FLAIR imaging using nonselective inversion pulses combined with slice excitation order cycling and k-space reordering to reduce flow artifacts.

High-signal artifacts produced by cerebrospinal fluid (CSF) flow can adversely affect fluid-attenuated inversion recovery (FLAIR) imaging of the brain and spinal cord. This study explores the use of a nonslice-selective inversion pulse to eliminate CSF flow artifacts together with a technique called "K-space Reordered by Inversion-time for each Slice Position" (KRISP) to achieve constant contrast in a multislice acquisition. Theory shows that with this method the CSF point spread function (PSF) has a minimum at the center and attenuated side lobes, providing CSF suppression, but residual edge signals remain. The PSF for brain is only mildly attenuated and signals for extended regions are not attenuated. KRISP FLAIR sequences were assessed in 15 patients (10 brain and five spinal cord cases). The images showed reduced CSF and blood flow artifacts and higher conspicuity of the cortex, meninges, ventricular system, brainstem, and cerebellum when compared with conventional FLAIR sequences.     

Dyke award. Harmonic modulation of proton MR precessional phase by pulsatile motion: origin of spinal CSF flow phenomena

The effects of pulsatile motion on MR imaging of spinal CSF were quantitatively evaluated with a spine phantom that simulated spinal CSF pulsation. Two fundamental interdependent pulsation flow phenomena were observed: variable reductions in signal intensity of pulsatile CSF (signal loss) and spatial mismapping of this signal beyond the confines of the subarachnoid space (phase-shift images). Phase-shift images were observed as multiple regions of signal intensity conforming morphologically to the subarachnoid space but displaced symmetrically from it along the phase-encoding axis, either added to or subtracted from stationary signal intensity. Both CSF pulsation flow phenomena occurred secondary to harmonic modulation of proton precessional phase (temporal phase shift) by the unique pulsatile motion of spinal CSF when the repetition time was not an integral multiple of the pulsation period. Each flow phenomenon was analyzed with the spine phantom independently to control individual imaging and physiologic parameters including imaging plane, repetition time, echo time, slice thickness, number of echoes, number of excitations, CSF pulsation amplitude, and CSF pulsation period. In the axial plane, signal loss was present on both first- and second-echo images and was more pronounced with larger pulsation amplitudes and smaller slice thicknesses. A quantitative relationship between these two parameters allowed the prediction of CSF pulsation amplitude when the slice thickness was known and the CSF signal intensity was measured. In the sagittal plane, signal loss was present on first-echo images, was more pronounced with larger pulsation amplitudes, and underwent incomplete even-echo rephasing on second-echo images. Phase-shift images were influenced by the relationship between repetition time and CSF pulsation period. They were partly eliminated on sagittal but not on axial second-echo images because of incomplete even-echo rephasing. Both signal loss and phase-shift images were completely eliminated with CSF gating or pseudogating, indicating the rationale for gating during clinical spinal MR. The clinical significance of these findings is that awareness of the existence of spinal CSF pulsation flow phenomena avoids diagnostic confusion, whereas understanding their etiology provides a rational approach, such as CSF gating, to eliminate them.     

Cerebrospinal fluid flow in the cervical spinal canal in patients with chronic neck pain

Purpose: To measure the cerebrospinal fluid (CSF) velocity in the cervical spinal canal both above and below a stenotic segment in patients with cervical spinal stenosis. The cord velocity was also measured at the level of C2.Material and Methods: Thirteen patients with chronic neck pain were examined with MR imaging. The degree of cervical spinal stenosis was assessed and measured on MR images and CSF velocity in the cervical spinal canal was measured using the phase MR flow quantification method at the level of C2 and below the stenotic segment. The cord motion was measured at the level of C2.Results: The peak velocities of CSF in front of the cord at the level of C2 were, on average, a little higher than behind the cord, but the interindividual variation was high. The caudal or rostral velocities of CSF above and below the stenotic segment could be measured in most cases and they were not dependent on the degree of stenosis when assessed visually. When the stenosis was assessed by relating the cord area to the dural sac area, a statistical correlation between narrow spinal canal and high velocities in the anterior CSF space below the stenotic segment was found.Conclusion: Spinal stenosis does not alter the cord or CSF velocities at the C2 level, but increases the velocity of CSF in the anterior CSF space below the stenotic segment when the stenosis is assessed by cord and dural sac area measurements.     

