01.10.2013 | Head and Neck | Ausgabe 10/2013
Intravoxel incoherent motion MR imaging: comparison of diffusion and perfusion characteristics between nasopharyngeal carcinoma and post-chemoradiation fibrosis
- Vincent Lai, Xiao Li, Victor Ho Fun Lee, Ka On Lam, Queenie Chan, Pek Lan Khong
To compare the intravoxel incoherent motion (IVIM) diffusion and perfusion characteristics of nasopharyngeal carcinoma (NPC) and post-chemoradiation fibrosis to aid in their differentiation.
Fifty-three (64 %) patients with newly diagnosed NPC and 30 (36 %) patients with biopsy-proven post-chemoradiation fibrosis were recruited into tumour and fibrosis groups respectively. Diffusion-weighted magnetic resonance (MR) imaging was performed using 13 b values (0–1,000 s/mm2). Their respective IVIM parameters (D, pure diffusion; f, perfusion fraction; D*, pseudodiffusion coefficient) were obtained.
D and f were significantly lower in NPC (D = 0.752 ± 0.194 × 10-3 mm2/s, P <0.001; f = 0.122 ± 0.095, P <0.001) than in fibrosis (D = 1.423 ± 0.364 × 10-3 mm2/s; f = 0.190 ± 0.120); while D* was significantly higher in NPC (111.366 ± 65.528 × 10-3 mm2/s, P <0.001) than in fibrosis (77.468 ± 62.168 × 10-3 mm2/s). Respective cut-off values with sensitivity, specificity and accuracy were: D = 1.062 × 10-3 mm2/s (100 %, 100 %, 100 %); f = 0.132 (66.0 %, 100 %, 78.3 %); D* = 85.283 × 10-3 mm2/s (100 %, 90.7 %, 96.4 %).
NPC and post-chemoradiation fibrosis have distinctive IVIM parameters. IVIM MR imaging is potentially useful in discrimination between NPC and fibrosis.
• New MRI techniques offer greater help in the assessment of nasopharyngeal carcinoma.
• Tumour and post-chemoradiation fibrosis have distinctive intravoxel incoherent motion diffusion/perfusion parameters.
• Non-invasive IVIM MRI may help differentiate between tumour and fibrosis.
• Pure diffusion is a robust independent discriminating factor which improves diagnostic confidence.