Andrew D. Schweitzer

Carotid Plaque MRI and Stroke Risk A Systematic Review and Meta-analysis

Background and Purpose— MRI characterization of carotid plaque has been studied recently as a potential tool to predict stroke caused by carotid atherosclerosis. We performed a systematic review and meta-analysis to summarize the association of MRI-determined intraplaque hemorrhage, lipid-rich necrotic core, and thinning/rupture of the fibrous cap with subsequent ischemic events. Methods— We performed a comprehensive literature search evaluating the association of carotid plaque composition on MRI with ischemic outcomes. We included cohort studies examining intraplaque hemorrhage, lipid-rich necrotic core, or thinning/rupture of the fibrous cap with mean follow-up of ≥1 month and an outcome measure of ipsilateral stroke or transient ischemic attack. A meta-analysis using a random-effects model with assessment of study heterogeneity and publication bias was performed. Results— Of the 3436 articles screened, 9 studies with a total of 779 subjects met eligibility for systematic review. The hazard ratios for intraplaque hemorrhage, lipid-rich necrotic core, and thinning/rupture of the fibrous cap as predictors of subsequent stroke/transient ischemic attack were 4.59 (95% confidence interval, 2.91–7.24), 3.00 (95% confidence interval, 1.51–5.95), and 5.93 (95% confidence interval, 2.65–13.20), respectively. No statistically significant heterogeneity or publication bias was present in the 3 main meta-analyses performed. Conclusions— The presence of intraplaque hemorrhage, lipid-rich necrotic core, and thinning/rupture of the fibrous cap on MRI of carotid plaque is associated with increased risk of future stroke or transient ischemic attack in patients with carotid atherosclerotic disease. Dedicated MRI of plaque composition offers stroke risk information beyond measurement of luminal stenosis in carotid atherosclerotic disease.

Improved Subthalamic Nucleus Depiction with Quantitative Susceptibility Mapping

PURPOSE To assess quantitative susceptibility mapping (QSM) in the depiction of the subthalamic nucleus (STN) by using 3-T magnetic resonance (MR) imaging. MATERIALS AND METHODS This study was HIPAA compliant and institutional review board approved. Ten healthy subjects (five men, five women; mean age, 24 years ± 3 [standard deviation]; age range, 21-33 years) and eight patients with Parkinson disease (five men, three women; mean age, 57 years ± 14; age range, 25-69 years) who were referred by neurologists for preoperative navigation MR imaging prior to deep brain stimulator placement were included in this study. T2-weighted (T2w), T2*-weighted (T2*w), R2* mapping (R2*), phase, susceptibility-weighted (SW), and QSM images were reconstructed for STN depiction. Qualitative visualization scores of STN and internal globus pallidus (GPi) were recorded by two neuroradiologists on all images. Contrast-to-noise ratios (CNRs) of the STN and GPi were also measured. Measurement differences were assessed by using the Wilcoxon rank sum test and the signed rank test. RESULTS Qualitative scores were significantly higher on QSM images than on T2w, T2*w, R2*, phase, or SW images (P < .05) for STN and GPi visualization. Median CNR was 6.4 and 10.7 times higher on QSM images than on T2w images for differentiation of STN from the zona incerta and substantia nigra, respectively, and was 22.7 and 9.1 times higher on QSM images than on T2w images for differentiation of GPi from the internal capsule and external globus pallidus, respectively. CNR differences between QSM images and all other images were significant (P < .01). CONCLUSION QSM at 3-T MR imaging performs significantly better than current standard-of-care sequences in the depiction of the STN.

Quantitative Susceptibility Mapping of the Motor Cortex in Amyotrophic Lateral Sclerosis and Primary Lateral Sclerosis

OBJECTIVE The diagnosis of amyotrophic lateral sclerosis (ALS) and primary lateral sclerosis (PLS) is often difficult because of a lack of disease biomarkers. The purpose of this study was to investigate quantitative susceptibility mapping (QSM) of the motor cortex as a potential quantitative biomarker for the diagnosis of ALS and PLS. MATERIALS AND METHODS From a retrospective database, QSM images of 16 patients with upper motor neuron disease (nine men [56%], seven women; mean age, 56.3 years; 12 with ALS, four with PLS) and 23 control patients (13 men [56%], 10 women; mean age, 56.6 years) were reviewed. Two neuroradiologists, blinded to diagnosis, qualitatively assessed QSM, T2- and T2*-weighted, and T2-weighted FLAIR images. Relative motor cortex susceptibility was calculated by subtraction of adjacent white matter and CSF signal intensity from mean motor cortex susceptibility on the axial image most representative of the right- or left-hand lobule, and ROC analysis was performed. The Fisher exact and Student t tests were used to evaluate for statistical differences between the groups. RESULTS Qualitatively, QSM had greater diagnostic accuracy than T2-weighted, T2*-weighted, or T2-weighted FLAIR imaging for the diagnosis of ALS and PLS. Quantitatively, relative motor cortex susceptibility was found to be significantly greater in patients with motor neuron disease than in control patients (46.0 and 35.0 ppb; p < 0.001). ROC analysis showed an AUC of 0.88 (p < 0.0001) and an optimal cutoff value of 40.5 ppb for differentiating control patients from patients with ALS or PLS (sensitivity, 87.5%; specificity, 87.0%). CONCLUSION QSM is a sensitive and specific quantitative biomarker of iron deposition in the motor cortex in ALS and PLS.

