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The effect of chemical shift on magnetic resonance (MR) imaging of the pituitary fossa was studied. Healthy volunteers underwent conventional MR imaging of the pituitary fossa and then imaging with the frequency-encoding gradient reversed or with the phase- and frequency-encoding gradients interchanged. Comparison of the image pairs in each subject showed that the thin, black stripe evident at the water-fat interface within the pituitary fossa was altered when the gradients were changed. Therefore, the low-intensity signal within the pituitary fossa is a chemical shift misregistration effect. 相似文献
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Anulus fibrosus in bulging intervertebral disks 总被引:1,自引:0,他引:1
In this investigation the association of radial tears of the anulus fibrosus and bulging of the intervertebral disk was studied. An index of disk bulging was measured in sagittal anatomic sections in 149 lumbar disks from 31 cadavers. The indexes of disk bulging were correlated with stages of disk development and the presence of an annular tear. The largest disk-bulging indexes were always associated with radial tears of the anulus. Eighty-four percent of the disks with radial tears had disk-bulging indexes greater than 2.5 mm. Most normal adult disks had an index of less than 2.5 mm. The results challenge the concept that the anulus fibrosus is intact in bulging disks, although ruptured in herniated disks. 相似文献
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Sanjana VM; Johnston PA; Robertson CR; Jamison RL 《The American journal of physiology》1976,231(2):313-318
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Frints SG Jun L Fryns JP Devriendt K Teulingkx R Van den Berghe L De Vos B Borghgraef M Chelly J Des Portes V Van Bokhoven H Hamel B Ropers HH Kalscheuer V Raynaud M Moraine C Marynen P Froyen G 《American journal of medical genetics. Part A》2003,(3):367-374
We describe a 59-year-old male (patient A059) with moderate to severe mental retardation (MR) and a pericentric inversion of the X-chromosome: inv(X)(p21.1;q22.1). He had short stature, pectus excavatum, general muscle wasting, and facial dysmorphism. Until now, no other patients with similar clinical features have been described in the literature. Molecular analysis of both breakpoints led to the identification of a novel "Nuclear RNA export factor" (NXF) gene cluster on Xq22.1. Within this cluster, the NXF5 gene was interrupted with subsequent loss of gene expression. Hence, mutation analysis of the NXF5 and its neighboring homologue, the NXF2 gene was performed in 45 men with various forms of syndromic X-linked MR (XLMR) and in 70 patients with nonspecific XLMR. In the NXF5 gene four nucleotide changes: one intronic, two silent, and one missense (K23E), were identified. In the NXF2 gene two changes (one intronic and one silent) were found. Although none of these changes were causative mutations, we propose that NXF5 is a good candidate gene for this syndromic form of XLMR, given the suspected role of NXF proteins is within mRNA export/transport in neurons. Therefore, mutation screening of the NXF gene family in phenotypically identical patients is recommended. 相似文献
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Rao VM; Dalinka MK; Mitchell DG; Spritzer CE; Kaplan F; August CS; Axel L; Kressel HY 《Radiology》1986,161(1):217-220
Four patients with proved osteopetrosis (three with the infantile malignant form and one with the benign form) were examined with magnetic resonance imaging at 1.5 T. All patients were studied in the coronal and sagittal planes using both short and long repetition time/echo time sequences. The infantile malignant form was characterized by a complete lack of signal from the marrow alternating with a signal intensity equivalent to that of the intervertebral disks, resulting in a "stepladder" appearance. In the benign form or after successful marrow transplantation in the infantile malignant form, intermediate or high signal intensity in the vertebrae was noted, suggesting the presence of some marrow elements. 相似文献