Both PET/CT and whole-body MRI may distinguish benign and malignant PNSTs, but PET/CT has higher sensitivity for that purpose. Imaging-based criteria for identification of MPNSTs on both modalities were identified. False-positive results, requiring biopsy or clinical follow-up, may be reduced by using a combination of MRI and PET derived markers, but only at the price of reduced sensitivity.
The purpose of this study was to evaluate the usefulness of morphological criteria in differentiating between benign and malignant lesions on MR-mammography. Fifty-three women (18-82 years) with 62 lesions scheduled for excisional biopsy underwent dynamic contrast-enhanced MR-mammography using fast 3D Gradient-Echo sequences in coronal orientation (axial orientation in seven patients). Histology revealed 44 malignant and 18 benign lesions. For each lesion, five radiologists evaluated four morphological features: lesion shape, irregularity of contour, homogeneity of contrast enhancement and presence of ring enhancement. For each feature a receiver operating characteristic (ROC) curve was generated with calculation of the area under the curve (AUC). Interobserver variability was evaluated by the kappa-coefficient. The most reliable morphological feature indicating malignancy was an irregular lesion contour with a sensitivity/specificity/AUC of 83%/76%/0.9 followed by inhomogeneous contrast enhancement (85%/42%/0.7) and the presence of ring enhancement (71%/53%/0.64). The average interobserver agreement for the different features ranged between 0.35 and 0.4. Morphological criteria are useful features in MR-mammography for differentiating between benign and malignant lesions. However, due to the relatively high interobserver variability, standardization of terminology is important.
BOLD MR imaging can be used to measure changes of oxyhemoglobin saturation in fetal organs during hypoxia. The liver and heart demonstrated the greatest signal intensity decreases during hypoxia.
Purpose: To investigate MRI of the fetal heart by way of a novel triggering method with the use of an MR-compatible cardiotocography (CTG) in an animal model. Materials and Methods:Fetal cardiac MRI was performed on four pregnant ewes on a 1.5 Tesla (T) MR system. A CTG was rendered MR compatible and its signal was used for the triggering of the fetal heart to perform cardiac cine MRI of the fetal heart with maternal freebreathing with cine steady-state free precession. The left ventricular volume and function were measured from the short-axis (view). The image quality of anatomical structures was assessed.Results: All cardiac valves and the foramen ovale could be visualized. Myocardial contraction was depicted in cine sequences. The average blood volume at the end systole was 1.7 mL (SD 6 0.12). The average volume at the end diastole was 4.6 mL (6 0.4); thus the average stroke volumes of the left ventricle were 2.87 mL (6 0.31) with ejection fractions of 60.53% (6 4.17). Conclusion:The newly developed MR compatible CTG could be used as a tool for cardiac triggering method of the fetal heart. This novel device might help fetal cardiac MRI technology in the future. THE RAPID DEVELOPMENT of cardiac MR imaging in the past few years has enabled many different investigations, for example investigations into coronary arteries and myocardial infarctions. In practice, twodimensional (2D) CINE steady-state free precession (SSFP) imaging is the most reliable and frequently used technique for left ventricular (LV) function assessment. To assess the LV function correctly, speed as well as synchronization of data acquisition with the cardiac cycle are required, so that artifacts due to cardiac motion and flow constraints that dictate the viable window for data acquisition are avoided. To avoid the artifacts caused by cardiac motion, it is customary that either finger pulse oximetry or electrocardiography (ECG) triggering/gating techniques are used so that data acquisition can be synchronized with the cardiac cycle.Although the use of MR imaging during pregnancy is limited to the second and third trimester, its diagnostic value has been increasing in recent years. In the field of fetal MR imaging, the evaluation of the fetal heart is one of the greatest challenges. Nowadays, the gold standard in fetal cardiac imaging is the use of ultrasound (US), because it can be obtained during the entire pregnancy; it is easy to use and thus more practicable. Both the measurement of the cardiac volume and the evaluation of volumetric changes with US are possible, and the technology has been improving. Because cardiac chambers do not lend themselves to geometric assumptions, it has always been difficult to calculate their dimensions, even though studies have shown that 3D US has a better reproducibility than 2D (1-4). To be able to do so, it is necessary to trace the volume of the cardiac chambers manually, due to the appearance of various US specific artifacts, such as speckles and acoustic shadowing, which appear when traced automaticall...
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