Posterior semicircular canal dehiscence: a morphologic cause of vertigo similar to superior semicircular canal dehiscence

The aim of this study was to assess imaging findings of posterior semicircular dehiscence on computed tomography and to evaluate incidence of posterior and superior semicircular canal dehiscence in patients presenting with vertigo, sensorineuronal hearing loss or in a control group without symptoms related to the inner ear. Computed tomography was performed in 507 patients presenting either with vertigo (n=128; 23 of these patients suffered also from sensorineuronal hearing loss), other symptoms related to the inner ear, such as hearing loss or tinnitus (n=183) or symptoms unrelated to the labyrinth (n=196). All images were reviewed for presence of dehiscence of the bone, overlying the semicircular canals. Twenty-nine patients had superior semicircular canal dehiscence. Of these patients, 83% presented with vertigo, 10% with hearing loss or tinnitus and the remaining 7% with symptoms unrelated to the inner ear. In 23 patients dehiscence of the posterior semicircular canal was encountered. Of these patients, 86% presented with vertigo, 9% with hearing loss or tinnitus and 5% with symptoms unrelated to the inner ear. Defects of the bony overly are found at the posterior semicircular canal, in addition to the recently introduced superior canal dehiscence syndrome. Significant prevalence of vertigo in these patients suggests that posterior semicircular canal dehiscence can cause vertigo, similar to superior semicircular canal dehiscence. Electronic Publication     

Evaluation of the anterior and posterior ethmoidal canal by computed tomography

AIM: To examine the anatomy, length and angulation of the anterior and posterior ethmoidal canals (AECs and PECs) using computed tomography (CT), and to determine the anatomical landmarks in which the canals are expected to be seen in transverse and coronal planes. MATERIALS AND METHODS: CT images of 150 patients were analysed. One, 2, and 3 mm thick sections were obtained separately in axial and coronal images. The frequency of visualization of the AECs and PECs, and if present, a third canal, was noted. The course and the angulation of the AEC and the PEC in transverse and coronal planes were recorded. On axial sections the distance between the AEC and PEC and the previously defined landmarks were measured. On coronal images, the distances were calculated from the thickness of the cross-section and the number of sections between the various structures. RESULTS: The AEC was identified as a separate canal in 84% of patients, and was embedded in the ethmoid roof in 16%. The PEC was seen as a separate canal in 8% and was present in the ethmoid roof in 92%. On the 1 mm thick coronal and transverse sections, a third canal was identified at the junction of the middle and posterior third of the AEC-PEC distance in both of the images. The average lengths of these canals were 4-12 mm (mean 8.2 mm) for the AEC, and 2-13 mm (mean 7.6 mm) for the PEC. CONCLUSIONS: To avoid the complications that can develop during endoscopic sinus surgery; the course, length and the angulations of the anterior and posterior ethmoidal arteries and their canals can be identified by CT in standard positions if a sufficiently thin section thickness is used. The present study has shown the exact CT localization of the AECs and PECS, which are frequently overlooked when evaluating para-nasal sinuses.     

Nutrient canal of the fibula

Objective. To investigate the radiological features of the nutrient canal in the fibula. Design and patients. One hundred and seventy-nine dried fibulae were studied regarding the type, number, location, and direction of the nutrient canal. They were classified into a usual type (type I: a radiolucent line confined to the cortex) and an atypical type (type II: a radiolucent line extending beyond the cortex). Results. Among the total of 230 nutrient canals seen on radiography, 197 (86%) were type I and 33 (14%) were type II. On CT scans, the ossified rim of the canal extended into the medullary cavity in type II canals. The most common site was the posteromedial aspect in both type I and type II canals. Type II canals were significantly more common in fibulae with two or three nutrient canals. The frequency of the upward direction was more common in type II canals. Conclusion. Nutrient canals with extension of the ossified rim into the medullary canal are the cause of linear lucency that may simulate a fracture. Their features are slightly different from those of usual canals. Received: 13 July 1999 Revision requested: 20 September 1999 Revision received: 13 October 1999 Accepted: 18 October 1999     

Semicircular canal dehiscence: comparison of T2-weighted turbo spin-echo MRI and CT

We assessed the value of MRI for delineation of dehiscence of the superior or posterior semicircular canal, as compared with CT, the current standard study for this entity. We reviewed heavily T2-weighted fast spin-echo images and high-resolution CT of the temporal bones of 185 patients independently semicircular canal dehiscence and its extent. In 30 patients (19 men, 11 women) we identified dehiscence of the bone over the superior and/or posterior semicircular canal on MRI. In 27 of these cases CT also showed circumscribed bone defects. In one patient dehiscence of the superior semicircular canal was initially overlooked on MRI, but seen on CT. MRI imaging thus had a sensitivity of 96% and specificity of 98%. Knowledge of the appearances of this entity on MRI may contribute to early diagnosis in patients with vertigo due to semicircular canal dehiscence.     

