J Radiol
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Review Comparative Study
[Innovations in functional MR imaging of the brain: arterial spin labeling and diffusion].
The standard technique for brain activation functional MRI (fMRI) is the BOLD sequence. Two new techniques have emerged: arterial spin labeling (ASL) MRI and diffusion MRI. Both have the theoretical advantage of more accurately directly demonstrating neuronal activation compared to BOLD imaging, resulting in improved spatial and temporal resolution. ⋯ AS such, ASL is not widely used clinically and diffusion remains in the field of research. However, the increasing availability of 3T MR systems coupled with multi-channel surface coils and improved postprocessing techniques should improve the detection of the brain activation signal. It is thus possible that these techniques could become clinically available either in complement to or as a replacement for BOLD imaging.
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Given the increasing demand for interventional image-guided procedures, radiologists are increasingly sollicited by clinicians to participate in the management of patients prior to and after the interventional procedure, especially with regards to hemostasis. Therefore, radiologists should be familiar with the risk of procedure related hemorrhage. ⋯ Recommendations for preprocedure testing based on the type of procedure planned will be reviewed. Finally, limitations of hemostasis parameters will be discussed along with management of anticoagulants and antiplatelet agents before the procedure.
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The CT and MR imaging features of the main cardiac tumors will be reviewed. Cross-sectional imaging features may help differentiate between cardiac tumors and pseudotumoral lesions and identify malignant features. Based on clinical features, imaging findings are helpful to further characterize the nature of the lesion. CT and MR imaging can demonstrate the relationship of the tumor with adjacent anatomical structures and are invaluable in the presurgical work-up and postsurgical follow-up.
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Review Comparative Study
[CT features of right heart involvement in thoracic diseases].
Numerous respiratory disorders may be responsible for right heart dysfunction, frequently suboptimally assessed in routine clinical practice. Multidetector-row CT systems with fast scanning capabilities can acquire images of the thorax with reduced cardiac motion artifacts, enabling improved evaluation of the heart. Moreover, the introduction of fast rotation speed and dedicated cardiac reconstruction algorithms exploiting the multislice acquisition scheme of the data has opened the possibility of integrating right cardiac functional information into a diagnostic CT scan of the chest, without or with ECG gating.
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Chest radiographs and CT are especially useful for the follow-up of patients after lung resection. The purpose of this paper is to illustrate normal postsurgical imaging findings that differ according to the type of surgery (pneumonectomy, lobectomy, segmentectomy and wedge resection). Anatomic changes induced by surgery affect the remaining lung, pleura and chest wall, mediastinum and diaphragm. ⋯ After lobectomy, there is hyperexpansion of the remaining lung, mediastinal shift and intercostal space narrowing. Theses findings are different according to the delay after surgery. Knowledge of the variable imaging features is necessary to detect complications and to provide appropriate follow-up of the primary disease.