MR-driven metal artifact reduction in PET CT

• Published in: Physics in medicine & biology Vol. 58; no. 7; pp. 2267 - 2280
• Main Authors: Delso, G, Wollenweber, S, Lonn, A, Wiesinger, F, Veit-Haibach, P
• Format: Journal Article
• Language: English
• Published: England IOP Publishing 07.04.2013
• Subjects: Dental Implants; Humans; Magnetic Resonance Imaging; Metals; Multimodal Imaging - methods; Neoplasms - diagnostic imaging; Positron-Emission Tomography; Retrospective Studies; Tomography, X-Ray Computed
• ISSN: 0031-9155; 1361-6560
• DOI: 10.1088/0031-9155/58/7/2267

Among the proposed system architectures capable of delivering positron emission tomography/magnetic resonance (PET MR) datasets, tri-modality systems open an interesting field in which the synergies between these modalities can be exploited to address some of the problems encountered in standalone systems. In this paper we present a feasibility study of the correction of dental streak artifacts in computed tomography (CT)-based attenuation correction images using complementary MR data. The frequency and severity of metal artifacts in oncology patients was studied by inspecting the CT scans of 152 patients examined at our hospital. A prospective correction algorithm using CT and MR information to automatically locate and edit the region affected by metal artifacts was developed and tested retrospectively on data from 15 oncology patients referred for a PET CT scan. In datasets without malignancies, the activity in Waldeyer's ring was used to measure the maximum uptake variation when the proposed correction was applied. The measured bias ranged from 10% to 30%. In datasets with malignancies on the slices affected by artifacts, the correction led to lesion uptake variations of 6.1% for a lesion 3 cm away from the implant, 1.5% for a lesion 7 cm away and <1% for a lesion 8 cm away.