| Objective: To study diffusion-weighted imaging (DWI) on patients with lumbar osteolytic metastases and evaluate the value of signal attenuation ratios (SARs) and apparent diffusion coefficients (ADCs) in diagnosis.Materials and Methods: 20 patients with lumbar osteolytic metastases (confirmed by clinic and pathology) and 10 controls were performed with sagittal SE TiWI, FSE T2WI, fat saturation FSE T2WI (FS-FSE T2WI) and single-shot spin-echo echoplanar DWI, respectively. The contrast noise ratios (CNRs) of the metastases on various series were compared. Meanwhile, on DWI with different b value, the SARs and ADCs of lumbar osteolytic metastases and normal vertebrae were analyzed. ADC maps were reconstructed in patients with lumbar osteolytic metastases.Results: (1) Gerneral MRI appearance: There were 23 lesions in 20 patients. The signal intensity of all lesions were showed hypointense on SE TiWI, hyperintense on FS-FSE T2WI and DWI, and mixed signal intensity (n=5), isointense (n=12) or slight hyperintense (n=6) onFSET2WI. (2) CNR: The CNRs of lumbar osteolytic metastases on FSE T2WI ( 5.6951 ±3.8203 ) were lower than those on SE TiWI ( 25.6232±11.7264 ) , FS-FSE T2WI ( 23.3708±7.4793 ) and DWl(b=600s/mm2) (24.6926±9.8715) (P<0.01) .The CNRs on SE TiWI, FS-FSE T2WI and DWI (b=600s/mm2) were similar (P>0.05). (3) SAR: On DWI, the SARs of lesions, normal vertebrae adjacent to lesions in patient group and normal vertebrae in control group were:b=165s/mm2-33.21±7.764%,20.41±5.254%,22.09±5.208%; b=360s/mm2 - 48.28±7.110%,27.18±5.038%,29.08±5.353%; b=600s/mm2 -59.64±7.371%, 33.82±5.747%, 34.02±4.498%. The SARs of lesions were evidently higher man normal vertebrae at the same imaging parameters (P<0.01). There was no difference between the SARs of the normal vertebrae adjacent to lesions and the controls (P>0.05). The differences of SARs of the same ROIs on DWI with differentb values were statistically significant (P<0.01): higher b values, higher SARs. (4) ADC: On DWI, the ADCs of lesions, normal vertebrae adjacent to lesions in patient group and normal vertebrae in control group were: b=165s/mm2 -2.487±0.696 × 10-3mm2/s, 1.359±0.41 × 10-3mm2/s, 1.509±0.406 × 10-3mm2/s; b=360s/mm2-1.867±0.364 X 10"3mm2/s, 0.883±0.193 X 10'3mm2/s, 0.96±0.21 X×10-3mm2/s; b=600s/mm2-1.538±0.301 × 10-3mm2/s, 0.676±0.156 × 10-3mm2/s, 0.698±0.115× 10-3mm2/s. The ADCs of lesions were evidently higher than that of normal vertebrae at the same imaging parameters (P<0.01). There was no difference in the ADCs between the normal vertebrae adjacent to lesions and the controls (P>0.05). The differences of ADCs of the same ROIs on DWI with different b values were statistically significant (P<0.01): higher b values, smaller ADCs. (5) Correlation between SAR and ADC: On DWI, there were positive correlations between the SARs and the ADCs of the same ROIs at the same parameters. The correlations were statistically significant (P<0.01). (6) ADC map: ADC maps could visually reflect the diffusion ability of various tissues. The metastases showed brighter signal than the normal vertebrae on the map.Conclusion: We could efficiently quantitive the diffusion characterization of the vertebrae on DWI.The lumbar osteolytic metastases and normal vertebrae could be accurately distinguished by comparing the SARs and ADCs.Postgraduate DapengHao (Radiology)Directed by Prof. Aide XuMD Wenjian Xu... |
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