Effects of Broad SPAIR Pulse, Continuous Fat Suppression Mode, Flow Compensation on Image Quality and Apparent Diffusion Coeffcient Reproducibility in iShim Diffusion-Weighted Imaging of the Abdomen at 3.0 T
He Sui1, Mengchao Zhang1, Hong Zeng1, and Lin Liu1

1Jilin University SINO-JAPAN Hospital, Changchun, China, People's Republic of

Synopsis

To detect the effects of Broad SPAIR Pulse, Continuous Fat Suppression Mode, Flow Compensation on Image Quality and Apparent Diffusion Coefficient Reproducibility in iShim Diffusion-Weighted Imaging of the Abdomen at 3.0 T

The continuous fat suppression technique and Broad SPAIR Pulse can increase the fat saturation efficiency and decrease the ghost artifacts, when combined with flow compensation technique, the image qualit y can be further improved without affect ADC values.

High quality of the iShim Diffusion-Weighted Imaging can give a great help of detection of disease.

Purpose:To study if the increased bandwidth and sharper spectral profile (Broad) SPAIR Pulse, dynamic field correction with multiple concatenations (PACE) with continuous fat suppression, flow compensation technique can increase the fat saturation efficiency, decrease the ghost artifacts and have an effect on the apparent diffusion coefficient (ADC) reproducibility. Materials and Methods:This prospective study was approved by the appropriate ethics committee and written informed consent was obtained from all healthy volunteers. Between August 2015 and October 2015, 30 healthy volunteers (18men, 12 women; mean age, 21 years) underwent diffusion-weighted imaging with iShim sequence settings A (diffusion scheme: monopolar,SAPIR bandwidth:default), B (diffusion scheme: Monopolar, SAPIR bandwidth: broad), C (diffusion scheme:Monopolar,SAPIR bandwidth:broad, PACE continous sat), D (diffusion scheme:flow comp,SAPIR bandwidth:broad, PACE continous sat) by using a iShim (integrated shimming) sequence at 3.0 T. The parameters of signal-to-noise ratio (SNR), contrast to noise ratio(CNR), liver and spleen ADC values were calculated. To evaluate the homogeneity of fat suppression and the degree of the fat suppression, the variation of the signal intensity of subcutaneous fat area (SIvar) at four directions and the average difference between the T2WI and DWI sequence of the signal intensity of subcutaneous fat area (SId) were calculated. The above quantitative parameters were compared with Repeated Measures ANOVA and a bonferroni adjustment was applied for multiple comparisons. The degree of ghosts and whole image quality were scored by two radiologists with more than 10 years experience independently on the basis of subjective five-point image quality scales and the subjective quality score (SQS) were compared with Friedman signed rank test. A P<0.05 indicate statistically significant difference.Result:Although the CNR values decreased from Group D to A (18.64±18.470, 14.16±12.778, 11.89±11.546, 11.10±9.053 ), no significant difference was found(P>0.050). The SIvar and SId were higher in Group D ([(11.60±7.060)% , (82.44±29.854)%)and Group C ([(10.09±5.866)% , (83.28±32.486)%) than Group A ([(7.45±2.971)% , (25.96±7.171)%) and Group B ([(7.12±2.544)% , (34.67±12.724)%), and the difference among them was statistically significant(P<0.001) . The SQS increased from Group A to Group D (1.83±0.778, 2.17±0.582, 2.60±0.800, 3.67±0.471) with a significant difference (P<0.001). No significant difference was found for SNR (96.41±25.360,94.45±26.319,92.52±27.782,90.99±30.335), liver’s ADCs[(1.29±0.024)×10-3 mm 2/s, (1.30±0.023)×10-3 mm 2/s, (1.30±0.0250)×10-3 mm 2/s, (1.30±0.026)×10-3 mm 2/s] from Group A to Group D. Conclusion:The continuous fat suppression technique and Broad SPAIR Pulse can increase the fat saturation efficiency and decrease the ghost artifacts, when combined with flow compensation technique, the image quality can be further improved without affect ADC values.

Acknowledgements

No acknowledgement found.

References

[1]Nummine K,JCAT;2003[2]Bangerter NK,MRM;2004[3]Casselman JW,Neuroradiology;1996[4]Kellman P,MRM;2009[5]Stanisz GJ,MRM 54;2005

Figures

Figure 1.The ghost artifacts (indicated by arrows) decreased from Group A to D. The homogeneity and degree of fat saturation increased from Group A to D. The subjective quality score (SQS) was 1, 2, 3, 4 for Group A to D.

Figure 2. The Whiskers Box of SQS, The SQS in creased from Group A to D, which with a statistical significant difference(p<0.05). Note: SQS. subjective quality score.

Figure 3. Bar graphs show the standard deviation of signal intensity in subcutaneous fat area between T2WI TSE and iShim DWI sequence.The SIvar and SId were higher in Group D and Group C than Group A and Group B, and the difference among them was statistically significant(P<0.001) .



Proc. Intl. Soc. Mag. Reson. Med. 24 (2016)
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