Value of DSA in the Diagnostic Workup of Pulsatile Tinnitus

ObjectivesPulsatile tinnitus (PT) is a rare complaint, but can be a symptom of life-threatening disease. It is often caused by vascular pathologies, e.g. dural arteriovenous fistula (dAVF), arteriovenous malformation (AVM) or vascularized tumors. The current diagnostic pathway includes clinical examination, cranial MRI and additional DSA. The aim of this study was to evaluate the diagnostic impact of DSA in the diagnostic workup of patients with PT in comparison to MRI alone.MethodsRetrospectively, 54 consecutive patients with pulsatile tinnitus were evaluated. All patients had a diagnostic workup including cranial MRI and DSA. MRI examinations were blinded to the results of DSA and retrospectively analyzed in consensus by two experienced neuroradiologists. The MR-examinations were evaluated for each performed sequence separately: time-of-flight-angiography, ce-MRA, T2, ce-T1-sequence and ce-T1-sequence with fat saturation.Results37 of the 54 patients revealed a pathology explaining PT on MRI, which was detected by the readers in 100% and proofed by means of DSA. 24 dAVF, four paraganglioma, two AVM and seven more pathologies were described. All patients without pathology on MRI did also not show any pathology in DSA.ConclusionsMR imaging is sufficient to exclude pathology in patients with pulsatile tinnitus.     

脑发育性静脉畸形9例临床影像特征分析及文献复习

目的:研究脑发育性静脉畸形(Cerebral Developmental Venous Anomalies,CDVA)临床及影像学特征及复习CDVA文献。方法:回顾性收集了自2011年11月至2014年3月我科确诊的9例CDVA的病人,对其临床特征、影像学检查方法包括电子计算机断层扫描(Computed Tomography,CT)、核磁共振成像(Magnetic Resonance Imaging,MRI)、数字减影血管造影(Digital Subtraction Angiography,DSA)及特征进行分析并对相关文献进行复习。结果:(1)临床症状:9例病人的临床症状包括头晕4例(4/9)、头痛4例(4/9)、恶心不适2例(2/9)、站立不稳1例((1/9)、小脑出血史1例(1/9)、眼部症状行眼科检查偶然发现小脑CDVA1例(1/9);(2)病变部位:病变位于幕上4例(4/9);幕下5例(5/9);(3)影像学检查:9例病人中,6例行CT平扫或增强扫描(3例平扫,3例平扫+增强);4例行MRI(1例平扫,3例平扫+增强);3例行DSA检查;(4)影像学特点:CT增强及重建、MRI的T1WI增强、SWI、MRA及DSA静脉期像均可显示出髓静脉及其形成的特征性"海蛇头"征象和其引流静脉。结论:CT、MRI、DSA影像学方法均可用于CDVA的诊断,在临床实践中需根据需要优化选择联合应用。     

Proposed local diagnostic reference levels in angiography and interventional neuroradiology and a preliminary analysis according to the complexity of the procedures

The aim of this study was to propose local diagnostic reference levels (DRL) for exposure to radiation during diagnostic procedures and neuroradiological interventions such as cerebral angiography and embolisation of cerebral aneurysms (intra-cranial aneurysms and arteriovenous malformations). Hospitals should adopt the national DRLs for use locally or establish their own DRLs based on local practice, if sufficient local data are available.For this purpose we studied a sample of 113 cerebral angiography procedures and 82 embolisations of cerebral aneurysms. The data recorded included the kerma-area product (KAP), the fluoroscopy time and the number of frames for each procedure: third quartiles from the total dosimetric databank were calculated and proposed as provisional local DRL. Since the complexity of a procedure must be taken into account when evaluating the radiation dose, in the case of embolisation of aneurysms (intra-cranial), in this initial phase we assessed whether the complexity of the embolisation procedure is related to the size of the aneurysm and/or its site. We, therefore, re-calculated the DRL for only intra-cranial aneurysms, leaving aside the arteriovenous malformations. Considering that the DRL calculated for all the therapeutic procedures are similar to those calculated considering only intra-cranial aneurysms, at the moment we propose, besides the DRL for cerebral angiography, a single DRL for all interventional procedures, even when the clinical pictures are very different. Local preliminary DRLs were proposed as follows: 180 Gy cm², 12 min and 317 frames for cerebral angiography and 487 Gy cm², 46 min and 717 frames for interventional procedures (intra-cranial aneurysms and arteriovenous malformations).     

