High-Resolution 3D versus Standard-Resolution 2D T2-Weighted Turbo Spin Echo MRI for the Assessment of Lumbar Nerve Root Compromise.

Radiculopathy can be caused by nerve root irritation and nerve root compression at the level of the lateral recess or at the level of the intervertebral foramen. T2-weighted (T2w) MRI is considered essential to evaluate the nerve root and its course, starting at the lateral recess through the intervertebral foramen to the extraforaminal space. With the introduction of novel MRI acceleration techniques such as compressed SENSE, standard-resolution 2D T2w turbo spin echo (TSE) sequences with a slice-thickness of 3-4 mm can be replaced with high-resolution isotropic 3D T2w TSE sequences with sub-millimeter resolution without prolonging scan time. With high-resolution 3D MRI, the course of the nerve root can be visualized more precisely due to a detailed depiction of the anatomical situation and less partial volume effects, potentially allowing for a better detection of nerve root compromise. In this intra-individual comparison study, 55 patients with symptomatic unilateral singular nerve root radiculopathy underwent MRI with both 2D standard- and 3D high-resolution T2w TSE MRI sequences. Two readers graded the degree of lumbar lateral recess stenosis and lumbar foraminal stenosis twice on both image sets using previously validated grading systems in an effort to quantify the inter-readout and inter-sequence agreement of scores. Inter-readout agreement was high for both grading systems and for 2D and 3D imaging (Kappa = 0.823-0.945). Inter-sequence agreement was moderate for both lumbar lateral recess stenosis (Kappa = 0.55-0.577) and lumbar foraminal stenosis (Kappa = 0.543-0.572). The percentage of high degree stenosis with nerve root deformity increased from 16.4%/9.8% to 41.8-43.6%/34.1% from 2D to 3D images for lateral recess stenosis/foraminal stenosis, respectively. Therefore, we show that while inter-readout agreement of grading systems is high for both standard- and high-resolution imaging, the latter outperforms standard-resolution imaging for the visualization of lumbar nerve root compromise.

Global incidence of spinal perineural Tarlov's cysts and their morphological characteristics: a meta-analysis of 13,266 subjects.

BACKGROUND: Spinal perineural Tarlov's cysts (TCs) are considered incidental findings that occasionally might exert pressure upon nerve roots and correspond with patients' signs and symptoms. Purpose of this meta-analysis is to deliver global incidence and characteristics (location, size, and shape) of TCs. METHODS: Following PRISMA checklist, all major databases were searched by two authors for radiologic studies reporting incidence and morphologic features (location, size, and shape) of TCs. Anatomical Quality Assessment tool was applied for risk of bias evaluation. Meta-analysis of random-effects model was employed. Subgroup analysis for regional distribution, gender, sacral levels, age, correspondence with symptoms, and persistent genital arousal disorder (PGAD) were planned ahead. RESULTS: 22 radiologic studies of level 3 evidence involving 13,266 subjects were included. Global pooled prevalence of TCs was 4.18% (95% CI 2.47-6.30). Mean pooled sagittal diameter was 11.86 mm (95% CI 10.78-12.93). Sacral cysts strongly prevailed over the other segments. Of the sacral, S2 level was the most common (46.7% [95% CI 29.4-60.5]). Geographically, the highest incidence was found in Europe (6.07% [95% CI 1.49-13.00]), followed by North America (3.82% [95% CI 0.49-9.44]), and Asia (3.33% [95% CI 1.52-5.75]). TCs were more common in women than in men (5.84% vs 3.03%, p < 0.001, test of homogeneity, χ2). Subjects with PGAD had incidence of 37.87% (95% CI 2.45-81.75). TCs in pediatric population are rare-0.53% (95% CI 0.02-1.51). 15.59% of TCs corresponded with symptoms. CONCLUSIONS: Spinal perineural (Tarlov) cysts are found in a minority of population. S2 level of the sacral bone is affected most frequently. There is female predominance. Correspondence with symptoms is seen in less than one-fifth of TCs. Studies with stronger evidence level are needed to corroborate the results. The purported high incidence in PGAD requires confirmation in case-control studies for the risk-ratio calculation.

