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Background and Purpose: Total spine MRIs are requested by the emergency department when focused imaging can not be ordered on the basis of history or clinical findings. However, their efficacy is not known. We assessed the following: 1) major radiologic and clinical outcomes of total spine MR imaging performed by the emergency department, and 2) whether the presence of a high-risk clinical profile and/or neurologic findings impacts the clinical outcomes., Materials and Methods: Total spine MRIs requested by the emergency department during a 28-month period were evaluated for major radiologic (cord compression, cauda equina compression, and other significant findings) and major clinical outcomes (hospital admission during the visit followed by an operation, radiation therapy, or intravenous antibiotics or steroids). Associations between a high-risk clinical profile (cancer, infection, coagulopathy) and/or the presence of neurologic findings and outcomes were assessed., Results: After we excluded trauma or nondiagnostic studies, 321/2047 (15.7%) MRIs ordered during study period were total spine MR imaging; 117/321 (36.4%) had major radiologic and 60/321 (18.6%) had major clinical outcomes (34/60 in <24 hours); and 58/117(49.6%) with major radiologic outcome were treated compared with 2/205 (1.0%) without (OR = 99, P  < .001). The presence of both a high-risk clinical profile and neurologic findings concurrently in a patient (142/321) increased the likelihood of major clinical outcomes during the same visit (OR = 3.1, P  < .001) and in <24-hours (OR = 2.6, P  = .01) compared with those with either a high-risk clinical profile or neurologic findings alone (179/321)., Conclusions: Total spine MR imaging ordered by our emergency department has a high radiologic and significant clinical yield. When a high-risk clinical profile and neurologic findings are both present in a patient, they should be prioritized for emergent total spine MR imaging, given the increased likelihood of clinical impact., (© 2020 by American Journal of Neuroradiology.)

Background and Purpose: Fast spin-echo short τ inversion recovery sequences have been very useful for MR imaging-guided deep brain stimulation procedures in Parkinson disease. However, high-quality fast spin-echo imaging deposits significant heat, exceeding FDA-approved limits when patients already have undergone deep brain stimulation and need a second one or a routine brain MR imaging for neurologic indications. We have developed a STIR sequence with an ultra-low specific absorption rate that meets hardware limitations and produces adequate tissue contrast in cortical and subcortical brain tissues for deep brain stimulation recipients., Materials and Methods: Thirteen patients with medically refractory Parkinson disease who qualified for deep brain stimulation were imaged at 1.5T with a fast spin-echo short τ inversion recovery sequence modified to meet conditional MR imaging hardware and specific absorption rate restrictions. Tissue contrast-to-noise ratios and implant localization were objectively and subjectively compared by 2 neuroradiologists, and image quality for surgical planning was assessed by a neurosurgeon for high and low specific absorption rate images., Results: The mean contrast-to-noise ratio for cerebral tissues without including the contrast-to-noise ratio for ventricular fluid was 35 and 31 for high and low specific absorption rate images. Subjective ratings for low specific absorption rate tissue contrast in 77% of patients were identical to (and in a few cases higher than) those of high specific absorption rate contrast, while the neurosurgical coordinates for fusing the stereotactic atlas with low specific absorption rate MR imaging were equivalent to those of the high specific absorption rate for 69% of patients., Conclusions: Patients with Parkinson disease who have already had a deep brain stimulation face a risk of neural injury if routine, high specific absorption rate MR imaging is performed. Our modified fast spin-echo short τ inversion recovery sequence conforms to very conservative radiofrequency safety limits, while it maintains high tissue contrast for presurgical planning, postsurgical assessment, and radiologic evaluations with greater confidence for radiofrequency safety., (© 2014 by American Journal of Neuroradiology.)

Background and Purpose: Spinal cord atrophy is a common feature of MS. However, it is unknown which cord levels are most susceptible to atrophy. We performed whole cord imaging to identify the levels most susceptible to atrophy in patients with MS versus controls and also tested for differences among MS clinical phenotypes., Materials and Methods: Thirty-five patients with MS (2 with CIS, 27 with RRMS, 2 with SPMS, and 4 with PPMS phenotypes) and 27 healthy controls underwent whole cord 3T MR imaging. The spinal cord contour was segmented and assigned to bins representing each C1 to T12 vertebral level. Volumes were normalized, and group comparisons were age-adjusted., Results: There was a trend toward decreased spinal cord volume at the upper cervical levels in PPMS/SPMS versus controls. A trend toward increased spinal cord volume throughout the cervical and thoracic cord in RRMS/CIS versus controls reached statistical significance at the T10 vertebral level. A statistically significant decrease was found in spinal cord volume at the upper cervical levels in PPMS/SPMS versus RRMS/CIS., Conclusions: Opposing pathologic factors impact spinal cord volume measures in MS. Patients with PPMS demonstrated a trend toward upper cervical cord atrophy. However patients with RRMS showed a trend toward increased volume at the cervical and thoracic levels, which most likely reflects inflammation or edema-related cord expansion. With the disease causing both expansion and contraction of the cord, the specificity of spinal cord volume measures for neuroprotective therapeutic effect may be limited.

Purpose: To investigate the correlation between diffusional anisotropy and developmental changes in anatomy, which include myelination, in central and peripheral nerves in an animal model by using quantitative diffusion magnetic resonance (MR) imaging and electron microscopy., Materials and Methods: In vivo transverse and longitudinal apparent diffusion coefficients (ADCs) of the optic and trigeminal nerves in 2-10-week-old rats were measured with MR imaging. Then the animals were sacrificed at each time point, and transverse and longitudinal sections of optic and trigeminal nerves were studied with electron microscopy., Results: In the optic nerve, the ADC parallel to the neurofibers increased with development and increased contemporaneously with myelination, while the ADC perpendicular to the nerve did not change. This resulted in a significant increase in diffusional anisotropy. There were no significant changes in ADCs in either direction in the trigeminal nerve. Longitudinal sections of optic nerve showed a marked change in the orientation of each fiber. As development proceeded, the axons, which initially followed tortuous courses, assumed straighter and more parallel orientations. Trigeminal nerves displayed straight parallel courses at 2 weeks that did not change over the study period., Conclusion: Changes in fiber anatomy in maturation from tortuous to straighter and more parallel orientation can account for changes in longitudinal ADC and in diffusional anisotropy.

Object: The aim of this study was to investigate the indications and treatment options in patients with lower-extremity neuropathies and radiculopathies caused by endometriosis., Methods: The authors identified five patients whose symptoms included catamenial pain, weakness, and sensory loss involving the sciatic and femoral nerves and multiple lumbosacral nerve roots. Radiographic studies supported the diagnosis of catamenial neuropathy or radiculopathy, but definitive diagnosis depended on surgical and pathological examination. Treatment of symptoms, including physical therapy and a course of antiinflammatory or analgesic medication, was not helpful. Patients responded favorably to hormonal therapy. Laparoscopy or open exploration for extrapelvic lesions was performed for diagnosis or for treatment when hormone therapy failed. Pain and sensory symptoms responded well to therapy. Weakness improved, but never recovered completely., Conclusions: Catamenial neuropathy or radiculopathy should be considered when evaluating reproductive-age women with recurring focal neuropathic leg pain, weakness, and sensory loss.