observation period ranged from 77 days to 115 months (mean, 38 months). The subjects were divided into three groups based on the initial radiographic findings: fusiform dilatation (FD), narrowing or occlusion (N/O), and pearl and string sign (PSS). The clinical course, time course of the imaging findings, surgical treatments, and outcomes were examined.

Results: During the clinical course, SAH (2 cases), ischemia (2 cases), and contralateral dissection (4 cases) were observed. The 112 patients were classified as FD (35 cases), N/O (31 cases), and PSS (46 cases). During the clinical course, the imaging findings improved in 69 cases, remained the same in 2 cases, and became exacerbated in 41 cases. Of these 41 patients, 17 showed varicose deformity and 1 received treatment intervention. The remaining 16 patients subsequently showed improvement/no change on imaging (13 cases), occlusion (1 case), and further enlargement of the varicose deformity (2 cases). Of the two subjects with enlarged varicose deformities, one received treatment intervention and the other showed occlusion on imaging. Six patients received treatment interventions: SAH (2 cases), progression of dissection (1 case), exacerbation of imaging findings (2 cases), and enlargement of varicose deformity (1 case). All these patients had a good prognosis.

Conclusion: Even in exacerbated cases, varicose deformities showed a low rate of rupture at 2 weeks and predominantly showed improvement on imaging. Therefore, treatment interventions should be carefully considered.

Large cerebral aneurysms of the posterior cranial fossa generally have a poor natural history and poor treatment outcomes. Here we investigated the outcomes of the endovascular treatment of large cerebral aneurysms (＞10 mm) of the posterior fossa from April 2010 to October 2018 in 14 lesions (mean age, 56.5 years; 9 men) of non-ruptured vertebral aneurysms and basilar artery trunk aneurysms treated at our hospital. Aneurysm size was 10-15 mm in eight cases and 15 mm or larger in six cases. Two aneurysms were located on the basilar arteries and 12 were located on the vertebral arteries. Treatment was based on aneurysm morphology and development degree of the contralateral vertebral artery, with nine cases of aneurysm embolization and five cases of parent artery occlusion. Post-treatment aneurysm size change was reduced in one case, unchanged in nine cases, and increased in four cases. Of the six patients with aneurysms greater than 15 mm, three increased after treatment; of the eight patients with aneurysms greater than 10 mm but less than 15 mm, only one increased after treatment (p=0.24). There were no significant differences in the presence or absence of aneurysm thrombosis. In the endovascular treatment of large posterior fossa aneurysms, the outcome of aneurysms ＞ 15 mm, with or without thrombosis, is poor, ; thus, it is desirable to elucidate the pathogenesis of aneurysm enlargement and hemorrhage and establish an appropriate course of treatment.

Objective: Stent-assisted coiling is now commonly used to treat wide-necked cerebral aneurysms. However, it remains unclear how stent type affects the safety and efficacy of the coiling procedure. This retrospective study aimed to compare the clinical and angiographic outcomes of braided (LVIS) and laser-cut (Enterprise/Neuroform) stents.

Methods: From September 2010 to March 2019, 61 aneurysms were treated with stent-assisted coiling: 15 with the LVIS stent and 46 with the Enterprise/Neuroform stent. We retrospectively analyzed the clinical outcomes and angiographic Raymond-Roy Occlusion Classification (RROC) results.

Results: Our patients included 8 (13.1%) men and 53 (86.9%) women with a mean age of 60.3 ± 11.7 years. The complete occlusion rate, defined as RROC Class I, on baseline imaging did not differ between groups (braided stent, 5/15 [33.3%]; laser-cut stent, 21/46 [45.6%]). At a mean 11.8 (range, 7.4-13.2) months since embolization, angiography showed that RROC Class I was significantly more frequent with the braided stent (14/15 [93.3%]) versus the laser-cut stent (23/46 [50.0%]) (p ＜ 0.05). There were no significant intergroup differences in procedure-related complications.

Conclusion: Stent type was associated with long-term angiographic outcomes. The braided stent may achieve a higher complete occlusion rate than the laser-cut stent.

The surgical treatment of radiation-induced carotid stenosis is controversial. Here we report a case of carotid endarterectomy (CEA). A 70-year old man with a history of radiotherapy for pharyngeal cancer 20 years prior was admitted with sporadic infarctions in the right cerebral hemisphere. Magnetic resonance angiography (MRA) and subsequent angiography demonstrated 75% stenosis of the right common carotid artery (CCA). Plaque images showed vulnerable plaques extending from the proximal CCA to the carotid bifurcation. The plaque was diagnosed as a radiation-induced lesion; however, its volume was too large for carotid artery stenting. The patient underwent CEA under intraoperative ultrasonography guidance to ensure a site of carotid clamping with less plaque content. The carotid arteries were dissected as usual. The plaque was muddy and protruded upon the carotid incision, but dissection from the media was also as usual. The patient’s postoperative course was uneventful with no neurological deficits and resolution of the right carotid stenosis; however, he died of multiple organ failure 3 months later. The authors concluded that radiation-induced carotid stenosis may be treated with CEA when a plaque is large and vulnerable.

We report a case of ruptured flow-related aneurysm that appeared on the collateral channel between the proximal portion of the occluded vertebral artery (VA) due to dissection and the posterior inferior cerebellar artery (PICA).

A 51-year-old man was admitted to our hospital with complaints of sudden left neck pain and vertigo at X years. On admission, anterior inferior cerebellar artery (AICA) syndrome was observed, and imaging scans demonstrated a left cerebellar hemispheric infarction related to left VA occlusion due to VA dissection. The patient was treated with antiplatelet drugs and discharged with left hearing loss. Periodic outpatient magnetic resonance imaging (MRI) scans were performed, and the MRI findings demonstrated a left VA occlusion that persisted for 3 years.