Functional Assessment of Lumbar Nerve Roots Using Coronal-plane Single-shot Turbo Spin-echo Diffusion Tensor Imaging.

We investigated the usefulness of diffusion tensor imaging using single-shot turbo spin-echo sequence (TSE-DTI) in detecting the responsible nerve root by multipoint measurements of fractional anisotropy (FA) values. Five patients with bilateral lumbar spinal stenosis showing unilateral neurological symptoms were examined using TSE-DTI. In the spinal canal, FA values in the symptomatic side were lower than those in the asymptomatic side. TSE-DTI using multipoint measurements of FA values can differentiate the responsible lumbar nerve root.

Ultrasound assessment of peripheral nerve pathology in neurofibromatosis type 1 and 2.

OBJECTIVE: The neurofibromatoses (NF) type 1 and 2 are hereditary tumor predisposition syndromes caused by germline mutations in the NF1 and NF2 tumor suppressor genes. In NF1 and 2, peripheral nerve tumors occur regularly. For further characterizing nerve ultrasound was performed in patients with NF1 and 2. METHODS: Patients with established diagnosis of NF1 (n=27) and NF2 (n=10) were included. Ultrasound of peripheral nerves and cervical roots was performed during routine follow-up visits. Healthy volunteers were studied for comparison. RESULTS: In patients with NF1, median cross-sectional area (CSA) of most nerves was significantly increased compared to controls and to NF2 due to generalized plexiform tumors, which arose out of multiple fascicles in 23 of 27 patients (85%). These were often accompanied by cutaneous or subcutaneous neurofibromas. In NF2, the overall aspect of peripheral nerves consisted of localized schwannomas (80%) and, apart from that, normal nerve segments. CONCLUSION: Nerve ultrasound is able to visualize different nerve pathologies in NF1 and NF2. It is a precise and inexpensive screening method for peripheral nerve manifestation in neurofibromatosis and should be considered as the first choice screening imaging modality for all peripheral nerves within reach of non-invasive ultrasound techniques. SIGNIFICANCE: Ultrasound patterns of peripheral nerve pathologies are described for the first time in a large cohort of patients with NF1 and NF2. It is a suitable screening tool and enables targeted MRI analysis.

Ultrasonography has a diagnostic value in the assessment of cervical radiculopathy: A prospective pilot study.

OBJECTIVE: This study investigated the diagnostic accuracy of the difference in the cross-sectional areas (CSAs) of affected cervical nerve roots (NRs) for diagnosing cervical radiculopathy (CR). METHODS: In total, 102 CR patients and 219 healthy volunteers were examined with ultrasound. The CSA of the cervical NR at each level was measured on the affected side and the contralateral side in CR patients by blinded ultrasonographic technicians. The difference between the CSAs of CR patients and normal volunteers and the difference in the laterality of CSA at the same affected level (ΔCSA) were calculated for each cervical level. RESULTS: The CSAs of the affected NRs in CR patients were significantly larger than those of the unaffected NRs in CR patients and those of the control group at the C5, C6 and C7 levels (P<0.005). ΔCSA was also significantly larger in the CR group at all levels (P<0.001). A receiver operating characteristic analysis demonstrated that the threshold values were 9.6 mm2 (CSA) for C5NR and 15 mm2 for both C6NR and C7NR. CONCLUSIONS: This study revealed that the CSAs of affected NRs were enlarged and that the laterality of the CSA (ΔCSA) was greater in CR patients than in control patients. KEY POINTS: • Cervical radiculopathy is diagnosed through ultrasonographic measurement of the CSAs. • The CSAs of affected nerve roots were significantly enlarged. • The ΔCSA in the CR group was significantly higher than in the control group. • Diagnostic CSA and ΔCSA thresholds were identified.

2015 Young Investigator Award Winner: Cervical Nerve Root Displacement and Strain During Upper Limb Neural Tension Testing: Part 1: A Minimally Invasive Assessment in Unembalmed Cadavers.

