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Editorial

Vertebrobasilar dissections

Giuseppe Lanzino

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Kenichi Sato, Karel G. TerBrugge and Timo Krings

Object

Spinal dural arteriovenous fistulas (SDAVFs) consist of a shunt with converging feeding vessels arising from radiculomeningeal arteries and draining retrogradely via a radicular vein into the perimedullary veins, thereby causing progressive myelopathy due to venous hypertension in the spinal cord. The purpose of this study was to evaluate the hypothesis that the obstruction of radicular venous outlets could be an additional factor inducing symptomatic venous hypertension due to a decreased outflow in SDAVFs.

Methods

The authors compared the clinical and imaging findings in patients with asymptomatic SDAVFs identified incidentally at the upper thoracic region with the findings in symptomatic patients who harbored SDAVFs at the same level.

Results

All symptomatic patients presented with medullary dysfunction. The mean age of patients with asymptomatic SDAVF was 51.5 years, approximately 10 years younger than the patients with symptomatic SDAVF (64.1 years old). Despite the existence of dilated perimedullary vessels in the dorsal side of the spinal cord in all patients, the spinal cord edema seen in symptomatic patients was not detected on the MR images obtained in patients with asymptomatic SDAVF. The spinal angiograms of the asymptomatic patients distinctively demonstrated early radicular venous outflow from affected perimedullary veins to the extradural venous plexus as a potential alternate route for the venous hypertension to be released.

Conclusions

Obstruction of the radicular venous outflow could be an important factor in inducing spinal congestive edema due to venous hypertension, as well as subsequent clinical symptoms of SDAVFs.

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Daipayan Guha, Tim-Rasmus Kiehl, Timo Krings and Taufik A. Valiante

Schwannomas of the brain parenchyma are extremely rare, occurring mostly in children and young adults. Fewer than 50 cases have been reported in the English-language literature. Isolated temporal lobe epilepsy is a rare presentation of intracerebral schwannomas, with only 2 reported cases. The authors present the case of a 51-year-old woman with a 4-year history of medication-refractory seizures, which were localized on electroencephalography to the right temporal lobe. Magnetic resonance imaging identified a mildly space-occupying, T2 hyperintense, and inhomogeneously enhancing mass in her left mesial temporal lobe. Histological, immunohistochemical, and electron microscopy examinations of the surgical specimen established a diagnosis of intracerebral schwannoma. Accurate diagnosis of intracerebral schwannomas is essential, particularly in younger patients, given the lesions' nature, amenity to resection, favorable long-term prognosis, and broad radiological differential. The etiology of these lesions remains unknown, and multiple proposed theories are reviewed.

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Jai Jai Shiva Shankar, Karel terBrugge and Timo Krings

Synchronous multiplicity of cranial and spinal dural arteriovenous fistulas (DAVFs) is known but uncommon. The authors report on a patient with the unusual finding of multiple cranial and multiple separate spinal DAVFs. The patient initially presented with vague visual symptoms in 2004. A cranial DAVF was identified along the left transverse sinus with cortical venous reflux and another DAVF was identified along the posterior part of the superior sagittal sinus with no cortical venous reflux. The first DAVF was treated both endovascularly and surgically and the second was left untreated. The follow-up angiogram showed multiple spinal DAVFs at the levels of C-1, C-2, and C-6 on the left side and at the C-3 level on the right side along with another cranial DAVF along the anterior part of the superior sagittal sinus with cortical venous reflux. A retrospective analysis of the digital subtraction angiogram and MR images suggested that the cervical spinal DAVFs were already present in 2004 (6 years previously). Multiple DAVFs, although rare, do exist and it is important to look for any evidence of their presence when evaluating patients with symptoms suggestive of arteriovenous fistulas.

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Juan Pablo Cruz, Rene van Dijk, Timo Krings and Ronit Agid

Dural arteriovenous fistulas (DAVFs) of the cavernous sinus are acquired arteriovenous shunts between the dural branches of the internal and external carotid arteries and the cavernous sinus. These fistulas may present with cortical venous reflux, but more commonly drain antegradely toward the superior ophthalmic vein (SOV). Transvenous embolization is the most common endovascular treatment, but in some cases transvenous access to the compartment of the shunt may not be possible. In cases with no corticovenous reflux, manual compression of the SOV is an excellent alternative treatment, which is well known but rarely reported in the literature. The authors describe a series of 3 cavernous DAVFs with anterior drainage treated successfully by intermittent manual compression of the SOV.

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Guillaume Saliou, Peter Dirks, Lee-Anne Slater and Timo Krings

OBJECTIVE

The etiology of jugular bulb stenosis (JBS) or occlusion in the context of vein of Galen aneurysmal malformations (VGAMs) is unknown. It can lead to decompensation of a lesion that was previously clinically stable. The aim of this study was to describe the natural history of JBS or occlusion in VGAM and to determine whether there is an association with bony remodeling of the jugular foramina.

METHODS

The authors identified all cases of JBS greater than 70% bilaterally involving patients seen at The Hospital for Sick Children between January 2007 and June 2014. The foramen diameters were measured on sagittal CT imaging, on a slice passing at the level of the jugular vein. The jugular foramen diameters were also compared to measurements obtained in a matched population of the same age group who had no VGAM and had undergone cerebral CT for a reason other than vascular disease.

RESULTS

Eight patients (6 male and 2 female) with bilateral JBS were included in this series. The median duration of clinical follow-up was 2.5 years (IQR 1.7–4.2 years). JBS was associated with bony narrowing the jugular foramina in 7 of the 8 patients over time. Between 1 and 2 years of age, patients with a VGAM demonstrated jugular foramen narrowing in comparison with a matched population (p = 0.015).

