Sagittal Diffusion-weighted Imaging Research Articles

Diagnostic Accuracy of Quantitative Imaging Biomarkers in the Differentiation of Benign and Malignant Vertebral Lesions

PurposeTo compare and combine the diagnostic performance of the apparent diffusion coefficient (ADC) derived from diffusion-weighted imaging (DWI) and proton density fat fraction (PDFF) derived from chemical-shift encoding (CSE)-based water-fat magnetic resonance imaging (MRI) for distinguishing benign and malignant vertebral bone marrow lesions (VBML).MethodsA total of 55 consecutive patients with 53 benign (traumatic, inflammatory and primary) and 36 malignant (metastatic and hematologic) previously untreated VBMLs were prospectively enrolled in this IRB-approved study and underwent sagittal DWI (single-shot spin-echo echo-planar with multi-slice short TI inversion recovery fat suppression) and CSE-based MRI (gradient-echo 6‑point modified Dixon) in addition to routine clinical spine MRI at 1.5 T or 3.0 T. Diagnostic reference standard was established according to histopathology or imaging follow-up. The ADC = ADC (0, 800) and PDFF = fat / (water + fat) were calculated voxel-wise and examined for differences between benign and malignant lesions.ResultsThe ADC and PDFF values of malignant lesions were significantly lower compared to benign lesions (mean ADC 861 × 10−6 mm2/s vs. 1323 × 10−6 mm2/s, p < 0.001; mean PDFF 3.1% vs. 28.2%, p < 0.001). The areas under the curve (AUC) and diagnostic accuracies were 0.847 (p < 0.001) and 85.4% (cut-off at 1084.4 × 10−6 mm2/s) for ADC and 0.940 (p < 0.001) and 89.9% for PDFF (cut-off at 7.8%), respectively. The combined use of ADC and PDFF improved the diagnostic accuracy to 96.6% (malignancy if ADC ≤ 1118.2 × 10−6 mm2/s and PDFF ≤ 20.0%, otherwise benign).ConclusionQuantitative evaluation of both ADC and PDFF was useful in differentiating benign VBMLs from malignancy. The combination of ADC and PDFF improved the diagnostic performance and yielded high diagnostic accuracy for the differentiation of benign and malignant VBMLs.

Application of bi-planar reduced field-of-view DWI (rFOV DWI) in the assessment of muscle-invasiveness of bladder cancer

ObjectivesTo compare the image quality of the reduced field-of-view (rFOV) diffusion-weighted imaging (DWI) with the full field-of-view (fFOV) DWI in the assessment of bladder cancer (BC); and to explore the possible superiority of bi-planar (axial and sagittal) rFOV DWI over single planar fFOV DWI in predicting muscle-invasiveness of BC. Materials and methodsThis retrospective study analyzed 61 patients with BC who underwent DWI sequences including axial fFOV DWI, axial rFOV DWI, and sagittal rFOV DWI. Qualitative and quantitative image quality assessment were compared between axial fFOV DWI and rFOV DWI sequences. The tumor with its base could be clearly displayed on DWI was defined as the evaluable lesion, and the number of evaluable lesions detected from single axial fFOV DWI, axial rFOV DWI, sagittal rFOV DWI, and bi-planar rFOV DWI sequences was recorded and compared. The apparent diffusion coefficient (ADC) was compared between non-muscular-invasive bladder cancer (NMIBC) and muscular-invasive bladder cancer (MIBC) based on the sequences of axial fFOV DWI and rFOV DWI, respectively. Vesical Imaging-Reporting and Data System (VI-RADS) was introduced to evaluate the overall risk of muscle-invasiveness of BC and receiver operating characteristic (ROC) curve analysis was applied to assess the diagnostic performance. ResultsThe contrast-to-noise ratio (CNR) of the rFOV DWI was significantly higher than that of fFOV DWI (p < 0.01), while the signal-to-noise ratio (SNR) was significantly lower than that of fFOV DWI (p < 0.01). The subjective score of rFOV DWI was significantly higher than that of fFOV DWI (p < 0.01). The ADC value of the MIBC group was significantly lower than that of the NMIBC in both rFOV DWI and fFOV DWI (all p < 0.01). The number of evaluable lesions detected from the bi-planar rFOV DWI was significantly higher than that detected from the single axial fFOV DWI, axial rFOV DWI, and sagittal rFOV DWI (all p < 0.01). VI-RADS based on the bi-planar rFOV DWI offered high predictive power (the area under the ROC curve, 0.946) for predicting the presence of muscle-invasiveness of BC. ConclusionBi-planar rFOV DWI may provide more diagnostic confidence than the single planar DWI for predicting the presence of muscle-invasiveness in BC, with improved image quality over the fFOV DWI.