At X+3 years, the patient suddenly presented with nausea, vomiting, dizziness, and neck pain, followed by loss of consciousness. On admission, subarachnoid hemorrhage (SAH) was observed on head computed tomography (CT). Cerebral angiography demonstrated a left VA occlusion at the proximal portion of the PICA and a flow-related aneurysm that formed on the collateral artery between the V3 portion and the PICA. Emergency aneurysmal trapping was performed without any new neurological deficits. He recovered to a Modified Rankin Scale (mRS) of 2 and was discharged on the 66^th day after admission.

Flow-related aneurysm formation on the collateral channel after VA occlusion due to dissection is a rare complication; however, it should be noted during follow-up.

Here we report a case of bilateral cerebellar infarction treated with suboccipital decompressive craniectomy after thrombectomy for an acute basilar artery occlusion. An 83-year-old woman presented with a sudden consciousness disorder. She had a National Institutes of Health Stroke Scale (NIHSS) score of 17 points on admission. Diffusion-weighted imaging (DWI) and computed tomography (CT) angiography revealed acute ischemic bilateral cerebellar stroke due to basilar artery occlusion. Aspiration catheter thrombectomy was immediately performed and modified Thrombolysis in Cerebral Infarction (mTICI) 3 recanalization was achieved. The next morning, CT and DWI revealed bilateral cerebellar swelling with no ischemic lesions at the brain stem. Subsequently, bilateral large suboccipital decompressive craniectomy with duroplasty was performed via an inverted U-shaped skin incision to sufficiently decompress the posterior fossa. After rehabilitation, her clinical course was relatively favorable. She was discharged at 8 months after onset. Her modified Rankin scale score was 4 points at discharge and she was able to walk with assistance. This case demonstrated that an inverted U-shaped skin incision effectively enables sufficient decompression of the posterior fossa for bilateral cerebellar infarction after thrombectomy.

We describe a case of middle cerebral artery dissection after a mild blunt head trauma. A 63-year-old woman suddenly had right hemiparesis and dysarthria three hours after a blunt head trauma due to a traffic accident. Magnetic resonance (MR) imaging and MR angiography revealed acute infarction in left middle cerebral artery (MCA) region and left MCA occlusion was suspected. Digital subtraction angiography revealed severe stenosis and the presence of intimal flap on the M1 portion of left MCA. We diagnosed dissection of the MCA, and performed endovascular revascularization including stent placement. Eight months later, there was no restenosis and the patient recovered to modified Rankin Scale 2. It should be assumed that MCA dissection occurs several hours after a mild blunt head trauma.

Intracranial pial arteriovenous fistula (pAVF) is uncommon, accounting for approximately 1.6% of all intracranial vascular malformations. High flow pressure renders varices and AVF highly susceptible to rupture and life-threatening hemorrhage.

A 15-year-old girl who presented with headache and visual disturbance was diagnosed with an intracranial pAVF associated with a giant varix in the right occipital lobe. Imaging studies showed anomalous dilatation of the right posterior cerebral artery, a 53 mm thrombosed and calcified varix in the right occipital lobe, and drainage into the transverse sinus. We planned a combined surgery with the goal of reducing the mass and curing the pAVF. The patient underwent coil embolization for the obliteration of an angiographic shunt point; however, shunt flow appeared from the new feeders. We resected the giant varix with an angiographic shunt point completely and safely, with embolization the following day. The patient was discharged without any postoperative intracranial complications. The pathological shunt point was confirmed.

Recently, reports on endovascular surgery for pAVF have increased. Combined surgery that includes safe excision, particularly in cases with mass effects, is required.

A cavernous malformation is known to be accompanied by developmental venous anomalies; however, a concomitant arteriovenous malformation (AVM) is rare. We report a case of a cavernous malformation and AVM. A 14-year-old male adolescent, with a family history of cavernous malformation and concomitant AVM underwent surgical resection of the symptomatic left frontal lobe AVM. Intraoperatively, we detected a concomitant cavernous malformation. Cavernous malformations concomitant with AVMs are rare. The anomaly in our patient may be attributable to venous hypertension secondary to a juvenile AVM or a genetic association, based on the patient's family history.

Here we investigated the usability and advantages of a “flat tip” bayonet-type microforceps (FTM) created by processing the tip of Yasargil bayonet microforceps to a thin and flat shape in blunt dissection (BD) during cerebral aneurysm surgery. The ability of the FTM to apply flat pressure in opposite directions to open a narrow gap and scrape it bilaterally using the edge of the tip was a useful feature during BD near the neck of the aneurysm and for detaching blood vessels that had adhered to the aneurysm wall. Its flat tip enables insertion into a restricted space, and the degree of deformation of the aneurysm or vessel wall required to obtain the same separation space is less than that of the standard bipolar forceps. When BD was performed using FTM to form a space posterior to the aneurysm neck, it was not necessary to apply counter pressure with a suction tube to expand the surgical field. We were able to utilize the original function of the suction tube, such as aspiration of the hematoma and cerebrospinal fluid, with a relatively high degree of freedom within the gap created by the FTM. Because the thin, flat structure of the FTM tip allows tissue contact with a smooth surface, it can gently hold delicate and fragile tissues, such as veins or perforating arteries, with minimal trauma. However, the thinner tip of the FTM decreased its grip strength.

Various surgical instruments for BD are selected according to the intraoperative environment. With an increased understanding of the characteristics and weaknesses of FTM, its use may be appropriate in certain situations.