Investig Magn Reson Imaging.  2016 Mar;20(1):44-52. 10.13104/imri.2016.20.1.44.

Improvement of Fat Suppression and Artifact Reduction Using IDEAL Technique in Head and Neck MRI at 3T

• Hong JH
• Lee HY
• Kang YH
• Lim MK
• Kim YJ
• Cho SG
• Kim MY

• KMID: 2161369
• DOI: http://doi.org/10.13104/imri.2016.20.1.44

Abstract

PURPOSE
To quantitatively and qualitatively compare fat-suppressed MRI quality using iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) with that using frequency selective fat-suppression (FSFS) T2- and postcontrast T1-weighted fast spin-echo images of the head and neck at 3T.
MATERIALS AND METHODS
The study was approved by our Institutional Review Board. Prospective MR image analysis was performed in 36 individuals at a single-center. Axial fat suppressed T2- and postcontrast T1-weighted images with IDEAL and FSFS were compared. Visual assessment was performed by two independent readers with respect to; 1) metallic artifacts around oral cavity, 2) susceptibility artifacts around upper airway, paranasal sinus, and head-neck junction, 3) homogeneity of fat suppression, 4) image sharpness, 5) tissue contrast of pathologies and lymph nodes. The signal-to-noise ratios (SNR) for each image sequence were assessed.
RESULTS
Both IDEAL fat suppressed T2- and T1-weighted images significantly reduced artifacts around airway, paranasal sinus, and head-neck junction, and significantly improved homogeneous fat suppression in compared to those using FSFS (P < 0.05 for all). IDEAL significantly decreased artifacts around oral cavity on T2-weighted images (P < 0.05, respectively) and improved sharpness, lesion-to-tissue, and lymph node-to-tissue contrast on T1-weighted images (P < 0.05 for all). The mean SNRs were significantly improved on both T1- and T2-weighted IDEAL images (P < 0.05 for all).
CONCLUSIONS
IDEAL technique improves image quality in the head and neck by reducing artifacts with homogeneous fat suppression, while maintaining a high SNR.

Keyword

IDEAL; Fat saturation; Head and neck MR; Susceptibility artifact; Metallic artifact

MeSH Terms

Artifacts*
Ethics Committees, Research
Head*
Lymph Nodes
Magnetic Resonance Imaging*
Mouth
Neck*
Pathology
Prospective Studies
Signal-To-Noise Ratio
Water
Water

Figure

• 

  Fig. 1 MR images in a 56-year-old man with gingival cancer. Frequency selective fat suppressed T2- (a) and postcontrast T1-weighted (b) axial images show susceptibility artifacts identified as signal loss at the headneck junction (arrows), obscuring normal anatomy. Corresponding IDEAL fat suppressed T2- (c) and T1-weighted (d) axial images show markedly less severe susceptibility artifacts and homogeneous fat suppression at the head-neck junction (arrows).

• 

  Fig. 2 MR images in a 47-year-old woman with paraganglioma. Frequency selective fat suppressed T2- (a) and postcontrast T1-weighted (b) images show metallic artifact, arising from a metallic crown identified as rim of high signal intensity (short arrows) and an area of low signal intensity (arrowheads) around the right anterior mandible body, obscuring adjacent gingiva, lip, and floor of mouth, and failed fat suppression. Marked reduction of metallic artifacts and homogeneous fat suppression are identified on corresponding IDEAL fat suppressed T2- (c) and T1-weighted (d) images (long arrows), improving the visibility of the surrounding anatomy.

• 

  Fig. 3 MR images in a 66-year-old man with buccal cancer. Areas of signal loss are seen around paranasal sinuses (arrows) due to susceptibility artifacts on frequency selective fat suppressed T2- (a) and T1-weighted (b) images. Corresponding IDEAL fat suppressed T2- (c) and T1-weighted (d) images show less severe susceptibility artifacts and improved visibility of the anatomy surrounding paranasal sinuses (arrows).

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