Clinical suspicion of spondylodiscitis with equivocal MRI findings: does diffusion-weighted imaging prove helpful here?

Despite the high sensitivity of magnetic resonance imaging (MRI), early detection of spondylodiscitis (SpD) remains challenging due to its low specificity. To assess the diagnostic value of diffusion-weighted imaging (DWI) in suspected cases of SpD with ambiguous early MRI findings in the differentiation of degenerative disorders (DD). In this prospective study, 52 patients suspected of having SpD underwent a whole-spine 3-T MRI scan comprising sagittal DWI. Of 58 conspicuous, T2-weighted, signal increased discs, 39 were successfully evaluated using DWI. Apparent diffusion coefficient (ADC) values and ADC maps were blindly analyzed using the region of interest of the conspicuous disc and a normal adjacent reference disc. Intraindividual ratios (conspicuous disc: reference disc) were calculated. All conspicuous discs showed increased absolute ADC values, which did not differ significantly between SpD (n = 22) and DD (n = 17). However, ADC ratio was significantly higher in SpD vs. DD (P < 0.05). In receiver operating characteristic curve analysis, an ADC ratio threshold of 1.6 resulted in 45% sensitivity and 88% specificity (area under the curve = 0.69) for SpD diagnosis. The absolute ADC value does not provide a reliable diagnosis of SpD. Increased diffusivity can be an indication of infection but should always be discussed in the context of existing disc degeneration.

Sagittal diffusion-weighted imaging in preventing the false-negative diagnosis of acute brainstem infarction: Confirmation of the benefit by anatomical characterization of false-negative lesions.

Background:In some cases of acute brainstem infarction (BI), standard axial diffusion-weighted imaging (DWI) does not show a lesion, leading to false-negative (FN) diagnoses. It is important to recognize acute BI accurately and promptly to initiate therapy as soon as possible.Methods:Of the 171 patients with acute cerebral infarctions in our institution who were examined, 16 were diagnosed with true-positive BI (TP-BI) and six with FN-BI. We evaluated the effectiveness of sagittal DWI in accurately diagnosing acute BI and sought to find the cause of its effectiveness by the anatomical characterization of FN-BIs.Results:Considering the direction of the brainstem perforating arteries, we supposed that sagittal DWI might more effectively detect BIs than axial DWI. We found that sagittal DWI detected all FN-BIs more clearly than axial DWI. The mean time between the onset of symptoms and initial DWI was significantly longer in the TP group (17.6 ± 5.5 h) than in the FN group (5.0 ± 1.2 h; P < 0.0001). The lesion volumes were much smaller in FN-BIs (259 ± 82 mm3) than in TP-BIs (2779 ± 767 mm3; P = 0.0007). FN-BIs had a significant inverse correlation with the ventrodorsal length of infarcts (FN 3.5 ± 1.1 mm, TP 11.4 ± 3.6 mm; P < 0.0004) and no correlation with other size parameters such as rostrocaudal thickness and lateral width.Conclusion:Anatomical characterization clearly confirmed that the addition of sagittal DWI to the initial axial DWI in suspected cases of BI ensures its accurate diagnosis and improves the patient’s prognosis.

