CT location distribution of subarachnoid hemorrhage and its value in intracranial aneurysm detection

Abstract

Objective To compare the CT location distribution of subarachnoid hemorrhage (SAH) caused by aneurysms at different locations, and to explore the value of CT hemorrhage distribution for improving the detection of aneurysms in CTA in diagnosing aneurysm. Methods Cerebral CT and CTA imaging of 415 patients with aneurysmal SAH from Beijing Tiantan Hospital, Capital Medical University from January 2019 to October 2020 were retrospectively analyzed. The differences of SAH location distribution caused by the aneurysms were compared, and the accuracy of aneurysm diagnosis between junior and senior radiologists were evaluated. Results A total of 415 patients had 463 aneurysms, including 324 type-Ⅰ aneurysms and 139 type-Ⅱ aneurysms. There were 415 responsible aneurysms, including 295 type-Ⅰ aneurysms and 120 type-Ⅱ aneurysms. SAH from type-Ⅰ aneurysms was mainly distributed in suprasellar cisterna (95.93%, 283/295), ambient cistern (90.17%, 266/295), longitudinal fissure (86.44%, 255/295), sylvian cistern (81.02%, 239/295), quadrigeminal cistern (61.69%, 182/295) and prepontine cistern (50.85%, 150/295). SAH from type-Ⅱ aneurysms was mainly distributed in sylvian cistern (85.83%, 103/120), longitudinal fissure (80.83%, 97/120), suprasellar cisterna (78.33%, 94/120), ambient cistern (77.50%, 93/120), prepontine cistern (67.50%, 81/120) and quadrigeminal cistern (66.67%, 80/120). The proportion of hemorrhage in suprasellar cisterna [95.93% (283/295) vs. 78.33% (94/120); χ² = 31.761, P = 0.001] and ambient cistern [90.17% (266/295) vs. 77.50% (93/120); χ² = 11.730, P = 0.001] was higher in type-Ⅰ aneurysms than that in type-Ⅱ aneurysms, and the proportion of hemorrhage in prepontine cistern was lower in type-Ⅰ aneurysms than that in type-Ⅱ aneurysms [50.85% (150/295) vs. 67.50% (81/120); χ² = 9.585, P = 0.002]. The overall rate of aneurysms detection and type-Ⅱ aneurysms detection in junior radiologists were lower than those in senior radiologists (paired χ² test: P = 0.000, 0.000). After the training of SAH distribution, the junior radiologists increased their detection rate of type -Ⅱaneurysms, and showed no significant difference compared with that of senior radiologists (paired χ² test: P = 0.146). Conclusions The CT distribution of aneurysmal SAH has regularity. It's important to summarize the characteristics of SAH for improving the detection of aneurysms.

doi：10.3969/j.issn.1672⁃6731.2022.07.012