Search Results (3)

Background/Objectives: The fetal-type posterior cerebral artery (fetal PCA) is an anatomical variant that alters hemodynamics and may influence posterior communicating artery (PCoA) aneurysm rupture risk. Aneurysm shape and size irregularity are key rupture predictors. This study investigates the impact of fetal PCA on PCoA aneurysm morphology and rupture risk using a radiomics-based approach. Methods: We retrospectively analyzed 87 patients with PCoA aneurysms (39 ruptured, 48 unruptured) treated at a tertiary center (January 2017–December 2022). Seventeen morphological parameters and 18 radiomic features were extracted per aneurysm. Patients were grouped by fetal PCA presence. Logistic regression and receiver operating characteristic (ROC) analyses identified rupture predictors. Results: Of 87 aneurysms, 38 had fetal PCA (24 ruptured, 14 unruptured), and 49 did not (15 ruptured, 34 unruptured). Fetal PCA was significantly associated with rupture (odds ratio [OR]: 3.28, p = 0.018). A higher non-sphericity index (NSI) correlated with rupture risk (OR: 3.35, p = 0.016). In non-fetal PCA aneurysms, size-related parameters such as height (6.83 ± 3.54 vs. 4.88 ± 2.57 mm, p = 0.034) and area (190.84 ± 167.08 vs. 107.94 ± 103.10 mm², p = 0.046) were key rupture predictors. In fetal PCA aneurysms, flow-related parameters like vessel angle (55.78 ± 31.39 vs. 38.51 ± 24.71, p = 0.035) were more influential. ROC analysis showed good discriminatory power, with an area under the curve: 0.726 for fetal PCA and 0.706 for NSI. Conclusions: Fetal PCA influences PCoA aneurysm rupture risk and morphology. NSI is a reliable rupture marker. Integrating morphological and anatomical data may improve rupture risk assessment and clinical decision-making. Full article

Background and Objectives: The microanatomy of the superior cerebellar artery (SCA) is clinically significant. We, thus, aimed at patterning unilateral and bilateral possibilities of SCA origin. Materials and Methods: In total, 205 archived records of computed tomography and magnetic resonance angiograms were used. There were defined types of SCA origin from the basilar artery (BA): “0”—absent SCA, “1”—preterminal, “2”—collateral SCA, with SCA appearing as a terminal branch of BA, and “3”—SCA from the posterior cerebral artery (PCA) of the cerebral type. Fenestrations and duplications of SCA were recorded. Bilateral combinations of types were recorded as follows: A (1 + 0), B (1 + 1), C (1 + 2), D (1 + 3), E (1 + duplicated SCA), F (2 + 2), G (2 + 3), H (3 + 3), I (3 + duplicated SCA), J (1 + fenestrated SCA). Results: Type 0 SCAs were found in 0.25%, type 1 in 71.29%, type 2 in 19.06%, and type 3 in 9.41%. Absent and fenestrated SCAs were each found in a single case. The most frequent combinations were B (58.05%), C (13.17%) and F (13.17%). Bilateral symmetrical types occurred in 70.7% of cases. Fetal types of PCA and the artery of Percheron modified the BA ends. Combinations of C, F, and G changed the BA ends or tips; thus, different subtypes resulted in five BA bifurcation patterns, including five BA trifurcations and one BA quadrifurcation. BA trifurcation was also found in cases with duplicated SCAs. Conclusions: The SCA has various anatomical possibilities of origin and bilateral combinations that are not presented in anatomical lectures. Details on the specific end of the BA should be gathered on a case-by-case basis. Full article

Background and Objectives: Anatomical variations of the arterial circle of Willis (cW) are common. A posterior cerebral artery (PCA) fed mostly or exclusively from the internal carotid artery is a fetal PCA (FPCA), partial (p-FPCA), or full/complete (f-FPCA), respectively. Because FPCA occurs in different anatomical configurations of the cW sides, we aimed to document in detail these morphological possibilities of FPCA within the cW. Materials and Methods: FPCAs were documented on a retrospective set of 139 computed tomography angiograms. Results: FPCAs were found in thirteen cases, nine males and four females. In 7/13 cases there were two modified sides of the cW. In 5/13 cases there were three altered sides of the cW. Another case with FPCA showed four altered sides of the cW. In 10/13 cases, FPCA was unilateral and in the other three cases it was bilateral. Compared to the overall group, unilateral p-FPCAs were found in 1.43%, while unilateral f-FPCAs were found in 5.75%. A bilateral p-FPCA-f-FPCA combination was found in 0.71% and a bilateral f-FPCA-f-FPCA combination occurred in 1.43%. An anatomically isolated ICA was found in just one case with bilateral f-FPCA (0.71%). In 7/13 FPCA cases there were arterial variants exclusively in the posterior cW. In the other 6/13 FPCA cases, there were variants in both anterior and posterior circulation. There were no statistically significant associations of FPCA with sex or age. The higher prevalence of right-sided FPCA was not statistically significant. Conclusions: Anatomical assessments of cW should be performed on a case-by-case basis, as they may correspond to different cW morphologies. Full article