Diffusion-weighted Magnetic Resonance Neurography Research Articles

Phase angle of bioelectrical impedance analysis as an indicator for diabetic polyneuropathy in type 2 diabetes mellitus.

Due to the heterogenous clinical symptoms and deficits, the diagnosis of diabetic polyneuropathy (DPN) is still difficult in clinical routine leading to increased morbidity and mortality. We studied the correlation of phase angle (PhA) of bioelectrical impedance analysis (BIA) with clinical, laboratory and physical markers of DPN to evaluate PhA as possible diagnostic method for DPN. In this cross-sectional observational study as part of the Heidelberg Study on Diabetes and Complications we examined 104 healthy individuals and 205 patients with type 2 diabetes mellitus (T2D), amongst which 63 had DPN. The PhA was calculated from multi-frequency BIA. Nerve conduction studies (NCS), quantitative sensory testing (QST) and diffusion-weighted magnetic resonance neurography (MRN) to determine fractional anisotropy (FA) reflecting peripheral nerve integrity were performed. T2D patients with DPN had lower PhA values (5.71 ± 0.10) compared to T2D patients without DPN (6.07 ± 0.08, p = 0.007,  + 6.1%) and healthy controls (6.18 ± 0.08, p < 0.001,  + 7.9%). Confounder-adjusted analyses showed correlations of the PhA with conduction velocities and amplitudes of the peroneal (β=0.28; β=0.31, p < 0.001) and tibial nerves (β=0.28; β=0.32, p < 0.001), Z-scores of QST (thermal detection β=0.30, p < 0.05) and the FA (β=0.60, p < 0.001). ROC analysis showed similar performance of PhA in comparison to mentioned diagnostic methods. The study shows that PhA is in comparison to other test systems used, at least an equally good and much easier to handle, investigator independent marker for detection of DPN.

Sciatic nerve fractional anisotropy and neurofilament light chain protein are related to sensorimotor deficit of the upper and lower limbs in patients with type 2 diabetes.

Diabetic sensorimotor polyneuropathy (DSPN) is one of the most prevalent and poorly understood diabetic microvascular complications. Recent studies have found that fractional anisotropy (FA), a marker for microstructural nerve integrity, is a sensitive parameter for the structural and functional nerve damage in DSPN. The aim of this study was to investigate the significance of proximal sciatic nerve's FA on different distal nerve fiber deficits of the upper and lower limbs and its correlation with the neuroaxonal biomarker, neurofilament light chain protein (NfL). Sixty-nine patients with type 2 diabetes (T2DM) and 30 healthy controls underwent detailed clinical and electrophysiological assessments, complete quantitative sensory testing (QST), and diffusion-weighted magnetic resonance neurography of the sciatic nerve. NfL was measured in the serum of healthy controls and patients with T2DM. Multivariate models were used to adjust for confounders of microvascular damage. Patients with DSPN showed a 17% lower sciatic microstructural integrity compared to healthy controls (p<0.001). FA correlated with tibial and peroneal motor nerve conduction velocity (NCV) (r=0.6; p<0.001 and r=0.6; p<0.001) and sural sensory NCV (r=0.50; p<0.001). Participants with reduced sciatic nerve´s FA showed a loss of function of mechanical and thermal sensation of upper (r=0.3; p<0.01 and r=0.3; p<0.01) and lower (r=0.5; p<0.001 and r=0.3; p=<0.01) limbs and reduced functional performance of upper limbs (Purdue Pegboard Test for dominant hand; r=0.4; p<0.001). Increased levels of NfL and urinary albumin-creatinine ratio (ACR) were associated with loss of sciatic nerve´s FA (r=-0.5; p<0.001 and r= -0.3, p= 0.001). Of note, there was no correlation between sciatic FA and neuropathic symptoms or pain. This is the first study showing that microstructural nerve integrity is associated with damage of different nerve fiber types and a neuroaxonal biomarker in DSPN. Furthermore, these findings show that proximal nerve damage is related to distal nerve function even before clinical symptoms occur. The microstructure of the proximal sciatic nerve and is also associated with functional nerve fiber deficits of the upper and lower limbs, suggesting that diabetic neuropathy involves structural changes of peripheral nerves of upper limbs too.