Semicircular canal dehiscence: Frequency and distribution on temporal bone CT and its relationship with the clinical outcomes

Purpose

In this study, we aimed to investigate the frequency of SCD and its distribution and relationship with clinical outcomes on thin-section CT of the temporal bone.

Materials and methods

Digital temporal bone CT images of 850 consecutive patients (1700 temporal bone CTs, 5100 SCs) who presented with a range of complaints such as vertigo, deafness, ear pain, fullness, and discharge between January 2008 and December 2011 were re-evaluated. Axial and oblique coronal reconstruction images of the temporal bone were made with a reconstruction thickness of 0.5 mm. Additionally, superior SC was evaluated in two perpendicular planes.

Results

Out of 850 patients, 70 had completely normal temporal bone CT. Ninety-three patients had at least one SCD. In the temporal bone-based evaluation, 119 (26 bilateral, 67 unilateral) of 1700 temporal bones (7%) showed dehiscence. The SC-based evaluation revealed 125 SCD (2.5%) in 5100 SCs. The total number and rates of SCD were as follows: superior 103 (82.4%), posterior 13 (10.4%), and lateral nine (7.2%). Twenty of the 93 patients with SCD (21.5%) revealed no other findings on their temporal bone CTs. We determined a significant correlation between vestibular complaints, conductive hearing loss and SCD but there was no correlation between mixed, sensorineural hearing loss and SCD.

Conclusion

We determined the frequency of SCD in 11% of patients and 7% of temporal bones. With regards to the distribution, the superior SC showed the highest dehiscence rate (82.4%). We found a significant correlation between vestibular symptoms, conductive hearing loss and SCD.     

Endovascular Treatment of the Carotid Stump Syndrome

In patients with an occluded internal carotid artery, the carotid stump syndrome is a potential source of microemboli that pass through the ipsilateral external carotid artery and the ophthalmic artery to the territory of the middle cerebral artery. Thus, the syndrome is associated with carotid territory symptoms although the internal carotid artery is occluded. Surgical exclusion of the internal carotid artery associated with endarterectomy of the external carotid artery has been described as the gold standard of treatment by many authors. This report is the second case, to our knowledge, of endovascular treatment of the carotid stump syndrome with the use of a stent-graft.     

颈动脉间隙神经瘤CT评价

颈动脉间隙神经瘤为颈部软组织常见良性肿瘤。术前未明确颈动脉体瘤者手术大多未能切除，故在术前鉴别颈动脉体瘤与其他神经瘤至关重要。回顾性分析经手术病理证实的颈动脉间隙神经瘤１１例，计颈动脉体瘤、交感神经瘤各４例，迷走神经瘤３例，研究它们各自的ＣＴ征象。     

弯曲根管的根管预备

目的 总结一套利用手用器械对弯曲根管进行根管预备的方法。方法 在逐步后退法基础上，应用抗弯曲法(anti-curvature)进行根管预备。结果 对不同年龄、不同狭窄程度的52例磨牙近中、近中颊侧的弯曲根管的预备，经充填后的X线片观察，均未见根管明显拉直现象。结论 抗弯曲法对磨牙近中、近中颊侧弯曲根管的根管预备效果满意。     

Extracranial Carotid Artery Stenting in Surgically High-Risk Patients Using the Carotid Wallstent Endoprosthesis: Midterm Clinical and Ultrasound Follow-Up Results

