Agenesis of the internal carotid artery and cavernous sinus hypoplasia with contralateral cavernous sinus meningioma

We report a cavernous sinus meningioma encasing the cavernous internal carotid artery in a patient with congenital agenesis of the contralateral internal carotid artery and cavernous sinus hypoplasia.     

Follow-up MRI in dural arteriovenous malformations involving the cavernous sinus: emphasis on detection of venous thrombosis

Summary Six patients with a dural arteriovenous malformation (dural AVM) involving the cavernous sinus were followed up with magnetic resonance imaging in order to assess change in the lesions. Spin-echo (SE) imaging of three patients in whom the AVM appeared to have closed at least 1 month earlier (two of them spontaneously, and one after external carotid artery embolization) showed neither apparent flow void in the involved cavernous sinus nor evidence of venous thrombosis. SE images of the other three patients who had not been cured by external carotid artery embolization (two of whom were examined within a week of treatment), detected persisting arteriovenous shunts, including high-flow cortical venous drainage, seen as flow void. Two-dimensional time-of-flight MR angiography (2D TOF MRA) was performed simultaneously in three patients. Whereas shunting blood and the normal cavernous sinus were of high intensity, presumed thrombosed cavernous sinuses were isointense with stationary brain tissue. SE imaging can confirm the resolution of arteriovenous shunts, but poorly delineates ver acute and chronic thrombosis of the draining veins. In contrast, 2D TOF MRA directly demonstrates flowing blood, permitting the diagnosis of venous thrombosis; it should be included in follow-up of a dural AVM involving the cavernous sinus when venous thrombosis is suspected.     

Asymmetry of intracranial internal carotid artery on 3D TOF MR angiography: a sign of unilateral extracranial stenosis

The purpose of this case-control study was to determine whether an asymmetry of size of the intracranial internal carotid artery (ICA) on 3D time-of-flight MR angiography (MRA) is predictive of a high-grade cervical ICA stenosis. Ninety-six stroke/TIA consecutive patients were recruited for the study, of whom 32 had unilateral high-grade ICA stenosis (≥70% NASCET) and were included into the case group, and the remaining 64 did not have such high-grade stenosis and were included in the control group. On intracranial MRA, two observers, blinded to the characteristics of cervical ICA stenosis, independently searched for qualitative size asymmetry between ICAs and measured the cross-sectional surface of the intracranial ICAs. An intracranial size asymmetry was seen in 28 of the 32 high-grade stenoses by both readers, and in 10 (reader₁) and 8 (reader₂) of the 64 controls (sensitivity = 88%, specificity = 84–88%). In patients without agenesia of the A1 segment of the circle of Willis (n = 70), sensitivity was ≥90% and specificity = 96%. Surfaces ratios were significantly different (p < 0.001) between cases and controls. However, using ROC curves analysis, the quantitative processing did not improve the detection when compared with the qualitative assessment of intracranial ICA asymmetry. A size asymmetry of the intracranial ICAs reveals the presence of an underlying high-grade cervical stenosis, with a high degree of confidence, especially in patients without anatomical variant of the anterior part of the circle of Willis. This sign may allow an early detection of high-grade cervical carotid stenosis in stroke patients before dedicated neck imaging is performed.     

CT and high-field MRI in septic thrombosis of the cavernous sinuses

Summary In a patient with septic thrombosis of the cavernous sinuses CT demonstrated multiple filling defects due to clot formation, but 1.5 T MRI showed an atypical appearance of the thrombus, possibly because of the sepsis.     

颈内动脉海绵窦段创伤性假性动脉瘤破入蝶窦的CT和MRI诊断

目的评价CT和MRI对颈内动脉海绵窦段创伤性假性动脉瘤（TPA）破入蝶窦的诊断价值.方法对经DSA证实的6例海绵窦段TPA破入蝶窦的CT和MRI资料进行回顾性分析.全部患者均行CT检查,5例行MR检查.结果6例颈内动脉海绵窦段TPA中,CT平扫均显示蝶窦侧壁骨折及其密度增高,2例CT增强扫描均可见蝶窦呈明显均匀强化,强化程度与正常血管一致,海绵窦扩大,1例CT血管成像（CTA）明确显示动脉瘤体与瘤颈.5例行MR SE序列平扫,患者均表现为分层状混杂长T1、混杂长T2信号的血栓,4例尚可见瘤腔内的流空现象;3例增强扫描示蝶窦呈明显均匀强化,强化程度与正常血管一致,其中1例在相位编码方向上流动伪影明显;2例MR血管成像均明确显示瘤体与瘤颈.结论CT和MRI是诊断颈内动脉海绵窦段TPA破入蝶窦的有效非创伤性检查,并可作为手术前后长期随访的良好检查方法.     

