Showing papers in "American Journal of Neuroradiology in 2009"

CT angiography clot burden score and collateral score: correlation with clinical and radiologic outcomes in acute middle cerebral artery infarct.

Abstract: BACKGROUND AND PURPOSE: Clot extent, location, and collateral integrity are important determinants of outcome in acute stroke. We hypothesized that a novel clot burden score (CBS) and collateral score (CS) are important determinants of clinical and radiologic outcomes and serve as useful additional stroke outcome predictors. MATERIALS AND METHODS: One hundred twenty-one patients with anterior circulation infarct presenting within 3 hours of stroke onset were reviewed. The Spearman correlation was performed to assess the correlation between CBS and CS and clinical and radiologic outcome measures. Patients were dichotomized by using a 90-day modified Rankin scale (mRS) score. Uni- and multivariate logistic regression models were used to assess variables predicting favorable clinical and radiologic outcomes. Receiver operating characteristic and intraclass correlation coefficient (ICC) analyses were performed. Diagnostic performance of a CBS threshold of >6 was assessed. RESULTS: There were 85 patients (mean age, 70 ± 14.5 years). Patients with higher CBS and CS demonstrated smaller pretreatment perfusion defects and final infarct volume and better clinical outcome (all, P 6 predicted good clinical outcome with an area under the curve of 0.75 (95% confidence interval [CI], 0.65–0.84; P = .0001), sensitivity of 73.0 (95% CI, 55.9–86.2), and specificity of 64.6 (95% CI, 49.5–77.8). The recanalization rate with intravenous recombinant tissue plasminogen activator was higher in patients with CBS >6 (P = .04; odds ratio, 3.2; 95% CI, 1.1–9.4). The ICC was 0.97 (95% CI, 0.95–0.98) and 0.87 (95% CI, 0.80–0.91) for CBS and CS, respectively. CONCLUSIONS: CBS and CS are useful additional markers predicting clinical and radiologic outcomes.

Spinal Dural Arteriovenous Fistulas

Abstract: SUMMARY: Spinal dural arteriovenous (AV) fistulas are the most commonly encountered vascular malformation of the spinal cord and a treatable cause for progressive para- or tetraplegia. They most commonly affect elderly men and are classically found in the thoracolumbar region. The AV shunt is located inside the dura mater close to the spinal nerve root where the arterial blood from a radiculomeningeal artery enters a radicular vein. The increase in spinal venous pressure leads to decreased drainage of normal spinal veins, venous congestion, and the clinical findings of progressive myelopathy. On MR imaging, the combination of cord edema, perimedullary dilated vessels, and cord enhancement is characteristic. Therapy has to be aimed at occluding the shunting zone, either by superselective embolization with a liquid embolic agent or by a neurosurgical approach. Following occlusion of the fistula, the progression of the disease can be stopped and improvement of symptoms is typically observed.

Relative Cerebral Blood Volume Values to Differentiate High-Grade Glioma Recurrence from Posttreatment Radiation Effect: Direct Correlation between Image-Guided Tissue Histopathology and Localized Dynamic Susceptibility-Weighted Contrast-Enhanced Perfusion MR Imaging Measurements

Abstract: BACKGROUND AND PURPOSE: Differentiating tumor growth from posttreatment radiation effect (PTRE) remains a common problem in neuro-oncology practice. To our knowledge, useful threshold relative cerebral blood volume (rCBV) values that accurately distinguish the 2 entities do not exist. Our prospective study uses image-guided neuronavigation during surgical resection of MR imaging lesions to correlate directly specimen histopathology with localized dynamic susceptibility-weighted contrast-enhanced perfusion MR imaging (DSC) measurements and to establish accurate rCBV threshold values, which differentiate PTRE from tumor recurrence. MATERIALS AND METHODS: Preoperative 3T gradient-echo DSC and contrast-enhanced stereotactic T1-weighted images were obtained in patients with high-grade glioma (HGG) previously treated with multimodality therapy. Intraoperative neuronavigation documented the stereotactic location of multiple tissue specimens taken randomly from the periphery of enhancing MR imaging lesions. Coregistration of DSC and stereotactic images enabled calculation of localized rCBV within the previously recorded specimen locations. All tissue specimens were histopathologically categorized as tumor or PTRE and were correlated with corresponding rCBV values. All rCBV values were T1-weighted leakage-corrected with preload contrast-bolus administration and T2/T2*-weighted leakage-corrected with baseline subtraction integration. RESULTS: Forty tissue specimens were collected from 13 subjects. The PTRE group (n = 16) rCBV values ranged from 0.21 to 0.71, tumor (n = 24) values ranged from 0.55 to 4.64, and 8.3% of tumor rCBV values fell within the PTRE group range. A threshold value of 0.71 optimized differentiation of the histopathologic groups with a sensitivity of 91.7% and a specificity of 100%. CONCLUSIONS: rCBV measurements obtained by using DSC and the protocol we have described can differentiate HGG recurrence from PTRE with a high degree of accuracy.

Conebeam CT of the head and neck, part 2: clinical applications.