The purpose of this study was to evaluate the feasibility, safety and midterm outcome of elective implantation of the Carotid Wallstent® in patients considered to be at high surgical risk. In a prospective study, 54 carotid artery stenoses in 51 patients were stented over a 24-month period. Three patients underwent bilateral carotid artery stenting. Institutional inclusion criteria for invasive treatment of carotid occlusive disease (carotid endarterectomy or carotid artery stenting) are patients presenting with a 70% or more symptomatic stenosis and those with an 80% or more asymptomatic stenosis having a life-expectancy of more than 1 year. All patients treated by carotid artery stenting were considered at high risk for carotid endarterectomy because of a hostile neck (17 patients—31.5%) or because of severe comorbidities (37 patients—68.5%). No cerebral protection device was used. Of the 54 lesions, 33 (61.1%) were symptomatic and 21 (38.8%) were asymptomatic. Follow-up was performed by physical examination and by duplex ultrasonography at 1 month, 6 months, 1 year and 2 years after the procedure. All 54 lesions could be stented successfully without periprocedural stroke. Advert events during follow-up (mean 13.9 ± 5.7 months) were non-stroke-related death in 6 patients (11.1%), minor stroke in 4 stented hemispheres (7.4%), transient ipsilateral facial pain in 1 patient (1.8%), infection of the stented surgical patch in 1 patient (1.8%) and asymptomatic instent restenosis in 4 patients (7.4%). The percutaneous implantation of the Carotid Wallstent®, even without cerebral protection device, appears to be a safe procedure with acceptable clinical and ultrasonographic follow-up results in patients at high surgical risk. But some late adverse events such as ipsilateral recurrence of non-disabling (minor) stroke or instent restenosis still remain real challenging problems.     

Radioanatomy of the singular nerve canal

The singular canal conveys vestibular nerve fibers from the ampulla of the posterior semicircular canal to the posteroinferior border of the internal auditory meatus. Radiographic identification of this anatomic structure helps to distinguish it from a fracture. It is also a landmark in certain surgical procedures. Computed tomography (CT) examinations of deep-frozen temporal bone specimens were compared with subsequently prepared plastic casts of these bones, showing good correlation between the anatomy and the images. The singular canal and its variable anatomy were studied in CT examinations of 107 patients. The singular canal could be identified, in both the axial and in the coronal planes. Its point of entry into the internal auditory meatus varied considerably. offprint requests to: C. Muren     

颈动脉支架成形术治疗颈动脉粥样硬化性狭窄

目的：总结血管内支架治疗颈动脉粥样硬化性狭窄的临床体会，探讨该技术的适应证、并发症防治及初步疗效。材料和方法：55例颈动脉狭窄患者(2000年10月至2001年12月，40例有反复的短暂性脑缺血发作或脑梗死，1例小脑出血，14例无明显症状)在球囊扩张后安装自膨胀血管内支架，其中33例还应用不可脱卸球囊进行支架内再扩张。结果：53例支架定位准确，2例释放支架时支架向近端移位。31例患者狭窄完全消失，20例狭窄程度减少90％以上，4例减少70％，术中1例发生短暂脑缺血性发作，1例发生脑梗死。临床随访1－15个月(平均6．1个月)，仅1例术后2个月发作TIA　1次。颈动脉超声随访42例，DSA随访15例患者颈动脉均无再狭窄发生(6－12月)。结论：血管内支架成形术是治疗颈动脉狭窄的安全而有效方法，长期疗效有待于进一步观察。     

CE-MRA在颈动脉狭窄中诊断价值的研究

目的探讨对比增强磁共振血管造影(CE-MRA)对颈动脉狭窄及狭窄程度的诊断价值。资料与方法对54例有临床缺血症状的患者行CE-MRA检查后1周内行DSA检查,将其颈动脉影像学结果进行比较。结果 CE-MRA对颈动脉狭窄的敏感性、特异性、假阴性、假阳性和诊断符合率分别为94.12%、91.89%、5.88%、8.11%和92.59%;对狭窄程度进行分级后再次进行准确性的比较,发现CE-MRA对颈动脉狭窄的敏感性、特异性、假阴性、假阳性和诊断符合率分别为91.67%、80.95%、8.33%、19.15%和83.33%;将正常血管剔除后进行狭窄程度准确性比较,其诊断符合率为55%。结论 CE-MRA可作为颈动脉狭窄的一种筛查手段,但仍无法准确评价颈动脉狭窄的程度。     

Dual Antiplatelet Regime Versus Acetyl-acetic Acid for Carotid Artery Stenting

Carotid artery stenting has been proposed as an option treatment of carotid artery stenosis. The aim of this single-institution study is to compare the dual-antiplatelet treatment and heparin combined with acetyl-acetic acid, in patients who underwent carotid artery stenting. We compared 2 groups of 50 patents each who underwent carotid artery stenting for primary atherosclerotic disease. Group A received heparin for 24 h combined with 325 mg acetyl-acetic acid and group B received 250 mg ticlopidine twice a day combined with 325 mg acetyl-acetic acid. Outcome measurements included 30-day bleeding and neurological complications and 30-day thrombosis/occlusion rates. The neurological complications were 16% in group A and 2% in group B (p < 0.05). Bleeding complications occurred in 4% in group A and 2% in group B (p > 0.05). The 30-day thrombosis/occlusion rate was 2% in group A and 0% in group B (p > 0.05). Dual antiplatelet treatment is recommended in all patients undergoing carotid artery stenting.     

