Diagnostic value of apparent diffusion coefficient to differentiate benign from malignant vertebral bone marrow lesions

Background

Vertebral collapse is a common problem due to benign bone marrow lesions, trauma or malignant process. The diagnosis is often correctly predicted from characteristic imaging appearance. Some vertebral collapses have atypical imaging appearance that may cause diagnostic confusion.

Aim

To evaluate the value of the ADC obtained in DW-MR sequences for the differentiation between benign and malignant bone marrow lesions.

Patients

Sixty patients were included in this study, referred from Neurosurgery and Radiotherapy Departments and proved to have vertebral compression based on conventional MR imaging.

Results

The ADC value resulted in statistically significant characterization between (osteoporotic and post-traumatic collapse) and (malignant vertebral collapse) (P < 0.0001) while there was no statistically significant findings between infective spondylodiscitis and malignant vertebral collapse (P > 0.05). The sensitivity, specificity, PPV, NPD of DWI and ADC values in differentiating benign from malignant vertebral collapse were 100%, 83.3%, 60% and 100% respectively.

Conclusions

ADC values are a useful complementary MRI tool to characterize bone marrow lesions, in order to distinguish acute benign fractures from malignant or infectious bone marrow lesions. However, ADC values are not valuable in order to differentiate malignancy from infection with diagnostic overlap in the subacute traumatic vertebral collapse.     

Repeatability and reproducibility of apparent diffusion coefficient and fat fraction measurement of focal myeloma lesions on whole body magnetic resonance imaging

Objective:To assess intra- and inter-reader variability of apparent diffusion coefficient (ADC) and fat fraction (FF) measurement in focal myeloma bone lesions and the influence of lesion size.Methods:22 myeloma patients with focal active disease on whole body MRI were included. Two readers outlined a small (5–10 mm) and large lesion (>10 mm) in each subject on derived ADC and FF maps; one reader performed this twice. Intra- and inter-reader agreement for small and large lesion groups were calculated for derived statistics from each map using within-subject standard deviation, coefficient of variation, interclass correlation coefficient measures, and visualized with Bland–Altman plots.Results:For mean ADC, intra- and inter-reader repeatability demonstrated equivalently low coefficient of variation (3.0–3.6%) and excellent interclass correlation coefficient (0.975–0.982) for both small and large lesions. For mean FF, intra- and inter-reader repeatability was significantly poorer for small lesions compared to large lesions (intra-reader within-subject standard variation estimate is 2.7 times higher for small lesions than large lesions (p = 0.0071), and for inter-reader variations is 3.8 times higher (p = 0.0070)).Conclusion:There is excellent intra- and inter-reader agreement for mean ADC estimates, even for lesions as small as 5 mm. For FF measurements, there is a significant increase in coefficient of variation for smaller lesions, suggesting lesions >10 mm should be selected for lesion FF measurement.Advances in knowledge:ADC measurements of focal myeloma have excellent intra- and inter-reader agreement. FF measurements are more susceptible to lesion size as intra- and inter-reader agreement is significantly impaired in lesions less than 10 mm.     

Relationship between bone marrow cellularity and apparent diffusion coefficient

This study was performed to determine if there is a relationship between apparent diffusion coefficient (ADC) and cellularity of bone marrow of the posterior ilium. Four groups of various marrow cellularity underwent diffusion-weighted echo-planar imaging: 1) adults with normal hypocellularity (21 patients); 2) adults with normal normocellularity (13 patients); 3) young children with normal hypercellularity (5 patients); and 4) adults with lymphoma-related hypercellularity (3 patients). In all adults, marrow cellularity was confirmed by uni-or bilateral bone marrow biopsies. In children, the iliac marrow was presumed hypercellular because of their ages. A total of 66 ADC values of bone marrow calculated from diffusion-weighted images with b-values of 30 and 300 seconds/mm(2) was evaluated. Hypercellular marrow (normal and lymphoma-related) showed the highest mean ADC, and hypocellular the lowest ADC. Statistically significant differences were found between three groups of normal marrow: hypocellular, normocellular, and hypercellular. There is a positive correlation between ADC and cellularity of bone marrow. J. Magn. Reson. Imaging 2001;13:757-760.     