Abstract: SUMMARY: Conebeam x-ray CT (CBCT) is being increasingly used for point-of-service head and neck and dentomaxillofacial imaging This technique provides relatively high isotropic spatial resolution of osseous structures with a reduced radiation dose compared with conventional CT scans In this second installment in a 2-part review, the clinical applications in the dentomaxillofacial and head and neck regions will be explored, with particular emphasis on diagnostic imaging of the sinuses, temporal bone, and craniofacial structures Several controversies surrounding the emergence of CBCT technology will also be addressed

Conebeam CT of the head and neck, part 1: physical principles.

Abstract: Conebeam x-ray CT (CBCT) is a developing imaging technique designed to provide relatively low-dose high-spatial-resolution visualization of high-contrast structures in the head and neck and other anatomic areas. This first installment in a 2-part review will address the physical principles underlying CBCT imaging as it is used in dedicated head and neck scanners. Concepts related to CBCT acquisition geometry, flat panel detection, and image quality will be explored in detail. Particular emphasis will be placed on technical limitations to low-contrast detectability and radiation dose. Proposed methods of x-ray scatter reduction will also be discussed.

Theoretic Basis and Technical Implementations of CT Perfusion in Acute Ischemic Stroke, Part 1: Theoretic Basis

Abstract: CT perfusion (CTP) is a functional imaging technique that provides important information about capillary-level hemodynamics of the brain parenchyma and is a natural complement to the strengths of unenhanced CT and CT angiography in the evaluation of acute stroke, vasospasm, and other neurovascular disorders. CTP is critical in determining the extent of irreversibly infarcted brain tissue (infarct "core") and the severely ischemic but potentially salvageable tissue ("penumbra"). This is achieved by generating parametric maps of cerebral blood flow, cerebral blood volume, and mean transit time.

Hemorrhage in Posterior Reversible Encephalopathy Syndrome: Imaging and Clinical Features

Abstract: BACKGROUND AND PURPOSE: Hemorrhage is known to occur in posterior reversible encephalopathy syndrome (PRES), but the characteristics have not been analyzed in detail. The purpose of this study was to evaluate the imaging and clinical features of hemorrhage in PRES. MATERIALS AND METHODS: Retrospective assessment of 151 patients with PRES was performed, and 23 patients were identified who had intracranial hemorrhage at toxicity. Hemorrhage types were identified and tabulated, including minute focal hemorrhages ( 116 mm Hg). RESULTS: The overall incidence of hemorrhage was 15.2%, with borderline statistical significance noted between the observed clinical associations ( P = .07). Hemorrhage was significantly more common ( P = .02) after allogeneic bone marrow transplantation (allo-BMT) than after solid-organ transplantation. The 3 hemorrhage types were noted with equal frequency. A single hemorrhage type was found in 16 patients, with multiple types noted in 7. Patients undergoing therapeutic anticoagulation were statistically more likely to develop hemorrhage ( P = .04). No difference in hemorrhage incidence was found among the 3 blood pressure subgroups (range, 14.9%–15.9%). CONCLUSIONS: Three distinct types of hemorrhage (minute hemorrhage, sulcal subarachnoid hemorrhage, hematoma) were identified in PRES with equal frequency. The greatest hemorrhage frequency was seen after allo-BMT and in patients undergoing therapeutic anticoagulation. Hemorrhage rate was independent of the toxicity blood pressure.

Dangerous extracranial-intracranial anastomoses and supply to the cranial nerves: vessels the neurointerventionalist needs to know.

Abstract: Transarterial embolization in the external carotid artery (ECA) territory has a major role in the endovascular management of epistaxis, skull base tumors, and dural arteriovenous fistulas. Knowledge of the potential anastomotic routes, identification of the cranial nerve supply from the ECA, and the proper choice of embolic material are crucial to help the interventionalist avoid neurologic complications during the procedure. Three regions along the skull base constitute potential anastomotic routes between the extracranial and intracranial arteries: the orbital, the petrocavernous, and the upper cervical regions. Branches of the internal maxillary artery have anastomoses with the ophthalmic artery and petrocavernous internal carotid artery (ICA), whereas the branches of the ascending pharyngeal artery are connected to the petrocavernous ICA. Branches of both the ascending pharyngeal artery and the occipital artery have anastomoses with the vertebral artery. To avoid cranial nerve palsy, one must have knowledge of the supply to the lower cranial nerves: The petrous branch of the middle meningeal artery and the stylomastoid branch of the posterior auricular artery form the facial arcade as the major supply to the facial nerve, and the neuromeningeal trunk of the ascending pharyngeal artery supplies the lower cranial nerves (CN IX-XII).

White matter involvement in idiopathic Parkinson disease: a diffusion tensor imaging study.