STUDY DESIGN: A cross-sectional cadaveric examination of displacement and strain measured at the level of the cervical nerve roots during upper limb neural tension testing (ULNTT) with median nerve bias. OBJECTIVE: To determine the displacement and strain of cervical nerve roots C5-C8 during ULNTT with minimal disruption of surrounding tissues. SUMMARY OF BACKGROUND DATA: Clinical examination of neural pathology involving cervical nerve roots is difficult because of the transient nature of pathologies, such as cervical radiculopathy, entrapment neuropathies, and thoracic outlet syndrome. Cadaveric studies have demonstrated significant displacement and strain in lumbosacral nerve roots during neurodynamic testing of the lower extremity. Examination into the biomechanical behaviors of cervical nerve roots during ULNTT has not been performed. METHODS: Eleven unembalmed cadavers were positioned supine as though undergoing ULNTT. Radiolucent markers were implanted into cervical nerve roots C5-C8. Posteroanterior fluoroscopic images were captured at resting and ULNTT positioning. Images were digitized and displacement and strain were calculated. RESULTS: ULNTT resulted in significant inferolateral displacement (average, 2.16 mm-4.32 mm, P < 0.001) of cervical nerve roots C5-C8. There was a significant difference in inferolateral displacement between the C5 and C6 nerve roots (3.15 mm vs. 4.32 mm, P = 0.009). ULNTT resulted in significant strain (average, 6.80%-11.87%, P < 0.001) of cervical nerve roots C5-C8. There was a significant difference in strain between the C5 and C6 nerve roots (6.60% vs. 11.87%, P = 0.03). CONCLUSION: ULNTT caused significant inferolateral displacement and strain in cervical nerve roots C5-C8. These results provide the mechanical foundation for the use of ULNTT in clinical evaluation of pathology in the cervical region, such as in cervical radiculopathy, entrapment neuropathies, and thoracic outlet syndrome. LEVEL OF EVIDENCE: 2.

Cost comparison of nerve root infiltration of the lumbar spine under MRI and CT guidance.

OBJECTIVES: To compare the costs of CT- and MR-guided lumbosacral nerve root infiltration for minimally invasive treatment of low back pain and radicular pain. METHODS: Ninety patients (54 men, 36 women; mean age, 45.5 ± 12.8 years) underwent MR-guided single-site periradicular lumbosacral nerve root infiltration with 40 mg of triamcinolone acetonide. A further 91 patients (48 men, 43 women; mean age, 59.1 ± 13.8 years) were treated under CT fluoroscopy guidance. Prorated costs of equipment use (purchase, depreciation and maintenance), staff costs based on involvement times and expenditure for disposables were identified for MR- and CT-guided procedures. RESULTS: Mean intervention time was 20.6 min (14-30 min) for MR-guided and 14.3 min (7-32 min) for CT-guided treatment. The average total costs per patient were €177 for MR-guided and €88 for CT-guided interventions. These consisted of (MR/CT guidance) €93/29 for equipment use, €43/35 for staff and €41/24 for disposables. CONCLUSIONS: Lumbosacral nerve root infiltration using MRI guidance is still about twice as expensive as infiltration using CT guidance. Given the advantages of no radiation exposure and possible future decrease in prices for MRI devices and MR-compatible injection needles, MR-guided nerve root infiltration may become a promising alternative to the CT-guided procedure. KEY POINTS: • MR-guided nerve root infiltration therapy is now technically and clinically established. • Costs using MRI guidance are still about double those for CT guidance. • MR guidance involves no radiation exposure to patients and personnel. • MR-guided nerve root infiltration may become a promising alternative to CT.

[Neurolymphomatosis: diagnosis of extension and assessment of response to treatment with PET-CT]. / Neurolinfomatosis: diagnóstico de extensión y valoración de la respuesta al tratamiento mediante PET-TAC.

Neurolymphomatosis is a rare neurological manifestation of non-Hodgkin's lymphoma (NHL) and it may be its first and sole manifestation. Diagnosis is often difficult and nerve biopsy is generally required. However, this it is not always possible to perform or is not conclusive. We present the case of a 66-year-old woman diagnosed with giant B-cell NHL. After 6 cycles of chemotherapy, imaging and molecular biology techniques showed complete remission. At four months after treatment, the patient complained of low back pain of radicular distribution. CT and MRI imaging showed signs of lymphoproliferative activity of L5 and also lesions to thoracic nerve roots. A PET-CT was requested in order to complete the diagnosis and plan the treatment. Imaging confirmed the presence of tumor recurrence with neurolymphomatosis and also indicated lesions on the chest and abdominal level. Thus, it was decided to start a new line of chemotherapy, without performing the histological study through biopsy. This case illustrates the important role played by PET-CT imaging in neurolymphomatosis diagnosis. This technique can help the patient avoid more aggressive procedures, such as a biopsy, and can also be useful in the follow-up and assessment of the treatment response to NHL-diagnosed patients.

