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Bruce A Wasserman

Publications and source records attributed to Bruce A Wasserman.

18 recordsLinked to original sources
PubMed2007

Comparison of gadolinium-enhanced cardiovascular magnetic resonance angiography with high-resolution black blood cardiovascular magnetic resonance for assessing carotid artery stenosis.

PURPOSE: Carotid angiography is used to assess stroke risk, but it cannot reliably characterize plaque burden because the vessel remodels during plaque formation. High-resolution black blood cardiovascular magnetic resonance (BBCMR) depicts the outer wall thereby providing a truer estimate of plaque size. We compared carotid stenosis by gadolinium enhancement cardiovascular magnetic resonance angiography (CMRA) versus high-resolution BBCMR. METHODS: Twenty-four subjects (M:F = 20:4; ages 57-83 years) with carotid atherosclerosis underwent CMRA and transaxial BBCMR through the stenosis. Area and diameter stenosis measurements by NASCET criteria using CMRA images were compared to area stenosis measurements based on outer wall and lumen contours drawn on corresponding BBCMR images. RESULTS: Area stenosis by CMRA correlated with area stenosis by BBCMR (r = 0.77; 95% CI: 0.58, 0.89). BBCMR values exceeded corresponding CMRA area measurements in 20 of 24 cases, with the remainder being highly stenotic (> 90%). CONCLUSION: CMRA yields lower estimates of luminal narrowing compared to BBCMR, which delineates the outer wall and accounts for vascular remodeling. BBCMR could serve as a new measure of narrowing to guide management, but prospective studies are needed to better understand the clinical implications of this new scale of disease.

Aged↗
PubMed2006

An integrated automated analysis method for quantifying vessel stenosis and plaque burden from carotid MRI images: combined postprocessing of MRA and vessel wall MR.

BACKGROUND AND PURPOSE: We report the evaluation of a semiautomated method for in vivo assessment of the severity of carotid atherosclerosis with minimal user interaction that combines 3-dimensional contrast-enhanced magnetic resonance angiography (CE-MRA) and vessel wall magnetic resonance imaging (MRI). METHODS: Lumen and outer-wall contours were automatically detected, and stenosis and plaque burden were estimated. The method was tested on 22 subjects (352 postcontrast, T1-weighted cross sections and 3-dimensional CE-MRA). RESULTS: We observed good correlation with expert contours: lumen and outer-wall area (r=0.96) and the degree of stenosis (r=0.97). CONCLUSIONS: The fusion of MRA and MRI reduces user interaction and improves contour detection, providing reproducible parameters to assess the severity of atherosclerosis.

Aged↗
PubMed2005

Low-grade carotid stenosis: looking beyond the lumen with MRI.

BACKGROUND AND PURPOSE: The management of carotid atherosclerosis is well-established for symptomatic stenosis above 69%, but the optimal approach for managing lower degrees of narrowing remains uncertain. Because the risk of stroke increases with higher grades of stenosis, we are inclined to consider low-grade disease to be low risk. This approach, however, does not take into account other factors such as plaque size or composition. Plaque may progress to a substantial size before it demonstrates significant stenosis by angiography. We know that low-grade disease can result in cerebrovascular ischemic events, but predicting vulnerable lesions has not been possible by relying on stenosis alone. SUMMARY OF REVIEW: An understanding of the clinical behavior of plaque causing little to no narrowing is now possible with the advent of high-resolution black blood MRI, a modality that does not rely on luminal narrowing for detection. CONCLUSIONS: We present the current understanding of the clinical implications of low-grade carotid stenosis with an example of the MRI assessment of high-risk carotid plaque causing minimal narrowing that highlights the importance of looking beyond the lumen.

Aged↗
PubMed2005

Wash-in kinetics for gadolinium-enhanced magnetic resonance imaging of carotid atheroma.

