Arjen Lindenholz

82 CHAPTER 4 Abstract Background and Purpose: Intracranial vessel wall MRI plays an increasing role in diagnosing intracranial vascular diseases. For a complete assessment, pre- and postcontrast sequences are required and, including other sequences, this results in a long scan duration. Ideally, the scan time of the vessel wall sequence should be reduced. The purpose of this study was to evaluate different intracranial vessel wall sequence variants to reduce scan duration, provided an acceptable image quality can be maintained. Materials and Methods: Starting from the vessel wall sequence that we use clinically (6minutes 42 seconds), 6 scan variants were tested (scan duration ranging between 4 minutes 39 seconds to 8 minutes 24 seconds), creating various trade-offs among spatial resolution, signal-to-noise-ratio (SNR) and contrast-to-noise-ratio (CNR). In total, 15 subjects were scanned on a 3T MRI scanner; in 5 subjects all 7 variants were performed precontrast-only and in 10 other subjects, the fastest variant (4 minutes 39 seconds) and our clinically used variant (6 minutes 42 seconds) were performed pre- and postcontrast. Results: The fastest variant (4 minutes 39 seconds) had higher or comparable SNRs/CNRs of the intracranial vessel walls compared with the reference sequence (6 minutes 42 seconds). Qualitative assessment showed cerebrospinal fluid was most suppressed in the fastest variant of 4 minutes 39 seconds and the variant of 6 minutes 42 seconds. Pre- and postcontrast, SNRs/CNRs of the fastest variant were all, except one, higher compared with the variant of 6 minutes 42 seconds (p < 0.008). Furthermore, the fastest variant (4 minutes 39 seconds) detected all vessel wall lesions identified on the 6 minutes 42 seconds variant. Conclusions: A 30% faster vessel wall sequence was developed with high SNRs/ CNRs that resulted in good visibility of the intracranial vessel wall.