Figure 6k. True thoracic aneurysm in a 74-year-old man. (a) Oblique coronal MIP image from CT angiography shows a thoracic aneurysm with a stomach-like shape. (b) Coronal MPR image from MR angiography shows the anterior spinal artery and the artery of Adamkiewicz (arrow) branching from the left ninth intercostal artery. (c) Oblique sagittal MPR image from MR angiography shows a small left ninth intercostal artery (arrow) and a small collateral vessel between the left 9th and 10th intercostal arteries (arrowhead). (d, e) Oblique partial MIP images from MR angiography show stenosis of the left ninth intercostal artery (arrow in d) and a patent left 10th intercostal artery (e). (f) Oblique coronal MPR image from MR angiography also shows the small collateral vessel (arrow) between the left 9th and 10th intercostal arteries (cf c). A graft replacement of the descending aorta from the fifth to the ninth thoracic level was successfully performed. A distal anastomosis was created just above the 10th intercostal artery. The left ninth intercostal artery was sutured, and the left 10th intercostal artery was preserved without any reconstruction of intercostal arteries. No paraplegia occurred after surgical repair. (g) Postoperative volume-rendered image from CT angiography shows a patent left 10th intercostal artery (arrow). (h) Postoperative oblique sagittal MPR image from MR angiography shows dilatation of the collateral vessel between the left 9th and 10th intercostal arteries (arrow). (i, j) Postoperative axial MPR images from MR angiography show occlusion of the ninth intercostal artery (arrow in i) and a patent 10th intercostal artery (j). (k) Oblique coronal MPR image from MR angiography shows the dilated collateral vessel between the left 9th and 10th intercostal arteries (arrow). (l) Coronal MPR image from MR angiography shows a patent artery of Adamkiewicz (arrow) and anterior spinal artery.