Cervical spine: MR imaging with a partial flip angle, gradient- refocused pulse sequence. Part II. Spinal cord disease

A magnetic resonance imaging pulse sequence (GRASS) with a short repetition time (TR), short echo time (TE), partial flip angle, and gradient refocused echo was prospectively evaluated for the detection of cervical cord disease that caused minimal or no cord enlargement in eight patients. Sagittal T2-weighted, cerebrospinal fluid (CSF)-gated images and sagittal and axial GRASS images were obtained in all patients. The following GRASS parameters were manipulated to determine their effect on signal-to-noise ratio (S/N) and contrast: flip angle (4 degrees-18 degrees), TR (22-50 msec), and TE (12.5-25 msec). Flip angle had the greatest effect on S/N and contrast. There were no differences between axial and sagittal imaging for the spinal cord or lesion. However, because the signal intensity of CSF did differ on sagittal and axial images and because this influenced the conspicuity of lesions, there was a difference in the useful flip angle range for axial and sagittal imaging. No one set of imaging parameters was clearly superior, and in all patients, the gated image was superior to the sagittal GRASS image in lesion detection. GRASS images should be used in the axial plane primarily to confirm spinal cord disease detected on sagittal CSF-gated images. For this, a balanced approach is suggested (TR = 40 msec, TE = 20 msec, with flip angles of 4 degrees-6 degrees for sagittal and 6 degrees-8 degrees for axial imaging).     

Human brain motion and cerebrospinal fluid circulation demonstrated with MR velocity imaging

Present theory holds that pulsatile pressure of cerebrospinal fluid (CSF) is driven by the force of expansion of the choroid plexus. Alternate theories postulating that a possible movement of the brain is involved in pumping CSF have not, to the authors' knowledge, been substantiated heretofore. In this study, in vivo, quantitative magnetic resonance (MR) imaging methods were developed to show reproducible magnitudes and directions of CSF flow. Measurements were obtained with a new MR velocity imaging technique at high resolution (0.4 mm/sec), requiring 64 cardiac cycles per image. Twenty-five healthy volunteers and five patients were studied. Observations of pulsatile brain motion, ejection of CSF out of the cerebral ventricles, and simultaneous reversal of CSF flow direction in the basal cisterns toward the spinal canal, taken together, suggest that a vascular-driven movement of the entire brain may be directly pumping the CSF circulation. The authors describe what they believe to be the first observations and measurements of human brain motion, which occurs in extensive internal regions (particularly the diencephalon and brain stem) and is synchronous with cardiac systole.     

Low flip angle gradient echo magnetic resonance imaging of the cervical spine at 0.3 tesla

The influence of flip angle and TR on signal to noise ratio and contrast between cerebrospinal fluid (CSF) and cord was evaluated in cervical spine imaging in 5 volunteers, using gradient echo technique. All experiments were performed on a 0.3 tesla Fonar beta-3000 M scanner using solenoidal surface coils. The most useful sequence was considered to be TR/TE = 300/12 ms and 10 degrees flip angle. This sequence provided images with a 'myelographic appearance' with good delineation of cord, CSF and epidural space. The grey and white matter was also regularly visualized. The acquisition time was considerably shorter than would have been necessary if a long TR/TE spin echo sequence had been used to obtain the same contrast pattern and the sequence was not as sensitive to motion as was the spin echo sequence. The sequence was also evaluated in 10 patients with degenerative disease and in 5 with lesions in the cord. The gradient echo sequence was found to be equal to or better than short and long TR/TE spin echo sequences in demonstrating narrowing of the spinal canal and cord lesion. The drawback is the limited signal to noise ratio.     

MR cisternography and myelography with Gd-DTPA in monkeys

To enhance the contrast between cerebrospinal fluid (CSF), brain, spinal cord, and surrounding meninges and bone on magnetic resonance (MR) images, as well as to study CSF flow, gadolinium-DTPA was injected in the subarachnoid space of eight monkeys. Six doses of progressively higher concentrations (from .125 mmol to 250 mmol) were injected every 30-40 minutes. Images of head and spine were obtained at .26 T or .5 T in sagittal and axial planes, using both spin-echo and inversion-recovery sequences in 13 imaging experiments. Marked, consistent changes of signal intensity in the CSF cavities were observed following the injections. These changes were dose related and occurred at different times in the areas close to the injection site versus those distant, a disparity that obviously was related to CSF flow. Gd-DTPA cisternography and myelography may be valuable in MR imaging of central nervous system disease, such as tumors adjacent to the CSF cavities, abnormal CSF collections (e.g., arachnoidal cysts), CSF rhinorrhea and otorrhea, syringohydromyelia, and studies of hydrocephalus and CSF flow dynamics.     