Abstract: BACKGROUND AND PURPOSE: Diffusion tensor imaging (DTI) offers a unique window on the connectivity changes, extending beyond the basal ganglia, which accompany the cognitive symptoms of Parkinson disease (PD). The primary purpose of this study was to assess the microstructural damage to cerebral white matter occurring in idiopathic PD. MATERIALS AND METHODS: Our sample included patients with PD without dementia (n = 10; Hoehn and Yahr stages I and II; Unified Parkinson Disease Rating Scale, 20.5 ± 8.3; and Mini-Mental State Examination, 28.3 ± 1.5) and age-matched healthy control subjects (n = 10). DTI was performed on a 1.5T scanner, and mean diffusivity (MD) and fractional anisotropy (FA) maps were obtained. Regions of interest (ROIs) were drawn on the major fiber bundles as well as on gray matter nuclei. RESULTS: In patients, the MD was increased at borderline significance in the substantia nigra but was unaltered in the thalamus, globus pallidus, putamen, and in the head of the caudate nucleus. The FA and MD were unaltered in the corticospinal tract in the midbrain and at the level of the internal capsule, and in the splenium of the corpus callosum. By contrast, the MD was increased and the FA was decreased in the genu of the corpus callosum and in the superior longitudinal fasciculus; in the cingulum, only the MD was altered. The observed changes were not significantly lateralized. CONCLUSIONS: Widespread microstructural damage to frontal and parietal white matter occurs already in the early stages of PD.

Diffusion-Weighted Echo-Planar MR Imaging of Primary Parotid Gland Tumors: Is a Prediction of Different Histologic Subtypes Possible?

Abstract: BACKGROUND AND PURPOSE: Our aim was to determine the value of echo-planar diffusion-weighted MR imaging (epiDWI) in differentiating various types of primary parotid gland tumors. MATERIALS AND METHODS: One hundred forty-nine consecutive patients with suspected tumors of the parotid gland were examined with an epiDWI sequence by using a 1.5T unit. Image analysis was performed by 2 radiologists independently, and the intraclass correlation coefficient was computed. Histologic diagnosis was obtained in every patient. For comparison of apparent diffusion coefficients (ADCs), a paired 2-tailed Student t test with a Bonferroni correction was used. RESULTS: In 136 patients, a primary parotid gland tumor was confirmed by histology. Among the observers, a high correlation was calculated (0.98). ADC values of pleomorphic adenomas were significantly higher than those of all other entities, except for myoepithelial adenomas (P = .054). ADC values of Warthin tumors were different from those of myoepithelial adenomas, lipomas, and salivary duct carcinomas (P CONCLUSION: epiDWI has the potential to differentiate pleomorphic adenoma and myoepithelial adenomas from all other examined entities. Due to an overlap not only within the group of benign and malignant lesions but also between groups, diagnoses should not be addressed on the basis of ADC values solely. Therefore, further studies combining DWI, morphologic criteria, and probably other MR imaging techniques seem warranted.

Theoretic Basis and Technical Implementations of CT Perfusion in Acute Ischemic Stroke, Part 2: Technical Implementations

Abstract: CT perfusion (CTP) is a functional imaging technique that provides important information about capillary-level hemodynamics of the brain parenchyma and is a natural complement to the strengths of unenhanced CT and CT angiography in the evaluation of acute stroke, vasospasm, and other neurovascular disorders. CTP is critical in determining the extent of irreversibly infarcted brain tissue (infarct "core") and the severely ischemic but potentially salvageable tissue ("penumbra"). This is achieved by generating parametric maps of cerebral blood flow, cerebral blood volume, and mean transit time.

A Second-Generation, Endoluminal, Flow-Disrupting Device for Treatment of Saccular Aneurysms

Abstract: BACKGROUND AND PURPOSE: We report a preclinical study of a second-generation endoluminal device (Pipeline Embolization Device [PED-2] for aneurysmal occlusion and compare the PED-2 with its first-generation predecessor (PED-1). MATERIALS AND METHODS: Our Institutional Animal Care and Use Committee approved all studies. The PED-2 is a braided endoluminal, flow-diverting device and was implanted across the necks of 18 elastase-induced aneurysms in New Zealand white rabbits and followed for 1 month ( n = 6), 3 months ( n = 6), and 6 months ( n = 6). A second PED-2 was implanted in the abdominal aorta to cover the origins of the lumbar arteries. Angiographic occlusion rates were documented as complete, near-complete, and incomplete. Parent artery percent diameter stenosis was calculated. Results were compared with a previous publication focused on the PED-1, with use of the same model. We compared ordinal outcomes using Fisher Exact or χ 2 tests. We compared continuous data using analysis of variance. RESULTS: Occlusion rates (complete and incomplete) for the PED-2 were noted in 17 cases (94%) and 1 (6%), respectively, compared with 9 cases of complete (53%) and 8 (47%) of incomplete occlusion with the PED-1 ( P = .0072). No incidents of branch artery occlusion or distal emboli in vessels downstream of the parent artery were observed with the PED-2. Parent artery neointimal hyperplasia was minimal in most cases and was significantly less than in the PED-1. CONCLUSIONS: The PED-2 is a biocompatible and hemocompatible device that occludes saccular aneurysms while preserving the parent artery and small-branch vessels in our animal model.

Side matters: diffusion tensor imaging tractography in left and right temporal lobe epilepsy.

