白血病骨髓移植的MRI研究

目的 研究ＭＲＩ对白血病骨髓移植（ＢＭＴ）患者骨髓变化的评估作用和价值。方法 共２０例白血病ＢＭＴ患者,分别在ＢＭＴ前后行ＳＥ序列Ｔ１ＷＩ和脂肪抑制成像;并测量腰椎骨髓Ｔ１弛豫时间。结果 １７例ＢＭＴ后骨髓在Ｔ１ＷＩ上信号强度升高复发率５．８８％;３例信号无变化者,复发率６６．７０％;两组间复发率差异具有显著性意义（Ｐ〈０．０５）;ＢＭＴ后腰椎骨髓Ｔ１值低于正常值（Ｐ〈０．０５）;与ＢＭＴ前相比,     

弥漫性骨髓疾病的MRI诊断：附22例分析

本文分析了２２例经骨髓穿刺证实的弥漫性骨髓疾病的ＭＲＩ表现。其中儿童急性淋巴细胞性白血病（ＡＬＬ）１６例，成人髓细胞性白血病１例，神经母细胞瘤骨髓转移２例，多发性骨髓瘤２例，高雪氏病１例。对１６例ＡＬＬ进行了定量研究（Ｔ１和Ｔ２值测定）。对上述各种疾病的病理改变及ＭＲＩ表现进行了讨论。结果表明ＭＲＩ对评价弥漫性骨髓疾病具有重要临床价值。     

脊柱多发性骨髓瘤的MRI表现

目的：探讨脊柱多发性骨髓瘤的ＭＲＩ表现。方法：对２０例经骨髓穿刺证实的多发性骨髓瘤进行了下位胸椎和腰椎的常规Ｘ线和ＭＲＩ检查。根据ＭＲＩ信号异常的形态特点分为３型：局灶型、混杂型和弥漫型。结果：１２例ＭＲＩ信号异常，其中局灶型７例、混杂型２例和弥漫型３例。９例表现为Ｔ１ＷＩ低信号和Ｔ２ＷＩ高信号，且均未经治疗。５例的血红蛋白（１００ｇ／Ｌ和血清钙）２．５ｍｍｏｌ／Ｌ，均未经治疗，其中局灶型３例和混杂型２例。７例椎体压缩性骨折，其中仅２例是局灶型。结论：多发性骨髓瘤的脊柱ＭＲＩ检查有助于对其骨髓侵犯的检出。分型可能有助于对椎体压缩性骨折和贫血、高钙血症的认识。ＭＲＩ信号特点可以与是否经治疗有关。     

急性白血病骨髓PRI定性和定量诊断价值

目的 通过观察急性白血病有后骨髓的ＭＲＩ表现和Ｔ１及对比噪声比（ＣＮＲ）的测定，对照临床、病理资料，探讨急性白血病骨髓ＭＲＩ定性和定量诊断价值。材料与方法 选择经临床确诊为急性白血病的患者３８例，缓解组２５例，对照组３５例进行ＭＲＩ检查及Ｔ１值和ＣＮＲ的测定。结果 急性白血病Ｔ１ＷＩ：治疗前组３８例，腰骶椎、髂骨及股骨近段均表现为信号降低；化疗缓解组２５例表现为不同程度的信号增高。Ｔ２ＷＩ：３８例     

涎腺肿瘤的MRI诊断

笔者对６３例涎腺肿瘤的ＭＲＩ征象与手术病理进行对照。肿瘤的边界、包膜、Ｔ２弛豫时间和Ｔ２加权像上的信号强度是鉴别肿瘤良恶性的主要依据，并认为ＭＲＩ对肿瘤与其他疾病的鉴别，腮腺肿瘤的深浅叶定位和与面神经的关系及腮腺内外肿瘤的鉴别具有重要的临床价值。     