CONCLUSIONS

Jugular bulb stenosis or occlusion in VGAM may be associated with narrowing of the jugular foramina. These conditions seem to have a male predominance. If treatment is required, bony narrowing of the jugular foramina should be taken into account when deciding whether angioplasty and stent placement or surgical bypass might be appropriate therapeutic options.

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Sasikhan Geibprasert, Sirintara Pongpech, Pakorn Jiarakongmun and Timo Krings

Spinal dural arteriovenous fistulas (DAVFs) are the spinal vascular malformations that are encountered most often, and they are usually encountered in the lower thoracic region. Cervical spine DAVFs are exceedingly rare and may be difficult to differentiate from radicular arteriovenous malformations, epidural arteriovenous shunts, or perimedullary AVFs. Typical angiographic findings in spinal DAVFs include a slow-flow shunt with converging feeding vessels from radiculomeningeal arteries draining via a radicular vein centripetally into perimedullary veins. The MR imaging findings such as spinal cord edema and perimedullary dilated vessels may be used to direct the spinal angiography that is needed to localize and classify the shunt. When the shunt is distant from the pathological imaging findings, the diagnosis may be difficult to establish, especially when the shunt is present at an atypical location such as the cervical spine. The authors present the case of a 51-year-old man presenting with lower thoracic and conus medullaris congestive edema due to a cervical spine DAVF that was located at the C-5 level. Transarterial embolization with N-butyl cyanoacrylate closed the proximal vein and completely obliterated the fistula. Clinical and imaging follow-up confirmed occlusion of the fistula, with improvement in clinical symptoms.

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Dittapong Songsaeng, Sasikhan Geibprasert, Karel G. ter Brugge, Robert Willinsky, Michael Tymianski and Timo Krings

Object

The goal was to investigate whether morphological features of aneurysms can be identified that determine initial success and recurrence rates of coiled aneurysms of the basilar artery tip, the posterior communicating artery (PCoA), and the anterior communicating artery.

Methods

The authors evaluated 202 aneurysms in connection with their pretreatment morphological features including size, neck-to-dome ratio, angulation of the aneurysm in relation to the parent artery, orientation of the aneurysm dome, and associated anatomical variations. The mean follow-up was 19 months (range 6–96 months) after endovascular coil occlusion. Using multivariate logistic regression, probabilities for initial complete occlusion and long-term stability of the treatment were calculated.

Results

Recanalization occurred in 49 of 202 cases. Favorable factors for long-term stability included small aneurysms with small necks. However, additional factors related to local hemodynamic forces could be identified for the different aneurysm locations, which may influence initial success rates and long-term stability of aneurysm treatment with endovascular coiling. These factors were a medial dome orientation and a symmetrical disposition of both A1 segments (for the anterior communicating artery), a posteroinferior dome orientation and a small-size PCoA (for the PCoA), and a cranial symmetrical fusion (for the basilar artery tip).

Conclusions

A detailed pretreatment analysis of morphological features of aneurysms may help to determine those aneurysms that are more prone to recurrence, which could add to the treatment decision and the follow-up algorithm.

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Dittapong Songsaeng, Kittipong Srivatanakul, Timo Krings, Sasikhan Geibprasert, Augustin Ozanne and Pierre Lasjaunias

Object

The purpose of this study is to analyze the clinical presentation, morphological characteristics, angio-architecture, and outcome of vertebrobasilar dissection (VBD) in the pediatric population.

Methods

The authors retrospectively reviewed 29 consecutive cases involving children younger than 16 years of age who were diagnosed with symptomatic VBDs. Data were gathered with respect to the patient's age, sex, clinical history, associated underlying disease, and symptoms (headache, vertigo) as well as the location of the dissection and the imaging appearance.

Results

The patients' mean age was 8.24 years (range 2 months–15 years). There was an overall 3:1 male predominance, although among children older than 8 years, girls and boys were similarly affected. Hemorrhagic dissections occurred in 10 of 29 cases. In nonhemorrhagic dissections, stroke occurred in 16 cases, with the most common presenting symptoms being headaches and vertigo; in the other 3 cases, mass effect due to a chronic dissecting aneurysm was present. In 7 children an underlying vessel wall disease was found. The location of the dissection was extradural in 11 cases and intradural in the remainder. There was no preference with respect to side. The basilar artery was affected in 9 patients.

Conclusions

The imaging appearance and clinical presentation of symptomatic VBDs in the pediatric population differs from that in adults. Boys are more often affected, especially at younger ages, and hemorrhagic presentation is more common, presumably owing to the fact that the basilar artery is more commonly involved. Depending on the pathogenetic mechanism underlying the dissection, different clinical symptoms will evolve, necessitating individually tailored treatment.

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Long Chen, Ivanna Yau, Gabrielle deVeber, Peter Dirks, Derek Armstrong and Timo Krings

Clinical and imaging manifestations of the so-called partially thrombosed aneurysm (PTA) are different from those of the classic intracranial saccular aneurysm. Given some of their peculiar imaging features, it had been hypothesized that some PTAs occur due to repeated intramural hemorrhages. The authors present a case of PTA that evolved from an acute dissecting aneurysm as shown by serial imaging. A previously healthy 5-year-old boy had a sudden onset of left hemiparesis. Initial MRI sequences showed a perforating vessel infarction in the right basal ganglia area secondary to an acute distal middle cerebral artery (MCA) dissection as demonstrated on conventional angiography. Conservative management with close observation of this dissection was chosen, and serial MRI studies revealed layering of blood of various ages within the wall of an aneurysmal outpouching of the MCA, thereby leading to the imaging appearance of a PTA. The findings in this case indicate that some PTAs may be caused by repeated or chronic dissections, with blood entering the wall through an endothelial defect. Understanding the pathological mechanism underlying the formation of these aneurysms will help inform appropriate treatment strategies.