Middle cerebral artery anatomical variations and aneurysms: a retrospective study based on computed tomography angiography findings.

BACKGROUND: Anatomical variations of the middle cerebral artery (MCA) are an important clinical issue, due to high prevalence of intracranial aneurysms. Anatomical variations of vessels can lead to higher shear stress, which is thought to be the main factor leading to aneurysm formation and consequently to higher prevalence of aneurysms. The aim of this study was to evaluate anatomy of the MCA; to classify MCA aneurysms using computed tomography angiography and to correlate anatomical variations of MCA and circle of Willis with prevalence of MCA aneurysms. MATERIALS AND METHODS: Two hundred and fifty patients without MCA aneurysms and 100 patients with unruptured MCA aneurysms were qualified for the study, with exclusion of patients after MCA clipping. Four aspects of MCA anatomy were evaluated: division point, its relation to the genu, distance to M1 division and the genu and domination of post-division trunks. RESULTS: Middle cerebral artery bifurcation was found in 86.2% and trifurcation in 13.8% of the cases. 78.4% of MCAs divided before the genu, 19.2% in the genu and 2.4% after the genu. Upper branch domination was seen in 26%, lower branch in 25.4%, middle branch in 4% and no domination in 44.6% of the cases. In the study group 116 aneurysms were found. 86.2% of the aneurysms were located in M1 division point, 6.9% in M2 segment, 3.4% near lenticulostriatae arteries and 3.4% near early cortical branches. The only anatomical variation, which had significantly higher prevalence in patients with left MCA aneurysms, was domination of upper post-division trunk of MCA. No other statistically significant differences in circle of Willis and MCA variations were found between patients with aneurysms and without them. CONCLUSIONS: The most common configuration of MCA is bifurcation before the genu with no dominating post-division trunk. Incidence of MCA aneurysms is not correlated with anatomical variations of MCA and the circle of Willis.

Configurations of the circle of Willis: a computed tomography angiography based study on a Polish population.

The aim of the study was to investigate the distribution of the circle of Willis variants in Polish population by means of computed tomography angiography (CTA). The results were then analysed and compared with another study that used similar methods but that was carried out on an ethnically distinct population. Patients presenting with intracranial pathology were excluded from the initial study population. In total, 250 CTA belonging to 129 female and 121 male patients were reviewed. A modified classification system of the circle was proposed, which took into consideration the anterior and the posterior aspects of the circle individually. The typical variant of Willis's circle occurred in 16.80% of cases. The anterior and the posterior portions of the circle were normal in 47.20% and 26.80% of the patients respectively. As for the anterior part, lack of the anterior communicating artery was the most frequent abnormality (22.80%). Bilateral absence of posterior communicating arteries was the most common anomaly in the posterior part of the circle (29.20%). This type of anomaly was also the most common, when taking into consideration the entire circle (12.00%). There were statistically significant differences between the age groups and genders when considering the occurrence of an incomplete circle. Overall, a substantial proportion of patients manifested clinically important variants that were incapable of providing collateral circulation. Comparison with other imaging-based and cadaveric studies revealed noticeable differences, that may have resulted from the variable technical features of other studies or other factors such as the ethnical origins of the studied populations.

MR Diffusion Anisotropy Imaging of Spinal Cord Mechanical Compression and Injury on the Rat Model. In Vivo.

The aim of this study was the application of magnetic resonance diffusion anisotropy imaging (MR DAI) for assessment of spinal cord compression (SCC) and injury (SCI) in rats depending on the time course from the moment of injury. Twenty rats were used, divided into three groups (five with no surgical operation, five with laminectomy only and ten with SCI produced using a dynamic weight - drop model). MR DAI was performed four times (1, 24, 48 and 168 hours after surgery) at 4.7 T with diffusion gradients applied parallel and perpendicular to the spine. Diffusion parameters (lADC, tADC and AI) were calculated for defined regions of white and gray matter. Epidural hematoma which appeared after laminectomy compressed spinal cord and caused a decrease of apparent diffusion coefficient (ADC) values in GM and WM. SCI in WM produced a decrease of lADC and increase in tADC. In GM an increase in both lADC and tADC values after SCI was observed. MR DAI will disclose dynamic changes in water diffusion during the first days after spinal cord contusion.

Surgical treatment of aortopulmonary window with tetralogy of Fallot.

An association between aortopulmonary window and tetralogy of Fallot is rare. We report a case of the combined anomalies in which, possibly for the first time, the diagnosis was made by echocardiography alone, and in which successful surgical treatment was performed in early infancy.