Diagnostic value of apparent diffusion coefficients to differentiate benign from malignant vertebral bone marrow lesions

Aim

The aim of this study is to evaluate the value of the apparent diffusion coefficient (ADC) obtained in diffusion-weighted (DW) MR sequences for the differentiation between malignant and benign bone marrow lesions.

Method

Forty-five patients with altered signal intensity vertebral bodies on conventional MR sequences were included. The cause of altered signal intensity was benign osteoporotic collapse in 16, acute neoplastic infiltration in 15, and infectious processes in 14; based on plain-film, CT, bone scintigraphy, conventional MR studies, biopsy or follow-up. All patients underwent isotropic DW MR images (multi-shot EPI, b values of 0 and 500 s/mm²). Signal intensity at DW MR images was evaluated and ADC values were calculated and compared between malignancy, benign edema and infectious spondylitis.

Results

Acute malignant fractures were hyperintense compared to normal vertebral bodies on the diffusion-weighted sequence, except in one patient with sclerotic metastases. Mean ADC value from benign edema (1.9 ± 0.39 × 10⁻³ mm²/s) was significantly (p < 0.0001) higher than untreated metastasic lesions (0.9 ± 1.3 × 10⁻³ mm²/s). Mean ADC value of infectious spondilytis (0.96 ± 0.49 × 10⁻³ mm²/s) was not statistically (p > 0.05) different from untreated metastasic lesions. ADC value was low (0.75 × 10⁻³ mm²/s) in one case of subacute benign fracture.

Conclusions

ADC values are a useful complementary tool to characterize bone marrow lesions, in order to distinguish acute benign fractures from malignant or infectious bone lesions. However, ADC values are not valuable in order to differentiate malignancy from infection.     

Apparent diffusion coefficient and fractional anisotropy in the vertebral bone marrow

Purpose:

To assess the state of cancellous tissue we analyzed the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in vertebral bone marrow.

Materials and Methods:

With 1.5 T magnetic resonance imaging (MRI), single‐shot diffusion echo planar imaging was used with b factors of 0 and 1000 s/mm², diffusion‐sensitizing gradient in six directions, sensitivity encoding technique, effective TE of 74 msec, and TR of 1800 msec. ADC and FA were determined in the lumbar vertebral body of 11 normal subjects (age 31 632–635 years), and then compared with the bone mineral density (BMD) obtained with dual‐energy x‐ray absorptiometry (DXA). Moreover, fat fraction (FF) of the bone marrow was measured with spectral presaturation with inversion recovery (SPIR) in the same subject.

Results:

A strong negative correlation was found between ADC and BMD for low or moderate FF in vertebral bone marrow. Moreover, a significant positive correlation was noted between ADC and FF in this region. There was a positive correlation between FA and BMD, and no correlation between FA and FF in the vertebral bone marrow.

Conclusion:

Diffusion analyses with ADC and FA make it possible to obtain more detailed information on the structure of cancellous tissue and bone metabolism. J. Magn. Reson. Imaging 2010;31:632–635. © 2010 Wiley‐Liss, Inc.     

Proton-density fat fraction and simultaneous R2* estimation as an MRI tool for assessment of osteoporosis

Objective

To investigate multi-echo chemical shift-encoded MRI-based mapping of proton density fat fraction (PDFF) and fat-corrected R2* in bone marrow as biomarkers for osteoporosis assessment.

Methods

Fifty-one patients (28 female; mean age 69.7?±?9.0 years) underwent dual energy X-ray absorptiometry (DXA). On the basis of the t score, 173 valid vertebrae bodies were divided into three groups (healthy, osteopenic and osteoporotic). Three echo chemical shift-encoded MRI sequences were acquired at 3 T. PDFF and R2* with correction for multiple-peak fat (R2*MP) were measured for each vertebral body. Kruskal–Wallis test and post hoc analysis were performed to evaluate differences between groups. Further, the area under the curve (AUC) for each technique was calculated using logistic regression analysis.

