Category Archives: Editor’s Choices

Arterial Spin-Labeling Parameters Influence Signal Variability and Estimated Regional Relative Cerebral Blood Flow in Normal Aging and Mild Cognitive Impairment: FAIR versus PICORE Techniques

Editor’s Choice Editor’s Comments

In healthy controls and 43 patients with mild cognitive impairment, 2 pulsed ASL sequences were performed at 3T: proximal inversion with a control for off-resonance effects (PICORE) and the flow-sensitive alternating inversion recovery technique (FAIR). FAIR had higher estimated relative CBF and lower interindividual variability than PICORE.

Abstract

The average rCBF for FAIR, PICORE, and the difference between both ASL sequences.

BACKGROUND AND PURPOSE

Arterial spin-labeling is a noninvasive method to map cerebral blood flow, which might be useful for early diagnosis of neurodegenerative diseases. We directly compared 2 arterial spin-labeling techniques in healthy elderly controls and individuals with mild cognitive impairment.

MATERIALS AND METHODS

This prospective study was approved by the local ethics committee and included 198 consecutive healthy controls (mean age, 73.65 ± 4.02 years) and 43 subjects with mild cognitive impairment (mean age, 73.38 ± 5.85 years). Two pulsed arterial spin-labeling sequences were performed at 3T: proximal inversion with a control for off-resonance effects (PICORE) and flow-sensitive alternating inversion recovery technique (FAIR). Relative cerebral blood flow maps were calculated by using commercial software and standard parameters. Data analysis included spatial normalization of gray matter–corrected relative CBF maps, whole-brain average, and voxelwise comparison of both arterial spin-labeling sequences.

RESULTS

Overall, FAIR yielded higher relative CBF values compared with PICORE (controls, 32.7 ± 7.1 versus 30.0 ± 13.1 mL/min/100 g, P = .05; mild cognitive impairment, 29.8 ± 5.4 versus 26.2 ± 8.6 mL/min/100 g, P < .05; all, 32.2 ± 6.8 versus 29.3 ± 12.3 mL/min/100 g, P < .05). FAIR had lower variability (controls, 36.2% versus 68.8%, P < .00001; mild cognitive impairment, 18.9% versus 22.9%, P < .0001; all, 34.4% versus 64.9% P < .00001). The detailed voxelwise analysis revealed a higher signal for FAIR, notably in both convexities, while PICORE had … Continue reading >>

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Editor’s Choices from June 2015

Hart BL, Ketai L. Armies of Pestilence: CNS Infections as Potential Weapons of Mass Destruction. http://www.ajnr.org/content/36/6/1018.full

The imaging findings of CNS infection agents that may be used by governments and terrorist groups are presented. Viruses and anthrax are highly infectious and effective biowarfare weapons but bacteria also fulfill these requirements.

Asdaghi N, Coulter JI, Modi J, et al. Statin Therapy Does Not Affect the Radiographic and Clinical Profile of Patients with TIA and Minor Stroke. http://www.ajnr.org/content/36/6/1076.full

Imaging and clinical outcomes of high-risk patients with TIA and stroke who underwent acute statin treatment were assessed. These patients tended to be older, male, hypertensive, and have more atherosclerotic disease than those who did not receive statins. Early statin therapy was not associated with a reduction of DWI-positive lesions, infarct volume, or functional outcome at 3 months.

Shams S, Martola J, Cavallin L, et al. SWI or T2*: Which MRI Sequence to Use in the Detection of Cerebral Microbleeds? The Karolinska Imaging Dementia Study. http://www.ajnr.org/content/36/6/1089.full

The prevalence of cerebral microbleeds was evaluated in 246 patients using T2* and SWI. Microbleeds were detected in 21% by SWI vs. 17% by T2* imaging. SWI performed well with both thin and thick sections. Thus, SWI is better than T2* for this purpose and robust enough to permit comparison across studies.… Continue reading >>

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Editor’s Choices for May 2015

Krings T, Kim H, Power S, et al. Neurovascular Manifestations in Hereditary Hemorrhagic Telangiectasia: Imaging Features and Genotype-Phenotype Correlations. http://www.ajnr.org/content/36/5/863.full

Imaging features were correlated with genotypes in 75 patients with hereditary hemorrhagic telangiectasia. Sixty-one percent of patients showed small, superficial, capillary malformations without shunting, whereas 43% had true AVMs of small size and low Spetzler-Martin grade. High-flow AVFs were present in 12% of patients and multiple malformations were seen in 44%. No correlation between gene mutations and lesion types was found.

