Artikel
Implant-specific follow-up imaging of treated intracranial aneurysms: TOF-MRA vs. metal artifact reduced intravenous flatpanel detector (FP) CTA
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Veröffentlicht: | 8. Juni 2016 |
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Objective: Platinum coils and clips impair the image quality in CTA and MRA. Metal artifact reduction (MAR) reduces hardening artifacts in FP-CTA datasets. The aim was to compare the diagnostic quality of TOF-MRA and MAR-FP-CTA and to determine the imaging modality best suited for evaluation of endovascularly and surgically treated aneurysms.
Method: The image quality of MRA and MAR-FP-CTA of 25 patients with intracranial implants (coiling: n=20; clipping: n=15; stent-assisted coiling: n=9) was evaluated by two independent readers. MAR-FP-CTA using a Dyna-CT protocol (20 sec scan time, 496 projections, intravenous contrast material; Artis Zee, Siemens, Forchheim) was compared with MRA-images (1.5 or 3.0 T MR scanner). Nominal data were analyzed using McNemar's Chi-Square test and ordinal variables using the Wilcoxon rank test.
Results: To detect potential residual aneurysms and to evaluate the parent vessel, MAR-FP-CTA was significantly better suited for clipped aneurysms (p <0.01). In patients with larger coil packages (>160 mm3) TOF-MRA allowed for better assessability when compared to MAR-FP-CTA (P <0.01). In patients with small coil packages (<160 mm3) there was no significant difference between TOF-MRA and MAR-FP-CTA. For different clip sizes no significant difference regarding the assessability of images were found. The interobserver comparison showed a high correlation.
Conclusions: For follow-up imaging of clipped aneurysms MAR-FP-CTA is better suited than TOF-MRA. For small (<160 mm3) coil packages there was no significant difference regarding the assessability using MAR-FP-CTA and TOF-MRA. For large (>160 mm3) coil packages, however, TOF-MRA was significantly better suited than MAR-FP-CTA.