Despite extensive imaging, a source of bleeding is often not evident during the evaluation of patients with superficial siderosis (SS) of the central nervous system. An intraspinal fluid-filled collection of variable dimensions is frequently seen on spine MR imaging in patients with idiopathic SS. A similar finding has also been reported in patients with craniospinal hypotension. This review discusses the role of multitechnique imaging in the work-up of patients with SS and focuses on recent developments.
]]>The goal of this article is to provide consensus recommendations for reporting standards, terminology, and written definitions when reporting on the radiological evaluation and endovascular treatment of intracranial, cerebral aneurysms. These criteria can be used to design clinical trials, to provide uniformity of definitions for appropriate selection and stratification of patients, and to allow analysis and meta-analysis of reported data.
This article was written under the auspices of the Joint Writing Group of the Technology Assessment Committee, Society of NeuroInterventional Surgery, Society of Interventional Radiology; Joint Section on Cerebrovascular Neurosurgery of the American Association of Neurological Surgeons and Congress of Neurological Surgeons; and Section of Stroke and Interventional Neurology of the American Academy of Neurology. A computerized search of the National Library of Medicine database of literature (PubMed) from January 1991 to December 2007 was conducted with the goal to identify published endovascular cerebrovascular interventional data about the assessment and endovascular treatment of cerebral aneurysms useful as benchmarks for quality assessment. We sought to identify those risk adjustment variables that affect the likelihood of success and complications. This article offers the rationale for different clinical and technical considerations that may be important during the design of clinical trials for endovascular treatment of cerebral aneurysms. Included in this guidance article are suggestions for uniform reporting standards for such trials. These definitions and standards are primarily intended for research purposes; however, they should also be helpful in clinical practice and applicable to all publications.
The evaluation and treatment of brain aneurysms often involve multiple medical specialties. Recent reviews by the American Heart Association have surveyed the medical literature to develop guidelines for the clinical management of ruptured and unruptured cerebral aneurysms. Despite efforts to synthesize existing knowledge on cerebral aneurysm evaluation and treatment, significant inconsistencies remain in nomenclature and definition for research and reporting purposes. These operational definitions were selected by consensus of a multidisciplinary writing group to provide consistency for reporting on imaging in clinical trials and observational studies involving cerebral aneurysms. These definitions should help different groups to publish results that are directly comparable.
Deep brain stimulation (DBS) is a new neurosurgical method principally used for the treatment of Parkinson disease (PD). Many new applications of DBS are under development, including the treatment of intractable psychiatric diseases. Brain imaging is used for the selection of patients for DBS, to localize the target nucleus, to detect complications, and to evaluate the final electrode contact position. In patients with implanted DBS systems, there is a risk of electrode heating when MR imaging is performed. This contraindicates MR imaging unless specific precautions are taken. Involvement of neuroradiologists in DBS procedures is essential to optimize presurgical evaluation, targeting, and postoperative anatomic results. The precision of the neuroradiologic correlation with anatomic data and clinical outcomes in DBS promises to yield significant basic science and clinical advances in the future.
]]>Hyperpolarization is the general term for a method of enhancing the spin-polarization difference of populations of nuclei in a magnetic field. No less than 5 distinct techniques (dynamic nuclear polarization [DNP]; parahydrogen-induced polarization–parahydrogen and synthesis allow dramatically enhanced nuclear alignment [PHIP-PASADENA]; xenon/helium polarization transfer; Brute Force; 1H hyperpolarized water) are currently under exhaustive investigation as means of amplifying the intrinsically (a few parts per million) weak signal intensity used in conventional MR neuroimaging and spectroscopy. HD-MR imaging in vivo is a metabolic imaging tool causing much of the interest in HD-MR imaging. The most successful to date has been DNP, in which carbon-13 (13C) pyruvic acid has shown many. PHIP-PASADENA with 13C succinate has shown HD-MR metabolism in vivo in tumor-bearing mice of several types, entering the Krebs–tricarboxylic acid cycle for ultrafast detection with 13C MR imaging, MR spectroscopy, and chemical shift imaging. We will discuss 5 promising preclinical studies: 13C succinate PHIP in brain tumor; 13C ethylpyruvate DNP and 13C acetate; DNP in rodent brain; 13C succinate PHIP versus gadolinium imaging of stroke; and 1H hyperpolarized imaging. Recent developments in clinical 13C neurospectroscopy encourage us to overcome the remaining barriers to clinical HD-MR imaging.
]]>CT perfusion (CTP) mapping has been reported to be useful in the differentiation of the infarct core and ischemic penumbra. However, the value of the CTP source imaging (CTP-SI) during the arterial and venous phases has not been fully investigated. The purpose of this study was to develop a CTP-SI methodology for acute ischemic stroke and compare its efficacy with cerebral blood flow (CBF) and cerebral blood volume (CBV) in predicting infarct core and penumbra.
CT examinations, including non-contrast-enhanced CT, CTP, and CT angiography (CTA), were performed in 42 patients with symptoms of stroke for <9 hours. The Alberta Stroke Program Early CT Score (ASPECTS) was analyzed on the arterial phase CTP-SI and venous phase CTP-SI and then compared with the ASPECTS on CBF and CBV for efficacy assessment.