Interventional neuroradiology.

A wide variety of diseases affecting the central nervous system and head and neck can be treated using interventional neuroradiologic techniques. These new treatments have depended on advances in radiologic imaging, catheter technology, and the development of new embolic agents. These procedures may be an adjunct to other therapy, palliative or curative. Diseases for which interventional neuroradiologic techniques have been major advances in treatment include cerebral aneurysms, vasospasm after subarachnoid hemorrhage, cerebral arteriovenous malformations, dural arteriovenous fistulas, dural sinus thrombosis, atherosclerosis, scalp arteriovenous fistulas, carotid-cavernous fistulas, and stroke. This field is rapidly evolving as advances are made in catheter technology and new embolic agents are developed.     

RASA1: variable phenotype with capillary and arteriovenous malformations

Capillary malformation-arteriovenous malformation (CM-AVM) is a newly discovered hereditary disorder. Its defining features are atypical cutaneous multifocal capillary malformations often in association with high-flow lesions: cutaneous, subcutaneous, intramuscular, intraosseous and cerebral arteriovenous malformations and arteriovenous fistulas. Some patients have Parkes Weber syndrome - a large congenital cutaneous vascular stain in an extremity, with bony and soft tissue hypertrophy and microscopic arteriovenous shunting. In the past, arteriovenous malformations and arteriovenous fistulas had been considered non-hereditary. A classical genetic approach was used to identify the locus. Candidate gene screening pinpointed mutations in RASA1 (p120-RASGAP) - a RasGTPase. RASA1 reverts active GTP-bound Ras into inactive GDP-bound form. Murine Rasa1 knockout and tetraploid-aggregated embryos with RNA interference exhibited abnormal vascular development. Lack of RASA1 activity caused inhibition of cell motility, possibly through p190-RhoGAP. Thus, RASA1 defects probably cause abnormal angiogenic remodeling of the primary capillary plexus that cannot be compensated for by other RasGAPs: RASA2, RASAL and NF1. Signaling pathways involving RASA1 might offer novel targets for treatment of high-flow vascular anomalies.     

多功能磁共振造影剂研究进展

磁共振成像技术因对人体无创、任意方向断层扫描三维图像且分辨率较高、提供形态与功能两方面诊断评价等突出优点,成为了临床上用于疾病诊断的重要手段之一。临床上使用磁共振造影剂可以提高成像的分辨率和灵敏度,提高图像质量,增强对比度和可读性。但是,各种成像技术由于实现原理不同,具有各自的优势和缺陷,靠传统单一的诊断模式无法提供疾病的全面信息,因而在对各种复杂疾病进行诊断时会受到一定的限制。因此,将磁共振成像与其他成像技术如CT成像、超声成像等联合起来使用,则可以达到优势互补的效果,能为疾病的临床诊断提供更快捷精确的信息,同时可将磁共振成像与各种治疗方式结合在一起,即开发基于磁共振成像的诊断治疗一体化试剂,以实现对疾病的即时治疗和实时监控。本文主要介绍了磁共振成像造影剂的原理和种类,并且综述了目前国内外在基于磁共振成像的多功能造影剂/诊疗制剂这一领域的研究进展,最后就未来可能的研究方向进行了展望。     

The use of digital subtraction angiography in diseases of the arteries of the pelvis and lower limbs

The diagnostic potentialities of digital subtraction angiography (DSA) in diseases of the pelvic arteries and lower limbs were studied. Intravenous (iv) and intraarterial (ia) DSA were performed in 613 patients, among them were patients with obliterating atherosclerosis and endarteritis, thromboembolism, aneurysms and arteriovenous fistulas. Iv DSA provided good information for the solution of therapeutic and tactical problems in pelvic, femoral and popliteal arterial lesions but in 16% of the cases it gave no opportunity to assess the status of the crural arteries. Ia DSA was shown to be no inferior to routine arteriography in the visualization of the lower limb arteries. This method is economical, well tolerated by patients, permits the intensification of examination of patients with acute and chronic arterial pathology. It can be employed under outpatient conditions and in the early postoperative period.     