Functional magnetic resonance imaging of the human lumbar spinal cord

PURPOSE: To determine whether consistent regions of activity could be observed in the lumbar spinal cord of single subjects with spin-echo functional MRI (fMRI) if several repeated experiments were performed within a single imaging session. MATERIALS AND METHODS: Repeated fMRI experiments of the human lumbar spinal cord were performed at 1.5 T with a single-shot spin-echo technique (half-Fourier single-shot turbo spin-echo (HASTE)) as used by previous investigators, and a modified method (fluid-attenuated inversion recovery (FLAIR)-HASTE) that nulled the otherwise highly variable signal from the cerebrospinal fluid (CSF). RESULTS: FLAIR-HASTE reduced the variability of the signal in the CSF region to background levels, and presumably reduced associated artifacts in the spinal cord. Consistent areas of activation in the spinal cord in response to a thermal stimulus just below the knee were not observed across the fMRI experiments with either method. CONCLUSION: FLAIR-HASTE was useful for removing artifact in the spinal cord signal induced by variability in the CSF signal. However, with the techniques used in this study, we were not able to confirm the presence of a consistent fMRI response in the lumbar spinal cord because of the signal enhancement by extravascular protons (SEEP) effect during thermal stimulation of the hindlimb.     

Dynamic visualization of arachnoid adhesions in a patient with idiopathic syringomyelia using high‐resolution cine magnetic resonance imaging at 3T

A 39‐year‐old female patient with thoracic syringomyelia underwent routine magnetic resonance imaging (MRI) and 3 T MRI to investigate the value of retrospectively cardiac‐gated cine steady‐state free precession (SSFP) MRI in the preoperative and postoperative diagnosis of arachnoid membranes in the spinal subarachnoid space. Therefore, 3T MRI included sagittal and transverse retrospectively cardiac‐gated cine balanced fast‐field echo (balanced‐FFE) sequences both preoperatively and after microsurgical lysis of arachnoid adhesions and expansive duraplasty. Arachnoid membranes were detected and this result was correlated with intraoperative findings and the results of routine cardiac‐gated phase‐contrast cerebrospinal fluid (CSF) flow MRI. Retrospectively cardiac‐gated cine SSFP MRI enabled imaging of arachnoid membranes with high spatial resolution and sufficient contrast to delineate them from hyperintense CSF preoperatively and postoperatively. The images were largely unaffected by artifacts. Surgery confirmed the presence of arachnoid adhesions in the upper thoracic spine. Not all arachnoid membranes that were seen on cine balanced‐FFE sequences caused significant spinal CSF flow blockages in cardiac‐gated phase‐contrast CSF flow studies. In conclusion, retrospectively cardiac‐gated cine SSFP MRI may become a valuable tool for the preoperative detection of arachnoid adhesions and the postoperative evaluation of microsurgical adhesiolysis in patients with idiopathic syringomyelia. J. Magn. Reson. Imaging 2010. © 2010 Wiley‐Liss, Inc.     

Idiopathic spinal cord herniation: value of MR phase-contrast imaging.

We report two patients with an idiopathic transdural spinal cord herniation at the thoracic level. Phase-contrast MR imaging was helpful in showing an absence of CSF flow ventral to the herniated cord and a normal CSF flow pattern dorsal to the cord, which excluded a compressive posterior arachnoid cyst.     

CSF-gated MR imaging of the spine: theory and clinical implementation

A spine phantom and cervical spines of seven volunteers were studied with cerebrospinal fluid (CSF)-gated magnetic resonance imaging to optimize acquisition factors reducing CSF flow artifacts. Peripheral gating was performed with either an infrared reflectance photoplethysmograph or peripheral arterial Doppler signal. The effects of effective repetition time, echo train, trigger delay, number of sections, and imaging plane on image quality were evaluated. Gated imaging of oscillatory CSF motion simulated constant-velocity flow and reduced CSF flow artifacts caused by cardiac-dependent temporal phase-shift effects. Velocity compensation on sagittal even-echo images with a symmetric short-echo time echo train reduced the remaining CSF flow artifacts caused by spatial phase-shift effects. Overall gated imaging time was not increased compared with nongated imaging and was reduced when improved image quality permitted the use of fewer excitations. These results suggest that the combination of CSF gating and flow compensation is clinically useful and efficient because it improves image quality without prolonging imaging time.     