The ASPECTS on the arterial phase CTP-SI was closely correlated with the ASPECTS on CBF, the Pearson correlation coefficient was 0.88 (P < .001), and the concordance correlation coefficient was 0.7603 (95% confidence interval [CI], 0.6331–0.8476). The ASPECTS on the venous phase CTP-SI revealed a significant correlation with the ASPECTS on CBV, the Pearson correlation coefficient was 0.92 (P < .001), and the concordance correlation coefficient was 0.8880 (95% CI, 0.8148–0.9334). Significant differences were shown between the arterial phase CTP-SI/ venous phase CTP-SI (P < .001) and CBF/CBV (P < .001).
This study provides preliminary evidence that the arterial phase and venous phase CTP-SI mismatch model could possibly be applied to ischemic regions in the acute stage of stroke to determine penumbra and infarct core.
Relative cerebral blood volume (rCBV) accuracy can vary substantially depending on the dynamic susceptibility-weighted contrast-enhanced (DSC) acquisition and postprocessing methods, due to blood-brain barrier disruption and resulting T1-weighted leakage and T2- and/or T2*-weighted imaging (T2/T2*WI) residual effects. We set out to determine optimal DSC conditions that address these errors and maximize rCBV accuracy in differentiating posttreatment radiation effect (PTRE) and tumor.
We recruited patients with previously treated high-grade gliomas undergoing image-guided re-resection of recurrent contrast-enhancing MR imaging lesions. Thirty-six surgical tissue samples were collected from 11 subjects. Preoperative 3T DSC used 6 sequential evenly timed acquisitions, each by using a 0.05-mmol/kg gadodiamide bolus. Preload dosing (PLD) and baseline subtraction (BLS) techniques corrected T1-weighted leakage and T2/T2*WI residual effects, respectively. PLD amount and incubation time increased with each sequential acquisition. Corresponding tissue specimen stereotactic locations were coregistered to DSC to measure localized rCBV under varying PLD amounts, incubation times, and the presence of BLS. rCBV thresholds were determined to maximize test accuracy (average of sensitivity and specificity) in distinguishing tumor (n = 21) and PTRE (n = 15) samples under the varying conditions. Receiver operator characteristic (ROC) areas under the curve (AUCs) were statistically compared.
The protocol that combined PLD (0.1-mmol/kg amount, 6-minute incubation time) and BLS correction methods maximized test AUC (0.99) and accuracy (95.2%) compared with uncorrected rCBV AUC (0.85) and accuracy (81.0%) measured without PLD and BLS (P = .01).
Combining PLD and BLS correction methods for T1-weighted and T2/T2*WI errors, respectively, enables highly accurate differentiation of PTRE and tumor growth.
Diffusion-weighted imaging (DWI) is sensitive to the cerebral manifestations of human prion diseases. The magnitude of diffusion weighting, termed "b factor," has only been evaluated at the standard b = 1000 s/mm2. This is the first rigorous evaluation of b = 2000 s/mm2 in Creutzfeldt-Jakob Disease (CJD).
We compared DWI characteristics of 13 patients with CJD and 15 healthy controls at b = 1000 s/mm2 and b = 2000 s/mm2. Apparent diffusion coefficients (ADC) were computed and analyzed for the whole brain by voxel-wise analysis (by SPM5) as well as in anatomically defined volumes of interest (by FSL FIRST).
Measured ADC was significantly lower (by approximately 5%–15%) at b = 2000 s/mm2 than at b = 1000 s/mm2 and significantly lower in patients than in controls. The differences between patients and controls were greater and more extensive at b = 2000 s/mm2 than at b = 1000 s/mm2 in the expected regions (thalamus, putamen, and caudate nucleus).
Because higher b factors change the absolute value of observed ADC, as well as lesion detection, care should be taken when combining studies using different b factors. While the clinical application of high b factors is currently limited by a low signal intensity–to-noise ratio, it may offer more information in questionable cases, and our results confirm and extend the central role of diffusion imaging in human prion diseases.
Susceptibility-weighted (SW) MR imaging has enabled noninvasive visualization of the cerebral veins and has shed light on the nature of venous architecture. For successful surgery of the third ventricle, understanding of the anatomy of the subependymal veins of the lateral ventricle and their relationships to the foramen of Monro is required preoperatively. The purpose of this study was to evaluate the anatomic variations of the subependymal veins around the third ventricle by use of phase-sensitive imaging (PSI) on the basis of principles similar to those of SW MR imaging.
Included in this study were 642 sides in 321 patients. The courses of the anterior septal vein (ASV), thalamostriate vein, and internal cerebral vein (ICV) were evaluated. We classified these into 4 types (IA, IB, IIA, IIB) on the basis of standard classic angiographic criteria. The classification is based on their relationship with the ASV-ICV junction and the presence of a venous angle or a false venous angle, according to the method in a previous study. Other venous variations were classified as type III.
A venous angle was formed in 519 (80.9%), whereas a false venous angle was formed in 123 (19.1%). The ASV-ICV junction was located at the venous angle (type IA) in 407 (63.4%) of 642 sides. In 235 sides (36.6%), the ASV-ICV junction was located posteriorly beyond the foramen of Monro (types IB, IIA, IIB, and III).
PSI is useful for understanding normal variations of the subependymal veins in the region of the third ventricle.