Abstract: BACKGROUND AND PURPOSE: Noninvasive imaging plays a pivotal role in lateralization of the seizure focus in presurgical patients with temporal lobe epilepsy (TLE). Our goal was to evaluate the utility of diffusion tensor imaging (DTI) tractography in TLE. MATERIALS AND METHODS: Twenty-one patients with TLE (11 right, 10 left TLE) and 21 controls were enrolled. A 1.5T MR imaging scanner was used to obtain 51 diffusion-gradient-direction images per subject. Eight pairs of white matter fiber tracts were traced, and fiber tract fractional anisotropy (FA) was calculated and compared with controls. Fiber tract FA asymmetry and discriminant function analysis were evaluated in all subjects and fiber tracts respectively. RESULTS: Compared with controls, patients with TLE demonstrated decreased FA in 5 ipsilateral fiber tracts. Patients with left TLE had 6 ipsilateral and 4 contralateral fiber tracts with decreased FA. Patients with right TLE had 4 ipsilateral but no contralateral tracts with decreased FA compared with controls. Right-sided FA asymmetry was demonstrated in patients with right TLE for 5 fiber tracts, and left-sided asymmetry, for patients with left TLE for 1 fiber tract. Discriminant function analysis correctly categorized patients into left-versus-right TLE in 90% of all cases (100% correct in all patients without hippocampal sclerosis) by using uncinate fasciculus and parahippocampal fiber tracts. CONCLUSIONS: We found widespread reductions in fiber tract FA in patients with TLE, which were most pronounced ipsilateral to the seizure focus. Patients with left TLE had greater, more diffuse changes, whereas patients with right TLE showed changes that were primarily ipsilateral. Disease was lateralized to a high degree independent of identifiable hippocampal pathology noted on conventional MR imaging.

First Clinical Study on Ultra-High-Field MR Imaging in Patients with Multiple Sclerosis: Comparison of 1.5T and 7T

Abstract: BACKGROUND AND PURPOSE: Higher magnetic field strengths and continuous improvement of high-resolution imaging in multiple sclerosis (MS) are expected to provide unique in-vivo and non-invasive insights in pathogenesis and clinical monitoring. The purpose of this study was to investigate the potential of high-resolution imaging of MS lesions in vivo comparing 7T with conventional 1.5T. MATERIALS AND METHODS: Twelve consecutive patients with clinically definite MS were scanned on a 7T whole-body scanner and on a 1.5T Avanto. The 1.5T and 7T imaging protocol consisted of high-resolution axial proton density (PD) + T2-weighted turbo spin-echo and T2*-weighted gradient-echo (GRE), and sagittal T1-weighted 3D magnetization-prepared rapid acquisition of gradient echo. RESULTS: The sequence parameters at 7T had to be modified because of specific absorption rate (SAR) restrictions while keeping contrast parameters equivalent to 1.5T. White matter lesions were better detected and delineated from adjacent structures at 7T compared with 1.5T. There were 42% of the patients who showed additional lesions at 7T: there were 97 white matter lesions detected on 1.5T versus 126 lesions at 7T, an increase of 23%. The perivascular migration of MS lesions was well visualized on T2*-weighted GRE sequences. In larger lesions (10 mm), a multilayer structure was revealed on T2*-weighted GRE not seen at 1.5T. Because of the higher resolution, it was possible to differentiate between juxtacortical white matter lesions and cortical lesions. There were 44% of the subcortical lesions depicted at 7T that showed cortical involvement. CONCLUSIONS: Ultra-high-field imaging of patients with MS at 7T was well tolerated and provided better visualization of MS lesions in the gray matter and demonstrated structural abnormalities within the MS lesions themselves more effectively.

Correlation of MR imaging findings and clinical manifestations in neurosarcoidosis.

Abstract: BACKGROUND AND PURPOSE: MR imaging is widely used for the diagnosis and follow-up of neurosarcoidosis lesions. However, the temporal evolution of imaging abnormalities and the prognostic significance of imaging features is not well understood. We undertook a retrospective study of patients with biopsy-proved or clinically diagnosed neurosarcoidosis for the following reasons: 1) to assess concordance between abnormalities noted on MR imaging with neurologic symptoms at presentation; 2) to correlate changes in imaging findings during follow-up with clinical improvement or worsening; and 3) to identify imaging features that may have prognostic significance. MATERIALS AND METHODS: We reviewed radiologic records from 1999 to 2008 of patients with biopsy-proved or clinically diagnosed neurosarcoidosis and correlated MR imaging findings in these patients with their demographic characteristics, clinical features, and symptomatic responses during follow-up. RESULTS: Thirty-two patients were included in the study. Cranial nerve lesions and leptomeningeal disease identified on MR imaging were symptomatic in 64% patients, dural lesions were associated with symptoms in 28% patients, but nonenhancing white matter lesions did not have correlating symptoms. During follow-up, MR imaging findings generally changed in concordance with the change in clinical symptoms (80% patients). Cranial nerve enhancement (9/11) and spinal lesions (5/8) were most likely to resolve with clinical improvement, whereas dural lesions (6/11), enhancing parenchymal lesions (3/7), and non-enhancing parenchymal lesions (0/4) were less likely to change during therapy. Patients with ≥1 enhancing T2-hypointense lesion (4/7, 57%) were less likely to show clinical improvement than those without such lesions (12/13, 92%). CONCLUSIONS: Although many sarcoid-related MR imaging abnormalities were not associated with correlating symptoms at presentation, there was a high degree of concordance between changes in clinical symptoms and MR imaging abnormalities during follow-up. Enhancing T2-hypointense dural and parenchymal lesions were associated with suboptimal imaging and clinical response to immunosuppressive therapy.