Fractal dimension and vessel complexity in patients with cerebral arteriovenous malformations

The fractal dimension (FD) can be used as a measure for morphological complexity in biological systems. The aim of this study was to test the usefulness of this quantitative parameter in the context of cerebral vascular complexity. Fractal analysis was applied on ten patients with cerebral arteriovenous malformations (AVM) and ten healthy controls. Maximum intensity projections from Time-of-Flight MRI scans were analyzed using different measurements of FD, the Box-counting dimension, the Minkowski dimension and generalized dimensions evaluated by means of multifractal analysis. The physiological significance of this parameter was investigated by comparing values of FD first, with the maximum slope of contrast media transit obtained from dynamic contrast-enhanced MRI data and second, with the nidus size obtained from X-ray angiography data. We found that for all methods, the Box-counting dimension, the Minkowski dimension and the generalized dimensions FD was significantly higher in the hemisphere with AVM compared to the hemisphere without AVM indicating that FD is a sensitive parameter to capture vascular complexity. Furthermore we found a high correlation between FD and the maximum slope of contrast media transit and between FD and the size of the central nidus pointing out the physiological relevance of FD. The proposed method may therefore serve as an additional objective parameter, which can be assessed automatically and might assist in the complex workup of AVMs.     

A case of macrocephaly-cutis marmorata telangiectatica congenita and review of neuroradiologic features

Macrocephaly-cutis marmorata telangiectatica congenita (M-CMTC) is characterized by macrocephaly, cutis marmorata, capillary malformations, toe syndactily, joint laxity and pre-natal overgrowth. Cerebral abnormalities might also be seen. We reported cerebral magnetic resonance imaging (MRI) findings of a case with M-CMTC, who had giant atrial septal aneurysm and atrial septal defect. Cerebral alterations determined by MRI were bilateral prominent lateral ventricles, bilateral cortical dysplasia, cavum septi pellucidum cyst and calvarial hemangioma. At 17th day of his life he suddenly developed cardiorespiratory arrest and died.     

Comparative ultrasound and magnetic resonance diagnosis of fetal CNS malformations

The study was undertaken to optimize the diagnosis of fetal CNS and facial malformations, by using a complex of ultrasound (US) and magnetic resonance imaging (MRI) studies. A hundred and forty-four fetuses with suspected CNS and facial malformations were examined. The US study conducted by a specially developed protocol was supplemented by MRI (48 fetuses) also made by a specially developed protocol. Various fetal CNS malformations, such as neural tube defects, congenital endbrain malformations, cystic lesions, tumors, ventricular complex anomalies, defects of the face and eyes, multiple defects, including CNS and facial anomalies, were detected. With MRI, the diagnosis was changed in 33% of cases. The application of a complex of US and MRI studies enhances the efficiency of diagnosis of congenital CNS and facial malformations in the fetus. MRI in the diagnosis of fetal CNS and facial malformations has a number of advantages and should be used if there is some difficulty in establishing a diagnosis when an US study is performed.     

La stimulation électrique pallidale dans le traitement des mouvements anormaux : l’expérience montpelliéraine dans l’utilisation de l’imagerie fonctionnelle comme critères de sélection des patients

Magnetic resonance anatomical imaging gives to the practician an important set of criteria for selecting patients with dystonic and dyskinetic syndromes who can get benefice from a treatment by electrical deep brain stimulation. However, anatomical anomalies seen on MRI, whatever their number and morphological extension, do not reflect the effective (residual) functional activity of the corresponding structures. We describe, in this short report, the way how, in our experience, functional imaging techniques used for measuring cerebral perfusion and neurotransmission in Single Photon Emission Computerized Tomography (SPECT), cerebral metabolism in Positron Emission Tomography (PET) and motor neuroactivations in functional Magnetic Resonance Imaging (fMRI) are capable of progressively fulfil this deficiency.     