Magnetic Resonance Neurography Reveals Smoking-Associated Decrease in Sciatic Nerve Structural Integrity in Type 2 Diabetes.

ObjectiveIt is controversially discussed in how far smoking contributes to diabetic polyneuropathy (DPN) in type 2 diabetes (T2D). Diffusion-weighted magnetic resonance neurography (MRN) at 3 Tesla has been shown to provide objective values for structural nerve integrity in patients with T2D. The aim of this study was to investigate the contribution of cigarette smoking on structural nerve integrity in T2D.MethodsThis cross-sectional prospective cohort study investigated the structural integrity of the sciatic nerve in 10 smokers, 40 never-smokers, and 20 ex-smokers with T2D and 10 healthy control subjects, using diffusion tensor imaging MRN at 3 Tesla and semi-automated nerve fiber tracking. Results were correlated with clinical, electrophysiological, and serological data.ResultsThe sciatic nerve’s fractional anisotropy (FA), a parameter for structural nerve integrity, was significantly lower in smokers with T2D when compared to controls (p = 0.002) and never-smokers (p = 0.015), and lower in ex-smokers when compared to controls (p = 0.015). In addition, sciatic nerve radial diffusivity, a marker of myelin damage, was increased in smokers versus controls and never-smokers (p = 0.048, p = 0.049, respectively). Furthermore, FA in T2D patients was negatively correlated with clinical and electrophysiological markers of DPN. FA also showed negative correlations with the pulse wave velocity, a marker of arterial stiffness and associated microangiopathy, in controls (r = −0.70; p = 0.037), never-smokers (r = −0.45; p = 0.004), ex-smokers (r = −0.55; p = 0.009), and a similar trend in smokers (r = −0.63; p = 0.076). Negative correlations were found between FA and skin auto-fluorescence, a marker of tissue advanced glycation end product accumulation and therefore long-term glycemic stress in T2D, in never-smokers (r = −0.39; p = 0.020) and smokers (r = −0.84; p = 0.004), but not in ex-smokers (r = −0.07; p = 0.765).ConclusionThe findings indicate that smoking contributes to sciatic nerve damage in T2D, potentially worsening DPN due to glycemic stress and less microangiopathy-associated myelin damage in active smokers, while angiopathic effects predominate in ex-smokers. To stop smoking may therefore pose a promising preventive measure to slow the progression of DPN in T2D.

Diagnostic performance of diffusion-weighted MR neurography as an adjunct to conventional MRI for the assessment of brachial plexus pathology.

To investigate the diagnostic performance of diffusion-weighted (DW) MR neurography as an adjunct to conventional MRI for the assessment of brachial plexus pathology. DW MR neurography scans (short tau inversion recovery fat suppression and b-value of 800s/mm2) of 15 consecutive patients with and 45 randomly selected patients without brachial plexus abnormalities were independently and blindly reviewed by a 5th year radiology resident, a junior neuroradiologist, and a senior neuroradiologist. Median interpretation times ranged between 20 and 30s. Interobserver agreement was substantial (κ coefficients of 0.715-0.739). For the 5th year radiology resident, sensitivity was 53.3% (95% CI, 30.1-75.2%) and specificity was 100% (95% CI, 92.1-100%). For the junior neuroradiologist, sensitivity was 66.7% (95% CI, 41.7-84.8%) and specificity was 100% (95% CI, 92.1-100%). For the senior neuroradiologist, sensitivity was 73.3% (95% CI, 48.1-89.1%) and specificity was 95.6% (95% CI, 85.2-98.8%). Traumatic injury, metastases, radiation-induced plexopathy, schwannoma, and inflammatory process of unknown cause could be detected by the majority of readers (100% detection rate for each disease entity by at least two readers). Neuralgic amyotrophy, iatrogenic injury after first rib resection, and cervical disc herniation causing root compression were not detected by the majority of readers (0% detection rate for each disease entity by at least two readers). DW MR neurography may be a useful adjunct when assessing for brachial plexus abnormalities, because interpretation time is relatively short and the majority of abnormalities can be detected. • DW MR neurography interpretation time of the brachial plexus is relatively short (median interpretation times of 20 to 30s). • Interobserver agreement between three readers with different levels of experience is substantial (κ coefficients of 0.715 to 0.739). • DW MR neurography can detect brachial plexus abnormalities with moderate sensitivity (53.3 to 73.3%) and high specificity (95.6 to 100%).