Fully-Automated Quantification of Regional Brain Volumes for Improved Detection of Focal Atrophy in Alzheimer Disease

Abstract: Volumetric analysis of structural MR images of the brain may provide quantitative evidence of neurodegeneration and help identify patients at risk for rapid clinical deterioration. This note describes tests of a fully automated MR imaging postprocessing system for volumetric analysis of structures (such as the hippocampus) known to be affected in early Alzheimer disease (AD). The system yielded results that correlated highly with independent computer-aided manual segmentation and were sensitive to the anatomic atrophy characteristic of mild AD.

The Acetazolamide Challenge: Techniques and Applications in the Evaluation of Chronic Cerebral Ischemia

Abstract: The acetazolamide (ACZ) challenge test is a useful clinical tool and a reliable predictor of critically reduced perfusion. In patients with chronic steno-occlusive disease, the ability to maintain normal cerebral blood flow by reducing vascular resistance secondary to autoregulatory vasodilation is compromised. Identification of the presence and degree of autoregulatory vasodilation (reflecting the cerebrovascular reserve) is a significant prognostic factor in patients with chronic cerebrovascular disease. The pharmacologic challenge of a vasodilatory stimulus such as ACZ can also be used to optimize the treatment strategies for these patients. The pathophysiology, methods, and clinical applications of the ACZ challenge test are discussed in this article.

Lyme Neuroborreliosis: Manifestations of a Rapidly Emerging Zoonosis

Abstract: Lyme disease has a worldwide distribution and is the most common vector-borne disease in the United States. Incidence, clinical manifestations, and presentations vary by geography, season, and recreational habits. Lyme neuroborreliosis (LNB) is neurologic involvement secondary to systemic infection by the spirochete Borrelia burgdorferi in the United States and by Borrelia garinii or Borrelia afzelii species in Europe. Enhanced awareness of the clinical presentation of Lyme disease allows inclusion of LNB in the imaging differential diagnosis of facial neuritis, multiple enhancing cranial nerves, enhancing noncompressive radiculitis, and pediatric leptomeningitis with white matter hyperintensities on MR imaging. The MR imaging white matter appearance of successfully treated LNB and multiple sclerosis display sufficient similarity to suggest a common autoimmune pathogenesis for both. This review highlights differences in the epidemiology, clinical manifestations, diagnosis, and management of Lyme disease in the United States, Europe, and Asia, with an emphasis on neurologic manifestations and neuroimaging.

Angiography reveals that fluid-attenuated inversion recovery vascular hyperintensities are due to slow flow, not thrombus.

Abstract: BACKGROUND AND PURPOSE: Fluid-attenuated inversion recovery (FLAIR) vascular hyperintensities (FVH) are commonly encountered on MR imaging studies performed shortly after the onset of acute ischemic stroke. Prior reports have speculated regarding the pathogenesis of this finding, yet definitive correlative angiographic studies have not been performed. We studied the pathophysiologic and hemodynamic correlates of FVH on conventional angiography and concurrent MR imaging sequences. MATERIALS AND METHODS: Retrospective review of FLAIR and gradient-refocused echo MR imaging sequences acquired immediately before conventional angiography for acute stroke was conducted in a blinded fashion. The presence, location, and morphology of FVH were noted and correlated with markers of thrombotic occlusion and collateral flow on angiography. Angiographic collaterals were graded on a 5-point scale incorporating extent and hemodynamic aspects. RESULTS: A prospective ischemic stroke registry of 632 patients was searched to identify 74 patients (mean age, 63.4 ± 20 years; 48% women) having undergone FLAIR sequences immediately before angiography. Median time from FLAIR to angiography was 2.9 hours (interquartile range, 1.1–4.7 hours). FVH were present in 53/74 (72%) of all acute stroke cases with subsequent angiography. FVH distal to an arterial occlusion were associated with a high grade of leptomeningeal collateral blood flow. CONCLUSIONS: FVH are observed in areas of blood flow proximal and distal to stenosis or occlusion and are noted with more extensive collateral circulation.

Alterations in cortical thickness and white matter integrity in mild cognitive impairment measured by whole-brain cortical thickness mapping and diffusion tensor imaging.

Abstract: BACKGROUND AND PURPOSE: Mild cognitive impairment (MCI) is a risk factor for Alzheimer disease and can be difficult to diagnose because of the subtlety of symptoms. This study attempted to examine gray matter (GM) and white matter (WM) changes with cortical thickness analysis and diffusion tensor imaging (DTI) in patients with MCI and demographically matched comparison subjects to test these measurements as possible imaging markers for diagnosis. MATERIALS AND METHODS: Subjects with amnestic MCI (n = 10; age, 72.2 ± 7.1 years) and normal cognition (n = 10; age, 70.1 ± 7.7 years) underwent DTI and T1-weighted MR imaging at 3T. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), and cortical thickness were measured and compared between the MCI and control groups. We evaluated the diagnostic accuracy of 2 methods, either in combination or separately, using binary logistic regression and nonparametric statistical analyses for sensitivity, specificity, and accuracy. RESULTS: Decreased FA and increased ADC in WM regions of the frontal and temporal lobes and corpus callosum (CC) were observed in patients with MCI. Cortical thickness was decreased in GM regions of the frontal, temporal, and parietal lobes in patients with MCI. Changes in WM and cortical thickness seemed to be more pronounced in the left hemisphere compared with the right hemisphere. Furthermore, the combination of cortical thickness and DTI measurements in the left temporal areas improved the accuracy of differentiating MCI patients from control subjects compared with either measure alone. CONCLUSIONS: DTI and cortical thickness analyses may both serve as imaging markers to differentiate MCI from normal aging. Combined use of these 2 methods may improve the accuracy of MCI diagnosis.

