Timing Parameters	Series 1	Series 2	Series 3	Series 4	Series 5	Series 6
	Coronal T1 SE	Sagittal PD FSE-XL	Sagittal T2 FSE-XL FS	Coronal T2 FSE-XL FS	Axial PD FSE-XL	Sagittal 3D-SPGR
TR/TE	800/min full	4000/min full	4000/72	4000/72	4000/min full	31/15
ETL	—	6	8	8	8	—
Flip Angle	—	—	—	—	—	30
RBW	21 kHz	21 kHz	21 kHz	21 kHz	21 kHz	—
FOV	16 cm	16 cm	16 cm	16 cm	14 cm	14 cm
Matrix	512 x 192	512 x 192	256 x 192	512 x 192	256 x 192	256 x 192
Slice Thickness	4mm	3mm	3mm	4mm	4mm	28 sl/1.5 mm
Interslice Gap	1mm	1mm	1mm	1mm	1mm	0
NEX	2	2	2	2	2	2
Acquisition Time	5:17	4:16	3:12	3:12	3:12	6:25
Fat Sat	no	no	yes	yes	no	no
No Phase Wrap	yes	yes	yes	yes	yes	yes
EDR	no	no	no	no	no	yes
Freq	S/I	A/P	A/P	S/I	A/P	A/P

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All of the imaging techniques described in the next sections are optimized for the Signa Horizon LX scanner with EchoSpeed gradients running software version 8.2.5. All of the sequences take advantage of the No Phase Wrap (NPW) option to reduce the chance of phase wrap artifact. The variable bandwidth (VB) option is useful to allow imaging with a 512 matrix without increasing scan time. The extended dynamic range (EDR) option is useful in the 3D imaging sequences to provide the best visualization of cartilage. We currently do not use the 3-plane localizer or ZIP (zero-interpolation) options for knee imaging.

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At Stanford and at the Palo Alto VA Medical Center, we routinely use fast spin echo sequences to evaluate the knee menisci. Controversy has existed about the utility of proton density fast spin echo in the evaluation of tissues with short T2 relaxation times. In proton density fast spin echo imaging, T2 relaxation as the echo train approaches the edges of k-space results in a loss of image detail for short T2 species. Previously, some authors have shown a decreased sensitivity of fast spin echo for meniscal tears, which have relatively short T2 relaxation times. The current software, which limits inter-echo spacing, along with limiting the echo train lengths has allowed for efficient evaluation of meniscal tears without loss of accuracy.1 With the knee placed initially at isocenter, a localizer scan is not usually needed. The initial T1-weighted coronal images of the knee (Fig. 8.1) are useful for primary evaluation of the marrow signal, the medial collateral ligament, and lateral collateral ligament complex. In particular, the T1 weighting gives fluid low signal relative to fat, increasing the conspicuity of subchondral cyst formation. This series is also useful for evaluation of the cruciate ligaments and menisci. The use of the 512 matrix should not increase the scan time if the bandwidth is set correctly. Figure 8.1 (click on image to see enlarged view) Coronal T1-weighted image of a normal knee.

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¹ Cheung LP, Li KC, Hollett MD, Bergman AG, Herfkens RJ Meniscal tears of the knee: accuracy of detection with fast spin-echo MR imaging and arthroscopic correlation in 293 patients. Radiology 203(2): 508-12, 1997.