Two premature sibs had Potter sequence and died of respiratory failure within the first day. Ultrasonography at 26 weeks during the earlier of the two pregnancies showed complete absence of amniotic fluid, and the urinary bladder was not visualized. Ultrasound examinations during the second pregnancy showed adequate amniotic fluid at 16 and 20 weeks, with a subsequent reduction in fluid volume. Two older sibs had also died of respiratory failure shortly after birth. Postmortem histopathologic studies showed all four sibs to have severely deficient renal tubular development. However, the presence of numerous glomeruli indicated prolific nephrogenesis. Most of the tubules in sections of cortex had the lectin-binding and immunohistochemical characteristics of collecting ducts; proximal tubules were not identified by lectin-binding. Electron-microscopic examination showed a general absence of differentiated characteristics in cortical tubular epithelium, except that rare tubules contained rudimentary proximal tubular brush borders. Three of the sibs were boys, one a girl. The three children that were studied had normal chromosomes. Two unaffected sibs are alive and well. Neither parent has any clinical evidence of renal disease. These studies support the interpretation that renal tubular dysgenesis is autosomal recessive with pleiotropy. However, the relatively late appearance of oligohydramnios makes early diagnosis difficult, even when the condition is suspected.
Traditional film/screen mammograms are obtained using Molybdenum or Rhodium target x-ray tubes. The energy spectrum from these sources matches the limited latitude of film/screen systems. For digital imaging systems, the latitude is linear over a wide range of exposures and arbitrary H&D curves can be obtained with image processing. This allows the recorded contrast to noise ratio (CNR) to be optimized by considering a wide range of radiographic techniques. For this work, we modeled the radiographic process for a digital (amorphous selenium) mammography system. The optimal CNR relative to dose was determined for several target/filter combinations, for a wide range of kVp values, and for varying breast thickness. The target/filter combinations included: Mo/Mo, Mo/Rh, Rh/Rh, W/Al, W/Mo, W/Ag, and W/Sn. As breast thickness increased, the use of a tungsten target with a tin filter resulted in a 34% improvement in CNR for the same dose to the breast when compared to the use of a Molybdenum target with a Molybdenum filter. Notably, the W/Sn target/filter combination resulted in a significantly lower mA-s for the same breast dose (2/3 to 1/5 lower for a breast thickness from 4 to 8cm). In mammography applications, use of a Tungsten tube rather than the traditional Molybdenum tube should lead to significant reductions in exposure time and tube heat while maintaining similar image quality and dose.
This article reviews developmental skull anatomy, especially as it relates to the formation of cranial sutures and fontanelles, and demonstrates the appearance of these structures on prenatal sonograms, illustrating the framework these structures provide to enable one to accurately identify components of the fetal skull. Examples are provided to illustrate the utility of this knowledge. An understanding of fetal skull development and appearance enables the sonographer to better characterize fetal cranial abnormalities. More importantly, recognition of the location of cranial sutures and fontanelles and their ability to serve as acoustic windows assists the sonographer in evaluation of the fetal brain.
Breast MRI plays a critical role in the diagnosis and management of breast cancer. The purpose of this study is to evaluate the effect of preoperative breast MRI on the management of a large cohort of breast cancer patients at our institution. This study is a retrospective chart review of all newly diagnosed breast cancer patients who underwent preoperative breast MRI at our institution between January 1, 2004 and December 31, 2009. 1352 patients comprised the study population. 241 (17.8%) patients underwent a change in surgical management as a result of preoperative MRI. Patients with tumors in the lower inner quadrant and the central breast and those with pathology of invasive lobular carcinoma were significantly more likely to have their management changed by preoperative MRI. There was also a significant trend for larger tumors to be associated with a change in surgical management. No statistically significant association was found between breast density and change in management. This study supports the recommendation for the use of preoperative breast MRI in the majority of newly diagnosed breast cancer patients, especially those with larger tumors, pathology of invasive lobular carcinoma, and tumors in the lower inner quadrant. Preoperative breast MRI is a useful tool for the evaluation of additional disease that led to a change in the surgical management of 17.8% of patients.
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