Bilateral hypoplasia of the internal carotid arteries with basilar aneurysm

We report a rare case of bilateral hypoplasia of the internal carotid arteries with an associated aneurysm of the basilar tip, studied by CT angiography, MR angiography and digital angiography. The patient became symptomatic with an episode of loss of consciousness, likely due to reduced blood perfusion. The other 20 reported cases of bilateral carotid hypoplasia (only four of which with an associated aneurysm) are reviewed. The findings of noninvasive procedures (including narrowing of the carotid canals on CT) may lead to a correct diagnosis before angiography is performed; they may also help to differentiate angiographic narrowing of the hypoplastic internal carotids from the string sign often observed in some acquired conditions.     

Cavernous haemangioma in the cavernous sinus: case report and review of the literature

We report a cavernous haemangioma in the left cavernous sinus. This lesions very rarely occurs in this site and is difficult to diagnose correctly preoperatively. CT, angiography and MRI permit differentiation of the cavernous haemangioma from other tumours in this region and thereby contribute to a better surgical approach. The radiological features of cavernous haemangioma reported in the literature are summarised. Received: 24 February 1999 Accepted: 1 September 2000     

Topographic anatomy of paraclinoid carotid artery aneurysms: usefulness of MR angiographic source images

We evaluated the usefulness of magnetic resonance angiography (MRA) for showing the topography of paraclinoid carotid artery aneurysms in 27 patients with 30 paraclinoid aneurysms undergoing conventional angiography, three-dimensional time-of-flight MRA and surgery. The anatomy shown on the axial MRA source images was consistent with that found at surgery. The neck of the aneurysm could always be identified on the source images, while it could not be analysed exactly on conventional angiography in 3 cases (10 %). The optic nerves, including those displaced by the aneurysm, were recognised in all patients. The anterior clinoid process was shown as a low-intensity rim or area contiguous with the cortical bone. The source images were of great value in understanding the topography of paraclinoid carotid artery aneurysms. Received: 11 April 1996 Accepted: 12 August 1996     

Assessment of cerebral haemodynamics and vascular reserve in patients with symptomatic carotid artery occlusion: an integrated MR method

We describe an MR-based methodology designed to study cerebral haemodynamic compromise in patients with symptomatic carotid occlusions. We present the results of eight patients who underwent MR angiography of the cervical carotids and circle of Willis, MR imaging of the brain and dynamic gadolinium MR perfusion studies before and after the injection of the carbonic anhydrase inhibitor acetazolamide. All patients showed increased transit times in the symptomatic hemisphere at rest indicating reduced flow. The transit time asymmetries became more pronounced after acetazolamide in all patients because of failed vasodilatation on the affected side. There was an inverse correlation between the degree of increased transit time and the degree of collateralisation around the circle of Willis. We believe that demonstration of both macroscopic vascular anatomy and microvascular reserve is important when assessing patients with possible low-flow states and the described method is a robust means of obtaining that data.     

Atherosclerosis of the carotid artery: Evaluation by magnetic resonance angiography

Carotid artery atherosclerotic plaques (APs) can lead to brain ischemia, an event shown to correlate with both the degree of stenosis and the composition of the AP. Currently, accurate estimates of stenosis can be obtained by either x-ray angiography or three-dimensional time of-flight (TOF) magnetic resonance angiography (MRA). Our purpose was to determine whether three-dimensional TOF MRA images could also provide information on plaque location, morphology, and composition. Seven pre-endarterectomy patients underwent three-dimensional TOF MRA. After endarterectomy, plaque histology was evaluated. Three-dimensional TOF MRA images contained sufficient soft tissue contrast to differentiate the plaques from the surrounding tissues in all cases. Estimation of plaque morphology had 80% correlation with histology. Finally, intraplaque hemorrhage and calcification were depicted as regions of moderately high and very low intensity, respectively. These preliminary results suggest that three-dimensional TOF MRA may be useful in studying the development and progression of carotid atherosclerosis.     

脑静脉窦血栓形成的MRI诊断

目的 :探讨MRI和MR血管成像 (MRA ,MRV)对脑静脉窦血栓形成 (CVST)的诊断价值。方法 :回顾性分析 10例CVST患者的临床和影像资料。全部病例行常规MRI和MRA( 3DTOF)、MRV( 2DTOF)检查 ,其中 9例行增强扫描。结果 :MR常规扫描示脑实质内均出现异常信号 ,仅 1例T2 WI未见异常信号 ,增强扫描 9例全部出现静脉异常强化。有 5例MRA除可见动脉正常显影外 ,还可见受累的静脉和静脉窦显影。MRV示栓塞的静脉窦不显影或显影欠佳。结论 :常规MRI结合MRA、MRV是诊断CVST的无创和有效手段     

Stenotic kinking of the cavernous internal carotid artery with a giant intra-cavernous aneurysm: case report

We report a giant aneurysm of the cavernous internal carotid artery with proximal internal carotid stenosis. The stenosis showed two typical features: a kink at the stenosis and location at the exit from the carotid canal. We believe that the cavernous portion of the internal carotid artery is compressed medially by the giant aneurysm and a kink occurs at the point where the artery leaves the bony carotid canal.     