Golden MJ, Morrison LA, Kim H, et al. Increased Number of White Matter Lesions in Patients with Familial Cerebral Cavernous Malformations. http://www.ajnr.org/content/36/5/899.full

Because endothelial cell abnormalities are found in white matter hyperintensities and cavernous malformations, the authors set out to determine if an increased number of white matter lesions was present in 191 patients with familial cerebral cavernous malformations all carrying the same gene defect. Results were compared with those obtained via logistic regression analysis in healthy controls and patients with sporadic cavernous malformations. White matter lesions were found in 15% of patients with the familial disease, 2% of healthy controls, and 2.5% of those with sporadic malformations. In patients with the familial disease, only age was associated with white matter lesions.

Cho CH, Hsu L, Ferrone ML, et al. Validation of Multisociety Combined Task Force Definitions of Abnormal Disk Morphology. http://www.ajnr.org/content/36/5/1008.full

Fifty-four patients underwent classification of lumbar disk herniations during preoperative MRI and surgery using the new multisociety classification. Disagreement as to classification based on MRI studies occurred in only 1 instance and agreement of preoperative classification with operative findings was 70%. The authors believe that though this level of agreement is reasonable, differences exist between what neuroradiologists see on imaging and what surgeons encounter.… Continue reading >>

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Editor’s Choices for April 2015

van der Kolk AG, Zwanenburg JJM, Denswil NP, et al. Imaging the Intracranial Atherosclerotic Vessel Wall Using 7T MRI: Initial Comparison with Histopathology. http://www.ajnr.org/content/36/4/694.full

In this preliminary study, 7T imaging was capable of identifying not only intracranial wall thickening but different plaque components such as foamy macrophages and collagen. Signal heterogeneity was typical of advanced atherosclerotic disease.

Ohta T, Nakahara I, Ishibashi R, et al. The Maze-Making and Solving Technique for Coil Embolization of Large and Giant Aneurysms. http://www.ajnr.org/content/36/4/744.full

These authors describe the use of 2 intra-aneurysmal catheters to deploy first large coils and then smaller, more traditional coils that ultimately fill the interstices left by the larger coils until aneurysms are tightly packed. When this technique was used to occlude large/giant aneurysms, follow-up angiography revealed no recurrences compared with nearly 40% in a group of similar lesions treated in conventional fashion.

Brinjikji W, Luetmer PH, Comstock B, et al. Systematic Literature Review of Imaging Features of Spinal Degeneration in Asymptomatic Populations. http://www.ajnr.org/content/36/4/811.full

This meta-analysis of the literature reveals that imaging findings of spine degeneration are present in high proportions of asymptomatic individuals, increasing with age. Many imaging-based degenerative features are likely part of normal aging and unassociated with pain.… Continue reading >>

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Percutaneous Injection of Radiopaque Gelified Ethanol for the Treatment of Lumbar and Cervical Intervertebral Disk Herniations: Experience and Clinical Outcome in 80 Patients

Editor’s Choice March 2015

(3 of 3)

Eighty lumbar and 9 cervical spine herniations were treated with percutaneous intradiskal injection of gelified ethanol under fluoroscopy with 36 injections made simultaneously for 2 disk herniations. Post treatment symptom improvement was reported by 85% of patients with lumbarand 83% of those with cervical disk herniations.

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Impact of Time-to-Reperfusion on Outcome in Patients with Poor Collaterals

Editor’s Choice March 2015

(2 of 3)

More than 200 patients with MCA +/- ICA occlusions who successfully reperfused with endovascular techniques were assessed. The probability of good outcome was not significantly influenced by onset-to-reperfusion and puncture-to-reperfusion periods in patients with good collaterals but dropped significantly in patients with poor collaterals.

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White Matter Correlates of Cognitive Impairment in Essential Tremor

Editor’s Choice March 2015

(1 of 3)

A series of 55 patients with essential tremor and an equal number of age-matched controls were assessed clinically and by DTI. Alterations in executive and visual spatial functions correlated with DTI measures suggesting an anatomic basis for cognitive impairment in these patients.

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Visual Outcomes with Flow-Diverter Stents Covering the Ophthalmic Artery for Treatment of Internal Carotid Artery Aneurysms

Editor’s Choice February 2015

(3 of 3)

Outcomes in 28 patients in whom a stent covered the origin of the ophthalmic artery were reviewed. In 86%, the artery remained patent but 40% showed clinical ophthalmic complications. Thus, a stent covering the origin of this artery is not without complications and should be avoided when possible.