There is evidence that increased tumor cellular density within diagnostic specimens of primary central nervous system lymphoma (PCNSL) may have significant prognostic implications. Because cellular density may influence measurements of apparent diffusion coefficient (ADC) by using diffusion-weighted MR imaging (DWI), we hypothesized that ADC measured from contrast-enhancing regions might correlate with clinical outcome in patients with PCNSL.
PCNSL tumors from 18 immunocompetent patients, treated uniformly with methotrexate-based chemotherapy, were studied with pretherapeutic DWI. Enhancing lesions were diagnosed by pathologic analysis as high-grade B-cell lymphomas. Regions of interest were placed around all enhancing lesions allowing calculation of mean, 25th percentile (ADC25%), and minimum ADC values. Histopathologic tumor cellularity was quantitatively measured in all patients. High and low ADC groups were stratified by the median ADC value of the cohort. The Welch t test assessed differences between groups. The Pearson correlation examined relationships between ADC measurements and tumor cellular density. Single and multivariable survival analysis was performed.
We detected significant intra- and intertumor heterogeneity in ADC measurements. An inverse correlation between cellular density and ADC measurements was observed (P < .05). ADC25% measurements less than the median value of 692 (low ADC group) were associated with significantly shorter progression-free and overall survival. Patients with improved clinical outcome were noted to exhibit a significant decrease in ADC measurements following high-dose methotrexate chemotherapy.
Our study provides evidence that ADC measurements within contrast-enhancing regions of PCNSL tumors may provide noninvasive insight into clinical outcome.
Acute hydrocephalus after aneurysmal subarachnoid hemorrhage (SAH) may decrease cerebral perfusion by increasing intracranial pressure. We studied cerebral perfusion in patients with and without acute hydrocephalus after SAH.
We performed noncontrast CT scans, CT perfusion (CTP), and CT angiography on admission in all patients with aneurysmal SAH. Patients were dichotomized at a relative bicaudate index of 1 for the presence or absence of hydrocephalus. Cerebral perfusion was measured in the cortex, basal ganglia, and periventricular white matter. Mean CTP parameters were compared between patients with and without acute hydrocephalus (ie, within 3 days after SAH).
We included 138 consecutive patients with successful CTP measurements, of whom 49 (36%) had acute hydrocephalus. Mean cerebral blood flow (CBF) was lower in patients with hydrocephalus than in those without in the basal ganglia (difference of means, 6.8; 95% CI, 1.6–11.0 mL/100 g/min) and periventricular white matter (difference of means, 3.8; 95% CI, 0.9–6.8 mL/100 g/min) but not in the cortex (difference of means, 1.8; 95% CI, –2.8 to 6.4 mL/100 g/min). In all regions studied, mean transit time (MTT) and time-to-peak (TTP) were statistically significantly longer in patients with hydrocephalus, but cerebral blood volume (CBV) values were similar.
Acute hydrocephalus after SAH reduces CBF in the deep gray matter and periventricular white matter and delays MTT and TTP in all investigated brain areas. The negative effect of acute hydrocephalus on cerebral perfusion in patients with SAH seems more pronounced in the vicinity of the ventricles than in remote sites.
Radiologic identification of the location of the CSF leakage is important for proper surgical planning and increases the chance of dural repair. This article describes our experience in analyzing clinically suspected cranial CSF fistulas by using MR imaging combined with the intrathecal administration of a gadolinium-based contrast agent.
A total of 85 consecutive patients with suspected CSF fistulas who presented with persistent or intermittent rhinorrhea or otorrhea lasting for more than 1 month between 2003 and 2007 were included in this study.
We observed objective CSF leakage in 64 of 85 patients (75%). The CSF leak was located in the ethmoidal region in 37 patients (58%), in the superior wall of the sphenoid sinus in 8 patients (13%), in the posterior wall of the frontal sinus in 10 patients (15%), in the superior wall of the mastoid air cells in 6 patients (9%), and from the skull base into the infratemporal fossa in 1 patient (2%). Two patients (3%) showed leakage into >1 paranasal sinus.
MR cisternography after the intrathecal administration of gadopentate dimeglumine represents an effective and minimally invasive method for evaluating suspected CSF fistulas along the skull base. It provides multiplanar capabilities without risk of radiation exposure and is an excellent approach to depict the anatomy of CSF spaces and CSF fistulas.
Neuromyelitis optica (NMO) is an idiopathic mostly relapsing inflammatory disease with attacks on the optic nerves and spinal cord. Whether NMO is a separate disease or a subtype of classic multiple sclerosis (MS) is unclear. Clinically, CSF and MR imaging parameters and histopathologic data suggest that the normal-appearing white matter (NAWM) may be affected in MS but not in patients with NMO. Therefore, we hypothesized that the NAWM in NMO is normal.
We studied prospectively 8 patients with clinically definitive NMO or remitting longitudinal extensive transverse myelitis (LETM) and 8 healthy controls. Ratios of N-acetylaspartate to creatine (Cr) and choline to Cr and the absolute concentrations of the metabolites were measured by chemical shift imaging with a 1H-MR spectroscopy operating at 3T. All patients with clinically definitive NMO and LETM were found to be positive for NMO–immunoglobin G with a commercially available test.
The metabolic pattern of the NAWM of patients with NMO showed no difference compared with age- and sex-matched healthy controls.
Diffuse white matter damage is absent in NMO.