脑血肿MRI诊断与研究（附108例分析）

对１０８例原发性脑血肿分成大小两种血肿进行ＭＲＩ表现分析，并与其Ｔ１和Ｔ２弛豫时间进行对照性研究。结果发现小血肿ＭＲＩ表现及Ｔ１和Ｔ２值变化快于大血肿，尤其在急性期和亚急性早期更加明显，此外血肿Ｔ１和Ｔ２值的演变过程为由长变短再延长，而Ｔ２值缩短早在急性期即可出现，此过程反映了脑血肿病理变化和血红蛋白演变的规律即ＨｂＯ２→ＤＨｂ→ＭＮｂ→Ｈ－Ｓ。     

脑干胶质瘤的磁共振诊断

分析脑干胶质瘤的ＭＲＩ特征及与肿瘤分级的关系。材料和方法：搜集１９８８－１９９４年间经手术与病理证实２４例和活检证实１例，其中内生型２１例（８４％）（局限型１１例、弥漫型９例、延颈型１例）；外生型３例；播散型１例。２５例作ＭＲＩ平扫，６例还作Ｇｄ－ＤＴＰＡ静脉注射后ＭＲ成像。结果：ＭＲＩ上，脑干胶质瘤呈局限性膨胀或弥漫性增粗；在Ｔ１ＷＩ肿瘤多呈低、略低信号（５６％），Ｔ２ＷＩ多呈高信号（９３％），增强后实质部分强化，囊变区不强化；肿瘤包裹基底动脉并使之前移（６４％）；环池和桥小脑角池变窄或闭塞（９２％）。７３％局限型为Ⅰ级，８９％弥漫型为Ⅱ－Ⅲ级。结论：ＭＲＩ对全面显示肿瘤及脑干邻近解剖结构十分有效，术前定位诊断正确率达１００％，定性诊断正确率为９２％，分型正确率为８４％。肿瘤分型与病理分级显著相关（Ｐ＜０．０１）。     

小儿血液系统常见疾病的骨髓MRI表现

目的：探讨小儿血液系统常见疾病的骨髓 ＭＲＩ 表现。材料和方法：贫血２１ 例（ 缺铁性３ 例;巨细胞性２ 例,出血性２ 例,溶血性１ 例,再障性１３ 例） ;白血病１４ 例。正常对照组２２ 例。用０．３５Ｔ ＭＲＩ 机,ＳＥ、ＳＴＩＲ 序列,椎体扫描。结果：正常组在ＳＴＩＲ 序列椎体边缘骨髓呈高信号,中心呈低信号。增生性贫血可见椎体边缘高信号区明显扩大,但仍为正常分布。再障贫血骨髓信号明显减低,椎体边缘高信号消失,但有４ 例可见点状高信号残存。白血病骨髓信号增高且混杂,椎体中心也见高信号,失去正常分布。结论：ＭＲＩ 对小儿血液系统疾病骨髓改变的评价有意义。     

椎管内胚胎性肿瘤的MRI诊断

目的：评价ＭＲＩ对椎管内胚胎性肿瘤的诊断价值。材料与方法：经手术病理证实的椎管内胚胎性肿瘤共１５例，回顾性分析其ＭＲＩ表现。结果：（１）脂肪瘤（３例）具有特征性ＭＲＩ表现，Ｔ１ＷＩ呈高信号，Ｔ２ＷＩ呈中等高信号；通过脂肪抑制技术高信号转变为低信号。（２）皮样囊肿（２例）及表皮样囊肿（７例）好发于马尾及脊髓圆锥处，多发生于儿童，ＭＲＩ表现为Ｔ１ＷＩ低或等低及Ｔ２ＷＩ高或等高混杂密度影，病灶均有Ｔ１ＷＩ等信号包膜，两者ＭＲＩ不易鉴别。（３）畸胎瘤（３例）多位于骶尾部椎管内，ＭＲＩ可同时出现骨质信号、软组织信号及脂肪信号，亦可无骨质信号而单纯表现为软组织信号及脂肪信号。结论：椎管内胚胎性肿瘤诊断主要依据ＭＲＩ表现，结合发病部位和年龄特征可进一步提高诊断正确率。     

