CASE STUDY CT features of rupture of the thoracic aorta and subsequent death F van Gelderen MD· A n 83-year-old man was found in a collapsed and dys- pnoeic condition at his home and suffered a period of ap- noea in transit to the hospi- tal. On examination he was hypotensive with bradycar- dia and weak femoral pulses. Chest radiographs re- vealed homogeneous opacifi- cation of the left hemithorax with relative sparing of the left base. The referring clini- cian considered the possibili- ties of rupture of the aorta or alternatively a mass in the left hemithorax; a left pleural tap revealed bloody fluid, and the patient was referred for com- puted tomography (CT). A limited non-contrast-enhanced CT examination confirmed the diag- nosis of aortic rupture. A dynamic contrast-enhanced examination dem- onstrated the signs to better advantage, with a large posterior 'encapsulated' extrapleural haematoma displacing the convex parietal pleura anteriorly. A smaller left anterior pleural fluid AM Packer MOCM** • Department of Radiology, •• Department of Pathology, Wanganui Base Hospital, Wanganui, New Zealand collection and marked mediastinal shift to the right side were present. The de- scending aorta was displaced anteriorly (Figure 1). An initially confusing feature was the absence of contrast medium in the aorta, and lingering of contrast in the venae cavae and azygos venous sys- tem. There was also extensive dense opacification of dilated veins, includ- ing the spinal epidural veins lining the inside of the bony vertebral column, with loss of the normal rounded con- tour. Venous channels within the soft tissues posterior to the vertebral col- umn and contrast filled intercostal, veins were also noted. Figure 1,' CT chest at TB level demonstrates a vel}' large left extrapleural fluid col/ection posteriorly, separated by antenorly bowed convex pleura, with intrepleural haemoth~rax more anteriorly (pleura indicated by arrows). Calcified aorta displaced anteriorly, and marked medlastmal shitt to the nght. Dense contrast layering in superior vena cava and high density vessels In chest wal/ (arrows). The spinal canal has lost ItS nor';lal rounded contour due to . opacification of intraspinal veins. (Pa!,ent s arms by his Side. with resulting artefacts and simulated low attenuation In postenor Mmlthorax ). 26 SA JOURNAL OF RADIOLOGY. November 1998 The dependent aspects of the he- patic veins (Figure 2), portal venous system (Figure 3) and right renal vein and radicles (Figure 4) were distended with contrast as if diagnostic venog- raphy had been performed. A poste- rior hepatic 'sinusoidogram' appear- ance was noted, with contrast readily filling the sinusoids in the dependent parts of the liver in a homogeneous t:-'0-pa-g-e-=27=---- CT features of rupture of the thoracic aorta and subsequent death frompage26 Figure 2: CT at T10- TIl disc level with very dense contrast medium in inferior vena cava (t/p of nasogastric tube to the left of the inferior vena cava), Hepatic vein (arrow) and radic/es distended with contrast medium, and sinusoids in dependent part of right lobe of liver homogeneously opacified, Note also opacification of venous channels related to posterior spinal elements at TI 0 level, within erector spinae muscles, The left extrapleuralilaematoma is again evident. Figure 3: CT at T12 level demonstrating similar features with contrast layering In the Inferior vena cava, the inferior aspect of the left extraplaural haamatoma still visible, contrast filled venous structures in the dependent erector spinae muscles, the sinusoidal opacification of the posterior aspect of the fiver and a contrast filled right portal vein (arrow), Figure 4: CT image at L l-L2 disc level demonstrating contrast layering in the inferior vena cava, flattening of the aorta from front to back, and very dense opacifieat/on of the right renal veins with an appearance similar to that of a diagnostic contrast renal venogram. 27 SA JOURNAL OF RADIOLOGY. November 1998 fashion, The parenchyma of the right kid- ney was not opacified in the same manner, possibly as the renal parenchyma is of firmer consistency, The contrast medium layering in the su- prarenal inferior vena cava was remarkable, but little filling of the infrarenal vena cava was present All veins and venous channels app ared to be dilated, but the aorta assumed a' collapsed' configuration, being wider from side to side (Figure 4), The patient died during th CT exami- nation, and the diagnosis of aortic rupture was confirmed at a subsequent post-mortem examination. The site of rupture was 9 cm inferior to the left subclavian artery, and the aorta was markedly atherosclerotic. Two li- tres ofleft-sided posterior extra pleural blood was found; the pleura was bowed anteriorly in convex fashion, A further litre of intrap- leural blood was found. The left lung was compressed and pale and weighed 340 g, and the right lung was rusty in colour, oedema- tous and weighed 760 g.There were signs of cardiomegaly and coronary atherosclerosis. The above case presentation includes some unusual features, with death during CT being an unusual event and documented thus in pictorial form. It is also worthy of note that a large extra pleural haemothorax is unu- sual following traumatic aortic rupture, with the apical cap sign and right paraspinalline displacement occurring in 10%, whereas a left haemothorax occurred in 16% of pa- tients. I At post-mortem examination the dis- tinction between extrapleural and pleural haemothorax is not usually made. The CT in the above case report was performed as an emergency procedure, but during the ex- amination it was decided that the patient would not be considered for resuscitation as a pre-existent diagnosis of Alzheimer's dis- ease had been communicated at that stage. Reference 1, Stark P, Traumatic rupture of the thoracic aorta; a review, CRC Critical Relliew il1 Diagnostic Imaging 1984; 21(3): 229-255,