PURPOSE: To determine the wash-in kinetics of intravenous gadolinium into the fibrous cap and lipid core of carotid atheroma, and identify the time following gadolinium administration that maximizes contrast between the cap and core. MATERIALS AND METHODS: Seven subjects with carotid artery stenosis were studied. Magnetic resonance (MR) images of the atheroma were acquired using a single-inversion-recovery fast-spin-echo (IR FSE) sequence, which was serially repeated during the first 30 minutes following intravenous gadolinium administration. Postcontrast time was divided into three intervals: <10, 11-20, and >21 minutes. Adjusted signal intensity (SI), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) values for postcontrast images were compared to adjusted precontrast values. RESULTS: The mean SNRs of the cap and core were significantly elevated in each postcontrast interval compared with mean precontrast values. The CNRs of the cap vs. the core increased by 19.8% (3.03 to 4.14, P = 0.03) in the first 10 minutes following gadolinium administration, and remained elevated over the next two intervals with a slight decrease in the final interval. CONCLUSION: Increased signal and contrast between the cap and core can be achieved by imaging up to 30 minutes following gadolinium administration, with peak enhancement occurring in the first 10 minutes.

Aged↗
PubMed2005

Anthropometric data for magnetic resonance imaging of the carotid bifurcation.

PURPOSE: To provide anthropometric data applicable to the design of protocols for high-resolution magnetic resonance imaging (MRI) of the carotid bifurcation, particularly those aimed at elucidating the role of local factors in carotid atherogenesis. MATERIALS AND METHODS: Axial black-blood MR images of the carotid bifurcation were acquired from 25 young, healthy volunteers and 25 older, asymptomatic patients, from which were measured a variety of quantities related to the orientation and placement of the bifurcation within the neck. RESULTS: Descriptive statistics were obtained for the following quantities: separation of the bifurcation apices within (57.8+/-6.7 mm) and between (4.9+/-4.1 mm) axial slices; orientation of the bifurcation within the axial plane (31.7+/-26.9 degrees ), and of the common carotid artery (CCA) relative to the sagittal (7.5+/-7.1 degrees ) and coronal (7.9+/-7.8 degrees ) planes; depth of the bifurcation from the skin surface (29.5+/-7.2 mm); and neck width (125.9+/-14.4 mm). CONCLUSION: In most cases, both carotid arteries may be captured, without aliasing, within a 12-cm field-of-view axial image; however, the two apices will rarely be captured within the same axial slice. The CCA is significantly oblique to the body axis, but at angles sufficiently acute to permit the use of axial slices. Finally, a significant linear relationship between neck width and carotid depth may be used to inform radio frequency (RF) coil selection prior to scanning a subject, and hence facilitate optimal imaging in light of the wide anatomic variations observed.

Adult↗
PubMed2005

Vulnerable plaque imaging.

The concept of vulnerable plaque is well established with increasing evidence from clinical and basic research. The paradigm has shifted from focusing exclusively on the hemodynamic effects of plaque (ie, resulting lumenal stenosis alone as a predictor of stroke risk) to assessment of the structure and composition of plaque (eg, denuded endothelium with inflammatory elements as a nidus for platelet-fibrin clumping). It is increasingly evident that methods to detect and characterize vulnerable plaque must be developed and optimized. Although MR imaging, CT, and ultrasound provide data regarding single lesions, future investigations relying heavily on nuclear medicine techniques may offer functional assessment of the entire cardiovascular system.

Arteriosclerosis↗
PubMed2005

Human peripheral arteries: feasibility of transvenous intravascular MR imaging of the arterial wall.

Feasibility of in vivo transvenous intravascular magnetic resonance (MR) imaging of the human arterial wall was determined. All subjects provided written informed consent, and institutional review board approved the study. Six arteries in six patients were imaged with a guidewire placed in the iliac vein (n = 5) or left renal vein (n = 1). Pre- and postcontrast T1-weighted and T2-weighted transvenous MR imaging were performed. An atherosclerotic plaque with a fibrous cap was identified on 27 (42%) of 64 images of veins without stents; intimal hyperplasia in a renal artery with a stent was identified on 12 images. Contrast-to-noise ratios (CNRs) on arterial wall postcontrast T1-weighted images were superior to those on images obtained with other sequences (P < .001), and the postcontrast images demonstrated the greatest number of plaques with a low-signal intensity core and fibrous cap. Preliminary results show that transvenous MR imaging is feasible for high-spatial-resolution imaging of the arterial wall and atherosclerotic plaque. Postcontrast T1-weighted imaging affords greatest CNR for the arterial wall.