Four-dimensional contrast-enhanced MR angiography (4D-CE-MRA) at 3T may replace digital subtraction angiography (DSA) for certain diagnostic purposes in patients with intracranial dural arteriovenous fistula (DAVF). The aim of this study was to test the hypothesis that 4D-CE-MRA at 3T enables the same characterization of intracranial DAVFs as DSA.
The study population consisted of 18 consecutive patients with intracranial DAVFs (11 women, 7 men; age range, 35–82 years; mean age, 64.8 years). They underwent 4D-CE-MRA at 3T and DSA. The 4D-CE-MRA series combined randomly segmented central k-space ordering, keyhole imaging, sensitivity encoding, and half-Fourier imaging. We obtained 30 dynamic scans every 1.9 seconds with a spatial resolution of 1 x 1 x 1.5 mm. Two independent readers reviewed the 4D-CE-MRA images for main arterial feeders, fistula site, and venous drainage. Interobserver and intermodality agreement was assessed by statistics.
At DSA, 8 fistulas were located at the transverse sigmoid sinus; 8, at the cavernous sinus; and 2, at the sinus adjacent to the foramen magnum. Interobserver agreement was fair for the main arterial feeders ( = 0.59), excellent for the fistula site ( = 0.91), and good for venous drainage ( = 0.86). Intermodality agreement was moderate for the main arterial feeders ( = 0.68) and excellent for the fistula site ( = 1.0) and venous drainage ( = 1.0).
The agreement between 4D-CE-MRA and DSA findings was good to excellent with respect to the fistula site and venous drainage.
In this report, we present a case of a patient with CT angiographic artifacts related to left-sided venous injection resulting in a striking pattern of enhancement simulating vascular abnormalities, which prompted additional diagnostic imaging. To our knowledge, no similar case has been reported in the published literature to date.
]]>Lipoid proteinosis is a rare genodermatosis characterized by multisystem involvement due to intracellular deposition of an amorphous hyaline material. Lipoid proteinosis is caused by mutations in the ECM1 gene. In many patients, skin and mucosa abnormalities are the first manifestation. When the CNS is affected, a wide variety of neurologic abnormalities may be present. The hallmark findings are calcifications, mostly occurring in the amygdalae, hippocampus, parahippocampal gyrus, or even the striatum. Present in half of the patients, moniliform blepharosis is considered a pathognomonic finding. In the other half of patients imaging could assist in the diagnosis. The authors present a series of 3 cases of lipoid proteinosis with brief clinical data and imaging findings.
]]>Sixty-four-section CT scanners have recently been introduced for vascular imaging. Before such scanners reach widespread use, scanning protocol should be optimized and image quality assessed. The goals of this study were to systematically measure image quality and determine the prevalence of various types of artifacts produced by a 64-section scanner.
We retrospectively reviewed CT angiography (CTA) scans obtained on a 64-section CT scanner in 100 consecutive patients presenting to the emergency department during a 2-month period with a suspected acute cerebrovascular event. We evaluated scan quality by using 2 different methods: First, we quantitatively assessed arterial opacification by measuring attenuation values in 9 arterial segments from the aortic arch to the distal cervical internal carotid artery, by using a threshold of 150 HU as an indicator of good opacification. Second, we assessed image contrast between arteries and veins by measuring attenuation within venous segments and recording the number of artery-vein-segment pairs in which the attenuation difference was ≤50 HU. In addition, we recorded the prevalence of the following artifacts: metallic hardware streak, contrast material streak from slow-flowing contrast material in adjacent large veins, streak artifacts from shoulders, contrast material reflux into veins of the neck, motion artifacts, and artifacts causing misrepresentation of flow dynamics simulating arterial dissection or occlusion. These results were compared with those of a historical control group of 113 patients from our institution who were imaged with the same technical parameters on a 16-section CT scanner.
The quantitative assessment of arterial opacification showed that 854 of 885 analyzed arterial segments (96.5%) had good opacification (ie, attenuation values >150 HU). Image contrast between artery and vein segments was also good, with 714 of 763 analyzable segment pairs (85.6%) having >50 HU difference. Artifacts obscuring arterial evaluation included streak from contrast material in the subclavian/brachiocephalic vein (32% of patients), attenuation of the x-ray beam between the shoulders (28%), beam-hardening from metallic hardware (26%), and contrast material reflux into neck veins (16%). The most clinically relevant artifacts were flow artifacts, mimicking dissection or vascular occlusion; they were seen in 14% of patients and likely are related to the rapid data acquisition for CTA on 64-section scanners (compared with the circulation of contrast material in the cervical arteries). None of the patients in our historical control group who underwent 16-section CT had flow artifacts on their CTA studies; the incidence of the other types of artifacts in this group was similar to that in patients imaged with 64-section CT.
The 64-section CTA imaging protocol for carotid arteries yields high-quality studies in >95% of cases.
CSF loss with consecutive intracranial hypotension has been discussed as a possible pathogenetic mechanism in poor clinical outcome after uneventful neurosurgery and appears to be correlated to specific imaging findings. The purpose of this study was to describe the clinical and imaging findings of symptomatic intracranial hypotension likely induced by wound suction drainage.
This is a review of previously published cases of patients in whom this condition developed after uneventful intracranial surgery. We performed an analysis of 3 more cases, of which 2 occurred after spinal surgery with accidental dural opening.
