- Email: [email protected]
6. Diffusion tensor MRI study of the spinal cord in patients with multiple sclerosis
Society Proceedings / Clinical Neurophysiology 122 (2011) e1–e7
dermatomes were stimulated with two different temperatures (52 °C and individual pain threshold plus 3 °C). Results: Perception thresholds of warmth showed no differences between the dermatomes while pain threshold and pain rating to heat were significantly different between dermatomes. In the cervical dermatomes C6 and C8 pain ratings were reduced and pain thresholds increased (p < 0.05) which related to reduced CHEPs amplitudes. CHEPs latencies were significantly (p < 0.05) longer for more distal segments. Regarding age class differences CHEPs amplitudes (N2, P2; N2P2) and latencies (N2, P2) demonstrated significant (p < 0.05) effects. Discussion and conclusion: The combined quantitative and neurophysiological sensory assessment revealed significant differences of sensory function between cervical and trunk dermatomes. The diverse responses to heat stimulation in these dermatomes are most likely due to differences in receptor densities. These differences among segments should be concerned when investigating the sensory function of the spinothalamic tract. CHEPS as a segmental sensitive tool could complete the clinical testing of sensory thresholds to improve the assessments of the spino-thalamic tract in SCI. doi:10.1016/j.clinph.2010.10.011
6. Diffusion tensor MRI study of the spinal cord in patients with multiple sclerosis—J. von Meyenburg 1, B. Wilm 2, A. Weck 3, J. Petersen 4, E. Gallus 1, J. Mathys 3, E. Schätzle 1, K. von Meyenburg 5, N. Goebels 3, S. Kollias 1 (1 Institute of Neuroradiology, University Hospital, Zürich, Switzerland, 2 Institute of Neuroradiology, University Hospital, Institute for Biomedical Engineering, University & ETH, Zürich, Switzerland, 3 Department of Neurology, University Hospital, Zürich, Switzerland, 4 Spinal Cord Injury Center, Balgrist University Hospital, Zürich, Switzerland, 5 Zürich, Switzerland) Introduction: Diffusion tensor imaging (DTI) can potentially discern axonal loss in white-matter tissue and serve as a marker for loss of tissue integrity (demyelination, axonal degeneration) [1,2]. Limited resolution in spinal cord DWI has so far impeded focal evaluation of spinal cord tissue, i.e., the differentiation between grey and white matter. Furthermore, adequate image quality was achievable only at the cervical level of the spinal cord. Recent improvements in MR pulse sequence design have overcome these problems. Methods: Imaging was performed on a 3T Philips Achieva using a dedicated spine coil. DTI data of 28 volunteers and 41 patients with relapsing remitting MS (RRMS), secondary progressive MS (SPMS) or primary progressive MS (PPMS) (Table 1) were acquired at the cervical, thoracic and lumbar levels of the spinal cord. In each region six transverse slices were acquired using an outer volume suppressed
e3
reduced field of view single-shot EPI sequence [3,4]. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) maps were calculated. Diffusivity values were evaluated in the posterior white matter (PWM) in normal appearing spinal cord tissue, i.e., spinal cord tissue without T2-hyperintense lesions. Results: Mean fractional anisotropy in the posterior white matter (PWM) was highest in healthy subjects and lowest in the PPMS group (Table 1). ADC values were lowest in volunteers and highest in the RRMS group, respectively. In the patient groups the decrease of FA was statistically significant on cervical level and showed a trend on thoracic level as compared to healthy volunteers (Table 1). Conclusions: Correlation between diffusion anisotropy and axonal density [2] in spinal MS lesions has been observed by comparing MRI images and neuropathological findings. Based on these observations our results suggest that axonal degeneration is most prominent in the PPMS group. The highest ADC values were seen in the RRMS group which might indicate that the degree of myelin loss in the RRMS patients is most prominent [2]. The fact that the PWM FA difference between patients and the control group was highest at cervical level and decreasing when moving caudally (Table 1) might also reflect a decrease of inflammation in a cranio-caudal sense. This goes along with an observed decrease of T2-hyperintense lesions when moving caudally in the spinal cord [5]. Correlation between anatomical analysis with electrophysiological and clinical tests is ongoing. This study was supported by the Swiss Multiple Sclerosis Society. References Ohgiya Y et al. Eur Radiol ];17(10):2499–504. Mottershead JP et al. J Neurol ];250(11):1293–301. Wilm BJ et al. NMR Biomed ];26. Wilm BJ et al. Magn Reson Med ];57(3):625–30. Tartaglino LM et al. Radiology ];195(3):725–32. doi:10.1016/j.clinph.2010.10.012
