Attila Kovacs

Noninvasive imaging after stent-assisted coiling of intracranial aneurysms: comparison of 3-T magnetic resonance imaging and 64-row multidetector computed tomography--a pilot study.

Background and Purpose: Follow-up imaging after stent-assisted coiling of intracranial aneurysms is limited by signal loss in the stented vessel segment using magnetic resonance imaging or by streak artifacts caused by aneurysm coils using multidetector computed tomography. In the search for a noninvasive surveillance in this condition, we propose a technique to minimize streak artifacts in multidetector computed tomography by gated data reconstruction and shifting the reconstruction window. Methods: The effect of the gated data acquisition in 64-row computed tomographic angiography (gCTA) on artifact reduction was evaluated in a preliminary phantom study and compared with nongated CTA, time-of-flight magnetic resonance angiography (TOF-MRA), and digital subtraction angiography (DSA). Scans were also obtained from 5 patients treated with stent-assisted coiling as part of their follow-up protocol. The length of impaired vessel segments (LIVS) in TOF-MRA and gCTA was compared and correlated with the stents length, the number of coils, and the packing density. The assessment of treatment outcome in TOF-MRA and gCTA was compared with DSA as the standard of reference. Results: The phantom study revealed 2 aspects: first, a distinct reduction of streak artifacts caused by coils using gated data acquisition; and second, because artifact orientation could be rotated systematically by shifting the reconstruction window, visualization of treated vessel segments was significantly superior in gCTA. In magnetic resonance imaging, all stented vessel segments were characterized by signal loss in both phantom and patients. The LIVS was 78% shorter in gCTA (4.86 ± 6.93 mm) compared with that in TOF-MRA (21.82 ± 7.47 mm, P < 0.01). In TOF-MRA, the LIVS correlated with the stents length, in gCTA with the number of coils. With regard to assessment of treatment outcome, gCTA and TOF-MRA correlated with DSA in 3 and in none of 5 patients, respectively. Conclusions: Gated CTA is a promising technique to reduce the amount of artifacts induced by stent-assisted intracranial coils. Image quality and assessment of treatment outcome in patients with stent-assisted coiling is superior compared with TOF-MRA.

Factors of influence upon overall survival in the treatment of intracranial MPNSTs. Review of the literature and report of a case

BackgroundIntracranial malignant peripheral nerve sheath tumors are rare entities that carry a poor prognosis. To date, there are no established therapeutic strategies for these tumors.MethodsWe review the present treatment modalities and present the current therapeutic dilemmas. We perform a statistical analysis to evaluate the prognostic factors for Overall Survival of these patients. Additionally, we present our experience with a 64-year-old man with a MPNST of the left cerebellopontine angle.ResultsTo our best knowledge, forty three patients with intracranial MPNSTs, including our case, have been published in the international literature. Our analysis showed gross total resection, radiotherapy and female gender to be beneficial prognostic factors of survival in the univariate analysis. Gross total resection was recognized as the only independent predictor of prolonged Overall Survival. In our case, we performed a gross total resection followed for the first time by stereotactically guided radiotherapy.ConclusionConsidering the results of the statistical analysis and the known advantages of the stereotaxy, we suggest aggressive surgery followed by stereotactically guided radiotherapy as therapy of choice.

Quantification of the magnetic resonance signal response to dynamic (C)O2‐enhanced imaging in the brain at 3 T: R*2 BOLD vs. balanced SSFP

To compare two magnetic resonance (MR) contrast mechanisms, R*2 BOLD and balanced SSFP, for the dynamic monitoring of the cerebral response to (C)O2 respiratory challenges.

