From Esaote S.p.A.; Esaote introduced the S-SCAN at RSNA in November 2007. The S-SCAN is a dedicated joint and spine MR scanner derived from the company's earlier G-SCAN system. Unlike the G-SCAN, neither the patient table nor the magnet can rotate from horizontal to vertical position. The patient table can only moved manually. Improved electronics, new coils for lumbar and cervical spine, new pulse sequences, a modified version of the magnet poles and gradient coils are used with a new software release in the S-SCAN.
Esaote North America is the exclusive U.S. distributor of this MRI device.

From GE Healthcare;
the Signa Infinity Magnetic Resonance system is a short bore, high performance, whole-body imaging system operating at 1.0 Tesla. The system can image in any orthogonal or oblique plane (including single and double axis oblique), using a wide variety of pulse sequences.

Magnetic resonance imaging (MRI) of the spine is a noninvasive procedure to evaluate different types of tissue, including the spinal cord, vertebral disks and spaces between the vertebrae through which the nerves travel, as well as distinguish healthy tissue from diseased tissue.
The cervical, thoracic and lumbar spine MRI should be scanned in individual sections. The scan protocol parameter like e.g. the field of view (FOV), slice thickness and matrix are usually different for cervical, thoracic and lumbar spine MRI, but the method is similar. The standard views in the basic spinal MRI scan to create detailed slices (cross sections) are sagittal T1 weighted and T2 weighted images over the whole body part, and transverse (e.g. multi angle oblique) over the region of interest with different pulse sequences according to the result of the sagittal slices. Additional views or different types of pulse sequences like fat suppression, fluid attenuation inversion recovery (FLAIR) or diffusion weighted imaging are created dependent on the indication.

Indications:

Contrast enhanced MRI techniques delineate infections vs. malignancies, show a syrinx cavity and support to differentiate the postoperative conditions. After surgery for disk disease, significant fibrosis can occur in the spine. This scarring can mimic residual disk herniation. Magnetic resonance myelography evaluates spinal stenosis and various intervertebral discs can be imaged with multi angle oblique techniques. Cine series can be used to show true range of motion studies of parts of the spine. Advanced open MRI devices are developed to perform positional scans in the position of pain or symptom (e.g. Uprightâ„¢ MRI formerly Stand-Up MRI).

(SARGE) Spoiled GRE sequences use a spoiler gradient on the slice select axis to destroy any remaining transverse magnetization after the readout gradient, with the result of short repetition times. This type of sequences use semi-random changes in the phase of RF pulses to produce a spatially independent phase shift.

See also Gradient Echo Sequence.

(SFP or SSFP) Steady state free precession is any field or gradient echo sequence in which a non-zero steady state develops for both components of magnetization (transverse and longitudinal) and also a condition where the TR is shorter than the T1 and T2 times of the tissue. If the RF pulses are close enough together, the MR signal will never completely decay, implying that the spins in the transverse plane never completely dephase. The flip angle and the TR maintain the steady state. The flip angle should be 60-90° if the TR is 100 ms, if the TR is less than 100 ms, then the flip angle for steady state should be 45-60°.
Steady state free precession is also a method of MR excitation in which strings of RF pulses are applied rapidly and repeatedly with interpulse intervals short compared to both T1 and T2. Alternating the phases of the RF pulses by 180° can be useful. The signal reforms as an echo immediately before each RF pulse; immediately after the RF pulse there is additional signal from the FID produced by the pulse.
The strength of the FID will depend on the time between pulses (TR), the tissue and the flip angle of the pulse; the strength of the echo will additionally depend on the T2 of the tissue. With the use of appropriate dephasing gradients, the signal can be observed as a frequency-encoded gradient echo either shortly before the RF pulse or after it; the signal immediately before the RF pulse will be more highly T2 weighted. The signal immediately after the RF pulse (in a rapid series of RF pulses) will depend on T2 as well as T1, unless measures are taken to destroy signal refocusing and prevent the development of steady state free precession.
To avoid setting up a state of SSFP when using rapidly repeated excitation RF pulses, it may be necessary to spoil the phase coherence between excitations, e.g. with varying phase shifts or timing of the exciting RF pulses or varying spoiler gradient pulses between the excitations.
Steady state free precession imaging methods are quite sensitive to the resonant frequency of the material. Fluctuating equilibrium MR (see also FIESTA and DRIVE)and linear combination SSFP actually use this sensitivity for fat suppression. Fat saturated SSFP (FS-SSFP) use a more complex fat suppression scheme than FEMR or LCSSFP, but has a 40% lower scan time.
A new family of steady state free precession sequences use a balanced gradient, a gradient waveform, which will act on any stationary spin on resonance between 2 consecutive RF pulses and return it to the same phase it had before the gradients were applied.
This sequences include, e.g. Balanced Fast Field Echo - bFFE, Balanced Turbo Field Echo - bTFE, Fast Imaging with Steady Precession - TrueFISP and Balanced SARGE - BASG.

See also FIESTA.