Endovascular Approaches to Acute Stroke, Part 1: Drugs, Devices, and Data

Abstract: Despite years of research and pioneering clinical work, stroke remains a massive public health concern. Since 1996, we have lived in the era of US Food and Drug Administration-approved intravenous (i.v.) recombinant tissue plasminogen activator (rtPA). This treatment, despite its promise, continues to exhibit its limitations. Endovascular therapy has several theoretic advantages over i.v. rtPA, including site specificity, longer treatment windows, and higher recanalization rates. In this article, we will review the various pharmacologic strategies for acute stroke treatment, providing both a historic context and the state of the art. The drugs will be classified on the basis of their theoretic rationale for therapy. Next, we will review the various devices and strategies for mechanical revascularization with an aim toward comprehensiveness. These range from wire disruption of thrombus to preclinical trials for novel mechanical solutions. This first installment of this 2-part series will end with an analysis of retrograde reperfusion techniques.

CT Angiography for Brain Death Diagnosis

Abstract: BACKGROUND AND PURPOSE: Lack of cerebral circulation is an important confirmatory test for brain death (BD). Conventional angiography remains the standard imaging method, but CT angiography (CTA) is emerging as an alternative. France accepts BD diagnoses relying on a score based on lack of opacification of 7 intracerebral vessels in CTA images. The purpose of this study was to validate the efficiency of this score and to evaluate the sensitivity of a novel 4-point CTA score in confirming BD. MATERIALS AND METHODS: A prospective multicentric study was conducted during 12 months with 105 patients referred for CTA to confirm a clinical diagnosis of BD. Clinical data were recorded. CTA images were interpreted first by local radiologists at the referent center, resulting in a 7-point score based on lack of opacification of the pericallosal and cortical segments of the middle cerebral arteries (MCAs), internal cerebral veins (ICVs), and 1 great cerebral vein per patient and, second, by a consensus panel of 3 expert radiologists, blinded to the initial scores, resulting in novel 4-point scores based on the lack of opacification of the cortical segments of the MCAs and ICVs. RESULTS: Injection of contrast medium did not alter renal function. With the initial 7-point score, sensitivity was 62.8%. With the simplified 4-point score, sensitivity was 85.7% and specificity was 100%. Opacification of ICVs was absent in 98.1% of patients. CONCLUSIONS: Lack of opacification in the cortical segments of the MCAs and internal veins in CTA is efficient and reliable for confirming BD.

A Radiologic Score to Distinguish Autoimmune Hypophysitis from Nonsecreting Pituitary Adenoma Preoperatively

Abstract: BACKGROUND AND PURPOSE: Autoimmune hypophysitis (AH) mimics the more common nonsecreting pituitary adenomas and can be diagnosed with certainty only histologically. Approximately 40% of patients with AH are still misdiagnosed as having pituitary macroadenoma and undergo unnecessary surgery. MR imaging is currently the best noninvasive diagnostic tool to differentiate AH from nonsecreting adenomas, though no single radiologic sign is diagnostically accurate. The purpose of this study was to develop a scoring system that summarizes numerous MR imaging signs to increase the probability of diagnosing AH before surgery. MATERIALS AND METHODS: This was a case-control study of 402 patients, which compared the presurgical pituitary MR imaging features of patients with nonsecreting pituitary adenoma and controls with AH. MR images were compared on the basis of 16 morphologic features besides sex, age, and relation to pregnancy. RESULTS: Only 2 of the 19 proposed features tested lacked prognostic value. When the other 17 predictors were analyzed jointly in a multiple logistic regression model, 8 (relation to pregnancy, pituitary mass volume and symmetry, signal intensity and signal intensity homogeneity after gadolinium administration, posterior pituitary bright spot presence, stalk size, and mucosal swelling) remained significant predictors of a correct classification. The diagnostic score had a global performance of 0.9917 and correctly classified 97% of the patients, with a sensitivity of 92%, a specificity of 99%, a positive predictive value of 97%, and a negative predictive value of 97% for the diagnosis of AH. CONCLUSIONS: This new radiologic score could be integrated into the management of patients with AH, who derive greater benefit from medical as opposed to surgical treatment.