The imaging spectrum of posterior reversible encephalopathy syndrome: A pictorial review

Posterior reversible encephalopathy syndrome (PRES) is characterized by the acute onset of neurologic symptoms (headache, altered mental status, visual changes, seizures) with accompanying vasogenic edema on brain imaging. Risk factors for PRES include infection, uremia, malignancy, autoimmune disorders, the peripartum state and hypertension. PRES is classically described as being posterior (i.e. parieto-occipital) but radiologic variants are increasingly recognized. This pictorial review demonstrates the heterogeneity of the different radiologic presentations of PRES in reference to lesion distribution, hemorrhage, diffusion restriction, contrast enhancement, and other associated findings.

Glioblastoma-arteriovenous fistula complex: imaging characteristics and treatment considerations

Although a certain degree of arteriovenous shunting may be expected in glioblastoma, to our knowledge, the coexistence of a glioblastoma and arteriovenous fistula has not been previously reported. In this case report, we present such a lesion and discuss its diagnosis with a multimodal imaging approach. Additionally, we discuss treatment considerations for such a lesion.

Percutaneous CT-guided facet joint synovial cyst rupture: Success with refractory cases and technical considerations

Percutaneous image-guided rupture of lumbar facet synovial cysts can improve clinical outcomes and obviate the need for open surgery. This series describes eleven patients who had successful CT-guided lumbar facet synovial cyst ruptures, 82% of which experienced excellent pain relief at a minimum of one-year follow-up. Of the five patients who failed prior fluoroscopic-guided synovial cyst rupture, 80% had a successful CT-guided rupture and one-year sustained pain relief. These findings reinforce minimally invasive CT-guided treatment as an excellent option to improve patient symptoms and potentially avoid open surgery.

Corticosteroid therapy and severity of vasogenic edema in posterior reversible encephalopathy syndrome.

BACKGROUND Posterior reversible encephalopathy syndrome (PRES) is a variable cerebrovascular syndrome associated with hypertension and autoregulatory failure. Steroids have been reported to both precipitate and treat PRES. We sought to determine the prevalence of steroid therapy at the time of PRES and to assess the relationship between steroid therapy and extent of vasogenic edema. METHODS We performed a retrospective review of radiology reports between 2008 and 2014 from two academic medical centers to identify cases of PRES. Clinical and radiographic data were collected. Descriptive statistics were used to determine the prevalence of corticosteroid therapy at the time of PRES onset and the latency from steroid initiation to PRES onset. The association between steroid therapy and extent of vasogenic edema was assessed in multiple regression models. RESULTS We identified 99 cases of PRES in 96 patients. The median age was 55years (IQR 30-65) and 74% were women. Steroid therapy at time of PRES onset was identified in 44 of 99 cases. Excluding patients on chronic therapy, the median duration of steroid exposure before PRES onset was 6 (IQR, 3-10) days. Steroid therapy was not associated with extent of vasogenic edema in unadjusted or linear and logistic regression models adjusted for age, sex, and maximum systolic blood pressure on day of onset. CONCLUSION Corticosteroid therapy, often of brief duration, frequently preceded the onset of PRES and was not associated with severity of vasogenic edema.

CT-guided epidural blood patch for treatment of CSF leak and pseudomeningocele following tethered cord release in a 3-year-old

An epidural blood patch (EBP) has become standard of care for management of postdural puncture headache, and in recent years, attempts have been made to expand its applicability. Its utility in the management of postsurgical pseudomeningocele remains poorly defined, and few reports describe its use in children. In this case, we report the successful management of lumbar pseudomeningocele via EBP in a 3-year-old after tethered cord release, thereby obviating the need for surgical repair and its potential morbidity.

Imaging of Plexopathy in Oncologic Patients

Abstract Often complementary to clinical assessment, imaging of the brachial and lumbosacral plexus can be used to characterize plexus involvement by primary neoplasm, metastases, or conditions related to treatment. The imaging modality of choice, magnetic resonance (MR) without and with contrast, typically includes T1-weighted and fat-suppressed T2-weighted images. MR can delineate primary plexus neoplasms, including benign and malignant peripheral nerve sheath tumors, and accurately characterizes the extent of plexus involvement due to infiltrative malignancy. In cases in which there is clinical uncertainty between recurrent tumor and radiation injury, MR has been shown to be highly sensitive and specific. Positron emission tomography/computed tomography has also been shown to be useful in excluding recurrent tumor. MR imaging techniques that have been more recently investigated in plexus imaging, including diffusion-weighted imaging, isotropic three-dimensional imaging, diffusion tensor imaging, and fiber tractography, show potential to further complement clinical evaluation.

Imaging findings of spinal brown tumors: a rare but important cause of pathologic fracture and spinal cord compression

Brown tumors rarely develop in the spine, and neurological compromise is exceedingly uncommon. There is a growing body of literature describing brown tumors that involve the spine, but few emphasize the radiographic findings. In the present case, we illustrate the development and progression of biopsy-proven brown tumors leading to neurological compromise through radiographs, computed tomography, magnetic resonance, and nuclear imaging acquired over a 4-year span.