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Do FLAIR Vascular Hyperintensities beyond the DWI Lesion Represent the Ischemic Penumbra?

Editor’s Choice February 2015

(2 of 3)

FLAIR images from over 140 patients with acute MCA infarctions were analyzed and compared with images used to estimate the ischemic penumbra. A FLAIR-DWI mismatch was seen in 72% of patients and the authors concluded that this may be used to identify the ischemic penumbra.

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Abstract

BACKGROUND AND PURPOSE
In acute stroke with proximal artery occlusion, FLAIR vascular hyperintensities observed beyond the boundaries of the cortical lesion on DWI (newly defined “FLAIR vascular hyperintensity–DWI mismatch”) may be a marker of tissue at risk of infarction. Our aim was to compare the occurrence of FLAIR vascular hyperintensity–DWI mismatch relative to that of perfusion-weighted imaging–DWI mismatch in patients with proximal MCA occlusion before IV thrombolysis.

MATERIALS AND METHODS
In 141 consecutive patients with proximal MCA occlusion, 2 independent observers analyzed FLAIR images for the presence of FLAIR vascular hyperintensity–DWI mismatch before IV thrombolysis. PWI-DWI mismatch was defined as Volumehypoperfusion > 1.8 × VolumeDWI, with Volumehypoperfusion > 6 seconds on time to maximum value of the residue function maps in the 94 patients with available PWI. The presence of FLAIR vascular hyperintensity–DWI mismatch, PWI-DWI mismatch, and infarct growth on 24-hour follow-up DWI was compared.

RESULTS
A FLAIR vascular hyperintensity–DWI mismatch was present in 102/141 (72%) patients, with an excellent interobserver reliability (κ = 0.91), and a PWI-DWI mismatch, in 61 of the 94 (65%) patients with available PWI. FLAIR vascular hyperintensity–DWI mismatch predicted PWI-DWI mismatch with a sensitivity of 92% (95% CI, 85%–99%) and a specificity of 64% (95% CI, 47%–80%). Patients with FLAIR vascular hyperintensity–DWI mismatch had smaller initial DWI lesion and larger infarct growth (P < .001) than patients without FLAIR vascular hyperintensity–DWI mismatch, even though their final infarcts remained smaller (P < .001).

CONCLUSIONS
Albeit being

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MRI Findings in Children with Acute Flaccid Paralysis and Cranial Nerve Dysfunction Occurring during the 2014 Enterovirus D68 Outbreak

Editor’s Choice February 2015

(1 of 3)

MRI findings in 11 patients with acute flaccid paralysis are described and most commonly included extensive spinal cord lesions affecting the gray matter, especially the anterior horns, ventral cauda equina, and cervical ventral nerve roots as well as the pontinetegmentum.

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Abstract

BACKGROUND AND PURPOSE
Enterovirus D68 was responsible for widespread outbreaks of respiratory illness throughout the United States in August and September 2014. During this time, several patients presented to our institution with acute flaccid paralysis and cranial nerve dysfunction. The purpose of this report is to describe the unique imaging findings of this neurologic syndrome occurring during an enterovirus D68 outbreak.

MATERIALS AND METHODS
Patients meeting a specific case definition of acute flaccid paralysis and/or cranial nerve dysfunction and presenting to our institution during the study period were included. All patients underwent routine MR imaging of the brain and/or spinal cord, including multiplanar T1, T2, and contrast-enhanced T1-weighted imaging.

RESULTS
Eleven patients met the inclusion criteria and underwent MR imaging of the brain and/or spinal cord. Nine patients presented with brain stem lesions, most commonly involving the pontine tegmentum, with bilateral facial nerve enhancement in 1 patient. Ten patients had longitudinally extensive spinal cord lesions; those imaged acutely demonstrated involvement of the entire central gray matter, and those imaged subacutely showed lesions restricted to the anterior horn cells. Ventral cauda equina nerve roots enhanced in 4 patients, and ventral cervical nerve roots enhanced in 3, both only in the subacute setting.

CONCLUSIONS
Patients presenting with acute flaccid paralysis and/or cranial nerve dysfunction during the recent enterovirus D68 outbreak demonstrate unique imaging findings characterized by brain stem and gray matter spinal cord lesions, similar to the neuroimaging findings described in previous outbreaks of viral myelitis such as enterovirus 71 and poliomyelitis.

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