鼻咽癌放疗后放射性脑病的MRI诊断

作者观察了８４例鼻咽癌放疗后放射性脑病（ＲＥＰ）。其ＭＲＩ表现：病变主要位于双侧颞叶、脑干及小脑，Ｔ１ＷＩ病灶以低信号为（８１．３％），Ｔ２ＷＩ均为高信号，占位征象占２７．４％，萎缩征象占９．５％。还讨论了ＲＥＰ与脑梗塞、脑干胶质瘤及脑转移瘤的鉴别诊断。并提出了ＲＥＰ的ＭＲＩ分型，可分为颞叶型、脑干型、小脑型和混合型。作者还强调了ＭＲＩ显示ＲＥＰ，特别是显示脑干、小脑和颞叶底部的病灶，为ＣＴ及其他     

常见血液病的骨髓磁共振成像

磁共振成像(MRI)以其无创伤性、直接显示骨髓、检测异常骨髓的能力而成为评价骨髓病变的首选影像学检查方法。随着年龄的增长，正常人红骨髓按照一定规律转换为黄骨髓，MRI表现也发生相应的变化。多种原发血液病可引起骨髓MRI信号异常，甚至骨髓T1的变化。白血病骨髓典型表现为弥漫性的T1WI低信号，T1延长；白血病治疗后缓解，T1缩短接近正常范围。淋巴瘤及多发性骨髓瘤的MRI表现多种多样，取决于病变的恶性程度，但骨髓的T1均延长。再生障碍性贫血具有特征性的T1WI、T2WI高信号。增生性贫血由于红骨髓增生，黄骨髓逆转为红骨髓，贫血严重时甚至骨骺内的黄骨髓逆转为红骨髓。     

Ferumoxides-enhanced quantitative magnetic resonance imaging of the normal and abnormal bone marrow: preliminary assessment

The purpose of our study was to assess the effects of intravenous administration of ferumoxides on normal and abnormal vertebral bone marrow T1 and T2 relaxation times. Changes in bulk T1 and T2 relaxation times induced by intravenous administration of ferumoxides were determined in the normal vertebral marrow of two healthy subjects and four patients. In the four patients, changes in bulk T1 and T2 values induced by furomoxides injection were also determined in 12 vertebral metastases. Relative to precontrast relaxation time values, bulk T1 and T2 values of normal bone marrow had declined by a mean of 24% and 19%, respectively, in the two subjects and the four patients 45 minutes after ferumoxides administration. Relative to precontrast values, bulk T1 and T2 values of abnormal bone marrow had decreased by a mean of 16% and 2%, respectively. Decreases in bulk T1 and T2 values in normal bone marrow and in bulk T1 values in metastases were statistically significant (P<0.001). Changes in bulk T2 values observed in metastases were not statistically significant. Quantitative MRI demonstrates that ferumoxides infusion induces a decrease in bulk T1 and T2 relaxation times of normal bone marrow. It also suggests a lack of T2 shortening in bone metastases.     

正常股骨中下段骨髓MRI定量及1H-MRS研究

目的探讨正常股骨中下段骨髓磁共振成像（MRI）信号强度和氢质子磁共振波谱（^1H—MRS）随年龄增长的变化特点,为临床评价骨髓病变提供正常参考依据。资料与方法将70名2．30岁正常受检者按年龄分为6组：A组（2—5岁）9例,B组（6-10岁）10例,C组（11—15岁）10例,D组（16—20岁）13例,E组（21。25岁）13例,F组（26—30岁）15例。对股骨中下段分别采用矢状位SE T1WI和单体素激发回波序列（SVS-STEAM）进行MRI扫描和^1H-MRS采集。在T1WI上测量股骨干中段、下段和远侧干骺端骨髓及其相同水平相同层面邻近肌肉的信号强度,并计算各部位骨髓信号强度相对于肌肉的比值;同时分析3个相应股骨部位骨髓的^1H-MRS谱线。结果各年龄组中每一组内股骨干中段和下段骨髓信号强度之间差异无统计学意义（P〉0．05）,上述两个部位在B组与其他各任意年龄组间差异均有统计学意义（P〈0．05）,而在C-F组内任意两组间差异无统计学意义（P〉0．05）,15岁以前骨髓信号强度与年龄呈明显正相关,其后随年龄增长信号强度变化不显著。股骨远侧干骺端骨髓信号强度在c组与A—F组中的任一组之间差异均有统计学意义（P〈0．05）,但在AB两组间和D—F3组内差异无统计学意义（P〉0．05）,25岁以前骨髓信号强度与年龄呈明显正相关。股骨干中下段骨髓的^1H-MRS谱线在A组均为Lip1型,在B和C两组为Lip1型或Lip2型,在D—F组均为up2型。远侧干骺端骨髓的^1H-MRS谱线在所有年龄组为Lipl型,其中F组有up2型并存。结论不同年龄和不同股骨中下段骨髓的MRI信号强度和^1H-MRS的谱线不同,符合骨髓解剖生理学特点和骨髓转化规律,可作为股骨骨髓疾病分析的正常参考依据。     

