Case Report Figure 3. Case 3. CTA of the left upper limb – CPR reconstruction. No contrast enhancement in the distal part of the brachial artery, for approx. 40 mm. Contrast enhancement of the forearm arteries. right, the anastomosis of the brachial artery was performed with the use of a venous graft. Due to an increasing oedema of the right upper limb, a follow-up postoperative CTA exam- ination was carried out (Figure 2B). It showed ulnar artery, in its whole length, and the radial artery narrowed, with a threadlike lumen from the point of its origin, visible till the half of the forearm only. After the examination, the right limb was operated on again. There was a clinical improve- ment of limb perfusion during patient’s hospitalisation. Case 3 Patient J.J., aged 60, was admitted to the emergency sur- gical department due to acute ischaemia of the left upper limb, resulting from an injury caused by an agricultural machine. The emergency CTA showed noncontrastet 40 mm segment of the brachial artery, at the level of the distal humerus and the elbow joint (Figure 3). Forearm arteries were normally contrasted via collateral circulation. The patient was operated on in an emergency setting. The part of the left brachial artery was reconstructed with a venous graft, which resulted in a clinical improvement and, finally, in a normal perfusion of the limb. Discussion Computed tomography angiography with the use of mul- tislice scanners (especially the 64-slice ones) becomes an excellent tool for arterial imaging [1]. Application of multi- ple rows of detectors, with a fast scanning rate and a high, sometimes also isotropic, resolution, led to the situation in which all previous limitations connected with the use of CT scanners of an older type were surmounted. Due to the advances in the development of CT scanners, the CTA examination was included in the diagnostic protocol of acute limb ischaemia, as a result of a TransAtlantic Inter- Society Consensus (TASC-II) in 2008 [2,3]. 96 © Pol J Radiol, 2010; 75(2): 94-97 Interruption of transarterial blood flow caused by arterial occlusion or narrowing, leads to a decreased tissue perfu- sion, which may, in a long run, cause the loss of the limb. In upper limb injuries leading to ischaemia, it is especially important to precisely locate the site of the vessel trau- ma [4,6]. Owing to rapid diagnostics, it is now possible to immediately introduce an appropriate treatment, which improves the prognosis of limb survival. Until recently, the basic method of arterial diagnostics was a standard arteriography. Despite its substantial precision, it is also highly invasive and expensive, and requires a group of specialised operators to perform it, which considerably increases the time of the procedure. A completely non-inva- sive Doppler ultrasonography technique is, on the other hand, much less sensitive than the CTA or the arteriography, and depends on the class of the applied unit, as well as on the experience of the operator. Another minimally invasive meth- od, i.e. MRI angiography, is not frequently performed in the diagnostics of acute posttraumatic limb ischaemia, due to the long examination time and a relatively low availability [7,8]. Nowadays, the most important alternative for the tradi- tional angiography in ALI diagnostics is the multislice spi- ral computed tomography angiography (CTA). The 64-slice scanners, thanks to a shorter acquisition time, allow for a one-time administration of the contrast medium and inves- tigation of extensive anatomical regions (such as blood ves- sels in the limbs) with a submillimetre (isotropic) resolution [8]. The main advantages of CTA include: short examination time (approx. 10 minutes including the preparation and positioning time) and minimal invasiveness. The replace- ment of the standard intraarterial arteriography with CTA, considerably decreases the risk of severe vascular compli- cations such as: bleeding, formation of pseudoaneurysms or acute limb ischaemia caused by a strong compression of the vessel after the procedure [9]. Despite those many advantages, CTA has its limitations as well. It may become diagnostically useless if the contrast agent flows into the examined vessel too early or too late in relation to the beginning of the examination. Such a situation may take place in patients with circulatory abnormalities, e.g. after a multiorgan trauma (when the contrast medium flows more slowly), or after injecting contrast agent to a unproper (too peripheral) vessel, due to which the concen- tration of the contrast medium in the vessels is too low. The next problem is presence of artefacts resulting from move- ments of the examined patients or from a poor contact or cooperation of the patient. Another limitation of CTA in the diagnostics of posttraumatic arterial injuries is the presence of artefacts caused by metal fragments in the vicinity of the analysed vessels, e.g. in case of gunshot wounds. They cause streaks that make the precise and correct evaluation of an image impossible. High incidence of metal fragments in the vicinity of blood vessels is one of the main limitations of CTA [7,9]. The above presented patients with posttraumatic acute ischaemia of the upper limbs were diagnosed with a 64-slice LightSpeed scanner (GE Healthcare). A correct per- formance of the examination required a proper position- ing of the patient (as far as the anatomy allowed), which