Sixteen patients who remained unconscious or did not become fully responsive after surgery showed symmetric bilateral thalamic/basal ganglia signal intensity changes on CT and MR imaging studies. Of these 16 patients, 4 died and 2 also had brain stem signal intensity changes. All patients had rapid and distinct intraoperative and postoperative CSF loss documented on CT and/or MR imaging studies by a transient increase of the sag ratio, defined as maximal anteroposterior midbrain diameter by maximal bipeduncular diameter.
The clinical course and typical MR imaging findings characterize the disease entity postsurgical intracranial hypotension. These findings also underline the potential danger of wound suction drainage in the case of possible CSF loss.
Fetal ventriculomegaly (VM) is important because of its high prevalence and high risk of association with other brain abnormalities. The purpose of this article was to investigate the hypotheses that including in utero MR imaging (iuMR) in the diagnostic pathway for fetuses with isolated VM on antenatal imaging will show other brain abnormalities in a high proportion of cases and that these will have a significant effect on clinical management.
One hundred forty-seven pregnant women were recruited prospectively from 8 fetomaternal centers in Britain. All of the fetuses had VM diagnosed on sonography but no other abnormality. iuMR was performed, and the results of the examinations were compared with those of sonography. Two fetomaternal experts made independent assessments of the effects of any new diagnoses on clinical management.
Categoric assessments of ventricular size were the same in approximately 90% of fetuses. Other abnormalities were shown in 17% of fetuses. The most frequent additional brain abnormality shown on iuMR was agenesis of the corpus callosum. Severe VM was associated with an approximately 10-fold increase in the risk of another brain abnormality being present when compared with fetuses with mild VM. The most profound effects on clinical management, however, were found in cases of mild VM.
This work supports our hypotheses by showing a high detection rate of other brain pathology when iuMR was used to supplement antenatal sonography (17%). In a high proportion of cases, the detection of the extra pathology would have led to significant changes in clinical management.
The safety and efficacy of Onyx for the embolization of central nervous system (CNS) arteriovenous (AV) lesions have been widely reported in adults. However, data describing the use of this agent in children are limited. This study presents our experience with Onyx in the treatment of CNS AV lesions in pediatric patients.
We retrospectively analyzed clinical and imaging records of 15 pediatric patients who underwent 36 transarterial embolizations by using Onyx for CNS AV lesions, from March 2007 through April 2009 at our institution. Underlying pathologies included brain AV malformations (AVMs) (n = 7), vein of Galen malformations (n = 4), dural AV fistulas (n = 2), and spinal AVMs (n = 2). For 7 procedures in very high-flow lesions, detachable coils were deployed before Onyx embolization, whereas in 29 procedures, Onyx was the sole embolic agent. The efficacy of embolization was judged by the residuum of AV shunting within the target region.
Embolization was complete in 2 patients, nearly complete in 9 patients, and partial (and ongoing) in 4 patients. Following staged embolization, 7 patients underwent surgical resection without significant blood loss and with good functional outcome in all cases. Clinically silent non-target embolization was encountered in 2 of 36 procedures. After 3 of the 36 embolizations, patients developed transient neurologic symptoms, all of which resolved to baseline within 24 hours. There were no non-neurologic adverse events. There was no imaging evidence of infarct or hemorrhage.
Onyx embolization of pediatric CNS AV lesions can be an efficacious treatment technique, with extremely low associated morbidity.
Region-of-interest (ROI) and tract-based diffusion tensor imaging (DTI) analyses have detected increased apparent diffusion coefficients (ADCs) and decreased fractional anisotropy (FA) in callosal and projection systems of adult patients with multiple sclerosis (MS). We explored whether similar changes occur in pediatric patients with MS, assessing 3 major white matter pathways (interhemispheric, projection, and intrahemispheric) in both visibly involved and normal-appearing white matter (NAWM).
DTI datasets from 10 patients with established pediatric MS and 10 age- sex-, and imaging technique–matched controls were analyzed. Tracts were reconstructed by using a fiber assignment by continuous tracking algorithm with a diffusion-weighted imaging mask and a 35° angular threshold. Tracts were selected by using standard ROI placements on color FA maps cross-referenced to b = 0 T2-weighted images for studying white matter pathways. Ten identical ROIs were placed in NAWM on b = 0 T2-weighted images to ensure that both ROIs and resulting tracts passed through NAWM.
In pediatric MS, all tracts had higher mean ADC values (P = .002 to P < .04) and lower mean FA (P = .009 to P < .02) than those in healthy controls. Even when the tracts were confined to NAWM, the mean ADC was higher (P < .004 to P < .05) and the mean FA was lower (P = .002 to P < .02). T2 lesion burden correlated with tract-based mean ADC. ROI mean ADC increased, and both tract and ROI mean FA decreased with increasing T2 lesion burden, however with a statistically nonsignificant correlation.
Increased mean ADC and decreased mean FA occur in all 3 major white matter pathways, both in visibly involved white matter and NAWM in pediatric MS.
Trichothiodystrophy (TTD) is a rare group of autosomal recessive disorders of DNA repair unified by the presence of sulfur-deficient brittle hair. We report a 3-year-old boy with classic clinical features of TTD, including ichthyosis, alopecia, developmental delay, and tiger-tail banding of the hair shaft on polarizing microscopy. Brain MR imaging showed both diffuse dysmyelination and osteosclerosis, findings that, in combination, may be specific for TTD.
