Yanqiu Lv1, Hua Cheng1, Ningning Zhang1, Kaining Shi2, Guangheng Yin1, Di Hu1, Huiying Kang1, Xiaojuan Tao1, Feng Guan1, Yang Wen1, and Yun Peng1
1Beijing Children's Hospital Affiliated To Capital Medical University, Beijing, China, People's Republic of, 2Imaging systems Clinical Science,Philips Healthcare, Beijing, China, People's Republic of
Synopsis
Comparing the performance of 3D T1W-WATS sequence with 2D T2*W FFE sequence in the evaluation of cartilage damage in Pediatric hemophilia joints. 16 hemophiliac joints including 8 knees and 8 ankles were scanned on a 3.0 T, signal to noise of Cartilage, relative contrast between cartilage and surrounding tissue and the impact of hemosiderin were employed to compare.Our result showed that 3D T1W-WATS sequence had better relative contrast between cartilage and surrounding tissues and the immunity to hemosiderin compared with 2D T2*W sequence.3DT1W-WATS sequence can be performed in the evaluation of cartilage damage in hemophilia patients.Introduction
Which kind of sequence is best and optimum for cartilage imaging depends on disease type and research focus.2D T2*W FFE sequence has been employed routinely to assess the cartilage of hemophiliac joint in clinical practice,as suggested by Rand et al1. However, the evaluation of cartilage may be affected in severe hemophilia patients due to the sensitivity to hemosiderin of T2*W FFE sequence. 3DT1W-WATS is a gradient echo sequence with the water-selective selective excitation to achieve high signal to noise , high spatial resolution and better contrast between cartilage and surrounding tissues. The purpose of this study is to compare the performance of 3DT1W-WATS sequence with 2D T2*W FFE sequence in evaluation of cartialge damage in pediatric hemophilic joints.
Materials and Methods
16 joints including 8 knees and 8 ankles (13 joints with hemosiderin deposition) from 16 hemophiliac joints from16 hemophilia patients (males,age 9-17 years old) were scanned on a 3.0 T ( Achieva, Philips Healthcare, Best, The Netherlands) with sagittal 3DT1W-WAS sequence (TR/TE/FA= 20ms/6ms/150, thickness/gap=3.0mm/-1.5mm, FOV=160mm, matrix=420*420, scan time=7minutes 25 seconds) and 2D T2* FFE sequence (TR/TE/FA=422ms/12ms/200, thicknesss/gap=3mm/0.5mm, FOV=160mm,matrix=304*253,scan time=2 minutes 54 seconds). Post-process was performed on the Extended Workspace(R2.6.3,Philips). Signal to noise (SNR) and relative contrast between cartilage and surrounding tissues were employed to measure the performance of two sequences quantitatively:
$$SNRa=SIa/SDnoise$$
$$ReConab=(SIa−SIb)/(SIa+SIb)$$
where SIa and SIb mean signal intensity of tissue a and b,SDnoise means standard deviation of noise,ReCon ab means relative contrast between tissue a and b. Three ROIs were drawn on each structure, and the mean value of ROIs was used for caculation (Fig.1.).
Lateral and medial slices near to hemosiderin were selected in very joint, cartilage of 13 joints with hemosiderin deposition were diveded into 142 subareas referring method of Peterfy2 et al and Jundmann3 et al (Fig.2.). The impact of hemosiderin deposition was evaluated by counting the number of subareas where the display of cartilage was affected. SNR of 3DT1W-WATS sequence and 2D T2* FFE sequence was compared using non parameters Wilcoxon rank test, and relative contrast was compared by t test.Fisher exact test was performed to analyze the difference of hemosiderin-affected subareas numbers between two sequences.
Result
There was no statistical difference for
SNR between 3D T1W-WATS sequence and 2D T2* FFE sequence(P>0.05)(Table 1.) 3D T1W-WATS sequence exhibited better relative contrast between cartilage and bone marrow, cartilage and fat, cartilage and fluid than 2D T2* FFE sequence( P<0.05)(Table 1.) 42 of 142 subareas of cartilage were covered with hemosiderin partially and completely in 2D T2* FFE sequence, while the number was 16 in 3D T1W-WATS sequence (P<0.05). 2D T2* FFE sequence still had a better relative contrast between cartilage and hemosiderin (P<0.05).
Conclusion
3D T1W-WATS seuqence can be performed in the evaluation of cartilage damage in hemophila patients, with better relative contrast between and immunity to hemosiderin deposition compared with 2D T2* FFE seuqence.
Acknowledgements
No acknowledgement found.References
1.Rand T, Trattnig S, Male C et al. Magnetic resonance imaging in hemophilic children: Value of gradient echo and contrast-enhanced imaging. Magn Reson Imaging 1999; 17: 199-205.
2. Peterfy CG, Gnermazi A, Zaim S, et al. Whole-Organ Magnetic Resonance Imaging Score(WORMS) of the knee in osteoarthritis. Osteoarthr Catil,2004,12:177-190.
3.Jungmanna PM. , Thomas B., Schaeffeler C.et al. 3.0 T MR imaging of the ankle: Axial traction for morphological cartilage evaluation, quantitative T2 mapping and cartilage diffusion imaging- A preliminary study. Eur J Radiol,2015,84(8):1546-54.