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Susceptibility-weighted imaging (SWI) consists of using both magnitude and phase images from a high-resolution, three-dimensional, fully velocity compensated gradientecho sequence. Postprocessing is applied to the magnitude image by means of a phase mask to increase the conspicuity of the veins and other sources of susceptibility effects. This article gives a background of the SWI technique and describes its role in clinical neuroimaging. SWI is currently being tested in a number of centers worldwide as an emerging technique to improve the diagnosis of neurological trauma, brain neoplasms, and neurovascular diseases because of its ability to reveal vascular abnormalities and microbleeds.

A woman 45 years of age or older is considered to be of very advanced maternal age. In Australia, 0.1% of parturients are in this category at present. The investigators undertook a retrospective cohort study of women aged 45 or above at the time of delivery, all of whom delivered at 20 or more weeks of gestation. In the 108,818 women reviewed, 76 women of very advanced maternal age had 77 pregnancies (incidence ϭ 0.7 per 1000 births). The mean age was 46 years. Sixteen women in the study were primiparous. In multiparas, a mean of 8.8 years had passed since the last live birth. More than half the women had had at least one miscarriage and 13 (17% of the total) reported having 3 or more. Only 14% of women required assisted reproduction. The most frequent medical problems were depression, present in 9 women, and uterine leiomyomas in 4. No chromosomal abnormalities were found in the 53% of pregnancies that were evaluated.Two thirds of pregnancies were free of complications. Ten women had pregnancy-related hypertensive disorders compared with 10% of women 20 to 29 years of age. Two women were delivered before term because of preeclampsia. Gestational diabetes was diagnosed in 8% of pregnancies; only one woman received insulin. Labor began spontaneously in 36% of pregnancies and was induced in 17%, most often "electively" or because of postdate status or spontaneous rupture of membranes at term. The rate of cesarean section was 49% compared with 23% in the younger women. Four women required manual removal of the placenta because of bleeding, and 3 had postsection wound infections.Eight of 78 live-born infants were small-for-gestational age, whereas 6 were large-for-gestational age. Seven singleton births and both sets of twins were born prematurely for a variety of reasons, the most common being premature rupture of membranes. Thirteen infants, 17% of the total, were admitted to the special care nursery; prematurity and respiratory distress syndrome accounted for 6 and 4 admissions, respectively. The overall rate of special care was 16.5%. Five infants in the study group (6%) had congenital abnormalities.The findings in this large-scale study of women aged 45 or above are, in general, reassuring for older women who are in good health and who have a chromosomally normal fetus.

Purpose:To compare the sensitivity of magnetic resonance (MR) susceptibility-weighted imaging (SWI) with conventional MR sequences and computed tomography (CT) in the detection of hemorrhage in an acute infarct. Materials and Methods:A series of 84 patients suspected of having acute strokes had both CT and MR imaging (MRI) scans with diffusion-weighted imaging (DWI) and SWI. The SWI sequence is a new high-resolution three-dimensional (3D) imaging technique that amplifies phase to enhance the magnitude contrast.Results: Thirty-eight of 84 cases showed abnormal DWI consistent with acute infarct. Of the 38, SWI showed evidence of hemorrhage in 16 cases, compared to eight cases with spin echo (SE) T2, seven cases with fluid attentuated inversion recovery (FLAIR), and only five cases with CT. In a subset of 17 cases of acute infarct who had both twodimensional gradient recalled echo (2D-GRE) T2*-weighted imaging and SWI, in addition to conventional MRI, evidence of hemorrhage was seen in 10 cases using SWI, compared to seven cases with 2D-GRE T2*.Conclusion: SWI proved to be a powerful new approach for visualizing hemorrhage in acute stroke compared to CT and conventional MRI methods.