PURPOSE: The goal of this study was to directly measure the association between the internal carotid artery (ICA) morphometry and the presence of ICA-posterior communicating artery (PCOM) aneurysm. MATERIALS AND METHODS: The authors intraoperatively measured the length of the supraclinoid ICA because it is impossible to radiologically determine the exact location of the anterior clinoid process. We used an image analyzer with a CT angiogram to measure the angle between the skull midline and the terminal segment of the ICA (ICA angle), as well as the diameter of the ICA. The lengths and diameters of the supraclinoid ICA and the ICA angle were compared among PCOM aneurysms, anterior communicating artery (ACOM) aneurysms, and middle cerebral artery (MCA) bifurcation aneurysms (n=27 each). Additionally, the lengths and the diameters of M1 and A1 were compared for each aneurysm. RESULTS: The lengths of the supraclinoid ICA were 11.9+/-2.3mm. The lengths of the supraclinoid ICA in patients with ICA-PCOM aneurysms (9.7+/-2.8mm) were shorter than those of patients with ACOM aneurysms (13.8+/-2.2mm, Student's t-test, p<0.001) and with MCA bifurcation aneurysms (12.2+/-1.9 mm, Student's t-test, p<0.001). The diameters of the supraclinoid ICA and A1 in patients with ACOM aneurysms were larger than those in patients with MCA bifurcation aneurysms (Student's t-test, p<0.05). There were no significant differences in the lengths of M1 and A1, ICA angle, or diameter of M1 for each aneurysm. CONCLUSION: These results suggest that the relatively shorter length of the supraclinoid ICA may be a novel risk factor for the development of ICA-PCOM aneurysm with higher hemodynamic stress.
Carotid Artery Diseases/congenital/*radiography ; Carotid Artery, Internal/abnormalities/*radiography ; Humans ; Intracranial Aneurysm/*radiography ; Risk Factors

*Abnormalities, Multiple/radiography ; Basilar Artery/*abnormalities ; Basilar Artery/radiography ; Carotid Artery, Internal/radiography ; Intracranial Aneurysm/*complications ; Intracranial Aneurysm/radiography ; Vertebral Artery/radiography

Two angiographic instances of anomalous external carotid artery (ECA) and internal carotid artery (ICA) anastomosis are described, each occurring at the C2-3 level and bearing remnants of proximal ICA. The ICA remnant of one patient (identifiable immediately upon bifurcation of the common carotid artery) was hypoplastic, and that of the other patient was an occluded arterial stump. These features are not typical of non-bifurcating ICA. The occipital artery originated from an anomalous connection in one instance and from the main trunk of the ECA (just past the ECA-ICA connection) in the other.
Adult ; Arterial Occlusive Diseases/radiography ; Carotid Artery, External/*abnormalities/radiography/surgery ; Carotid Artery, Internal/*abnormalities/radiography/surgery ; Cerebral Angiography ; Humans ; Intracranial Aneurysm/*radiography/surgery ; Male ; Middle Aged

Abnormalities, Multiple ; diagnostic imaging ; Basilar Artery ; abnormalities ; diagnostic imaging ; Carotid Artery, Internal ; diagnostic imaging ; Humans ; Intracranial Aneurysm ; complications ; diagnostic imaging ; Male ; Middle Aged ; Radiography ; Vertebral Artery ; diagnostic imaging

A 44-year-old woman who showed recurrent vitreous hemorrhages with vascular tortuosity received CT angiography which revealed an internal carotid artery aneurysm. A case of internal carotid aneurysm was associated with a pattern of retinal arteriolar tortuosity pathognomic for familial retinal arterial tortuosity (fRAT), suggesting possible involvement of the cerebral circulation. We present a case of internal carotid aneurysm associated with a pattern of retinal arteriolar tortuosity pathognomic for fRAT.
Adult ; Aneurysm/*complications/radiography ; Angiography ; Carotid Artery Diseases/*complications/radiography ; *Carotid Artery, Internal ; Diagnosis, Differential ; Eye Abnormalities/complications/diagnosis/*genetics ; Female ; Follow-Up Studies ; Humans ; Retinal Artery/*abnormalities ; Tomography, X-Ray Computed ; Torsion Abnormality/complications/diagnosis/*genetics ; Visual Acuity