Preliminary study of whole body MR diffusion weighted imaging in detecting pediatric primary and metastatic malignant tumor / 中华放射学杂志

ABSTRACT

Objective To assess the efficacy of whole body diffusion weighted imaging (WB-DWI) in detecting pediatric primary and metastatic malignant tumor. Methods WB-DWI was performed in 62 healthy pediatric volunteers and 40 pediatric patients with confirmed malignant tumors. The healthy volunteers were divided into three groups 0 to 12 months, more than 12 months to 5 years and more than 5 to 15 years. The characteristics of WB-DWI imaging were analyzed. McNemar test was used to compare the difference of detection on metastasis between WB-DWI and WB-DWI combined with MRI, CT. The mean apparent diffusion coefficient ( ADC ) values of primary tumors and metastases were measured by using paired t test and compared with those of corresponding body regions of control group. Results WB-DWI imaging shows that signal intensity of metaphysis gradually reduces with increasing age in the normal pediatric group. On WB-DWI primary malignant tumors showed 100％ (40/40) high signal intensity and metastases showed high signal intensity in 89.2％ (58/65) on WB-DWI, with a positive predictive value of 90. 6％ (58/64). The detecting rate for metastases increased to 95.4％ (62/65) when WB-DWI was combined with MRL/CT, with a positive predictive value of 95.4％ (62/65) there was no statistically significant difference ( x2 = 2. 25, P ＞ 0. 05 ). The ADC values of primary malignant tumor sites in head ( n = 5), liver(n=6), kidney(n=8), adrenal(n=ll) were (0.76 ±0. 19) ×10-3 , (0. 97 ±0.29) × 10-3,(0. 81 ±0. 12) × 10-3 and (0. 93 ±0. 28) × 10-3mm2/s and those of corresponding body regions of control group were (1.02 ±0. 11) × 10-3,(1.57 ±0.58) × 10-3, (1.19 ±0. 15) × 10-3 and (2.03 ±0.42) ×10-3mm2/s respectively, there were statistically significant difference( t values were 3.54,3. 84,7. 02 and 12. 57 ;P ＜ 0. 05 ). The A DC values of metastases sites in head ( n = 9 ), liver ( n = 13 ), kidney ( n = 17 ),bone(n =7) and lymph node(n =6) were (0. 88 ±0. 12) × 10-3, (0. 98 ±0. 10) × 10-3, (0. 89 ±0. 11 ) × 10-3, (0. 96 ±0. 15) × 10-3 and (0. 83 ±0. 14) × 10-3mm2/s, and those of corresponding body regions of control group were (1.01 ±0.09) × 10-3, (1.45 ±0.39) × 10-3, ( 1.31 ±0.27) × 10-3, ( 1.34 ±0. 20) × 10 -3 and ( 0. 99 ± 0. 08 ) × 10 -3 mm2/s, there were statistically significant difference ( t values 4. 09,45.50,6. 95,14. 00 and 9. 27 ;P ＜ 0. 05 ). Conclusions Increased signal intensity is more frequently observed in metaphysis of long bone in normal children on WB-DWI. With a high detection rate for primary and metastatic malignant tumors, WB-DWI combined with conventional CT; MRI can significantly improve their sensitivity.