Results

On the basis of DXA, 92 samples were normal (53 %), 47 osteopenic (27 %) and 34 osteoporotic (20 %). PDFF was increased in osteoporosis compared with healthy (P?=?0.007). R2*MP showed significant differences between normal and osteopenia (P?=?0.004), and between normal and osteoporosis (P?<?0.001). AUC to differentiate between normal and osteoporosis was 0.698 for R2*MP, 0.656 for PDFF and 0.74 for both combined.

Conclusion

PDFF and R2*MP are moderate biomarkers for osteoporosis. PDFF and R2*MP combination might improve the prediction in differentiating healthy subjects from those with osteoporosis.

Key Points

? Magnetic resonance imaging offers new insights into bone composition. ? PDFF and R2* are moderate biomarkers for the assessment of osteoporosis. ? R2* mapping for staging of osteoporosis is affected by bone marrow fat. ? Multi-peak spectral modelling improved the relationship between osteoporosis and R2*. ? PDFF/multi-peak fat-corrected R2* together might improve differentiation between healthy and osteoporotic subjects.     

Proton density fat fraction (PDFF) MRI for differentiation of benign and malignant vertebral lesions

Objectives

To investigate whether proton density fat fraction (PDFF) measurements using a six-echo modified Dixon sequence can help to differentiate between benign and malignant vertebral bone marrow lesions.

Methods

Sixty-six patients were prospectively enrolled in our study. In addition to conventional MRI at 3.0-Tesla including at least sagittal T2-weighted/spectral attenuated inversion recovery and T1-weighted sequences, all patients underwent a sagittal six-echo modified Dixon sequence of the spine. The mean PDFF was calculated using regions of interest and compared between vertebral lesions. A cut-off value of 6.40% in PDFF was determined by receiver operating characteristic curves and used to differentiate between malignant (< 6.40%) and benign (≥ 6.40%) vertebral lesions.

Results

There were 77 benign and 44 malignant lesions. The PDFF of malignant lesions was statistically significant lower in comparison with benign lesions (p < 0.001) and normal vertebral bone marrow (p < 0.001). The areas under the curves (AUC) were 0.97 for differentiating benign from malignant lesions (p < 0.001) and 0.95 for differentiating acute vertebral fractures from malignant lesions (p < 0.001). This yielded a diagnostic accuracy of 96% in the differentiation of both benign lesions and acute vertebral fractures from malignancy.

Conclusion

PDFF derived from six-echo modified Dixon allows for differentiation between benign and malignant vertebral lesions with a high diagnostic accuracy.

Key Points

? Establishing a diagnosis of indeterminate vertebral lesions is a common clinical problem? Benign bone marrow processes may mimic the signal alterations observed in malignancy? PDFF differentiates between benign and malignant lesions with a high diagnostic accuracy? PDFF of non-neoplastic vertebral lesions is significantly higher than that of malignancy? PDFF from six-echo modified Dixon may help avoid potentially harmful bone biopsy

     

肝脏局灶病变血供对表观扩散系数的影响

目的　研究肝脏局灶病变的血供对病灶表观扩散系数 (apparentdiffusioncoefficient,ADC)的影响。方法　研究对象包括 87例病人 ,共 1 59个肝脏局灶病变 ,采用不同的b值和b值差的扩散加权成像 (diffusion weightedimaging,DWI)技术对各病灶及肝脏、脾脏及胆囊进行ADC值的测量。结果小b值和b值差所检测到的ADC值受组织或病变内血流灌注的影响 ,海绵状血管瘤的平均ADC值最高 (7 64× 1 0 - 3mm2 /s) ,富血供恶性肿瘤的平均ADC值明显高于乏血供恶性肿瘤 (分别为 3 47×1 0 - 3mm2 /s和 2 39× 1 0 - 3mm2 /s,t=2 39,P <0 0 1 ) ,肝囊肿的ADC值几乎不受b值和b值差的影响。结论　当利用小b值和小b值差进行DWI时 ,组织或病变的ADC值受血流灌注的影响较大。DWI及ADC值测量可在一定程度上反映肝脏局灶病变的血供     