7. Early muscle membrane dysfunction in porcine peritonitis— K.A. Ackermann 1, L. Brander 2, R Schröder 2, D. Tuchscherer 2, S.M. Jakob 2, J. Takala 2, W.J. Z’Graggen 3 (1 Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland, 2 Department of Intensive Care Medicine, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland, 3 Departments of Neurology and Neurosurgery, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland) Introduction: Critically ill patients often develop diffuse muscle weakness and failure to wean from mechanical ventilation. The most
Table 1
Groups
Volunteers
RRMS
SPMS
PPMS
All patients
Number Male/female Mean age ± SD years (range) Mean disease duration ± SD years (range) Mean FA ± SD, PWM, at cervical level 5 Mean FA ± SD, PWM, at thoracic level 5 Mean FA ± SD, PWM, at the lumbar enlargement Mean ADC ± SD, PWM, at cervical level 5 Mean ADC ± SD, PWM, at thoracic level 5 Mean ADC ± SD, PWM, at the lumbar enlargement
28 14/14 44.8 ± 17 (21–83)
15 5/10 43.2 ± 8.8 (29–60) 8.06 ± 5.28 (2–17) 0.67 ± 0.07 0.69 ± 0.07 0.68 ± 0.11 0.89 ± 0.10 0.90 ± 0.10 0.92 ± 0.18
14 9/5 54.4 ± 10.5 (42–74) 18.14 ± 11.6 (4–43) 0.64 ± 0.05 0.69 ± 0.07 0.68 ± 0.11 0.83 ± 0.10 0.90 ± 0.11 0.89 ± 0.18
12 8/4 57 ± 14.5 (32–74) 11.1 ± 5.16 (4–18) 0.61 ± 0.07 0.63 ± 0.06 0.64 ± 0.04 0.90 ± 0.09 0.87 ± 0.11 0.89 ± 0.79
41 22/19 51.1 ± 12.6 (29–74) 12.43 ± 9.34 (29–60) 0.64 ± 0.07 0.68 ± 0.06 0.65 ± 0.08 0.90 ± 0.09 0.87 ± 0.11 0.89 ± 0.08
0.71 ± 0.05 0.70 ± 0.06 0.66 ± 0.07 0.88 ± 0.09 0.86 ± 0.08 0.89 ± 0.08
RRMS, relapsing remitting MS; SPMS, secondary progressive MS; PPMS, primary progressive MS; FA, fractional anisotropy; ADC, apparent diffusion coefficient; PWM, posterior white matter.
dermatomes were stimulated with two different temperatures (52 °C and individual pain threshold plus 3 °C). Results: Perception thresholds of warmth showed no differences between the dermatomes while pain threshold and pain rating to heat were significantly different between dermatomes. In the cervical dermatomes C6 and C8 pain ratings were reduced and pain thresholds increased (p < 0.05) which related to reduced CHEPs amplitudes. CHEPs latencies were significantly (p < 0.05) longer for more distal segments. Regarding age class differences CHEPs amplitudes (N2, P2; N2P2) and latencies (N2, P2) demonstrated significant (p < 0.05) effects. Discussion and conclusion: The combined quantitative and neurophysiological sensory assessment revealed significant differences of sensory function between cervical and trunk dermatomes. The diverse responses to heat stimulation in these dermatomes are most likely due to differences in receptor densities. These differences among segments should be concerned when investigating the sensory function of the spinothalamic tract. CHEPS as a segmental sensitive tool could complete the clinical testing of sensory thresholds to improve the assessments of the spino-thalamic tract in SCI. doi:10.1016/j.clinph.2010.10.011
6. Diffusion tensor MRI study of the spinal cord in patients with multiple sclerosis—J. von Meyenburg 1, B. Wilm 2, A. Weck 3, J. Petersen 4, E. Gallus 1, J. Mathys 3, E. Schätzle 1, K. von Meyenburg 5, N. Goebels 3, S. Kollias 1 (1 Institute of Neuroradiology, University Hospital, Zürich, Switzerland, 2 Institute of Neuroradiology, University Hospital, Institute for Biomedical Engineering, University & ETH, Zürich, Switzerland, 3 Department of Neurology, University Hospital, Zürich, Switzerland, 4 Spinal Cord Injury Center, Balgrist University Hospital, Zürich, Switzerland, 5 Zürich, Switzerland) Introduction: Diffusion tensor imaging (DTI) can potentially discern axonal loss in white-matter tissue and serve as a marker for loss of tissue integrity (demyelination, axonal degeneration) [1,2]. Limited