Glenn D. Barest

Impact of MDCT angiography on the use of catheter angiography for the assessment of cervical arterial injury after blunt or penetrating trauma.

OBJECTIVE The objective of our study was to assess the impact of the increasing use of MDCT angiography in the setting of blunt and penetrating neck trauma on the use of digital subtraction angiography (DSA) at our institution, a level 1 trauma center. MATERIALS AND METHODS From January 2001 to December 2003, 57 patients were referred for CT angiography or DSA of the neck after blunt or penetrating neck trauma. All CT angiograms were acquired with a 4-MDCT scanner. The patients were divided into three groups on the basis of consecutive 12-month periods (2001, 2002, and 2003), and the initial imaging technique was recorded. The results of CT and digital subtraction angiograms were compared with operative findings and with clinical course, when available. RESULTS In 2001, 12 patients were referred for imaging: nine patients were evaluated initially with DSA and three patients were evaluated with CT angiography and subsequently with DSA. In 2002 and 2003, 11 and 34 patients, respectively, underwent CT angiography as the initial imaging examination. During these 2 years, no patient underwent DSA as the initial diagnostic test, but five patients underwent DSA after CT angiography for the following indications: evaluation of nondiagnostic CT angiograms (n = 1), confirmation of findings when requested by the clinical service (n = 2), and catheter-guided therapy (n = 2). CONCLUSION CT angiography has essentially replaced DSA as the study of choice for the initial evaluation of the neck vessels in the setting of blunt or penetrating trauma at our institution. CT angiography is adequate for the initial evaluation, allows appropriate triage of patients to conventional angiography or surgery for appropriate treatment, and can guide conservative management when appropriate.

Diffusion‐Weighted Imaging of Cerebral Malaria

Cerebral malaria occurs in 2% of patients infected by Plasmodium falciparum. Magnetic resonance imaging findings of small white matter infarcts due to cerebral malaria have been previously reported, however nonspecific. Since diffusion‐weighted imaging can differentiate acute embolic infarcts from other chronic or nonspecific white matter lesions, it may aid diagnosis of this illness in patients who travel to endemic areas.

The intravertebral distribution of bone density: correspondence to intervertebral disc health and implications for vertebral strength

SummaryThis studys goal was to determine associations among the intravertebral heterogeneity in bone density, bone strength, and intervertebral disc (IVD) health. Results indicated that predictions of vertebral strength can benefit from considering the magnitude of the density heterogeneity and the congruence between the spatial distribution of density and IVD health.IntroductionThis study aims to determine associations among the intravertebral heterogeneity in bone density, bone strength, and IVD healthMethodsRegional measurements of bone density were performed throughout 30 L1 vertebral bodies using micro-computed tomography (μCT) and quantitative computed tomography (QCT). The magnitude of the intravertebral heterogeneity in density was defined as the interquartile range and quartile coefficient of variation in regional densities. The spatial distribution of density was quantified using ratios of regional densities representing different anatomical zones (e.g., anterior to posterior regional densities). Cluster analysis was used to identify groups of vertebrae with similar spatial distributions of density. Vertebral strength was measured in compression. IVD health was assessed using two scoring systems.ResultsQCT- and μCT-based measures of the magnitude of the intravertebral heterogeneity in density were strongly correlated with each other (p < 0.005). Accounting for the interquartile range in regional densities improved predictions of vertebral strength as compared to predictions based only on mean density (R2 = 0.59 vs. 0.43; F-test p-value = 0.018). Specifically, after adjustment for mean density, vertebral bodies with greater heterogeneity in density exhibited higher strength. No single spatial distribution of density was associated with high vertebral strength. Analyses of IVD scores suggested that the health of the adjacent IVDs may modulate the effect of a particular spatial distribution of density on vertebral strength.ConclusionsNoninvasive measurements of the intravertebral distribution of bone density, in conjunction with assessments of IVD health, can aid in predictions of bone strength and in elucidating biomechanical mechanisms of vertebral fracture.

Approach to imaging the patient with neck pain.

