MDCT detection of left subclavian artery obstruction accompanied by anomalous origin of the left vertebral artery

Abstract

A 63-year-old man was referred to our hospital complaining worsening of severe left shoulder stiffness for one year. Systolic pressure of the left upper arm was 50 mm Hg lower than that of the right arm (75 mm Hg). He did not have episodes of dizziness or syncope upon left arm exercise. Multi-detector computed tomography (MDCT) angiography was performed using a LightSpeed 16 (GE Systems, USA) with the slice thickness of 0.625 mm. 80 ml of the contrast medium (Optiray 320; Tyco Healthcare, Japan) was used. MDCT revealed complete obstruction of the left subclavian artery (Fig 1a). The length of the obstruction was 30 mm. MDCT also revealed an unusual aortic arch variation (Fig 1a). The left vertebral artery originated directly from the arch between the left common carotid artery and the left subclavian artery. A collateral vessel to the distal site of the obstruction was also demonstrated (Fig 1b, large arrow). The left vertebral artery could not be identified in its usual location (Fig. 1b, small arrow). Selective digital subtraction angiography of the left subclavian artery demonstrated complete obstruction (length 28 mm) of the left subclavian artery. A collateral vessel was also demonstrated (Fig 2, arrow). The