To establish the normal appearance of the neonatal brain, 51 neonates, 29-42 weeks postconception, underwent magnetic resonance (MR) imaging with a 0.6-T magnet in a prospective study. T1-weighted images were used to devise stages for the appearance of gray-white matter differentiation and extent of myelination. The results show that from 29 to 42 weeks postconception, changes in gray-white matter differentiation and myelination follow the stages in an orderly and predictable fashion. Changes in white matter intensity appear related to progressive decrease in brain water content. Myelination progresses cephalad from the brain stem at 29 weeks to reach the centrum semiovale by 42 weeks. Delayed myelination, defined as the absence of myelin in the corona radiata by 37 weeks, was seen in nine infants with complicated perinatal courses. Awareness of these developmental features should help to minimize misinterpretation of normal changes in the neonatal brain and lead to earlier detection of pathologic conditions, both with MR imaging and computed tomography.
We reviewed eight cases of gastrointestinal duplication cysts to determine whether the combination of an echogenic inner mucosal layer and hypoechoic outer muscular layer could be seen consistently enough to be of diagnostic value. We compared our findings to those seen in twenty-seven other abdominal cysts and conclude that when identified together, the two layers are highly suggestive, if not completely diagnostic of enteric duplication cysts.
Ultrasonography has been shown to be valuable in the detection of intussusception, but a question arises, as to just when this study should be performed. Should it be a general screening procedure or should it be utilized for specific cases only? Upon reviewing the literature, and the findings in 14 of our patients, we feel that it should be utilized as a general screening procedure. In addition, we offer a different explanation for the typical doughnut and pseudokidney signs seen with intussusception.
The authors reviewed the ultrasonographic (US) images and medical records of 145 consecutive infants who were seen for evaluation of the upper gastrointestinal tract because of chronic vomiting and/or regurgitation. At US, the antropyloric muscle of each patient was measured in the midlongitudinal plane. On the basis of this measurement, the patients were divided into the following categories: group 1 (1-2 mm; 99 patients), group 2 (greater than or equal to 3 mm; 40 patients), and group 3 (2- less than 3 mm; six patients). Patients in group 1 were considered to have normal antropyloric muscle thickness, those in group 2 had abnormal thickness, and those in group 3 had muscle thickness that was not definitely normal or abnormal. The final clinical diagnoses for all of the infants in the three groups confirmed the authors' initial impressions that antropyloric muscle thickness of less than 2 mm was anatomically normal, muscle measuring 3 mm or greater was abnormal and diagnostic for pyloric stenosis, and muscle from 2 to less than 3 mm was abnormal but not specifically diagnostic for pyloric stenosis. Two of the six patients in group 3 eventually were diagnosed as having pyloric stenosis; thus, the authors believe that only those patients with antropyloric muscle less than 2 mm thick should be considered unequivocably normal.
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