脊柱良恶性压缩骨折的MR波谱分析

目的探讨骨质疏松和恶性肿瘤所致脊柱良恶性压缩骨折的MR氢质子波谱(1HMRS)特征。方法对37例骨质疏松和21例恶性肿瘤所致椎体压缩性骨折病例进行1H MRS采集,同时以30例健康志愿者L2椎体的1H MRS作对照,定量分析感兴趣椎体的脂肪百分含量(FF%)及脂与水的比率(LWR)。结果对照组L2椎体平均脂肪含量为(45.0±20.2)%,平均LWR为0.76;骨质疏松组病变椎体的平均脂肪含量(67.0±14.3)%,平均LWR为1.75;恶性肿瘤组病变椎体平均脂肪含量(1.8±1.2)%;平均LWR为0.1。骨质疏松组FF%和LWR明显高于恶性肿瘤组(t=2.87,P<0.01),亦较高于正常对照组(t=2.06,P<0.05);恶性肿瘤组FF%和LWR明显低于正常对照组(t=2.75,P<0.01)。结论1H MRS能无创性检测脊柱椎体的脂肪含量及LWR,脊柱良恶性压缩椎体的脂肪含量及LWR差异有统计学意义,有助于骨质疏松和恶性肿瘤所致椎体压缩性骨折的鉴别诊断。     

Value of opposed-phase gradient-echo technique in distinguishing between benign and malignant vertebral lesions

Our objective was to evaluate the possible role of opposed-phase gradient-echo (GRE) sequence in predicting the nature of vertebral lesions supposing that in the case of malignancy fat is completely replaced while in the case of benign lesion fat is still present. Eighty-six patients with vertebral lesions underwent MR examination at 0.5 T. The MR protocol included a T1-weighted spin-echo (SE) and an opposed-phase GRE using the same parameters (TR=280-320 ms, flip angle=90 degrees, slice thickness=3.5-4 mm, matrix=256x160-192, field of view=34-36 cm, no. of excitations=2-4) except for TE (10 ms in SE vs 7 ms in GRE) to obtain opposed-phased images. Qualitative (nature of lesion, detectability, degree of signal intensity (SI), marrow pattern) and quantitative (SI on opposed-phase GRE minus SI on T1-weighted SE minus SI ratio=SI on out-of-phase GRE images divided by SI on T1-weighted SE images) analysis were performed. The SI ratio values were analysed using Mann-Whitney rank-sum test and receiver operating characteristics (ROC) curve. Lesions resulted to be malignant in 45 and benign in 41 patients (23 biopsies, 20 MR follow-ups, 43 clinical and other imaging follow-ups). Based on visual inspection of opposed-phased images, visual SI was evaluated high in 38 (34 malignant, 34 benign), mild in 28 (9 malignant, 19 benign) and low in 20 (2 malignant, 18 benign) patients. Based on region-of-interest measurements, SI ratio values range was 0.36-6.2 (mean value=1.68+/-0.82) for malignant and 0.07-1.54 (mean value=0.77+/-0.44) for benign lesions. A cut-off value of 1.2 gave a sensitivity, specificity, accuracy, negative predictive value and positive predictive value, respectively, of 88.8, 80.49, 84.88, 86.4 and 83.33%. The ROC analysis of the SI ratio showed an area under ROC curve of 0.92 and a statistically significant difference between the two groups of lesions was observed ( p<0.01). The GRE opposed-phase sequence can help to predict the nature of a vertebral lesion. This fast and widely available technique together with morphological criteria can improve the accuracy of MRI.     