Pulsatile brain movement and associated hydrodynamics studied by magnetic resonance phase imaging

Summary Brain tissue movements were studied in axial, sagittal and coronal planes in 15 healthy volunteers, using a gated spin echo MRI sequence. All movements had characteristics different from those of perfusion and diffusion. The highest velocities occurred during systole in the basal ganglia (maximum 1.0 mm/s) and brain stem (maximum 1.5 mm/s). The movements were directed caudally, medially and posteriorly in the basal ganglia, and caudally-anteriorly in the pons. Caudad and anterior motion increased towards the foramen magnum and towards the midline. The resultant movement occurred in a funnelshaped fashion as if the brain were pulled by the spinal cord. This may be explained by venting of brain and cerebrospinal fluid (CSF) through the tentorial notch and foramen magnum. The intracranial volume is assumed to be always constant by the Monro-Kellie doctrine. The intracranial dynamics can be viewed as an interplay between the spatial requirements of four main components: arterial blood, capillary blood (brain volume), venous blood and CSF. These components could be characterized, and the expansion of the arteries and the brain differentiated, by applying the Monro-Kellie doctrine to every moment of the cardiac cycle. The arterial expansion causes a remoulding of the brain that enables its piston-like action. The arterial expansion creates the prerequisites for the expansion of the brain by venting CSF to the spinal canal. The expansion of the brain is, in turn, responsible for compression of the ventricular system and hence for the intraventricular flow of CSF.     

Quantitative measurement of intervertebral disc signal using MRI

AIM: To investigate the spinal cord as an alternative intra-body reference to cerebrospinal fluid (CSF) in evaluating thoracic disc signal intensity. MATERIALS AND METHODS: T2-weighted magnetic resonance imaging (MRI) images of T6-T12 were obtained using 1.5 T machines for a population-based sample of 523 men aged 35-70 years. Quantitative data on the signal intensities were acquired using an image analysis program (SpEx). A random sample of 30 subjects and intraclass correlation coefficients (ICC) were used to examine the repeatability of the spinal cord measurements. The validity of using the spinal cord as a reference was examined by correlating cord and CSF samples. Finally, thoracic disc signal was validated by correlating it with age without adjustment and adjusting for either cord or CSF. Pearson's r was used for correlational analyses. RESULTS: The repeatability of the spinal cord signal measurements was extremely high (>or=0.99). The correlations between the signals of spinal cord and CSF by level were all above 0.9. The spinal cord-adjusted disc signal and age correlated similarly with CSF-adjusted disc signal and age (r=-0.30 to -0.40 versus r=-0.26 to -0.36). CONCLUSION: Adjacent spinal cord is a good alternative reference to the current reference standard, CSF, for quantitative measurements of disc signal intensity. Clearly fewer levels were excluded when using spinal cord as compared to CSF due to missing reference samples.     

Focal Anterior Displacement of the Thoracic Spinal Cord without Evidence of Spinal Cord Herniation or an Intradural Mass

Objective

We report magnetic resonance imaging (MRI) findings on focal anterior displacement of the thoracic spinal cord in asymptomatic patients without a spinal cord herniation or intradural mass.

Materials and Methods

We identified 12 patients (male:female = 6:6; mean age, 51.7; range, 15-83 years) between 2007 and 2011, with focal anterior displacement of the spinal cord and without evidence of an intradural mass or spinal cord herniation. Two radiologists retrospectively reviewed the MRI findings in consensus.

Results

An asymmetric spinal cord deformity with a focal dented appearance was seen on the posterior surface of the spinal cord in all patients, and it involved a length of 1 or 2 vertebral segments in the upper thoracic spine (thoracic vertebrae 1-6). Moreover, a focal widening of the posterior subarachnoid space was also observed in all cases. None of the patients had myelopathy symptoms, and they showed no focal T2-hyperintensity in the spinal cord with the exception of one patient. In addition, cerebrospinal fluid (CSF) flow artifacts were seen in the posterior subarachnoid space of the affected spinal cord level. Computed tomography myelography revealed preserved CSF flow in the two available patients.

Conclusion

Focal anterior spinal cord indentation can be found in the upper thoracic level of asymptomatic patients without a spinal cord herniation or intradural mass.     

