Clinical Scorecard: Effects of Various Metal Artifact Reduction Methods on Photon-Counting CT Scans of the Head and Neck in Patients with Dental Implants

At a Glance

Key Highlights

• Metal artifacts in CT imaging impair diagnostic accuracy by obscuring relevant findings such as abscesses, fractures, or malignancies.
• Photon-counting detector CT (PCD-CT) enables direct photon counting and energy measurement, allowing advanced artifact reduction techniques.
• Combination of iterative metal artifact reduction (iMAR) and high keV virtual monoenergetic imaging (140 keV) on PCD-CT improves subjective and objective image quality.

Guideline-Based Recommendations

Diagnosis

• Use PCD-CT imaging for patients with dental implants requiring craniofacial CT to improve image quality.
• Apply qualitative assessment of artifact severity and anatomical delineation using standardized Likert scales.

Management

• Implement iterative metal artifact reduction (iMAR) algorithms optimized for PCD-CT spectra to reduce beam hardening and sinogram artifacts.
• Utilize virtual monoenergetic imaging at high energy levels (140 keV) to further reduce metal artifacts.
• Combine iMAR with 140 keV monoenergetic reconstruction for optimal artifact reduction.

Monitoring & Follow-up

• Perform blinded, independent qualitative image assessments by radiologists to evaluate artifact severity and anatomical delineation.
• Monitor image quality improvements with each reconstruction method to guide clinical imaging protocols.

Risks

• Consider contraindications for CT imaging such as iodine contrast allergy, renal impairment, and thyroid dysfunction before scanning.
• Be aware that metal artifacts may still obscure findings despite reduction techniques; clinical correlation remains essential.

Patient & Prescribing Data

Adults (≥18 years) with dental hardware undergoing contrast-enhanced craniofacial PCD-CT imaging for clinical indications (e.g., oropharyngeal carcinoma, abscesses, lymph node metastasis).

Use of iMAR and high keV monoenergetic reconstructions on PCD-CT improves visualization of anatomy adjacent to dental implants, potentially enhancing diagnostic confidence.

Clinical Best Practices

• Ensure patient eligibility by screening for contraindications to CT and contrast agents.
• Acquire PCD-CT scans in portal-venous phase with body weight-adapted contrast dosing.
• Reconstruct images using standard (60 keV), high keV (140 keV), iMAR, and combined iMAR + 140 keV techniques for comparative evaluation.
• Use iterative metal artifact reduction algorithms specifically optimized for PCD-CT spectra.
• Perform multi-reader qualitative assessments to validate image quality improvements.

References

• Anhaus et al 2022 on virtual monoenergetic imaging
• Siemens Healthineers iMAR algorithm description
• Photon-counting detector CT technology overview
• NORA Imaging software