Most (60%) of the patients with unilateral SNHL showed a significant difference in the diameters of the bony canals of the cochlear nerve between the affected and unaffected sides; moreover, the mean value was significantly smaller in affected ears. The diameter of < 1.7 mm on transverse images or < 1.8 mm on coronal images suggests hypoplasia.
The Japanese Society of Nuclear Medicine has recently published the consensus guidelines for pediatric nuclear medicine. This article is the English version of the guidelines. Part 1 proposes the dose optimization in pediatric nuclear medicine studies. Part 2 comprehensively discusses imaging techniques for the appropriate conduct of pediatric nuclear medicine procedures, considering the characteristics of imaging in children.
A case of microphthalmia with Xp microdeletion is reported. The patient was a boy who showed bilateral microphthalmia with corneal opacities, hypospadias without evidence of hypogonadism, and a conduction disturbance of the heart (Wenckebach conduction). No skin lesion was discerned. High-resolution chromosome analysis revealed the karyotype of 46,X,del(X)(p22). The phenotype was considered to be microphthalmia with linear skin defects (MLS) syndrome without skin lesions. Polymerase chain reaction and fluorescence in-situ hybridization analyses revealed that the chromosome aberration resulted from an X;Y translocation: the presence of pseudoautosomal boundary Y and the sex-determining region of Y was confirmed, while Xp deletion involving the region distal to DXS1129 was ascertained. Thus the chromosome designation using the ISCN 1995 nomenclature is 46,X,der(X),t(X;Y)(p22.13;q11.2). Despite the absence of skin lesions, the Xp deletion of our patient corresponded to those of previously reported typical cases of MLS syndrome. Our observation further supports the current hypothesis that the phenotypic variation of MLS syndrome represents tissue-different X inactivation rather than different genetic effects of two contiguous genes.
Purpose: To elucidate changes in the diŠusion properties of muscleˆber between rest and active contraction.Methods and materials: In 10 healthy adult volunteers (4 men, 6 women), we obtained diŠusion tensor (DT) images (b=500 s/mm 2 ) of bilateral calves using a 1.5-tesla clinical magnetic resonance (MR) imager. Weˆrst simultaneously scanned both calves at rest, then obtained scans of bilateral calves with plantar ‰exion of the right ankle using the same imaging parameters. We measured fractional anisotropy (FA) and l 1 , l 2 , and l 3 in the gastrocnemius medialis (GCM) and anterior tibialis (AT) muscles of both calves by seeding the region of interest at the thickest part, then calculated the right-to-left ratio of the FA and eigenvalues in each muscle and compared each ratio between rest and contraction by paired t-test.Results: In the GCM, the FA ratio increased from 1.05 at rest to 1.17 after contraction, and contraction elevated the l1 and 2 ratios from 0.99 in resting muscles to 1.06 (l 1 ) and 1.07 (l 2 ). In contrast, the AT showed a decrease of the l 1 ratio from 0.99 at rest to 0.96 at elongation and of the l 2 ratio, from and 1.01 at rest to 0.94 at elongation. Statistically signiˆcant diŠerences were observed in the FA (Pº0.05), l1 and l2 (Pº0.01) in the GCM, and the l1 and l2 (Pº0.05) in the AT.Conclusion: The higher FA and l 1 and l 2 values of muscles at contraction than rest presumably re‰ect complicated changes, including microscopic morphological changes of the diŠusion-restricting factor, focal temperature, and perfusion. We found that change in perfusion could aŠect the AT, and changes in focal perfusion and temperature could in‰uence the GCM.
Children with cancer are at increased risk of life-threatening emergencies, either from the cancer itself or related to the cancer treatment. These conditions need to be assessed and treated as early as possible to minimize morbidity and mortality. Cardiothoracic emergencies encompass a variety of pathologies, including pericardial effusion and cardiac tamponade, massive hemoptysis, superior vena cava syndrome, pulmonary embolism, and pneumonia. Abdominal emergencies include bowel obstruction, intussusception, perforation, tumor rupture, intestinal graftversus-host disease, acute pancreatitis, neutropenic colitis, and obstructive uropathy. Radiology plays a vital role in the diagnosis of these emergencies. We here review the clinical features and imaging in pediatric patients with oncologic emergencies, including a review of recently published studies. Key radiological images are presented to highlight the radiological approach to diagnosis. Pediatricians, pediatric surgeons, and pediatric radiologists need to work together to arrive at the correct diagnosis and to ensure prompt and appropriate treatment strategies.
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