DWI of the spinal cord with reduced FOV single‐shot EPI

Single‐shot echo‐planar imaging (ss‐EPI) has not been used widely for diffusion‐weighted imaging (DWI) of the spinal cord, because of the magnetic field inhomogeneities around the spine, the small cross‐sectional size of the spinal cord, and the increased motion in that area due to breathing, swallowing, and cerebrospinal fluid (CSF) pulsation. These result in artifacts with the usually long readout duration of the ss‐EPI method. Reduced field‐of‐view (FOV) methods decrease the required readout duration for ss‐EPI, thereby enabling its practical application to imaging of the spine. In this work, a reduced FOV single‐shot diffusion‐weighted echo‐planar imaging (ss‐DWEPI) method is proposed, in which a 2D spatially selective echo‐planar RF excitation pulse and a 180° refocusing pulse reduce the FOV in the phase‐encode (PE) direction, while suppressing the signal from fat simultaneously. With this method, multi slice images with higher in‐plane resolutions (0.94 × 0.94 mm² for sagittal and 0.62 × 0.62 mm² for axial images) are achieved at 1.5 T, without the need for a longer readout. Magn Reson Med 60:468–473, 2008. © 2008 Wiley‐Liss, Inc.     

椎管内肠源性囊肿的磁共振影像诊断

目的：研究椎管内肠源性囊肿的磁共振影像学特征．材料和方法：收集了19例经手术和病理证实的椎管内肠源性囊肿的资料。分析其磁共振影像表现。结果：19例椎管内肠源性囊肿中．位于硬膜下18例，位于硬膜外1例．病变量常见部位是胸段椎管内(47%)，其次为颈段(37%)和颅椎结合部(16%)；18例(95%)囊肿位于中线部位脊髓腹侧面10例肠源性囊肿患者同时伴有脊柱的其它畸形．19例肠源性囊肿的磁共振影像表现包括：T1加权像上为脑脊液信号强度影5例，稍高于脑脊液信号强度影13例．与脊髓信号强度近似者1例；T1加权像时，7例囊肿信号强度等于脑脊液信号强度。2例稍高于脑脊液信号强度．所有囊肿的壁均光滑．囊内信号均匀．15例在磁共振横断面图像上见囊肿部分或大部分被镶嵌在脊髓中。结论：磁共振影像可以清楚地显示肠源性囊肿的全貌，当在脊髓腹侧面中线部位硬膜下腔发现一边缘光滑的囊肿．其Tl和T1加权像上信号强度等于或高于脑脊液并伴有其它脊柱畸形时。应高度提示肠源性囊肿的诊断．     

MR measurement of spinal CSF flow with the RACE technique.

The purpose of our study was the application and validation of a phase-sensitive pulse sequence that allowed real time CSF flow measurement without need for electrocardiographic (ECG) synchronization. After excitation of a slice perpendicular to the axis of the spine, projective data were obtained with a gradient echo sequence [contrast enhanced Fourier acquired steady-state technique (CE-FAST)] without spin warp gradient [real time acquisition and evaluation of motion technique (RACE)], allowing one-dimensional spatial resolution across the region of interest with a total sampling time of 20-30 ms. The sequence was calibrated with a spinal CSF phantom with oscillatory fluid motion. The calculated mean pulsation amplitudes of 20 healthy volunteers in the cervical region were 16 mm (range 9-36 mm), in the thoracic region 11 mm (5-21 mm), and in the lumbar region 3 mm (1-6 mm). The technique was capable of demonstrating physiologic alterations of CSF flow during respiratory maneuvers and may provide a tool to evaluate the altered CSF dynamics resulting from spinal block, inflammatory processes, or hemorrhage.     

Automated Quantitation of Spinal CSF Volume and Measurement of Craniospinal CSF Redistribution following Lumbar Withdrawal in Idiopathic Intracranial Hypertension

BACKGROUND AND PURPOSE:Automated methods for quantitation of tissue and CSF volumes by MR imaging are available for the cranial but not the spinal compartment. We developed an iterative method for delineation of the spinal CSF spaces for automated measurements of CSF and cord volumes and applied it to study craniospinal CSF redistribution following lumbar withdrawal in patients with idiopathic intracranial hypertension.MATERIALS AND METHODS:MR imaging data were obtained from 2 healthy subjects and 8 patients with idiopathic intracranial hypertension who were scanned before, immediately after, and 2 weeks after diagnostic lumbar puncture. Imaging included T1-weighted and T2-weighted sequences of the brain and T2-weighted scans of the spine. Repeat scans in 4 subjects were used to assess measurement reproducibility. Whole CNS CSF volumes measured prior to and following lumbar puncture were compared with the withdrawn amounts of CSF.RESULTS:CSF and cord volume measurements were highly reproducible with mean variabilities of −0.7% ± 1.4% and −0.7% ± 1.0%, respectively. Mean spinal CSF volume was 77.5 ± 8.4 mL. The imaging-based pre- to post-CSF volume differences were consistently smaller and strongly correlated with the amounts removed (R = 0.86, P = .006), primarily from the lumbosacral region. These differences are explained by net CSF formation of 0.41 ± 0.18 mL/min between withdrawal and imaging.CONCLUSIONS:Automated measurements of the craniospinal CSF redistribution following lumbar withdrawal in idiopathic intracranial hypertension reveal that the drop in intracranial pressure following lumbar puncture is primarily related to the increase in spinal compliance and not cranial compliance due to the reduced spinal CSF volume and the nearly unchanged cranial CSF volume.