Bimodal paramagnetic and fluorescent liposomes for cellular and tumor magnetic resonance imaging

A novel bimodal fluorescent and paramagnetic liposome is described for cellular labeling. In this study, we show the synthesis of a novel gadolinium lipid, Gd.DOTA.DSA, designed for liposomal cell labeling and tumor imaging. Liposome formulations consisting of this lipid were optimized in order to allow for maximum cellular entry, and the optimized formulation was used to label HeLa cells in vitro. The efficiency of this novel bimodal Gd-liposome formulation for cell labeling was demonstrated using both fluorescence microscopy and magnetic resonance imaging (MRI). The uptake of Gd-liposomes into cells induced a marked reduction in their MRI T 1 relaxation times. Fluorescence microscopy provided concomitant proof of uptake and revealed liposome internalization into the cell cytosol. The optimized formulation was also found to exhibit minimal cytotoxicity and was shown to have capacity for plasmid DNA (pDNA) transfection. A further second novel neutral bimodal Gd-liposome is described for the labeling of xenograft tumors in vivo utilizing the enhanced permeation and retention effect (EPR). Balb/c nude mice were inoculated with IGROV-1 cells, and the resulting tumor was imaged by MRI using these in vivo Gd-liposomes formulated with low charge and a poly(ethylene glycol) (PEG) calyx for long systemic circulation. These Gd-liposomes which were less than 100 nm in size were shown to accumulate in tumor tissue by MRI, and this was also verified by fluorescence microscopy of histology samples. Our in vivo tumor imaging results demonstrate the effectiveness of MRI to observe passive targeting of long-term circulating liposomes to tumors in real time, and allow for MRI directed therapy, wherein the delivery of therapeutic genes and drugs to tumor sites can be monitored while therapeutic effects on tumor mass and/or size may be simultaneously observed, quantitated, and correlated.     

Use of magnetic resonance imaging for the evaluation of vascular malformations of the lower extremity

Vascular malformations are anatomically subdivided according to the predominant channel anomaly into either capillary, arterial, venous, lymphatic, or combinations. They can be further subdivided into high- or low-flow malformations. Any lesion that has an arterial component is considered a high-flow malformation. Once the diagnosis of a vascular malformation is made, it is of paramount importance to define not only the flow characteristics but also the full range of extension, because the prognosis and appropriate treatment vary substantially for each type of anomaly. The two most useful noninvasive imaging techniques for assessing vascular malformations are magnetic resonance imaging (MRI) and ultrasonography. The aim of this review is to give surgeons involved in treating patients with vascular malformations an opportunity to gain some background on MRI scans when assessing vascular malformations. Although MRI is a powerful modality for assessing vascular malformations, we will also discuss some of the limitations of MRI. We further suggest a diagnostic flow chart developed on the basis of MRI features designed to help determine the composition of a vascular birthmark when intervention is anticipated.     

The role of magnetic resonance imaging in the management of vascular malformations of the trunk and extremities

Vascular malformations can usually be diagnosed on clinical grounds. They have a well-defined appearance on magnetic resonance imaging, which can effectively determine their tissue and flow characteristics. However, the role of cross-sectional imaging in the management of vascular malformations is not well defined. Most reviews suggest that magnetic resonance imaging should be reserved for cases in which the extent of the lesion cannot be estimated on physical examination. However, to date no group has compared the accuracy of physical examination alone to that of magnetic resonance imaging in determining this extent. A review was performed of all the patients evaluated for vascular malformations at the New York University Trunk and Extremity Vascular Anomalies Conference between July of 1994 and August of 1999. Patients who underwent magnetic resonance evaluation at other institutions and whose images were not available for review were excluded. All study patients either underwent magnetic resonance imaging examination at New York University Medical Center or had outside films reviewed at the center. The physical examination findings were compared with the magnetic resonance findings and the surgeon and radiologist made a joint decision about whether there was a correlation between the magnetic resonance and physical examination findings. Fifty-eight patients met the study criteria, 44 (76 percent) of whom were found to have more extensive disease on magnetic resonance examination than appreciated on physical examination. Of the 51 patients with low-flow vascular malformations (venous vascular malformations, lymphatic malformations, and capillary malformations), 39 (76 percent) had more extensive disease on magnetic resonance examination than on physical examination. Of the seven patients with high-flow arteriovenous malformations, five had more extensive disease on magnetic resonance. In all of the 44 patients whose magnetic resonance imaging findings did not correlate with those of the physical examination, therapeutic decision making was affected. Contrary to the conventional wisdom of published reviews, physical examination findings significantly underestimated the extent of vascular malformations in the majority of cases. Magnetic resonance imaging should be performed in all patients with vascular malformations of the trunk and extremities before therapy is planned. In an age when physicians are asked to justify their decisions, especially where the use of expensive diagnostic modalities is concerned, the situations in which these tests are indispensable must be clearly defined or else patients will be denied access to them.     

