Abstract：
OBJECTIVE: To present two cases of Internal Carotid Artery (ICA) agenesis and conduct a systematic review to assess for associations with other anomalies and intracranial aneurysms.
METHODS: We performed a retrospective review of published cases of patients with ICA agenesis with intercavernous anastomosis in MEDLINE database on August 2022 using search terms \"internal carotid artery\", \"agenesis\" and \"transcavernous anastomosis\". We also included two cases of ICA agenesis with type D collateral that we encountered.
RESULTS: Total of 46 studies that included 48 patients and two of our cases resulted in 50 patients. Only 70% of studies reported the location of a collateral vessel of which more than two-thirds were on the floor of sella. More than half of the vessels connected cavernous segments of ICA. A1 segment ipsilateral to the side of ICA agenesis was absent in most of the cases but was not true for all cases. Aneurysm was seen in more than one-quarter of the patients. It can also mimic microadenoma as in prior reported cases as well as in one of our cases.
CONCLUSIONS: ICA agenesis with type D collateral is a rare anomaly but clinically relevant due to the increased risk of an aneurysm or mimic microadenoma or false alarm for occlusion of ICA but knowledge of this rare variant can help in better management of these patients.
METHODS: We performed a retrospective review of published cases of patients with ICA agenesis with intercavernous anastomosis in MEDLINE database on August 2022 using search terms \"internal carotid artery\", \"agenesis\" and \"transcavernous anastomosis\". We also included two cases of ICA agenesis with type D collateral that we encountered.
RESULTS: Total of 46 studies that included 48 patients and two of our cases resulted in 50 patients. Only 70% of studies reported the location of a collateral vessel of which more than two-thirds were on the floor of sella. More than half of the vessels connected cavernous segments of ICA. A1 segment ipsilateral to the side of ICA agenesis was absent in most of the cases but was not true for all cases. Aneurysm was seen in more than one-quarter of the patients. It can also mimic microadenoma as in prior reported cases as well as in one of our cases.
CONCLUSIONS: ICA agenesis with type D collateral is a rare anomaly but clinically relevant due to the increased risk of an aneurysm or mimic microadenoma or false alarm for occlusion of ICA but knowledge of this rare variant can help in better management of these patients.
摘要：
目的：介绍两例颈内动脉（ICA）发育不全病例，并进行系统评价以评估与其他异常和颅内动脉瘤的关系。
方法：我们于2022年8月在MEDLINE数据库中使用搜索词“颈内动脉”对已发表的ICA发育不全合并海绵体间吻合的患者病例进行了回顾性审查，“发育不全”和“经海绵体吻合术”。我们还纳入了我们遇到的两例带有D型抵押品的ICA发育不全病例。
结果：共45项研究，包括47例患者，我们的2例病例中有49例患者。只有70％的研究报告了侧支血管的位置，其中三分之二以上位于蝶鞍的地板上。超过一半的血管连接ICA的海绵状段。在大多数情况下，不存在ICA发育不全一侧的A1段，但并非所有情况都如此。超过四分之一的患者出现动脉瘤。它也可以模拟微腺瘤，如先前报道的病例以及我们的病例之一。
结论：带有D型侧支的ICA发育不全是一种罕见的异常，但由于动脉瘤或模拟微腺瘤的风险增加或ICA闭塞的误报，具有临床意义，但对这种罕见变异的了解有助于更好地管理这些患者。
方法：我们于2022年8月在MEDLINE数据库中使用搜索词“颈内动脉”对已发表的ICA发育不全合并海绵体间吻合的患者病例进行了回顾性审查，“发育不全”和“经海绵体吻合术”。我们还纳入了我们遇到的两例带有D型抵押品的ICA发育不全病例。
结果：共45项研究，包括47例患者，我们的2例病例中有49例患者。只有70％的研究报告了侧支血管的位置，其中三分之二以上位于蝶鞍的地板上。超过一半的血管连接ICA的海绵状段。在大多数情况下，不存在ICA发育不全一侧的A1段，但并非所有情况都如此。超过四分之一的患者出现动脉瘤。它也可以模拟微腺瘤，如先前报道的病例以及我们的病例之一。
结论：带有D型侧支的ICA发育不全是一种罕见的异常，但由于动脉瘤或模拟微腺瘤的风险增加或ICA闭塞的误报，具有临床意义，但对这种罕见变异的了解有助于更好地管理这些患者。