Additional diagnostic value of Diffusion-Weighted Magnetic Resonance Imaging to conventional Magnetic Resonance Imaging in local staging of primary uterine cervical cancer

Objective: Magnetic resonance (MR) imaging is a helpful modality for detecting and staging gynecological cancers. Diffusion-weighted imaging (DWI) could improve the accuracy rates of MR imaging. The aim of this study was to assess the additional diagnostic value of DWI over conventional MR imaging in assessing the local extent of primary cervical cancer. Method: Forty patients with primary uterine cervical cancer were enrolled in the study, prospectively. All MR examinations were performed using a 1.5 Tesla Unit MR with a body coil. Sagittal and axial T2-weighted MR images, sagittal and axial DWI (at b values of 0, 500,1000 s/mm 2 ) with ADC maps were obtained. The images were evaluated by two different readers independently. The degree of the interobserver agreement between the radiologists was assessed with kappa statistics. Results: Mean age of the study population was 50.7±11.1 years. Kappa values ranged from 0.76 to 1 for both readers indicating excellent agreement. Accuracy rates were as follows for reader 1 respectively with conventional and conventional plus DWI; stromal invasion 0.92/0.95; parametrial invasion 0.87/0.92; vaginal invasion 0.87/0.92; pelvic sidewall invasion 0.90/0.97. Accuracy rates were as follows for reader 2 respectively with conventional and conventional plus DWI images; stromal invasion 0.90/0.95; parametrial invasion 0.87/0.92; vaginal invasion 0.87/0.97; pelvic sidewall invasion 0.90/0.95. Conclusions: MR provides satisfactory accuracy rates in the evaluation of the local extent of uterine cervical carcinoma, and adding DWI improves the diagnostic performance of conventional MR.

Twenty-Five Diagnoses on Midline Images of the Brain: From Fetus to Child to Adult.

Midsagittal images of the brain provide a wealth of anatomic information and may show abnormalities that are pathognomonic for particular diagnoses. Using an anatomy-based approach, the authors identify pertinent anatomic structures to serve as a checklist when evaluating these structures. Subregions evaluated include the corpus callosum, pituitary gland and sellar region, pineal gland and pineal region, brainstem, and cerebellum. The authors present 25 conditions with characteristic identifiable abnormalities at midsagittal imaging. Midsagittal views from multiple imaging modalities are shown, including computed tomography, ultrasonography, and magnetic resonance (MR) imaging. Standard MR imaging sequences are shown, as well as fetal MR and sagittal diffusion-weighted images. To demonstrate these conditions, fetal, neonatal, childhood, adolescent, and young adulthood images are reviewed. The differentiation of normal variants is guided by the understanding of anatomy and pathology. When a specific diagnosis is not possible, the authors present information to evaluate differential considerations and discuss when follow-up imaging may be indicated. The authors hope each case will clarify a pertinent differential diagnosis, appropriately guide patient management, and improve understanding of normal anatomy and identification of pathologic entities. It is in these hopes that the authors have presented a checklist of pertinent anatomy and pathologic entities that can build on existing search patterns. Improved confidence and accuracy in the evaluation of midsagittal images will benefit physicians and patients. ©RSNA, 2018.

Tumor radiomic heterogeneity: Multiparametric functional imaging to characterize variability and predict response following cervical cancer radiation therapy.