MR imaging of intracranial vertebral artery occlusion

Summary Magnetic resonance (MR) images of nine patients with intracranial vertebral artery occlusion (five proved, four presumed) have been reviewed. In two of nine, both vertebral arteries were occluded and in five of the nine, the basilar artery was also blocked. All occluded arteries showed absence of flow void and were clearly demonstrated as mildly hypo-mildly hyperintense structures to brainstem parenchyma on the T1-weighted images. In two of five patients with basilar artery occlusion, retrograde filling of the distal basilar artery was detected. Thus, MR imaging, in particular the T1-weighted image, is a pertinent diagnostic modality for evaluating intracranial vertebral artery occlusion. Angiography does not seem to be required for confirmation.     

基于MR血管成像数据和快速原型技术建立类似于人颈内动脉虹吸段动脉瘤的犬模型

目的 建立载瘤动脉类似于人体颈内动脉虹吸段形态的犬动脉瘤模型.方法 用3.0 T MR行3维(3D)-时间飞跃(TOF)-MR血管成像(MRA)序列采集人头颅横断面医学数字图像通讯(DICOM)格式图像,导人Materialise Mimics和Pro-E软件重组,做出带孔管状3D数字模型.根据该文件利用快速原型技术制作出 TangoPlus材料的实体模型并硅胶涂层.分别将6只实验犬左侧颈总动脉远端和右侧颈总动脉近端结扎离断.将游离的左侧颈总动脉通过黑线牵引从下而上,游离的右侧颈总动脉从右剑左穿过模型,并从模型上的孔牵出.处理游离的双侧颈总动脉外膜后,行端侧吻合,得到形态类似于人颈内动脉虹吸段动脉瘤形态的动脉瘤模型.动物模型完成后即刻及1周MRA随访,1周行血管造影并置入测试支架测试.结果 6只犬均成功建立了形态类似于人颈内动脉虹吸段动脉瘤的动脉瘤模型.MRA显示6只犬的载瘤动脉通畅,显影良好.置人支架后1只犬死亡;5只术后1个月随访,模型内血管均通畅,其中3只弯曲处血管变扁,2 只无明显管腔形态改变.结论 制作的模型弯曲血管与人体颈内动脉虹吸段形态高度相似,可作为颅内神经介入材料及其输送系统的研究测试以及神经介入医师培训的工具.     

Use of single-slice thick slab phase-contrast angiography for the diagnosis of dural venous sinus thrombosis

The aim of this study was to examine the reliability of single-slice phase-contrast angiography (SSPCA) as a rapid technique for the investigation of suspected dural venous sinus occlusion. Images were obtained on 25 normal volunteers to document the accuracy of SSPCA in the demonstration of slow flow states. Normal volunteers were imaged using sagittal and coronal SSPCA (slice thickness 13 cm, matrix 256 × 256, TR 14 ms, TE 7 ms, flip angle 20 °, peak velocity encoding rate 30 cm/s). Sinus patency and flow rate were confirmed by measurement of flow in the superior sagittal and transverse sinuses using quantified single-slice phase difference images. Imaging was performed in 50 patients undergoing routine brain scans in order to determine the optimal slice orientation for clinical use. Twenty-one patients with suspected dural venous sinus thrombosis were also investigated with SSPCA and the diagnosis confirmed by one or more alternative imaging techniques. Imaging time was 29 s per acquisition and image quality was good in all cases. Variations in dural sinus patency and flow in normal volunteers were accurately predicted by SSPCA (kappa = 0.92). Use of a single angulated slice (130 mm thick, para-sagittal image angled 30 ° towards coronal and 30 ° towards transverse) provided sufficient separation of right- and left-sided venous structures to allow use of a single projection. The presence and extent of sinus occlusions in 14 patients and the absence of thrombosis in 7 were accurately identified by SSPCA. Sensitivity and specificity in this limited study were both 100 %. The SSPCA technique takes less than 30 s and provides a reliable and rapid technique for the diagnosis of dural venous sinus thrombosis. Received: 10 July 1998; Revision received: 16 November 1998; Accepted: 11 January 1999     

Serial MRI of a mycotic aneurysm of the cavernous carotid artery

Cerebral mycotic or infective aneurysms are a rare complication of infectious illness, and such aneurysms of the intracavernous portion of the internal carotid artery are rare. They have been described as a consequence of cavernous sinus infection in an immunocompromised host, but not previously in a renal transplant recipient. We present such a case with serial MRI showing progression from arterial narrowing to aneurysm formation. Transcranial Doppler sonography of the middle cerebral artery showed distal asymptomatic embolisation from the aneurysm.     