Magnetic resonance relaxation characteristics of muscle, fat and bone marrow of the extremities. Normal values in a low field strength unit

The T1 and T2 relaxation times were calculated in the bone marrow, subcutaneous fat and muscles in the extremities of 21 volunteers. There were no significant differences in relation to age or sex. In the same individual, the difference in the relaxation time was negligible between different sites in muscle, fat and bone. These and other normal values reported are dependent on examination technique and calculation method which must be compensated for when comparisons between materials from different centers are performed.     

Magnetic resonance relaxation times of normal tissue in the course of chemotherapy: a study in patients with bone sarcoma

To study the effect of chemotherapy on normal fat, skeletal muscle, and bone marrow, T1 and T2 relaxation times were measured in 15 patients with bone sarcoma before and after each cycle of preoperative chemotherapy. A section plane containing the tumor and if possible the nonaffected extremity was imaged with combined multiecho spin echo and inversion recovery pulse sequences. T1 and T2 relaxation times were calculated in the normal-appearing tissues. Although some variation was found in the values in the individual patient and between patients, no systematic changes of relaxation times of fat, muscle, or bone marrow occurred in the course of treatment. We conclude that the chemotherapy used in bone sarcoma has no effect on relaxation times of normal fat, muscle, and bone marrow, and that therefore these tissues may serve as a reference for the signal intensity of tumor.     

In vivo measurements of the T1 relaxation processes in the bone marrow in patients with myelodysplastic syndrome. A magnetic resonance imaging study

Nine patients with myelodysplastic syndrome (MDS) were examined with magnetic resonance imaging and in vivo T1 relaxation time measurements of the vertebral bone marrow in a 1.5 tesla whole body scanner. Two patients underwent transformation to acute myeloid leukemia and were evaluated at follow-up examinations. At the time of diagnosis the T1 relaxation times of the vertebral bone marrow were significantly prolonged compared with normal values. The T1 relaxation times of the vertebral bone marrow in patients with MDS showed significantly lower values compared with patients with acute leukemia and did not differ from patients with polycythemia vera.     

Normal spinal bone marrow in adults: dynamic gadolinium-enhanced MR imaging

PURPOSE: To determine the patterns of dynamic enhancement of normal spinal bone marrow in adults at gadolinium-enhanced magnetic resonance (MR) imaging and the changes that occur with aging. MATERIALS AND METHODS: Dynamic contrast material-enhanced MR imaging of the thoracolumbar spine was performed in 71 patients. The maximum percentage of enhancement (Emax), enhancement slope, and enhancement washout were determined from bone marrow enhancement time curves (ETCs). The bone marrow signal intensity on T1-weighted spin-echo MR images was qualitatively classified into three grade categories. Quantitative ETC values were correlated with patient age and bone marrow fat content grade. Statistical analysis included mean t test comparison, analysis of variance, and regression analysis of the correlations between age and quantitative MR parameters. RESULTS: Emax, slope, and washout varied widely among the patients. Emax values were obtained within 1 minute after contrast material injection and ranged from 0% to 430%. Emax values were significantly higher in patients younger than 40 years than in those aged 40 years or older (P <.001). These values decreased with increasing age in a logarithmic relationship (r = 0.71). Emax values decreased as fat content increased, but some overlap among the fat content grades was noted. Analysis of variance revealed that Emax was significantly related to age (younger than 40 years vs 40 years or older) (P <.001) and fat content grade (P <.001) but not significantly related to sex. CONCLUSION: Dynamic contrast-enhanced MR imaging patterns of normal spinal bone marrow are dependent mainly on patient age and fat content.     