Use of FDG-PET in differentiating benign from malignant compression fractures

Objective The objective was to evaluate the use of fluorodeoxyglucose positron emission tomography (FDG-PET) in differentiating benign from malignant compression fractures. Patients and methods In a retrospective analysis, we identified 33 patients with 43 compression fractures who underwent FDG-PET. On FDG-PET the uptake pattern was recorded qualitatively and semiquantitatively and fractures were categorized as benign or malignant. Standardized uptake values (SUV) were obtained. MRI, CT, and biopsy results as well as clinical follow-up for 1–3 years served as standards of reference. The Student’s t test was used to determine whether there was a statistically significant difference between the SUV for benign and malignant compression fractures. Results There were 14 malignant and 29 benign compression fractures, including 5 acute benign fractures. On FDG-PET, 5 benign fractures were falsely classified as malignant (false-positive). Three of these patients underwent prior treatment with bone marrow-stimulating agents. There were two false-negative results. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of FDG-PET in differentiating benign from malignant compression fractures were 86%, 83%, 84%, 71%, and 92% respectively. The difference between SUV values of benign and malignant fractures was statistically significant (1.9 ± 0.97 for benign and 3.9 ± 1.52 for malignant fractures, p < 0.001). SUV of benign acute and chronic fractures were not statistically significant. Conclusion Fluorodeoxyglucose positron emission tomography is useful in differentiating benign from malignant compression fractures. Therapy with bone marrow-stimulating agents can mimic malignant involvement.     

MR imaging of edema accompanying benign and malignant bone tumors

To evaluate the incidence, quantity, and presentation of intra- and extraosseous edema accompanying benign and malignant primary bone lesions, the magnetic resonance (MR) studies of 63 consecutive patients with histologically proven primary bone tumors were reviewed. MR scans were assessed for the presence and quantity of marrow and soft tissue edema and correlated with peroperative findings, resected specimens and follow-up data. The signal intensity and enhancement of tumor and edema prior to and after intravenous administration (if any) of gadolinium-labled diethylene triamine pentaacetate (Gd-DTPA) was analyzed. Marrow edema was encountered adjacent to 8 of 39 malignant tumors and 14 of 24 benign lesions. Soft tissue edema was found accompanying 28 of 39 malignancies and 10 of 24 benign disorders. On unenhanced T1-weighted MR images tumor and edema were difficult to differentiate. Tumor inhomogeneity made this differentiation easier on T2-weighted sequences. In 36 patients the contrast medium Gd-DTPA was used. Edema was present in 27 of these patients and the respective enhancement of tumor and edema could be compared. Edema always enhanced homogeneously, and in most cases it enhanced to a similar degree as or more than tumor. Marrow and, more specifically, soft tissue edema is a frequent finding adjacent to primary bone tumors. The mere presence and quantity of marrow and soft tissue edema are unreliable indicators of the biologic potential of a lesion. Unenhanced MR scans cannot always differentiate between tumor and edema, but the administration of Gd-DTPA is of assistance in differentiating tumor from edema. Awareness of marrow and/or soft tissue edema adjacent to bone lesions is of importance because edema can be a pitfall in the diagnostic work-up and staging prior to biopsy or surgery.     

Differentiation of acute osteoporotic from malignant vertebral compression fractures with conventional MRI and diffusion MR imaging

Aim

To evaluate the role of using a single shot spin echoplanar DW sequence (SSSEP-DWI) compared to conventional MRI and contrast enhanced T1WI in differentiation between vertebral osteoporotic fractures and malignant compression fractures. The sensitivity and specificity of (SSSEP-DWI) will also be calculated.

对良、恶性椎体压缩性骨折MRI鉴别诊断的再认识

目的：提高对椎体压缩性骨折定性征象的认识。方法：回顾性分析经临床确诊的椎体压缩性骨折56例78个椎体，外伤性骨折11例15个椎体；非外伤性骨折17例25个椎体；恶性压缩性骨折28例38个椎体，MRl分别重点观察了椎体骨髓信号、椎体后缘的形态、MRI增强的强化方式、椎弓根的形态及椎旁软组织的形态。结果：恶性压缩性骨折较特异性的MRI征象有：(1)L1WI像上椎体呈广泛均匀低信号；(2)椎体后缘呈球形凸出；(3)T2WI像上椎弓根膨大且可见高信号；(4)T2WI／I像受累椎体的不均一强化；(5)瘤样椎旁软组织肿块。结论：MRI的特征性改变能准确地鉴别良、恶性椎体压缩性骨折。     

Malignant and benign compression fractures: differentiation and diagnostic pitfalls on MRI

The distinction between malignant and benign compression fractures is a common problem in clinical practice. Various imaging techniques (plain radiography, computed tomography, bone scintigraphy) have been used to differentiate these conditions but they are often inadequate in distinguishing the nature of compression fracture. This review illustrates the magnetic resonance imaging (MRI) features of malignant and benign compression fractures with emphasis on the usefulness, limitations and pitfalls of MRI.     