resolution in spinal cord DWI has so far impeded focal evaluation of spinal cord tissue, i.e., the differentiation between grey and white matter. Furthermore, adequate image quality was achievable only at the cervical level of the spinal cord. Recent improvements in MR pulse sequence design have overcome these problems. Methods: Imaging was performed on a 3T Philips Achieva using a dedicated spine coil. DTI data of 28 volunteers and 41 patients with relapsing remitting MS (RRMS), secondary progressive MS (SPMS) or primary progressive MS (PPMS) (Table 1) were acquired at the cervical, thoracic and lumbar levels of the spinal cord. In each region six transverse slices were acquired using an outer volume suppressed
e3
reduced field of view single-shot EPI sequence [3,4]. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) maps were calculated. Diffusivity values were evaluated in the posterior white matter (PWM) in normal appearing spinal cord tissue, i.e., spinal cord tissue without T2-hyperintense lesions. Results: Mean fractional anisotropy in the posterior white matter (PWM) was highest in healthy subjects and lowest in the PPMS group (Table 1). ADC values were lowest in volunteers and highest in the RRMS group, respectively. In the patient groups the decrease of FA was statistically significant on cervical level and showed a trend on thoracic level as compared to healthy volunteers (Table 1). Conclusions: Correlation between diffusion anisotropy and axonal density [2] in spinal MS lesions has been observed by comparing MRI images and neuropathological findings. Based on these observations our results suggest that axonal degeneration is most prominent in the PPMS group. The highest ADC values were seen in the RRMS group which might indicate that the degree of myelin loss in the RRMS patients is most prominent [2]. The fact that the PWM FA difference between patients and the control group was highest at cervical level and decreasing when moving caudally (Table 1) might also reflect a decrease of inflammation in a cranio-caudal sense. This goes along with an observed decrease of T2-hyperintense lesions when moving caudally in the spinal cord [5]. Correlation between anatomical analysis with electrophysiological and clinical tests is ongoing. This study was supported by the Swiss Multiple Sclerosis Society. References Ohgiya Y et al. Eur Radiol ];17(10):2499–504. Mottershead JP et al. J Neurol ];250(11):1293–301. Wilm BJ et al. NMR Biomed ];26. Wilm BJ et al. Magn Reson Med ];57(3):625–30. Tartaglino LM et al. Radiology ];195(3):725–32. doi:10.1016/j.clinph.2010.10.012
7. Early muscle membrane dysfunction in porcine peritonitis— K.A. Ackermann 1, L. Brander 2, R Schröder 2, D. Tuchscherer 2, S.M. Jakob 2, J. Takala 2, W.J. Z’Graggen 3 (1 Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland, 2 Department of Intensive Care Medicine, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland, 3 Departments of Neurology and Neurosurgery, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland) Introduction: Critically ill patients often develop diffuse muscle weakness and failure to wean from mechanical ventilation. The most
Table 1
Groups
Volunteers
RRMS
SPMS
PPMS
All patients
Number Male/female Mean age ± SD years (range) Mean disease duration ± SD years (range) Mean FA ± SD, PWM, at cervical level 5 Mean FA ± SD, PWM, at thoracic level 5 Mean FA ± SD, PWM, at the lumbar enlargement Mean ADC ± SD, PWM, at cervical level 5 Mean ADC ± SD, PWM, at thoracic level 5 Mean ADC ± SD, PWM, at the lumbar enlargement
28 14/14 44.8 ± 17 (21–83)
15 5/10 43.2 ± 8.8 (29–60) 8.06 ± 5.28 (2–17) 0.67 ± 0.07 0.69 ± 0.07 0.68 ± 0.11 0.89 ± 0.10 0.90 ± 0.10 0.92 ± 0.18
14 9/5 54.4 ± 10.5 (42–74) 18.14 ± 11.6 (4–43) 0.64 ± 0.05 0.69 ± 0.07 0.68 ± 0.11 0.83 ± 0.10 0.90 ± 0.11 0.89 ± 0.18
12 8/4 57 ± 14.5 (32–74) 11.1 ± 5.16 (4–18) 0.61 ± 0.07 0.63 ± 0.06 0.64 ± 0.04 0.90 ± 0.09 0.87 ± 0.11 0.89 ± 0.79
41 22/19 51.1 ± 12.6 (29–74) 12.43 ± 9.34 (29–60) 0.64 ± 0.07 0.68 ± 0.06 0.65 ± 0.08 0.90 ± 0.09 0.87 ± 0.11 0.89 ± 0.08
0.71 ± 0.05 0.70 ± 0.06 0.66 ± 0.07 0.88 ± 0.09 0.86 ± 0.08 0.89 ± 0.08
RRMS, relapsing remitting MS; SPMS, secondary progressive MS; PPMS, primary progressive MS; FA, fractional anisotropy; ADC, apparent diffusion coefficient; PWM, posterior white matter.