Free
Correspondence  |   April 2003
The Use of Three-dimensional Computed Tomography to Visualize Thoracic Epidural Catheters
Author Affiliations & Notes
  • Hsiang-Ning Luk, M.D., M.S., Ph.D.
    *
  • *Chang-Gung Memorial Hospital, Linkou, Taoyuan, Taiwan.
Article Information
Correspondence
Correspondence   |   April 2003
The Use of Three-dimensional Computed Tomography to Visualize Thoracic Epidural Catheters
Anesthesiology 4 2003, Vol.98, 1031-1032. doi:
Anesthesiology 4 2003, Vol.98, 1031-1032. doi:
To the Editor:—
Thoracic epidural catheterization was implemented in a 62-yr-old woman scheduled for subtotal gastrectomy. A FlexTip Plus® epidural catheter (single end hole; Arrow International, Reading, PA) was inserted at the T9–T10 intervertebral space and directed cephalad for 5 cm. With the patient's consent, a 10-cm slab of a thin-cut spiral computed tomography (CT) scan was obtained through T6–T12 with 1-mm collimation at a pitch of 2,140 kVp and 160 mA and with a 13-cm field of view (HiSpeed Advantage scanner; GE Medical Systems, Milwaukee, WI).
The raw data were processed with a 0.5-mm overlap using the GE Advantage workstation (DentaScan, GE Medical Systems). The axial transverse section of the CT image demonstrated the existence of a catheter in the epidural space (fig. 1A). With an oblique view, the path of the catheter in the epidural space was displayed with multiplanar reconstruction (fig. 1B) or a three-dimensional surface-shaded display (fig. 2). There was no kinking or knotting of the catheter despite the curved path in the epidural space.
Fig. 1. (A  ) An axial computed tomography image shows the epidural catheter between the spinal lamina and the dural sac. The epidural catheter contains radiopaque metal spring coils. (B  ) A multiplanar reconstructed image of the lower thoracic spine in an oblique coronal section shows the complex but smooth, looping course of the epidural catheter (arrow  ), without kinking.
Fig. 1. (A 
	) An axial computed tomography image shows the epidural catheter between the spinal lamina and the dural sac. The epidural catheter contains radiopaque metal spring coils. (B 
	) A multiplanar reconstructed image of the lower thoracic spine in an oblique coronal section shows the complex but smooth, looping course of the epidural catheter (arrow 
	), without kinking.
Fig. 1. (A  ) An axial computed tomography image shows the epidural catheter between the spinal lamina and the dural sac. The epidural catheter contains radiopaque metal spring coils. (B  ) A multiplanar reconstructed image of the lower thoracic spine in an oblique coronal section shows the complex but smooth, looping course of the epidural catheter (arrow  ), without kinking.
×
Fig. 2. Surface display images (three-dimensional) of the epidural catheter in the thoracic epidural space. The arrows depict the path of the catheter. The laminae were removed during the reconstruction process.
Fig. 2. Surface display images (three-dimensional) of the epidural catheter in the thoracic epidural space. The arrows depict the path of the catheter. The laminae were removed during the reconstruction process.
Fig. 2. Surface display images (three-dimensional) of the epidural catheter in the thoracic epidural space. The arrows depict the path of the catheter. The laminae were removed during the reconstruction process.
×
A substantial incidence of failed or unilateral epidural block may be due to the complexity of the epidural space. 1 When looping, kinking, entrapment, or knotting of epidural catheters occurs, it is not easy to visualize the path of the radiopaque catheter within the epidural space. 2,3 Although conventional radiography, 4,5 ultrasonographic imaging, 6 epidurography with contrast medium, 7 CT, 8–10 or magnetic resonance imaging 11 might be useful, a potential allergic reaction to contrast medium, interference with metal coils, or blockade or occlusion of the epidural catheter could still be problematic. Thin-cut volumetric CT scanning, coupled with two-dimensional multiplanar or three-dimensional model reconstruction, has been used for evaluation of the upper airway anatomy. 12 
Given the exquisite tissue contrast of CT in displaying the epidural space, its potential in the evaluation of a problematic epidural catheter has never been explored. An axial scan shows the exact location of the catheter in the epidural space and thus is useful in detecting malposition. With two-dimensional multiplanar and three-dimensional surface display models, the course of the catheter in the epidural space is depicted. In conclusion, three-dimensional CT imaging appears to be a novel tool to visualize the position and path of an epidural catheter.