Hourglass-Like Constriction Neuropathy of the Upper Limb Nerve: Diffusion-Weighted Magnetic Resonance Neurography Imaging Findings.

The purposes of this study were to determine reliable diffusion-weighted magnetic resonance neurography (DW-MRN) features of hourglass-like constriction of the upper limb nerve and to evaluate the application value of DW-MRN compared with ultrasonography (US). We retrospectively reviewed MRN studies of 13 patients. Qualitative and quantitative image analyses were carried out. The number of constrictions based on DW-MRN and US findings was compared. Of the 13 cases, there were 7 cases with radial nerve abnormalities, 4 with median nerve abnormalities, and 2 with radial and median nerve abnormalities. Diffusion-weighted MRN showed a single-segmental constriction in 7 of 13 cases and multisegmental constrictions in 6 of 13 cases; the hourglass-like constriction appeared in all cases (13 of 13). Thirty-three nerve constrictions were found in DW-MRN, and 29 nerve constrictions were found in US. Diffusion-weighted MRN is a noninvasive and helpful diagnostic for hourglass-like constriction of the upper limb nerve.

Identifying lumbosacral plexus nerve root abnormalities in patients with sciatica using 3T readout-segmented echo-planar diffusion weighted MR neurography

ObjectivesTo investigate the accuracy of Diffusion Weighted Imaging (DWI) using the Readout Segmentation of Long Variable Echo-trains (RESOLVE) sequence in detecting lumbosacral nerve abnormalities.MethodsFollowing institutional ethics committee approval, patients with sciatica-type lower limb radicular symptoms (n = 110) were recruited and prospectively scanned using 3T MRI. Additional participants (n = 17) who underwent neurophysiological testing (EMG/NCV), were also prospectively studied. In addition to routine lumbar spine MRI, a DWI-RESOLVE sequence of the lumbosacral plexus was performed. Two radiologists, blinded to the side of patient symptoms, independently evaluated the MR images. The size and signal intensity changes of the nerves were evaluated using ordinal 4-point Likert-scales. Signal-to-noise ratio (SNR), apparent diffusion coefficient (ADC) and size were measured for affected and normal nerves. Inter-observer agreement was determined with kappa statistics; κ.ResultsIn patients who did not undergo EMG/NCV testing (n = 110), the DWI-RESOLVE sequence detected lumbosacral nerve abnormalities that correlated with symptoms in 36.3% (40/110). This is a similar percentage to patients who underwent EMG/NCV testing, which was positive and correlated with symptoms in 41.2% (7/17). Inter-observer agreement for evaluation of lumbosacral nerve abnormalities was excellent and ranged from 0.87 to 0.94. SNR and nerve size measurements demonstrated statistically significant differences for the L5 and S1 nerves (p value < 0.05) for patients who did not undergo EMG/NCV testing.ConclusionThe DWI-RESOLVE sequence is a promising new method that may permit accurate detection and localization of lumbar nerve abnormalities in patients with sciatica.

Identification of abnormalities in the lumbar nerve tract using diffusion-weighted magnetic resonance neurography.

