High-resolution MRI of the human parotid gland and duct at 7 Tesla.

Full Abstract

OBJECTIVES: MR techniques have been reported as an alternative to conventional sialography. High-field systems (7 T) provide new contrasts coupled with increased signal-to-noise ratio, and hence higher spatial resolution. To our knowledge, no measurements of the parotid gland at 7 T have been reported. Therefore, our study aimed to optimize sequences for high-field MR imaging of the parotid gland and duct, as well as the facial nerve at 7 T and show the potential of high field imaging. MATERIALS AND METHODS: A 7 T whole-body scanner was used together with a 10-cm-diameter loop coil. Various GRE (MEDIC, DESS) and TSE (PD/T2, STIR) sequences were optimized and subsequently tested on 4 healthy volunteers and 4 patients. High-resolution images were compared with 1.5 T images both quantitatively (signal-to-noise ratio, contrast-to-noise) and qualitatively (visual rating of 2 independent readers). RESULTS: The high 0.6 mm isotropic resolution of the 3D DESS sequence was very useful for defining an oblique orientation with most of the duct being in-plane for subsequent imaging. With the MEDIC sequence, very fine branches of the duct were visible; furthermore, MEDIC yielded a very good depiction of lymph nodes. Severe specific absorption rate problems were observed with the STIR sequence at 7 T. Gland tissue in tumor patients can be well characterized with the PD/T2 TSE. Highest contrast-to-noise between duct and gland was achieved with the 7 T DESS. At 1.5 T, only the STIR sequence showed comparable quality to the overall superiority of the 7 T sequences. The facial nerve could only be depicted close to the skull base. CONCLUSION: MR imaging at 7 T provides excellent image contrast and resolution of the parotid gland and duct. The proposed protocol offers a noninvasive examination within about 30 minutes.

Author information

Author/s: Kraff, Oliver (O); Theysohn, Jens M (JM); Maderwald, Stefan (S); Kokulinsky, Patrick C (PC); Dogan, Zeynel (Z); Kerem, Alexander (A); Kruszona, Stefan (S); Ladd, Mark E (ME); Gizewski, Elke R (ER); Ladd, Susanne C (SC);

Affiliation: Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany. oliver.kraff(-atsign-)uni-due.de

Journal and publication information

Publication Type: Journal Article

Journal: Investigative radiology (Invest Radiol), published in United States. (Language: eng)

Reference: 2009-Sep; vol 44 (issue 9) : pp 518-24

Dates: Created 2009/08/20; Completed 2009/11/05;

PMID: 19652615, status: MEDLINE (last retrieval date: 11/5/2009, IMS Date: )

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