Potentialities of magnetic resonance imaging in the complex of prenatal radiation diagnosis of fetal malformations

The purpose of the study was to investigate the potentialities of magnetic resonance imaging (MRI) in the complex of prenatal radiation diagnosis of fetal malformations. Twenty-eight female patients with suspected fetal malformations were examined. Ultrasound study was supplemented by MRI according to a specially developed protocol. Various fetal CNS malformations were diagnosed. These included the Arnold-Chiari syndrome, the Dandy-Walker syndrome, occlusive hydrocephaly, lobular holoprosencephaly, porencephaly, diaphragmatic hernias, anomalies of the abdomen and retroperitoneal space, as well as anomalies of facial structures, including median clefts, and dacryocystocele. The use of MRI in the complex prenatal radiation diagnosis makes it possible to visualize fetal malformation more clearly, contributes to the more adequate prediction of the outcome of pregnancy and to the choice of a management policy for a female patient.     

Coexistence of intradural spinal arteriovenous malformation and associated developmental anomalies - report of two cases

Spinal arteriovenous malformations (AVM) have been devided into dural (Type I), intramedullary glomus (Type II), juvenile (Type III), and perimedullary direct arteriovenous fistulae (Type IV). AVMs are usually associated with subacute myelopathy in what has been known as Foix-Alajouanine syndrome. We presented two patients with two intradural spinal arteriovenous malformations associated in what we call Foix-Alajouanine syndrome. The both patient developed acute back pain and paresthesias, followed by paraplegia and incontinence. The clinical status of one patient has been improved after particle embolization for a 17 years when he deteriorated up to paraplegia after spinal angiography for follow up. Clinical status in another patient deteriorated, because particle emoblisation cannot be performed due to very descrete presentation of the feeding artery. Extensive neuroradiological examination in both patients revealed coexistence of numerous associated developmental anomalies in both patients. We conclude that arteriovenous malformations occasionally are associated with other vascular and nonvascular developmental anomalies elsewhere in the body. These findings rise attention about keep in mind the suspicion of mutual etiopathogenesis and congenital origin of these anomalies. Early timing of the diagnostic and therapeutic interventiosn are stressed to prevent or delay irreversible ishaemic myellopathy or haemorrhage. For the definitive diagnosis of spinal arteriovenous malformations and evaluation of its occlusion grade after the therapy spinal angiography is needed     

Merging computational fluid dynamics and 4D Flow MRI using proper orthogonal decomposition and ridge regression

Time resolved phase-contrast magnetic resonance imaging 4D-PCMR (also called 4D Flow MRI) data while capable of non-invasively measuring blood velocities, can be affected by acquisition noise, flow artifacts, and resolution limits. In this paper, we present a novel method for merging 4D Flow MRI with computational fluid dynamics (CFD) to address these limitations and to reconstruct de-noised, divergence-free high-resolution flow-fields. Proper orthogonal decomposition (POD) is used to construct the orthonormal basis of the local sampling of the space of all possible solutions to the flow equations both at the low-resolution level of the 4D Flow MRI grid and the high-level resolution of the CFD mesh. Low-resolution, de-noised flow is obtained by projecting in vivo 4D Flow MRI data onto the low-resolution basis vectors. Ridge regression is then used to reconstruct high-resolution de-noised divergence-free solution. The effects of 4D Flow MRI grid resolution, and noise levels on the resulting velocity fields are further investigated. A numerical phantom of the flow through a cerebral aneurysm was used to compare the results obtained using the POD method with those obtained with the state-of-the-art de-noising methods. At the 4D Flow MRI grid resolution, the POD method was shown to preserve the small flow structures better than the other methods, while eliminating noise. Furthermore, the method was shown to successfully reconstruct details at the CFD mesh resolution not discernible at the 4D Flow MRI grid resolution. This method will improve the accuracy of the clinically relevant flow-derived parameters, such as pressure gradients and wall shear stresses, computed from in vivo 4D Flow MRI data.     