Diagnostic interplay of proton magnetic resonance spectroscopy and diffusion weighted images with apparent diffusion coefficient values in suspicious breast lesions

Aim of the work

To study the diagnostic performance of combined single voxel 1H-MRS and DW-MRI with ADC values as a non-contrast diagnostic tool, compared to the DCE-MRI, in suspicious breast lesions.

Comparison between two-point and four-point methods for quantification of apparent diffusion coefficient of normal liver parenchyma and focal lesions. Value of normalization with spleen

Purpose

To compare two quantification techniques of apparent diffusion coefficient (ADC), both in normal liver parenchyma and focal lesions, and to investigate any potential value of normalization.

Materials and methods

Fifty-six consecutive patients underwent MRI examination of the liver, including a single shot spin-echo echo planar imaging diffusion sequence with four b-values (0, 50, 500 and 1000 s/mm²). ADC maps were reconstructed based on a two-point method (b-values: 500 and 1000 s/mm²) and a four-point method (b-values: 0, 50, 500 and 1000 s/mm²). Comparison of absolute ADC measurements of the liver, benign and malignant focal lesions was performed between the two- and four-point techniques. The same analysis was done on normalized ADC values (absolute ADC values divided by spleen ADC values).

Results

The difference between mean two-point and four-point ADC values of normal liver (absolute: 1.237 × 10⁻³, 1.615 × 10⁻³ mm²/s, normalized: 1.40, 1.52, respectively) was statistically significant (p < 0.0001 and p = 0.0061). Significantly higher absolute ADC values of benign and malignant lesions were recorded with the four-point method (2.860 × 10⁻³ and 1.307 × 10⁻³ mm²/s) over the two-point method (2.243 × 10⁻³, and 1.011 × 10⁻³ mm²/s) (p < 0.0001 in both) while the same differences in normalized values were proven statistically non-significant for benign lesions (p = 0.788) and statistically significant for malignant lesions (p = 0.015). Both differences in absolute and normalized ADC values of benign versus malignant lesions based on two- and four-point methods were found to be significant (p < 0.0001).

Conclusion

ADC quantification of the liver may be performed with a two-point method (b-values of 500 and 1000 s/mm²), while normalization of ADC measurements with the spleen is not further improving lesion characterization.     

Diffusion-weighted magnetic resonance imaging for assessment of lung lesions: repeatability of the apparent diffusion coefficient measurement

Purpose

To establish repeatability of apparent diffusion coefficients (ADCs) acquired from free-breathing diffusion-weighted magnetic resonance imaging (DW-MRI) in malignant lung lesions and investigate effects of lesion size, location and respiratory motion.

Methods

Thirty-six malignant lung lesions (eight patients) were examined twice (1- to 5-h interval) using T1-weighted, T2-weighted and axial single-shot echo-planar DW-MRI (b?=?100, 500, 800 s/mm²) during free-breathing. Regions of interest around target lesions on computed b?=?800 s/mm² images by two independent observers yielded ADC values from maps (pixel-by-pixel fitting using all b values and a mono-exponential decay model). Intra- and inter-observer repeatability was assessed per lesion, per patient and by lesion size (> or <2 cm) or location.