References
Hogan QH: Lumbar epidural anatomy: A new look by cryomicrotome section. A nesthesiology 1991; 75: 767–75Hogan, QH
Hsin ST, Chang FC, Tsou MY, Liao WW, Lee TY, Lui PW, Luk HN: Inadvertent knotting of a thoracic epidural catheter. Acta Anaesthesiol Scand 2001; 45: 255–7Hsin, ST Chang, FC Tsou, MY Liao, WW Lee, TY Lui, PW Luk, HN
Renehan EM, Peterson RA, Penning JP, Rosaeg OP, Chow D: Visualization of a looped and knotted epidural catheter with a guidewire. Can J Anaesth 2000; 47: 329–33Renehan, EM Peterson, RA Penning, JP Rosaeg, OP Chow, D
Muneyuki M, Shirai K, Inamoto A: Roentgenographic analysis of the positions of catheters in the epidural space. A nesthesiology 1970; 33: 19–24Muneyuki, M Shirai, K Inamoto, A
Hendriks GW, Hasenbos MA, Gielen MJ, van Egmond J, Barentsz JO: Evaluation of thoracic epidural catheter position and migration using radio-opaque catheters. Anaesthesia 1997; 52: 457–9Hendriks, GW Hasenbos, MA Gielen, MJ van Egmond, J Barentsz, JO
Grau T, Leipold RW, Delorme S, Martin E, Motsch J: Ultrasound imaging of the thoracic epidural space. Reg Anesth Pain Med 2002; 27: 200–6Grau, T Leipold, RW Delorme, S Martin, E Motsch, J
Seeling W, Tomczak R, Merk J, Mrakovcic N: CT-epidurography. A comparison of conventional and CT-epidurography with contrast medium injection through a thoracic peridural catheter. Anaesthesist 1995; 44: 24–36Seeling, W Tomczak, R Merk, J Mrakovcic, N
Harrison GR: Topographical anatomy of the lumbar epidural region: An in vivo study using computerized axial tomography. Br J Anaesth 1999; 83: 229–34Harrison, GR
Ghia JN, Arora SK, Castillo M, Mukherji SK: Confirmation of location of epidural catheters by epidural pressure waveform and computed tomography cathetergram. Reg Anesth Pain Med 2001; 26: 337–41Ghia, JN Arora, SK Castillo, M Mukherji, SK
Hogan Q: Epidural catheter tip position and distribution of injectate evaluated by computed tomography. A nesthesiology 1999; 90: 964–70Hogan, Q
Westbrook JL, Renowden SA, Carrie LES: Study of the anatomy of the extradural region using magnetic resonance imaging. Br J Anaesth 1993; 71: 495–8Westbrook, JL Renowden, SA Carrie, LES
Kanaya N, Kawana S, Watanabe H, Niiyama Y, Niiya T, Nakayama M, Namiki A: The utility of three-dimensional computed tomography in unanticipated difficult endotracheal intubation. Anesth Analg 2000; 91: 752–4Kanaya, N Kawana, S Watanabe, H Niiyama, Y Niiya, T Nakayama, M Namiki, A
Fig. 1. (A  ) An axial computed tomography image shows the epidural catheter between the spinal lamina and the dural sac. The epidural catheter contains radiopaque metal spring coils. (B  ) A multiplanar reconstructed image of the lower thoracic spine in an oblique coronal section shows the complex but smooth, looping course of the epidural catheter (arrow  ), without kinking.
Fig. 1. (A 
	) An axial computed tomography image shows the epidural catheter between the spinal lamina and the dural sac. The epidural catheter contains radiopaque metal spring coils. (B 
	) A multiplanar reconstructed image of the lower thoracic spine in an oblique coronal section shows the complex but smooth, looping course of the epidural catheter (arrow 
	), without kinking.
Fig. 1. (A  ) An axial computed tomography image shows the epidural catheter between the spinal lamina and the dural sac. The epidural catheter contains radiopaque metal spring coils. (B  ) A multiplanar reconstructed image of the lower thoracic spine in an oblique coronal section shows the complex but smooth, looping course of the epidural catheter (arrow  ), without kinking.
×
Fig. 2. Surface display images (three-dimensional) of the epidural catheter in the thoracic epidural space. The arrows depict the path of the catheter. The laminae were removed during the reconstruction process.
Fig. 2. Surface display images (three-dimensional) of the epidural catheter in the thoracic epidural space. The arrows depict the path of the catheter. The laminae were removed during the reconstruction process.
Fig. 2. Surface display images (three-dimensional) of the epidural catheter in the thoracic epidural space. The arrows depict the path of the catheter. The laminae were removed during the reconstruction process.
×