髓周动静脉瘘（PMAVF）一例及文献复习

目的:探讨髓周动静脉瘘(perimedullary arteriovenous fistulas,PMAVF)的临床、影像学特征以及治疗方案的选择,以提高对该病的诊断水平。方法:报道1例PMAVF患者的临床诊治经过,并结合相关文献对PMAVF的临床、影像学特征和治疗方法进行总结。结果:1例表现为进行性下肢麻木伴无力的患者,并逐渐出现大小便失禁,胸腰段MRI示第9胸椎水平附近椎管内髓周血管明显迂曲扩张。行脊髓血管造影检查示右侧胸9肋间动脉发出的脊髓前动脉在胸12椎体水平通过分支供应的异常引流静脉走形于脊柱右侧。予Onyx胶栓塞引流静脉及瘘口,术后一年肌力恢复至4级左右。结论:PMAVF早期临床表现多不具有特异性,后逐渐出现进展性脊髓病变表现。脊髓MRI对提示PMAVF诊断具有重要作用,脊髓血管CTA和ceMRA有助术前判断供血动脉和瘘口位置。脊髓血管造影仍是诊断该病的金标准。手术切除和血管内治疗是治疗该病的主要方法。     

A novel transcutaneous vagus nerve stimulation leads to brainstem and cerebral activations measured by functional MRI]

BACKGROUND: Left cervical vagus nerve stimulation (VNS) using the implanted NeuroCybernetic Prosthesis (NCP) can reduce epileptic seizures and has recently been shown to give promising results for treating therapy-resistant depression. To address a disadvantage of this state-of-the-art VNS device, the use of an alternative transcutaneous electrical nerve stimulation technique, designed for muscular stimulation, was studied. Functional magnetic resonance imaging (MRI) has been used to test non-invasively access nerve structures associated with the vagus nerve system. The results and their impact are unsatisfying due to missing brainstem activations. These activations, however, are mandatory for reasoning, higher subcortical and cortical activations of vagus nerve structures. The objective of this study was to test a new parameter setting and a novel device for performing specific (well-controlled) transcutaneous VNS (tVNS) at the inner side of the tragus. This paper shows the feasibility of these and their potential for brainstem and cerebral activations as measured by blood oxygenation level dependent functional MRI (BOLD fMRI). MATERIALS AND METHODS: In total, four healthy male adults were scanned inside a 1.5-Tesla MR scanner while undergoing tVNS at the left tragus. We ensured that our newly developed tVNS stimulator was adapted to be an MR-safe stimulation device. In the experiment, cortical and brainstem representations during tVNS were compared to a baseline. RESULTS: A positive BOLD response was detected during stimulation in brain areas associated with higher order relay nuclei of vagal afferent pathways, respectively the left locus coeruleus, the thalamus (left > right), the left prefrontal cortex, the right and the left postcentral gyrus, the left posterior cingulated gyrus and the left insula. Deactivations were found in the right nucleus accumbens and the right cerebellar hemisphere. CONCLUSION: The method and device are feasible and appropriate for accessing cerebral vagus nerve structures, respectively. As functional patterns share features with fMRI BOLD, the effects previously studied with the NCP are discussed and new possibilities of tVNS are hypothesised.     

Superquadric modeling of cranial and cerebral shape and asymmetry

A new method for quantifying cranial and cerebral shape and asymmetry fits symmetric superquadric geometric models to three-dimensional coordinate measurements. Asymmetry is quantified as radial residuals of the surface data points from their best-fit superquadric models. Twenty human crania, 10 magnetic resonance imaging (MRI) exocranial surfaces, and 10 corresponding MRI cerebral surfaces as well as two infant head casts were digitized and modeled using superquadrics. Superquadric parameters have simple geometric interpretation, are very reproducible, and demonstrated statistically significant differences between crania of Amerindian ancestry and MRI exocranial surfaces of European ancestry used in this study. Superquadric models demonstrated strong congruence between MRI exocranial and cerebral surfaces. Typical asymmetry was 1-5 mm. Lastly, polar contour plots of radial residuals for head casts before and after orthotic cranioplasty demonstrated the efficacy of using superquadrics to quantify positional plagiocephaly and synostosis of infant crania.