Results

ADCs were similar between observers (mean ± SD, 1.15?±?0.28?×?10^-3 mm²/s, observer 1; 1.15?±?0.29?×?10^-3 mm²/s, observer 2). Intra-observer coefficients of variation of the mean [median] ADC per lesion and per patient were 11 % [11.4 %], 5.7 % [5.7 %] for observer 1 and 9.2 % [9.5 %], 3.9 % [4.7 %] for observer 2 respectively; inter-observer values were 8.9 % [9.3 %] (per lesion) and 3.0 % [3.7 %] (per patient). Inter-observer coefficient of variation (CoV) was greater for lesions <2 cm (n?=?20) compared with >2 cm (n?=?16) (10.8 % vs 6.5 % ADC_mean, 11.3 % vs 6.7 % ADC_median) and for mid (n?=?14) vs apical (n?=?9) or lower zone (n?=?13) lesions (13.9 %, 2.7 %, 3.8 % respectively ADC_mean; 14.2 %, 2.8 %, 4.7 % respectively ADC_median).

Conclusion

Free-breathing DW-MRI of whole lung achieves good intra- and inter-observer repeatability of ADC measurements in malignant lung tumours.

Key Points

? Diffusion-weighted MRI of the lung can be satisfactorily acquired during free-breathing ? DW-MRI demonstrates high contrast between primary and metastatic lesions and normal lung ? Apparent diffusion coefficient (ADC) measurements in lung tumours are repeatable and reliable ? ADC offers potential in assessing response in lung metastases in clinical trials     

Comparison of apparent diffusion coefficient in spondylarthritis axial active inflammatory lesions and type 1 modic changes

Objective

The goal of this study was to evaluate whether the values of ADC in spondylarthritis axial active inflammatory lesions are different from ADC values in type 1 Modic changes.

Subjects and methods

95 patients with recent lumbar pain, including 46 patients with diagnosed or suspected spondylarthritis and 49 patients with purely degenerative history, underwent spine MRI. T1w, STIR, and diffusion-weighted images (DWI) were obtained. Two musculoskeletal radiologists interpreted the images. Axial active inflammatory lesions from the SpA group and type 1 Modic changes from the degenerative group were identified on T1w and STIR sequences. ADC values from these lesions and from healthy subchondral bone were compared.

Results

All axial active inflammatory lesions (n = 27) and type 1 Modic changes (n = 22) identified in T1w and STIR images were visible on DWI. ADC values were significantly higher (p < 0.05) for axial active inflammatory lesions (median = 0.788 × 10⁻³ mm²/s, IQR 25–75 [0.7 × 10⁻³ mm²/s; 0.9 × 10⁻³ mm²/s]) than for type 1 Modic changes (median = 0.585 × 10⁻³ mm²/s, IQR 25–75 [0.55 × 10⁻³ mm²/s; 0.60 × 10⁻³ mm²/s]) and normal subchondral bone (median = 0.443 × 10⁻³ mm²/s, IQR 25–75 [0.40 × 10⁻³ mm²/s; 0.50 × 10⁻³ mm²/s]). Intra-class correlation coefficients for intra- and inter-reader ADC values comparison were excellent (0.89 and 0.98 respectively).

Conclusion

DWI is a sensitive and fast sequence that offer the possibility of quantifying diffusion coefficients of the lesions, which could help to discriminate between spondylarthritis axial active inflammatory and type 1 Modic changes.     

MR脂肪定量技术在腰椎椎体骨髓脂肪含量评估中的研究进展

骨髓是人体内重要的造血和免疫器官,其内脂肪含量的变化对于疾病的精准诊断和疾病严重程度的分级至关重要。由于MRI对软组织和脂肪组织等具有较好的分辨力,因而对骨髓脂肪含量的定量评估起着不可替代的作用。就扩散加权成像、磁共振波谱成像、化学位移成像以及水脂分离技术等MR脂肪定量技术在腰椎椎体骨髓脂肪含量定量评估方面的应用及研究进展予以综述。     

Apparent diffusion coefficient of the vertebral bone marrow in children with Gaucher's disease type I and III

Purpose

To assess apparent diffusion coefficient (ADC) as a quantitative parameter for detection of vertebral bone marrow infiltration in children with Gaucher’s disease type I and III.