Greater trochanter fractures: MR assessment and its influence on patient management

Eight patients with nondisplaced greater trochanteric (GT) fractures diagnosed by conventional radiographs were evaluated with magnetic resonance (MR) imaging. MR imaging demonstrated unsuspected intertrochanteric (IT) extension in each of the eight patients. This resulted in unanticipated surgical intervention in six of eight patients. Nondisplaced GT fractures are often more extensive and complex than they appear on conventional radiographs. MR imaging is useful in determining the extent and morphology of these fractures, information valuable for orthopedic management, and should be considered for definitive assessment in these patients.     

Missed incidental vertebral compression fractures on computed tomography imaging: More optimism justified

Missed incidental vertebral compression fractures on computed tomography (CT) imaging are a common problem. Although numerous publications are available on this topic, recent publications still show a high percentage of such missed fractures. The rate of such missed fractures in the authors department is much lower than that in the reported literature when routine multiplanar reconstructions are used for reporting CT scans. Therefore, a more optimistic view on this topic seems to be justified.     

Cervical spine fractures in ankylosing spondylitis: MR findings

Purpose: The purpose of this study is to evaluate the MR findings in patients with long-term ankylosing spondylitis (AS) and acute cervical spine fractures. Materials and methods: The magnetic resonance imaging (MRI) studies of five patients with AS and acute cervical spine fractures were retrospectively reviewed for the presence of cervical spine instability, spinal cord compression, and epidural hematoma. Results: Spinal fractures were unstable in all five patients. Three patients had neurological symptoms and abnormal signal within the spinal cord. All patients with neurological deficits had epidural hematomas posterior to the dural sac. Conclusion: MRI is useful for assessment of the integrity of intervertebral disks and spinal ligaments and, therefore, of the instability of the spinal fracture. MRI is mandatory in patients with neurological symptoms, especially in those with a symptom-free interval and those with neurological deterioration after established spinal cord injury, when suspicion for epidural hematoma is high. Electronic Publication     

Incidental vertebral compression fractures in imaging studies: Lessons not learned by radiologists

AIM: To assess radiologists reporting rates of incidental vertebral compression fractures in imaging studies.METHODS: We performed a review of the current literature on the prevalence and reporting rates of incidental vertebral compression fractures in radiologic examinations.RESULTS: The bibliographic search revealed 12 studies: 7 studies using conventional radiology and 5 using multidetector computed tomography (MDCT). The loss of height cut-off to define a vertebral fracture varied from 15% to 25%. Fracture prevalence was high (mean 21.1%; range 9.5%-35%) in both radiographic and MDCT studies (mean 21.6% and 20.2%, respectively). Reporting rates were low with a mean value of 27.4% (range 0%-66.3%) and were significantly lower in MDCT than in radiographic studies (mean 8.1% vs 41.1%). Notably, recent studies showed lower reporting rates than older studies.CONCLUSION: Many scientific studies have confirmed a high prevalence of vertebral compression fractures as incidental findings on imaging studies. However, the underreporting of these fractures, as determined in our study, may negatively affect patient care.     

Characterization of benign and metastatic vertebral compression fractures with quantitative diffusion MR imaging

BACKGROUND AND PURPOSE: Conventional imaging techniques cannot be used to unambiguously and reliably differentiate malignant from benign vertebral compression fractures. Our hypothesis is that these malignant and benign vertebral lesions can be better distinguished on the basis of tissue apparent diffusion coefficients (ADCs). The purpose of this study was to test this hypothesis by using a quantitative diffusion imaging technique. METHODS: Twenty-seven patients with known cancer and suspected metastatic vertebral lesions underwent 1.5-T conventional T1-weighted, T2-weighted, and contrast-enhanced T1-weighted imaging to identify the lesions. Diffusion-weighted images of the areas of interest were acquired by using a fast spin-echo diffusion pulse sequence with b values of 0-250 s/mm(2). The abnormal regions on the diffusion-weighted images were outlined by using the conventional images as guides, and the ADC values were calculated. On the basis of pathologic results and clinical findings, the cases were divided into two categories: benign compression fractures and metastatic lesions. The ADC values for each category were combined and plotted as histograms; this procedure was followed by statistical analysis. RESULTS: The patient group had 12 benign fractures and 15 metastases. The mean ADC values, as obtained from the histograms, were (1.9 +/- 0.3) x 10(-4) mm(2)/s and (3.2 +/- 0.5) x 10(-4) mm(2)/s for metastases and benign fractures, respectively. CONCLUSION: Our results indicate that quantitative ADC mapping, instead of qualitative diffusion-weighted imaging, can provide valuable information in differentiating benign vertebral fractures from metastatic lesions.     