Embolization of Varicocles: Pretreatment Sperm Motility Predicts Later Pregnancy in Partners of Infertile Men

PURPOSE To identify predictors of future pregnancy in partners of infertile men undergoing embolization of varicoceles. MATERIALS AND METHODS This study was conducted within local institutional review board guidelines, and written informed consent was obtained. In 223 clinically infertile men (age range, 18-50 years) with varicoceles and associated oligoteratoasthenospermia, endovascular embolization of the spermatic veins was performed with distal coil embolization and sclerotherapy. Additional anti-inflammatory treatment was initiated if required. Baseline clinical examination, semen specimen, and hormone level findings were compared to follow-up data. Posttreatment pregnancy rate of their healthy female partners was assessed with a standardized questionnaire. Unconditioned logistic regression was used to identify factors among all available clinical and laboratory data predicting treatment success (sired pregnancy during follow-up). RESULTS A total of 226 of 228 varicoceles in 223 patients were successfully treated. Resolution of varicoceles at clinical examination and ultrasonography (US) was observed in 206 patients (92.4%). Three-month follow-up semen analysis in these patients showed significant improvement in sperm motility (P < .001) and sperm count (P < .001); however, average values remained in the abnormal range (World Health Organization guidelines). In 173 patients, follow-up data were successfully obtained, with pregnancy reported in 45 (26%). Baseline sperm motility was identified as the only significant pretreatment factor (standardized regression coefficient beta = 3.285, t = 7.560, P = .006) predicting sired pregnancy. Hormone levels, clinical grading of varicoceles, Doppler US findings, and other semen parameters did not reach statistical significance. CONCLUSION Sperm motility prior to varicocele treatment in infertile men is an important predictor of later pregnancy.

Changes in the MR relaxation rate R2* induced by respiratory challenges at 3.0 T: a comparison of two quantification methods

The consistent determination of changes in the transverse relaxation rate R2* (ΔR2*) is essential for the mapping of the effect of hyperoxic and hypercapnic respiratory challenges, which enables the noninvasive assessment of blood oxygenation changes and vasoreactivity by MRI. The purpose of this study was to compare the performance of two different methods of ΔR2* quantification from dynamic multigradient‐echo data: (A) subtraction of R2* values calculated from monoexponential decay functions; and (B) computation of ΔR2* echo‐wise from signal intensity ratios. A group of healthy volunteers (n = 12) was investigated at 3.0 T, and the brain tissue response to carbogen and CO2–air inhalation was registered using a dynamic multigradient‐echo sequence with high temporal and spatial resolution. Results of the ΔR2* quantification obtained by the two methods were compared with respect to the quality of the voxel‐wise ΔR2* response, the number of responding voxels and the behaviour of the ‘global’ response of all voxels with significant R2* changes. For the two ΔR2* quantification methods, we found no differences in the temporal variation of the voxel‐wise ΔR2* responses or in the detection sensitivity. The maximum change in the ‘global’ response was slightly smaller when ΔR2* was derived from signal intensity ratios. In conclusion, this first methodological comparison shows that both ΔR2* quantifications, from monoexponential approximation as well as from signal intensity ratios, are applicable for the monitoring of R2* changes during respiratory challenges. Copyright

Pseudohypoxic brain swelling (postoperative intracranial hypotension-associated venous congestion) after spinal surgery: report of 2 cases.

BACKGROUND AND IMPORTANCE:Pseudohypoxic brain swelling is a rare event that may occur after uneventful brain surgery when subgaleal vacuum drainage is used. To date, such cases of unexpected postoperative disturbances of consciousness associated with radiological signs of basal ganglia, thalamic, brainstem, and cerebellum damage without any signs of vessel occlusion have not been known to occur after spinal surgery. CLINICAL PRESENTATION:We report for the first time on 2 patients presenting with a clinical and radiological picture of pseudohypoxic brain swelling after spinal surgery. In the first patient, bilateral basal ganglia damage occurred after thoracic spondylodiscitis surgery, manifested by epileptic seizures and coma lasting 1 week postoperatively with subsequent recovery. The second patient suffered basal ganglia and cerebellar and brainstem infarction after lumbar spondylodiscitis surgery, resulting in death. Because intraoperative cerebrospinal fluid leakage and use of postoperative epidural suction drainage with cerebrospinal fluid loss occurred in both cases, they are highly suspected to have potentially caused the complications. CONCLUSION:Pseudohypoxic brain swelling should be considered in patients with unexpected neurological deterioration after spinal surgery. It might be a form of postoperative intracranial hypotension-associated venous congestion, which should be distinguished from common postoperative cerebral ischemic events caused by arterial or venous occlusions.