]]>Individuals with autism spectrum disorders often exhibit atypical language patterns, including delay of speech onset, literal speech interpretation, and poor recognition of social and emotional cues in speech. We acquired functional MR images during an auditory language task to evaluate systematic differences in language-network activation between control and high-functioning autistic populations.
Forty-one right-handed male subjects (26 high-functioning autistic subjects, 15 controls) were studied by using an auditory phrase-recognition task, and areas of differential activation between groups were identified. Hand preference, verbal intelligence quotient (IQ), age, and language-function testing were included as covariables in the analysis.
Control and autistic subjects showed similar language-activation networks, with 2 notable differences. Control subjects showed significantly increased activation in the left posterior insula compared with autistic subjects (P < .05, false discovery rate), and autistic subjects showed increased bilaterality of receptive language compared with control subjects. Higher receptive-language scores on standardized testing were associated with greater activation of the posterior aspect of the left Wernicke area. A higher verbal IQ was associated with greater activation of the bilateral Broca area and involvement of the prefrontal cortex and lateral premotor cortex.
Control subjects showed greater activation of the posterior insula during receptive language, which may correlate with impaired emotive processing of language in autism. Subjects with autism showed greater bilateral activation of receptive-language areas, which was out of proportion to the differences in hand preference in autism and control populations.
A precise analysis of the immediate postoperative anatomic results in a large series of unruptured intracranial aneurysms treated by endovascular approach has not previously been presented. This study aimed to assess the efficacy of endovascular treatment of unruptured intracranial aneurysms in light of immediate postoperative anatomic results in a prospective, multicenter study (the Analysis of Treatment by Endovascular Approach of Nonruptured Aneurysms study; ATENA).
Postoperative anatomic results from digital subtraction angiography (DSA) were evaluated with the Montreal scale by the treating physician and by 2 anonymous, independent, experienced neuroradiologists.
The analysis included 622 patients (449 women, 173 men; age range, 22–83 years; mean age, 51.2 ± 11.3 years) harboring 694 aneurysms. Evaluation of the postoperative anatomic results by the 2 independent reviewers indicated total occlusions in 437 aneurysms (63.0%), neck remnants in 156 aneurysms (22.5%), and aneurysm remnants in 101 aneurysms (14.6%). Several factors favorably affected the quality of the aneurysm occlusion with treatment, including patient age (< 65 years old; P < .0001), aneurysm diameter (≤ 6 mm; P = .0049), aneurysm dome-to-neck ratio (> 1.5; P = .0388), and endovascular technique (coiling or remodelling compared with stent placement; P = .0001).
The endovascular treatment of unruptured aneurysms provided satisfactory postoperative occlusion rates, with a high percentage of complete occlusion or neck remnants (85.4%). Postoperative anatomic results were significantly affected by aneurysm size and neck size, but not aneurysm location.
Because of the concern for occlusion of the incorporated branch artery, an aneurysm with a branch incorporated into the sac has been regarded as a contraindication for coiling. The aim of this study is to evaluate the feasibility, techniques, and clinical and angiographic outcomes of coiling for aneurysms with a branch incorporated into the sac.
The medical records and radiologic studies of 69 patients with 79 aneurysms having a branch incorporated into the sac (26 ruptured, 53 unruptured) were retrospectively reviewed and evaluated.
Coiling was accomplished in 78 aneurysms in 68 patients but was suspended in 1 due to incorporated branch occlusion. The aneurysms were treated by using the following techniques: single-catheter (n = 37), multicatheter (n = 22), balloon-remodeling (n = 7), stent-assisted coiling (n = 6), and combined (n = 7). Postembolization angiography revealed the following: near-complete occlusion in 71 (89.8%), remnant neck in 4 (5.1%), and incomplete occlusion in 4 (5.1%) aneurysms. Procedure-related permanent morbidity and mortality rates were 5.8% (4/69) and 0%, respectively. All patients with unruptured aneurysms had a modified Rankin Scale (mRS) score of 0, except for 1 patient who had an mRS score of 3. Of the 26 patients with ruptured aneurysms, 18 had favorable outcome (mRS 0–2) but 8 had poor outcome (mRS 3–6). Follow-up angiography was available at least once at 6–50 months (mean, 15 months) in 55 aneurysms (69.6%), of which 45 showed stable or improved occlusion; 4, minor recurrences; and 6, major recurrences. All 6 major recurrent aneurysms were retreated without complication by using a single-catheter (n = 1), multicatheter (n = 2), or balloon-assisted technique (n = 3).
With appropriate techniques, most aneurysms with a branch incorporated into the sac could be safely treated by coiling, with acceptable outcomes.
Particle embolization is widely used in the treatment of meningiomas. We assessed the frequency and outcome of complications of embolization of meningiomas and tried to identify risk factors.
Between 1994 and 2009, a total of 198 patients with 201 meningiomas underwent embolization. Indication for embolization was preoperative in 165 meningiomas and adjunctive to radiosurgery in 8. In the remaining 28 meningiomas, embolization was initially offered as a sole therapy. There were 128 women and 70 men with a mean age of 54.4 years (median age, 54 years; range, 15–90 years). Complications were defined as any neurologic deficit or death that occurred during or after embolization. Logistic regression was used to identify the following possible risk factors: age above median, female sex, tumor size above median, meningioma location in 5 categories, use of small particle size (45–150 µm), the presence of major peritumoral edema, and arterial supply in 3 categories.
