Context Morbidity and mortality rates in hemodialysis patients remain excessive. Alterations in the delivery of dialysis may lead to improved patient outcomes. Objective To compare the effects of frequent nocturnal hemodialysis vs conventional hemodialysis on change in left ventricular mass and health-related quality of life over 6 months. Design, Setting, and Participants A 2-group, parallel, randomized controlled trial conducted at 2 Canadian university centers between August 2004 and December 2006. A total of 52 patients undergoing hemodialysis were recruited. Intervention Participants were randomly assigned in a 1:1 ratio to receive nocturnal hemodialysis 6 times weekly or conventional hemodialysis 3 times weekly. Main Outcome Measures The primary outcome was change in left ventricular mass, as measured by cardiovascular magnetic resonance imaging. The secondary outcomes were patient-reported quality of life, blood pressure, mineral metabolism, and use of medications. Results Frequent nocturnal hemodialysis significantly improved the primary outcome (mean left ventricular mass difference between groups, 15.3 g, 95% confidence interval [CI], 1.0 to 29.6 g; P=.04). Frequent nocturnal hemodialysis did not significantly improve quality of life (difference of change in EuroQol 5-D index from baseline, 0.05; 95% CI, −0.07 to 0.17; P=.43). However, frequent nocturnal hemodialysis was associated with clinically and statistically significant improvements in selected kidney-specific domains of quality of life (P=.01 for effects of kidney disease and P=.02 for burden of kidney disease). Frequent nocturnal hemodialysis was also associated with improvements in systolic blood pressure (P=.01 after adjustment) and mineral metabolism, including a reduction in or discontinuation of antihypertensive medications (16/26 patients in the nocturnal hemodialysis group vs 3/25 patients in the conventional hemodialysis group; PϽ.001) and oral phosphate binders (19/26 patients in the nocturnal hemodialysis group vs 3/25 patients in the conventional dialysis group; PϽ.001). No benefit in anemia management was seen with nocturnal hemodialysis. Conclusion This preliminary study revealed that, compared with conventional hemodialysis (3 times weekly), frequent nocturnal hemodialysis improved left ventricular mass, reduced the need for blood pressure medications, improved some measures of mineral metabolism, and improved selected measures of quality of life.

When accurate assessment of residual enhancing tumor is needed in patients with malignant glioma, an MR scan performed on postoperative days 3 to 5 should minimize the confounding effects of postsurgical enhancement and methemoglobin. The repeated administration of Gd-DTPA over several weeks is well tolerated.

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Purpose: To refine and evaluate methods for analysis of renal blood oxygenation level dependent (BOLD) MRI data. Materials and Methods:Color R2* maps and regions-ofinterest (ROIs) on the borderline between cortex and medulla were applied to renal BOLD MRI data of a group of 13 young female subjects. Results:The distribution of R2* within the kidneys was heterogeneous and the response of human kidneys to water diuresis was patchy. R2* values at the cortico-medullary border region have a smaller variation than in wider cortical or medullary regions and are sensitive to physiological changes produced by water diuresis. Conclusion:These methods provide improved visualization of the regional distribution of R2* and its variations and more precise quantification of the changes in renal R2* produced by water diuresis. BOLD MRI SIGNALS have previously been shown to correlate with oxygenation of hemoglobin in blood (1-4) and have been used to study renal tissue oxygenation during diuresis induced by water ingestion or by diuretics (5-8).The counter-current arrangement of capillary blood flow in the medulla of mammalian kidneys generates a gradient of oxygen tension between the renal cortex and the papillary tip that results in a state of relative hypoxia within the renal medulla, with important implications for renal physiology and disease (9 -11). The noninvasive technique of BOLD MRI can, in theory, permit the investigation of regional oxygenation of the kidney in normal human subjects and in disease states (5,13). It is therefore important to develop and refine techniques of obtaining and analyzing BOLD MRI images of the kidney that are precise and reproducible.The method of analyzing renal BOLD MRI data in previous studies has involved generating an R2* map in gray scale from a series of multi-TE gradient echo images. From these R2* maps a number of regions-ofinterests (ROIs) were selected at random in the medulla and cortex throughout the kidney. Mean R2* values and associated variances in the medulla and cortex were calculated in order to estimate changes in medullary or cortical oxygenation associated with diuresis (5,6). Owing to the complicated anatomy of the human kidney (Fig. 1a) and the random and arbitrary nature of ROI placement, a large variance of the averaged R2* values may obscure and limit the precise application of BOLD MRI to probe renal functions (12).Hypothesizing that visual assessment in conjunction with proper numerical sampling would improve our ability to extract information from renal BOLD MRI data, we have recently developed a color map scheme as a graphic alternative to access R2* changes within the kidney in conjunction with quantitative analysis of ROIs in borderline areas between the medulla and cortex (Fig. 1b). We have applied this method to BOLD MRI data of a group of normal subjects who underwent water diuresis. This paper communicates our results of utilizing the R2* color map and ROIs in borderline areas to assess the R2* changes produced in normal human kidneys by water diuresis.