Intracranial Aneurysms in Childhood: 27-Year Single-Institution Experience

Abstract: BACKGROUND AND PURPOSE: Pediatric aneurysms are rare and, thus, relatively poorly understood as compared to those in adults. Our aim was to characterize the clinical, imaging, treatment, and outcome data of patients younger than 19 years diagnosed with intracranial aneurysms at a tertiary care institution. MATERIALS AND METHODS: We performed a retrospective medical record review of pediatric patients examined at our university hospital between 1981 and 2008. RESULTS: We evaluated 77 patients (mean age, 12 years; 40 female, 37 male) with 103 intracranial aneurysms. Patients presented with headache (45%), cranial neuropathies (16%), nausea/vomiting (15%), vision changes (13%), trauma (13%), seizure (4%), or sensory changes (3%). Subarachnoid hemorrhage occurred in 25 patients. Thirty-one fusiform aneurysms occurred in 25 patients. Forty-seven saccular aneurysms occurred in 35 patients. Twelve infectious aneurysms occurred in 6 patients. Fifteen traumatic aneurysms occurred in 12 patients. Fifty-nine patients underwent treatment of their aneurysms; 18 patients’ conditions were managed conservatively. Nineteen patients underwent primary endovascular coiling, 1 patient had endovascular stent-assisted coiling, 11 patients underwent endovascular parent artery occlusion, 19 patients underwent surgical clipping, and 10 patients had aneurysms trapped and bypassed. Mortality was 1.3%. Morbidity included 8% infarction and 4% new-onset seizures. Six patients developed new aneurysms or had enlargement of untreated aneurysms. CONCLUSIONS: In our experience, intracranial aneurysms of childhood show a female predilection and predominantly saccular morphology. In neurovascular centers where microneurosurgical and endovascular options are available, most children with intracranial aneurysms can be successfully treated with low morbidity and mortality. Fusiform aneurysms require a combined microneurosurgical and endovascular approach more often than saccular aneurysms. The development of new aneurysms in pediatric patients during limited follow-up warrants further investigation.

CT and MR Imaging Features of Primary Central Nervous System Lymphoma in Norway, 1989-2003

Abstract: BACKGROUND AND PURPOSE: Studying imaging findings of non–acquired immunodeficiency syndrome (AIDS) primary central nervous system lymphoma (PCNSL), we hypothesized that the imaging presentation has changed with the increasing incidence of PCNSL and is related to clinical factors (eg, time to diagnosis and the patient9s being diagnosed alive or at postmortem examination). MATERIALS AND METHODS: Chart and histologic reviews of patients recorded as having PCNSL during 1989–2003 in the Norwegian Cancer Registry identified 98 patients with non-AIDS PCNSL; 75 had available imaging. CT and MR images from the first diagnostic work-up after onset of symptoms but before histologic diagnosis were reviewed. RESULTS: CT and/or MR imaging in the 75 patients revealed no lesion in 10 (13%), a single focal lesion in 34 (45%), multiple focal lesions in 26 (35%), and disseminated lesions in 5 (7%) patients. All together, we identified 103 focal lesions (single/multiple): 63% in white matter, 56% abutting the ventricular surface, and 43% in the frontal lobes); 100% (102/102 lesions evaluated with contrast) showed contrast enhancement. The median time from imaging to diagnosis for patients with no, single, multiple, or disseminated lesions was 32, 3, 5, and 3 weeks, respectively (P = .01). Patients with no or disseminated lesions were more often diagnosed at postmortem examination (P = .06). Imaging findings were practically unchanged during the consecutive 5-year periods. CONCLUSIONS: White matter periventricular contrast-enhancing single or multiple focal lesions were typical of non-AIDS PCNSL. No or disseminated lesions heightened the risk of delayed or postmortem diagnosis. Although the incidence of non-AIDS PCNSL has increased, its presentation at imaging remains unchanged.

Clinical and Angiographic Results of Coiling of 196 Very Small (≤ 3 mm) Intracranial Aneurysms

Abstract: BACKGROUND AND PURPOSE: Coiling of very small (≤ 3 mm) aneurysms is considered controversial because of technical difficulties and a higher rate of procedural aneurysm ruptures. In this study, we report clinical and angiographic results of coiling of aneurysms 3 mm or smaller in comparison with larger aneurysms in a large, single-center cohort of patients. MATERIALS AND METHODS: Between 1995 and July 2008, a total of 1295 aneurysms were selectively occluded with coils. Of 1295 aneurysms, 196 (15.1%) in 187 patients were very small. Of 196 aneurysms, 149 (76%) had ruptured and 47 (24%) had not ruptured. There were 51 males (27%) and 136 females (73%). Mean age was 54.7 years (age range, 11–78 years). RESULTS: Procedural morbidity rate was 2.1% and mortality rate, 1.1%. Procedural rupture occurred in 15 of 196 aneurysms (7.7%). In 13 of 15 procedural ruptures, this had no adverse effect on outcome. Early recurrent hemorrhage of the coiled aneurysm occurred in 2 patients (1.1%). Compared with larger aneurysms, in very small aneurysms more often a procedural rupture occurred (7.7% versus 3.6%; P = .018). Procedural morbidity rate was lower (3.2% versus 5.5%), but this was not significant ( P = .26). Retreatment rate consisted predominantly of clipping soon after incomplete coiling and was lower than in larger aneurysms (5.1% versus 10.0%; P = .041). Other characteristics were not significantly different. CONCLUSIONS: Coiling of very small aneurysms was technically feasible, with good results. Although procedural aneurysm rupture was significantly more frequent in very small aneurysms, this did not lead to increased overall morbidity and mortality rates. Retreatment rate was lower than for larger aneurysms.