Complications occurred in 11 patients (5.6%; 95% confidence interval [CI], 3.0%–9.8%). Ten complications were hemorrhagic, and 1 was ischemic. Six of 10 patients with hemorrhagic complications underwent emergency surgery with removal of the hematoma and meningioma. Complications of embolization resulted in death in 2 and dependency in 5 patients (7/198, 3.5%; 95% CI, 1.6%–2.0%). The use of small particles (45–150 µm) was the only risk factor for complications (odds ratio [OR], 10.21; CI, 1.3–80.7; P = .028).
In this series, particle embolization of meningiomas had a complication rate of 5.6%. We believe that the use of small polyvinyl alcohol (PVA) particles (45–150 µm) should be discouraged.
Intracranial fusiform aneurysms, which incorporate the branch vessel and require salvaging of the parent vessel, are difficult to manage. The goal of this study was to evaluate the efficacy of reconstructive endovascular treatment of intracranial fusiform aneurysms by using a 1-stage procedure with a stent and balloon.
During a 3-year period, 20 patients with 20 intracranial fusiform aneurysms were treated by using a 1-stage procedure involving a balloon and stent. Subarachnoid hemorrhage was present in 15 patients. Five aneurysms were located in the anterior circulation and 15, in the posterior circulation. Clinical outcomes and periprocedural complications were evaluated in all patients. The extent of coil packing was evaluated by control angiography after embolization and classified as either complete occlusion or partial occlusion. Angiography was performed 6, 12, and 24 months after embolization to evaluate stent patency and coil packing.
The 1-stage procedure by using a combination of balloon and stent was technically successful in all patients. There were no complications related to the procedure, complete occlusion was obtained in 16 patients, and partial occlusion, in 4 patients. All patients recovered well except for 2 who died due to causes unrelated to the procedure. Clinical follow-up was performed in all surviving patients at a mean of 12.3 months (range, 7–24 months), and angiography showed that the patent parent arteries were free of aneurysm recanalization or in-stent stenosis.
This 1-stage procedure may provide a feasible and safe treatment strategy for the management of intracranial fusiform aneurysms that are not amenable to deconstructive embolization.
Intravenous (IV) thrombolysis often fails to achieve recanalization of occluded cerebral arteries, especially in patients with proximal large arterial occlusions. The goal of this study was to assess the feasibility, safety, and efficacy of low-dose intra-arterial (IA) urokinase and aggressive mechanical clot disruption (AMCD) after failure of IV thrombolysis for acute ischemic stroke.
We prospectively enrolled 12 patients with acute ischemic stroke who initially received IV recombinant tissue plasminogen activator (rtPA) and were subsequently treated with combined low-dose IA urokinase and AMCD. Time to treatment, urokinase dose, duration of the procedure, recanalization rates, and symptomatic hemorrhage were analyzed. Clinical outcome measures were assessed on admission and at discharge (National Institutes of Health Stroke Scale [NIHSS]), and at 3 months after treatment (modified Rankin Scale [mRS]).
Median NIHSS score on admission was 17. Median time from symptom onset to IV rtPA was 120 minutes, and median time from symptom onset to IA therapy was 230 minutes. The median duration of IA therapy was 55 minutes. Median dose of urokinase was 300,000 U. Recanalization (thrombolysis in cerebral ischemia grade II or III) was achieved in all patients. No procedure-related complications were observed. There was no symptomatic hemorrhage. At discharge, median NIHSS score was 3. The 3-month outcome was excellent (mRS, 0–1) in 8 patients, good (mRS, 2) in 1 patient, and poor (mRS, 3–5) in 3 patients. There was no hospital or 3-month mortality.
In this study, combination therapy with low-dose IA urokinase and AMCD is safe and effective after failed IV thrombolysis in patients with acute ischemic stroke. A high rate of recanalization, low rate of symptomatic hemorrhage, and excellent functional outcome can be achieved.
The pathophysiology of saccular aneurysms is complex and multifactorial. The aim of the present study was to understand the mechanism of apoptosis in an elastase-induced aneurysm model in rabbits.
Elastase-induced saccular aneurysms were created at the origin of the right common carotid artery in 20 rabbits. Aneurysm samples were harvested at 2 and 12 weeks after creation. Expression of apoptosis-associated proteins, including caspases and bcl-2 proteins, were assessed by Western blot analysis (n = 5 at both time points). Terminal deoxynucleotidyltransferase–mediated dUTP nick end-labeling (TUNEL) staining, which indicates the presence of apoptosis, was performed in tissue sections (n = 5 at both time points). The unoperated contralateral common carotid artery was used as a control.
Expression of active caspase-3, the final executioner of apoptosis, and caspase-9, the mediator of the intrinsic mitochondrial pathway, was observed in aneurysms at 2 weeks, whereas the expression of activated caspase-8, the mediator of the extrinsic death receptor pathway, was absent at both time points. Expression of antiapoptotic proteins, Bcl-2 and phospho-Bad, was down-regulated in aneurysms compared with controls at 2 weeks. None of these proteins were differentially expressed at 12 weeks. These results were confirmed by the presence of TUNEL-positive cells in some aneurysms at the early time point.
In this study of elastase-induced aneurysms in a rabbit model, activation of apoptosis is mediated predominantly by the Bcl-2-mediated intrinsic pathway through the activation of caspase-9.
