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

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.