Abnormalities of the lumbar nerve tract caused by congenital variations or high nerve root take-off angles are difficult to visualize. Diffusion-weighted magnetic resonance neurography (DW-MRN) has recently been introduced for imaging of the lumbosacral region. The aims of this study were to identify lumbar nerve tract abnormalities caused by congenital variation or a high nerve root take-off angle using DW-MRN and to assess the diagnostic value of this imaging modality. A total of 573 magnetic resonance images from 575 patients (261 men, 314 women; mean age 58.5years) with low back/leg pain were retrospectively analyzed. We classified congenital variations in the lumbar nerve roots using the Neidre and MacNab criteria and investigated nerve roots with a take-off angle of 60° or more. Congenital variations were identified in 8 patients (9 nerve roots, 1.6%). The most commonly identified variation was in the sacral nerve root (n = 5) followed by the L4 (n = 3) and L5 (n = 1) nerve roots. All variations identified were on the left side. There were 3 cases of type 1a variation, 1 of type 1b, 1 of type 2, and 4 of type 3. In total, 210 (36.6%) of the magnetic resonance images showed high nerve root take-off angles at the intervertebral foramen that was caused by disk herniation, spondylolisthesis, or osteophytes with degeneration. Patients with high nerve root take-off angles were significantly older than those without (P < 0.05). These slides can be retrieved under Electronic Supplementary Material.

Recent advances in magnetic resonance neuroimaging of lumbar nerve to clinical applications: A review of clinical studies utilizing Diffusion Tensor Imaging and Diffusion-weighted magnetic resonance neurography.

Much progress has been made in neuroimaging with Magnetic Resonance neurography and Diffusion Tensor Imaging (DTI) owing to higher magnetic fields and improvements in pulse sequence technology. Reports on lumbar nerve DTI have also increased considerably. Many studies have shown that the use of DTI in lumbar nerve lesions, such as lumbar foraminal stenosis and lumbar disc herniation, makes it possible to capture images of interruptions of tractography at stenotic sties, enabling the diagnosis of stenosis. DTI can also reveal significant decreases in fractional anisotropy (FA) with significant increases in apparent diffusion coefficient (ADC) values in compression lesions. FA values have higher accuracy than ADC values. Furthermore, strong correlations exist between FA values and indications of neurological severity, including the Japanese Orthopedic Association (JOA) score, the Oswestry Disability Index (ODI), and the Roland-Morris Disability Questionnaire (RDQ) in patients with lumbar disc herniation-induced radiculopathy. Most lumbar DTI has become 3T; 3T MRI has made it possible to take high-resolution DTI measurements in a short period of time. However, increased motion artifacts in the magnetic susceptibility effect lead to signal irregularities and image distortion. In the future, high-resolution DTI with reduced field-of-view may become useful in clinical applications, since visualization of nerve lesions and quantification of DTI parameters could allow more accurate diagnoses of lumbar nerve dysfunctions. Future translational studies will be necessary to successfully bring MR neuroimaging of lumbar nerve into clinical use.

Selective visualization of pelvic splanchnic nerve and pelvic plexus using readout-segmented echo-planar diffusion-weighted magnetic resonance neurography: A preliminary study in healthy male volunteers

PurposeTo evaluate the potential of readout-segmented echo-planar diffusion-weighted magnetic resonance neurography (RS-EPI DW-MRN) for the selective visualization of pelvic splanchnic nerve and pelvic plexus in healthy male volunteers. Materials and methodsInstitutional review board approval and written informed consent were obtained. RS-EPI DW-MRN images were acquired from thirteen healthy male volunteers aged 25–48 years between September 2013 and December 2013. For RS-EPI DW-MRN, the following parameters were used: spatial resolution, 1.1×1.1×2.5mm; b-value, 250s/mm2; number of readout-segments, seven; and acquisition time, 7min 45s. For qualitative assessment, two abdominal radiologists independently evaluated the visibility of the pelvic splanchnic nerves and pelvic plexuses bilaterally in each subject on oblique coronal thin-slab 10-mm-thick maximum intensity projection images and scored it with a 4-point grading scale (excellent, good, fair, poor). Both readers scored twice at 6-month intervals. Inter-observer and intra-observer variability were evaluated using Cohen’s quadratically weighted κ statistics. Image artifact level was scored on a 4-point grading scale by other two abdominal radiologists in order to evaluate the correlation between the nerve visibility and the severity of imaging artifacts using the Spearman’s correlation coefficient. ResultsQualitative grading showed the following success rate (number of nerves qualitatively scored as excellent or good divided by total number of nerves): reader 1 (first set), 73% (19/26); reader 2 (first set), 77% (20/26); reader 1 (second set), 81% (21/26); and reader 2 (second set), 77% (20/26). Inter-observer agreement between readers 1 and 2 was excellent: κ=0.947 (first set) and 0.845 (second set). Intra-observer agreement was also excellent: κ=0.810 (reader 1) and 0.946 (reader 2). The visibility of pelvic splanchnic nerve and pelvic plexus showed a moderate correlation with the image artifact level (ρ=0.54, p=0.004). ConclusionThis study demonstrated that RS-EPI DW-MRN is a promising approach for selectively visualizing the pelvic splanchnic nerve and pelvic plexus.

