Computer-aided analysis of middle cerebral artery tortuosity: association with aneurysm development

Abstract

OBJECTIVE Blood vessel tortuosity may play an important role in the development of vessel abnormalities such as aneurysms. Currently, however, there are no studies analyzing the impact of brain blood vessel tortuosity on the risk of aneurysm formation. Therefore, the authors performed a computer-aided analysis of middle cerebral artery (MCA) tortuosity, especially among patients diagnosed with MCA aneurysms. METHODS Anatomy of the MCAs of 54 patients with unruptured MCA aneurysms was retrospectively analyzed, as was that of 54 sex-, age-, and vessel side-matched control patients without MCA aneurysms. From medical records, the authors obtained each patient's medical history including previous and current diseases and medications. For each patient, they calculated the following tortuosity descriptors: relative length (RL), sum of angle metrics (SOAM), triangular index (TI), product of angle distance (PAD), and inflection count metric (ICM). RESULTS Patients with an MCA aneurysm had significantly lower RLs (0.75 ± 0.09 vs 0.83 ± 0.08, p < 0.01), SOAMs (0.45 ± 0.10 vs 0.60 ± 0.17, p < 0.01), and PADs (0.34 ± 0.09 vs 0.50 ± 0.17, p < 0.01). They also had significantly higher TIs (0.87 ± 0.04 vs 0.81 ± 0.07, p < 0.01) and ICMs (3.07 ± 1.58 vs 2.26 ± 1.12, p < 0.01). Female patients had significantly higher RLs (0.76 ± 0.11 vs 0.80 ± 0.09, p = 0.03) than male patients. CONCLUSIONS Middle cerebral artery aneurysm formation is strongly associated with blood vessel tortuosity parameters, which can potentially be used to screen for patients at risk for MCA aneurysm formation.

Increased tortuosity of basilar artery might be associated with higher risk of aneurysm development

“…An interesting finding of this and our previous studies, in which we analysed tortuosity of MCA, ACA and ICA [12][13][14]25], are differences in contribution of certain tortuosity descriptors to risk of aneurysm development. For all four arteries, we found that increased values of TI were associated with higher risk of aneurysm presence.…”

“…It was shown before for aortic [10] and splenic artery [11] aneurysms. In terms of other cerebral vessels, a similar association was found for ICA [14,23], MCA [12], ACoA [13] and VA [24]. Additionally, increased tortuosity was associated with lower risk of intracranial aneurysm rupture [25] and inversely correlated with its size [13].…”

“…In other studies, higher tortuosity was linked to aortic aneurysm presence and risk of rupture [10], as well as to development of splenic artery aneurysm [11]. In our previous study, we have also proved that aneurysms of the middle cerebral artery (MCA) [12], anterior communicating artery (ACA) [13] and internal carotid artery (ICA) [14] are also linked to its tortuosity. However, these associations differed in terms of all used tortuosity descriptors.…”

Tortuosity of the Internal Carotid Artery and Its Clinical Significance in the Development of Aneurysms

“…Methods of artery tracking and details about the software used for this study were described in our previous work [15]. For each patient’s DSA, we extracted a curve representing the ICA intracranial course (C2–C7 segments) and measured its Relative Length (RL), Sum of Angle Metrics (SOAM), Product of Angle Distance (PAD), Triangular Index (TI), and Inflection Count Metrics (ICM).…”

“…As tortuosity promotes hemodynamic changes in blood flow, it can lead to the development of aneurysms. Such association was found in terms of the aorta [11] and splenic artery [12], as well as in brain arteries, such as the internal carotid artery (ICA) [13], basilar artery (BA) [14], middle cerebral artery (MCA) [15], and vertebral artery [16]. Our previous study suggested that tortuosity of the anterior cerebral artery might play a role in anterior communicating artery aneurysm rupture [17].…”