Objective

To evaluate the imaging quality of the trigeminal nerve between controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) accelerated 3D constructive interference in the steady state (3D-CISS) and conventional CISS that without acceleration factors under the same imaging parameters at 3.0T.

Methods

Fourteen normal volunteers (female: male: 6: 8, mean age: 24 ±1.04) were examined with 3D-CISS and CAPIRINHA- accelerated CISS sequences at 3.0 T scanner (MAGNETOM Spectra, Siemens AG, Erlangen, Germany). The scan parameters are shown in table 1. In order to quantitative analysis the image quality of CAIPIRINHA- accelerated CISS sequence and traditional 3D CISS sequence, two radiologists with 10 years working experience in neurology measured the signal intensity of trigeminal nerve and pons, and calculated the signal noise ratio (SNR) and the contrast to noise ratio (CNR) of the trigeminal nerve，and then the subjective score of images on trigeminal nerve details displaying, the quality of peripheral anatomy and the degree of artifact based on CAIPIRINHA- accelerated CISS and 3D-CISS sequence were evaluated by the same two radiologists according to a three-point method (1: anatomical structure can be shown, but the image is blurry and cannot be used for diagnosis; 2: the anatomic structure is partly fuzzy but the image can be used for diagnosis; 3: the edge of anatomic structure is shown clearly, no artifact). The agreement of two readers was evaluated by Kappa test (k<0.20, poor; 0.21–0.40, fair; 0.41–0.60,moderate; 0.61–0.80, good; and 0.81–1.00, excellent).All the quantitative indexes were tested by paired-samples t test and the qualitative indexes were tested by Wilcoxon signed ranks test using SPSS software 18.0 (SPSS, Chicago, IL )， P value<0.05 was considered statistically significant difference.

Results

No significant differences of SNR was found between traditional 3D-CISS and CAIPIRINHA- accelerated 3D CISS [(66.32±20.91) vs (59.81±18.80)，P=0.118]；The differences of CNR were also not significant between traditional 3D-CISS and CAIPIRINHA- accelerated 3D CISS [(8.29±15.29) vs (11.53±10.71)，P=0.814]. The subjective evaluation scores of both readers didn’t show significant differences (table 2). Interobserver agreement of image quality has good consistency (K=0.80).

Conclusion

Compared to conventional 3D-CISS, CAIPIRINHA- accelerated CISS sequence can significantly shorten the scanning time without affecting the image quality under the same scanning parameters at 3.0T.

Discussion

With the development of MR technology, it is of great help to diagnose the etiology of trigeminal neuralgia caused by vascular compression. Most of the patients with trigeminal neuralgia cannot insist on long scanning, and the weak exercise of the patient can significantly reduce the image quality. This requires that the scanning time be shortened without affecting the image quality in the scanning process. The recently emerging CAIPIRINHA- accelerated 3D CISS as an optimized parallel acquisition technique, can significantly decrease scanning time under the premise of guaranteeing the image quality.

Acknowledgements

No acknowledgement found.

References

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