微创治疗陈旧性老年骨质疏松性椎体压缩骨折

目的探讨应用微创球囊扩张椎体成形术(PKP)治疗陈旧性老年骨质疏松性椎体压缩性骨折的可行性. 方法 2007年2月-2009年2月收治以胸背或者腰背部疼痛为主并且无明显神经损伤的老年陈旧性骨质疏松性椎体压缩骨折27例,其中男11例,女16例;年龄55～86岁,平均72.4岁.病史3～17个月,平均7.6个月.其中单阶段病变25例,双阶段病变2例.Genant二级10例,11个椎体;Genant三级17例,18个椎体.术前模拟视觉疼痛评分(VAS)平均8.3分,X线测量椎体前高与后高比平均为39%,脊柱后凸角测量平均27.60°.所有患者均在局部麻醉下行PKP治疗. 结果 术后所有患者疼痛消失或明显减轻,第3或4天能够下地活动.平均随访11.2个月,所有患者疼痛无反复,心肺功能有明显改善,无严重并发症发生;术后VAS平均2.8分,X线测量椎体前高与后高比平均为47.6%,脊柱后凸角测量术后平均15.60°. 结论应用微创PKP治疗以疼痛为主且不伴有神经损伤的老年陈旧性骨质疏松性椎体压缩骨折能够尽快去除疼痛,尽快使患者下床活动,减少长期卧床的并发症,改善心肺功能.     

Optimization of b value in diffusion-weighted MRI for the differential diagnosis of benign and malignant vertebral fractures

Objective The objective was to explore the optimal b value in diffusion-weighted imaging (DWI) of MRI for differential diagnosis of benign and malignant vertebral fractures. Materials and Methods Thirty-four consecutive patients with vertebral compression fractures underwent sagittal diffusion-weighted imaging (DWI) with different b values. The group included 14 patients with 18 benign vertebral fractures due to osteoporosis and/or trauma and 20 patients with 27 malignant vertebral fractures due to malignancy. The quality of the images was analyzed qualitatively on a three-point scale and quantitatively by measurement of the signal-to-noise ratio (SNR). Apparent diffusion coefficient (ADC) values were also calculated. Results Smaller b values correlated with better DW image quality. We found significant differences in the qualitative points values among the DW images with different b values (F = 302.18, p < 0.001). The mean SNR of the images ranged from 21.75 ± 3.64 at a b value of 0 s/mm² to 5.31 ± 3.17 at a b value of 800 s/mm². The SNR of DWI with a b value of 300 s/mm² (18.62 ± 2.47) was significantly different from that with other b values (p < 0.01). The mean combined ADC values of malignant fractures were significantly lower than those of benign ones on DWI with a b value of 300 s/mm² (t = 9.097, p < 0.01). Four cases of benign vertebral fractures were misdiagnosed as being malignant when b values of 0 s/mm² and 100 s/mm² were used. Conclusions When DWI with multiple b values is used to differentiate benign from malignant vertebral compression fractures, b values within the range of around 300 s/mm² are recommended, taking into account both SNR and diffusion weighting of water molecules.     