The total amount of CSF and its craniospinal distribution are important for understanding of CSF-related brain and spinal cord disorders and CSF physiology in general. Changes in CSF circulation or distribution between the cranium and spinal canal or both have been observed in several neurologic disorders, including Alzheimer disease,¹ idiopathic normal pressure hydrocephalus,² idiopathic intracranial hypertension (IIH),³ and even during pregnancy.⁴ A change in body posture also affects the craniospinal CSF distribution, with a shift from the cranium to the spinal canal contributing to the lower intracranial pressure observed in the upright-versus-supine postures.⁵ CSF volume in the spinal canal is also influenced by abdominal compression and hyperventilation.⁶ In addition, the amount of CSF in the thecal sac has been shown to influence the effectiveness of spinal anesthesia.⁷ Not only the spinal CSF volume but also the spinal cord volume is of clinical relevance, especially for cord atrophy progression such as in multiple sclerosis.⁸MR imaging–based automated methods of quantitation of brain tissues and intracranial CSF volumes^9,10 have considerably advanced the quantitative-based diagnostic capability of many neurologic problems, yet comparable methods for the spinal cord and the spinal CSF volumes are not widely available. Measurement of the spinal CSF volume in MR imaging is challenging because of the overall smaller volumes compared with the brain and cranial volumes and due to the length of the spinal canal, which necessitates the use of multiple overlapping acquisitions with potentially varying image nonuniformity.Previous studies on dose response in epidural anesthesia focused on measurements of the CSF volumes in the low thoracic and lumbosacral regions.^4,6,11 The CSF volume in the whole spinal canal was reported only in a small number of studies that were constrained by limited image resolution and manual delineation of the CSF space.^11,12 A recent advancement toward automated spinal CSF volume measurements is the development of a method that uses thresholding and voxel connectivity.¹³ Recent effort in the assessment of spinal cord atrophy in multiple sclerosis includes semiautomated approaches for the measurement of the cord cross-sectional areas in both cervical and thoracic regions.¹⁴This article describes an iterative method of delineating the CSF spaces and the spinal cord throughout the spinal canal. Measurement reproducibility was assessed from repeat measurements in the same subjects. The method efficacy is demonstrated by its application to studying the impact of CSF withdrawal by lumbar puncture (LP) on the craniospinal CSF redistribution in IIH. Only limited information on CSF redistribution following withdrawal is available, even though this is a commonly used diagnostic procedure in CSF-related disorders.     

In vivo magnetic resonance imaging of the human cervical spinal cord at 3 Tesla

PURPOSE: To demonstrate the feasibility of obtaining high-quality magnetic resonance (MR) images of the human cervical spinal cord in vivo at a magnetic field strength of 3 T and to optimize the signal contrast between gray matter, white matter, and cerebrospinal fluid (CSF) on 2D gradient recalled echo (GRE) images of the cervical spinal cord. MATERIALS AND METHODS: Using a custom-built, anatomically molded radio frequency (RF) surface coil, the repetition time and flip angle of a 2D GRE sequence were systematically varied in five volunteers to assess tissue contrast in the cervical spinal cord. RESULTS: The 2D GRE parameters for an optimal balance between gray-white matter and CSF-white matter contrast at 3 T were determined to be a time-to-repetition (TR) of 2000 msec and a flip angle of 45 degrees, with the constant short time-to-echo (TE) of 12 msec used in this study. Excellent tissue contrast and visualization of the internal anatomy of the spinal cord was demonstrated reproducibly in eight subjects using these optimal parameters. CONCLUSION: This study demonstrates that imaging the cervical spinal cord and delineating internal spinal cord structures such as gray and white matter is feasible at 3 T.