The Enterprise Stent for the Treatment of Intracranial Aneurysms

AbstractBackground:Self-expanding microstents are typically placed before a wide-necked aneurysm is filled with coils. Alternatively, the stent may be placed at the end of the procedure, when the coil mass blocks or slows down the flow in the parent artery or a branching vessel.Patients and Methods:Between March 2007 and 2009, 20 aneurysms in 20 patients were treated with a total of 21 Enterprise stents. Nine aneurysms had reopened after coiling, eleven aneurysms were primarily treated, seven after acute subarachnoid hemorrhage. Eight aneurysms were primarily filled with coils and the stent was placed when the flow in the parent or a branching artery was blocked or slowed down. In four of these cases in which secondary stenting was considered an option in advance, the “artery at risk” was initially catheterized with a microcatheter.Results:Stent placement was successful in 19 aneurysms. In a reopened basilar tip aneurysm, Y-like stent placement through a Neuroform stent failed. With secondary stent placement (n = 8), all affected vessels could be safely reopened. None of these patients suffered from transient or permanent neurologic deficits. Using the jailing technique, it was possible to place two parallel stents in the internal carotid artery and posterior cerebral artery (PCA) in a reopened wide-necked PCA aneurysm.Conclusion:Apart from the primary use of the Enterprise stent in wide-necked aneurysm secondary stenting after coiling is a feasible technique to reopen occluded parent or branching arteries. Initial microcatheter placement in the artery which is at risk to get occluded when filling the aneurysm is a valuable option.ZusammenfassungHintergrund:Selbstexpandierende Mikrostents werden typischerweise platziert, bevor weithalsige Aneurysmen mit Platinspiralen gefüllt werden. Alternativ kann der Stent am Ende der Untersuchung platziert werden, wenn der Fluss im Trägergefäß oder in einem größeren abgehenden Gefäß blockiert wird oder abnimmt. Patienten und Methodik:Zwischen März 2007 und 2009 wurden 20 Aneurysmen bei 20 Patienten mit insgesamt 21 Enterprise- Stents versorgt. Neun Aneurysmen waren wiedereröffnet, elf Aneurysmen wurden primär behandelt, sieben davon nach frischer Subarachnoidalblutung. Acht Aneurysmen wurden primär mit Platinspiralen gefüllt, und der Stent wurde platziert, nachdem der Fluss im Trägergefäß oder in einem größeren Ast blockiert wurde oder abnahm. Bei vier dieser Patienten wurde die verschlussgefährdete Arterie primär mit einem Mikrokatheter markiert.Ergebnisse:Der Stent wurde bei 19 Patienten an der gewünschten Position freigesetzt. Bei einem Patienten misslang eine Y-förmige Stentimplantation über einen Neuroform-Stent mit Jailing des Basilariskopf-Aneurysmarests. Nach sekundärer Stentimplantation wurden alle Gefäße wiedereröffnet, kein Patient erlitt ein transientes oder permanentes neurologisches Defizit. Mit Hilfe der Jailing-Technik war es in einem Fall eines weithalsigen Aneurysmarezidivs der A. communicans posterior möglich, Stents parallel von der A. carotis interna in die A. cerebri media und die A. cerebri posterior zu platzieren.Schlussfolgerung:Neben der primären Stentimplantation vor Coiling ist die sekundäre Stentimplantation nach Coiling eine alternative Technik, um verschlossene Gefäße wiederzueröffnen. Zudem können verschlussgefährdete Arterien primär mit einem Mikrokatheter markiert werden.

Reversible multifocal leukoencephalopathy associated with a nocturnal blood pressure non-dipper pattern

Abstract The majority of cases of leukoencephalopathy related to hypertensive crisis show brain lesions predominantly in the posterior lobe. Such cases are usually classified as reversible posterior leukoencephalopathy syndrome (RPLS). A multifocal distribution pattern is also possible, but occurs seldom. Here we report two patients with extensive white matter lesions that affect the entire brain, related to hypertensive crisis associated with a non-dipper pattern of blood pressure during the night as well as renal dysfunction. This nocturnal blood pressure abnormality may be relevant for the distribution pattern of cerebral white matter lesions and underlines the concept that in these cases a 24-h ambulatory blood pressure monitoring is needed.