Diffusion-weighted magnetic resonance neurography for the diagnosis of carpal tunnel syndrome: a pilot study

To investigate the applicability of diffusion-weighted magnetic resonance neurography (DW-MRN) in the diagnosis of carpal tunnel syndrome (CTS). In total, 47 patients with CTS (69 wrists) and 19 normal participants (38 wrists) was included in this study. Cross-sectional area (CSA) and apparent diffusion coefficient (ADC) values of the median nerves in the carpal tunnel were determined using DW-MRN. Receiver operating characteristic (ROC) analysis was performed. No significant differences in age or body mass index (BMI) were observed between the control and CTS groups. DW-MRN imaging showed obvious hyperintensity in the lesions in CTS wrists, while other nerve regions were related to slight hyperintensity. Interobserver variability analysis indicated excellent agreement regarding both the CSA and ADC measurements for the control and CTS groups. Both the mean CSA and ADC values of the median nerves in carpal tunnel in the CTS group were significantly higher than the control group. According tothe ROC analysis, the CSA cut-off value was 11.7mm2, and sensitivity and specificity were66.7% and 89.5%, respectively. Conversely, the median nerve ADC cut-off value was 1.047×10-3mm2/s. The sensitivity and specificity were 91.3% and 76.3.9%, respectively. DW-MRN represents a highly reproducible diagnostic technique for CTS. The ADC value of median nerves in the carpal tunnel is significantly higher in CTS patients, which provides a potential powerful tool for the disease diagnosis.

Diffusion-weighted MR neurography for the assessment of brachial plexopathy in oncological practice.

BackgroundTo evaluate diffusion-weighted MR neurography (DW-MRN) for visualizing the brachial plexus and for the assessment of brachial plexopathy.Methods40 oncological patients with symptoms of brachial plexopathy underwent 1.5 T MRI using conventional MR sequences and unidirectional DW-MRN. The images were independently reviewed by two radiologists. Anatomic visualization of the brachial plexus was scored using a 5 point scale on conventional MR sequences and then combined with DW-MRN. A brachial plexus abnormality was also scored using a 5 point scale and inter-observer agreement determined by kappa statistics. Diagnostic accuracy for brachial plexopathy assessed by conventional MRI alone versus conventional MRI combined with DW-MRN was compared by ROC analysis using reference standards.ResultsDW-MRN significantly improved visualization of the brachial plexus compared with conventional MRI alone (P < 0.001). When assessing brachial plexopathy, inter-observer agreement was moderate for conventional MRI (kappa = 0.48) but good for conventional MRI with DW-MRN (kappa = 0.62). DW-MRN combined with conventional MRI significantly improved diagnostic accuracy in one observer (P < 0.05) but was similar in the other observer.ConclusionDW-MRN improved visualization of the brachial plexus. Combining DW-MRN with conventional MRI can improve inter-observer agreement and detection of brachial plexopathy in symptomatic oncological patients.

