Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Aug 2013
Case ReportsNeuropathological correlate of the "concentric target sign" in MRI of HIV-associated cerebral toxoplasmosis.
Cerebral toxoplasmosis is a frequent cause of focal brain lesions in the setting of immunodeficiency states, particularly acquired immune deficiency syndrome (AIDS), and magnetic resonance imaging (MRI) is an important diagnostic modality to differentiate toxoplasmosis from tuberculoma, and primary central nervous system lymphoma with diverse therapeutic implications. Several imaging patterns have been described in cerebral toxoplasmosis. The "concentric target sign" is a recently described MRI sign on T2-weighted imaging of cerebral toxoplasmosis that has concentric alternating zones of hypo- and hyperintensities. ⋯ In this study we describe the neuropathological correlate of this concentric target sign from the postmortem of a 40-year-old man with AIDS-associated cerebral toxoplasmosis. The concentric alternating zones of hypo/hyper/iso/intensities corresponded to zones of hemorrhage/fibrin-rich necrosis with edema/coagulative compact necrosis/inflammation with foamy histiocytes admixed with hemorrhage forming the outermost zone, respectively. The exclusive specificity of this sign in cerebral toxoplasmosis remains to be further elucidated.
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J Magn Reson Imaging · Aug 2013
Comparative StudyLiver T2-weighted MR imaging: assessment of a three-dimensional fast spin-echo with extended echo train acquisition sequence at 1.5 Tesla.
To retrospectively compare image quality and lesion detectability with two T2-weighted sequences at 1.5 Tesla (T): respiratory-triggered three-dimensional fat sat fast-spin-echo with extended echo-train acquisition (3D FSE-XETA) and respiratory-triggered two-dimensional fat-sat fast recovery fast-spin-echo (2D FRFSE). ⋯ For T2-weighted liver imaging at 1.5T, the 3D FSE-XETA sequence improves sensitivity, reader confidence score and interobserver correlation for focal liver lesion detection, but it suffers from a lower overall image quality and higher artifacts.
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J Magn Reson Imaging · Aug 2013
T1ρ mapping of pediatric epiphyseal and articular cartilage in the knee.
To evaluate the feasibility of measuring T1ρ values in epiphyseal cartilage in children, we have conducted a novel study of spin locking techniques. Adult articular cartilage has been widely studied with spin locking techniques by magnetic resonance imaging. However, no results are available for in vivo T1ρ imaging of developing cartilage. ⋯ It is feasible to quantify differences in epiphyseal and articular cartilage layers with SL techniques. T1ρ holds promise as a noninvasive method of studying normal and abnormal developmental states of cartilage in children.
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J Magn Reson Imaging · Aug 2013
Case ReportsSuperselective arterial spin labeling applied for flow territory mapping in various cerebrovascular diseases.
In three example patients suffering from internal carotid artery occlusion, intracranial steno-occlusive disease, and symptomatic arteriovenous malformation (AVM), a new method named superselective pseudo-continuous arterial spin labeling (pCASL) was used in addition to clinical routine measurements. The capabilities of this method are demonstrated to gain important information in diagnosis, risk analysis, and treatment monitoring that are neither accessible by digital subtraction angiography nor by existing selective arterial spin labeling methods and thus to propose future applications in clinical routine. In all cases superselective pCASL enabled the assessment of tissue viability and of territorial brain perfusion at different levels starting from major brain feeding vessels to collateral circulation at the level of the Circle of Willis to even distal branching arteries. This made it possible to estimate the contribution of an extracranial-intracranial bypass to the brain perfusion; to depict individual arteries to important functional brain areas; to identify en-passant feeding vessels of an AVM and to track possible changes in their perfusion territories after intervention.
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J Magn Reson Imaging · Aug 2013
Reproducibility of brain spectroscopy at 7T using conventional localization and spectral editing techniques.
To evaluate the reproducibility of spectroscopic measurements from the anterior cingulate (AC) and the dorsolateral prefrontal cortex (DLPFC) regions at 7T using a 32-channel head coil. ⋯ 7T MR spectroscopy of the AC and DLPFC using both short TE STEAM and MEGA-PRESS-IVS sequences provide excellent reproducibility of 12 metabolites, including GABA.