经皮椎体成形术及后凸成形术治疗骨质疏松性椎体压缩骨折的临床对比研究

目的 探讨和比较经皮椎体成形术（percutaneous vertebroplasty,PVP）和后凸成形术（percutaneous kyphoplasty,PKP）治疗骨质疏松性椎体压缩骨折(osteoporotic vertebral compression fractures,OVCFs)的疗效、安全性和效价比。方法 回顾性分析72例（共96椎）经PVP（34例）和PKP( 38例)治疗的OVCFs患者的临床病历资料,并进行比较。72例患者均在C形臂机透视导向下经皮穿刺椎弓根到病变椎体,然后,PVP组在病变处直接注入骨水泥;PKP组在病变部位置入球囊进行扩张后注入骨水泥。记录手术透视时间、每椎骨水泥注射量和治疗费用（手术费+耗材费）。统计手术前和手术后24h、1周、1个月疼痛视觉模拟评分(visual analogue scale,VAS),以及手术前后椎体前缘和中部高度、Cobb角矫正情况,观察术后症状改善、并发症发生情况。结果 中计量资料2组间的比较采用t检验,多组资料的比较采用方差分析;计数资料采用x2检验。结果 所有患者的治疗操作均顺利并成功,术后随访1.0～34.0个月,平均(8.9±3.2)个月。(1)PVP组平均手术透视时间为(11.1±10.6) min/椎,PKP为(23.5±13.0) min/椎,两者差异有统计学意义(P ＜0.05)。(2) PVP组平均治疗费用为（5127.2±502.3）元/例,PKP为(32 301.4±3204.6)元/例,两者差异有统计学意义(P＜0.05)。(3)PVP组平均每椎骨水泥注射量为(4.9±1.1)ml,PKP为(5.4±1.7)ml,两者差异无统计学意义(P＞0.05)。(4)术后24h疼痛缓解率PVP组为94.1％( 32/34)、PKP组为92.1％(35/38),两者差异无统计学意义(P＞0.05)。PKP组VAS评分术前,术后24h、1周、1个月分别为(8.3±0.4)、(2.9±0.9)、(2.6±0.9)、(2.6±0.9)分,术前和术后各时间点比较差异均有统计学意义（P值均＜0.05）;PVP组VAS评分术前,术后24h、1周、1个月分别为（7.9±0.8）、(2.8±1.2)、(2.6±1.1)、(2.5±1.3)分,术前和术后各时间点比较差异均有统计学意义（P值均＜0.05）;而PVP和PKP两种手术方法间比较差异无统计学意义(P＞0.05)。(5) PVP组术前椎体前缘、中部高度及Cobb角分别为(19.1±1.4) nun、(25.2±1.0) mm、(24.2±3.8)°,术后分别为(21.0±1.5) mm、(27.0±1.2) mm、(19.4±3.9)°,术前和术后比较差异均有统计学意义（P值均＜0.05）;PKP组术前椎体前缘、中部高度及Cobb角分别为(19.5±1.5)mm、(25.4±1.1) mm、(25.1±5.0)°,术后分别为(24.3±1.9) mm、(29.7±1.3) mm、(10.7±2.8)°,术后和术前比较差异均有统计学意义（P值均＜0.05）;PKP组矫正效果优于PVP组,两者差异有统计学意义（P值均＜0.05）。(6)PVP组9例椎骨发生水泥渗漏,PKP组3例椎骨发生水泥渗漏,两者差异有统计学意义(P＜0.05)。所有骨水泥渗漏均未引起临床症状。(7)所有经治患者未发现其他严重并发症。结论 PVP和PKP治疗OVCFs 效果良好、安全,但PVP效价比优于PKP。     

Quantitation of structural distortion of the cervical neural foramina in gradient-echo MR imaging

Quantitative errors (due to magnetic susceptibility artifacts) in the measurement of the cervical spinal neural foramina with fast gradient-echo (GRE) magnetic resonance imaging were assessed. Cylindric phantoms of different materials were used to demonstrate the nature of magnetic susceptibility artifacts, emphasizing the dependence of the artifact on tissue geometry. Neural foramina diameters measured on thin, sagittal GRE and spin-echo (SE) images through the neural foramina of a fresh human cervical spine specimen were then compared with direct measurements with calipers. The GRE images showed more apparent narrowing than did the SE images. The absolute distortion of seven neural foramina was rather constant (less than two pixels) on the GRE images; therefore, the relative distortion was inversely proportional to the size of the neural foramen, ranging up to 10% in the upper cervical region at a short TE. The absolute and relative distortion increased as TE increased. At a constant TE, the structural distortion did not change with different TRs or flip angles. The shortest possible TE is recommended in evaluation of the cervical spine.     