Material and methods

Prospective study was conducted on 20 infants and children (14 M, 6 F; aged 31–61 months; mean age 46 months) with Gaucher’s disease type I (n?=?13) and III (n?=?7), and 20 age and sex matched controls. They underwent routine and diffusion-weighted MR imaging of the lumbar spine using echo planar imaging with b value of 0, 500 and 1000 sec/mm2. The ADC value of the lumbar vertebral bone marrow was compared in different phenotypes and genotypes; and correlated with bone marrow burden score (BMB), chitotriosidase level, hemoglobin and platelet count.

Results

The mean ADC value of marrow infiltration in patients with Gaucher’s disease (0.39?±?0.06?×?10^?3 mm²/s) was significantly lower (P?=?0.001) than that of vertebral bone marrow in controls (0.54?±?0.05?×?10^?3 mm²/s). The cut-off ADC value used to differentiate patients with Gaucher’s disease from controls was (0.47?×?10^?3 mm²/s); with sensitivity of 95 %; specificity of 95 % and area under the curve of 0.986. The L444P/L444P mutation had significantly lower ADC value compared to other mutations (P?=?0.001). The mean ADC value of the bone marrow negatively correlated with BMB (r?=??0.831; P?=?0.001), and biomarkers of disease activity including chitotriosidase (r?=??0.542; P?=?0.014), hemoglobin (r?=??0.727; P?=?0.001) and platelets (r?=??0.698; P?=?0.001).

Conclusion

We concluded that there is significant difference in the ADC value of vertebral bone marrow between children with Gaucher’s disease and controls, and the ADC value correlated well with genotyping and some biomarkers of disease activity.     

肝脏局灶性病变的定量评价特征:表观扩散系数值和T2值的比较

目的比较表观扩散系数(ADC)值和T2值两种定量方法区分肝脏良恶性的局灶性病变的效能。材料与方法 73例病人共215个已确诊的肝脏局灶性病变(115个良性,100个恶性)进行1.5TMRI,包括呼吸触发的单次激发自旋回波扩散加权(b=50,400,800)和双回波T2加权快速自旋回波(TR=3000ms;TE1=84ms;TE2=228ms)成像。计算肝脏局灶性病变的扩散加权系数值和T2值,评估它们诊断恶性病变的敏感性、特异性和准确性。结果恶性肿瘤的平均ADC值(1.07×10-3mm2/s)明显低于良性病变的(1.86×10-3mm2/s)(P<0.05);但当采用最佳临界值1.25×10-3mm2/s诊断恶性肿瘤时,存在20例假阳性和20例假阴性,敏感度79%,特异度82.6%,诊断准确度为80.9%。恶性肿瘤的平均T2值(64.4ms)明显低于良性病变的(476.1ms)(P<0.05)。当采用107ms的临界值进行诊断时,出现22例假阳性和1例假阴性,敏感度99%,特异度80.9%,诊断准确度为89.3%。结论在诊断肝脏恶性肿瘤中,T2值的定量评价比ADC值有着更高的灵敏度和准确度。     

Methods and applications of diffusion imaging of vertebral bone marrow

Diffusion-weighted imaging (DWI) is an MRI technique that is sensitive to random water movements at spatial scales far below typical MRI voxel dimensions. DWI is a valuable tool for the diagnoses of diseases that involve alterations in water mobility. In the spine, DWI has proven to be a highly useful method for the differential diagnosis of benign and malignant compression fractures. In these pathologies, the microscopic structure of bone marrow is altered in a very different ways, leading to different water mobility, which can be depicted by DWI. Most of the pulse sequences developed for MRI can be adapted for DWI. However, these DWI-adapted sequences are frequently affected by artifacts, mostly caused by physiological motion. Therefore, the introduction of additional correction techniques, or even the development of new sequences is necessary. The first part of this article describes the principles of DWI and the sequences used for DWI of the spine: spin echo (SE), turbo spin echo (TSE), single-shot echo planar imaging (EPI), and steady-state free precession (SSFP) sequences. In the second part, clinical applications of DWI of the spinal bone marrow are extensively discussed.