Application of diffusion-weighted MR neurography in nontraumatic upper limb nerve torsion

Objective To investigate the diffusion weighted MR neurography(DW-MRN) features of nontraumatic upper limb nerve torsion and evaluate the application value of DW-MRN. Methods Six patients (unilateral upper extremity) who underwent surgical treatment for nerve fascicle torsion were analyzed retrospectively. Spin echo T1WI, spin echo fat suppress T2WI, DW-MRN and ultrasound were performed in all 6 patients. The DW-MRN features were analyzed by two radiologists and compared with the clinical surgeries and the results of ultrasonagraphy. Results Six patients were accurately diagnosed preoperatively by using DW-MRN as having nerve fascicle torsions. Nineteen nerve torsions were found in DW-MRN and the result was consistent with the findings at surgery, sixteen nerve torsions were found in ultrasonography, but three were missed. The affected segmental nerve fascicles showed hypointensitity in T1WI and hyperintensitity in T2WI because of nerve fascicle edema. The lesion of nerve torsion was hypointense signal, and single or multi-segmental hourglass-like change was seen at DW-MRN. Conclusions The DW-MRN of nontraumatic upper limb nerve torsion has certain characteristics, and can display the location and number of nerve torsion clearly. DW-MRN features is helpful in the diagnosis, differential diagnosis of nontraumatic upper limb nerve torsion and guidethesurgery. Compared to ultrasonography, DW-MRN has certain advantages in resolution, field size and visualization of images. Key words: Radial nerve; Median nerve; Magnetic resonance imaging

Diffusion-Weighted MR Neurography of Extremity Nerves With Unidirectional Motion-Probing Gradients at 3 T: Feasibility Study

The objective of our study was to show the feasibility and performance of diffusion-weighted MR neurography (MRN) of extremity nerves with unidirectional motion-probing gradients at 3 T. Forty-seven healthy volunteers and 10 patients underwent diffusion-weighted MRN of extremity nerves with unidirectional motion-probing gradients (anterior-posterior direction only) on a 3-T unit. Images were displayed using a maximum-intensity-projection technique. Two radiologists blindly and independently evaluated the imaging quality of extremity nerves on diffusion-weighted MRN images using a 4-point grading scale, with 4 indicating excellent quality and 1 indicating poor quality, and evaluated the relation of the lesion to adjacent nerves in patients. In volunteers, the long trajectories of major extremity nerves, including the radial, median, ulnar, sciatic, tibial, and common peroneal nerves, could be visualized 3D on diffusion-weighted MRN images. The mean imaging quality scores of all nerves for observers 1 and 2 were 3.68 ± 0.70 (SD) and 3.70 ± 0.66, respectively. Interobserver agreement was good (κ = 0.774). In patients, there was no discrepancy in imaging quality scores between observers. Scores of all nerves were 2-4 except in two patients with neurofibromatosis and one patient who underwent imaging soon after surgery. The extent of the lesions and the relationship of the lesions to the adjacent nerves were clearly depicted on diffusion-weighted MRN images of all patients. This preliminary study shows that 3-T diffusion-weighted MRN with unidirectional motion-probing gradients is feasible for 3D visualization of major extremity nerves. Diffusion-weighted MRN may enable nerve depiction and allow assessment of the anatomic relationship between lesions with diffusion restriction and adjacent nerves.

Subtraction of unidirectionally encoded images for suppression of heavily isotropic objects (SUSHI) for selective visualization of peripheral nerves

