Comparison of 3D constructive interference in steady state (CISS) and T2 sampling perfection with application optimized contrasts using different flip angle evolution MR imaging of the intracranial trigeminal nerve and central skull base neuroforamina.

BACKGROUND AND PURPOSE: Due to surgical advancements, the accurate detection of perineural disease spread has become increasingly important in the management and prognostication of head and neck cancers, though MR evaluation has thus far been limited by technical and logistic challenges. The purpose of this study was to specifically evaluate the relative capability of 3D CISS and 3D T2-SPACE imaging to delineate the proximal intracranial divisions of the normal trigeminal nerve, an area important in determining the resectability of intracranial perineural disease. MATERIALS AND METHODS: A single center HIPAA-compliant, IRB approved retrospective review of 40 patients with clinical temporal bone/internal auditory canal MR imaging was conducted. 20 patients with 3D CISS images and 20 patients with 3D T2-SPACE images met inclusion criteria. Two radiologists scored the sequences on a 3-point scale based on ability to visualize anatomic structures surrounding the trigeminal nerve in Meckel's cave, intracranial trigeminal divisions, skull base neuroforamina, and proximal extracranial mandibular division. RESULTS: The following anatomic locations scored significantly better in the T2-SPACE sequence compared to the CISS sequence for both raters: intracranial V3 (p < .05), foramen ovale (p < .05), and extracranial V3 (p < .01). The average scores for the anterior Meckel's cave and foramen rotundum were higher for the T2-SPACE sequence, although not significantly. Percent interobserver agreement ranged from 50 to 90% and 65-100% for the different anatomic locations on the CISS and T2-SPACE sequences, respectively. CONCLUSION: 3D T2-SPACE was found to be superior to 3D CISS in the evaluation of the distal intracranial and extracranial portions of the normal trigeminal nerve.

Standardizing Magnetic Resonance Imaging Protocols Across a Large Radiology Enterprise: Barriers and Solutions.

PURPOSE: Standardization of magnetic resonance imaging protocols is important to achieve reproducible and effective outcomes across a large volume of patient examinations. It also ensures a consensus-driven approach to imaging, while reducing inefficient workflow practices. This article details our approach and experience with implementing systematic methods to address obstacles, and instituting a protocol strategy from development to installation to feedback. METHODS: A collaborative planning and implementation strategy was derived to address and centralize protocol standardization for 25 MRI systems across 14 imaging centers. In addition to establishing radiologist-lead working groups to define clinical need for each division, we enlisted MR physicists to work with sites to outline system capability and recommend best practices for each protocol method. The strategy also involved protocol alternatives due to patient type, and steps to ensure image quality feedback mechanisms. RESULTS: We found that a collaborative team of radiologists, physicists, and technologists is vital for creating structured and categorized protocols that balances clinical need and accepted standards, with system technical capability and exam time limitations. A formalized protocol document and numbering system was created to allow efficient order-to-protocol assignment and selection. Consideration for other variables, such as patient type, user education, and automated tasks, further extend protocol usability and standardization in clinical practice. CONCLUSIONS: MRI protocol standardization is a significant challenge within a large institution, which requires ongoing oversight and improvement. An organized committee of stakeholders, incorporating clinical, technical, and site-specific expertise, is an important first step to understand the current state and direct standardization goals.