Robust approaches to quantify tumor heterogeneity are needed to provide early decision support for precise individualized therapy. To conduct a technical exploration of longitudinal changes in tumor heterogeneity patterns on dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI) and FDG positron emission tomography / computed tomography (PET/CT), and their association to radiation therapy (RT) response in cervical cancer. Prospective observational study with longitudinal MRI and PET/CT pre-RT, early-RT (2 weeks), and mid-RT (5 weeks). Twenty-one FIGO IB2 -IVA cervical cancer patients receiving definitive external beam RT and brachytherapy. 1.5T, precontrast axial T1 -weighted, axial and sagittal T2 -weighted, sagittal DWI (multi-b values), sagittal DCE MRI (<10 sec temporal resolution), postcontrast axial T1 -weighted. Response assessment 1 month after completion of treatment by a board-certified radiation oncologist from manually delineated tumor volume changes. Intensity histogram (IH) quantiles (DCE SI10% and DWI ADC10% , FDG-PET SUVmax ) and distribution moments (mean, variance, skewness, kurtosis) were extracted. Differences in IH features between timepoints and modalities were evaluated by Skillings-Mack tests with Holm's correction. Area under receiver-operating characteristic curve (AUC) and Mann-Whitney testing was performed to discriminate treatment response using IH features. Tumor IH means and quantiles varied significantly during RT (SUVmean : ↓28-47%, SUVmax : ↓30-59%, SImean : ↑8-30%, SI10% : ↑8-19%, ADCmean : ↑16%, P < 0.02 for each). Among IH heterogeneity features, FDG-PET SUVCoV (↓16-30%, P = 0.011) and DW-MRI ADCskewness decreased (P = 0.001). FDG-PET SUVCoV was higher than DCE-MRI SICoV and DW-MRI ADCCoV at baseline (P < 0.001) and 2 weeks (P = 0.010). FDG-PET SUVkurtosis was lower than DCE-MRI SIkurtosis and DW-MRI ADCkurtosis at baseline (P = 0.001). Some IH features appeared to associate with favorable tumor response, including large early RT changes in DW-MRI ADCskewness (AUC = 0.86). Preliminary findings show tumor heterogeneity was variable between patients, modalities, and timepoints. Radiomic assessment of changing tumor heterogeneity has the potential to personalize treatment and power outcome prediction. 2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1388-1396.

Usefulness of the quantitative evaluation of diffusion-weighted mri in the diagnosis of anterior cruciate ligament tears.

To evaluate the usefulness of the diffusion-weighted imaging (DWI) in the diagnosis of anterior cruciate ligament (ACL) tear using the contrast-to-noise ratio (CNR) and apparent diffusion coefficient (ADC) values according to the different b values. Institutional review board approval was acquired. We evaluated 74 patients (M:F = 43:31, mean age of 44 years) who underwent 3.0 Tesla knee MR with DWI because of the possibility of ACL tear due to trauma. Region of interest measurements were performed. We (two radiologists) measured the signals of the DWI and derived ADC values on the oblique sagittal DWI with b values of 0, 600, and 1000. The diagnostic accuracies of the conventional MR image and each DWI with an ADC value with a different b value were evaluated. The CNR and ADC values were compared using the Mann-Whitney U-test. The diagnostic performances of the various imaging methods were evaluated using the sensitivity, specificity, and accuracy for differentiating between normal and ACL injury as determined by the use of conventional MRI with additional DWIs with McNemar test. The arthroscopic or clinical findings were used as the reference standard. The mean CNRs of ligament tears with b values of 600 and 1000 were significantly higher than those of normal ligament (22 versus 7 and 9 versus 4, P value < 0.05). The sensitivities and the accuracies of the DWI were significantly lower than the conventional MRIs (P value < 0.001). The CNRs of the torn ACL with each b value (600 and 1000) were significantly higher those of than normal ligament, although the ADC values of the torn ligament were not different from normal ligament. Addition of the DWI to the conventional MRI did not improve diagnostic performance. J. Magn. Reson. Imaging 2016;44:1116-1122.

Are Second Trimester Apparent Diffusion Coefficient Values of the Short Uterine Cervix Associated with Impending Preterm Delivery?

