British Journal of Radiology (2004) 77, 641-647
© 2004 British Institute of Radiology
doi: 10.1259/bjr/31774546
Contrast-enhanced MRI of the menisci of the knee using ultrashort echo time (UTE) pulse sequences: imaging of the red and white zones
P D Gatehouse, PhD
1
T He, PhD
2
B K Puri, PhD
3
R D Thomas, FRCS
2
D Resnick, MD
4 and
G M Bydder, FRCR
4
1 The Cardiac Magnetic Resonance Unit, Royal Brompton Hospital, Sydney Street, London SW3 6NP, 2 The Department of Surgery and the 3 Imaging Sciences Department, MRC Clinical Sciences Centre, Imperial College Faculty of Medicine, Hammersmith Hospital, Du Cane Road, London W12 0HS, UK and the 4 Department of Radiology, University of California, San Diego, USA
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Figure 1. Diagram of the menisci of the knee seen in cross section. The central avascular white zone is shown as white, and the vascular red zone as dark.
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Figure 2. A 21-year-old man with normal menisci: (a) Pre ultrashort echo time (UTE), (b) post UTE, (c) pre TE=5.95 ms echo image, (d) post TE=5.95 ms image, (e) pre difference image (c subtracted from a) and (f) post difference image (d subtracted from b). In (a) the menisci and the outer layer of the articular cartilage are almost isointense. Joint fluid has a slightly lower signal. In (c) the menisci are seen as low signal areas with the outer aspects slightly lower in signal intensity. In (e) (the subtracted image) the menisci are seen with moderate signal intensity with slightly higher signal on their outer aspects. In (b) enhancement is seen but it is not possible to define the extent of the menisci. In (d) the menisci are of low signal except for a small linear area (arrow) with features consistent with a collagen tie. In (f) generally higher signal is seen in the menisci together with obvious enhancement (arrows). This area of enhancement was designated the intermediate region, the lower signal area within the meniscus central to it was designated as the central region and the area just peripheral to it was designated as the peripheral region. Regions of interest were then placed in these regions on (f) and transferred to (b) and (c) etc. for corresponding measurements of signal intensity.
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Figure 3. Plot of mean (±standard deviation) signal intensity against echo time (TE) (a) before and (b) after contrast administration for the central region. The differences in pre- and post-enhancement signal intensity were significant at each TE (p<0.001). The differences in signal intensity are greatest at the shortest TE. There is an increase in signal in (b) following contrast administration (46% at TE=0.08 ms).
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Figure 4. Plot of mean signal intensity against echo time (TE) (a) before and (b) after contrast enhancement for the intermediate region. The differences in signal intensity are significant at each TE (p<0.001) with the greatest at the shortest TE. There is a marked increase in signal in (b) (76% at TE=0.08 ms).
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Figure 5. Plot of mean signal intensity against echo time (TE) (a) before and (b) after contrast enhancement for the peripheral region. The differences in signal intensity were significant at each TE (p<0.001) with the greatest at the shortest TE. There was an obvious increase in signal in (b) (86% at TE=0.08 ms).
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Figure 6. Mean difference in signal intensity (echo time (TE)=0.08 ms minus TE=5.95 ms images) for central, intermediate and peripheral regions pre (lower) and post (upper) contrast administration. The intermediate region shows a slightly higher signal intensity than the other two regions before enhancement (lower). This becomes greater after enhancement (upper). These signal intensity values parallel the appearances shown in Figure 2f .
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Copyright © 2004 by the British Institute of Radiology.
