Ophthalmic artery peak systolic velocity ratio distinguishes pre-eclampsia from chronic and gestational hypertension: A prospective cohort study.

OBJECTIVE: To examine whether the ophthalmic artery peak systolic velocity ratio (OA PSV-ratio) is higher in women with pre-eclampsia compared with gestational hypertension (GH) and chronic hypertension (CH), after controlling for confounding variables. DESIGN: Prospective cohort. SETTING: Specialist hypertension clinic in a tertiary referral centre. POPULATION: Singleton pregnancies presenting between 32+0 and 36+6  weeks of gestation with pre-eclampsia (n = 50), GH (n = 54) and CH (n = 56). METHODS: Paired measurements of maternal mean arterial pressure (MAP) and OA PSV-ratio were performed by trained sonographers. Multiple linear regression was fitted to the OA PSV-ratio, including maternal characteristics and medical history, GH, pre-eclampsia and MAP and use of antihypertensive medication. MAIN OUTCOME MEASURE: Whether pre-eclampsia is independently associated with higher OA PSV-ratio. RESULTS: MAP was significantly higher in both GH (p = 0.0015) and pre-eclampsia (p = 0.008) than in CH pregnancies. There was no significant difference between pre-eclampsia and GH (0.670). The OA PSV-ratio was significantly higher in pre-eclampsia than CH (p = 0.0008) and GH (p = 0.015). There was no significant difference between the OA PSV-ratio in CH and GH (p = 0.352). Multiple linear regression modelling showed that the OA PSV-ratio was influenced by maternal weight (p = 0.005), maternal age (p = 0.014), antihypertensive medications (p = 0.007) and MAP (p < 0.0001). After controlling for these variables, the OA PSV-ratio was still significantly higher in those with pre-eclampsia (p = 0.0002). CONCLUSIONS: The OA PSV-ratio is influenced by maternal weight, age, antihypertensive medications and MAP. Pre-eclampsia is an independent predictor of OA PSV-ratio, which therefore may be a useful point-of-care test when assessing women presenting with hypertension.

Radiation dose reduction for augmentation mammography.

OBJECTIVE: Patients who undergo cosmetic augmentation have larger and denser breasts and receive higher radiation doses during mammography than women without implants. In this study we evaluated the dose increase and techniques for dose reduction. SUBJECTS AND METHODS: Mean glandular dose to the breast during screening mammography was measured for 206 women who had undergone breast augmentation. For 13 of these women, mean glandular dose from preoperative mammography also was measured. Effective tube current, peak kilovoltage, and breast thickness were measured, and mean glandular dose was calculated for 1,632 images. Two screen-film combinations and three target-filter combinations were studied. RESULTS: For four-view augmentation mammography with a molybdenum-molybdenum (Mo-Mo) target-filter combination, mean glandular dose was reduced 35%, from 10.7 to 7.0 mGy, by changing the screen-film combination from 100 to 190 speed. For four-view augmentation mammography, mean glandular dose was reduced 24% by changing the target-filter combination from Mo-Mo to rhodium-rhodium (Rh-Rh) for full views of breasts containing implants. For four-view augmentation mammography, mean glandular dose was reduced 50% by changing the screen-film combination from 100 to 190 speed and changing the target-filter combination from Mo-Mo to Rh-Rh for implant-full views. CONCLUSION: Mean glandular dose per breast from four-view augmentation mammography with the 100-speed screen-film and Mo-Mo target-filter combinations averaged 10.7 mGy, which is 3.1 times higher than the 3.4 mGy for conventional two-view mammography of breasts without implants. In 40 years of screening, this number represents a more than tripled lifetime attributable risk of radiation-induced breast cancer--an unacceptable level. Use of faster screen-film combinations, use of Rh-Rh target-filter combinations, and acquisition of three rather than four views are dose-reduction methods that together result in a 66% dose reduction, from 10.7 to 3.6 mGy. Mean glandular dose should be kept less than 7.0 mGy per breast for screening mammography of patients with breast implants.