The radiologic assessment for a lumbar disc herniation.

With magnetic resonance imaging and computed tomography, there now are two excellent diagnostic imaging modalities to detect noninvasively the presence of lumbar disc abnormalities and to follow the natural history of pathologic changes of a disc, with or without therapeutic interventions. The clinical significance of the information provided by these two imaging methods can be determined only by precise correlation of the results of a magnetic resonance imaging or computed tomography study to a patient's history, physical examination, and other diagnostic tests. With controlled prospective clinical studies, it may be possible to learn what type of abnormal changes detected on a magnetic resonance imaging or computed tomography study may have prognostic value in predicting patient outcome.

Neuroradiologic and electrophysiologic assessment of cervical spondylotic amyotrophy.

Dissociated motor loss due to cervical spondylosis and disc herniation was evaluated in 10 patients who presented with left deltoid paresis in the absence of sensory deficits or myelopathy. All of these cases underwent cervical anterior decompression. Based on magnetic resonance imaging, computed tomography myelography, and computed tomography discography, patients were divided into two pathologic types: The first showed focal bony spur and disc herniation with axial cord rotation and nerve root compression, and the second demonstrated ventral cord flattening. Electrophysiologic studies included evoked spinal potentials, motor evoked potentials, and evoked muscle action potentials. Motor evoked potentials, recorded epidurally from the ventral aspect of the thecal sac and the nerve root within the anterior discectomy or vertebrectomy sites, proved clinically most useful. Combining the latest available neuroradiologic and electrophysiologic information, 4 types of neural injury associated with deltoid pareses were identified in the 10 patients. The first included isolated C5 nerve root lesions; the second, C6 nerve root lesions; the third, both C5 and C6 nerve root lesions, and finally, intrinsic cord pathology.

Radicular avulsion resulting from spinal injury: assessment of diagnostic modalities.

The diagnostic utility of imaging techniques in injuries to the intramedullary and subarachnoid portions of the brachial plexus, with possibly complete avulsion of one or more nerve roots from the spinal cord and extramedullary meningocoele was compared in 18 patients studied by unenhanced computed tomography (CT), cervical myelography, myelographic CT (MCT) and magnetic resonance imaging (MRI). Emphasis was placed on the lesions of the subarachnoid roots. CM was the only diagnostic modality to show avulsion of 18 nerve roots and their levels in 8 patients (100% = gold standard), and to verify 2 incomplete avulsions. MCT reliably revealed 8 of 18 (45%) and MRI 1 out of 18 (6%) avulsions. Myelography with MCT showed intact subarachnoid nerve roots in 10 additional patients. MRI and MCT (16 out of 16 = 100%) were superior to myelography (14/16 = 88%) for demonstrating 16 traumatic meningocoeles in 8 patients; follow-up MRI (6-24 months) showed no increase in their size. We recommend a subsequent CT to role out fracture to the spinal column; MRI should provide significant information concerning oedema or haemorrhage in the spinal cord. Myelography with segmental MCT is performed to differentiate pre- from post-ganglionic lesions, data which are essential for deciding whether exploration of the plexus or a motor substitution operation is indicated.

Intracranial iohexol-distribution following cervical myelography, postmyelographic registration of adverse effects, psychometric assessment and electroencephalographic recording.