Purpose To prospectively determine whether the apparent diffusion coefficient (ADC) of the cervix is associated with preterm delivery in asymptomatic patients with a sonographic cervical length of 15 mm or less and positive fetal fibronectin test results between 23 and 28 weeks of gestation. Materials and Methods The institutional review board approved this prospective hypotheses-generating study. A total of 30 pregnant women (mean gestational age, 26 weeks) with a sonographic short cervix (≤15 mm) underwent pelvic 1.5-T magnetic resonance (MR) imaging. Oblique sagittal diffusion-weighted images were obtained with b values of 0, 400, and 800 sec/mm(2). ADC values at MR imaging of the subglandular and stromal cervix and the difference between both were correlated to the interval to delivery. Receiver operating characteristic curve analysis was performed to obtain sensitivity and specificity of ADC values in association with delivery within 7 days. Results Eight (27%) of 30 patients delivered within 6 or 7 days after MR imaging (impending delivery group), and 22 (73%) of 30 patients delivered between 18 and 89 days after imaging (mean, 55 days) (late delivery group). Mean subglandular ADC and mean ADC difference were higher (P < .001) in patients with impending delivery than in those with late delivery ([2406.3 ± 166.0] × 10(-6) mm(2)/sec vs [1708.9 ± 108.1] × 10(-6) mm(2)/sec and [657.3 ± 129.9] × 10(-6) mm(2)/sec vs [69.2 ± 70.2] × 10(-6) mm(2)/sec, respectively). Subglandular ADC inversely correlated with the interval between MR imaging and delivery (r = -0.75). Receiver operating characteristic curve analysis of subglandular ADC revealed 100% sensitivity (95% confidence interval: 63.1, 100) and 100% specificity (95% confidence interval: 84.6, 100) in association with impending delivery with a 1921 × 10(-6) mm(2)/sec threshold. Stromal ADC and sonographic cervical length showed no difference between groups (P = .072 and P = .511, respectively). Conclusion Cervical subglandular ADC at MR imaging is associated with impending preterm birth in patients with a short sonographic cervix. (©) RSNA, 2016.

Correction of Gradient Nonlinearity Bias in Quantitative Diffusion Parameters of Renal Tissue with Intra Voxel Incoherent Motion.

Spatially nonuniform diffusion weighting bias as a result of gradient nonlinearity (GNL) causes substantial errors in apparent diffusion coefficient (ADC) maps for anatomical regions imaged distant from the magnet isocenter. Our previously described approach effectively removed spatial ADC bias from 3 orthogonal diffusion-weighted imaging (DWI) measurements for monoexponential media of arbitrary anisotropy. This work evaluates correction feasibility and performance for quantitative diffusion parameters of the 2-component intravoxel incoherent motion (IVIM) model for well-perfused and nearly isotropic renal tissue. Sagittal kidney DWI scans of a volunteer were performed on a clinical 3T magnetic resonance imaging scanner near isocenter and offset superiorly. Spatially nonuniform diffusion weighting caused by GNL resulted both in shifting and broadening of perfusion-suppressed ADC histograms for off-center DWI relative to unbiased measurements close to the isocenter. Direction-average diffusion weighting bias correctors were computed based on the known gradient design provided by the vendor. The computed bias maps were empirically confirmed by coronal DWI measurements for an isotropic gel-flood phantom. Both phantom and renal tissue ADC bias for off-center measurements was effectively removed by applying precomputed 3D correction maps. Comparable ADC accuracy was achieved for corrections of both b maps and DWI intensities in the presence of IVIM perfusion. No significant bias impact was observed for the IVIM perfusion fraction.

Rostrocaudal Thickness on Sagittal Diffusion-weighted Imaging as a Predictor of Motor Deficits in an Acute Isolated Pontine Infarction

The relationship between infarct dimensions and neurologic severity in patients with acute pontine infarctions remains unclear. This study aimed to clarify the morphometric predictive value of magnetic resonance imaging for motor deficits in pontine infarction. Nineteen patients with an acute pontine infarction (12 males and 7 females, 70.6 ± 13.5 years [mean age ± SD]) had ventrodorsal length and rostrocaudal thickness and width retrospectively measured as parameters of infarct size on axial and sagittal diffusion-weighted imaging (DWI). Each patient's functional score (FS) based on Brunnstrom scale (upper limb, hand, and lower limb) was assessed. The functional score of bulbar symptoms was coded as follows: 2, none; 1, dysarthria or dysphasia; and 0, both. The mean FS was compared with each infarct size parameter and the patients' clinical features. Rostrocaudal thickness on sagittal DWI was the parameter most closely correlated with FS (Spearman rank correlation coefficient (rs) = -.474, P = .040). However, there is apparently no association between FS and infarct size with correction for age. FS was most severe in patients with an atherothrombotic infarction; it was mildest in patients with a lacunar infarction (value of K [Kruskal-Wallis] = 9.0, P = .015). The branch orifices of the pontine paramedian arteries could be narrowed by atheromatous plaques within the basilar artery. These atheromatous lesions involving multiple branching paramedian arteries probably cause rostrocaudally thick infarctions. A pontine infarction extending rostrocaudally along the corticospinal tract may cause severe motor impairments.

