Details of left ventricular radial wall motion supporting the ventricular theory of the third heart sound obtained by cardiac MR.

OBJECTIVE: Obtaining new details of radial motion of left ventricular (LV) segments using velocity-encoding cardiac MRI. METHODS: Cardiac MR examinations were performed on 14 healthy volunteers aged between 19 and 26 years. Cine images for navigator-gated phase contrast velocity mapping were acquired using a black blood segmented κ-space spoiled gradient echo sequence with a temporal resolution of 13.8 ms. Peak systolic and diastolic radial velocities as well as radial velocity curves were obtained for 16 ventricular segments. RESULTS: Significant differences among peak radial velocities of basal and mid-ventricular segments have been recorded. Particular patterns of segmental radial velocity curves were also noted. An additional wave of outward radial movement during the phase of rapid ventricular filling, corresponding to the expected timing of the third heart sound, appeared of particular interest. CONCLUSION: The technique has allowed visualization of new details of LV radial wall motion. In particular, higher peak systolic radial velocities of anterior and inferior segments are suggestive of a relatively higher dynamics of anteroposterior vs lateral radial motion in systole. Specific patterns of radial motion of other LV segments may provide additional insights into LV mechanics. ADVANCES IN KNOWLEDGE: The outward radial movement of LV segments impacted by the blood flow during rapid ventricular filling provides a potential substrate for the third heart sound. A biphasic radial expansion of the basal anteroseptal segment in early diastole is likely to be related to the simultaneous longitudinal LV displacement by the stretched great vessels following repolarization and their close apposition to this segment.

Tips and traps in neurological imaging: imaging the perimedullary spaces.

The spinal canal is frequently a source of difficulties, traps and diagnostic errors. Pitfalls related to artifacts are resolved by using appropriate sequences. Good knowledge of the appearance of certain particular anatomical structures (the cauda equina roots, the radicular veins of the lumbar spine and conus medullaris, the dorsal root ganglion) and of frequent variants (fibrolipoma of the filum terminale, common root sheaths, root cysts) will avoid a good many errors. Dilatation of epidural veins in intracranial hypotension can simulate the contrast enhancement of a tumour. An increase in epidural fat can induce pathogenic stenosis of the dural sheath.

Magnetic resonance imaging of the breast: potential for lesion characterization.

PURPOSE: To study the diagnostic performance of conventional mammography and dynamic contrast-enhanced magnetic resonance mammography (MRM) with regard to the detection of breast malignancy and recognition of a multifocal cancer, in particular in a dense breast. MATERIALS AND METHODS: Patients with abnormal breast findings (n=93; 30 malignant and 63 benign) were examined by mammography, sonography and MRM. In all patients, high-quality two-view mammography and 7.5 MHz sonography of both breasts were performed before MRM. Images were acquired on 1.5T scanner system. All lesions had been histologically confirmed. RESULTS: The highest detection rate for multifocal invasive disease was seen with MRM, which identified 21 (72.5%) out of 29 histologically confirmed multifocal invasive cancers, whereas mammography identified 6 (20.5%) out of 24 (p=0.003). Lymph node metastases were present in 11 (37%) of 30 patients with malignant invasive carcinoma. MRM showed a sensitivity of 94.6%, specificity 78.5%, and accuracy 79.5%. CONCLUSION: Compared with triple assessment for clinically overt and occult breast disease, MRM offers higher sensitivity for the detection of multifocal cancer, which is important in selecting patients appropriate for breast-conserving surgery. In conclusion, the multiplanar capability of MRM enables it to provide more definite information than mammography and ultrasonography. MRM is presently able to better stage breast cancer locally and to measure more accurately breast cancer size, and determine multicentricity.