 Good day. My paper presentation title is a rare location of bi-lobed pseudo aneurysm. The first author is me, Dr. Archana Ravindra, a resident in D.Y. Patil Hospital, Navi Mumbai. The second author is Dr. Rohan Savant, assistant professor. And the third author is Dr. Pritik Patil, assistant professor. The aim of this is to radiologically evaluate a case of 38 year old male who presented with complaints of pain and swelling over the left forearm. On detailed history, the patient accounts for a short injury to the mid forearm. Introduction. Traumatic injuries of the limbs may affect the arteries and veins, generally triggering acute pathologies such as bleeding and ischemia. Post-traumatic presentations include occlusion and dissection. Pseudo aneurysm is a rare and late complication of penetrating trunk. Pseudo aneurysms are abnormal outpouchings of the arteries bounded only by the tunica adventitia. The outermost layer of the arterial wall formed due to a disruption in the arterial wall continuity. The possibility of its rupture is markedly higher than that of a true aneurysm of similar size due to poor support of the wall and thus requires swift treatment. The advent of noninvasive radio diagnostic modalities, example ultrasound and CT, it has a greater sensitivity for asymptomatic diseases and has allowed for quicker diagnosis and hence prevents high morbidity and mortality rates due to pseudo aneurysm. Here, we work up and help determine the cause, the location, morphological features and rupture risk of pseudo aneurysm of a post-traumatic limb. Materials and methods. Following a detailed clinical examination with informed consent, ultrasoundography in B mode color and spectral Doppler was performed as an initial investigation. Left forearm was evaluated using a high frequency linear probe. Following ultrasound contrast enhanced CT angiography of the upper limb was performed for reaching a final diagnosis and a more accurate conclusion. The following were the results. On ultrasound in B mode, we see an anechoic lesion. On putting Doppler to this lesion, we see swirling flow as evident by different color signal within the same lesion. The swirling flow is evident and is characteristically called the yin yang sign within the same lesion which represents the turbulent forward and backward flow. Next, CT. This is a coronal image and a sagittal image. We found an 18 by 2 mm sized focal out pouching involving the radial artery. You can see the radial artery pointed with the yellow arrow. This focal out pouching was 1.2 centimeters away from its bifurcation of the brachial artery. A contrast blush marked in red arrow is seen on the angioimages extending from the radial artery into the out pouching. Now we go into the axial video. First we are tracing the brachial artery that divides into on the left side is the ulnar and on the right side we see the vascular blush, the contrast blush coming from the radial artery. Next, in the first image in run one, we view an out pouching from the radial artery demonstrating incomplete enhancement seen with the red arrow. The wall of the pseudo aneurysm as we can see is smooth and well delineated, which is normal in cases of a post traumatic patients. Very rarely a pseudo aneurysm can have a thick and irregular or ill defined wall, which is generally seen in mycotic pseudo aneurysm. We can also see in the second run, the entire pseudo aneurysm appears filled with contrast material in the sequential run. It's pointed with the yellow arrow. And we can see that there is absence of a low attenuation area within. Sometimes in pseudo aneurysms due to partial thrombosis, there is presence of a low attenuation area, which is non enhancing. Next, this is a coronal image. We see the proximal out pouching, which is demonstrated with homogenous enhancement. And then we found another distance out pouching, which showed incomplete and dependent enhancement on you on routine usg which was our initial investigation. We were not able to find this second load of the by load pseudo aneurysm with this CT and geography in the third run we were able to accurately diagnose that it was a by lobed pseudo aneurysm. As we know by lobed pseudo aneurysm have higher risk of rupture. As we can see the adjacent area in this image, generally the attenuation adjacent to the pseudo aneurysm if high could indicate pseudo aneurysm rupture. The attenuation of course varies with chronicity. In this image the surrounding area adjacent to the pseudo aneurysm and the radial artery is of low attenuation. It's marked in the yellow arrow, it's 15 into 7.6 centimeters indicating hematoma formation, likely chronic in condition. However, we can see that there was no contrast extervation to suggest rupture. Next, a repeat usg was performed after the edema and swelling reduced in the patient and retrospectively we could visualize the proximal marked in red as well as the distal lobes of the by lobed pseudo aneurysm discussion. Tragic outcomes occur when penetrating traumas occur. When vascular lesions are suspected in the body, non invasive radio diagnostic modalities like I said ultrasound and CT with a greater sensitivity is an effective approach for detection and also for planning of intervention. Here in this case, we were not only able to help determine the cause, which we now know is trauma more likely than infection, the location, which we know is in the forearm and it's arising from the radial artery morphological features such as that it's the world and moderate sized and its rupture risk because it's by low. All these characteristics of the pseudo aneurysm, we were able to delineate but also we were able to assess other comorbidities of the patient, we were also able to evaluate surrounding structures, example the muscles and the hematoma that we saw and relevant vascular anatomy information example we were able to delineate the vascular artery as well as the ulnar artery. All of this is also essential for treatment planning. Fortunately, CT angiography was of great value for confirming the pseudo aneurysm in this post traumatic limb of a 38 year old male and for identifying its by lobed nature. These were my references very few cases were found of pseudo aneurysm in the radial artery and in upper limbs in general, especially a by lobed pseudo aneurysm is a very, very rare location is a very, very rare presentation. Thank you.