Measurement of the Thoracic Cord and Subarachnoid Space by CT Myelography in Normal Korean Adults

Keimyung Medical Journal 1988;7(2):236-242.

척추조영 전산화층촬영을 이용한 정상 한국성인의 흉추와 지주복하공의 측정

이진우; 김홍; 서수지; 주양구

Abstract

It is important to determine the normal range of the spinal cord dimension for screening or localizing spinal pathologic processes which could change the size of cord; such as intramedullary tumor; syringomyelia; radiation and trauma. Although CT has been used extensively for the evaluation of spinal disease; the spinal cord cannot be defined from the subarachnoid space and dura without intrathecal injection of a contrast medium. A few studies have been reported that determined the dimensions of normal spinal cord and subarachnoid space; and moreover; a cross-sectional area of the thoracic cord has not yet been known. CT measurements of coronal and sagittal diameters including the coss-sectional area in the thoracic spines were obtained in 31 cases of normal Korean adults who were undergoing the contrast (Isovist) myelography without any pathology in the thoracic spines. The results were as follows： 1. The transverse diameters of the thoracic cord were 9. lmm(SD 1.1) in level 1(T1); 7.9mm(SD 0. 8) in level 2(T5) and 7.3mm(SD 0.7) in level 3(T9). The sagittal diameters were 7.0mm(SD 0.9) in level 1; 6.1mm(SD 0. 8) in level 2; and 6.3mm(SD 0. 7) in level 3. 2. The transverse diameters of the thorthracic subarachnoid space were 15;8mm(SD 1.4) in level 1; 14.3mmCSD 1. 6) in level 2; and 13.9mm(SD 1. 3) in level 3. The sagittal diameters were 12.9mm (SD 1. 5); 12.3mm(SD 1. 3) and 11.6mm(SD 1. 5) in order of the levels. 3. The cross-sectional areas of the thoracic cord and the subarachnoid space were 58.0mm2 (SD 7.5) and 165.4mm2 (SD 27. 5) in level 1;46.4mm2(SD 6. 2) and 147.1mm2(SD 27. 3) in level 3 separately. 4. The shape of the thoracic cord was elliptical in the upper thoracic spines; then became more round in the lower thoracic levels. The cross-sectional area of the thoracic cord is relatively smaller in the midthoracic spines than those of the upper and lower thoracic spines.