IntroductionThe aim of this study was to introduce and assess a new magnetic resonance (MR) technique for selective peripheral nerve imaging, called “subtraction of unidirectionally encoded images for suppression of heavily isotropic objects” (SUSHI).MethodsSix volunteers underwent diffusion-weighted MR neurography (DW-MRN) of the brachial plexus, and seven volunteers underwent DW-MRN of the sciatic, common peroneal, and tibial nerves at the level of the knee, at 1.5 T. DW-MRN images with SUSHI (DW-MRNSUSHI) and conventional DW-MRN images (DW-MRNAP) were displayed using a coronal maximum intensity projection and evaluated by two independent observers regarding signal suppression of lymph nodes, bone marrow, veins, and articular fluids and regarding signal intensity of nerves and ganglia, using five-point grading scales. Scores of DW-MRNSUSHI were compared to those of DW-MRNAP using Wilcoxon tests.ResultsSuppression of lymph nodes around the brachial plexus and suppression of articular fluids at the level of the knee at DW-MRNSUSHI was significantly better than that at DW-MRNAP (P < 0.05). However, overall signal intensity of brachial plexus nerves and ganglia at DW-MRNSUSHI was significantly lower than that at DW-MRNAP (P < 0.05). On the other hand, signal intensity of the sciatic, common peroneal, and tibial nerves at the level of the knee at DW-MRNSUSHI was judged as significantly better than that at DW-MRNAP (P < 0.05).ConclusionThe SUSHI technique allows more selective visualization of the sciatic, common peroneal, and tibial nerves at the level of the knee but is less useful for brachial plexus imaging because signal intensity of the brachial plexus nerves and ganglia can considerably be decreased.Electronic supplementary materialThe online version of this article (doi:10.1007/s00234-010-0713-6) contains supplementary material, which is available to authorized users.

Diffusion-weighted MR neurography of the sacral plexus with unidirectional motion probing gradients

BackgroundThis technical note introduces diffusion-weighted (DW) MR neurography (MRN) of the sacral plexus with unidirectional motion probing gradients (MPGs).MethodsThis is compared with DW MRN with three-directional and six-directional MPGs.Results and conclusionThis paper indicates that DW MRN of the sacral plexus should be performed with unidirectional MPGs.

Morphological Analysis in Patients With Sciatica

A prospective observational study of patients with sciatica. We investigated the effectiveness of 3-dimensional high-spatial resolution diffusion-weighted MR neurography based on steady state free precession (3-dimensional diffusion-weighted steady-state free precession [DW-SSFP]) in the diagnosis of sciatica. Patients with sciatica challenge a physician who desires a precise diagnosis for the etiology of the pain. Direct imaging of the sciatic nerve with high resolution and high contrast may contribute to accurate localization and help to find the causes of sciatica and provide reliable information to clinicians in treatment choice. Thus, we supposed that 3-dimensional DW-SSFP method have the ability to confirm the etiologies of sciatica. The 3-dimensional DW-SSFP sequence was performed on 137 patients with sciatica and 32 patients in control group. The postprocessing techniques were used to generate images of lumbosacral plexus and sciatic nerve, and the images acquired were assessed based on the presence or absence of nerve abnormality. The certainty of identifying the lumbosacral plexus and main branches from all cases was determined in each of the reconstruction planes for each case individually and assessed by using a 3-score scale. All subjects were successfully performed. The sciatic nerve and its main branches were differentiated and a clear picture was obtained in all subjects. Compared with the control group, the presence of nerve root compression or increased T2 signal intensity changes can be observed in all patients. The mean score of certainty of identifying the sciatic nerve and main branches was 1.76 +/- 0.4, which indicate that the sciatic nerve and main branches can be identified with certainty. The 3-dimensional DW-SSFP MRI with high spatial and sufficient contrast is an excellent technique to define the nature of sciatica and assists in prognostication and possibly in management.

Diffusion-weighted MR Neurography of the Brachial Plexus: Feasibility Study

The University Medical Center Utrecht institutional review board approved this study, and informed consent was obtained from all subjects. The purpose of this study was to introduce and assess diffusion-weighted (DW) magnetic resonance (MR) neurography for imaging of the brachial plexus. DW MR neurographic images were displayed with a maximum intensity projection technique. DW MR neurography was evaluated in five healthy volunteers and five patients. DW MR neurography showed a long trajectory of the brachial plexus in all healthy volunteers. In all patients, DW MR neurography clearly showed the location of the disease. The proposed DW MR neurography technique can be used to obtain an overview image of the brachial plexus, with excellent conspicuity of the nerves and surrounding structures.