The Focal Hepatic ‘Hot Spot’ Sign of Superior Vena Cava Obstruction in Contrast-enhanced Computed Tomography
J Joseph, H Narayanan, H Babu, A Praveen
Hong Kong J Radiol 2010;13:26-8
In patients with superior vena caval obstruction, computed tomography of the liver in its arterial or early portal phase may show abnormal hyperattenuation in segment IV of the left hepatic lobe. This abnormal enhancement is due to porto-systemic venous shunting between the superior vena cava and portal vein. The 3 major collateral pathways after central venous obstruction in the thorax are the superior, posterior, and the anterolateral routes. In one of the anterolateral pathways, collateral veins return blood to the left hepatic lobe via the internal mammary and paraumbilical veins, thereby creating a ‘hot spot’ in the left hepatic lobe, around the union of the paraumbilical vein and left main branch of the portal vein. This is the equivalent of a similar sign described initially for radionuclide liver scans. The focal hepatic ‘hot spot’ sign in computed tomography should strongly suggest central venous obstruction in the thorax. We report a rare case, in which a radiological diagnosis of lung cancer and associated superior vena cava obstruction yielded an abnormal strong enhancement in the medial segment of left lobe of the liver during the arterial phase of helical computed tomography.
中文摘要
上腔靜脈阻塞在電腦斷層增強掃描上的局灶性肝臟「熱灶」
J Joseph, H Narayanan, H Babu, A Praveen
上腔靜脈阻塞患者的肝臟電腦斷層掃描動脈期或門脈早期可能顯示肝左葉IV段異常高密度。這種異 常强化由上腔靜脈與門靜脈之間的門﹣體分流導致。胸部中央靜脈阻塞後主要形成上方、後方及前 外側三種側枝循環通路。內乳靜脈及臍周靜脈的血液經前外側側枝循環之一回流至肝左葉，在臍周 靜脈與門靜脈左主枝的匯合處周圍形成「熱灶」。肝臟放射性核素掃描研究曾描述過類似現象。電 腦斷層掃描中的局灶性肝臟「熱灶」强烈提示胸內中央靜脈阻塞。本文報告一罕見病例，因肺癌伴 發上腔靜脈阻塞，其左肝葉內側段在螺旋電腦斷層掃描掃描動脈期出現高度强化。