Transcatheter Closure of a Chronic Iatrogenic Arteriovenous Fistula Between the Carotid Artery and the Brachiocephalic Vein with an Amplatzer Duct Occluder in Combination with a Carotid Stent

We report an original method of transcatheter closure of an arteriovenous fistula using the combination of an Amplatzer PDA occluder and a carotid stent. The fistula was between the left carotid artery and the brachiocephalic vein. The patient had significant left-to-right shunt and was highly symptomatic. Due to the large orifice and pseudoaneurysmatic enlargement of the fistula, we had to use a large Amplatzer PDA occluder and the protruding part of the PDA device disk had to be covered with a carotid stent. The fistula was completely closed. The patient stopped having symptoms and, 2 years after the procedure, the effect persists.     

Carotid artery stenting for stenosis with intraluminal thrombus

Since intraluminal thrombus in the context of carotid artery stenosis is rarely encountered, treatment for this condition remains controversial. The present paper describes six cases of carotid artery stenosis with thrombus and discusses the efficacy and complications of carotid artery stenting (CAS). From April 2002 to May 2004, six patients with carotid artery stenosis and intraluminal thrombus receiving medical therapy underwent CAS at our institution. CAS was performed with distal protection alone (method 1) in three patients, and three other patients underwent CAS with reversed-flow system and distal protection (method 2). Two of six patients experienced worsening neurologic symptoms despite medical therapy. All six patients were successfully treated with CAS and showed satisfactory patency of the artery. Embolic lesions were detected on diffusion-weighted MRI after the procedure in all patients treated with method 1 but not in patients treated with method 2. Complications included stent thrombosis (n=1) and in-stent thrombus (n=1). All six patients achieved a modified Rankin Scale 1 or 2 classification at 30 days after stenting. In conclusion, CAS was feasible for stenosis even with intraluminal thrombus. Use of method 2 for this condition may reduce the incidence of thromboembolic events although our series was small in number.     

DSA对颈动脉体瘤的诊断评价

本文报告经手术证实的9例颈动脉体瘤的动脉DSA表现,对DSA在颈动脉体瘤术前诊断的价值及其优越性进行了评价。指出颈动脉体瘤的血管造影特征为造影早期肿瘤染色,延续至静脉期,在DSA上显示更为典型。DSA不受骨骼干挠比常规血管造影有更高的分辩率,可以发现细小的供血动脉。本组2例显示颈内动脉发出细小分支参于肿瘤血供,过去文献报道较少。     

Carotid angioplasty and stent placement for restenosis after endarterectomy

Introduction Recurrent carotid stenosis following endarterectomy is a common complication, and reoperation may be associated with increased morbidity. The goal of this study was to determine the procedural safety and long-term complication rates of carotid angioplasty and stenting for recurrent stenosis. Methods Of 248 consecutive carotid angioplasty and/or stenting procedures performed at our institution between March 1996 and November 2005, 83 procedures for recurrent stenosis following endarterectomy were performed in 75 patients (mean age 68 years; 43 men, 32 women) without cerebral protection devices. The patients’ medical records were retrospectively reviewed for vascular imaging reports and available clinical follow-up. Procedural and long-term complication rates were calculated. Results Recurrent stenosis was reduced from a mean of 80.6% to no significant stenosis in 82 of 83 procedures. The procedural stroke rate was 3 out of 83 procedures (3.6%). The procedural transient ischemic attack (TIA) rate was 2 out of 83 procedures (2.4%). Mean follow-up was 22.4 months (range 0.1 to 86.7 months) with at least 6 months follow-up for 54 of 83 procedures (65%). There were five TIAs and no strokes on follow-up (new TIAs at 25.5 and 43.4 months; recurrent TIAs at 1, 11.1, and 12 months, all with normal angiograms). The composite 30-day stroke, myocardial infarction, or death rate was 5 of 83 procedures (6.0%). Conclusion In this series, angioplasty and stenting were effective in relieving stenosis secondary to recurrent carotid disease after endarterectomy, and have low rates of ischemic complications.