Bone marrow: ultrasmall superparamagnetic iron oxide for MR imaging

An ultrasmall superparamagnetic iron oxide (USPIO) preparation was evaluated as a potential intravenous contrast agent for magnetic resonance (MR) imaging of bone marrow. One hour after administration of USPIO (40, 80, and 160 mumols of iron per kilogram body weight) in rats and rabbits, T1 and T2 relaxation times were, respectively, approximately 30%, 50%, and 65% lower than precontrast relaxation times. Maximum decrease in relaxation times of marrow occurred within 1-24 hours after intravenous administration; thereafter, relaxation times slowly returned to normal within 7 days. In vivo MR imaging of rabbits and rats confirmed that USPIO decreases signal intensity of red and yellow marrow. The decrease was most marked with gradient echo pulse sequences. An animal model of intramedullary tumor demonstrated the potential of USPIO to enable differentiation between tumor and normal red marrow. USPIO-enhanced MR imaging improves detection of smaller tumors and allows differentiation of tumor deposits from islands of hyperplastic or normal red marrow.     

Repopulation of marrow after transplantation: MR imaging with pathologic correlation

Sixty-seven magnetic resonance (MR) studies of the lumbar spine were performed in 15 patients with bone marrow transplants, and the appearance of marrow regeneration on MR images was correlated with results of bone marrow biopsy and pathologic examination. After transplantation, T1-weighted MR images of vertebral marrow showed a characteristic band pattern consisting of a peripheral zone of intermediate signal intensity and a central zone of bright signal intensity. Reciprocal changes were identified on short inversion time inversion recovery images. At histologic examination the central zone corresponded to fatty marrow; the peripheral zone corresponded to a zone of regenerating hematopoietic cells. Posttransplantation T1 and T2 relaxation times of the entire vertebral marrow were calculated from the spin-echo images; no statistically significant trends in relaxation times were noted. Knowledge of the normal MR pattern of marrow regeneration after transplantation may be useful in screening for residual marrow disease, determining marrow engraftment, and differentiating marrow repopulation with normal versus malignant cells.     

99Tcm-MDP骨显像观察骨水泥阻塞兔骨干髓腔后远侧骨血流和代谢

目的 用^99Tc^m-亚甲基二膦酸盐（MDP）显像观察骨水泥阻塞兔股骨近中段骨干髓腔对其股骨远端骨血流和代谢的近、远期影响.方法 兔左侧后肢股骨髓腔内灌注聚甲基丙烯酸甲酯TJ骨水泥（PMMA）,而右侧不灌注作为正常对照,制作骨水泥阻塞股骨近中段骨干髓腔的兔模型.将24只实验兔根据不同的观察时间段随机分成术后当天（T0）、术后4周（T4）、术后8周（T8）、术后16周（T16）4组,每组6只.对模型兔双侧后肢股骨行动态（血流相）和静态（骨相）显像,选取双侧后肢股骨远端相同的感兴趣区（ROI）,算出实验侧/对照侧放射性比值,并进行比较.结果 T0、T4组实验侧放射性计数均比对照侧明显降低,T8、T16组实验侧放射性计数均超过对照侧,T16组最高;实验侧/对照侧各时间段放射性比值比较：T0与T8、T0与T16、T4与T16、T8与T16、T4与T8组间差异均有显著性（P均＜0.05）,而T0与T4组间差异无显著性（P＞0.05）.骨动态显像和静态显像的变化趋势完全一致.结论 骨水泥阻塞股骨近中段骨干髓腔后严重破坏了骨内和髓内的血液循环状态,引起局部血流动力学改变,导致股骨远端的血供和代谢状况发生变化.