In vitro and nonhuman in vivo studies demonstrating impaired fibrinolysis of thrombus by thrombolytic agents in the presence of iodinated contrast media (ICM) have prompted concern regarding the clinical use of ICM. A systematic review and meta-analysis were performed to investigate the proportion of patients with acute stroke experiencing recanalization after thrombolytic therapy in whom ICM were administered compared with those in whom they were not.
Embase and Medline searches identified studies reporting recanalization rates in acute ischemic anterior circulation stroke. Pooled proportions of patients who recanalized were calculated with a random-effects model, and studies involving contrast (CS) were compared with those without (NCS).
Six studies were found in which ICM were administered, and 12 studies, in which they were not. Studies were statistically heterogeneous. Combined pooled proportions and 95% confidence intervals (CI) for recanalization in unselected CS and NCS were 53% (36%–70%) and 61% (52%–71%), respectively. In a subgroup analysis in which only middle cerebral artery occlusions were considered, the pooled proportions in CS (n = 3 studies) and NCS (n = 9 studies) were 66% (95% CI, 49%–82%; I2, 0%) and 63% (CI, 52%–74%; I2, 82.5%).
Recanalization rates were not significantly different in patients who received iodinated contrast agents in clinical studies. A randomized trial to test whether ICM affect recanalization would require a prohibitively large number of subjects.
Our aim was to describe the immediate or early complications and technical failures occurring during balloon kyphoplasty (BKP) procedures and attributable to balloon inflation.
We performed a retrospective review of all consecutive kyphoplasty procedures performed in our institution from May 2005 to October 2006. Fifty-one patients were treated by BKP at 75 spinal levels, and 137 vertebroplasties were performed as well.
Several recurrent complications or procedural failures were observed during BKP: cortical or endplate fracture by balloon expansion (4 vertebrae), partial vertebral re-collapse after deflation (4 vertebrae), balloon rupture during inflation (5 vertebrae), and transient hyperalgia after the procedure (11 patients, 27.5%).
Several symptomatic or asymptomatic complications and technical failures can occur during BKP. Some modifications of the usual kyphoplasty technique may decrease the frequency of these complications.
Brain proton MR spectroscopy (1H-MR spectroscopy) is a useful technique for evaluating neuronal/axonal damage and demyelization in multiple sclerosis (MS). Because MS disability is frequently related to spinal cord lesions, potential markers for MS stage differentiation and severity would require in vivo quantification of spinal integrity. However, few spectroscopy studies have investigated cervical disease due to technical difficulties. The present study used 3T 1H-MR spectroscopy to measure the main metabolites in cervical spinal cord plaques of a group in patients with relapsing-remitting MS (RRMS) and compared them with metabolite measurements in healthy volunteers.
A 1H-MR point-resolved spectroscopy sequence volume of interest was prescribed along the main axis of the cord between C2 and C3 levels on a plaque in a group of 15 patients with RRMS for a total acquisition time of approximately 14 minutes. MR spectroscopy data were analyzed by the user-independent fitting routine LCModel, and relative metabolite concentrations were expressed by the absolute concentration ratios. A Student t test was used to evaluate the difference compared with the healthy metabolite content previously published.
We found a significant decrease of total N-acetylaspartate/choline and an increase in choline/creatine and myo-inositol/creatine content on MS plaques in comparison with healthy cervical spine tissue.
In vivo 1H-MR spectroscopy, if confirmed by other similar studies, should be as reliable for clinical studies as it is in brain imaging. Moreover, 1H-MR spectroscopy allows examination of spinal cord integrity at a biochemical level and may be sensitive to subtle changes occurring during the course of MS disease.
How CSF flow varies with the anatomy of the subarachnoid space has not been sufficiently well studied. The goal of this study was to develop an idealized 3D computational model of the subarachnoid space and then to use this model to study the detailed spatiotemporal effects of anatomic variations on CSF pressures and velocities.
We created a geometric model with a computer-assisted design program. The model contained a central structure for the brain and spinal cord axis and a second surrounding structure for the peripheral borders of the subarachnoid space. Model dimensions were adjusted to capture the main characteristics of the normal human posterior fossa and cervical spinal anatomy. CSF flow was modeled as water with a sinusoidal flow pattern in time. Velocities and pressures during craniocaudal and caudocranial flow were calculated with computational fluid dynamics (CFD) software. Simulated flow was compared with published phase-contrast MR imaging measurements of CSF flow in healthy human subjects.
The model contained geometric characteristics of the posterior fossa and spinal canal. Flow velocities varied with the time in the cycle and location in space. Flow velocities had spatial variations that resembled those in healthy human subjects. Reynolds numbers were moderate, showing a laminar flow regime. Pressure varied uniformly along the long axis of the model during craniocaudal and caudocranial flow.
In an idealized geometric approximation of the human subarachnoid space, CSF velocities and pressures can be studied in spatiotemporal detail with mathematic models.
A novel transosseous approach for percutaneous access of the lumbar subarachnoid space is described in a patient with advanced ankylosing spondylitis (AS) and instrumented spinal fusion who presented for myelography. Use of a coaxial threaded bone biopsy system to provide transosseous access to the thecal sac, imaging findings, and outcome are discussed. This technique provided access to an otherwise inaccessible subarachnoid space and is an alternative approach in the setting of advanced AS or posterior spinal fusion.
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