Angiographic dimple of profound significance in cases of aneurysmal subarachnoid hemorrhage: report of 2 cases

摘要

The occurrence of an angiographic dimple or irregularity due to indentation of the contrast column by an intraluminal thrombus at the dome of a ruptured aneurysm is not uncommon and does not draw much clinical attention. However, an angiographic dimple at the base of the ruptured aneurysm or division of the parent artery can signify a rupture point close to the dimple and an intraluminal thrombus, which has utmost clinical significance as it is close to the parent artery and necessitates a different treatment strategy from rupture of the aneurysm dome. The author reports on 2 cases of an angiographic dimple following subarachnoid hemorrhage (SAH) and subsequent surgical exploration. In the first patient, a 57-year-old-woman, angiography revealed a basal dimple in a superiorly directed anterior communicating artery aneurysm. A pterional craniotomy was performed, which revealed a bibbed aneurysm harboring a superiorly directed unruptured lobule and inferiorly directed ruptured lobule. An intraluminal thrombus in the inferiorly directed lobule apparently obscured the lobule and caused the appearance of the basal dimple on the angiograms. In the second patient, a 40-year-old man who had been transferred to the author's institution because of an angiographic evaluation that did not show any aneurysm despite SAH in the basal cisterns, initial angiography revealed a subtle dimple on the superior wall of the anterior communicating artery (ACoA). On follow-up angiography, a very small aneurysm was seen at the site of the dimple. A craniotomy then revealed a very small ruptured and thrombosed aneurysm on the superior wall of the ACoA.