Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Review
Application of chemical exchange saturation transfer (CEST) MRI for endogenous contrast at 7 Tesla.
Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) indirectly images exchangeable solute protons resonating at frequencies different than bulk water. These solute protons are selectively saturated using low bandwidth RF irradiation and saturation is transferred to bulk water protons via chemical exchange, resulting in an attenuation of the measured water proton signal. CEST MRI is an advanced MRI technique with wide application potential due to the ability to examine complex molecular contributions. ⋯ Increased field strength translates to enhanced quantification of the metabolite of interest, allowing more fundamental studies on underlying pathophysiology. CEST contrast is affected by several tissue properties, such as the concentrations of exchange partners and their rate of proton exchange, whose effects have been examined and explored in this review. We have highlighted the background of CEST MRI, typical implementation strategy, and complications at 7 T.
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The Cavum Septi Pellucidi (CSP), Cavum Vergae (CV) and Cavum Veli Interpositi, are anatomical variants located in the midline of the brain. It is important to identify these conditions to distinguish them from other entities that may require treatment. In this paper, our purpose is to describe MR and CT findings of CSP, CV and Cavum Veli Interpositi, explaining the differential diagnosis.
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Review Case Reports
Cavernous carotid pseudoaneurysm following transsphenoidal surgery.
Pseudoaneurysm of the internal carotid artery (ICA) as a result of injury during transsphenoidal surgery is a rare but serious complication. We present a review of this subject, identifying 22 such cases in the literature, and contribute an unusual case of our own. Among our cohort, 23% of patients had no evidence of vascular injury or hemorrhage during the initial transsphenoidal operation, and presented at an average of 83 days after surgery. ⋯ Though complete occlusion of the ICA was ultimately required in 41% of patients, the remainder were treated with a variety of modalities. While intraoperative hemorrhage is certainly the most predictive indicator of iatrogenic vascular damage, in its absence, other signs such as postoperative bruits may be predictive of pseudoaneurysm formation as well. The continued accumulation of these unique cases will hopefully provide definitive recommendations on the early recognition and treatment of this serious condition, especially regarding the emerging role of endovascular therapy in its management.
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Time window for thrombolysis in acute ischemic stroke can be based on chronological or physiological (imaging) data. Both of these approaches have their unique strengths and weaknesses. ⋯ Therefore, careful evaluation of strategies using image-based identification of patients who might benefit from thrombolysis is needed. Patients undergoing thrombolysis on delayed arrival appear to be the most logical group in whom image-based strategies should be evaluated.
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Diagnosis of tibial neuropathy has been traditionally based on clinical examination and electrodiagnostic studies; however, cross-sectional imaging modalities have been used to increase the diagnostic accuracy and provide anatomic mapping of the abnormalities. In this context, magnetic resonance neurography (MRN) offers high-resolution imaging of the tibial nerve (TN), its branches and the adjacent soft tissues, and provides an objective assessment of the neuromuscular anatomy, abnormality, and the surrounding pathology. This review describes the pathologies affecting the TN and illustrates their respective 3 Tesla (T) MRN appearances with relevant case examples.