Normal and degenerating articular cartilage: in vitro correlation of MR imaging and histologic findings.

Histologic correlation of the different magnetic resonance (MR) appearances of articular cartilage has not been studied extensively. Therefore, the authors correlated thin (high-resolution) MR sections of articular cartilage with histologic sections. Human cadaver lumbar facet joints were imaged with a 1-mm section thickness and a 4-cm field of view, then sectioned and stained for histologic comparison. MR imaging patterns were identified that correlated with normal cartilage and three histologically different patterns of degeneration.     

MR imaging of supra-acetabular insufficiency fractures

 Objective. Diagnosis of insufficiency fractures in the pelvis is difficult, especially in patients with prior malignancy, irradiation, steroid therapy or osteoporosis. This report shows the MR imaging appearance of supra-acetabular insufficiency fractures and how they can be differentiated from metastatic disease. Design and patients. Twelve patients (four men, eight women, average age 72.8 years) at risk for pelvic insufficiency fractures and who had pelvic or hip pain were studied with MR imaging. Indications were possible recurrent tumor or previous radiation to the pelvis (7 patients); osteoporosis from steroid use in rheumatoid arthritis (two patients); to exclude osteonecrosis of the hip (two patients); or to rule out a hip fracture (one patient). Results. A characteristic linear region of low signal intensity on both T1- and T2-weighted sequences was found in the supra-acetabular region paralleling the superior acetabulum in a curvilinear arc in 92% (11/12) of cases, and oblique in origin in 8% (1/11). Diffuse bands of high signal on T2-weighted images indicated surrounding edema. In two cases, MR findings obviated biopsy. One patient underwent a biopsy prior to the imaging studies being reviewed. All patients were treated conservatively and did well. Discussion. Attention to insufficiency fractures has previously focused on characteristic locations in the sacrum and pubic bones. Supra-acetabular insufficiency fractures also occur and are difficult to diagnose without a high degree of suspicion. MR imaging is a useful tool for diagnosing supra-acetabular insufficiency fractures. The characteristic MR imag-ing appearance of these fractures can preclude additional diagnostic studies and therapy in most instances.     

经皮椎体成形术治疗骨质疏松性椎体骨折疗效观察

目的探讨经皮椎体成形术治疗骨质疏松性椎体压缩性骨折的临床疗效及应用价值。方法36例骨质疏松性压缩性骨折患者45个椎体，在C型臂X线透视下，取俯卧位，经皮穿刺，在病椎注入聚甲基丙烯酸甲酯。术前及术后3d进行疼痛视觉类比评分（VAS评分），并进行统计学分析。结果治疗后36例患者疼痛较治疗前有明显好转，VAS评分差异有统计学意义（P〈0．001）；活动能力也有不同程度改善；部分椎体的前缘和椎体中部高度有一定恢复。结论经皮椎体成形术治疗骨质疏松性椎体压缩骨折止痛效果明显，能很快改善患者的活动能力，早期下床活动。该手术属微创手术，在骨科临床有一定的应用前景。     

Vertebral compression fractures: distinction between benign and malignant causes with MR imaging

Magnetic resonance (MR) imaging was performed on 64 patients with 109 vertebral compression fractures, the cause of which could not be determined from plain radiographs. Twenty-five fractures were due to malignancy; 84 were caused by a benign process. In 22 of the 25 fractures caused by malignancy, MR images showed complete replacement of normal bone marrow, whereas 47 of the 61 benign fractures without history of trauma had complete preservation of normal bone marrow. The remaining 14 benign fractures had incompletely preserved bone marrow in a regular pattern. In two of the three remaining malignant fractures, the bone marrow replacement also was incomplete but with an irregular pattern. In cases of recent trauma or primary bone marrow abnormalities, the configuration and signal of remaining bone marrow were not useful in differentiating among malignancy, osteoporosis, and other benign processes. When criteria based on complete loss or preservation of marrow and marrow configuration in cases of incomplete loss were used, the accuracy in differentiating benign from malignant fractures was 94%. MR imaging may be a useful adjunct in differentiating benign from metastatic fractures and may provide information not available with other imaging methods.