Ishijima H, Ishizaka H, Horikoshi H, Sakurai M
Department of Diagnostic Radiology, Gunma University Hospital, Japan.
AJR Am J Roentgenol. 1996 Aug;167(2):355-8. doi: 10.2214/ajr.167.2.8686603.
Our objective was to use the chemical-shift misregistration effect of MR imaging to measure the variation in the water fraction in vertebral bone marrow with respect to patient age and sex.
We examined prospectively 211 subjects (5-84 years old; 108 male and 103 female subjects) who had no history of hematologic disorders. We obtained midsagittal proton density-weighted spin-echo images (2500/22 [TR/TE]) with a narrow sampling bandwidth (6250 Hz). Misregistered signals from lipid protons of 6-10 mm (upward shift in the readout direction) were obtained with the chemical-shift effect. By measuring the mean signal intensities of the water voxels and the water-plus-lipid voxels, we calculated a region of interest in each vertebral body for L1 to L3. The water fraction of bone marrow was then calculated as 100 x (signal intensity of water voxels/signal intensity of water-plus-lipid voxels). Individual water fractions were calculated from the average values for the water fractions of the L1-L3 bodies.
In the male subjects, the water fraction showed a rapid decrease in the older patients in the 5- to 34-year-old group. (Mean water fractions for male patients who were 5-14, 15-24, and 25-34 years old were 75.2%, 69.0%, and 53.7%, respectively.) For male patients more than 25 years old, the water fraction remained almost constant (approximately 50%). In female subjects who were 5-44 years old, the water fraction exceeded 69% and remained almost constant. However, the water fraction rapidly decreased in women more than 45 years old. (Mean water fractions for female patients who were 35-44, 45-54, and 55-64 years old were 70.9%, 61.1%, and 49.7%, respectively.) A comparison between male subjects and female subjects showed that the water fraction for women who were 25-54 years old exceeded the water fraction for men in the same age group (25-34 years old, p < .0001; 35-44 years old, p < .001; 45-54 years old, p < .05).
MR imaging showed that male and female subjects convert hematopoietic marrow to fatty marrow in the lumbar vertebral bodies in significantly different ways. The data obtained for the normal water fraction of bone marrow may prove useful for evaluating diseases that affect marrow.
我们的目的是利用磁共振成像的化学位移配准误差效应来测量椎体骨髓中水分含量随患者年龄和性别的变化。
我们前瞻性地检查了211名无血液系统疾病病史的受试者（年龄5 - 84岁；男性108名，女性103名）。我们获取了矢状面中部质子密度加权自旋回波图像（2500/22 [TR/TE]），采样带宽较窄（6250 Hz）。利用化学位移效应获取6 - 10 mm脂质质子的配准误差信号（读出方向上的向上偏移）。通过测量水像素和水加脂质像素的平均信号强度，我们计算了L1至L3每个椎体的感兴趣区域。然后将骨髓的水分含量计算为100×（水像素的信号强度/水加脂质像素的信号强度）。个体水分含量由L1 - L3椎体水分含量的平均值计算得出。
在男性受试者中，5至34岁年龄组的老年患者水分含量迅速下降。（5 - 14岁、15 - 24岁和25 - 34岁男性患者的平均水分含量分别为75.2%、69.0%和53.7%。）对于25岁以上的男性患者，水分含量几乎保持恒定（约50%）。在5至44岁的女性受试者中，水分含量超过69%且几乎保持恒定。然而，45岁以上女性的水分含量迅速下降。（35 - 44岁、45 - 54岁和55 - 64岁女性患者的平均水分含量分别为70.9%、61.1%和49.7%。）男性受试者与女性受试者的比较表明，25至54岁女性的水分含量超过同年龄组男性（25 - 34岁，p < .0001；35 - 44岁，p < .001；45 - 54岁，p < .05）。
磁共振成像显示，男性和女性受试者将腰椎椎体中的造血骨髓转化为脂肪骨髓的方式存在显著差异。所获得的正常骨髓水分含量数据可能有助于评估影响骨髓的疾病。
