Diffusion-Weighted Imaging of the Head and Neck: Influence of Fat-Suppression Technique and Multishot 2D Navigated Interleaved Acquisitions

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Fig 1.
Fat-suppression uniformity of DWI. A 49-year-old man underwent MR imaging for staging of left maxillary sinus cancer (A, post-contrast-enhanced T1WI, arrow). On ssEPI-STIR (B), fat suppression is homogeneous without disrupting the original mass (arrow). On ssEPI-SPIR (C), unsuppressed fat signal (arrows) in the subcutaneous layer creates ghost artifacts that obscure the original mass, making the lesion assessment unfeasible. Unlike ssEPI-SPIR, unsuppressed fat signal (arrow) does not shift much to cover the mass on msEPI-SPIR (D).
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Fig 2.
Image distortion of DWI. An 85-year-old man underwent MR imaging for the evaluation of a left premaxillary abscess (A, post-contrast-enhanced T1WI, arrow). Image distortion is increased on ssEPI-STIR (B, arrow) and ssEPI-SPIR (C, arrow) and decreased on msEPI-SPIR (D, arrow). The left premaxillary abscess is not distorted by the susceptibility artifacts only on msEPI-SPIR.

Table 1:

Quantitative assessment of DWI^{^a}

	ssEPI-STIR	ssEPI-SPIR	msEPI-SPIR	P Values^{^b}
CNR
Pons	4.45 ± 0.84	8.29 ± 1.62	7.69 ± 1.90	.001/.001/.022
Cerebellar white matter	3.86 ± 0.73	8.78 ± 1.53	8.52 ± 2.13	.001/.001/.294
Parotid gland	0.43 ± 0.41	1.21 ± 0.68	1.74 ± 0.82	.001/.001/.001
Lymph node	4.55 ± 1.59	6.61 ± 2.02	7.06 ± 2.56	.001/.001/.104
Palatine tonsil	4.46 ± 2.47	6.37 ± 2.27	6.55 ± 2.12	.001/.001/.61
Semispinalis muscle	0.40 ± 0.22	0.87 ± 0.31	1.00 ± 0.50	.001/.001/.05
ADC (× 10⁻³ mm²/s)
Pons	0.737 ± 0.042	0.743 ± 0.033	0.799 ± 0.083	.236/.001/.001
Cerebellar white matter	0.636 ± 0.039	0.655 ± 0.030	0.691 ± 0.061	.001/.001/.001
Parotid gland	0.771 ± 0.170	0.867 ± 0.147	0.907 ± 0.141	.001/.001/.001
Lymph node	0.900 ± 0.321	0.915 ± 0.349	1.028 ± 0.341	.300/.001/.001
Palatine tonsil	0.753 ± 0.325	0.748 ± 0.321	0.846 ± 0.310	.818/.001/.001
Semispinalis muscle	0.881 ± 0.187	1.118 ± 0.115	1.360 ± 0.107	.001/.001/.001

↵a Data are given as mean ± SD.
↵b P values are derived from pair-wise comparison using a paired t test with a Bonferroni correction among ssEPI-STIR and ssEPI-SPIR/ssEPI-STIR and msEPI-SPIR/ssEPI-SPIR and msEPI-SPIR.