Imaging Lesions of the cavernous sinus

Abstract: Our aim was to review the imaging findings of relatively common lesions involving the cavernous sinus (CS), such as neoplastic, inflammatory, and vascular ones. The most common are neurogenic tumors and cavernoma. Tumors of the nasopharynx, skull base, and sphenoid sinus may extend to the CS as can perineural and hematogenous metastases. Inflammatory, infective, and granulomatous lesions show linear or nodular enhancement of the meninges of the CS but often have nonspecific MR imaging features. In many of these cases, involvement elsewhere suggests the diagnosis. MR imaging is sensitive for detecting vascular lesions such as carotid cavernous fistulas, aneurysms, and thromboses.

Difficult aneurysms for endovascular treatment: overwide or undertall?

Abstract: BACKGROUND AND PURPOSE: Aneurysm geometry has been shown to predict the need for adjunctive techniques in the endovascular treatment of intracranial aneurysms. We conducted a systematic retrospective study examining which thresholds of dome-to-neck ratio, maximum neck width, and aspect ratio of intracranial aneurysms best predict the need for adjunctive techniques in endovascular management. MATERIALS AND METHODS: One hundred seventy-five consecutive patients who were selected for attempted embolization of 185 intracranial aneurysms were included in this study. Aneurysm dome-to-neck ratio (maximum dome width/maximum neck width), maximum neck width, and aspect ratio (dome height/maximum neck width) were measured on 2D digital subtraction angiography. Statistical analysis was conducted to determine which thresholds of dome-to-neck ratio, maximum neck width, and aspect ratio were most predictive of the need for adjunctive devices in endovascular management of these aneurysms. RESULTS: We demonstrated that 75% of aneurysms with dome-to-neck ratios >1.6 ( P 1.6 ( P P P = .02) and 89% of aneurysms with aspect ratios P P = .0004). CONCLUSIONS: Aneurysms with aspect and dome-to-neck ratios >1.6 usually did not require adjunctive techniques. Aneurysms with aspect and dome-to-neck ratios

Clinical and angiographic follow-up of stent-only therapy for acute intracranial vertebrobasilar dissecting aneurysms

Abstract: BACKGROUND AND PURPOSE: Little has been known about the clinical and angiographic follow-up results of stent-only therapy for intracranial vertebrobasilar dissecting aneurysms (VBDA). The purpose of this study was to evaluate the feasibility, safety, clinical, and angiographic follow-up of stent-only therapy for VBDA. MATERIALS AND METHODS: Twenty-seven patients with 29 VBDAs (11 ruptured, 18 unruptured), not suitable for deconstructive treatment, underwent stent-only therapy. Feasibility, safety, clinical, and angiographic follow-up were retrospectively evaluated. Angiographic outcomes were compared between single-stent and multiple-stent groups. RESULTS: All attempted stent placements were successfully accomplished without any treatment-related complication. Of the 11 ruptured VBDAs, 4 were treated by single stents, 6 by double overlapping stents, and 1 by triple overlapping stents. Of the 18 unruptured VBDAs, 6 were treated by stents, and 12 by double overlapping stents. One patient with a ruptured VBDA, treated by single stent, had rebleeding and died. None of the remaining patients had posttreatment bleeding during follow-up (mean, 28 months; range, 7–50 months). Eight patients with ruptured VBDA and all patients with unruptured VBDA had excellent outcomes (modified Rankin Scale, 0–1). The remaining 2 patients with ruptured VBDA were moderately disabled because of the initial damage. Angiographic follow-up was available in 27 VBDAs, 4 to 42 months (mean, 12 months) after treatment. Follow-up angiograms revealed complete obliteration of the dissecting aneurysm in 12, partial obliteration in 12, stable in 1, enlargement in 1, and in-stent occlusion in 1. Angiographic improvement (complete or partial obliteration) was more frequent in the multiple-stent group (17/17) than in the single-stent group (7/9; P CONCLUSIONS: In this small series, stent-only therapy was safe and effective in the treatment of VBDAs that were not deemed suitable for treatment with parent-artery occlusion.

The Effect of Exercise on the Cerebral Vasculature of Healthy Aged Subjects as Visualized by MR Angiography

Abstract: BACKGROUND AND PURPOSE: Prior studies suggest that aerobic exercise may reduce both the brain atrophy and the decline in fractional anisotropy observed with advancing age. It is reasonable to hypothesize that exercise-induced changes to the vasculature may underlie these anatomic differences. The purpose of this blinded study was to compare high-activity and low-activity healthy elderly volunteers for differences in the cerebrovasculature as calculated from vessels extracted from noninvasive MR angiograms (MRAs). MATERIALS AND METHODS: Fourteen healthy elderly subjects underwent MRA. Seven subjects reported a high level of aerobic activity (64 ± 5 years of age; 5 men, 2 women) and 7, a low activity level (68 ± 6 years of age; 5 women, 2 men). Following vessel segmentation from MRA by an individual blinded to subject activity level, quantitative measures of vessel number, radius, and tortuosity were calculated and histogram analysis of vessel number and radius was performed. RESULTS: Aerobically active subjects exhibited statistically significant reductions in vessel tortuosity and an increased number of small vessels compared with less active subjects. CONCLUSIONS: Aerobic activity in elderly subjects is associated with lower vessel tortuosity values and an increase in the number of small-caliber vessels. It is possible that an aerobic exercise program may contribute to healthy brain aging. MRA offers a noninvasive approach to visualizing the cerebral vasculature and may prove useful in future longitudinal investigations.