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991.
Spatial resolution requirements for digital chest radiographs: an ROC study of observer performance in selected cases 总被引:3,自引:0,他引:3
Thirty-eight selected clinical radiographs were digitized and displayed on a 1,024-line monitor at pixel sizes of 1.6, 0.8, 0.4, and 0.2 mm. Eighteen experienced radiologists assessed the radiographs and digital images, which included 12 examples of abnormal solitary nodular density, ten examples of septal lines, and 16 controls, six of which showed diffuse lung abnormalities. For each level of spatial resolution and for film reading, observers gave their decision confidence on a sliding scale of probability. Receiver operating characteristic curves were generated from these data. It was found that while spatial resolution requirements for solitary nodules were not critical for pixel sizes at or below 0.8 mm, the requirement for septal lines was likely to be 0.4 mm (1.25 line pairs/mm). 相似文献
992.
Pretorius DH; Rumack CM; Manco-Johnson ML; Manchester D; Meier P; Bramble J; Clewell W 《Radiology》1986,159(1):237-242
A retrospective study was performed of 13 short-limbed fetuses with lethal skeletal dysplasias that were evaluated with ultrasound (US) from 1981 to 1984. The specific diagnoses were thanatophoric dwarfism, achondrogenesis, osteogenesis imperfecta, and campomelic dwarfism. Death occurred in utero or within 2 weeks after delivery in all cases. US examination showed other associated abnormalities, including polyhydramnios, hydrops, shortened femurs, and CNS abnormalities. Radiographs confirmed these findings and provided more information regarding the shape of the limbs and thorax and the appearance of the spine. The probable diagnosis of lethal short-limbed dwarfism was made antenatally using US in eleven of the fetuses. Spinal appearance, thoracic shape, and associated hydrops and polyhydramnios were most helpful in determining the specific type of dysplasia present. Lethal short-limbed skeletal dysplasia may be diagnosed confidently in utero using US examination; however, obstetric plain film radiography may be required to determine the definitive type of dysplasia. In certain cases, US may be sufficient to make a definitive diagnosis. 相似文献
993.
994.
Murray RR Jr; Hewes RC; White RI Jr; Mitchell SE; Auster M; Chang R; Kadir S; Kinnison ML; Kaufman SL 《Radiology》1987,162(2):473-476
Analysis of 193 femoropopliteal angioplasties demonstrated patency rates in the stenotic group of 75.5% at 6 months and 54.4% at 54 months. The patency rates for the occlusive group were 93.7% at 6 months and 72.9% at 54 months; these rates were significantly better than those in patients with stenoses. A group of 14 patients with long-segment (greater than 7 cm) stenosis had the highest risk of early failure, with a 6-month patency of 23.1%. After removal of the long-segment stenosis group from the results, there were no significant differences between the long-term patencies for stenotic and occlusive lesions. If angioplasty of long stenoses is attempted, a high initial success rate but early failure should be anticipated. 相似文献
995.
996.
重型颅脑损伤后高血糖82例 总被引:1,自引:1,他引:0
1 临床资料 1996 - 0 8/ 1999- 0 8我科共收治重型颅脑损伤患者 82 (男 5 8,女 2 4)例 ,年龄 7~ 81(平均 32 .4)岁 .本组患者伤前均无糖尿病史 .GCS评分均 <8分 .其中 6~ 8分的 42例 ;3~ 5分的 2 8例 ;3分以下的 12例 .发病至入院时间均在2 4h以内 .应用美国产“One Touch”血糖仪每日在床旁测空腹血糖 1次[1 ] ,连续测 7d.对于空腹血糖 >10 mmol· L者 ,给予低糖饮食 ,不用激素 ,少量应用甘露醇 ,适当应用胰岛素及乳酸林格液等治疗 .在 82例中 ,首次测血糖值 >10 mmol· L[2 ] 的 49例 ,最高值为 19.4mmol· L ;经上述治疗 ,结果… 相似文献
997.
Double-strand breaks may initiate the inversion mutation causing the Hunter syndrome 总被引:2,自引:2,他引:2
Lagerstedt K; Karsten SL; Carlberg BM; Kleijer WJ; Tonnesen T; Pettersson U; Bondeson ML 《Human molecular genetics》1997,6(4):627-633
We have previously shown that patients with the Hunter syndrome frequently
have suffered from a recombination event between the IDS gene and its
putative pseudogene, IDS-2, resulting in an inversion of the intervening
DNA. The inversion, which might be the consequence of an intrachromosomal
mispairing, is caused by homologous recombination between sequences located
in intron 7 of the IDS gene and sequences located distal of exon 3 in
IDS-2. In order to gain insight into the mechanisms causing the inversion,
we have isolated both inversion junctions in six unrelated patients. DNA
sequence analysis of the junctions showed that all recombinations have
taken place within a 1 kb region where the sequence identity is >98%. An
interesting finding was the identification of regions with alternating IDS
gene and IDS-2 sequences present at one inversion junction, suggesting that
the recombination event has been initiated by a double-strand break in
intron 7 of the IDS gene. The results from this study suggest that
homologous recombination in man could be explained by mechanisms similar to
those described for Saccharomyces cerevisiae. The results also have
practical implications for diagnosis of patients with the Hunter syndrome.
相似文献
998.
Anterior knee pain: the use of computerized tomography to assess the results of tibial tubercle transfer 总被引:1,自引:0,他引:1
Anterior knee pain is a common clinical problem. Patient assessment is difficult. Recently, it has been suggested that the so-called ‘skyline’ views of the patellofemoral joint have no role to play in screening for maltracking and some would suggest that computerized tomography (CT) offers a more accurate method of investigation. The aim of this study was to evaluate the performance of CT in the assessment of three populations: patients suffering form anterior knee pain, patients treated for this condition by tibial tubercle transfer and a control group. The patellofemoral joint was assessed by measuring the trochlear angle, the congruence angle and the patella tilt from the CT images. In summary, the preoperative group had significantly different values of each parameter when compared with other groups but the group that had undergone surgical correction did not demonstrate a significant alteration toward the values of the control group. This study suggests that CT was not useful as either a diagnostic tool or as a indicator of successful surgical outcome. 相似文献
999.
1000.