Reinhard Schumacher1, Detlef Richter. 1. Department of Pediatric Radiology, Hospital for Sick Children, University of Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany. schumach@mail.uni-mainz.de
Abstract
BACKGROUND: Movements of the spinal cord are induced by arterial pulsation and breathing. OBJECTIVE: The aim of this study was to analyse these oscillations in more detail and to classify them using one-dimensional fast Fourier transformation (1D-FFT). MATERIALS AND METHODS: A total of 153 M-mode studies in 53 patients (age 1 month to 14 years) were undertaken using a 5-MHz linear transducer (B- and M-mode). 1D-FFT was applied to the M-mode areas of digitized images. RESULTS: 1D-FFT shows characteristic patterns of spectra for groups of normal, reduced and missing cord motility. For normal cord motility, 1D-FFT peak frequency corresponded to the heart rate, and additional four to five harmonic maxima up to 11 Hz could be found. Reduced cord motility was characterised by one to three harmonic maxima; an immobile cord showed only zero to one maximum. The maximum speed of transverse motion of the neural structures in the lumbar region reached 25 mm/s. CONCLUSIONS: Using 1D-FFT, characteristic frequency patterns of spinal cord motions can be analysed. In patients with meningomyelocoele individual classification of cord motility is possible. This method of analysis may assist with recognising those at risk of developing secondary tethered cord syndrome.
BACKGROUND: Movements of the spinal cord are induced by arterial pulsation and breathing. OBJECTIVE: The aim of this study was to analyse these oscillations in more detail and to classify them using one-dimensional fast Fourier transformation (1D-FFT). MATERIALS AND METHODS: A total of 153 M-mode studies in 53 patients (age 1 month to 14 years) were undertaken using a 5-MHz linear transducer (B- and M-mode). 1D-FFT was applied to the M-mode areas of digitized images. RESULTS: 1D-FFT shows characteristic patterns of spectra for groups of normal, reduced and missing cord motility. For normal cord motility, 1D-FFT peak frequency corresponded to the heart rate, and additional four to five harmonic maxima up to 11 Hz could be found. Reduced cord motility was characterised by one to three harmonic maxima; an immobile cord showed only zero to one maximum. The maximum speed of transverse motion of the neural structures in the lumbar region reached 25 mm/s. CONCLUSIONS: Using 1D-FFT, characteristic frequency patterns of spinal cord motions can be analysed. In patients with meningomyelocoele individual classification of cord motility is possible. This method of analysis may assist with recognising those at risk of developing secondary tethered cord syndrome.
Authors: Murat Alp Oztek; Nina A Mayr; Mahmud Mossa-Basha; Matthew Nyflot; Patricia A Sponseller; Wei Wu; Christoph P Hofstetter; Rajiv Saigal; Stephen R Bowen; Daniel S Hippe; William T C Yuh; Robert D Stewart; Simon S Lo Journal: Neurosurgery Date: 2020-11-16 Impact factor: 4.654