Cervical myelography (CM) was taken from 14 cases with cervical root-compression symptoms. Prior to myelography, there was complete cranial CT registration to assess the subarachnoid, intraventricular, subcortical and periventricular densities. Control scans at 3,6,24 and 48 h following myelography disclosed intracranial contrast medium at level of basal cisterns, the fourth ventricle and fissura Sylvii. Nine and 11 patients, respectively, had enhancement in the third and lateral ventricles. All patients had subcortical enhancement, and 9 patients had periventricular enhancement; at the 3-h control CT after myelography a minor subcortical edema was disclosed, which declined during the following hours. Two days after myelography, a minimal residual contrast was disclosed subcortically at the level of fissura Sylvii and in the subarachnoid space at the level of fissura Sylvii and the convexity. Hence, we recommend, that diagnostic cranial CT is performed before or postponed until 3 days after cervical myelography. The patients were questioned about adverse effects, and they underwent psychometric assessment and EEG-recordings: 11 had adverse effects, chiefly mild and exclusively transient, without sequelae. Three patients had no side effect. The psychometric assessment, however, disclosed pronounced deterioration in all patients at test 28 h after myelography, especially marked in the verbal paired associates test, however these disturbances were totally absent at retest one week later. No EEG-abnormalities developed; consistently, no patient had seizures. In conclusion, following CM iohexol is taken up by the brain parenchyma, gradually disappearing within 48 h, during which time a brain CT will be disturbed. During the same period some deterioration of psychometric tests may be found.

Comparing the cost of spinal MR with conventional myelography and radiculography.

All spinal magnetic resonance imaging examinations carried out during a three month period were analysed retrospectively in order to determine the clinical reasons for the scan requests. Technical details of the examinations they received and the clinical profiles formed a data set which revealed 10 separate "Clinical groups" for management purposes. Hardware, salary and expendables were costed as though the imaging unit had been sited within a National Health Service radiology department. A spread sheet was designed capable of calculating costs per patient for a variety of types of working week and of different staffing structures, sensitive to the mixture of clinical groups referred for examination. The spreadsheet also accomodated straight line depreciation for hardware value and interest rates for borrowed capital. A second, prospectively observed, sample of spinal MR examinations was used to improve the accuracy of the timing of the length of patient examinations. Costs were compared with those for patients submitted for myelography and radiculography at the adjacent hospital during the same period. The comparison indicated that spinal MR was less costly than myelography and radiculography. The most important element of the extra cost of myelography related to the need to admit patients to hospital for at least one night for this examination because of the likelihood of headache and other common (though usually minor) complications following lumbar puncture and/or the injection of contrast medium. From the limited information that it was possible to obtain in the period of follow up, it appeared that MR had either been superior or equivalent to myelography or radiculography in all the clinical groups of patients where both could be tested. There were a number of groups in which no myelograms had been requested, presumably because clinical suspicions had pointed toward conditions like tumours, developmental abnormalities and demyelinating diseases in which neurologists and neurosurgeons have already made up their minds about the superiority of MR.

Traumatic lumbosacral nerve root meningoceles. The value of myelography, CT and MRI in the assessment of nerve root continuity.

A case of traumatic lumbar meningoceles at four levels in combination with total and partial nerve root avulsion and with preservation of a nerve root is reported. Several diagnostic imaging techniques (myelography, CT, myelo-CT and MRI) are compared and their value in demonstrating the continuity of the nerve roots is discussed. MRI could assess the continuity of a nerve root in a traumatic meningocele, not demonstrable by myelography or myelo-CT. The combination of myelography, myelo-CT and MRI is likely to provide a complete diagnostic evaluation of nerve root lesions.

[Irradiation of the patient and its costs in the usual diagnostic procedures for disk hernia. Radiculography, spinal phlebography and tomodensitometry]. / Etude de l'irradiation du patient et du coût dans les procédures diagnostiques usuelles des hernies discales. Radiculographie, phlébographie rachidienne et tomodensitométrie.

Three methods are currently employed for the diagnosis of sciatica due to disc lesions: radiculography, spinal phlebography, and computed tomography. Though their indications vary according to the author, it seemed worthwhile to compare radiation delivered by each of them, because of the often young age of the patients. Dosimetric studies using a Rando Phantom enabled calculation of doses to the skin, spinal cord, and gonads. Results indicated that low doses were delivered by the scanner, relatively high doses by spinal phlebography, and intermediate doses by radiculography. These findings suggest that the initial examination preoperatively in cases of simple sciatica due to herniated disc should be a CT scan whenever possible. Phlebography, on the contrary, and particularly in young women, should be used only exceptionally, as a result of the high doses delivered to the ovaries even during technically simple explorations.