Neck pain is a common complaint of patients seeking care in the outpatient setting, and the cases seen vary widely in severity and cause. A careful history and physical exam, followed by appropriate imaging studies, are essential for the orderly workup and management of neck pain in the ambulatory patient. Available imaging studies include plain film radiography, computed tomography (CT), magnetic resonance, and CT myelography. The general considerations necessary to select the appropriate imaging study are discussed for a broad spectrum of common disorders.

Duplication of the Posterior Cerebral Artery and the ‘True Fetal' Variant

We present a rare case of bilateral posterior cerebral artery variant anatomy seen in a patient presenting with acute ischemic stroke. An embryological explanation of the variant configuration is discussed along with demonstrative radiologic images and a display of the vascular territory supplied.

“Dazed and diffused”: making sense of diffusion abnormalities in neurologic pathologies

To review diffusion abnormalities seen in diffusion-weighted MRI in neurological pathologies. We examine the clinical significance of the abnormalities in a broad spectrum of neurological diseases and highlight our current understanding of their causes. Diffusion abnormalities seen on diffusion-weighted MRI can play an important role in the diagnosis and follow-up of a broad spectrum of neurological diseases. A thorough understanding of the appearance and significance of these abnormalities is critical in patient management.

Spontaneous Resolution of Post-Traumatic Direct Carotid-Cavernous Fistula

Post-traumatic carotid-cavernous fistulas are due to a tear in the wall of the cavernous carotid artery, leading to shunting of blood into the cavernous sinus. These are generally high-flow fistula and rarely resolve spontaneously. Most cases require endovascular embolization. We report a case of Barrow type A carotid-cavernous fistula which resolved spontaneously.

Is bone density associated with intervertebral disc pressure in healthy and degenerated discs

The coupling of the intervertebral disc (IVD) and vertebra as a biomechanical unit suggests that changes in the distribution of pressure within the IVD (intradiscal pressure, IDP) as a result of disc degeneration can influence the distribution of bone density within the vertebra, and vice versa. The goal of this study was to assess the correspondence between IDP and bone density in the adjacent vertebrae, with emphasis on how this correspondence differs between healthy and degenerated IVDs. Bone density of the endplates and subchondral bone in regions adjacent to the anterior and posterior annulus fibrosus (aAF and pAF, respectively) and nucleus pulposus (NP) was measured via quantitative computed tomography (QCT) in 61 spine segments (T7-9, T9-11, T10-12; 71±14years). IDP was measured in the aAF, NP, and pAF regions in 26 of the spine segments (68±16years) while they were tested in flexed (5°) or erect postures. Disc degeneration was assessed by multiple grading schemes. No correlation was found between bone density and IDP in either posture (p>0.104). Regional variations in IDP and, to a greater extent bone density, were found to change with advancing degeneration: both IDP (p=0.045) and bone density (p=0.024) decreased in the NP region relative to the aAF region. The finding of only a modest correspondence between degeneration-associated changes in IDP and bone density may arise from complexity in how IDP relates to mechanical force transmission through the endplate and from limitations of the available IVD grading schemes in estimating the mechanical behavior of the IVD.

Influence of Specimen-Specific Trabecular Anisotropy on QCT-Based Finite Element Analyses of Lumbar Vertebra

Quantitative computed tomography (QCT)-based finite element (FE) models provide better predictions of vertebral strength compared to traditional methods currently used in clinical diagnosis [1]. In QCT-based FE models, the intra- and inter-specimen variations in trabecular anisotropy are often ignored, despite evidence that the biomechanical behavior of the vertebra depends on the architecture of the vertebral trabecular bone [2]. A realistic representation of the specimen-specific, trabecular anisotropy in the FE models of vertebrae would potentially improve predictions of vertebral failure. The overall goal of this study was to evaluate the importance of incorporating specimen-specific, trabecular anisotropy for QCT-based FE predictions of vertebral stiffness and deformation patterns. The major aims of this study were (a) to compare the QCT-based FE results obtained with a constant, anisotropic, material model (the “generic-anisotropic” model) for trabecular bone to those obtained with a specimen-specific, anisotropic, material model and (b) to study the influence of degree of anisotropy (DA) on the FE predictions of vertebral stiffness.Copyright