Sigmoid and transverse sinus thrombosis after closed head injury presenting with unilateral hearing loss

Sinus thrombosis has rarely been associated with closed head injury; more often, thrombosis of the sigmoid or transverse sinus is caused by otogenic inflammations or tumours, or occurs during pregnancy. Symptoms are frequently vague, while untreated thrombus progression may be fatal due to venous congestion and infarction. We report a 32-year-old man presenting with right hearing loss, tinnitus and headache 2 days after a closed head injury. Neurological examination showed no additional abnormality. The EEG showed focal bifrontal slowing. CT revealed a fracture of the occipital bone. MRI and MRA demonstrated complete thrombosis of the right sigmoid and transverse sinuses. After 2 weeks of intravenous heparin therapy followed by warfarin, the patient's hearing improved and MRI and MRA showed complete recanalisation of the sigmoid and transverse sinuses. Venous sinus thrombosis can be an undetected sequel to head injury. Appropriate imaging studies should be carried out to enable therapy to be started as soon as possible.     

CT血管成像诊断破入蝶窦的颈内动脉创伤性假性动脉瘤

目的 评价颅脑CTA在海绵窦段颈内动脉创伤性假性动脉瘤中的诊断价值.方法 对7例经DSA证实的颈内动脉海绵窦段创伤性假性动脉瘤患者的CTA联合应用VR、MIP、MPR、CPR后处理技术及临床资料进行回顾性分析.结果 7例CTA均表现为蝶窦内不规则软组织影与海绵窦段颈内动脉同步均匀强化并与其沟通,边界清晰,边缘不规则,病变大小自3 mm×2 mm×1 mm～33 mm×30 mm×27 mm.周边为动脉期不强化的软组织影,邻近蝶窦壁骨折、缺损.6例病变位于海绵窦段颈内动脉前突段,1例位于游离段.7例破口均位于颈内动脉内壁或前内壁.多种后处理技术联合应用可明确显示病变与蝶窦腔、蝶窦骨质及邻近血管的空间关系.结论 颅脑CTA检查对破入蝶窦的海绵窦段颈内动脉创伤性假性动脉瘤可明确诊断;VR、MIP、MPR、CPR后处理技术联合应用可明确蝶窦壁骨折和颈内动脉破口的位置、范围及其二者的关系.

Abstract：

Objective To investigate diagnostic value of CTA for traumatic pseudoaneurysms (TPA) in the cavernous segment of the internal carotid artery (ICA) when they rupture into the sphenoid sinus. Methods CTA of 7 patients with TPA in the cavernous segments of ICA verified by DSA were retrospectively analyzed. All the patients were performed CTA scanning. The post-processing techniques included VR,MIP,MPR, and CPR. Results All the CTA images of 7 patients showed irregular mass in the sphenoid sinus with obviously enhancement in the same phase to ICA, which communicating with ICA in wide base. The peripheral area of the mass showed no enhancement. The size varied from 3 mm × 2 mm × 1 mm to 33 mm × 30 mm × 27 mm. The adjacent lateral wall of sphenoid sinus showed fractures in all cases. TPA located at anterior-knee segments of cavernous ICA in 6 cases, and cavernous free segment in 1 case. All the disruptions were found at medial or anterior medial wall of ICA. Conclusions Cranial CTA is the effective non-invasive method for diagnosing TPA in the cavernous segment of ICA when they rupture into sphenoid sinus. Combined using of VR, MIP, MPR, and CPR can delineate the location and size of the sphenoid wall fracture and the ICA rupture, which help to clarify the anatomical relationship between them.     

Development of a posterior cerebral artery aneurysm subsequent to occlusion of the contralateral internal carotid artery for giant cavernous aneurysm

We report a case of a patient who developed a left posterior cerebral artery aneurysm 5 years after balloon occlusion of the right internal carotid artery for a giant cavernous aneurysm. The location of the new aneurysm was outside of the primary collateral pathways to the contralateral, proximally occluded, anterior circulation, illustrating the complexity of hemodynamic factors contributing to the development of intracranial saccular aneurysms. The appearance of an aneurysm in this setting supports the hypothesis that degenerative factors and hemodynamic stresses are important in the etiology of intracranial aneurysms.     

Evaluation of the carotid artery bifurcation: comparison of magnetic resonance angiography and digital subtraction arch aortography

Summary Thirty-four carotid artery bifurcations were examined using both magnetic resonance angiography (MRA) and digital subtraction arch aortography to determine their accuracy when compared to selective carotid angiography. The sensitivity of MRA was 73% and its specificity was 91% when compared with selective carotid angiography. The sensitivity of arch aortography was 27% and its specificity was 100%.