Aged↗
PubMed2005

Use of magnetic resonance imaging in differentiating compartmental location of spinal tumors.

Magnetic resonance imaging (MRI) is the best imaging modality for evaluating most spinal tumors. In this review, we describe the MRI appearance of extradural, intradural-extramedullary, and intradural-intramedullary tumors as well as the image interpretation techniques that permit identification of the compartment in which a lesion is located. In addition, we review the literature and our experience in using an anatomic classification system to narrow the differential diagnosis for patients with spine tumors. This method permits successful identification of a narrow differential diagnosis, which can be used to guide additional evaluation and treatment.

Contrast Media↗
PubMed2003

Cavernous carotid artery calcification and white matter ischemia.

BACKGROUND AND PURPOSE: The relevance of cavernous carotid artery calcification on unenhanced CT scans of the brain has recently been investigated against the backdrop of the widespread implementation of coronary artery calcification scoring. We sought to determine whether the degree of cavernous carotid artery calcification correlated with scores of white matter hyperintensity seen on MR images. In so doing, we sought to establish a relative risk for future stroke on the grade of carotid calcification. METHODS: Neuroradiologic findings in 187 patients who underwent CT and MR imaging examinations within 1 month of each other were retrospectively reviewed. The degree of circumferential calcification and thickness of calcification were graded for the cavernous carotid arteries on the basis of CT findings. Using the scale developed by the Cardiovascular Health Study, the white matter was graded for degree of disease on the basis of MR findings. Correlation tests and regression analyses were performed to determine the impact of age, race, and sex on results. RESULTS: Although the cavernous carotid calcification scores and the MR imaging white matter scores showed good correlation (P <.001), the effect was mediated by age. With age factored in as a covariant, no correlation was shown between CT calcification scores and MR imaging white matter scores. Sex had no effect, but African American study participants had worse MR imaging white matter scores than did white participants. CONCLUSION: After adjusting for age, cavernous carotid calcification grades and MR imaging white matter scores do not show a significant correlation. The relative risk for future stroke cannot be predicted from cavernous carotid calcifications.

Adult↗
PubMed2002

Diffuse axonal injuries: pathophysiology and imaging.

Diffuse axonal shear injury is a common traumatic brain injury, with significant neurologic and behavioral impact on patients. Radiologic recognition of this entity and understanding of its sequelae can be of utmost importance in the prediction of outcome and planning for rehabilitation. MRI has proven to be the optimal means of detection and characterization of DAI lesions, with GRE and FLAIR sequences being particularly helpful, and more advanced techniques such as MRS show preliminary evidence of some utility in determining outcome.

Brain↗
PubMed2002

Carotid artery atherosclerosis: in vivo morphologic characterization with gadolinium-enhanced double-oblique MR imaging initial results.

In nine subjects with carotid atherosclerosis, double-oblique, contrast material-enhanced, double inversion-recovery, fast spin-echo magnetic resonance (MR) images were acquired through atheroma in the proximal internal carotid artery. Fibrocellular tissue within atheroma selectively enhanced 29% after administration of gadolinium-based contrast agent. Contrast enhancement helped discriminate fibrous cap from lipid core with a contrast-to-noise ratio as good as or better than that with T2-weighted MR images but with approximately twice the signal-to-noise ratio (postcontrast images, 36.6 +/- 3.6; T2-weighted images, 17.5 +/- 2.1; P <.001).

Aged↗
PubMed2002

Bilateral arch origin of the vertebral arteries.

A case of bilateral anomalous origins of the vertebral arteries (VAs) is reported. Both VAs arose directly from the aortic arch between the left common carotid artery and the left subclavian artery. The possible embryologic mechanism and clinical importance of this previously unreported variant are reviewed.

Angiography, Digital Subtraction↗
PubMed2002

Intracranial hypotension as a cause of radiculopathy from cervical epidural venous engorgement: case report.

