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Erschienen in:
01.10.2013 | Head and Neck
Intravoxel incoherent motion MR imaging: comparison of diffusion and perfusion characteristics between nasopharyngeal carcinoma and post-chemoradiation fibrosis
Erschienen in: European Radiology | Ausgabe 10/2013
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Objectives
To compare the intravoxel incoherent motion (IVIM) diffusion and perfusion characteristics of nasopharyngeal carcinoma (NPC) and post-chemoradiation fibrosis to aid in their differentiation.
Methods
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.
Results
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 %).
Conclusion
NPC and post-chemoradiation fibrosis have distinctive IVIM parameters. IVIM MR imaging is potentially useful in discrimination between NPC and fibrosis.
Key Points
• 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.