The Value of Diffusion-Weighted Magnetic Resonance Imaging in Assessing the Response of Locally Advanced Cervical Cancer to Neoadjuvant Chemotherapy

The objective of this study was to investigate whether magnetic resonance diffusion-weighted imaging (DWI) of locally advanced cervical cancer (LACC) both in the sagittal and axial planes could be used to assess the response of LACC to neoadjuvant chemotherapy (NACT). Thirty women with LACC received conventional magnetic resonance imaging and DWI at 3 different times (before NACT, 2 weeks after the first NACT, and 2 weeks after the second NACT). Treatment response was determined according to the change in tumor size 2 weeks after the second NACT, and they were classified as the effective group and the ineffective group. The apparent diffusion coefficients (ADCs) were compared between 2 imaging planes, and dynamic changes in ADCs were observed in different chemotherapy-sensitive groups and imaging planes. One-way analysis of variance was calculated between those ADC parameters and tumor response. The effective chemotherapy rate was 76.67%. Apparent diffusion coefficient values of the axial plane at 3 different times were 0.88 (SD, 0.08) × 10⁻³ mm²/s, 0.96 (SD, 0.10) × 10⁻³ mm²/s, and 1.19 (SD, 0.11) × 10⁻³ mm²/s, respectively. Meanwhile, ADC values of the sagittal planes were 0.89 (SD, 0.09) × 10⁻³ mm²/s, 0.97 (SD, 0.12) × 10⁻³ mm²/s, and 1.19 (SD, 0.12) × 10⁻³ mm²/s at 3 different stages. There were no statistical differences between the ADC values of the 2 planes at 3 different times (P = 0.927, P = 0.863, P = 0.946). Apparent diffusion coefficients 2 weeks after the first NACT were significantly increased compared with those before chemotherapy both in the axial and sagittal planes (P = 0.003, P = 0.012). In the ineffective group, ADCs 2 weeks after the first NACT were not statistically higher than those before chemotherapy (axial planes, P = 0.694; sagittal planes, P = 0.900). After 2 weeks of the first NACT, ADCs in both planes were obviously increased in the effective group than those in the ineffective group (P = 0.043, P = 0.022). The axial and sagittal DWI may detect the changes in LACC after therapy. Apparent diffusion coefficient values measured both in the 2 planes may be used to evaluate the response of LACC to NACT.

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

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. 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. 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. 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.

Exploration for the optimal b value in diffusion-weighted MRI scanning for the differentiation between benign and malignant vertebral fractures

目的 探讨应用扩散加权成像(DWI)鉴别良、恶性椎体骨折时的最佳扩散敏感系数值(b值).方法22例椎体压缩性骨折病人分为良性组(10例,因骨质疏松或外伤引起)和恶性组(12例,转移瘤引起),行前瞻性矢状面MR扩散加权成像,用定性评分和定量计算信噪比(SNR)的方法来比较不同b值DWI的质量.二组患者病变椎体的表观扩散系数(ADC)值也做了对比.结果选用的b值越小,DWI的图像质量越清晰,定性评分值越高.在b值为0、100、200、300、400、500、600、700、800s/mm2时,图像SNR分别为22.7±3.4、24.6±3.6、22.2±3.2、19.2±2.6、10.3±2.1、8.8±2.7、6.8±2.7、5.8±1.7和5.8±2.1.各组间差异有非常显著性意义(F=150.13,P＜0.01).良、恶性椎体骨折ADC值的差异也有显著意义(P＜0.05).但在b值为0、100s/mm2的DWI中,4例良性椎体骨折误诊为恶性.结论当DWI应用于鉴别良、恶性椎体骨折时,最佳b值应为300s/mm2左右为宜.b值过大,使噪音本已较明显的DWI质量和SNR进一步降低,影响对病变的分析.b值过小,则降低DWI中水分子的扩散权重,易导致良性椎体骨折假阳性的发生。