We describe the case of a 40-year-old man with spontaneous intracranial hypotension who presented with cervical radiculopathy associated with epidural venous engorgement. Epidural venous engorgement can occur secondary to intracranial hypotension and manifests intracranially as pachymeningeal venous engorgement. In the cervical spine, two cases of epidural venous engorgement due to intracranial hypotension have been reported in the literature, and neither patient presented with symptoms related to nerve compression. Epidural venous engorgement should be considered in the differential diagnosis of an enhancing epidural mass in the cervical spine. Diagnostic clues include sparing of the anterior midline and posterior aspects of the epidural space and, if present, pulsation artifact.

Adult↗
PubMed2002

Serial MR Imaging of Annular Tears in Lumbar Intervertebral Disks.

BACKGROUND AND PURPOSE: Annular tears of lumbar intervertebral disks are found in both symptomatic and asymptomatic persons; therefore, it is difficult to determine whether these findings indicate acute abnormality. Our purpose was to determine whether the MR imaging findings of tears (ie, hyperintensity and contrast enhancement) of the annulus fibrosus persist or resolve over time. METHODS: A radiologic database was searched for spinal MR imaging examinations noting annular tears. Eighteen patients were identified who had undergone more than one spinal MR imaging study. The images were reviewed for presence or absence of annular tears, defined as an area of hyperintensity on T2-weighted images or enhancement in the posterior annulus, separate from the nucleus pulposus. RESULTS: Annular tears were observed at 29 levels in 18 patients. Two tears developed during the follow-up interval. When contrast-enhanced images were obtained during serial examinations, 10 (100%) of 10 enhancing annular tears persisted on the follow-up contrast-enhanced T1-weighted images (mean interval, 17.2 months; SD, 12.3 months). High signal intensity on T2-weighted MR images was noted in 26 (96%) of 27 tears initially and persisted in 23 (88%) of 26 (mean interval, 21.9 months; SD, 15.0 months). CONCLUSION: Hyperintensity on T2-weighted MR images and enhancement of annular tears could not be used to determine the tears' acuity over the range of follow-up provided in this study.

Adult↗
PubMedDate not supplied

Magnetic resonance imaging of the pediatric spine.

Magnetic resonance is an excellent modality for imaging the pediatric spine. Its successful use requires understanding both the basic physics and the sedation protocols necessary for acquiring high-resolution images. Interpreting the images accurately depends on appreciating the differences between the normal anatomy of the pediatric and the adult spine. Evaluating the images requires familiarity with the differential diagnosis of pediatric spine disease, including the most common processes (infections, neoplasms, and trauma) as well as spinal dysraphism. Despite the acknowledged usefulness of magnetic resonance imaging of the pediatric spine, controversies remain related to its safety in this age group and its limitations in diagnosing and evaluating scoliosis and tethered cord syndrome.

Adolescent↗
PubMedDate not supplied

Middle cerebral artery infarction: relationship of cavernous carotid artery calcification.

BACKGROUND AND PURPOSE: This study was designed to determine whether calcification of the cavernous carotid artery (CCA) is associated with cerebrovascular infarcts in the same way that coronary artery calcification scores indicate myocardial infarctions. We sought to correlate the grade of CCA calcification with infarctions in the middle cerebral artery (MCA) distribution. METHODS: Nonenhanced brain CT scans of 40 patients with MCA-distribution strokes, 34 with non-MCA-distribution strokes, and 94 age-matched control subjects were reviewed. Circumferential calcification and thickness of calcification were graded for the CCAs on head CT scans. Scores were determined for the left and right CCAs. Mann-Whitney tests and Spearman correlation coefficients were used to detect differences between patients and control subjects and between patients with MCA and those with non-MCA strokes. RESULTS: CCA calcification scores did not significantly differ in the groups compared. The manner in which calcification was scored (by using circumference, thickness, or both) did not affect the results. No difference was noted between scores ipsilateral and those contralateral to the stroke. CONCLUSION: Circumferential degree or thickness of cavernous artery calcification was not correlated with MCA or non-MCA infarctions. CCA calcification scores did not differ between patients with stroke and those without stroke.

Adult↗